ccsm 0.16.0

#[allow(dead_code)]
mod config;
#[allow(dead_code)]
mod consumer;
#[allow(dead_code)]
mod registry;
#[allow(dead_code)]
mod sequence;
#[allow(dead_code)]
mod session;
#[allow(dead_code)]
pub(crate) mod commands;

use std::path::PathBuf;

use anyhow::Context;
use clap::{Parser, Subcommand};
use crate::consumer::Consumer;
use crate::registry::{parse_sections, now_iso as now_iso_ts};

// ── Structured Error Codes ─────────────────────────────────────────────

/// Error codes for structured error output. Agents grep for `[ERR_*]` to
/// programmatically distinguish error types.
#[derive(Debug, Clone, Copy)]
#[allow(dead_code)]
pub(crate) enum ErrorCode {
    NoSession,
    Exists,
    BadStatus,
    Gate,
    Invalid,
    Section,
    Dep,
    Consumer,
    Generic,
}

impl std::fmt::Display for ErrorCode {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        match self {
            Self::NoSession => write!(f, "[ERR_NOSESSION]"),
            Self::Exists => write!(f, "[ERR_EXISTS]"),
            Self::BadStatus => write!(f, "[ERR_BADSTATUS]"),
            Self::Gate => write!(f, "[ERR_GATE]"),
            Self::Invalid => write!(f, "[ERR_INVALID]"),
            Self::Section => write!(f, "[ERR_SECTION]"),
            Self::Dep => write!(f, "[ERR_DEP]"),
            Self::Consumer => write!(f, "[ERR_CONSUMER]"),
            Self::Generic => write!(f, "[ERR_GENERIC]"),
        }
    }
}

// ── CLI (clap) ──────────────────────────────────────────────────────

#[derive(Parser)]
#[command(name = "ccsm", version, about = "Session registry CLI", long_about = None)]
struct Cli {
    /// Target agent: auto-detected (opencode, claude, or pi). Also via CCSM_CONSUMER env var.
    #[arg(long)]
    consumer: Option<String>,

    /// Workspace directory (defaults to $PWD, then CCSM_WORKSPACE env var, then walk-up)
    #[arg(short = 'w', long)]
    workspace: Option<PathBuf>,

    #[command(subcommand)]
    command: Commands,
}

#[derive(Subcommand)]
enum Commands {
    /// Compact scan-friendly output for agents and humans.
    ///
    /// One record per line, grouped by group. Grep-friendly field markers
    /// (group:name, tags:t1,t2). Built-in --search makes grep optional.
    /// --json for structured output.
    #[command(visible_alias = "sc")]
    Scan {
        /// Filter by group name
        #[arg(short = 'g', long)]
        group: Option<String>,
        /// Filter by status
        #[arg(short = 'S', long)]
        status: Option<String>,
        /// Full-text search across name, goal, and tags (case-insensitive)
        #[arg(long)]
        search: Option<String>,
        /// Output as JSON array
        #[arg(long)]
        json: bool,
    },
    /// List sessions. --active (in_progress+blocked), --summary (counts), --status <s> (filter)
    #[command(visible_alias = "ls", visible_alias = "sessions", visible_alias = "s")]
    List {
        /// Only in_progress + blocked
        #[arg(short = 'a', long)]
        active: bool,
        /// Counts per status only
        #[arg(short = 's', long)]
        summary: bool,
        /// Filter by status. Pass "help" to see what each status means.
        #[arg(short = 'S', long)]
        status: Option<String>,
        /// Verbose: show full goal + tags (teammate scan mode)
        #[arg(short = 'v', long)]
        verbose: bool,
        /// Filter by group name
        #[arg(short = 'g', long)]
        group: Option<String>,
        /// Sort by rank within group
        #[arg(long)]
        by_rank: bool,
        /// Output as JSON array
        #[arg(long)]
        json: bool,
    },
    /// Show goal, scope, tags, session_id, pids, timestamps for a session
    Show {
        name: String,
        /// Extract one section from the detail file (e.g. "progress-log")
        #[arg(short = 'S', long)]
        section: Option<String>,
        /// Output as JSON object
        #[arg(long)]
        json: bool,
    },
    /// Create a pending entry. Optionally embed a ## Checklist section (-c <type>).
    ///
    /// Without -c the detail file stays minimal (no checklist). Add one later with `ccsm checklist --init`.
    /// Use -c with a type like feat/fix/research/chore to pre-populate type-specific items.
    ///
    /// Examples:
    ///   ccsm new my-feature -g "Add dark mode"
    ///   ccsm new my-feature -c -g "Add dark mode with checklist"
    ///   ccsm new my-feature -c feat -g "Add checklist from feat template"
    ///   ccsm new my-feature -b feat/my-branch -g "Work on my feature"
    New {
        /// kebab-case session name
        name: String,
        /// One-sentence goal
        #[arg(short = 'g', long)]
        goal: Option<String>,
        /// Skip fuzzy duplicate detection
        #[arg(short = 'f', long)]
        force: bool,
        /// Add checklist section. Optionally specify template type (feat/fix/research/chore)
        #[arg(short = 'c', long, num_args = 0..=1, default_missing_value = "default")]
        checklist: Option<String>,
        /// Target git branch (metadata only — ccsm warns on mismatch at resume)
        #[arg(short = 'b', long)]
        branch: Option<String>,
        /// Use a git worktree for this session (isolated checkout)
        #[arg(short = 'w', long = "worktree")]
        worktree: bool,
    },
    /// pending → in_progress. With --worktree, also creates a git worktree.
    Start {
        name: String,
        /// Enable worktree for this start (overrides session's use_worktree)
        #[arg(short = 'w', long = "worktree")]
        worktree: bool,
    },
    /// in_progress → completed, sets completed timestamp
    Complete {
        name: String,
        /// Skip gate checks (detail file completeness etc.)
        #[arg(short = 'f', long)]
        force: bool,
    },
    /// in_progress → blocked (waiting on dependency)
    Block { name: String },
    /// in_progress → abandoned (no longer relevant)
    Abandon { name: String },
    /// Reset to pending, clears session_id + pids + timestamps
    Pending { name: String },
    /// Set scope: 2-4 sentences on approach, constraints, what's in/out
    Scope {
        name: String,
        #[arg(num_args = 1..)]
        text: Vec<String>,
    },
    /// Replace tags (space-separated)
    Tag {
        name: String,
        #[arg(num_args = 1..)]
        tags: Vec<String>,
    },
    /// Set, clear, or overview a session group.
    ///
    /// `ccsm group --list` — list all groups in the workspace.
    /// `ccsm group <name>` — show all sessions in the group + goal from group detail file.
    /// `ccsm group <name> --roadmap` — render a markdown roadmap for the group.
    /// `ccsm group <name> --goal <text>` — set the group goal in the group detail file.
    /// `ccsm group <session> --group <g> [--rank free|<n>]` — assign to group.
    /// `ccsm group <session> --clear` — remove from group.
    ///
    /// Group detail files live at `~/.ccsm/<id>/session-group/<name>.md`.
    /// Auto-created on first join, auto-deleted when the last session leaves.
    Group {
        /// Session name (for --group/--clear) or group name (overview, when no flags given)
        name: Option<String>,
        /// List all groups in the workspace
        #[arg(short = 'l', long)]
        list: bool,
        /// Assign session to this group
        #[arg(short = 'g', long)]
        group: Option<String>,
        /// Rank: "free" or a number (lower = higher priority)
        #[arg(short = 'r', long)]
        rank: Option<String>,
        /// Remove session from its group
        #[arg(long)]
        clear: bool,
        /// Set the group goal (use with group name, not --group/--clear)
        #[arg(long)]
        goal: Option<String>,
        /// Render a markdown roadmap for the group (table + dependency graph, pipeable to file)
        #[arg(long)]
        roadmap: bool,
    },
    /// Print the next session to work on in a group.
    ///
    /// Priority: in_progress > pending by rank (numeric: lowest first, free: alphabetical).
    /// Exits 0 with no output if all sessions in the group are done.
    Next {
        /// Group name
        group: String,
    },
    /// Show dependency tree for a group.
    ///
    /// `ccsm group-deps <name>` — render the dependency graph for all sessions in a group.
    GroupDeps {
        /// Group name
        group: String,
    },
    /// Manage session dependencies.
    ///
    /// `ccsm depend <name> --on <dep>` — add a dependency.
    /// `ccsm depend <name> --clear` — remove all dependencies.
    /// `ccsm depend <name>` — list dependencies.
    Depend {
        /// Session name
        name: String,
        /// Add a dependency (session must complete first)
        #[arg(long)]
        on: Option<String>,
        /// Remove all dependencies
        #[arg(long)]
        clear: bool,
    },
    /// Manually link a Claude session_id. Auto-managed by `resume`.
    Attach {
        name: String,
        /// Session UUID (from ~/.claude/sessions/<pid>.json). Omit if using --pid.
        session_id: Option<String>,
        /// Harvest session_id from a live session file by PID.
        #[arg(long)]
        pid: Option<u32>,
    },
    /// Rename a session: registry entry, detail file, live session files, and transcript.
    /// Use -g and -s to refresh the topic at the same time.
    Rename {
        /// Current session name
        old: String,
        /// New session name (kebab-case)
        new: String,
        /// New goal (for topic change)
        #[arg(short = 'g', long)]
        goal: Option<String>,
        /// New scope (for topic change)
        #[arg(short = 's', long)]
        scope: Option<String>,
    },
    /// Spawn claude. --resume if session_id set, -n <name>, harvests session_id on exit.
    /// With --worktree, creates a git worktree first and resumes inside it.
    Resume {
        name: String,
        /// Create a git worktree and resume inside it
        #[arg(short = 'w', long = "worktree")]
        worktree: bool,
    },
    /// Retire current Claude session, spawn a fresh one for the same ccsm session.
    /// Use when context is bloated (>40%) and the model gets biased.
    Refresh {
        name: String,
        /// Why the refresh (logged to retired_session_ids)
        #[arg(short = 'r', long)]
        reason: Option<String>,
    },
    /// Soft-delete → trashed. Recoverable. Trash first, then `clean` to nuke.
    Trash { name: String },
    /// trashed → in_progress
    Recover { name: String },
    /// Permanently delete transcript + session files + entry. Irreversible.
    Clean { name: String },
    /// Pre-completion gate: check detail file completeness, print self-review checklist.
    /// Exits non-zero if the detail file is hollow. Run before `ccsm complete`.
    Close { name: String },
    /// List checklist items from the session detail file.
    ///
    /// The ## Checklist section is opt-in — add it with `ccsm new -c` or `ccsm checklist --init`.
    ///
    /// Checkbox format in the detail file:
    ///   - [ ] pending
    ///   - [x] done
    ///   - [~] skipped
    ///   - [!] blocked
    ///
    /// The close gate blocks completion while pending or blocked items remain.
    Checklist {
        name: String,
        /// Add ## Checklist section to detail file if it doesn't exist yet
        #[arg(short = 'i', long)]
        init: bool,
    },
    /// Toggle a checklist item's checkbox in the detail file, or add a new item.
    ///
    /// ITEM is a 1-based number, text substring to match, or new item text.
    /// When no existing item matches (by number or text), a new item is added.
    /// If the ## Checklist section doesn't exist, it's auto-created.
    ///
    /// Examples:
    ///   ccsm check my-session "write tests" -s pending    # add new item
    ///   ccsm check my-session 1 -s done                   # mark #1 done
    ///   ccsm check my-session "write tests" -s skipped    # mark by text match
    Check {
        name: String,
        /// 1-based index (1, 2, 3…) or text substring to match
        item: String,
        /// Target status: pending, done, skipped, blocked
        #[arg(short = 's', long)]
        status: String,
    },
    /// Stop-hook helper: if working tree is dirty, remind to update session detail.
    /// Auto-discovers the in_progress session. Silent when clean or recently noted.
    NoteCheck,
    /// Permanently delete ALL trashed entries. Irreversible.
    CleanAll,
    /// Archive transcript + session files, keep registry entry as work log
    Archive { name: String },
    /// Archive all completed sessions that still have transcripts
    ArchiveAll,
    /// Scan for health issues: orphaned IDs, dead PIDs, empty fields, cleanup candidates
    Doctor,
    /// Run multiple mutations in a single lock/load/save cycle.
    /// Each -q starts an operation: -q start foo -q scope foo text -q complete foo
    Sequence {
        #[arg(num_args = 1.., required = true, allow_hyphen_values = true)]
        args: Vec<String>,
    },
    /// Append a timestamped entry to the session detail file's Progress Log
    Note {
        name: String,
        #[arg(num_args = 1..)]
        text: Vec<String>,
        /// Cross-session note: auto-prepend "CROSS-SESSION [source]: " to the note
        #[arg(short = 'x', long)]
        cross: Option<String>,
    },
    /// Generate shell completion script (bash, fish, zsh)
    Completions {
        /// Shell: bash, fish, or zsh
        shell: String,
    },
    /// Output a system-reminder block with the active session's goal and scope.
    /// Used by SystemMessage hook to inject session context every turn.
    InjectScope {
        /// Session name (auto-detects in_progress if omitted)
        name: Option<String>,
    },
    /// Check if current work aligns with session scope. Exit 0 = pass, 1 = fail.
    /// Designed for Stop hook before `ccsm complete`.
    GateCheck {
        /// Session name (auto-detects in_progress if omitted)
        name: Option<String>,
        /// Strict mode: fail if scope is empty or unfilled
        #[arg(short = 'S', long)]
        strict: bool,
    },
    /// Install session tracking into global CLAUDE.md + skills (run once)
    Setup,
    /// Migrate registry + detail files from `.claude/` to `.ccsm/`.
    /// Leaves agent transcripts in their original locations.
    MigrateCcsm,
    /// Set or clear the target git branch for a session.
    ///
    /// This is metadata only — ccsm does not create or switch branches.
    /// Use `ccsm branch <name> <branch>` to set, `ccsm branch <name> --clear` to clear.
    Branch {
        name: String,
        /// Clear the branch field
        #[arg(long)]
        clear: bool,
        #[arg(num_args = 1..)]
        branch: Vec<String>,
    },
}

// ─────────────────────────────────────────────────────────────────────

fn main() -> anyhow::Result<()> {
    let cli = Cli::parse();
    let home = PathBuf::from(std::env::var("HOME").unwrap_or_else(|_| ".".into()));
    let consumer = Consumer::detect(&home, cli.consumer.as_deref());

    // Resolve workspace root: --workspace flag > CCSM_WORKSPACE env > walk-up > PWD
    // We chdir so every downstream function reads the right registry via PWD.
    if let Some(ref ws) = cli.workspace {
        std::env::set_current_dir(ws)?;
    } else if let Some(auto_ws) = resolve_workspace()? {
        std::env::set_current_dir(&auto_ws)?;
    }

    match cli.command {
        Commands::Scan { group, status, search, json } => run_scan(group.as_deref(), status.as_deref(), search.as_deref(), json),
        Commands::List { active, summary, status, verbose, group, by_rank, json } => run_list(active, summary, verbose, status.as_deref(), group.as_deref(), by_rank, json),
        Commands::Show { name, section, json } => run_show(&name, section.as_deref(), json, consumer),
        Commands::New { name, goal, force, checklist, branch, worktree } => run_new(&name, goal.as_deref().unwrap_or(""), force, checklist, branch.as_deref().unwrap_or(""), worktree, consumer),
        Commands::Start { name, worktree } => run_start(&name, worktree),
        Commands::Complete { name, force } => run_complete(&name, force),
        Commands::Block { name } => run_status(&name, "block", false),
        Commands::Abandon { name } => run_status(&name, "abandon", false),
        Commands::Pending { name } => run_pending(&name),
        Commands::Scope { name, text } => run_set_field(&name, "scope", &text.join(" ")),
        Commands::Tag { name, tags } => run_set_tags(&name, &tags),
        Commands::Branch { name, clear, branch } => run_branch(&name, clear, branch.as_slice()),
        Commands::Group { name, list, group, rank, clear, goal, roadmap } => run_group(name.as_deref(), list, group.as_deref(), rank.as_deref(), clear, goal.as_deref(), roadmap),
        Commands::Next { group } => run_next(&group),
        Commands::GroupDeps { group } => run_group_deps(&group),
        Commands::Depend { name, on, clear } => run_depend(&name, on.as_deref(), clear),
        Commands::Attach { name, session_id, pid } => run_attach(&name, session_id.as_deref(), pid, &home, consumer),
        Commands::Rename { old, new, goal, scope } => run_rename(&old, &new, goal.as_deref(), scope.as_deref(), &home, &workspace_path(), consumer),
        Commands::Resume { name, worktree } => commands::resume::run_resume(&name, &workspace_path(), &home, consumer, worktree),
        Commands::Refresh { name, reason } => run_refresh(&name, reason.as_deref(), &workspace_path(), &home, consumer),
        Commands::Trash { name } => run_trash(&name),
        Commands::Recover { name } => run_recover(&name),
        Commands::Clean { name } => run_clean(&name, &home, &workspace_path(), consumer),
        Commands::Close { name } => run_close(&name),
        Commands::Checklist { name, init } => run_checklist(&name, init),
        Commands::Check { name, item, status } => run_check(&name, &item, &status),
        Commands::NoteCheck => run_note_check(),
        Commands::CleanAll => run_clean_all(&home, &workspace_path(), consumer),
        Commands::Archive { name } => run_archive(&name, &home, &workspace_path(), consumer),
        Commands::ArchiveAll => run_archive_all(&home, &workspace_path(), consumer),
        Commands::Doctor => commands::doctor::run_doctor(&home, &workspace_path()),
        Commands::Sequence { args } => run_sequence(&args),
        Commands::Note { name, text, cross } => run_note(&name, &text.join(" "), cross.as_deref()),
        Commands::Completions { shell } => run_completions(&shell),
        Commands::InjectScope { name } => run_inject_scope(name.as_deref(), consumer),
        Commands::GateCheck { name, strict } => run_gate_check(name.as_deref(), strict),
        Commands::Setup => run_setup(&std::env::args().next().unwrap_or_else(|| "ccsm".into()), consumer),
        Commands::MigrateCcsm => run_migrate_ccsm(&workspace_path(), &home),

    }
}
// ── Workspace Resolution ───────────────────────────────────────────────

/// Resolve the workspace root directory, checking sources in priority order:
///
/// 1. **`--workspace` flag** — handled upstream in `main()` via `set_current_dir`
/// 2. **`CCSM_WORKSPACE` env var** — must be an absolute path to an existing dir
/// 3. **Walk up** from PWD looking for `.ccsm` identity file (via `resolve_or_create_identity`)
/// 4. **PWD** as-is (current behavior, fallback when no marker is found)
///
/// Returns `None` when no auto-detection succeeds — the caller uses PWD directly.
fn resolve_workspace() -> anyhow::Result<Option<PathBuf>> {
    // Priority: CCSM_WORKSPACE env var
    if let Ok(ws) = std::env::var("CCSM_WORKSPACE") {
        if !ws.is_empty() {
            let path = PathBuf::from(&ws);
            anyhow::ensure!(
                path.is_absolute(),
                "CCSM_WORKSPACE must be an absolute path, got: {}",
                ws,
            );
            anyhow::ensure!(
                path.is_dir(),
                "CCSM_WORKSPACE points to a non-existent directory: {}",
                ws,
            );
            return Ok(Some(path));
        }
    }

    // Priority: walk up from PWD looking for .ccsm identity file
    // Stops at the innermost match (closest to PWD).
    if let Ok(ctx) = crate::registry::resolve_or_create_identity() {
        return Ok(Some(ctx.root));
    }

    // No auto-detection — PWD will be used
    Ok(None)
}

/// Current working directory. `resolve_workspace()` is called at startup to
/// `chdir` into the right workspace, so this reflects the resolved workspace.
fn workspace_path() -> PathBuf {
    std::env::current_dir().unwrap_or_else(|_| PathBuf::from("."))
}

fn load_workspace_registry() -> anyhow::Result<crate::registry::WorkspaceRegistry> {
    crate::registry::WorkspaceRegistry::load()
}

