tix-tracker 0.4.0

//! The planning registry: teams, cycles and milestones.
//!
//! Teams and cycles are names in `tix.toml` (`[teams.<label>]` /
//! `[cycles.<name>]`, FR-001/FR-002); milestones are markdown files in
//! `docs/milestones/` (`contracts/milestone-file-format.md`, FR-005). The
//! auto "Cycle N" counter lives in `[planning]` and only ever moves forward
//! (FR-003). All mutating operations persist through [`Config::save`], so a
//! planning round trip is just a `tix.toml` load/save pair (NFR-002/003).
//!
//! A `Planner` snapshot mirrors its backing config: re-load to observe
//! hand-edits.

use std::path::{Path, PathBuf};

use serde::{Deserialize, Serialize};

use crate::config::{Config, PlanningCycle, Team};
use crate::error::{Result, TixError};
use crate::model::Issue;
use crate::storage::Store;

#[derive(Debug, Clone, PartialEq, Eq)]
pub struct RolloverTarget {
    pub from_cycle: String,
    pub to_cycle: String,
    pub issues: Vec<u32>,
}

#[derive(Debug, Clone, PartialEq, Eq)]
pub struct Progress {
    pub done: usize,
    pub total: usize,
}

#[derive(Debug, Clone, PartialEq, Eq)]
pub struct RenameImpact {
    pub changed_issue_count: usize,
    pub issues: Vec<String>,
}

#[derive(Debug, Clone, PartialEq, Eq)]
pub struct Impact {
    pub referencing_issues: Vec<String>,
}

/// A milestone as materialized from its registry file. `description` is the
/// markdown body (the work summary); `file_name` is the registry filename
/// (`{created}-{slug}.md`, `contracts/milestone-file-format.md`). `created`
/// is the creation date (the filename prefix); `target_date` is the optional
/// `YYYY-MM-DD` due date (empty string when absent).
#[derive(Debug, Clone, PartialEq, Eq)]
pub struct Milestone {
    pub name: String,
    pub target_date: String,
    pub description: String,
    pub created: String,
    pub updated: String,
    pub file_name: String,
}

/// The YAML frontmatter of a milestone file (`contracts/milestone-file-format.md`).
#[derive(Debug, Clone, PartialEq, Eq, Default, Serialize, Deserialize)]
#[serde(default, deny_unknown_fields)]
struct MilestoneHead {
    name: String,
    #[serde(skip_serializing_if = "Option::is_none")]
    target_date: Option<String>,
    created: String,
    updated: String,
}

/// A working snapshot of the planning registry, bound to a repo root.
#[derive(Debug, Clone)]
pub struct Planner {
    root: PathBuf,
    config: Config,
}

impl Planner {
    /// Load the planning registry from `tix.toml` in the current directory,
    /// on the crate-wide assumption that commands run from the repo root.
    pub fn load() -> Result<Self> {
        Self::load_from(Path::new("tix.toml"))
    }

    /// Load the planning registry from an explicit config path.
    pub fn load_from(path: &Path) -> Result<Self> {
        let config = Config::load_with_warning(path, |token| {
            eprintln!(
                "warning: {} embeds a cleartext {} token; prefer an environment variable",
                path.display(),
                token
            );
        })?;
        let root = path
            .parent()
            .filter(|p| !p.as_os_str().is_empty())
            .map(Path::to_path_buf)
            .unwrap_or_else(|| PathBuf::from("."));
        Ok(Self::from_config(config, root))
    }

    /// Build a planner from an already-loaded config (used by `tix init` and
    /// tests). The config is not persisted here; mutators save on demand.
    pub fn from_config(config: Config, root: PathBuf) -> Self {
        Self { root, config }
    }

    /// The backing config this planner currently mirrors.
    pub fn config(&self) -> &Config {
        &self.config
    }

    /// The resolution this planner's board maps through.
    ///
    /// Built here rather than stored, because a `Planner` is a short-lived view
    /// over a config and caching it would be the per-object rebuild the service's
    /// "built once per config load" rule exists to avoid. The expensive part of a
    /// sweep is not building this — it is a handful of hash inserts per column —
    /// it is *not* re-deriving it per issue, and that is what callers do wrong.
    pub fn category_resolution(&self) -> crate::workflow::CategoryResolution {
        let board = self.config.default_config();
        crate::workflow::resolution(&self.config, board, "default")
    }

    /// Whether `issue` is complete, by the service's definition.
    ///
    /// Delegates rather than comparing `issue.status` to `done_column()` directly.
    /// The comparison it replaced was a **second** notion of completion: it read
    /// the board's `done_column` and ignored categories entirely, so a board whose
    /// `done_column` was `shipped` and whose `category_map` said something else
    /// answered differently from the category rule (C-004). The two agree on a
    /// board with no `category_map` — which is every existing configuration — and
    /// disagree on exactly the boards this mission exists to support.
    fn is_done_issue(&self, issue: &Issue) -> bool {
        let resolution = self.category_resolution();
        crate::workflow::is_completed(issue, &resolution)
    }

