imp-core 0.1.0

//! Canonical single-unit mana worker runtime.
//!
//! Provides the reusable substrate for executing one mana unit:
//! loading the unit via canonical mana-core APIs, assembling execution
//! context (task prompt, prefill, dependency summaries), and reporting
//! structured outcomes.
//!
//! This module is consumed by:
//! - `imp run <unit-id>` (imp-cli) — the preferred single-unit CLI path
//! - legacy `mana run` compatibility flows — transitional dispatch into imp workers
//! - imp's native mana tool — the first-class orchestration UX
//!
//! ## Architecture
//!
//! ```text
//! imp native mana tool        = first-class orchestration UX
//! imp run (this module)       = canonical single-unit worker runtime
//! legacy mana run compatibility = transitional parallel dispatch into imp workers
//! ```

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

use crate::contracts::evidence::{ArtifactKind, ArtifactRef, VerifierResult, VerifierStatus};
pub use crate::contracts::worker::{WorkerAssignment, WorkerAttempt, WorkerResult, WorkerStatus};
use imp_llm::ThinkingLevel;
use mana_core::api;
use mana_core::ops::close::{CloseOpts, CloseOutcome, VerifyFailureResult};
use mana_core::ops::verify as mana_verify;

use crate::context_prefill::{self, AssembledContext, FileSpec, PrefillConfig};
use crate::imp_session::{ImpSession, SessionChoice, SessionOptions};
use crate::mana_prompt_context;
use crate::system_prompt::{Attempt, Dependency, Fact, TaskContext};
use crate::tools::LuaToolLoader;

// ---------------------------------------------------------------------------
// Shared contract re-exports
// ---------------------------------------------------------------------------

// Canonical worker assignment/outcome vocabulary lives in imp-owned contracts
// until mana also needs a versioned shared protocol crate.
// Re-export it here to keep current imp-core call sites stable during migration.

// ---------------------------------------------------------------------------
// Loading
// ---------------------------------------------------------------------------

/// Load a worker assignment from a mana unit using canonical mana-core APIs.
///
/// This replaces the ad hoc markdown-scanning `load_mana_unit()` that lived
/// in imp-cli. It uses `mana_core::api::get_unit()` for canonical resolution
/// and `mana_core::discovery::find_mana_dir()` for `.mana/` discovery.
pub fn load_assignment(
    cwd: &Path,
    unit_id: &str,
) -> Result<WorkerAssignment, Box<dyn std::error::Error>> {
    load_assignment_with_mana_dir(cwd, unit_id, None)
}

/// Load a worker assignment with an explicit mana dir override.
pub fn load_assignment_with_mana_dir(
    cwd: &Path,
    unit_id: &str,
    mana_dir_override: Option<&Path>,
) -> Result<WorkerAssignment, Box<dyn std::error::Error>> {
    let mana_dir = match mana_dir_override {
        Some(dir) => dir.to_path_buf(),
        None => mana_core::discovery::find_mana_dir(cwd).map_err(|e| {
            format!(
                "Could not find .mana directory while walking up from {}: {e}",
                cwd.display()
            )
        })?,
    };

    let workspace_root = mana_dir
        .parent()
        .map(Path::to_path_buf)
        .unwrap_or_else(|| cwd.to_path_buf());

    let unit = api::get_unit(&mana_dir, unit_id)
        .map_err(|e| format!("Failed to load mana unit {unit_id}: {e}"))?;

    // Read the unit file body (description may be in the markdown body
    // after the frontmatter, which mana-core merges into unit.description).
    // mana-core's Unit already handles frontmatter+body merging in from_file(),
    // so unit.description contains the full combined text.
    let description = unit.description.clone().unwrap_or_default();

    // Also read the markdown body from the unit file for any content
    // after the frontmatter that mana-core stores separately.
    let unit_path = mana_core::discovery::find_unit_file(&mana_dir, unit_id).ok();
    let body = unit_path.as_ref().and_then(|path| {
        let content = std::fs::read_to_string(path).ok()?;
        let body = extract_markdown_body(&content)?;
        if body.trim().is_empty() {
            None
        } else {
            Some(body)
        }
    });

    let full_description = match body {
        Some(body_text) if !description.is_empty() => {
            format!("{}\n\n{}", description.trim(), body_text.trim())
        }
        Some(body_text) => body_text.trim().to_string(),
        None => description,
    };

    let attempts = unit
        .attempt_log
        .iter()
        .map(|record| WorkerAttempt {
            number: record.num,
            outcome: format!("{:?}", record.outcome).to_lowercase(),
            summary: record.notes.clone().unwrap_or_default(),
        })
        .collect();