/// Check if CCSM_OUTPUT_FORMAT=json is set for global JSON output mode.
/// Individual `--json` flags take precedence over this env var.
fn output_format_json() -> bool {
    matches!(
        std::env::var("CCSM_OUTPUT_FORMAT").ok().as_deref(),
        Some("json") | Some("JSON")
    )
}

/// Print a mutation result as either JSON or a structured text line.
fn action_msg(action: &str, name: &str, detail: &str) {
    if output_format_json() {
        let msg = serde_json::json!({
            "ok": true,
            "action": action,
            "name": name,
            "detail": detail,
        });
        println!("{}", msg);
    } else {
        println!("{:12}  {}  ← {}", action, name, detail);
    }
}

/// `ccsm scan` — compact scan-friendly output, grouped by group.
///
/// Format (text): `icon  name  goal  tags_csv` under `#group:<name>` headers.
/// Format (json): array of {name, status, group, rank, goal, tags, depends_on}.
///
/// Built-in --search makes grep unnecessary for agents. --json for structured consumers.
fn run_scan(group_filter: Option<&str>, status_filter: Option<&str>, search: Option<&str>, json: bool) -> anyhow::Result<()> {
    use crate::registry::SessionStatus;
    let reg = load_workspace_registry()?;

    let status: Option<SessionStatus> = match status_filter {
        Some("pending") => Some(SessionStatus::Pending),
        Some("in_progress") | Some("in-progress") => Some(SessionStatus::InProgress),
        Some("completed") => Some(SessionStatus::Completed),
        Some("blocked") => Some(SessionStatus::Blocked),
        Some("abandoned") => Some(SessionStatus::Abandoned),
        Some("trashed") => Some(SessionStatus::Trashed),
        Some(other) => {
            anyhow::bail!("{} unknown status '{}' — valid: pending, in_progress, completed, blocked, abandoned, trashed", ErrorCode::BadStatus, other);
        }
        None => None,
    };

    // Collect filtered sessions
    let sessions: Vec<&crate::registry::WorkspaceSession> = reg.sessions.iter()
        .filter(|s| {
            if let Some(g) = group_filter {
                if !s.group.as_ref().is_some_and(|grp| grp.name == g) { return false; }
            }
            if let Some(fs) = status {
                if s.status != fs { return false; }
            }
            if let Some(q) = search {
                let qlower = q.to_lowercase();
                let in_name = s.name.to_lowercase().contains(&qlower);
                let in_goal = s.goal.to_lowercase().contains(&qlower);
                let in_tags = s.tags.iter().any(|t| t.to_lowercase().contains(&qlower));
                if !in_name && !in_goal && !in_tags { return false; }
            }
            true
        })
        .collect();

    let use_json = json || output_format_json();

    if sessions.is_empty() {
        if use_json {
            println!("[]");
        } else {
            println!("(no matching sessions)");
        }
        return Ok(());
    }

    if use_json {
        #[derive(serde::Serialize)]
        struct ScanEntry {
            name: String,
            status: String,
            group: Option<String>,
            rank: Option<String>,
            goal: String,
            tags: Vec<String>,
            depends_on: Vec<String>,
            branch: String,
        }
        let entries: Vec<ScanEntry> = sessions.iter().map(|s| {
            ScanEntry {
                name: s.name.clone(),
                status: s.status.to_string(),
                group: s.group.as_ref().map(|g| g.name.clone()),
                rank: s.group.as_ref().map(|g| g.rank.to_string()),
                goal: s.goal.clone(),
                tags: s.tags.clone(),
                depends_on: s.depends_on.clone(),
                branch: s.branch.clone(),
            }
        }).collect();
        println!("{}", serde_json::to_string_pretty(&entries)?);
        return Ok(());
    }

    // Text output — group sessions
    let mut grouped: std::collections::BTreeMap<String, Vec<&crate::registry::WorkspaceSession>> = std::collections::BTreeMap::new();
    for s in &sessions {
        let gname = s.group.as_ref()
            .map(|g| g.name.clone())
            .unwrap_or_else(|| "ungrouped".to_string());
        grouped.entry(gname).or_default().push(s);
    }

    // Sort within each group: rank then name
    for sessions in grouped.values_mut() {
        sessions.sort_by(|a, b| {
            let ra = a.group.as_ref().map(|g| &g.rank);
            let rb = b.group.as_ref().map(|g| &g.rank);
            match (ra, rb) {
                (Some(crate::registry::GroupRank::Number(na)), Some(crate::registry::GroupRank::Number(nb))) => na.cmp(nb),
                (Some(crate::registry::GroupRank::Number(_)), Some(crate::registry::GroupRank::Free)) => std::cmp::Ordering::Greater,
                (Some(crate::registry::GroupRank::Free), Some(crate::registry::GroupRank::Number(_))) => std::cmp::Ordering::Less,
                _ => a.name.cmp(&b.name),
            }
        });
    }

    // Sort groups: "ungrouped" last, others alphabetical
    let mut group_names: Vec<String> = grouped.keys().cloned().collect();
    group_names.sort_by(|a, b| {
        match (a == "ungrouped", b == "ungrouped") {
            (true, true) => std::cmp::Ordering::Equal,
            (true, false) => std::cmp::Ordering::Greater,
            (false, true) => std::cmp::Ordering::Less,
            (false, false) => a.cmp(b),
        }
    });

    let mut first_group = true;
    for gname in &group_names {
        let members = &grouped[gname];
        if !first_group {
            println!();
        }
        first_group = false;
        println!("#group:{}", gname);
        for s in members {
            let icon = status_icon(&s.status);
            let goal = truncate_for_scan(&s.goal, 65);
            let tags_str = if s.tags.is_empty() {
                String::new()
            } else {
                format!("  {}", s.tags.join(","))
            };
            println!("{}  {:<28}  {}{}", icon, s.name, goal, tags_str);
        }
    }

    Ok(())
}

/// Truncate for scan output — shorter than the markdown table version.
fn truncate_for_scan(s: &str, max_len: usize) -> String {
    let one_line = s.replace('\n', " ").replace('|', "\\|");
    if one_line.len() > max_len {
        format!("{}...", &one_line[..max_len.saturating_sub(3)])
    } else {
        one_line
    }
}

/// `ccsm list` — all sessions, one line each.  --active / --summary / --status filter / --verbose / --group / --by-rank / --json.
fn run_list(active: bool, summary: bool, verbose: bool, status_filter: Option<&str>, group_filter: Option<&str>, by_rank: bool, json: bool) -> anyhow::Result<()> {
    use crate::registry::SessionStatus;
    let reg = load_workspace_registry()?;

    let filter: Option<SessionStatus> = match status_filter {
        Some("pending") => Some(SessionStatus::Pending),
        Some("in_progress") | Some("in-progress") => Some(SessionStatus::InProgress),
        Some("completed") => Some(SessionStatus::Completed),
        Some("blocked") => Some(SessionStatus::Blocked),
        Some("abandoned") => Some(SessionStatus::Abandoned),
        Some("trashed") => Some(SessionStatus::Trashed),
        Some(other) => {
            eprintln!("{} unknown status '{}'", ErrorCode::BadStatus, other);
            eprintln!();
            eprintln!("Valid statuses:");
            eprintln!("  pending      — planned, not started yet");
            eprintln!("  in_progress  — actively working on (max 1 per workspace)");
            eprintln!("  completed    — finished successfully");
            eprintln!("  blocked      — can't proceed, waiting on a dependency");
            eprintln!("  abandoned    — gave up, no longer relevant");
            eprintln!("  trashed      — soft-deleted, recoverable with `ccsm recover <name>`");
            return Ok(());
        }
        None => None,
    };

    let use_json = json || output_format_json();

    // Summary mode: counts only (text)
    if summary && !use_json {
        let mut counts = std::collections::BTreeMap::new();
        for s in &reg.sessions {
            if active && !matches!(s.status, SessionStatus::InProgress | SessionStatus::Blocked) {
                continue;
            }
            if let Some(fs) = filter
                && s.status != fs { continue; }
            if let Some(g) = group_filter
                && !s.group.as_ref().is_some_and(|grp| grp.name == g) { continue; }
            *counts.entry(s.status).or_insert(0) += 1;
        }
        let total: usize = counts.values().sum();
        let get = |s: SessionStatus| counts.get(&s).copied().unwrap_or(0);
        println!(
            "{} active | {} pending | {} completed | {} blocked | {} abandoned | {} trashed | {} total",
            get(SessionStatus::InProgress),
            get(SessionStatus::Pending),
            get(SessionStatus::Completed),
            get(SessionStatus::Blocked),
            get(SessionStatus::Abandoned),
            get(SessionStatus::Trashed),
            total,
        );
        return Ok(());
    }

    // JSON output (session list or summary)
    if use_json && summary {
        let mut counts = std::collections::BTreeMap::new();
        for s in &reg.sessions {
            if active && !matches!(s.status, SessionStatus::InProgress | SessionStatus::Blocked) {
                continue;
            }
            if let Some(fs) = filter && s.status != fs { continue; }
            if let Some(g) = group_filter && !s.group.as_ref().is_some_and(|grp| grp.name == g) { continue; }
            *counts.entry(s.status).or_insert(0) += 1;
        }
        let total: usize = counts.values().sum();
        let get = |s: SessionStatus| counts.get(&s).copied().unwrap_or(0);
        let summary_json = serde_json::json!({
            "active": get(SessionStatus::InProgress),
            "pending": get(SessionStatus::Pending),
            "completed": get(SessionStatus::Completed),
            "blocked": get(SessionStatus::Blocked),
            "abandoned": get(SessionStatus::Abandoned),
            "trashed": get(SessionStatus::Trashed),
            "total": total,
        });
        println!("{}", serde_json::to_string_pretty(&summary_json)?);
        return Ok(());
    }

    // JSON list output
    if use_json {
        #[derive(serde::Serialize)]
        struct ListEntry {
            name: String,
            status: String,
            goal: String,
            scope: String,
            tags: Vec<String>,
            group: Option<String>,
            rank: Option<String>,
            session_id: String,
            started: String,
            completed: String,
            depends_on: Vec<String>,
            consumer: String,
            branch: String,
        }
        let entries: Vec<ListEntry> = reg.sessions.iter()
            .filter(|s| {
                if active && !matches!(s.status, SessionStatus::InProgress | SessionStatus::Blocked) { return false; }
                if let Some(fs) = filter && s.status != fs { return false; }
                if let Some(g) = group_filter && !s.group.as_ref().is_some_and(|grp| grp.name == g) { return false; }
                true
            })
            .map(|s| ListEntry {
                name: s.name.clone(),
                status: s.status.to_string(),
                goal: s.goal.clone(),
                scope: s.scope.clone(),
                tags: s.tags.clone(),
                group: s.group.as_ref().map(|g| g.name.clone()),
                rank: s.group.as_ref().map(|g| g.rank.to_string()),
                session_id: s.session_id.clone(),
                started: s.started.clone(),
                completed: s.completed.clone(),
                depends_on: s.depends_on.clone(),
                consumer: s.consumer.clone(),
                branch: s.branch.clone(),
            })
            .collect();
        if entries.is_empty() {
            println!("[]");
        } else {
            println!("{}", serde_json::to_string_pretty(&entries)?);
        }
        return Ok(());
    }

    // List mode
    if reg.sessions.is_empty() {
        println!("(no sessions)");
        return Ok(());
    }

    // Collect and optionally sort by rank
    let mut sessions: Vec<&crate::registry::WorkspaceSession> = reg.sessions.iter().collect();
    if by_rank && group_filter.is_some() {
        let g = group_filter.unwrap();
        sessions.retain(|s| s.group.as_ref().is_some_and(|grp| grp.name == g));
        sessions.sort_by(|a, b| {
            let ra = a.group.as_ref().map(|grp| &grp.rank);
            let rb = b.group.as_ref().map(|grp| &grp.rank);
            match (ra, rb) {
                (Some(crate::registry::GroupRank::Number(na)), Some(crate::registry::GroupRank::Number(nb))) => na.cmp(nb),
                (Some(crate::registry::GroupRank::Number(_)), Some(crate::registry::GroupRank::Free)) => std::cmp::Ordering::Greater,
                (Some(crate::registry::GroupRank::Free), Some(crate::registry::GroupRank::Number(_))) => std::cmp::Ordering::Less,
                _ => a.name.cmp(&b.name),
            }
        });
    }

    let mut printed = 0;
    for s in &sessions {
        if active && !matches!(s.status, SessionStatus::InProgress | SessionStatus::Blocked) {
            continue;
        }
        if let Some(fs) = filter
            && s.status != fs { continue; }
        if let Some(g) = group_filter
            && !s.group.as_ref().is_some_and(|grp| grp.name == g) {
                continue;
            }
        let group_tag = s.group.as_ref().map(|grp| format!(" [{}:{}]", grp.name, grp.rank)).unwrap_or_default();
        if verbose {
            // Teammate scan mode: full goal + tags, one line per session
            let goal = if s.goal.is_empty() { "" } else { " — " };
            let tags = if s.tags.is_empty() {
                String::new()
            } else {
                format!("  [{}]", s.tags.join(", "))
            };
            println!("{:12}  {:30}  {}{}{}{}", s.status.to_string(), s.name, goal, s.goal, tags, group_tag);
        } else {
            let goal = if s.goal.is_empty() { "" } else { " — " };
            let goal_text = if s.goal.len() > 80 {
                format!("{}{:.77}...", goal, &s.goal)
            } else {
                format!("{}{}", goal, &s.goal)
            };
            println!("{:12}  {:30}  {}{}", s.status.to_string(), s.name, goal_text.trim(), group_tag);
        }
        printed += 1;
    }
    if printed == 0 {
        println!("(no matching sessions)");
    }
    Ok(())
}

// ── Mutations (shared helpers) ─────────────────────────────────────────

/// Load the registry, mutate one session by name, save, and report.
fn mutate_session<F>(name: &str, action: &str, f: F) -> anyhow::Result<()>
where
    F: FnOnce(&mut crate::registry::WorkspaceSession),
{
    use crate::registry::SessionStatus;
    let (mut reg, _lock) = crate::registry::WorkspaceRegistry::load_locked()?;
    {
        let entry = reg
            .sessions
            .iter_mut()
            .find(|s| s.name == name)
            .ok_or_else(|| anyhow::anyhow!("{} no session named '{}'", ErrorCode::NoSession, name))?;
        let old_status = entry.status;
        f(entry);
        if entry.status != old_status
            && !SessionStatus::transition_allowed(old_status, entry.status)
        {
            anyhow::bail!(
                "{} cannot transition session '{}' from {} to {}",
                ErrorCode::BadStatus,
                name,
                old_status,
                entry.status,
            );
        }
    }
    reg.updated = crate::registry::now_iso();
    reg.save()?;
    // Re-borrow immutably for the status line
    let entry = reg.sessions.iter().find(|s| s.name == name).unwrap();
    action_msg(&entry.status.to_string(), &entry.name, action);
    Ok(())
}

// ── Mutation commands ───────────────────────────────────────────────────

/// `ccsm attach <name> [session-id] [--pid <pid>]` — link a Claude session_id to an entry.
///
/// If neither session-id nor --pid is given, auto-discovers the most recently
/// updated live Claude session in this workspace.
fn run_attach(name: &str, session_id: Option<&str>, pid: Option<u32>, home: &std::path::Path, consumer: Consumer) -> anyhow::Result<()> {
    let workspace = std::env::current_dir()?;

    let resolved_sid = match (session_id.filter(|s| !s.is_empty()), pid) {
        (Some(sid), _) => {
            crate::registry::validate_session_id(sid)?;
            sid.to_string()
        }
        (_, Some(p)) if consumer.is_claude() => crate::registry::harvest_from_pid(home, p)?,
        (_, Some(_p)) => anyhow::bail!(
            "--pid is not supported for {consumer}. Provide the session UUID directly."
        ),
        _ => {
            // Auto-discover
            match consumer {
                Consumer::Claude => {
                    let sessions = crate::session::load_all(
                        &consumer.sessions_dir(home),
                        Some(&workspace),
                    )?;
                    match sessions.as_slice() {
                        [] => anyhow::bail!(
                            "no live {} sessions found in this workspace.\n\
                             Is {} running? Start it first, then `ccsm attach {}`.",
                            consumer, consumer.binary(), name,
                        ),
                        [s] => {
                            if s.session_id.is_empty() {
                                anyhow::bail!(
                                    "session file for PID {} has no sessionId yet — wait for {} to finish starting",
                                    s.pid, consumer.binary(),
                                );
                            }
                            eprintln!("auto-detected PID {} ({})", s.pid, s.display_name());
                            s.session_id.clone()
                        }
                        multiple => {
                            let by_name: Vec<_> = multiple
                                .iter()
                                .filter(|s| s.name == name)
                                .collect();
                            match by_name.as_slice() {
                                [s] => {
                                    eprintln!("auto-detected PID {} (name match: {})", s.pid, s.display_name());
                                    s.session_id.clone()
                                }
                                [] => {
                                    eprintln!("multiple live sessions in this workspace (none named '{}'):", name);
                                    for s in multiple {
                                        eprintln!(
                                            "  pid {}  {:16}  {}  {}",
                                            s.pid,
                                            s.display_name(),
                                            s.status,
                                            &s.session_id[..s.session_id.len().min(8)],
                                        );
                                    }
                                    anyhow::bail!("pick one with --pid <pid>.");
                                }
                                _ => {
                                    eprintln!("multiple sessions named '{}' — picking most recent:", name);
                                    let s = &by_name[0];
                                    eprintln!("  pid {}  {}  {}", s.pid, s.status, &s.session_id[..s.session_id.len().min(8)]);
                                    s.session_id.clone()
                                }
                            }
                        }
                    }
                }
                Consumer::Pi => {
                    // Pi: find the most recently modified JSONL session file
                    let slug = consumer.project_slug(&workspace);
                    let dir = consumer.projects_dir(home, &slug);
                    if !dir.is_dir() {
                        anyhow::bail!(
                            "no Pi sessions found in this workspace.\n\
                             Start pi first, then `ccsm attach {}`.",
                            name
                        );
                    }
                    let mut candidates: Vec<_> = std::fs::read_dir(&dir)
                        .into_iter()
                        .flatten()
                        .filter_map(|e| {
                            let p = e.ok()?.path();
                            if p.extension().is_some_and(|ext| ext == "jsonl") {
                                let mtime = std::fs::metadata(&p).ok()?.modified().ok()?;
                                Some((mtime, p))
                            } else {
                                None
                            }
                        })
                        .collect();
                    candidates.sort_by(|a, b| b.0.cmp(&a.0)); // most recent first
                    if candidates.is_empty() {
                        anyhow::bail!(
                            "no Pi session files found in this workspace.\n\
                             Start pi first, then `ccsm attach {}`.",
                            name
                        );
                    }
                    let latest = &candidates[0].1;
                    let meta = crate::consumer::read_pi_session_meta(latest)?;
                    if meta.session_id.is_empty() {
                        anyhow::bail!("could not extract session ID from {}", latest.display());
                    }
                    eprintln!("auto-detected session {} from {}", &meta.session_id[..8], latest.display());
                    meta.session_id
                }
                Consumer::OpenCode => {
                    // OpenCode: query SQLite for the most recent session in this workspace
                    let db_path = crate::consumer::opencode_db_path(home);
                    if !db_path.exists() {
                        anyhow::bail!(
                            "no opencode DB found at {}. Start opencode first, then `ccsm attach {}`.",
                            db_path.display(), name
                        );
                    }
                    match crate::consumer::opencode_latest_session(&db_path, &workspace.to_string_lossy()) {
                        Some(sid) => {
                            eprintln!("auto-detected session {} from opencode DB", &sid[..sid.len().min(8)]);
                            sid
                        }
                        None => anyhow::bail!(
                            "no opencode sessions found in this workspace.\n\
                             Start opencode first, then `ccsm attach {}`.",
                            name
                        ),
                    }
                }
            }
        }
    };