    /// The resolved milestones directory, relative to the repo root.
    pub fn milestones_dir(&self) -> PathBuf {
        self.root.join(self.config.milestones_dir())
    }

    /// Persist the current config snapshot to `tix.toml`.
    fn save(&self) -> Result<()> {
        self.config.save(&self.root.join("tix.toml"))
    }

    /// Look up a team by label.
    pub fn team(&self, label: &str) -> Option<&Team> {
        self.config.teams.get(label)
    }

    /// Look up a cycle by name.
    pub fn cycle(&self, name: &str) -> Option<&PlanningCycle> {
        self.config.cycles.get(name)
    }

    /// Cycle names in declaration order.
    pub fn cycle_names(&self) -> Vec<String> {
        self.config.cycles.keys().cloned().collect()
    }

    pub fn is_overdue(issue: &Issue, today: &str) -> bool {
        issue.due_date.as_deref().is_some_and(|due| due < today)
    }

    pub fn cycle_expired(cycle: &PlanningCycle, today: &str) -> bool {
        cycle.due_date.as_deref().is_some_and(|due| due < today)
    }

    pub fn successor<'a>(
        &'a self,
        cycle: &str,
        today: &str,
    ) -> Option<(&'a str, &'a PlanningCycle)> {
        self.config
            .cycles
            .iter()
            .filter(|(name, c)| {
                *name != cycle && c.start_date.as_deref().is_some_and(|s| s >= today)
            })
            .min_by(|a, b| {
                let by_start = a.1.start_date.cmp(&b.1.start_date);
                if by_start == std::cmp::Ordering::Equal {
                    a.0.cmp(b.0)
                } else {
                    by_start
                }
            })
            .map(|(name, c)| (name.as_str(), c))
    }

    pub fn overdue_batch(&self, store: &Store, today: &str) -> Vec<Issue> {
        store
            .list()
            .unwrap_or_default()
            .into_iter()
            .filter(|issue| !self.is_done_issue(issue) && Self::is_overdue(issue, today))
            .collect()
    }

    pub fn rollover_plan(&self, store: &Store, today: &str) -> Vec<RolloverTarget> {
        let mut out = Vec::new();
        for (from_cycle, cycle) in &self.config.cycles {
            if !Self::cycle_expired(cycle, today) {
                continue;
            }
            let Some((to_cycle, _successor)) = self.successor(from_cycle, today) else {
                continue;
            };
            let issues = store
                .list()
                .unwrap_or_default()
                .into_iter()
                .filter(|issue| {
                    issue
                        .cycles
                        .as_ref()
                        .is_some_and(|cycles| cycles.iter().any(|c| c == from_cycle))
                        && !self.is_done_issue(issue)
                        && !issue
                            .cycles
                            .as_ref()
                            .is_some_and(|cycles| cycles.iter().any(|c| c == to_cycle))
                })
                .map(|issue| issue.number)
                .collect::<Vec<_>>();
            if !issues.is_empty() {
                out.push(RolloverTarget {
                    from_cycle: from_cycle.clone(),
                    to_cycle: to_cycle.to_string(),
                    issues,
                });
            }
        }
        out
    }

    pub fn cycle_progress(&self, store: &Store, name: &str) -> Progress {
        let mut done = 0usize;
        let mut total = 0usize;
        for issue in store.list().unwrap_or_default() {
            if issue
                .cycles
                .as_ref()
                .is_some_and(|cycles| cycles.iter().any(|cycle| cycle == name))
            {
                total += 1;
                if self.is_done_issue(&issue) {
                    done += 1;
                }
            }
        }
        Progress { done, total }
    }

    pub fn milestone_progress(&self, store: &Store, name: &str) -> Progress {
        let mut done = 0usize;
        let mut total = 0usize;
        for issue in store.list().unwrap_or_default() {
            if issue
                .milestones
                .as_ref()
                .is_some_and(|milestones| milestones.iter().any(|milestone| milestone == name))
            {
                total += 1;
                if self.is_done_issue(&issue) {
                    done += 1;
                }
            }
        }
        Progress { done, total }
    }

    /// The next auto cycle name. Skips forward past any existing `Cycle N`
    /// keys and permanently bumps `[planning].cycle_number` one past the
    /// returned name, per the seed's `cycle_number = 1` successor semantics.
    /// The bump is persisted by the mutator that calls this.
    pub fn next_cycle_name(&mut self) -> String {
        let mut n = self.config.planning.cycle_number;
        loop {
            let candidate = format!("Cycle {n}");
            if !self.config.cycles.contains_key(&candidate) {
                self.config.planning.cycle_number = n + 1;
                return candidate;
            }
            n += 1;
        }
    }