    // Extract explicit file references from paths field.
    let files: Vec<String> = Vec::new(); // Unit doesn't have a separate `files` field in mana-core

    Ok(WorkerAssignment {
        id: unit.id.clone(),
        title: unit.title.clone(),
        description: full_description,
        acceptance: unit.acceptance.clone(),
        verify: unit.verify.clone(),
        notes: unit.notes.clone(),
        decisions: unit.decisions.clone(),
        dependencies: unit.dependencies.clone(),
        paths: unit.paths.clone(),
        files,
        attempts,
        workspace_root,
        model: unit.model.clone(),
    })
}

// ---------------------------------------------------------------------------
// Context assembly
// ---------------------------------------------------------------------------

/// Build a `TaskContext` from a worker assignment for system prompt Layer 5.
fn derive_task_constraints(assignment: &WorkerAssignment) -> Vec<String> {
    let mut constraints = Vec::new();

    if !assignment.paths.is_empty() || !assignment.files.is_empty() {
        constraints.push(
            "Scope changes to the declared file/path hints unless a clear dependency forces broader edits."
                .to_string(),
        );
    }

    if assignment.verify.is_some() {
        constraints.push(
            "Treat the verify command as the primary completion gate for this task.".to_string(),
        );
    } else {
        constraints.push(
            "Do not claim completion until the acceptance criteria are concretely satisfied."
                .to_string(),
        );
    }

    if !assignment.dependencies.is_empty() {
        constraints.push(
            "Respect dependency context and avoid reworking already-completed dependency work unless required."
                .to_string(),
        );
    }

    if !assignment.decisions.is_empty() {
        constraints.push(
            "Treat unresolved decisions as real constraints; either resolve them explicitly or work around them honestly."
                .to_string(),
        );
    }

    constraints
}

pub fn build_task_context(assignment: &WorkerAssignment) -> TaskContext {
    let description = assignment.description.trim().to_string();

    let notes = assignment
        .notes
        .as_deref()
        .map(str::trim)
        .filter(|n| !n.is_empty())
        .map(str::to_string);

    let dependencies = if assignment.dependencies.is_empty() {
        Vec::new()
    } else {
        // Try to load dependency summaries from the index
        let mana_dir = assignment.workspace_root.join(".mana");
        match api::load_index(&mana_dir) {
            Ok(index) => assignment
                .dependencies
                .iter()
                .map(|dep_id| {
                    let entry = index.units.iter().find(|e| e.id == *dep_id);
                    Dependency {
                        name: dep_id.clone(),
                        status: entry
                            .map(|e| e.status.to_string())
                            .unwrap_or_else(|| "unknown".to_string()),
                        detail: entry
                            .map(|e| e.title.clone())
                            .unwrap_or_else(|| "not found in active index".to_string()),
                    }
                })
                .collect(),
            Err(_) => assignment
                .dependencies
                .iter()
                .map(|dep_id| Dependency {
                    name: dep_id.clone(),
                    status: "unknown".to_string(),
                    detail: "dependency status unavailable".to_string(),
                })
                .collect(),
        }
    };

    let mut context_paths = assignment.paths.clone();
    for file in &assignment.files {
        if !context_paths.iter().any(|path| path == file) {
            context_paths.push(file.clone());
        }
    }

    TaskContext {
        title: assignment.title.clone(),
        description,
        acceptance: assignment.acceptance.clone(),
        verify: assignment.verify.clone(),
        notes,
        attempts: assignment
            .attempts
            .iter()
            .map(|a| Attempt {
                number: a.number,
                outcome: a.outcome.clone(),
                summary: a.summary.clone(),
            })
            .collect(),
        dependencies,
        decisions: assignment.decisions.clone(),
        context_paths,
        constraints: derive_task_constraints(assignment),
    }
}

pub struct WorkerRunOptions {
    pub cwd: PathBuf,
    pub model_override: Option<imp_llm::Model>,
    pub model: Option<String>,
    pub provider: Option<String>,
    pub api_key: Option<String>,
    pub thinking: Option<ThinkingLevel>,
    pub max_turns: Option<u32>,
    pub max_tokens: Option<u32>,
    pub system_prompt: Option<String>,
    pub no_tools: bool,
    pub mana_dir_override: Option<PathBuf>,
    pub defer_verify: bool,
    pub lua_loader: Option<LuaToolLoader>,
}