    // Verify session file exists
    let found = consumer.find_session_file_for(home, &workspace, &resolved_sid);
    if found.is_none() {
        eprintln!(
            "warning: session file not found for {} in {} workspace.\n  The session_id may be from a different workspace.",
            &resolved_sid[..resolved_sid.len().min(8)],
            consumer,
        );
    }

    let (mut reg, _lock) = crate::registry::WorkspaceRegistry::load_locked()?;
    let entry = reg
        .sessions
        .iter_mut()
        .rev()
        .find(|s| s.name == name)
        .ok_or_else(|| anyhow::anyhow!("{} no session named '{}'", ErrorCode::NoSession, name))?;
    entry.session_id = resolved_sid.clone();
    reg.updated = crate::registry::now_iso();
    reg.save()?;
    action_msg("attached", name, &format!("session {}", &resolved_sid[..resolved_sid.len().min(8)]));
    Ok(())
}

/// `ccsm rename <old> <new>` — rename a session across registry, detail file,
/// live session files, group files, and transcript.
fn run_rename(old: &str, new: &str, goal: Option<&str>, scope: Option<&str>, home: &std::path::Path, workspace: &std::path::Path, consumer: Consumer) -> anyhow::Result<()> {
    // ── Phase 1: Validate + snapshot under lock, then release for slow I/O ──
    let (sid, old_goal, old_scope, old_group) = {
        let (reg, _lock) = crate::registry::WorkspaceRegistry::load_locked()?;

        let idx = reg
            .sessions
            .iter()
            .position(|s| s.name == old)
            .ok_or_else(|| anyhow::anyhow!("no session named '{}'", old))?;
        if reg.sessions.iter().any(|s| s.name == new) {
            anyhow::bail!("{} session '{}' already exists", ErrorCode::Exists, new);
        }
        if !crate::registry::is_kebab_case(new) {
            anyhow::bail!(
                "'{}' is not kebab-case. Session names must be lowercase letters, digits, and hyphens.",
                new
            );
        }

        let sid = reg.sessions[idx].session_id.clone();
        let old_goal = reg.sessions[idx].goal.clone();
        let old_scope = reg.sessions[idx].scope.clone();
        let old_group = reg.sessions[idx].group.clone();

        (sid, old_goal, old_scope, old_group)
    }; // Lock released here — Phase 2 I/O doesn't hold it

    // ── Phase 2: I/O-heavy operations (no lock held) ──

    // 1. Update session name in transcript (consumer-specific)
    if !sid.is_empty() {
        if consumer.is_opencode() {
            let db_path = crate::consumer::opencode_db_path(home);
            if db_path.exists() {
                match crate::consumer::opencode_update_title(&db_path, &sid, new) {
                    Ok(_) => eprintln!("  opencode DB  title '{}' → '{}'", old, new),
                    Err(e) => eprintln!("  opencode DB  failed to update title: {e}"),
                }
            }
        } else if let Some(transcript) = consumer.find_session_file_for(home, workspace, &sid) {
            let rename_line = format!(
                "{{\"type\":\"custom-title\",\"customTitle\":\"{}\",\"sessionId\":\"{}\"}}\n\
                 {{\"type\":\"agent-name\",\"agentName\":\"{}\",\"sessionId\":\"{}\"}}\n",
                new, sid, new, sid
            );
            use std::io::Write;
            let mut file = std::fs::OpenOptions::new()
                .append(true)
                .open(&transcript)
                .with_context(|| format!("opening transcript for append: {}", transcript.display()))?;
            file.write_all(rename_line.as_bytes())
                .with_context(|| format!("appending rename to transcript: {}", transcript.display()))?;
            file.flush()
                .with_context(|| format!("flushing transcript: {}", transcript.display()))?;
            eprintln!("  transcript  appended custom-title + agent-name: {}", new);
        } else {
            eprintln!(
                "  transcript  not found — session may not have been spawned yet (skipping)"
            );
        }
    }

    // 2. Update live session files (best-effort, ephemeral) — use proper serde
    let sessions_dir = consumer.sessions_dir(home);
    if let Ok(entries) = std::fs::read_dir(&sessions_dir) {
        for entry in entries.flatten() {
            let path = entry.path();
            if path.extension().is_none_or(|e| e != "json") {
                continue;
            }
            let Ok(contents) = std::fs::read_to_string(&path) else { continue };
            if let Ok(session) = serde_json::from_str::<crate::session::Session>(&contents) {
                let ws = workspace.to_string_lossy().to_string();
                if session.name == old && session.cwd.starts_with(&ws) {
                    if let Ok(mut value) = serde_json::from_str::<serde_json::Value>(&contents) {
                        if let Some(obj) = value.as_object_mut() {
                            obj.insert("name".to_string(), serde_json::Value::String(new.to_string()));
                        }
                        let updated = serde_json::to_string(&value);
                        if let Ok(json) = updated {
                            let _ = std::fs::write(&path, json);
                            eprintln!("  session file  pid {}  name → {}", session.pid, new);
                        }
                    }
                }
            }
        }
    }

    // 3. Rename detail file
    let ctx = crate::registry::resolve_or_create_identity()?;
    let detail_old = crate::registry::global_detail_path(&ctx.id, old);
    let detail_new = crate::registry::global_detail_path(&ctx.id, new);
    if detail_old.exists() {
        std::fs::rename(&detail_old, &detail_new).with_context(|| {
            format!(
                "renaming detail file: {} → {}",
                detail_old.display(),
                detail_new.display()
            )
        })?;
        eprintln!("  detail file  {}.md → {}.md", old, new);
    }

    // ── Phase 3: Re-acquire lock for registry mutation ──
    let (mut reg, _lock) = crate::registry::WorkspaceRegistry::load_locked()?;

    // Re-validate: old must still exist (another ccsm could have removed it)
    let idx = reg
        .sessions
        .iter()
        .position(|s| s.name == old)
        .ok_or_else(|| anyhow::anyhow!("session '{}' was removed before rename completed", old))?;
    if reg.sessions.iter().any(|s| s.name == new) {
        anyhow::bail!("{} session '{}' was created before rename completed", ErrorCode::Exists, new);
    }

    let has_topic_change = goal.is_some() || scope.is_some();

    // 4. Update detail file content — replace header, goal, scope
    if detail_new.exists()
        && let Ok(contents) = std::fs::read_to_string(&detail_new) {
            let mut updated = contents
                .replace(&format!("# Session: {}", old), &format!("# Session: {}", new));
            if let Some(g) = goal {
                updated = crate::registry::replace_detail_section(&updated, "## Goal", g);
            }
            if let Some(s) = scope {
                updated = crate::registry::replace_detail_section(&updated, "## Scope / Plan", s);
            }
            let _ = std::fs::write(&detail_new, &updated);
            eprintln!("  detail file  updated header");
        }

    // 5. Update dependency cross-references — every session that depended_on
    //    the old name now references the new name
    let mut deps_updated = Vec::new();
    for s in &mut reg.sessions {
        for dep in &mut s.depends_on {
            if dep == old {
                *dep = new.to_string();
                if !deps_updated.contains(&s.name) {
                    deps_updated.push(s.name.clone());
                }
            }
        }
    }
    // Sync updated cross-references to each affected session's detail file
    for name in &deps_updated {
        if let Some(s) = reg.sessions.iter().find(|s| s.name == *name) {
            let _ = update_deps_in_detail(name, &s.depends_on);
        }
    }

    // 6. Update registry entry
    reg.sessions[idx].name = new.to_string();
    if let Some(g) = goal {
        reg.sessions[idx].goal = g.to_string();
    }
    if let Some(s) = scope {
        reg.sessions[idx].scope = s.to_string();
    }
    reg.updated = crate::registry::now_iso();
    reg.save()?;

    // 7. Update group detail file if session belongs to a group
    if let Some(ref g) = old_group {
        ensure_group_file(&g.name, &reg)?;
        eprintln!("  group file  {} updated ({} → {})", g.name, old, new);
    }

    drop(_lock); // Release before progress log I/O

    // 8. Log the rename to progress log (include old values and dep updates)
    if detail_new.exists() {
        let ts = crate::registry::note_timestamp();
        let mut note_parts = vec![format!("Renamed from '{}' to '{}'", old, new)];
        if has_topic_change {
            note_parts.push(format!("Old goal: {}", old_goal));
            if !old_scope.is_empty() {
                note_parts.push(format!("Old scope: {}", old_scope));
            }
        }
        if !deps_updated.is_empty() {
            let affected = deps_updated.join(", ");
            note_parts.push(format!("Updated dependency cross-references: {}", affected));
        }
        let note_line = format!("- [{}] {}\n", ts, note_parts.join(" | "));
        if let Ok(contents) = std::fs::read_to_string(&detail_new) {
            let updated = crate::registry::insert_note(&contents, &note_line);
            let _ = std::fs::write(&detail_new, updated);
        }
    }

    action_msg("renamed", old, &format!("→ {}", new));
    Ok(())
}

/// `ccsm trash <name>` — soft-delete: move to Trashed status.
fn run_trash(name: &str) -> anyhow::Result<()> {
    let (mut reg, _lock) = crate::registry::WorkspaceRegistry::load_locked()?;
    // Get session_id for the entry (may be empty for seed entries).
    let sid = reg.sessions.iter().rev()
        .find(|s| s.name == name)
        .map(|s| s.session_id.clone())
        .unwrap_or_default();
    if reg.trash(&sid, name) {
        reg.updated = crate::registry::now_iso();
        reg.save()?;
        action_msg("trashed", name, &format!("soft-deleted (recover with `ccsm recover {}`)", name));
    } else {
        anyhow::bail!("{} no session named '{}'", ErrorCode::NoSession, name);
    }
    Ok(())
}

/// `ccsm recover <name>` — untrash: move from Trashed → InProgress.
fn run_recover(name: &str) -> anyhow::Result<()> {
    let (mut reg, _lock) = crate::registry::WorkspaceRegistry::load_locked()?;

    // Validate: only trashed sessions can be recovered
    let (sid, status) = {
        let entry = reg.sessions.iter().rev()
            .find(|s| s.name == name)
            .ok_or_else(|| anyhow::anyhow!("{} no session named '{}'", ErrorCode::NoSession, name))?;
        (entry.session_id.clone(), entry.status)
    };
    if !crate::registry::SessionStatus::transition_allowed(status, crate::registry::SessionStatus::InProgress) {
        anyhow::bail!(
            "{} cannot recover session '{}' from {}",
            ErrorCode::BadStatus, name, status
        );
    }
    if reg.recover(&sid, name) {
        reg.updated = crate::registry::now_iso();
        reg.save()?;
        action_msg("recovered", name, "in_progress");
    } else {
        anyhow::bail!("{} no session named '{}'", ErrorCode::NoSession, name);
    }
    Ok(())
}

/// `ccsm clean <name>` — permanently delete transcript, session files, and registry entry.
fn run_clean(name: &str, home: &std::path::Path, workspace: &std::path::Path, consumer: Consumer) -> anyhow::Result<()> {
    // Best-effort worktree removal before permanent delete (no lock)
    let _ = commands::worktree::remove_worktree(workspace, name, true);

    let (mut reg, _lock) = crate::registry::WorkspaceRegistry::load_locked()?;
    let sid = reg.sessions.iter().rev()
        .find(|s| s.name == name)
        .map(|s| s.session_id.clone())
        .unwrap_or_default();
    // Check entry exists before deleting
    if !reg.sessions.iter().any(|s| s.name == name) {
        anyhow::bail!("{} no session named '{}'", ErrorCode::NoSession, name);
    }
    reg.clean(&sid, name, home, workspace, consumer);
    reg.updated = crate::registry::now_iso();
    reg.save()?;
    action_msg("cleaned", name, "permanently deleted");
    Ok(())
}

/// `ccsm clean-all` — permanently delete ALL trashed entries.
fn run_clean_all(home: &std::path::Path, workspace: &std::path::Path, consumer: Consumer) -> anyhow::Result<()> {
    let (mut reg, _lock) = crate::registry::WorkspaceRegistry::load_locked()?;
    let count = reg.sessions.iter()
        .filter(|s| s.status == crate::registry::SessionStatus::Trashed)
        .count();
    if count == 0 {
        println!("(no trashed sessions)");
        return Ok(());
    }
    reg.clean_all_trashed(home, workspace, consumer);
    reg.updated = crate::registry::now_iso();
    reg.save()?;
    action_msg("cleaned", &format!("{} trashed", count), "permanently deleted");
    Ok(())
}

/// `ccsm archive <name>` — delete transcript + session files, keep registry entry.
fn run_archive(name: &str, home: &std::path::Path, workspace: &std::path::Path, consumer: Consumer) -> anyhow::Result<()> {
    let (mut reg, _lock) = crate::registry::WorkspaceRegistry::load_locked()?;
    let sid = reg.sessions.iter().rev()
        .find(|s| s.name == name)
        .map(|s| s.session_id.clone())
        .unwrap_or_default();

    if !reg.sessions.iter().any(|s| s.name == name) {
        anyhow::bail!("{} no session named '{}'", ErrorCode::NoSession, name);
    }

    // Check not active
    if let Some(s) = reg.sessions.iter().find(|s| s.name == name)
        && s.status == crate::registry::SessionStatus::InProgress {
            anyhow::bail!(
                "cannot archive active session '{}'. Complete or abandon it first.",
                name
            );
        }

    let freed = reg.archive(&sid, name, home, workspace, consumer);
    reg.updated = crate::registry::now_iso();
    reg.save()?;

    if freed > 0 {
        action_msg("archived", name, &format!("freed {} MB", freed / 1_000_000));
    } else {
        action_msg("archived", name, "already archived (no transcript)");
    }
    Ok(())
}

/// `ccsm archive-all` — archive all completed sessions with transcripts.
fn run_archive_all(home: &std::path::Path, workspace: &std::path::Path, consumer: Consumer) -> anyhow::Result<()> {
    let (mut reg, _lock) = crate::registry::WorkspaceRegistry::load_locked()?;
    let candidates: Vec<(String, String)> = reg
        .sessions
        .iter()
        .filter(|s| s.status == crate::registry::SessionStatus::Completed && !s.session_id.is_empty())
        .map(|s| (s.session_id.clone(), s.name.clone()))
        .collect();

    if candidates.is_empty() {
        println!("(no completed sessions with transcripts to archive)");
        return Ok(());
    }

    let mut total_freed: u64 = 0;
    for (sid, name) in &candidates {
        total_freed += reg.archive(sid, name, home, workspace, consumer);
    }
    reg.updated = crate::registry::now_iso();
    reg.save()?;

    println!(
        "archived    {} session{}  ← freed {} MB",
        candidates.len(),
        if candidates.len() == 1 { "" } else { "s" },
        total_freed / 1_000_000,
    );
    Ok(())
}

/// `ccsm new <name> [goal]` — create a new session entry.
fn run_new(name: &str, goal: &str, force: bool, checklist: Option<String>, branch: &str, worktree: bool, consumer: Consumer) -> anyhow::Result<()> {
    let ctx = crate::registry::resolve_or_create_identity()?;
    let config = crate::config::Config::load();

    // ── Config enforcement: branch required ──────────────────────────
    use crate::config::BranchTracking;
    if config.branch_tracking == BranchTracking::Required && branch.is_empty() {
        let config_path = crate::registry::global_config_path(&ctx.id);
        anyhow::bail!(
            "\n⚠️  This project requires branch tracking (branch_tracking=required in {}).\n\
             Use `ccsm new {} -b <branch> -g \"...\"` to set a target branch.",
            config_path.display(),
            name
        );
    }

    // ── Kebab-case validation ──────────────────────────────────────────
    if !crate::registry::is_kebab_case(name) {
        anyhow::bail!(
            "{} session name '{}' must be kebab-case (lowercase, digits, hyphens only)",
            ErrorCode::Invalid,
            name,
        );
    }

    let (mut reg, _lock) = crate::registry::WorkspaceRegistry::load_locked()?;

    // ── WIP guard ─────────────────────────────────────────────────────
    if config.wip_limit > 0 {
        let active_count = reg.sessions.iter()
            .filter(|s| s.status == crate::registry::SessionStatus::InProgress)
            .count();
        if active_count >= config.wip_limit {
            eprintln!(
                "⚠️  {} sessions already in_progress (limit: {}). Consider finishing those first.",
                active_count, config.wip_limit
            );
        }
    }

    // Exact duplicate
    if reg.sessions.iter().any(|s| s.name == name) {
        anyhow::bail!("{} session '{}' already exists", ErrorCode::Exists, name);
    }

    // Fuzzy duplicate — catch typos before creating garbage (skip with --force)
    if !force {
        let similar: Vec<&str> = reg
            .sessions
            .iter()
            .map(|s| s.name.as_str())
            .filter(|n| {
                // Substring: only flag if the overlap is significant (≥40% of longer name)
                let shorter = n.len().min(name.len());
                let longer = n.len().max(name.len());
                let significant_overlap = shorter >= 4 && (shorter as f64 / longer as f64) >= 0.4;
                (significant_overlap && (n.contains(name) || name.contains(*n)))
                    || (name.len() >= 4 && crate::registry::edit_distance(n, name) <= 2)
                    || crate::registry::edit_distance(n, name) <= 1
            })
            .take(3)
            .collect();
        if !similar.is_empty() {
            anyhow::bail!(
                "session '{}' looks similar to existing: {}. Use --force to create anyway, or `ccsm resume <name>` to continue an existing session.",
                name,
                similar.join(", "),
            );
        }
    }

    reg.sessions.push(crate::registry::WorkspaceSession {
        session_id: String::new(),
        name: name.to_string(),
        goal: goal.to_string(),
        scope: String::new(),
        status: crate::registry::SessionStatus::Pending,
        pids: vec![],
        tags: vec![],
        started: String::new(),
        completed: String::new(),
        group: None,
        depends_on: vec![],
        branch: branch.to_string(),
        use_worktree: worktree,
        retired_session_ids: vec![],
        consumer: consumer.to_string(),
    });
    reg.updated = crate::registry::now_iso();
    reg.save()?;

    // Auto-create the detail file from template if it doesn't exist.
    let detail_path = crate::registry::global_detail_path(&ctx.id, name);
    if !detail_path.exists() {
        let template_path = crate::registry::global_template_path(&ctx.id);
        // Auto-create the template if it's missing
        if !template_path.exists() {
            let _ = std::fs::write(&template_path, crate::commands::doctor::TEMPLATE_CONTENT);
        }
        if template_path.exists()
            && let Ok(contents) = std::fs::read_to_string(&template_path) {
                let populated = contents
                    .replace("{{name}}", name)
                    .replace("{{goal}}", goal)
                    .replace("{{status}}", "pending")
                    .replace("{{scope}}", "(fill in — approach, constraints, what's in/out)")
                    .replace("{{tags}}", "(fill in)")
                    .replace("{{pid_count}}", "0")
                    .replace("{{started}}", "")
                    .replace("{{completed}}", "")
                    .replace("{{dependencies}}", "(none)")
                    .replace("{{now}}", &crate::registry::now_iso())
                    .replace("{{note}}", "Session created");
                if let Some(parent) = detail_path.parent() {
                    let _ = std::fs::create_dir_all(parent);
                }
                let _ = std::fs::write(&detail_path, populated);
                // ── Checklist section ─────────────────────────────────
                if checklist.is_some() || config.default_checklist_type.is_some() {
                    let template_type = checklist.as_deref()
                        .or(config.default_checklist_type.as_deref());
                    let checklist_content = build_checklist_section(name, template_type, &config);
                    let _ = std::fs::write(&detail_path, std::fs::read_to_string(&detail_path).unwrap_or_default() + &checklist_content);
                }
            }
    }

    action_msg("pending", name, "created");
    Ok(())
}

/// Build a ## Checklist section with optional template items.
fn build_checklist_section(_name: &str, template_type: Option<&str>, config: &crate::config::Config) -> String {
    let header = "\n## Checklist\n\n<!--\n  All items must be resolved before close gate allows completion.\n  Status: pending | done | skipped | blocked\n  Checkbox chars: - [ ] pending, - [x] done, - [~] skipped, - [!] blocked\n-->\n";

    let items = match template_type {
        Some(typ) => config.get_checklist_items(typ),
        None => None,
    };

    match items {
        Some(item_list) if !item_list.is_empty() => {
            let mut body = String::from(header);
            for item in &item_list {
                body.push_str(&format!("- [ ] {}\n", item));
            }
            body
        }
        _ => {
            // Empty checklist — users populate via `ccsm check`
            format!(
                "{}(no items yet — use `ccsm check <name> \"<text>\" -s pending` to add one)\n",
                header
            )
        }
    }
}