    /// Create a named or auto cycle. An explicit name must not collide with
    /// the current auto-counter successor (`Cycle {cycle_number}`), a config
    /// error, so hand-authored keys and generated ones never overlap.
    pub fn add_cycle(&mut self, name: Option<String>) -> Result<String> {
        let name = match name {
            Some(name) => name,
            None => self.next_cycle_name(),
        };
        let name = name.trim().to_string();
        if name.is_empty() {
            return Err(TixError::InvalidInput(
                "cycle name must not be blank".into(),
            ));
        }
        if self.config.cycles.contains_key(&name) {
            return Err(TixError::InvalidInput(format!(
                "cycle `{name}` already exists"
            )));
        }
        if let Some(auto) = self.current_auto_name()
            && name == auto
        {
            return Err(TixError::Config(format!(
                "cycle `{name}` collides with the auto-cycle counter; pick another name or let it auto-increment"
            )));
        }
        self.config
            .cycles
            .insert(name.clone(), PlanningCycle::default());
        self.save()?;
        Ok(name)
    }

    /// Rename a cycle, moving its declaration order slot and rebasing
    /// `default_cycle` when it pointed at the old name.
    pub fn rename_cycle(&mut self, old: &str, new: &str) -> Result<()> {
        let new = new.trim().to_string();
        if old == new {
            return Ok(());
        }
        if !self.config.cycles.contains_key(old) {
            return Err(TixError::InvalidInput(format!(
                "cycle `{old}` does not exist"
            )));
        }
        if new.is_empty() {
            return Err(TixError::InvalidInput(
                "cycle name must not be blank".into(),
            ));
        }
        if self.config.cycles.contains_key(&new) {
            return Err(TixError::InvalidInput(format!(
                "cycle `{new}` already exists"
            )));
        }
        if let Some(auto) = self.current_auto_name()
            && new == auto
        {
            return Err(TixError::Config(format!(
                "cycle `{new}` collides with the auto-cycle counter"
            )));
        }
        let cycle = self
            .config
            .cycles
            .shift_remove(old)
            .expect("existence checked above");
        self.config.cycles.insert(new.clone(), cycle);
        if self.config.planning.default_cycle.as_deref() == Some(old) {
            self.config.planning.default_cycle = Some(new);
        }
        self.save()?;
        Ok(())
    }

    pub fn delete_impact(&self, store: &Store, name: &str) -> Result<Impact> {
        let mut referencing_issues = Vec::new();
        for issue in store.list()? {
            if issue
                .cycles
                .as_ref()
                .is_some_and(|cycles| cycles.iter().any(|cycle| cycle == name))
            {
                referencing_issues.push(issue.filename);
            }
        }
        Ok(Impact { referencing_issues })
    }

    pub fn rename_cycle_cascade(
        &mut self,
        store: &Store,
        old: &str,
        new: &str,
    ) -> Result<RenameImpact> {
        let new = new.trim();
        if new.is_empty() {
            return Err(TixError::InvalidInput(
                "cycle name must not be blank".into(),
            ));
        }
        if !self.config.cycles.contains_key(old) {
            return Err(TixError::InvalidInput(format!(
                "cycle `{old}` does not exist"
            )));
        }
        if old != new && self.config.cycles.contains_key(new) {
            return Err(TixError::InvalidInput(format!(
                "cycle `{new}` already exists"
            )));
        }
        let mut issues = Vec::new();
        for mut issue in store.list()? {
            let Some(cycles) = issue.cycles.as_mut() else {
                continue;
            };
            let mut changed = false;
            for cycle in cycles.iter_mut() {
                if cycle == old {
                    *cycle = new.to_string();
                    changed = true;
                }
            }
            if changed {
                issue.bump_updated();
                store.update(&issue.filename, &issue)?;
                issues.push(issue.filename);
            }
        }
        self.rename_cycle(old, new)?;
        Ok(RenameImpact {
            changed_issue_count: issues.len(),
            issues,
        })
    }

    pub fn set_cycle_fields(
        &mut self,
        name: &str,
        description: Option<&str>,
        start_date: Option<&str>,
        due_date: Option<&str>,
    ) -> Result<()> {
        let cycle = self
            .config
            .cycles
            .get_mut(name)
            .ok_or_else(|| TixError::InvalidInput(format!("cycle `{name}` does not exist")))?;

        if let Some(description) = description {
            let description = description.trim();
            cycle.description = if description.is_empty() {
                None
            } else {
                Some(description.to_string())
            };
        }
        if let Some(start_date) = start_date {
            let start_date = start_date.trim();
            if start_date.is_empty() {
                cycle.start_date = None;
            } else {
                if !crate::model::validate_date(start_date) {
                    return Err(TixError::InvalidInput(format!(
                        "start_date `{start_date}` must be a `YYYY-MM-DD` calendar date"
                    )));
                }
                cycle.start_date = Some(start_date.to_string());
            }
        }
        if let Some(due_date) = due_date {
            let due_date = due_date.trim();
            if due_date.is_empty() {
                cycle.due_date = None;
            } else {
                if !crate::model::validate_date(due_date) {
                    return Err(TixError::InvalidInput(format!(
                        "due_date `{due_date}` must be a `YYYY-MM-DD` calendar date"
                    )));
                }
                cycle.due_date = Some(due_date.to_string());
            }
        }
        self.config.validate()?;
        self.save()
    }

    pub fn delete_cycle(&mut self, name: &str) -> Result<()> {
        if self.config.cycles.shift_remove(name).is_none() {
            return Err(TixError::InvalidInput(format!(
                "cycle `{name}` does not exist"
            )));
        }
        if self.config.planning.default_cycle.as_deref() == Some(name) {
            self.config.planning.default_cycle = None;
        }
        self.save()
    }