/// Determine whether a session should get a worktree, based on config policy + session flags.
fn should_use_worktree(session: &crate::registry::WorkspaceSession, config: &crate::config::Config) -> bool {
    use crate::config::WorktreePolicy;
    match config.worktrees {
        WorktreePolicy::Required => !session.branch.is_empty(),
        WorktreePolicy::Optional => session.use_worktree && !session.branch.is_empty(),
        WorktreePolicy::Disabled => false,
    }
}

/// `ccsm start <name> [--worktree]` — promote to InProgress, create worktree if applicable.
fn run_start(name: &str, flag_worktree: bool) -> anyhow::Result<()> {
    use crate::registry::SessionStatus;
    let workspace = workspace_path();
    let config = crate::config::Config::load();

    // Phase 1: Load registry, validate, read branch (locked)
    let (branch, use_wt) = {
        let (reg, _lock) = crate::registry::WorkspaceRegistry::load_locked()?;
        let entry = reg
            .sessions
            .iter()
            .find(|s| s.name == name)
            .ok_or_else(|| anyhow::anyhow!("{} no session named '{}'", ErrorCode::NoSession, name))?;

        anyhow::ensure!(
            entry.status == SessionStatus::Pending,
            "{} session '{}' is {} — only pending sessions can be started",
            ErrorCode::BadStatus, name, entry.status
        );

        let use_wt = flag_worktree || should_use_worktree(entry, &config);
        if use_wt {
            anyhow::ensure!(
                !entry.branch.is_empty(),
                "session '{}' has no target branch. Use `ccsm new {} -b <branch> -g \"...\"` to set one.",
                name, name
            );
            anyhow::ensure!(
                !commands::worktree::worktree_path_for(&workspace, name).exists(),
                "worktree for session '{}' already exists. Use `ccsm resume {}` to continue, or `ccsm worktree remove {}` to clean up.",
                name, name, name
            );
        }

        (entry.branch.clone(), use_wt)
    }; // lock released

    // Phase 2: Create worktree if configured (no lock — git operation)
    let wt_path = if use_wt {
        let wt = commands::worktree::create_worktree(&workspace, name, &branch)
            .map_err(|e| {
                eprintln!("warning: worktree creation failed — continuing without worktree");
                e
            })
            .ok();
        wt
    } else {
        None
    };

    // Phase 3: Status transition (locked)
    mutate_session(name, "start", |entry| {
        entry.status = SessionStatus::InProgress;
        if flag_worktree {
            entry.use_worktree = true;
        }
    })?;

    crate::registry::sync_status_line(name);

    if let Some(ref path) = wt_path {
        println!("📁 worktree: {}", path.display());
    }
    eprintln!("💡 multi-step? `ccsm checklist {} --init` to add sub-task tracking", name);

    Ok(())
}

/// `ccsm complete <name> [--force]` — promote to Completed, remove worktree if applicable.
fn run_complete(name: &str, force: bool) -> anyhow::Result<()> {
    use crate::registry::SessionStatus;

    // Pre-completion gate checks
    if !force {
        if let Err(e) = run_gate_checks(name) {
            eprintln!(
                "✗ cannot complete: gate checks failed.\n\
                 \n  → ccsm close {} to see what's needed\n\
                 → ccsm complete {} --force to bypass\n\
                 \n{e}",
                name, name,
            );
            anyhow::bail!("{} gate checks failed — fix issues or use --force", ErrorCode::Gate);
        }
        println!();
        println!(
            "\
🔍 Self-review:
  [ ] Tests pass?
  [ ] All changes committed and pushed?
  [ ] Scope fulfilled? Anything left undocumented?
  [ ] Dependencies resolved?
  [ ] Detail file tags and progress log are current?"
        );
    }

    let workspace = workspace_path();

    // Phase 1: Remove worktree if one exists (best-effort)
    let has_worktree = commands::worktree::worktree_path_for(&workspace, name).exists();

    if has_worktree {
        if let Err(e) = commands::worktree::remove_worktree(&workspace, name, force) {
            // Don't fail completion — warn and continue
            eprintln!("warning: worktree removal failed: {e}");
            eprintln!("  (the session will still be marked as completed)");
        }
    }

    // Phase 2: Status transition (locked)
    mutate_session(name, "complete", |entry| {
        entry.status = SessionStatus::Completed;
        entry.completed = crate::registry::now_iso();
    })?;

    crate::registry::sync_status_line(name);
    Ok(())
}

/// `ccsm start|complete|block|abandon <name>` — status transitions.
fn run_status(name: &str, action: &str, force: bool) -> anyhow::Result<()> {
    use crate::registry::SessionStatus;

    // Pre-completion gate: refuse to complete if detail file is hollow
    if action == "complete" && !force {
        if let Err(e) = run_gate_checks(name) {
            eprintln!(
                "✗ cannot complete: gate checks failed.\n\
                 \n  → ccsm close {} to see what's needed\n\
                 → ccsm complete {} --force to bypass\n\
                 \n{e}",
                name, name,
            );
            anyhow::bail!("{} gate checks failed — fix issues or use --force", ErrorCode::Gate);
        }
        // Gate passed — print the self-review checklist
        println!();
        println!(
            "\
🔍 Self-review:
  [ ] Tests pass?
  [ ] All changes committed and pushed?
  [ ] Scope fulfilled? Anything left undocumented?
  [ ] Dependencies resolved?
  [ ] Detail file tags and progress log are current?"
        );
    }

    let new_status = match action {
        "start" => SessionStatus::InProgress,
        "complete" => SessionStatus::Completed,
        "block" => SessionStatus::Blocked,
        "abandon" => SessionStatus::Abandoned,
        _ => anyhow::bail!("{} unknown status action: {}", ErrorCode::BadStatus, action),
    };
    mutate_session(name, action, |entry| {
        entry.status = new_status;
        if action == "complete" || action == "abandon" {
            entry.completed = crate::registry::now_iso();
        }
    })?;

    // Sync status line to detail file
    crate::registry::sync_status_line(name);

    // Nudge at session start: agent is about to fill scope — remind about checklist
    if action == "start" {
        eprintln!(
            "💡 multi-step? `ccsm checklist {} --init` to add sub-task tracking",
            name,
        );
    }

    Ok(())
}

/// Sync the `> **status** | started ... | completed ...` line in the detail file
/// to reflect the current registry state.
/// `ccsm refresh <name> [--reason]` — retire current session, spawn fresh.
///
/// Use when the context window is bloated (>40%) and the model gets biased.
/// Moves the current session_id to `retired_session_ids` with timestamp and reason,
/// then spawns a fresh agent (no --resume) with `CCSM_SESSION` injected so the
/// new agent knows which ccsm session it serves.
fn run_refresh(name: &str, reason: Option<&str>, workspace: &PathBuf, home: &PathBuf, consumer: Consumer) -> anyhow::Result<()> {
    let now = now_iso_ts();
    let reason_text = reason.unwrap_or("context refresh");

    // ── Phase 1: Retire current session_id, save, auto-note (locked) ──
    {
        let (mut reg, _lock) = crate::registry::WorkspaceRegistry::load_locked()?;
        let entry = reg
            .sessions
            .iter_mut()
            .rev()
            .find(|e| e.name == name)
            .ok_or_else(|| anyhow::anyhow!("{} no session named '{}'", ErrorCode::NoSession, name))?;

        if entry.status != crate::registry::SessionStatus::InProgress {
            anyhow::bail!(
                "session '{}' is {} — only in_progress sessions can be refreshed",
                name, entry.status,
            );
        }

        // Retire current session_id if one exists
        if !entry.session_id.is_empty() {
            entry.retired_session_ids.push(crate::registry::RetiredSession {
                id: entry.session_id.clone(),
                retired_at: now.clone(),
                reason: reason_text.to_string(),
            });
        }

        // Clear identity fields — fresh session repopulates them
        entry.session_id.clear();
        entry.pids.clear();
        entry.started.clear();

        reg.updated = now.clone();
        reg.save()?;
    } // lock released

    // ── Phase 2: Auto-note to progress log ──────────────────────────
    let retired_count = {
        let reg = crate::registry::WorkspaceRegistry::load()?;
        reg.sessions
            .iter()
            .find(|s| s.name == name)
            .map(|s| s.retired_session_ids.len())
            .unwrap_or(0)
    };

    let note_text = if retired_count <= 1 {
        format!("Refreshed session — fresh context (reason: {})", reason_text)
    } else {
        format!(
            "Refreshed session ({}th refresh) — fresh context (reason: {})",
            retired_count, reason_text,
        )
    };
    // Best-effort note — don't fail the whole operation if this errors
    let _ = run_note(name, &note_text, None);

    // ── Phase 3: Spawn fresh agent ──────────────────────────────────
    let mut cmd = std::process::Command::new(consumer.binary());
    cmd.current_dir(workspace);
    cmd.env("CCSM_SESSION", name);
    match consumer {
        Consumer::Claude => {
            cmd.arg("-n").arg(name);
        }
        Consumer::Pi => {
            cmd.arg("-n").arg(name);
        }
        Consumer::OpenCode => {
            // OpenCode TUI: no name/title flag at top level
        }
    }

    let bin = consumer.binary();
    let refresh_detail = if retired_count <= 1 {
        format!("{} (fresh, 1 refresh)", bin)
    } else {
        format!("{} (fresh, {} refreshes)", bin, retired_count)
    };
    action_msg("refreshing", name, &refresh_detail);

    let before_ts = std::time::SystemTime::now()
        .duration_since(std::time::UNIX_EPOCH)
        .unwrap()
        .as_millis() as i64;
    let mut child = cmd.spawn()?;
    let child_pid = child.id();

    // ── Phase 4: Write pid to registry (locked) ──────────────────────
    {
        let (mut reg, _lock) = crate::registry::WorkspaceRegistry::load_locked()?;
        match reg.sessions.iter_mut().rev().find(|e| e.name == name) {
            Some(entry) => entry.pids = vec![child_pid],
            None => anyhow::bail!(
                "internal error: session '{}' vanished from registry between Phase 1 and Phase 4",
                name
            ),
        }
        reg.updated = now_iso_ts();
        reg.save()?;
    }

    // ── Phase 5: Poll for session file, harvest session_id ───────────
    if consumer.is_claude() {
        // Claude: PID-based session file harvesting
        let session_file = consumer.live_session_file(home, child_pid).unwrap();
        let mut found = false;
        for _ in 0..50 {
            if session_file.exists() {
                found = true;
                break;
            }
            std::thread::sleep(std::time::Duration::from_millis(100));
        }
        if !found {
            anyhow::bail!(
                "{} did not write a session file at {} within 5s.\n\
                 {} may have failed to start. Check for errors above.",
                bin, session_file.display(), bin,
            );
        }

        // Harvest session_id + started (locked)
        {
            let (mut reg, _lock) = crate::registry::WorkspaceRegistry::load_locked()?;
            let entry = match reg.sessions.iter_mut().rev().find(|e| e.name == name) {
                Some(e) => e,
                None => anyhow::bail!(
                    "internal error: session '{}' vanished from registry between Phase 1 and Phase 6",
                    name
                ),
            };

            match std::fs::read_to_string(&session_file) {
                Ok(contents) => match serde_json::from_str::<crate::session::Session>(&contents) {
                    Ok(s) => {
                        if entry.session_id.is_empty() {
                            entry.session_id = s.session_id;
                        }
                        if entry.started.is_empty() {
                            entry.started = crate::registry::format_ts(s.started_at);
                        }
                        reg.updated = now_iso_ts();
                    }
                    Err(e) => {
                        eprintln!(
                            "warning: failed to parse session file {}: {}. \
                             Session tracking may be incomplete.",
                            session_file.display(), e
                        );
                    }
                },
                Err(e) => {
                    eprintln!(
                        "warning: failed to read session file {}: {}. \
                         Session tracking may be incomplete.",
                        session_file.display(), e
                    );
                }
            }
            reg.save()?;
        }
    } else if consumer.is_opencode() {
        // OpenCode: SQLite-based session polling
        let db_path = crate::consumer::opencode_db_path(home);
        let harvested_id = crate::consumer::opencode_harvest_session(
            &db_path,
            &workspace.to_string_lossy(),
            before_ts,
        );
        if let Some(ref sid) = harvested_id {
            {
                let (mut reg, _lock) =
                    crate::registry::WorkspaceRegistry::load_locked()?;
                let entry = match reg.sessions.iter_mut().rev().find(|e| e.name == name) {
                    Some(e) => e,
                    None => anyhow::bail!(
                        "internal error: session '{}' vanished from registry between Phase 1 and Phase 6",
                        name
                    ),
                };
                if entry.session_id.is_empty() {
                    entry.session_id.clone_from(sid);
                }
                if entry.started.is_empty() {
                    entry.started = crate::registry::now_iso();
                }
                reg.updated = crate::registry::now_iso();
                reg.save()?;
            }
            // Best-effort: update opencode session title
            if let Err(e) = crate::consumer::opencode_update_title(&db_path, sid, name) {
                eprintln!("warning: failed to update opencode session title: {e}");
            }
        } else {
            eprintln!("  warning: opencode did not create a session within 5s");
        }
    } else {
        // Pi: no PID-based session file harvesting
        eprintln!("  (session tracking will populate on next `ccsm attach` call)");
    }

    // ── Phase 6: Wait for child ──────────────────────────────────────
    let status = child.wait()?;

    // ── Phase 7: Clear stale pids (locked) ───────────────────────────
    {
        let (mut reg, _lock) = crate::registry::WorkspaceRegistry::load_locked()?;
        match reg.sessions.iter_mut().rev().find(|e| e.name == name) {
            Some(entry) => {
                entry.pids.clear();
                reg.updated = now_iso_ts();
            }
            None => {
                eprintln!(
                    "warning: session '{}' not found in registry at cleanup — \
                     may have been removed while {} was running",
                    name, bin,
                );
            }
        }
        reg.save()?;
    }

    if !status.success() {
        anyhow::bail!("{} exited with {status}", bin);
    }
    Ok(())
}

/// `ccsm pending <name>` — reset to pending, clear identity fields.
fn run_pending(name: &str) -> anyhow::Result<()> {
    let workspace = std::env::current_dir()?;

    // Best-effort worktree removal before resetting (no lock needed)
    if let Err(e) = commands::worktree::remove_worktree(&workspace, name, false) {
        // Only warn, don't fail — the session reset is more important
        eprintln!("  (worktree cleanup skipped: {e})");
    }

    let (mut reg, _lock) = crate::registry::WorkspaceRegistry::load_locked()?;
    let entry = reg
        .sessions
        .iter_mut()
        .find(|s| s.name == name)
        .ok_or_else(|| anyhow::anyhow!("{} no session named '{}'", ErrorCode::NoSession, name))?;
    entry.status = crate::registry::SessionStatus::Pending;
    entry.session_id.clear();
    entry.pids.clear();
    entry.started.clear();
    entry.completed.clear();
    entry.consumer.clear();
    entry.retired_session_ids.clear();
    entry.group = None;
    entry.tags.clear();
    entry.depends_on.clear();
    reg.updated = crate::registry::now_iso();
    reg.save()?;
    action_msg("pending", name, "reset (identity fields cleared)");
    Ok(())
}

/// `ccsm scope <name> <text>` — set the scope field.
fn run_set_field(name: &str, _field: &str, value: &str) -> anyhow::Result<()> {
    mutate_session(name, "scope updated", |entry| {
        entry.scope = value.to_string();
    })?;
    // Sync to detail file
    update_detail_section(name, "## Scope / Plan", value).ok();
    Ok(())
}

/// `ccsm tag <name> <tags...>` — replace tags.
fn run_set_tags(name: &str, tags: &[String]) -> anyhow::Result<()> {
    let tag_str = tags.join(", ");
    let _ = mutate_session(name, "tagged", |entry| {
        entry.tags = tags.to_vec();
    });
    if !output_format_json() {
        println!("  tags: {}", tag_str);
    }
    // Sync to detail file
    update_detail_section(name, "## Tags", &tag_str).ok();
    Ok(())
}

/// `ccsm branch <name> <branch>` or `ccsm branch <name> --clear`
fn run_branch(name: &str, clear: bool, branch: &[String]) -> anyhow::Result<()> {
    let value = if clear {
        String::new()
    } else {
        branch.join(" ")
    };
    let _ = mutate_session(name, "branch set", |entry| {
        entry.branch = value.clone();
    });
    if !output_format_json() {
        if value.is_empty() {
            println!("  branch: cleared");
        } else {
            println!("  branch: {}", value);
        }
    }
    // Sync to detail file
    update_detail_section(name, "## Branch", &value).ok();
    Ok(())
}

/// Update a section body in the session detail file. Silently skips if the
/// detail file doesn't exist (it might not for simple sessions).
fn update_detail_section(name: &str, header: &str, body: &str) -> anyhow::Result<()> {
    let Ok(ctx) = crate::registry::resolve_or_create_identity() else {
        return Ok(());
    };
    let detail_path = crate::registry::global_detail_path(&ctx.id, name);

    if !detail_path.exists() {
        return Ok(());
    }

    let contents = std::fs::read_to_string(&detail_path)?;
    let updated = crate::registry::replace_detail_section(&contents, header, body);
    std::fs::write(&detail_path, updated)?;
    Ok(())
}

/// `ccsm group <name>` — overview of all sessions in a group.
/// `ccsm group <name> --roadmap` — render a markdown roadmap for the group.
/// `ccsm group <session> --group <g> [--rank free|<n>]` — assign to group.
/// `ccsm group <session> --clear` — remove from group.
fn run_group(name: Option<&str>, list: bool, group: Option<&str>, rank: Option<&str>, clear: bool, goal: Option<&str>, roadmap: bool) -> anyhow::Result<()> {
    use crate::registry::{Group, GroupRank};

    let ctx = crate::registry::resolve_or_create_identity()?;

    // --list: list all groups in the workspace
    if list {
        return run_groups_list();
    }

    // --roadmap: render a markdown roadmap for the group
    if roadmap {
        if group.is_some() || clear || goal.is_some() {
            anyhow::bail!("--roadmap can't be combined with --group, --clear, or --goal. Usage: ccsm group <group-name> --roadmap");
        }
        let name = name.ok_or_else(|| anyhow::anyhow!("group NAME is required with --roadmap"))?;
        return run_group_roadmap(name);
    }

    // All other modes require a name
    let name = name.ok_or_else(|| anyhow::anyhow!("NAME is required (or use --list to list all groups)"))?;

    // --goal: set group goal (name = group name, not session name)
    if let Some(goal_text) = goal {
        if group.is_some() || clear {
            anyhow::bail!("--goal can't be combined with --group or --clear. Use: ccsm group <group-name> --goal <text>");
        }
        set_group_goal(name, goal_text)?;
        action_msg("group-goal", name, goal_text);
        return Ok(());
    }

    if clear {
        // Remove session from its group
        let (mut reg, _lock) = crate::registry::WorkspaceRegistry::load_locked()?;
        let entry = reg
            .sessions
            .iter_mut()
            .find(|s| s.name == name)
            .ok_or_else(|| anyhow::anyhow!("{} no session named '{}'", ErrorCode::NoSession, name))?;
        if entry.group.is_none() {
            action_msg("ungrouped", name, "not in a group");
            return Ok(());
        }
        let old_group = entry.group.take().unwrap();
        reg.updated = crate::registry::now_iso();
        reg.save()?;
        let deleted = update_group_members(&old_group.name, &reg)?;
        if deleted {
            action_msg("ungrouped", name, &format!("removed from '{}' (group file deleted)", old_group.name));
        } else {
            action_msg("ungrouped", name, &format!("removed from '{}'", old_group.name));
        }
        return Ok(());
    }

    if let Some(group_name) = group {
        // Assign session to a group
        if !crate::registry::is_kebab_case(group_name) {
            anyhow::bail!("{} group name '{}' must be kebab-case", ErrorCode::Invalid, group_name);
        }
        let rank = match rank {
            None => GroupRank::Free,
            Some("free") => GroupRank::Free,
            Some(n) => {
                let num: u32 = n.parse()
                    .map_err(|_| anyhow::anyhow!("rank must be 'free' or a number, got '{}'", n))?;
                GroupRank::Number(num)
            }
        };
        let (mut reg, _lock) = crate::registry::WorkspaceRegistry::load_locked()?;
        let entry = reg
            .sessions
            .iter_mut()
            .find(|s| s.name == name)
            .ok_or_else(|| anyhow::anyhow!("{} no session named '{}'", ErrorCode::NoSession, name))?;
        entry.group = Some(Group {
            name: group_name.to_string(),
            rank,
        });
        reg.updated = crate::registry::now_iso();
        reg.save()?;

        // Update detail file — add/update ## Group section
        let detail_path = crate::registry::global_detail_path(&ctx.id, name);
        if detail_path.exists() {
            if let Ok(contents) = std::fs::read_to_string(&detail_path) {
                let body = format!("- **Group:** {}\n- **Rank:** {}", group_name, rank);
                let updated = crate::registry::replace_detail_section(&contents, "## Group", &body);
                let _ = std::fs::write(&detail_path, updated);
            }
        }

        // Create or update the group detail file
        ensure_group_file(group_name, &reg)?;

        action_msg("grouped", name, &format!("{} rank {}", group_name, rank));
        return Ok(());
    }

    // Neither --clear nor --group: treat `name` as a group name, show overview
    let reg = crate::registry::WorkspaceRegistry::load()?;
    let mut members: Vec<_> = reg
        .sessions
        .iter()
        .filter(|s| s.group.as_ref().is_some_and(|g| g.name == name))
        .collect();

    if members.is_empty() {
        if output_format_json() {
            println!("{}", serde_json::json!({"ok": true, "group": name, "members": []}));
        } else {
            println!("(no sessions in group '{}')", name);
        }
        return Ok(());
    }

    // Sort: by rank (numeric first, then free alphabetical)
    members.sort_by(|a, b| {
        let ra = a.group.as_ref().map(|g| &g.rank);
        let rb = b.group.as_ref().map(|g| &g.rank);
        match (ra, rb) {
            (Some(GroupRank::Number(na)), Some(GroupRank::Number(nb))) => na.cmp(nb),
            (Some(GroupRank::Number(_)), Some(GroupRank::Free)) => std::cmp::Ordering::Greater,
            (Some(GroupRank::Free), Some(GroupRank::Number(_))) => std::cmp::Ordering::Less,
            _ => a.name.cmp(&b.name),
        }
    });

    if output_format_json() {
        let members_json: Vec<_> = members.iter().map(|m| {
            let rank_str = m.group.as_ref().map(|g| g.rank.to_string()).unwrap_or_default();
            serde_json::json!({
                "name": m.name,
                "status": m.status.to_string(),
                "rank": rank_str,
                "goal": m.goal,
            })
        }).collect();
        let out = serde_json::json!({"ok": true, "group": name, "members": members_json});
        println!("{}", out);
        return Ok(());
    }

    println!("group '{}':", name);
    for m in &members {
        let rank_str = m.group.as_ref().map(|g| g.rank.to_string()).unwrap_or_default();
        println!("  {:12}  {:30}  rank: {}", m.status.to_string(), m.name, rank_str);
    }
    println!("{} member{}", members.len(), if members.len() == 1 { "" } else { "s" });

    // Display group detail file if it exists
    let gpath = group_file_path(name);
    if gpath.exists() {
        if let Ok(contents) = std::fs::read_to_string(&gpath) {
            let sections = crate::registry::parse_sections(&contents);
            if let Some((_, goal_body)) = sections.iter().find(|(h, _)| h == "Goal") {
                let goal = goal_body.trim();
                if !goal.is_empty() && !goal.starts_with('_') {
                    println!("  Goal: {}", goal);
                }
            }
        }
    }

    Ok(())
}

/// `ccsm group --list` — list all groups in the workspace.
fn run_groups_list() -> anyhow::Result<()> {
    use std::collections::BTreeMap;

    let reg = crate::registry::WorkspaceRegistry::load()?;

    // Collect sessions by group name
    let mut groups: BTreeMap<&str, Vec<&crate::registry::WorkspaceSession>> = BTreeMap::new();
    for s in &reg.sessions {
        if let Some(ref g) = s.group {
            groups.entry(g.name.as_str()).or_default().push(s);
        }
    }

    if groups.is_empty() {
        if output_format_json() {
            println!("{}", serde_json::json!({"ok": true, "groups": []}));
        } else {
            println!("(no groups in workspace)");
        }
        return Ok(());
    }

    if output_format_json() {
        let groups_json: Vec<_> = groups.iter().map(|(name, members)| {
            let count = members.len();
            let in_progress = members.iter().filter(|m| m.status == crate::registry::SessionStatus::InProgress).count();
            let pending = members.iter().filter(|m| m.status == crate::registry::SessionStatus::Pending).count();
            let goal_snippet = {
                let path = group_file_path(name);
                if path.exists() {
                    if let Ok(contents) = std::fs::read_to_string(&path) {
                        let sections = crate::registry::parse_sections(&contents);
                        sections.iter()
                            .find(|(h, _)| h == "Goal")
                            .map(|(_, b)| b.trim().to_string())
                            .filter(|g| !g.is_empty() && !g.starts_with('_'))
                            .unwrap_or_default()
                    } else { String::new() }
                } else { String::new() }
            };
            serde_json::json!({
                "name": name,
                "session_count": count,
                "in_progress": in_progress,
                "pending": pending,
                "goal": goal_snippet,
            })
        }).collect();
        println!("{}", serde_json::json!({"ok": true, "groups": groups_json}));
        return Ok(());
    }

    println!("{} group{}:", groups.len(), if groups.len() == 1 { "" } else { "s" });
    for (name, members) in &groups {
        // Read goal snippet from group detail file
        let goal_snippet = {
            let path = group_file_path(name);
            if path.exists() {
                if let Ok(contents) = std::fs::read_to_string(&path) {
                    let sections = crate::registry::parse_sections(&contents);
                    sections
                        .iter()
                        .find(|(h, _)| h == "Goal")
                        .map(|(_, b)| b.trim().to_string())
                        .filter(|g| !g.is_empty() && !g.starts_with('_'))
                        .unwrap_or_default()
                } else {
                    String::new()
                }
            } else {
                String::new()
            }
        };

        let count = members.len();
        let statuses: Vec<_> = members.iter().map(|m| m.status.to_string()).collect();
        let in_progress = statuses.iter().filter(|s| *s == "in_progress").count();
        let pending = statuses.iter().filter(|s| *s == "pending").count();

        print!("  {:30}  {} session{}", name, count, if count == 1 { "" } else { "s" });
        if in_progress > 0 {
            print!(" ({} in_progress)", in_progress);
        }
        if pending > 0 {
            print!(" ({} pending)", pending);
        }
        if !goal_snippet.is_empty() {
            print!(" — {}", goal_snippet);
        }
        println!();
    }
    Ok(())
}

/// `ccsm group-deps <name>` — render the dependency tree for all sessions in a group.
fn run_group_deps(group_name: &str) -> anyhow::Result<()> {
    use crate::registry::SessionStatus;

    let reg = crate::registry::WorkspaceRegistry::load()?;

    let members: Vec<_> = reg
        .sessions
        .iter()
        .filter(|s| s.group.as_ref().is_some_and(|g| g.name == group_name))
        .collect();

    if members.is_empty() {
        anyhow::bail!("{} no sessions in group '{}'", ErrorCode::NoSession, group_name);
    }

    if output_format_json() {
        let tree: Vec<_> = members.iter().map(|m| {
            let deps: Vec<_> = m.depends_on.iter().map(|dep| {
                let dep_status = reg.sessions.iter()
                    .find(|s| &s.name == dep)
                    .map(|s| s.status.to_string())
                    .unwrap_or_else(|| "unknown".to_string());
                serde_json::json!({"name": dep, "status": dep_status})
            }).collect();
            serde_json::json!({
                "name": m.name,
                "status": m.status.to_string(),
                "goal": m.goal,
                "depends_on": deps,
            })
        }).collect();
        let out = serde_json::json!({"ok": true, "group": group_name, "tree": tree});
        println!("{}", out);
        return Ok(());
    }

    println!("dependency tree for group '{}':\n", group_name);

    for m in &members {
        let status_marker = match m.status {
            SessionStatus::Completed => "✓",
            SessionStatus::InProgress => "→",
            SessionStatus::Pending => "○",
            SessionStatus::Blocked => "!",
            _ => "·",
        };
        println!("  {} {}  {}", status_marker, m.name, m.goal);

        if m.depends_on.is_empty() {
            println!("    (no dependencies)");
        } else {
            for dep in &m.depends_on {
                let dep_status = reg
                    .sessions
                    .iter()
                    .find(|s| &s.name == dep)
                    .map(|s| s.status.to_string())
                    .unwrap_or_else(|| "unknown".to_string());
                let dep_marker = if dep_status == "completed" {
                    "✓"
                } else if dep_status == "in_progress" {
                    "→"
                } else {
                    "○"
                };
                println!("    {} depends on {} {} ({})", "├─", dep_marker, dep, dep_status);
            }
        }
        println!();
    }

    Ok(())
}

/// `ccsm group <name> --roadmap` — render a markdown roadmap for the group.
///
/// Output: group goal header, markdown table (Rank | Session | Status | Goal | Scope),
/// then a Mermaid dependency graph if any sessions have depends_on.
fn run_group_roadmap(group_name: &str) -> anyhow::Result<()> {
    use crate::registry::{GroupRank, SessionStatus};

    let reg = crate::registry::WorkspaceRegistry::load()?;

    let mut members: Vec<&crate::registry::WorkspaceSession> = reg
        .sessions
        .iter()
        .filter(|s| s.group.as_ref().is_some_and(|g| g.name == group_name))
        .collect();

    if members.is_empty() {
        anyhow::bail!("{} no sessions in group '{}'", ErrorCode::NoSession, group_name);
    }

    // Sort by rank (same as everywhere)
    members.sort_by(|a, b| {
        let ra = a.group.as_ref().map(|g| &g.rank);
        let rb = b.group.as_ref().map(|g| &g.rank);
        match (ra, rb) {
            (Some(GroupRank::Number(na)), Some(GroupRank::Number(nb))) => na.cmp(nb),
            (Some(GroupRank::Number(_)), Some(GroupRank::Free)) => std::cmp::Ordering::Greater,
            (Some(GroupRank::Free), Some(GroupRank::Number(_))) => std::cmp::Ordering::Less,
            _ => a.name.cmp(&b.name),
        }
    });

    // Read group goal from group detail file
    let group_goal = {
        let gpath = group_file_path(group_name);
        if gpath.exists() {
            if let Ok(contents) = std::fs::read_to_string(&gpath) {
                let sections = crate::registry::parse_sections(&contents);
                sections
                    .iter()
                    .find(|(h, _)| h == "Goal")
                    .map(|(_, b)| b.trim().to_string())
                    .filter(|g| !g.is_empty() && !g.starts_with('_'))
                    .unwrap_or_default()
            } else {
                String::new()
            }
        } else {
            String::new()
        }
    };

    // Header
    println!("# Group Roadmap: {}", group_name);
    if !group_goal.is_empty() {
        println!();
        println!("**Goal:** {}", group_goal);
    }

    // Markdown table
    println!();
    println!("| Rank | Session | Status | Goal | Scope |");
    println!("|------|---------|--------|------|-------|");

    for m in &members {
        let rank_str = m.group.as_ref().map(|g| g.rank.to_string()).unwrap_or_default();
        let icon = status_icon(&m.status);

        let goal_owned = read_session_section(&m.name, "Goal");
        let goal: &str = if goal_owned.is_empty() { &m.goal } else { &goal_owned };
        let scope_owned = read_session_section(&m.name, "Scope / Plan");
        let scope: &str = if scope_owned.is_empty() { &m.scope } else { &scope_owned };

        println!(
            "| {} | {} | {} {} | {} | {} |",
            rank_str,
            m.name,
            icon,
            m.status,
            truncate_md(goal, 60),
            truncate_md(scope, 60),
        );
    }

    // Dependency graph (Mermaid) if any
    let has_deps = members.iter().any(|m| !m.depends_on.is_empty());
    if has_deps {
        println!();
        println!("## Dependencies");
        println!();
        println!("```mermaid");
        println!("graph TD");

        // Collect all nodes (members + deps that might be in other groups)
        let mut seen: std::collections::BTreeSet<String> = std::collections::BTreeSet::new();

        for m in &members {
            let node_id = m.name.replace(['-', '.'], "_");
            if seen.insert(node_id.clone()) {
                let icon = status_icon(&m.status);
                println!("    {}[\"{} {}\"]", node_id, icon, m.name);
            }
            for dep in &m.depends_on {
                let dep_id = dep.replace(['-', '.'], "_");
                let dep_status = reg
                    .sessions
                    .iter()
                    .find(|s| &s.name == dep)
                    .map(|s| s.status)
                    .unwrap_or(SessionStatus::Pending);
                let dep_icon = status_icon(&dep_status);
                if seen.insert(dep_id.clone()) {
                    println!("    {}[\"{} {}\"]", dep_id, dep_icon, dep);
                }
                // Edge: dep → member (member depends on dep)
                println!("    {} --> {}", dep_id, node_id);
            }
        }

        println!("```");
    }

    println!();
    let s = if members.len() == 1 { "" } else { "s" };
    println!("--- {} session{} ---", members.len(), s);

    Ok(())
}

/// Status icon for roadmap table + mermaid labels.
fn status_icon(status: &crate::registry::SessionStatus) -> &'static str {
    match status {
        crate::registry::SessionStatus::Completed => "✓",
        crate::registry::SessionStatus::InProgress => "→",
        crate::registry::SessionStatus::Pending => "○",
        crate::registry::SessionStatus::Blocked => "!",
        _ => "·",
    }
}

/// Read a section from a session detail file.
fn read_session_section(name: &str, header: &str) -> String {
    let Ok(ctx) = crate::registry::resolve_or_create_identity() else {
        return String::new();
    };
    let detail_path = crate::registry::global_detail_path(&ctx.id, name);
    if detail_path.exists() {
        if let Ok(contents) = std::fs::read_to_string(&detail_path) {
            let sections = crate::registry::parse_sections(&contents);
            if let Some((_, body)) = sections.iter().find(|(h, _)| h == header) {
                let trimmed = body.trim();
                if !trimmed.is_empty()
                    && !trimmed.starts_with('_')
                    && !trimmed.starts_with("(fill in")
                {
                    return trimmed.to_string();
                }
            }
        }
    }
    String::new()
}

/// Escape pipes in markdown table cells.
fn md_escape_pipe(s: &str) -> String {
    s.replace('|', "\\|")
}

/// Truncate for markdown table readability.
fn truncate_md(s: &str, max_len: usize) -> String {
    let escaped = md_escape_pipe(s);
    if escaped.len() > max_len {
        format!("{}...", &escaped[..max_len.saturating_sub(3)])
    } else {
        escaped
    }
}

/// `ccsm depend <name>` — list dependencies.
/// `ccsm depend <name> --on <dep>` — add a dependency.
/// `ccsm depend <name> --clear` — remove all dependencies.
fn run_depend(name: &str, on: Option<&str>, clear: bool) -> anyhow::Result<()> {
    let (mut reg, _lock) = crate::registry::WorkspaceRegistry::load_locked()?;

    // Check session exists first (immutable borrow)
    if !reg.sessions.iter().any(|s| s.name == name) {
        anyhow::bail!("{} no session named '{}'", ErrorCode::NoSession, name);
    }

    if clear {
        // Mutate, extract deps, save
        let deps = {
            let entry = reg.sessions.iter_mut().find(|s| s.name == name).unwrap();
            if entry.depends_on.is_empty() {
                action_msg("depend-clear", name, "no dependencies to clear");
                return Ok(());
            }
            entry.depends_on.clear();
            entry.depends_on.clone()
        };
        reg.updated = crate::registry::now_iso();
        reg.save()?;
        update_deps_in_detail(name, &deps)?;
        action_msg("depend-clear", name, "cleared");
        return Ok(());
    }

    if let Some(dep) = on {
        if dep == name {
            anyhow::bail!("{} a session cannot depend on itself", ErrorCode::Dep);
        }
        // Validate: dep session must exist
        let dep_session = reg
            .sessions
            .iter()
            .find(|s| s.name == dep)
            .ok_or_else(|| anyhow::anyhow!("{} no session named '{}' — dependencies must be between existing sessions", ErrorCode::NoSession, dep))?;
        // Validate: both sessions must be in the same group
        let session_group = reg
            .sessions
            .iter()
            .find(|s| s.name == name)
            .and_then(|s| s.group.as_ref().map(|g| g.name.clone()));
        let dep_group = dep_session.group.as_ref().map(|g| g.name.clone());
        if session_group != dep_group {
            anyhow::bail!(
                "{} dependencies must be within the same group — '{}' is in group {:?}, '{}' is in group {:?}",
                ErrorCode::Dep, name, session_group, dep, dep_group
            );
        }
        let deps = {
            let entry = reg.sessions.iter_mut().find(|s| s.name == name).unwrap();
            if entry.depends_on.iter().any(|d| d == dep) {
                action_msg("depend", name, &format!("already on '{}'", dep));
                return Ok(());
            }
            entry.depends_on.push(dep.to_string());
            entry.depends_on.clone()
        };
        reg.updated = crate::registry::now_iso();
        reg.save()?;
        update_deps_in_detail(name, &deps)?;
        action_msg("depend", name, &format!("on '{}'", dep));
        return Ok(());
    }

    // List deps (immutable read)
    let entry = reg.sessions.iter().find(|s| s.name == name).unwrap();
    if entry.depends_on.is_empty() {
        action_msg("depend", name, "none");
        return Ok(());
    }

    // JSON dep listing
    if output_format_json() {
        let deps: Vec<_> = entry.depends_on.iter().map(|dep| {
            let status = reg.sessions.iter()
                .find(|s| &s.name == dep)
                .map(|s| s.status.to_string())
                .unwrap_or_else(|| "unknown".to_string());
            serde_json::json!({"name": dep, "status": status})
        }).collect();
        let out = serde_json::json!({"ok": true, "name": name, "depends_on": deps});
        println!("{}", out);
    } else {
        println!("{} depends on:", name);
        for dep in &entry.depends_on {
            let status = reg
                .sessions
                .iter()
                .find(|s| &s.name == dep)
                .map(|s| s.status.to_string())
                .unwrap_or_else(|| "unknown".to_string());
            let marker = if status == "completed" { "✓" } else { "○" };
            println!("  {} {} ({})", marker, dep, status);
        }
    }
    Ok(())
}

/// Sync the `depends_on` list to the session detail file `## Dependencies` section.
fn update_deps_in_detail(
    name: &str,
    deps: &[String],
) -> anyhow::Result<()> {
    let Ok(ctx) = crate::registry::resolve_or_create_identity() else {
        return Ok(());
    };
    let detail_path = crate::registry::global_detail_path(&ctx.id, name);
    if !detail_path.exists() {
        return Ok(());
    }
    let contents = std::fs::read_to_string(&detail_path)?;
    let body = if deps.is_empty() {
        "(none)".to_string()
    } else {
        deps.iter()
            .map(|d| format!("- {}", d))
            .collect::<Vec<_>>()
            .join("\n")
    };
    let updated = crate::registry::replace_detail_section(&contents, "## Dependencies", &body);
    std::fs::write(&detail_path, updated)?;
    Ok(())
}