    /// Add a member to a team, creating the team when absent. Duplicate
    /// members and blank inputs are rejected.
    pub fn add_team_member(&mut self, label: &str, member: &str) -> Result<()> {
        let label = label.trim();
        let member = member.trim();
        if label.is_empty() {
            return Err(TixError::InvalidInput(
                "team label must not be blank".into(),
            ));
        }
        if member.is_empty() {
            return Err(TixError::InvalidInput("member must not be blank".into()));
        }
        let team = self.config.teams.entry(label.to_string()).or_default();
        if team.members.iter().any(|m| m == member) {
            return Err(TixError::InvalidInput(format!(
                "`{member}` is already a member of team `{label}`"
            )));
        }
        team.members.push(member.to_string());
        self.config.validate()?;
        self.save()?;
        Ok(())
    }

    /// All milestones, sorted by filename (which sorts by `target_date` then
    /// slug — the registry is a directory listing, never a stored list).
    pub fn list_milestones(&self) -> Result<Vec<Milestone>> {
        let dir = self.milestones_dir();
        if !dir.exists() {
            return Ok(Vec::new());
        }
        let mut milestones = Vec::new();
        let mut read_error = None;
        for entry in std::fs::read_dir(&dir)? {
            let Ok(entry) = entry else { continue };
            if entry.path().extension().and_then(|e| e.to_str()) != Some("md") {
                continue;
            }
            let file_name = entry.file_name();
            let Some(file_name) = file_name.to_str().map(str::to_string) else {
                continue;
            };
            match std::fs::read_to_string(entry.path()) {
                Ok(contents) => {
                    if let Some((head, body)) = Self::parse_milestone_file(&contents) {
                        milestones.push(Self::milestone_from(head, file_name, body));
                    }
                }
                Err(e) => read_error = Some(e),
            }
        }
        if let Some(e) = read_error {
            return Err(TixError::Io(e));
        }
        milestones.sort_by(|a, b| a.file_name.cmp(&b.file_name));
        Ok(milestones)
    }

    /// Milestone names in listing order.
    pub fn milestone_names(&self) -> Result<Vec<String>> {
        Ok(self
            .list_milestones()?
            .into_iter()
            .map(|m| m.name)
            .collect())
    }

    /// Look up a milestone by its frontmatter `name`.
    pub fn milestone(&self, name: &str) -> Result<Milestone> {
        for entry in std::fs::read_dir(self.milestones_dir())? {
            let Ok(entry) = entry else { continue };
            let file_name = entry.file_name();
            let Some(file_name) = file_name.to_str().map(str::to_string) else {
                continue;
            };
            let Ok(contents) = std::fs::read_to_string(entry.path()) else {
                continue;
            };
            if let Some((head, body)) = Self::parse_milestone_file(&contents)
                && head.name == name
            {
                return Ok(Self::milestone_from(head, file_name, body));
            }
        }
        Err(TixError::NotFound(format!("milestone `{name}`")))
    }

    /// Create a milestone registry file. The filename is
    /// `{created}-{slug}.md` where `created` is today's date; an optional
    /// `target_date` is stored in the frontmatter and must be a valid
    /// `YYYY-MM-DD` calendar date when given (FR-007). The markdown body is
    /// the optional description. Refuses to overwrite an existing file.
    pub fn create_milestone_file(
        &self,
        name: &str,
        target_date: Option<&str>,
        description: Option<&str>,
    ) -> Result<PathBuf> {
        let name = name.trim().to_string();
        if name.is_empty() {
            return Err(TixError::InvalidInput(
                "milestone name must not be blank".into(),
            ));
        }
        if let Some(date) = target_date
            && !crate::model::validate_date(date)
        {
            return Err(TixError::InvalidInput(format!(
                "target_date `{date}` must be a `YYYY-MM-DD` calendar date"
            )));
        }
        let today = crate::model::today();
        let dir = self.milestones_dir();
        let file_name = format!("{today}-{}.md", crate::slug::slugify(&name));
        let path = dir.join(file_name);
        if path.exists() {
            return Err(TixError::InvalidInput(format!(
                "`{}` already exists",
                path.display()
            )));
        }
        std::fs::create_dir_all(&dir)?;
        let head = MilestoneHead {
            name: name.clone(),
            target_date: target_date.map(str::to_string),
            created: today.clone(),
            updated: today,
        };
        let frontmatter = serde_yaml::to_string(&head)
            .map_err(|e| TixError::Parse(format!("cannot serialize milestone frontmatter: {e}")))?;
        let body = body_for(description);
        std::fs::write(&path, format!("---\n{frontmatter}---\n\n{body}"))?;
        Ok(path)
    }

    /// Rename a milestone file, keeping the `created` date prefix, bumping
    /// `updated` and rebasing the frontmatter `name`; the body is preserved
    /// verbatim (the cascade back into referencing issues is FR-009/IC-08
    /// work that lives in the issue layer, not the registry).
    pub fn rename_milestone_file(&self, old: &Milestone, new_name: &str) -> Result<PathBuf> {
        let new_name = new_name.trim();
        if new_name.is_empty() {
            return Err(TixError::InvalidInput(
                "milestone name must not be blank".into(),
            ));
        }
        let dir = self.milestones_dir();
        let old_path = dir.join(&old.file_name);
        let contents = std::fs::read_to_string(&old_path).map_err(|e| {
            if e.kind() == std::io::ErrorKind::NotFound {
                TixError::NotFound(format!("milestone file `{}`", old.file_name))
            } else {
                TixError::Io(e)
            }
        })?;
        let Some((_fm, body)) = Self::split_frontmatter(&contents) else {
            return Err(TixError::Parse(format!("cannot parse `{}`", old.file_name)));
        };
        let prefix = if old.created.is_empty() {
            crate::model::today()
        } else {
            old.created.clone()
        };
        let new_file_name = format!("{prefix}-{}.md", crate::slug::slugify(new_name));
        let new_path = dir.join(new_file_name);
        if new_path.exists() {
            return Err(TixError::InvalidInput(format!(
                "`{}` already exists",
                new_path.display()
            )));
        }
        let head = MilestoneHead {
            name: new_name.to_string(),
            target_date: (!old.target_date.is_empty()).then(|| old.target_date.clone()),
            created: prefix,
            updated: crate::model::today(),
        };
        let frontmatter = serde_yaml::to_string(&head)
            .map_err(|e| TixError::Parse(format!("cannot serialize milestone frontmatter: {e}")))?;
        std::fs::write(&new_path, format!("---\n{frontmatter}---\n\n{body}"))?;
        std::fs::remove_file(&old_path)?;
        Ok(new_path)
    }

    pub fn milestone_delete_impact(&self, store: &Store, name: &str) -> Result<Impact> {
        let mut referencing_issues = Vec::new();
        for issue in store.list()? {
            if issue
                .milestones
                .as_ref()
                .is_some_and(|milestones| milestones.iter().any(|milestone| milestone == name))
            {
                referencing_issues.push(issue.filename);
            }
        }
        Ok(Impact { referencing_issues })
    }

    pub fn rename_milestone_cascade(
        &self,
        store: &Store,
        old: &Milestone,
        new_name: &str,
    ) -> Result<RenameImpact> {
        let _ = self.rename_milestone_file(old, new_name)?;
        let mut issues = Vec::new();
        for mut issue in store.list()? {
            let Some(milestones) = issue.milestones.as_mut() else {
                continue;
            };
            let mut changed = false;
            for milestone in milestones.iter_mut() {
                if milestone == &old.name {
                    *milestone = new_name.to_string();
                    changed = true;
                }
            }
            if changed {
                issue.bump_updated();
                store.update(&issue.filename, &issue)?;
                issues.push(issue.filename);
            }
        }
        Ok(RenameImpact {
            changed_issue_count: issues.len(),
            issues,
        })
    }

    pub fn update_milestone(
        &self,
        name: &str,
        target_date: Option<&str>,
        description: Option<&str>,
    ) -> Result<()> {
        let milestone = self.milestone(name)?;
        let next_target = match target_date {
            Some(value) => {
                let value = value.trim();
                if value.is_empty() {
                    None
                } else {
                    if !crate::model::validate_date(value) {
                        return Err(TixError::InvalidInput(format!(
                            "target_date `{value}` must be a `YYYY-MM-DD` calendar date"
                        )));
                    }
                    Some(value.to_string())
                }
            }
            None => (!milestone.target_date.is_empty()).then_some(milestone.target_date.clone()),
        };
        let body = description.unwrap_or(&milestone.description);
        let head = MilestoneHead {
            name: milestone.name.clone(),
            target_date: next_target,
            created: milestone.created.clone(),
            updated: crate::model::today(),
        };
        let frontmatter = serde_yaml::to_string(&head)
            .map_err(|e| TixError::Parse(format!("cannot serialize milestone frontmatter: {e}")))?;
        let path = self.milestones_dir().join(&milestone.file_name);
        std::fs::write(
            path,
            format!("---\n{frontmatter}---\n\n{}", body_for(Some(body))),
        )?;
        Ok(())
    }

    pub fn delete_milestone(&self, name: &str) -> Result<String> {
        let milestone = self.milestone(name)?;
        let path = self.milestones_dir().join(&milestone.file_name);
        std::fs::remove_file(path)?;
        Ok(milestone.file_name)
    }