// ── Group Detail File Helpers ───────────────────────────────────────

fn group_dir() -> std::path::PathBuf {
    let ctx = crate::registry::resolve_or_create_identity()
        .unwrap_or_else(|_| std::process::exit(1));
    crate::registry::global_data_dir(&ctx.id).join("session-group")
}

fn group_file_path(group_name: &str) -> std::path::PathBuf {
    let ctx = crate::registry::resolve_or_create_identity()
        .unwrap_or_else(|_| std::process::exit(1));
    crate::registry::global_group_path(&ctx.id, group_name)
}

/// Create or update the group detail file. Called when a session joins a group.
fn ensure_group_file(
    group_name: &str,
    reg: &crate::registry::WorkspaceRegistry,
) -> anyhow::Result<()> {
    let members: Vec<_> = reg
        .sessions
        .iter()
        .filter(|s| s.group.as_ref().is_some_and(|g| g.name == group_name))
        .collect();

    let members_body = if members.is_empty() {
        "_No members yet._".to_string()
    } else {
        members
            .iter()
            .map(|m| {
                let rank_str = m
                    .group
                    .as_ref()
                    .map(|g| g.rank.to_string())
                    .unwrap_or_default();
                format!("- {} ({}) [rank: {}]", m.name, m.status, rank_str)
            })
            .collect::<Vec<_>>()
            .join("\n")
    };

    let dir = group_dir();
    std::fs::create_dir_all(&dir)?;

    let path = group_file_path(group_name);
    if path.exists() {
        let contents = std::fs::read_to_string(&path)?;
        let updated =
            crate::registry::replace_detail_section(&contents, "## Members", &members_body);
        std::fs::write(&path, updated)?;
    } else {
        let template = format!(
            "<!--\n  Group: {name}\n  Sessions: {count}\n-->\n\n## Goal\n\n\
             _No goal set. Use `ccsm group {name} --goal <text>` to set one._\n\n\
             ## Scope\n\n\n\n## Members\n\n\
             <!-- Auto-generated — do not edit -->\n\n{members_body}\n\n## Notes\n\n\n",
            name = group_name,
            count = members.len(),
            members_body = members_body
        );
        std::fs::write(&path, template)?;
    }
    Ok(())
}

/// Refresh the Members section of a group detail file. Called when a session leaves a group.
/// Returns true if the file was deleted (no members left).
fn update_group_members(
    group_name: &str,
    reg: &crate::registry::WorkspaceRegistry,
) -> anyhow::Result<bool> {
    let path = group_file_path(group_name);
    if !path.exists() {
        return Ok(false);
    }

    let members: Vec<_> = reg
        .sessions
        .iter()
        .filter(|s| s.group.as_ref().is_some_and(|g| g.name == group_name))
        .collect();

    if members.is_empty() {
        // Auto-clean: delete the group detail file
        std::fs::remove_file(&path)?;
        // Try to remove the directory if empty (ignore errors)
        let _ = std::fs::remove_dir(path.parent().unwrap());
        return Ok(true);
    }

    let members_body = members
        .iter()
        .map(|m| {
            let rank_str = m
                .group
                .as_ref()
                .map(|g| g.rank.to_string())
                .unwrap_or_default();
            format!("- {} ({}) [rank: {}]", m.name, m.status, rank_str)
        })
        .collect::<Vec<_>>()
        .join("\n");

    let contents = std::fs::read_to_string(&path)?;
    let updated =
        crate::registry::replace_detail_section(&contents, "## Members", &members_body);
    std::fs::write(&path, updated)?;
    Ok(false)
}

/// Set the ## Goal section of a group detail file.
fn set_group_goal(
    group_name: &str,
    goal: &str,
) -> anyhow::Result<()> {
    let path = group_file_path(group_name);
    if path.exists() {
        let contents = std::fs::read_to_string(&path)?;
        let updated = crate::registry::replace_detail_section(&contents, "## Goal", goal);
        std::fs::write(&path, updated)?;
    } else {
        // Create a minimal file with just the goal set
        let dir = group_dir();
        std::fs::create_dir_all(&dir)?;
        let template = format!(
            "<!--\n  Group: {name}\n  Sessions: 0\n-->\n\n## Goal\n\n{goal}\n\n\
             ## Scope\n\n\n\n## Members\n\n\
             <!-- Auto-generated — do not edit -->\n\n_No members yet._\n\n## Notes\n\n\n",
            name = group_name,
            goal = goal
        );
        std::fs::write(&path, template)?;
    }
    Ok(())
}

/// `ccsm next <group>` — print the next session to work on in a group.
///
/// Priority: in_progress > pending by rank (numeric: lowest first, free: alphabetical).
/// Tie-break: alphabetical by name within same rank.
/// Skips sessions whose dependencies are not all completed.
/// Exits 0 with no output if all sessions in the group are done or blocked.
fn run_next(group_name: &str) -> anyhow::Result<()> {
    use crate::registry::{GroupRank, SessionStatus};

    let reg = crate::registry::WorkspaceRegistry::load()?;

    // Helper: true if all deps of this session are completed
    let is_unblocked = |s: &&crate::registry::WorkspaceSession| -> bool {
        s.depends_on.is_empty()
            || s.depends_on.iter().all(|dep| {
                reg.sessions
                    .iter()
                    .any(|r| &r.name == dep && r.status == SessionStatus::Completed)
            })
    };

    let mut members: Vec<_> = reg
        .sessions
        .iter()
        .filter(|s| s.group.as_ref().is_some_and(|g| g.name == group_name))
        .collect();

    if members.is_empty() {
        anyhow::bail!("{} no sessions in group '{}'", ErrorCode::NoSession, group_name);
    }

    // Sort for deterministic selection
    members.sort_by(|a, b| {
        let ra = a.group.as_ref().map(|g| &g.rank);
        let rb = b.group.as_ref().map(|g| &g.rank);
        match (ra, rb) {
            (Some(GroupRank::Number(na)), Some(GroupRank::Number(nb))) => na.cmp(nb),
            (Some(GroupRank::Number(_)), Some(GroupRank::Free)) => std::cmp::Ordering::Greater,
            (Some(GroupRank::Free), Some(GroupRank::Number(_))) => std::cmp::Ordering::Less,
            _ => a.name.cmp(&b.name),
        }
    });

    // 1. Prefer in_progress (unblocked only)
    let in_progress: Vec<_> = members
        .iter()
        .filter(|m| m.status == SessionStatus::InProgress && is_unblocked(m))
        .collect();
    if in_progress.len() == 1 {
        println!("{}", in_progress[0].name);
        return Ok(());
    }
    if in_progress.len() > 1 {
        eprintln!("warning: {} in_progress sessions in group '{}'", in_progress.len(), group_name);
        let pick = in_progress
            .iter()
            .max_by_key(|m| &m.started)
            .unwrap_or(&in_progress[0]);
        println!("{}", pick.name);
        return Ok(());
    }

    // 2. First pending by rank (unblocked only)
    let pending: Vec<_> = members
        .iter()
        .filter(|m| m.status == SessionStatus::Pending && is_unblocked(m))
        .collect();
    if let Some(pick) = pending.first() {
        println!("{}", pick.name);
        return Ok(());
    }

    // 3. All done or all blocked — nothing to do
    Ok(()) // exit 0, no output
}

/// `ccsm show <name>` — registry fields + detail file section list.
/// `ccsm show <name> --section <s>` — extract one section from detail file.
/// `ccsm show <name> --json` — output all fields as JSON.
fn run_show(name: &str, section: Option<&str>, json: bool, consumer: Consumer) -> anyhow::Result<()> {
    let ctx = crate::registry::resolve_or_create_identity()?;
    let reg = crate::registry::WorkspaceRegistry::load()?;
    let session = reg
        .sessions
        .iter()
        .find(|s| s.name == name)
        .ok_or_else(|| anyhow::anyhow!("{} no session named '{}'", ErrorCode::NoSession, name))?;

    let detail_path = crate::registry::global_detail_path(&ctx.id, name);

    // If --section is given, extract and print just that section.
    if let Some(sec) = section {
        if !detail_path.exists() {
            anyhow::bail!("{} no detail file for '{}' (expected {})", ErrorCode::Section, name, detail_path.display());
        }
        let contents = std::fs::read_to_string(&detail_path)?;
        let sections = crate::registry::parse_sections(&contents);
        let key = sec.to_lowercase().replace('-', " ");
        match sections.iter().find(|(h, _)| h.to_lowercase() == key) {
            Some((header, body)) => {
                if json || output_format_json() {
                    let out = serde_json::json!({
                        "ok": true,
                        "session": name,
                        "section": header,
                        "content": body.trim(),
                    });
                    println!("{}", out);
                } else {
                    println!("## {}\n{}", header, body.trim());
                }
            }
            None => {
                eprintln!("section '{}' not found. Available:", sec);
                for (h, _) in &sections {
                    eprintln!("  --section {}", h.to_lowercase().replace(' ', "-"));
                }
                anyhow::bail!("{} no such section", ErrorCode::Section);
            }
        }
        return Ok(());
    }

    // ── Read detail file for canonical goal/scope ─────────────────
    let detail_goal;
    let detail_scope;
    let detail_contents;
    let detail_path_exists = detail_path.exists();
    if detail_path.exists() {
        if let Ok(contents) = std::fs::read_to_string(&detail_path) {
            detail_contents = Some(contents);
            let sections = crate::registry::parse_sections(detail_contents.as_ref().unwrap());
            detail_goal = sections.iter().find(|(h, _)| h == "Goal")
                .map(|(_, b)| b.trim().to_string())
                .filter(|g| !g.is_empty() && !g.starts_with('_') && !g.starts_with("(fill in"));
            detail_scope = sections.iter().find(|(h, _)| h == "Scope / Plan")
                .map(|(_, b)| b.trim().to_string())
                .filter(|s| !s.is_empty() && !s.starts_with('_') && !s.starts_with("(fill in"));
        } else {
            detail_contents = None;
            detail_goal = None;
            detail_scope = None;
        }
    } else {
        detail_contents = None;
        detail_goal = None;
        detail_scope = None;
    }

    // ── JSON output ────────────────────────────────────────────────
    if json || output_format_json() {
        #[derive(serde::Serialize)]
        #[serde(rename_all = "snake_case")]
        struct ShowEntry {
            name: String,
            status: String,
            agent: String,
            goal: String,
            scope: String,
            tags: Vec<String>,
            group: Option<GroupJson>,
            session_id: String,
            pids: Vec<u32>,
            started: String,
            completed: String,
            consumer: String,
            depends_on: Vec<String>,
            branch: String,
            worktree: String,
            detail_file: Option<String>,
            has_detail_file: bool,
            sections: Vec<SectionJson>,
            retired: Vec<RetiredJson>,
        }
        #[derive(serde::Serialize)]
        struct GroupJson {
            name: String,
            rank: String,
        }
        #[derive(serde::Serialize)]
        struct SectionJson {
            header: String,
            lines: usize,
        }
        #[derive(serde::Serialize)]
        struct RetiredJson {
            id: String,
            retired_at: String,
            reason: String,
        }

        let goal = detail_goal.as_deref().unwrap_or(&session.goal);
        let scope = detail_scope.as_deref().unwrap_or(&session.scope);
        let agent_label = if session.consumer.is_empty() {
            consumer.to_string()
        } else {
            format!("{} (current)", session.consumer)
        };

        let sections: Vec<SectionJson> = if let Some(ref contents) = detail_contents {
            let secs = crate::registry::parse_sections(contents);
            secs.iter().map(|(h, b)| SectionJson {
                header: h.clone(),
                lines: b.lines().filter(|l| !l.trim().is_empty()).count(),
            }).collect()
        } else {
            Vec::new()
        };

        let entry = ShowEntry {
            name: session.name.clone(),
            status: session.status.to_string(),
            agent: agent_label,
            goal: goal.to_string(),
            scope: scope.to_string(),
            tags: session.tags.clone(),
            group: session.group.as_ref().map(|g| GroupJson {
                name: g.name.clone(),
                rank: g.rank.to_string(),
            }),
            session_id: session.session_id.clone(),
            pids: session.pids.clone(),
            started: session.started.clone(),
            completed: session.completed.clone(),
            consumer: session.consumer.clone(),
            depends_on: session.depends_on.clone(),
            branch: session.branch.clone(),
            worktree: if session.use_worktree {
                crate::commands::worktree::worktree_path_for(&ctx.root, &session.name).to_string_lossy().to_string()
            } else {
                String::new()
            },
            detail_file: detail_path_exists.then(|| detail_path.display().to_string()),
            has_detail_file: detail_path_exists,
            sections,
            retired: session.retired_session_ids.iter().map(|r| RetiredJson {
                id: r.id.clone(),
                retired_at: r.retired_at.clone(),
                reason: r.reason.clone(),
            }).collect(),
        };
        println!("{}", serde_json::to_string_pretty(&entry)?);
        return Ok(());
    }

    // ── Registry fields ──────────────────────────────────────────
    println!("name:       {}", session.name);
    println!("status:     {}", session.status);
    if !session.consumer.is_empty() {
        let current = consumer.to_string();
        let label = if session.consumer == current {
            format!("{} (current)", session.consumer)
        } else {
            format!("{} ⚠ running as {}", session.consumer, current)
        };
        println!("agent:      {}", label);
    }
    let goal = detail_goal.as_deref().unwrap_or(&session.goal);
    if !goal.is_empty() {
        println!("goal:       {}", goal);
    }
    let scope = detail_scope.as_deref().unwrap_or(&session.scope);
    if !scope.is_empty() {
        println!("scope:      {}", scope);
    }
    if !session.tags.is_empty() {
        println!("tags:       {}", session.tags.join(", "));
    }
    if !session.branch.is_empty() {
        println!("branch:     {}", session.branch);
    }
    if session.use_worktree {
        let wt = crate::commands::worktree::worktree_path_for(&ctx.root, &session.name);
        println!("worktree:   {}", wt.display());
    }
    if let Some(ref g) = session.group {
        println!("group:      {} (rank: {})", g.name, g.rank);
    }
    if !session.session_id.is_empty() {
        println!("session_id: {}", session.session_id);
    }
    if session.pids.is_empty() {
        println!("pids:       (none)");
    } else {
        println!("pids:       {}", session.pids.iter().map(|p| p.to_string()).collect::<Vec<_>>().join(", "));
    }
    if !session.started.is_empty() {
        println!("started:    {}", session.started);
    }
    if !session.completed.is_empty() {
        println!("completed:  {}", session.completed);
    }
    if !session.retired_session_ids.is_empty() {
        println!("retired:    {} session{}", session.retired_session_ids.len(),
            if session.retired_session_ids.len() == 1 { "" } else { "s" });
        for r in &session.retired_session_ids {
            println!("  {}  {}", r.retired_at, r.reason);
        }
    }

    // ── Detail file sections ─────────────────────────────────────
    if let Some(ref contents) = detail_contents {
        let sections = crate::registry::parse_sections(contents);
        if sections.is_empty() {
            println!("\n📄 {} (no sections)", detail_path.display());
        } else {
            println!("\n📄 {}", detail_path.display());
            for (header, body) in &sections {
                // Count non-empty lines as a rough size hint
                let lines = body.lines().filter(|l| !l.trim().is_empty()).count();
                let hint = if lines > 0 {
                    format!(" ({} lines)", lines)
                } else {
                    String::new()
                };
                println!("   ## {}{}", header, hint);
            }
            println!("\n   `ccsm show {} --section <name>` to read one section", name);
        }
    } else {
        println!("\n💡 no detail file — create: cp {} {}",
            crate::registry::global_template_path(&ctx.id).display(),
            detail_path.display(),
        );
    }

    Ok(())
}



// ── Sequence subcommand ────────────────────────────────────────────────

/// `ccsm sequence -q <cmd> <args...> -q <cmd> <args...> ...`
///
/// Runs multiple mutations in a single lock/load/save cycle.
/// Each `-q` flag starts a new operation group.
fn run_sequence(args: &[String]) -> anyhow::Result<()> {
    // Split on "-q" markers into operation groups.
    let mut groups: Vec<Vec<String>> = Vec::new();
    let mut current: Vec<String> = Vec::new();
    let mut in_group = false;

    for arg in args {
        if arg == "-q" {
            if in_group && !current.is_empty() {
                groups.push(std::mem::take(&mut current));
            }
            in_group = true;
        } else if in_group {
            current.push(arg.clone());
        }
    }
    if in_group && !current.is_empty() {
        groups.push(current);
    }

    if groups.is_empty() {
        anyhow::bail!("{} expected at least one -q <command> ... group", ErrorCode::Invalid);
    }

    // Phase 1: Parse all operations (no lock — fail-fast on bad input)
    let ops: Vec<crate::sequence::SeqOp> = groups
        .iter()
        .map(|g| crate::sequence::SeqOp::parse(g))
        .collect::<anyhow::Result<Vec<_>>>()?;

    // Phase 2: Execute all operations in memory (single lock)
    let now = crate::registry::now_iso();
    let outputs = {
        let (mut reg, _lock) =
            crate::registry::WorkspaceRegistry::load_locked()?;

        let mut outputs = Vec::new();
        for op in &ops {
            let lines = crate::sequence::apply_op(&mut reg, op, &now)?;
            outputs.extend(lines);
        }

        reg.updated = now;
        reg.save()?;
        outputs
    }; // lock released

    // Phase 2.5: Sync detail files for scope/tag ops (after lock release — no registry I/O)
    for op in &ops {
        match op {
            crate::sequence::SeqOp::Scope { name, text } => {
                update_detail_section(name, "## Scope / Plan", text).ok();
            }
            crate::sequence::SeqOp::Tag { name, tags } => {
                update_detail_section(name, "## Tags", &tags.join(", ")).ok();
            }
            _ => {}
        }
    }

    // Phase 3: Print all output
    for line in &outputs {
        println!("{}", line);
    }

    Ok(())
}

// ── Note subcommand ────────────────────────────────────────────────────

/// Append a timestamped entry to `~/.ccsm/<id>/sessions/<name>.md` Progress Log.
/// With --cross <source>, prepends "CROSS-SESSION [source]: " to the note.
fn run_note(name: &str, text: &str, cross: Option<&str>) -> anyhow::Result<()> {
    let text = text.trim();
    if text.is_empty() {
        anyhow::bail!("{} note text is required. Usage: ccsm note <name> <text>", ErrorCode::Invalid);
    }

    let ctx = crate::registry::resolve_or_create_identity()?;

    // Verify session exists in registry
    let reg = crate::registry::WorkspaceRegistry::load()?;
    if !reg.sessions.iter().any(|s| s.name == name) {
        anyhow::bail!("{} no session named '{}'", ErrorCode::NoSession, name);
    }

    let detail_path = crate::registry::global_detail_path(&ctx.id, name);

    if !detail_path.exists() {
        // Auto-create detail file from registry data + template
        let session = reg.sessions.iter().find(|s| s.name == name).unwrap();
        let template_path = crate::registry::global_template_path(&ctx.id);
        // Ensure template exists
        if !template_path.exists() {
            let _ = std::fs::write(&template_path, crate::commands::doctor::TEMPLATE_CONTENT);
        }
        if template_path.exists()
            && let Ok(template) = std::fs::read_to_string(&template_path) {
                let status = session.status.to_string();
                let tags = if session.tags.is_empty() { "(none)".into() } else { session.tags.join(", ") };
                let pids = if session.pids.is_empty() { "(none)".into() } else { session.pids.iter().map(|p| p.to_string()).collect::<Vec<_>>().join(", ") };
                let populated = template
                    .replace("{{name}}", name)
                    .replace("{{goal}}", &session.goal)
                    .replace("{{status}}", &status)
                    .replace("{{scope}}", &session.scope)
                    .replace("{{tags}}", &tags)
                    .replace("{{session_id}}", &if session.session_id.is_empty() { "(auto — ccsm manages)".into() } else { session.session_id.clone() })
                    .replace("{{pids}}", &pids)
                    .replace("{{kind}}", "(auto)")
                    .replace("{{version}}", "(auto)")
                    .replace("{{waiting_for}}", "(none)")
                    .replace("{{dependencies}}", &if session.depends_on.is_empty() { "(none)".into() } else { session.depends_on.join(", ") })
                    .replace("{{now}}", &crate::registry::note_timestamp())
                    .replace("{{note}}", "Session detail file auto-created by ccsm note (was missing)");
                if let Some(parent) = detail_path.parent() {
                    let _ = std::fs::create_dir_all(parent);
                }
                let _ = std::fs::write(&detail_path, populated);
                eprintln!("  (auto-created missing detail file for '{}')", name);
            }
    }

    let contents = std::fs::read_to_string(&detail_path)?;
    let ts = crate::registry::note_timestamp();

    let formatted = match cross {
        Some(source) => format!("CROSS-SESSION [{}]: {}", source, text),
        None => text.to_string(),
    };

    let new_entry = format!("- [{}] {}\n", ts, formatted);
    let display = if cross.is_some() { &formatted } else { text };

    let new_contents = crate::registry::insert_note(&contents, &new_entry);
    std::fs::write(&detail_path, new_contents)?;

    action_msg("noted", name, &format!("[{}] {}", ts, display));
    Ok(())
}

// ── Helpers (now in registry.rs) ────────────────────────────────────────
// note_timestamp, days_to_date, is_leap, edit_distance, insert_note
// are imported from crate::registry.