    /// The auto successor name the counter currently implies.
    fn current_auto_name(&self) -> Option<String> {
        Some(format!("Cycle {}", self.config.planning.cycle_number))
    }

    fn milestone_from(head: MilestoneHead, file_name: String, body: &str) -> Milestone {
        Milestone {
            name: head.name,
            target_date: head.target_date.unwrap_or_default(),
            description: body.trim_end().to_string(),
            created: head.created,
            updated: head.updated,
            file_name,
        }
    }

    /// Split `contents` into its frontmatter text and the body (everything
    /// after the closing `---` delimiter line, with the single structural
    /// blank line consumed), reusing the same delimiter rules as
    /// [`crate::model::Issue::parse`].
    fn split_frontmatter(contents: &str) -> Option<(&str, &str)> {
        let rest = contents.strip_prefix("---\n")?;
        let mut current = rest;
        let mut fm_len = 0usize;
        loop {
            let line_end = current.find('\n').map(|i| i + 1).unwrap_or(current.len());
            let content = current[..line_end]
                .strip_suffix('\n')
                .unwrap_or(&current[..line_end]);
            if content == "---" {
                break;
            }
            fm_len += line_end;
            current = &current[line_end..];
            if current.is_empty() {
                return None;
            }
        }
        let mut body = &rest[fm_len..];
        body = body.strip_prefix("---\n").unwrap_or(body);
        if let Some(after) = body.strip_prefix('\n') {
            body = after;
        }
        Some((&rest[..fm_len], body))
    }

    /// Parse a milestone file into its head and body suffix. `None` when the
    /// file has no valid frontmatter block (skipped, not an error).
    fn parse_milestone_file(contents: &str) -> Option<(MilestoneHead, &str)> {
        let (frontmatter, body) = Self::split_frontmatter(contents)?;
        let head: MilestoneHead = serde_yaml::from_str(frontmatter).ok()?;
        Some((head, body))
    }
}

/// Render a milestone file body from its optional description: the trimmed
/// paragraph plus a single trailing newline (empty when no description).
fn body_for(description: Option<&str>) -> String {
    match description {
        Some(text) if !text.trim().is_empty() => format!("{}\n", text.trim_end()),
        _ => String::new(),
    }
}

#[cfg(test)]
mod tests {
    /// The delegation to `workflow::is_completed` is **load-bearing only on a
    /// board that declares a `category_map`**, and that is asserted here rather
    /// than assumed.
    ///
    /// Reverting `is_done_issue` to its previous body — comparing the status to
    /// `done_column()` — left the whole suite **green**. The two rules agree on
    /// every board without a `category_map`, which is every existing configuration,
    /// so the delegation was unverified: a refactor that looked correct and proved
    /// nothing. This fixture is the configuration where they disagree, reached
    /// through the public `overdue_batch`, which filters on completion.
    ///
    /// The board: `shipped` is the `done_column` but maps to `active`, and
    /// `archived` is what actually completes. Under the old rule an issue in
    /// `shipped` was done and therefore not overdue; under the category rule it is
    /// active work and therefore still overdue. `archived` is the mirror image.
    #[test]
    fn completion_follows_the_category_not_the_done_column() {
        use crate::config::{BoardConfiguration, OrderBy};
        use indexmap::IndexMap;
        let tmp = tempfile::TempDir::new().unwrap();
        let issues_dir = tmp.path().join("docs").join("issues");
        std::fs::create_dir_all(&issues_dir).unwrap();

        // Absolute, not the config default: `Store` resolves `issues_dir` against
        // the process working directory, so a relative path reads some other
        // repository's issues and the batch comes back empty.
        let mut config = Config {
            issues_dir: issues_dir.clone(),
            ..Default::default()
        };
        let mut category_map = IndexMap::new();
        category_map.insert("wip".to_string(), "active".to_string());
        category_map.insert("shipped".to_string(), "active".to_string());
        category_map.insert("archived".to_string(), "completed".to_string());
        config.kanban.configurations.insert(
            "default".to_string(),
            BoardConfiguration {
                columns: vec![
                    "wip".to_string(),
                    "shipped".to_string(),
                    "archived".to_string(),
                ],
                done_column: Some("shipped".to_string()),
                category_map,
                hidden_columns: vec![],
                show_mismatch: false,
                wrap_titles: true,
                title_lines: 3,
                card_order: vec![],
                order_by: OrderBy::CreatedAtDesc,
            },
        );
        // `archived` is the only completing column, so load accepts the mapping.
        config
            .validate()
            .expect("the fixture must be a valid config");

        let write = |name: &str, number: u32, status: &str, due: &str| {
            std::fs::write(
                issues_dir.join(name),
                format!(
                    "---\nnumber: {number}\ntitle: \"{status}\"\nstatus: \"{status}\"\n\
                     labels: []\npriority: \"medium\"\ndue_date: \"{due}\"\n\
                     created: 2026-01-01\nupdated: 2026-01-01\n---\n\nBody.\n"
                ),
            )
            .unwrap();
        };
        write("2026-01-01-wip.md", 1, "wip", "2026-01-02");
        write("2026-01-01-shipped.md", 2, "shipped", "2026-01-02");
        write("2026-01-01-archived.md", 3, "archived", "2026-01-02");

        let store = crate::storage::Store::open(&config).unwrap();
        let planner = Planner::from_config(config, tmp.path().to_path_buf());
        let today = "2026-06-01";
        let mut overdue: Vec<u32> = planner
            .overdue_batch(&store, today)
            .iter()
            .map(|i| i.number)
            .collect();
        // Sorted before comparing: `overdue_batch` does not promise an order, and
        // the claim here is about *membership*. The first version of this test
        // asserted a fixed order and failed on `[2, 1]` — the right two issues in
        // an order nothing specifies.
        overdue.sort_unstable();

        assert_eq!(
            overdue,
            vec![1, 2],
            "`wip` and `shipped` are both `active`, so both are still overdue; \
             `archived` is the only completing column"
        );
        // And the specific claim: `shipped` is the done_column, so the old
        // comparison would have dropped it from the batch.
        assert!(
            overdue.contains(&2),
            "an issue in the `done_column` is not complete when its category is \
             `active` — the category is the only completion definition (C-004)"
        );
    }

    use super::*;
    use crate::model::today;
    use std::fs;
    use tempfile::TempDir;

    fn planner_in(tmp: &TempDir) -> Planner {
        Planner::from_config(Config::default(), tmp.path().to_path_buf())
    }

    #[test]
    fn milestones_dir_resolves_configured_and_default() {
        let tmp = TempDir::new().unwrap();
        let p = planner_in(&tmp);
        assert_eq!(p.milestones_dir(), tmp.path().join("docs/milestones"));

        let mut cfg = Config {
            milestones_dir: Some(PathBuf::from("tasks/milestones")),
            ..Config::default()
        };
        let p = Planner::from_config(cfg.clone(), tmp.path().to_path_buf());
        assert_eq!(p.milestones_dir(), tmp.path().join("tasks/milestones"));
        cfg.milestones_dir = None;
        let p = Planner::from_config(cfg, tmp.path().to_path_buf());
        assert_eq!(p.milestones_dir(), tmp.path().join("docs/milestones"));
    }

    #[test]
    fn auto_cycle_names_skip_existing_and_bump_counter() {
        let tmp = TempDir::new().unwrap();
        let mut p = planner_in(&tmp);
        assert_eq!(p.next_cycle_name(), "Cycle 1");
        assert_eq!(p.config.planning.cycle_number, 2);
        assert_eq!(p.add_cycle(None).unwrap(), "Cycle 2");
        assert_eq!(p.next_cycle_name(), "Cycle 3");
    }

    #[test]
    fn add_cycle_rejects_duplicates_and_counter_collision() {
        let tmp = TempDir::new().unwrap();
        let mut p = planner_in(&tmp);
        p.config
            .cycles
            .insert("Cycle 1".into(), PlanningCycle::default());
        let err = p.add_cycle(Some("Cycle 1".into())).unwrap_err();
        assert!(matches!(err, TixError::InvalidInput(_)), "got {err:?}");
        assert!(err.to_string().contains("already exists"));
        // Counter is 1 and "Cycle 1" exists as a hand-authored key → config error.
        let err = p.add_cycle(Some("Cycle 1".into())).unwrap_err();
        assert!(matches!(err, TixError::InvalidInput(_)), "got {err:?}");
    }

    #[test]
    fn add_cycle_collision_with_current_counter_is_config_error() {
        let tmp = TempDir::new().unwrap();
        let mut p = planner_in(&tmp);
        let err = p.add_cycle(Some("Cycle 1".into())).unwrap_err();
        assert!(matches!(err, TixError::Config(_)), "got {err:?}");
        assert!(err.to_string().contains("collides"));
    }

    #[test]
    fn rename_cycle_moves_slot_and_rebases_default() {
        let tmp = TempDir::new().unwrap();
        let mut p = planner_in(&tmp);
        p.config
            .cycles
            .insert("Old".into(), PlanningCycle::default());
        p.config.planning.default_cycle = Some("Old".into());
        p.rename_cycle("Old", "New").unwrap();
        assert!(p.cycle("Old").is_none());
        assert!(p.cycle("New").is_some());
        assert_eq!(p.config.planning.default_cycle.as_deref(), Some("New"));
        let err = p.rename_cycle("Old", "X").unwrap_err();
        assert!(matches!(err, TixError::InvalidInput(_)), "got {err:?}");
    }