// ── Doctor subcommand ──────────────────────────────────────────────────

/// Shared gate-check logic: returns Ok(()) if all hard checks pass,
/// Err with a human-readable message listing each failure otherwise.
/// Used by both `ccsm close` and the `ccsm complete` internal gate.
/// `ccsm note-check` — Stop-hook helper. If the in_progress session hasn't been
/// noted recently, emit a reminder. Time-based only — no git diff, no false positives
/// from stale uncommitted changes.
/// Auto-discovers the in_progress session. Silent when recently noted or no active session.
fn run_note_check() -> anyhow::Result<()> {
    use crate::registry::SessionStatus;

    let ctx = crate::registry::resolve_or_create_identity()?;

    // Find in_progress session. CCSM_SESSION env var is authoritative if set.
    let reg = crate::registry::WorkspaceRegistry::load()?;
    let session = {
        let env_session = std::env::var("CCSM_SESSION").ok();
        let s = if let Some(ref n) = env_session {
            reg.sessions.iter().find(|s| s.name == *n && s.status == SessionStatus::InProgress)
        } else {
            None
        };
        match s.or_else(|| reg.sessions.iter().find(|s| s.status == SessionStatus::InProgress)) {
            Some(s) => s,
            None => return Ok(()), // no active session → silent
        }
    };

    // Check detail file note recency
    let detail_path = crate::registry::global_detail_path(&ctx.id, &session.name);
    if !detail_path.exists() {
        return Ok(()); // no detail file → skip
    }

    let Ok(contents) = std::fs::read_to_string(&detail_path) else {
        return Ok(());
    };
    let sections = parse_sections(&contents);
    let pl_body = sections
        .iter()
        .find(|(h, _)| h.to_lowercase().contains("progress"))
        .map(|(_, b)| b.as_str())
        .unwrap_or("");

    // Find most recent `- [YYYY-MM-DD HH:MMZ]` entry
    let last_ts = pl_body
        .lines()
        .filter_map(|l| {
            let t = l.trim_start();
            if t.starts_with("- [") {
                t.get(3..19) // "YYYY-MM-DD HH:MMZ"
            } else {
                None
            }
        })
        .last();

    let stale = match last_ts {
        Some(ts) => {
            // Parse the timestamp and compare to current time
            // Format: "YYYY-MM-DD HH:MMZ"
            let now_secs = std::time::SystemTime::now()
                .duration_since(std::time::UNIX_EPOCH)
                .unwrap_or_default()
                .as_secs();
            let note_secs = parse_note_timestamp(ts).unwrap_or(0);
            now_secs.saturating_sub(note_secs) > 120 // > 2 min
        }
        None => true, // no notes at all
    };

    if stale {
        eprintln!(
            "\
⚡ If this turn modified/updated/changed anything, update the session detail.
  → ccsm note {} \"<what you changed and why>\"",
            session.name,
        );
    }

    Ok(())
}

/// Parse "YYYY-MM-DD HH:MMZ" into seconds since epoch.
fn parse_note_timestamp(s: &str) -> Option<u64> {
    let parts: Vec<&str> = s.split(&['-', ' ', ':', 'Z'][..]).collect();
    if parts.len() < 6 {
        return None;
    }
    let year: i64 = parts[0].parse().ok()?;
    let month: i64 = parts[1].parse().ok()?;
    let day: i64 = parts[2].parse().ok()?;
    let hour: i64 = parts[3].parse().ok()?;
    let min: i64 = parts[4].parse().ok()?;
    // Simple days-since-epoch (approximate, good enough for 60-min staleness check)
    let mut days = 0i64;
    for y in 1970..year {
        days += if is_leap_year(y) { 366 } else { 365 };
    }
    let mdays: [i64; 12] = if is_leap_year(year) {
        [31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31]
    } else {
        [31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31]
    };
    for m in 0..(month - 1) as usize {
        days += mdays[m];
    }
    days += day - 1;
    let secs = (days * 86400) as u64 + (hour as u64 * 3600) + (min as u64 * 60);
    Some(secs)
}

fn is_leap_year(y: i64) -> bool {
    (y % 4 == 0 && y % 100 != 0) || (y % 400 == 0)
}

fn run_gate_checks(name: &str) -> anyhow::Result<()> {
    let ctx = crate::registry::resolve_or_create_identity()?;
    let reg = crate::registry::WorkspaceRegistry::load()?;
    if !reg.sessions.iter().any(|s| s.name == name) {
        anyhow::bail!("{} no session named '{}'", ErrorCode::NoSession, name);
    }

    let detail_path = crate::registry::global_detail_path(&ctx.id, name);

    let mut failures: Vec<String> = Vec::new();

    if !detail_path.exists() {
        failures.push(format!(
            "  no detail file → cp {} {}",
            crate::registry::global_template_path(&ctx.id).display(),
            detail_path.display(),
        ));
        return Err(format_err(&failures, name));
    }

    let contents = std::fs::read_to_string(&detail_path)?;
    let sections = parse_sections(&contents);

    // Scope/Plan
    let scope_body = sections
        .iter()
        .find(|(h, _)| h.to_lowercase().contains("scope"))
        .map(|(_, b)| b.as_str())
        .unwrap_or("");
    if scope_body.trim().is_empty() || scope_body.contains("(fill in") {
        failures.push("  Scope/Plan is empty or still template".into());
    }

    // Tags
    let tags_body = sections
        .iter()
        .find(|(h, _)| h.to_lowercase() == "tags")
        .map(|(_, b)| b.as_str())
        .unwrap_or("");
    if tags_body.trim().is_empty() || tags_body.contains("(fill in") {
        failures.push("  Tags is empty or still template".into());
    }

    // Progress Log ≥ 2 entries
    let pl_body = sections
        .iter()
        .find(|(h, _)| h.to_lowercase().contains("progress"))
        .map(|(_, b)| b.as_str())
        .unwrap_or("");
    let note_count = pl_body
        .lines()
        .filter(|l| l.trim_start().starts_with("- ["))
        .count();
    if note_count < 2 {
        failures.push(format!(
            "  Progress Log has {} substantive entr{} (need ≥ 2)",
            note_count,
            if note_count == 1 { "y" } else { "ies" },
        ));
    }

    // Checklist gate: block if pending or blocked items exist
    let checklist_body = sections
        .iter()
        .find(|(h, _)| h.to_lowercase().contains("checklist"))
        .map(|(_, b)| b.as_str())
        .unwrap_or("");
    let cl_items = parse_checklist(checklist_body);
    let has_checklist_section = sections
        .iter()
        .any(|(h, _)| h.to_lowercase().contains("checklist"));
    let pending: Vec<_> = cl_items.iter().filter(|i| i.status == "pending").collect();
    let blocked: Vec<_> = cl_items.iter().filter(|i| i.status == "blocked").collect();
    if !pending.is_empty() {
        failures.push(format!(
            "  Checklist: {} pending item{}: {}",
            pending.len(),
            if pending.len() == 1 { "" } else { "s" },
            pending.iter().map(|i| format!("#{}. {}", i.index, i.text)).collect::<Vec<_>>().join(", "),
        ));
    }
    if !blocked.is_empty() {
        failures.push(format!(
            "  Checklist: {} blocked item{}: {}",
            blocked.len(),
            if blocked.len() == 1 { "" } else { "s" },
            blocked.iter().map(|i| format!("#{}. {}", i.index, i.text)).collect::<Vec<_>>().join(", "),
        ));
    }
    // Non-blocking nudge: session with real work but no checklist section
    if !has_checklist_section && note_count >= 2 {
        eprintln!(
            "💡 {} has {} progress notes but no checklist — `ccsm checklist {} --init` to add",
            name, note_count, name,
        );
    }

    if failures.is_empty() {
        Ok(())
    } else {
        Err(format_err(&failures, name))
    }
}

fn format_err(failures: &[String], name: &str) -> anyhow::Error {
    let mut msg = String::from("✗ gate failures:\n");
    for f in failures {
        msg.push_str(f);
        msg.push('\n');
    }
    msg.push_str(&format!(
        "  → edit ~/.ccsm/<id>/sessions/{}.md",
        name,
    ));
    anyhow::anyhow!("{}", msg)
}

/// `ccsm close <name>` — pre-completion gate. Run before `ccsm complete`.
///
/// **Hard checks** (exit non-zero on violation): detail file, scope, tags,
/// progress log, live session data.
/// **Self-review checklist** (always printed on pass).
fn run_close(name: &str) -> anyhow::Result<()> {
    run_gate_checks(name)?;

    println!(
        "\
🔍 Self-review:
  [ ] Tests pass?
  [ ] All changes committed and pushed?
  [ ] Scope fulfilled? Anything left undocumented?
  [ ] Dependencies resolved?
  [ ] Detail file tags and progress log are current?"
    );

    Ok(())
}

// ── Checklist subcommands ──────────────────────────────────────────────

/// Represents a single checklist item with its status.
#[derive(Debug)]
struct ChecklistItem {
    index: usize,
    status: String, // pending | done | skipped | blocked
    text: String,
}

const CHECKBOX_CHARS: &[(char, &str); 4] = &[
    (' ', "pending"),
    ('x', "done"),
    ('~', "skipped"),
    ('!', "blocked"),
];

fn status_to_char(status: &str) -> char {
    CHECKBOX_CHARS
        .iter()
        .find(|(_, s)| *s == status)
        .map(|(c, _)| *c)
        .unwrap_or(' ')
}

fn char_to_status(c: char) -> &'static str {
    CHECKBOX_CHARS
        .iter()
        .find(|(ch, _)| *ch == c)
        .map(|(_, s)| *s)
        .unwrap_or("pending")
}

/// Parse `## Checklist` section lines into `ChecklistItem`s.
fn parse_checklist(body: &str) -> Vec<ChecklistItem> {
    let mut items = Vec::new();
    for line in body.lines() {
        let trimmed = line.trim_start();
        // Match "- [X] text..." or "- [X]text..."
        if let Some(rest) = trimmed.strip_prefix("- [") {
            if rest.len() >= 2 {
                let ch = rest.chars().next().unwrap();
                let after_check = &rest[1..]; // skip the checkbox char
                let desc = after_check.trim_start_matches("] ").trim_start_matches(']');
                let status = char_to_status(ch);
                let idx = items.len() + 1;
                items.push(ChecklistItem {
                    index: idx,
                    status: status.to_string(),
                    text: desc.trim().to_string(),
                });
            }
        }
    }
    items
}

/// `ccsm checklist <name> [--init]` — list items or add section.
fn run_checklist(name: &str, init: bool) -> anyhow::Result<()> {
    let ctx = crate::registry::resolve_or_create_identity()?;
    let detail_path = crate::registry::global_detail_path(&ctx.id, name);

    if !detail_path.exists() {
        anyhow::bail!(
            "{} no detail file for session '{}' at {}", ErrorCode::Section,
            name,
            detail_path.display()
        );
    }

    // --init: add ## Checklist section if absent
    let mut contents = std::fs::read_to_string(&detail_path)?;
    let sections_before = parse_sections(&contents);
    let has_checklist = sections_before
        .iter()
        .any(|(h, _)| h.to_lowercase().contains("checklist"));

    if init {
        if has_checklist {
            println!("session '{}' already has a ## Checklist section", name);
            return Ok(());
        }
        let checklist_section = "\n## Checklist\n\n<!--\n  All items must be resolved before close gate allows completion.\n  Status: pending | done | skipped | blocked\n  Checkbox chars: - [ ] pending, - [x] done, - [~] skipped, - [!] blocked\n-->\n\n(no items yet — use `ccsm check <name> <text> --status pending` to add one)\n";
        contents.push_str(checklist_section);
        std::fs::write(&detail_path, &contents)?;
        println!("added ## Checklist section to {}", name);
        return Ok(());
    }

    let sections = sections_before;
    let checklist_body = sections
        .iter()
        .find(|(h, _)| h.to_lowercase().contains("checklist"))
        .map(|(_, b)| b.as_str())
        .unwrap_or("");

    let items = parse_checklist(checklist_body);
    if items.is_empty() {
        println!("(no checklist items)");
        return Ok(());
    }

    let _name_width = name.len().min(24);
    for item in &items {
        let icon = match item.status.as_str() {
            "done" => "✔",
            "skipped" => "⏭",
            "blocked" => "✗",
            _ => "·",
        };
        println!(
            "{:>3} [{}] {} {}",
            item.index, icon, item.text, dim_status(&item.status)
        );
    }

    // Summary line
    let counts = |s: &str| items.iter().filter(|i| i.status == s).count();
    println!(
        "{} items: {} pending, {} done, {} skipped, {} blocked",
        items.len(),
        counts("pending"),
        counts("done"),
        counts("skipped"),
        counts("blocked"),
    );
    Ok(())
}

fn dim_status(status: &str) -> String {
    format!("\x1b[2m({})\x1b[0m", status)
}

/// `ccsm check <name> <item> --status <pending|done|skipped|blocked>` — set item status,
/// or add a new item if no existing item matches.
fn run_check(name: &str, item_ref: &str, status: &str) -> anyhow::Result<()> {
    // Validate status
    if !CHECKBOX_CHARS.iter().any(|(_, s)| *s == status) {
        anyhow::bail!(
            "{} invalid status '{}' — use: pending, done, skipped, blocked",
            ErrorCode::BadStatus, status
        );
    }

    let ctx = crate::registry::resolve_or_create_identity()?;
    let detail_path = crate::registry::global_detail_path(&ctx.id, name);

    if !detail_path.exists() {
        anyhow::bail!(
            "{} no detail file for session '{}' at {}", ErrorCode::Section,
            name,
            detail_path.display()
        );
    }

    let mut contents = std::fs::read_to_string(&detail_path)?;
    let sections = parse_sections(&contents);
    let checklist_body = sections
        .iter()
        .find(|(h, _)| h.to_lowercase().contains("checklist"))
        .map(|(_, b)| b.as_str())
        .unwrap_or("");

    let items = parse_checklist(checklist_body);

    // ── Resolve item: numeric index, text match, or auto-add ──────────
    enum Action {
        Update(usize),            // existing item index (1-based)
        Append(String),           // new item text
    }

    let action = if items.is_empty() {
        // Empty checklist — treat item_ref as new item text
        Action::Append(item_ref.to_string())
    } else if let Ok(n) = item_ref.parse::<usize>() {
        if n < 1 || n > items.len() {
            // Out-of-range index → add as new
            Action::Append(item_ref.to_string())
        } else {
            Action::Update(n)
        }
    } else {
        // Substring match
        let matches: Vec<_> = items
            .iter()
            .filter(|i| i.text.to_lowercase().contains(&item_ref.to_lowercase()))
            .collect();
        if matches.is_empty() {
            // No match → add as new
            Action::Append(item_ref.to_string())
        } else if matches.len() > 1 {
            eprintln!("Multiple matches for '{}':", item_ref);
            for m in &matches {
                eprintln!("  {:>3}. {}", m.index, m.text);
            }
            anyhow::bail!("be more specific (use number or unique text)");
        } else {
            Action::Update(matches[0].index)
        }
    };

    match action {
        Action::Update(target_idx) => {
            let new_char = status_to_char(status);

            // Edit: update the checkbox character in the detail file
            let mut lines: Vec<String> = contents.lines().map(|s| s.to_string()).collect();
            let mut checklist_start: Option<usize> = None;
            let mut item_count = 0usize;

            // Find the ## Checklist section, then find the Nth checkbox line
            for (li, line) in lines.iter().enumerate() {
                if line.trim_start().starts_with("## ") {
                    if checklist_start.is_some() {
                        break; // next section — stop
                    }
                    if line.trim_start().to_lowercase().contains("checklist") {
                        checklist_start = Some(li);
                    }
                }
            }

            let start = checklist_start.unwrap_or(0);
            for li in start..lines.len() {
                let line = &lines[li];
                // Stop at next ## section
                if li > start && line.trim_start().starts_with("## ") {
                    break;
                }
                if line.trim_start().starts_with("- [") && line.trim_start().len() >= 4 {
                    item_count += 1;
                    if item_count == target_idx {
                        // Replace the checkbox character
                        let old = &lines[li];
                        let prefix_end = old.find("[").unwrap() + 1;
                        let prefix = &old[..prefix_end];
                        let rest = &old[prefix_end + 1..]; // skip old checkbox char
                        lines[li] = format!("{}{}{}", prefix, new_char, rest);
                        break;
                    }
                }
            }

            std::fs::write(&detail_path, lines.join("\n") + "\n")?;

            let target_item = &items[target_idx - 1];
            println!(
                "{} #{}. [{}] {} → {}",
                name, target_idx, icon_char(new_char), target_item.text, status,
            );
        }
        Action::Append(text) => {
            // Add a new checklist item. Create the section if it doesn't exist.
            let new_char = status_to_char(status);
            let has_section = sections
                .iter()
                .any(|(h, _)| h.to_lowercase().contains("checklist"));

            if !has_section {
                // Auto-create the section
                let checklist_section = "\n## Checklist\n\n<!--\n  All items must be resolved before close gate allows completion.\n  Status: pending | done | skipped | blocked\n  Checkbox chars: - [ ] pending, - [x] done, - [~] skipped, - [!] blocked\n-->\n";
                contents.push_str(checklist_section);
            }

            // Append the new item line
            let new_line = format!("- [{}] {}\n", new_char, text);
            contents.push_str(&new_line);
            std::fs::write(&detail_path, &contents)?;

            let idx = items.len() + 1;
            println!(
                "{} + #{}. [{}] {}",
                name, idx, icon_char(new_char), text,
            );
            if !has_section {
                eprintln!("  (## Checklist section auto-created)");
            }
        }
    }

    Ok(())
}

fn icon_char(c: char) -> &'static str {
    match c {
        'x' => "✔",
        '~' => "⏭",
        '!' => "✗",
        _ => "·",
    }
}

// ── Completions subcommand ─────────────────────────────────────────────

/// `ccsm completions <shell>` — generate shell completion script to stdout.
fn run_completions(shell: &str) -> anyhow::Result<()> {
    use clap::CommandFactory;
    use clap_complete::{Shell, generate};

    let mut cmd = Cli::command();
    let bin_name = "ccsm";

    match shell {
        "bash" => generate(Shell::Bash, &mut cmd, bin_name, &mut std::io::stdout()),
        "fish" => generate(Shell::Fish, &mut cmd, bin_name, &mut std::io::stdout()),
        "zsh" => generate(Shell::Zsh, &mut cmd, bin_name, &mut std::io::stdout()),
        other => {
            anyhow::bail!(
                "unknown shell '{}'. Supported: bash, fish, zsh",
                other
            );
        }
    }
    Ok(())
}