    #[test]
    fn add_team_member_creates_and_dedupes() {
        let tmp = TempDir::new().unwrap();
        let mut p = planner_in(&tmp);
        p.add_team_member("platform", "@alice").unwrap();
        assert_eq!(p.team("platform").unwrap().members, ["@alice"]);
        let err = p.add_team_member("platform", "@alice").unwrap_err();
        assert!(matches!(err, TixError::InvalidInput(_)), "got {err:?}");
        assert!(err.to_string().contains("already a member"));
        let err = p.add_team_member("", "@alice").unwrap_err();
        assert!(matches!(err, TixError::InvalidInput(_)), "got {err:?}");
    }

    #[test]
    fn milestone_file_writes_contract_format_and_reads_back() {
        let tmp = TempDir::new().unwrap();
        let p = planner_in(&tmp);
        let today = today();
        let path = p
            .create_milestone_file("Ship V1", Some("2026-12-01"), Some("The launch"))
            .unwrap();
        // Filename prefix is the creation date, not target_date.
        assert_eq!(
            path.file_name().unwrap(),
            format!("{today}-ship-v1.md").as_str()
        );
        let raw = fs::read_to_string(&path).unwrap();
        assert!(raw.starts_with("---\n"));
        assert!(raw.contains("target_date: 2026-12-01"));
        assert!(raw.contains(&format!("created: {today}")));
        assert!(raw.contains(&format!("updated: {today}")));
        let ms = p.milestone("Ship V1").unwrap();
        assert_eq!(ms.target_date, "2026-12-01");
        assert_eq!(ms.description, "The launch");
        assert_eq!(ms.created, today);
        assert_eq!(ms.file_name, format!("{today}-ship-v1.md"));
        let names = p.milestone_names().unwrap();
        assert_eq!(names, ["Ship V1"]);
    }

    #[test]
    fn milestone_without_target_date_omits_the_key() {
        let tmp = TempDir::new().unwrap();
        let p = planner_in(&tmp);
        let path = p.create_milestone_file("Backlog", None, None).unwrap();
        let raw = fs::read_to_string(&path).unwrap();
        assert!(
            !raw.contains("target_date"),
            "no target_date expected:\n{raw}"
        );
        assert!(raw.contains("name: Backlog"));
        let ms = p.milestone("Backlog").unwrap();
        assert_eq!(ms.target_date, "");
        assert_eq!(ms.description, "");
    }

    #[test]
    fn milestone_rejects_invalid_dates_and_overwrites() {
        let tmp = TempDir::new().unwrap();
        let p = planner_in(&tmp);
        let err = p
            .create_milestone_file("X", Some("2026-13-99"), None)
            .unwrap_err();
        assert!(matches!(err, TixError::InvalidInput(_)), "got {err:?}");
        assert!(err.to_string().contains("target_date"));
        p.create_milestone_file("X", None, None).unwrap();
        let err = p.create_milestone_file("X", None, None).unwrap_err();
        assert!(matches!(err, TixError::InvalidInput(_)), "got {err:?}");
        assert!(err.to_string().contains("already exists"));
    }

    #[test]
    fn rename_milestone_file_preserves_body_and_bumps_updated() {
        let tmp = TempDir::new().unwrap();
        let p = planner_in(&tmp);
        let today = today();
        p.create_milestone_file("Alpha", None, Some("old body text"))
            .unwrap();
        let old = p.milestone("Alpha").unwrap();
        let new_path = p.rename_milestone_file(&old, "Beta").unwrap();
        assert_eq!(
            new_path.file_name().unwrap(),
            format!("{today}-beta.md").as_str()
        );
        assert!(p.milestone("Alpha").is_err());
        let beta = p.milestone("Beta").unwrap();
        assert_eq!(beta.created, today);
        assert_eq!(beta.updated, today);
        assert_eq!(beta.description, "old body text");
        let raw = fs::read_to_string(&new_path).unwrap();
        assert!(raw.contains("name: Beta"), "renamed frontmatter:\n{raw}");
        assert!(
            !raw.contains("name: Alpha"),
            "old name must be rebased:\n{raw}"
        );
        assert!(
            raw.contains("old body text"),
            "body preserved verbatim:\n{raw}"
        );
    }

    #[test]
    fn list_milestones_is_empty_before_directory_exists() {
        let tmp = TempDir::new().unwrap();
        let p = planner_in(&tmp);
        assert!(p.list_milestones().unwrap().is_empty());
        assert!(p.milestone("nope").is_err());
    }

    #[test]
    fn team_and_cycle_index_maps_preserve_insertion_order() {
        let tmp = TempDir::new().unwrap();
        let mut p = planner_in(&tmp);
        p.config.cycles.insert("C".into(), PlanningCycle::default());
        p.config.cycles.insert("A".into(), PlanningCycle::default());
        assert_eq!(p.cycle_names(), ["C", "A"]);
        let final_cfg = Config::load_with_warning(&p.root.join("tix.toml"), |_| {});
        assert!(final_cfg.is_err(), "nothing persisted, nothing to load");
    }
}