// ── InjectScope subcommand ───────────────────────────────────────────────

/// `ccsm inject-scope [--name <name>]` — output a `<system-reminder>` block
/// with the active session's goal and scope.  Designed for the SystemMessage
/// hook so the agent sees its current task constraints on every turn.
fn run_inject_scope(name: Option<&str>, consumer: Consumer) -> anyhow::Result<()> {
    let workspace = std::env::current_dir()?;
    let ctx = crate::registry::resolve_or_create_identity()?;
    let reg = crate::registry::WorkspaceRegistry::load()?;

    let session = match name {
        Some(n) => reg
            .sessions
            .iter()
            .find(|s| s.name == n)
            .ok_or_else(|| anyhow::anyhow!("no session named '{}'", n))?,
        None => {
            // CCSM_SESSION is injected at spawn time — it's the authoritative
            // source of identity. If absent/empty, there's no live session.
            let csm = std::env::var("CCSM_SESSION")
                .ok()
                .filter(|v| !v.is_empty());
            match csm {
                Some(ref n) => {
                    match reg.sessions.iter().find(|s| s.name == *n) {
                        Some(s) => s,
                        None => {
                            eprintln!(
                                "info: CCSM_SESSION={} not found in workspace — no live session",
                                n
                            );
                            return Ok(());
                        }
                    }
                }
                None => {
                    eprintln!("No live session! Please pick a session to continue.");
                    return Ok(());
                }
            }
        }
    };

    // Read checklist from detail file (mechanical injection — agent can't skip it)
    let detail_path = crate::registry::global_detail_path(&ctx.id, &session.name);
    let checklist_line = if detail_path.exists() {
        if let Ok(contents) = std::fs::read_to_string(&detail_path) {
            let sections = parse_sections(&contents);
            let cl_body = sections
                .iter()
                .find(|(h, _)| h.to_lowercase().contains("checklist"))
                .map(|(_, b)| b.as_str())
                .unwrap_or("");
            let items = parse_checklist(cl_body);
            if items.is_empty() {
                String::new()
            } else {
                let done = items.iter().filter(|i| i.status == "done").count();
                let pending = items.iter().filter(|i| i.status == "pending").count();
                let blocked = items.iter().filter(|i| i.status == "blocked").count();
                format!(
                    "CHECKLIST: {}/{} done{} — `ccsm checklist {}`",
                    done,
                    items.len(),
                    if blocked > 0 {
                        format!(" ({} blocked!)", blocked)
                    } else if pending > 0 {
                        format!(" ({} pending)", pending)
                    } else {
                        String::new()
                    },
                    session.name,
                )
            }
        } else {
            String::new()
        }
    } else {
        String::new()
    };

    let (open_tag, close_tag) = consumer.system_prompt_tags();
    println!("{open_tag}");
    println!("ACTIVE SESSION: {}", session.name);
    if !session.goal.is_empty() {
        println!("GOAL: {}", session.goal);
    }
    if !session.scope.is_empty() && !session.scope.contains("(fill in") {
        println!("SCOPE: {}", session.scope);
    }
    if !checklist_line.is_empty() {
        println!("{}", checklist_line);
    }

    // ── Branch check ──────────────────────────────────────────────
    if !session.branch.is_empty() {
        match std::process::Command::new("git")
            .args(["branch", "--show-current"])
            .current_dir(&workspace)
            .output()
        {
            Ok(output) => {
                let current = String::from_utf8_lossy(&output.stdout).trim().to_string();
                if current.is_empty() {
                    // Detached HEAD or not a git repo
                    println!("BRANCH: {} (detached HEAD — no active branch)", session.branch);
                } else if current == session.branch {
                    println!("BRANCH: {} ✓", session.branch);
                } else {
                    println!(
                        "BRANCH: {} (current: {}) ⚠️ MISMATCH — this session targets '{}'",
                        session.branch, current, session.branch
                    );
                }
            }
            Err(_) => {
                // git binary not available — skip branch check silently
            }
        }
    }

    // ── Worktree check ───────────────────────────────────────────
    let wt_path = crate::commands::worktree::worktree_path_for(&workspace, &session.name);
    if session.use_worktree || wt_path.is_dir() {
        println!("WORKTREE: {} — work inside this directory", wt_path.display());
    }

    // Extend constraint line if worktree is active
    let has_worktree = session.use_worktree || wt_path.is_dir();
    let constraint = if has_worktree {
        "CONSTRAINT: Work within this scope and worktree. If you need to do something outside it, ask first."
    } else {
        consumer.constraint_line()
    };
    println!("{constraint}");
    println!("{close_tag}");
    Ok(())
}

// ── GateCheck subcommand ──────────────────────────────────────────────────

/// `ccsm gate-check [--name <name>] [--strict]` — validate session readiness
/// before completing.  Designed for the Stop hook.
///
/// Checks: scope/goal presence, git diff surface, untracked files.
/// Exit 0 = pass, 1 = fail (for hook integration).
fn run_gate_check(name: Option<&str>, strict: bool) -> anyhow::Result<()> {
    let workspace = std::env::current_dir()?;
    let reg = crate::registry::WorkspaceRegistry::load()?;

    let session = match name {
        Some(n) => reg
            .sessions
            .iter()
            .find(|s| s.name == n)
            .ok_or_else(|| anyhow::anyhow!("no session named '{}'", n))?,
        None => {
            // CCSM_SESSION env var is injected at spawn time.
            let env_session = std::env::var("CCSM_SESSION").ok();
            if let Some(ref n) = env_session {
                if let Some(s) = reg.sessions.iter().find(|s| s.name == *n) {
                    s
                } else {
                    // CCSM_SESSION name not in this workspace's registry —
                    // fall through to in_progress scan.
                    let active: Vec<_> = reg
                        .sessions
                        .iter()
                        .filter(|s| s.status == crate::registry::SessionStatus::InProgress)
                        .collect();
                    match active.as_slice() {
                        [] => {
                            println!("GATE: NO_ACTIVE_SESSION — nothing to gate");
                            return Ok(());
                        }
                        [s] => *s,
                        multiple => {
                            println!("GATE: MULTIPLE_ACTIVE — {} in_progress sessions. Pass --name.", multiple.len());
                            for s in multiple {
                                println!("  - {}", s.name);
                            }
                            return Ok(());
                        }
                    }
                }
            } else {
                let active: Vec<_> = reg
                    .sessions
                    .iter()
                    .filter(|s| s.status == crate::registry::SessionStatus::InProgress)
                    .collect();
                match active.as_slice() {
                    [] => {
                        println!("GATE: NO_ACTIVE_SESSION — nothing to gate");
                        return Ok(());
                    }
                    [s] => *s,
                    multiple => {
                        println!("GATE: MULTIPLE_ACTIVE — {} in_progress sessions. Pass --name.", multiple.len());
                        for s in multiple {
                            println!("  - {}", s.name);
                        }
                        return Ok(());
                    }
                }
            }
        }
    };

    let mut fail = false;

    // ── Scope ──────────────────────────────────────────────────────────
    let scope_empty = session.scope.is_empty() || session.scope.contains("(fill in");
    if scope_empty {
        if strict {
            println!("GATE: FAIL — scope is empty or unfilled");
            fail = true;
        } else {
            println!(
                "GATE: WARN — scope is empty. Set: ccsm scope {} \"...\"",
                session.name
            );
        }
    }

    // ── Goal ──────────────────────────────────────────────────────────
    if session.goal.is_empty() {
        if strict {
            println!("GATE: FAIL — goal is empty");
            fail = true;
        } else {
            println!("GATE: WARN — goal is empty");
        }
    }

    // ── Git diff ──────────────────────────────────────────────────────
    if let Ok(output) = std::process::Command::new("git")
        .args(["diff", "--stat", "HEAD"])
        .current_dir(&workspace)
        .output()
        && !output.stdout.is_empty() {
            let stat = String::from_utf8_lossy(&output.stdout);
            println!("GATE: CHANGED FILES");
            let lines: Vec<&str> = stat.lines().collect();
            for line in lines.iter().take(20) {
                println!("  {}", line);
            }
            if lines.len() > 20 {
                println!("  ... and {} more lines", lines.len() - 20);
            }
        }

    // ── Untracked files ───────────────────────────────────────────────
    if let Ok(output) = std::process::Command::new("git")
        .args(["ls-files", "--others", "--exclude-standard"])
        .current_dir(&workspace)
        .output()
        && !output.stdout.is_empty() {
            let text = String::from_utf8_lossy(&output.stdout);
            let files: Vec<&str> = text.lines().collect();
            if !files.is_empty() {
                println!("GATE: UNTRACKED ({})", files.len());
                for f in files.iter().take(10) {
                    println!("  ? {}", f);
                }
            }
        }

    if fail {
        std::process::exit(1);
    }
    println!("GATE: PASS — '{}' is ready for review", session.name);
    Ok(())
}

// ── Setup subcommand ──────────────────────────────────────────────────

fn run_setup(bin_path: &str, consumer: Consumer) -> anyhow::Result<()> {
    // ── 0. Seed ~/.ccsm/<id>/config.toml if missing ───────────────
    seed_config();

    let copied = seed_skills(consumer);

    match consumer {
        Consumer::Pi => {
            println!("ccsm setup for Pi.");
            println!();
            println!("  ✓ .pi/extensions/ccsm/ — auto-discovered by Pi");
            println!("  ✓ 22 custom tools registered (ccsm_list, ccsm_new, ...)");
            println!("  ✓ Auto-injects active session scope into system prompt");
            println!("  ✓ Consumer auto-detection (--consumer pi or CCSM_CONSUMER=pi)");
            println!("  ✓ {} skill{} seeded to ~/.pi/agent/skills/", copied, if copied == 1 { "" } else { "s" });
            println!();
            println!("Usage: pi (tools auto-available) or ccsm --consumer pi <command>");
            Ok(())
        }
        Consumer::Claude => {
            use std::process::Command;
            let script = std::path::PathBuf::from(env!("CARGO_MANIFEST_DIR"))
                .join("scripts")
                .join("setup.sh");

            if !script.exists() {
                anyhow::bail!(
                    "setup script not found at {}\n\
                     (ccsm must be run from its source tree)",
                    script.display()
                );
            }

            println!("ccsm setup ({})\n", bin_path);
            let status = Command::new("bash")
                .arg(&script)
                .status()
                .map_err(|e| anyhow::anyhow!("failed to run setup script: {e}"))?;

            if !status.success() {
                anyhow::bail!("setup script exited with {status}");
            }
            println!("  ✓ {} skill{} seeded to ~/.claude/skills/", copied, if copied == 1 { "" } else { "s" });
            Ok(())
        }
        Consumer::OpenCode => {
            // Install ccsm plugin to opencode's global plugins directory
            let plugins_dir = std::path::PathBuf::from(
                std::env::var("HOME").unwrap_or_else(|_| ".".to_string()),
            )
            .join(".config")
            .join("opencode")
            .join("plugins");

            std::fs::create_dir_all(&plugins_dir)
                .context("creating opencode plugins directory")?;

            let plugin_src = std::path::PathBuf::from(env!("CARGO_MANIFEST_DIR"))
                .join("plugins")
                .join("opencode")
                .join("ccsm-plugin.ts");

            if !plugin_src.exists() {
                anyhow::bail!(
                    "plugin file not found at {}\n\
                     (ccsm must be run from its source tree)",
                    plugin_src.display()
                );
            }

            let plugin_dst = plugins_dir.join("ccsm-plugin.ts");
            std::fs::copy(&plugin_src, &plugin_dst)
                .with_context(|| format!("copying plugin to {}", plugin_dst.display()))?;

            println!("ccsm setup for OpenCode.");
            println!();
            println!("  ✓ Plugin installed to ~/.config/opencode/plugins/ccsm-plugin.ts");
            println!("  ✓ Injects session scope (goal + checklist) every LLM turn");
            println!("  ✓ Auto-links opencode sessions to ccsm registry");
            println!("  ✓ Consumer auto-detection (--consumer opencode or CCSM_CONSUMER=opencode)");
            println!("  ✓ {} skill{} seeded to ~/.config/opencode/skills/", copied, if copied == 1 { "" } else { "s" });
            println!();
            println!("Usage: opencode (plugin auto-loaded) or ccsm --consumer opencode <command>");
            println!("       Restart opencode if it's currently running.");
            Ok(())
        }
    }
}

/// Seed project skills from `.claude/skills/` to the consumer's global skills directory.
/// Returns count of skills seeded.
fn seed_skills(consumer: Consumer) -> u32 {
    let project_root = std::path::PathBuf::from(env!("CARGO_MANIFEST_DIR"));
    let src_skills = project_root.join(".claude").join("skills");
    if !src_skills.is_dir() {
        return 0;
    }

    let dst_skills = match consumer {
        Consumer::Claude => {
            std::path::PathBuf::from(
                std::env::var("HOME").unwrap_or_else(|_| ".".to_string()),
            )
            .join(".claude")
            .join("skills")
        }
        Consumer::Pi => {
            std::path::PathBuf::from(
                std::env::var("HOME").unwrap_or_else(|_| ".".to_string()),
            )
            .join(".pi")
            .join("agent")
            .join("skills")
        }
        Consumer::OpenCode => {
            // OpenCode discovers skills at ~/.config/opencode/skills/<name>/SKILL.md
            std::path::PathBuf::from(
                std::env::var("HOME").unwrap_or_else(|_| ".".to_string()),
            )
            .join(".config")
            .join("opencode")
            .join("skills")
        }
    };

    let mut copied = 0u32;
    if let Ok(entries) = std::fs::read_dir(&src_skills) {
        for entry in entries.flatten() {
            let src = entry.path();
            let name = src.file_name().unwrap_or_default();
            let dst = dst_skills.join(&name);
            if src.is_dir() && src.join("SKILL.md").exists() {
                std::fs::create_dir_all(&dst).ok();
                if std::fs::copy(src.join("SKILL.md"), dst.join("SKILL.md")).is_ok() {
                    copied += 1;
                }
            }
        }
    }
    copied
}

/// Seed `~/.ccsm/<id>/config.toml` if it doesn't exist yet.
/// Called during `ccsm setup` and can be reused as a standalone bootstrap.
fn seed_config() {
    let Ok(ctx) = crate::registry::resolve_or_create_identity() else { return };
    let config_path = crate::registry::global_config_path(&ctx.id);
    if config_path.exists() {
        return;
    }
    let default_config = r#"# ccsm project configuration
#
# Controls how ccsm enforces session discipline for agent workflows.
# The CLI reads this file directly — agents don't need to parse it.
#
# Built-in template types: feat, fix, research, chore

# Branch tracking policy: "required" | "optional" (default) | "disabled"
#   required  → ccsm new refuses without -b <branch>
#   optional  → -b is available but not mandatory
#   disabled  → -b is accepted but not enforced
branch_tracking = "optional"

# WIP guard — warn when creating a new session and this many are already in_progress
# Set to 0 to disable
wip_limit = 0

# Default template type when -c is used without a value (e.g. "feat")
# If unset, -c alone produces an empty checklist
# default_checklist_type = "feat"

# Custom checklist templates (override built-in defaults)
# [checklist_templates.feat]
# items = [
#   "Implementation plan drafted",
#   "Tests written for new functionality",
#   "Edge cases handled",
#   "Documentation updated",
# ]
"#;
    if let Some(parent) = config_path.parent() {
        let _ = std::fs::create_dir_all(parent);
    }
    match std::fs::write(&config_path, default_config) {
        Ok(()) => eprintln!("  ✓ {} created", config_path.display()),
        Err(e) => eprintln!("  ⚠ could not create {}: {e}", config_path.display()),
    }
}

/// `ccsm migrate-ccsm` — migrate ccsm workspace data from `.claude/` to `~/.ccsm/<id>/`.
/// Copies registry, detail files, group files, templates.
/// Leaves agent transcripts untouched (Claude keeps ~/.claude/projects/, Pi keeps ~/.pi/agent/sessions/).
fn run_migrate_ccsm(workspace: &std::path::Path, _home: &std::path::Path) -> anyhow::Result<()> {
    let ctx = crate::registry::resolve_or_create_identity()?;
    let claude = workspace.join(".claude");
    let ccsm = crate::registry::global_data_dir(&ctx.id);

    if !claude.exists() {
        println!("No .claude/ directory found — nothing to migrate.");
        return Ok(());
    }

    if !ccsm.exists() {
        std::fs::create_dir_all(&ccsm)?;
    }

    let mut copied = 0u32;
    let mut skipped = 0u32;

    // 1. sessions.json
    let src_json = claude.join("sessions.json");
    let dst_json = ccsm.join("sessions.json");
    if src_json.exists() && !dst_json.exists() {
        let contents = std::fs::read_to_string(&src_json)?;
        let mut reg: crate::registry::WorkspaceRegistry =
            serde_json::from_str(&contents).context("parsing legacy registry")?;
        for s in &mut reg.sessions {
            if s.consumer.is_empty() {
                s.consumer = "claude".into();
            }
        }
        reg.save()?;
        copied += 1;
    } else if dst_json.exists() {
        skipped += 1;
    }

    // 2. sessions/ detail files
    let src_sessions = claude.join("sessions");
    let dst_sessions = ccsm.join("sessions");
    if src_sessions.is_dir() {
        if !dst_sessions.exists() {
            std::fs::create_dir_all(&dst_sessions)?;
        }
        if let Ok(entries) = std::fs::read_dir(&src_sessions) {
            for entry in entries.flatten() {
                let src = entry.path();
                if src.extension().is_some_and(|e| e == "md") {
                    let name = src.file_stem().and_then(|n| n.to_str()).unwrap_or("");
                    let dst = dst_sessions.join(format!("{name}.md"));
                    if !dst.exists() {
                        std::fs::copy(&src, &dst)?;
                        copied += 1;
                    } else {
                        skipped += 1;
                    }
                }
            }
        }
    }

    // 3. session-group/ directory
    let src_group = claude.join("session-group");
    let dst_group = ccsm.join("session-group");
    if src_group.is_dir() {
        if !dst_group.exists() {
            std::fs::create_dir_all(&dst_group)?;
        }
        if let Ok(entries) = std::fs::read_dir(&src_group) {
            for entry in entries.flatten() {
                let src = entry.path();
                if src.extension().is_some_and(|e| e == "md") {
                    let name = src.file_stem().and_then(|n| n.to_str()).unwrap_or("");
                    let dst = dst_group.join(format!("{name}.md"));
                    if !dst.exists() {
                        std::fs::copy(&src, &dst)?;
                        copied += 1;
                    } else {
                        skipped += 1;
                    }
                }
            }
        }
    }

    // 4. session-detail-template.md
    let src_tpl = claude.join("session-detail-template.md");
    let dst_tpl = ccsm.join("session-detail-template.md");
    if src_tpl.exists() && !dst_tpl.exists() {
        std::fs::copy(&src_tpl, &dst_tpl)?;
        copied += 1;
    } else if dst_tpl.exists() {
        skipped += 1;
    }

    // 5. Strip stale worktree fields from destination registry (field removed in 0.16.0)
    if ccsm.join("sessions.json").exists() {
        use crate::registry::strip_stale_worktree;
        // Create a temporary WorkspaceIdentity with the same id
        let identity = crate::registry::WorkspaceIdentity {
            version: env!("CARGO_PKG_VERSION").to_string(),
            id: ctx.id.clone(),
        };
        if let Err(e) = strip_stale_worktree(&identity) {
            // Non-fatal — serde already ignores the field at runtime
            eprintln!("  (worktree cleanup skipped: {e})");
        } else {
            eprintln!("  stale worktree fields stripped from registry");
        }
    }

    println!("migrated to {}: {} copied, {} skipped", ccsm.display(), copied, skipped);
    Ok(())
}