pub struct PreparedWorkerRun {
    pub assignment: WorkerAssignment,
    pub task_context: TaskContext,
    pub facts: Vec<Fact>,
    pub prefilled_files: Vec<PathBuf>,
    pub prefill_warnings: Vec<String>,
    pub estimated_prefill_tokens: usize,
    pub prompt: String,
    pub session: ImpSession,
    defer_verify: bool,
}

pub struct WorkerRunOutcome {
    pub assignment: WorkerAssignment,
    pub result: WorkerResult,
    pub verify_passed: Option<bool>,
    pub closed_after_verify: bool,
    pub prefilled_files: Vec<PathBuf>,
    pub prefill_warnings: Vec<String>,
    pub estimated_prefill_tokens: usize,
    pub verify_output: Option<String>,
    pub verifier_result: Option<VerifierResult>,
}

struct MappedCloseOutcome {
    status: WorkerStatus,
    summary: String,
    error: Option<String>,
    closed_after_verify: bool,
    verify_output: Option<String>,
    verifier_result: Option<VerifierResult>,
}

pub async fn prepare_worker_run(
    assignment: WorkerAssignment,
    options: WorkerRunOptions,
) -> Result<PreparedWorkerRun, Box<dyn std::error::Error>> {
    let assembled = assemble_prefill(&assignment, &options.cwd);
    let task_context = build_task_context(&assignment);
    let facts = options
        .mana_dir_override
        .clone()
        .or_else(|| mana_prompt_context::nearest_mana_dir(&options.cwd))
        .map(|mana_dir| {
            mana_prompt_context::load_task_prompt_context(&mana_dir, &task_context.context_paths)
                .facts
        })
        .unwrap_or_default();

    let session_options = SessionOptions {
        cwd: options.cwd,
        model_override: options.model_override,
        model: options.model,
        provider: options.provider,
        api_key: options.api_key,
        thinking: options.thinking,
        max_turns: options.max_turns,
        max_tokens: options.max_tokens,
        system_prompt: options.system_prompt,
        no_tools: options.no_tools,
        session: SessionChoice::InMemory,
        task: Some(task_context.clone()),
        facts: facts.clone(),
        context_prefill: assembled.messages,
        lua_loader: options.lua_loader,
        ..Default::default()
    };

    let session = ImpSession::create(session_options)
        .await
        .map_err(|e| -> Box<dyn std::error::Error> { Box::new(e) })?;
    let prompt = build_task_prompt(&assignment);

    Ok(PreparedWorkerRun {
        assignment,
        task_context,
        facts,
        prefilled_files: assembled.included_files,
        prefill_warnings: assembled.warnings,
        estimated_prefill_tokens: assembled.estimated_tokens,
        prompt,
        session,
        defer_verify: options.defer_verify,
    })
}

pub async fn finalize_worker_run(
    prepared: PreparedWorkerRun,
) -> Result<WorkerRunOutcome, Box<dyn std::error::Error>> {
    let PreparedWorkerRun {
        assignment,
        prefilled_files,
        prefill_warnings,
        estimated_prefill_tokens,
        session,
        defer_verify,
        ..
    } = prepared;

    let model = Some(session.model().meta.id.clone());
    let tool_count = session
        .session_manager()
        .get_active_messages()
        .iter()
        .filter(|message| matches!(message, imp_llm::Message::ToolResult(_)))
        .count();
    let turns = session
        .session_manager()
        .get_active_messages()
        .iter()
        .filter(|message| matches!(message, imp_llm::Message::Assistant(_)))
        .count();

    let batch_verify = defer_verify || std::env::var("MANA_BATCH_VERIFY").is_ok();
    let mut verify_passed = None;
    let mut closed_after_verify = false;
    let mut status = if assignment
        .verify
        .as_deref()
        .map(str::trim)
        .filter(|verify| !verify.is_empty())
        .is_some()
    {
        WorkerStatus::AwaitingVerify
    } else {
        WorkerStatus::Completed
    };
    let mut summary_override = None;
    let mut verify_output = None;
    let mut verifier_result = None;
    let mut error = None;

    if !batch_verify {
        if let Some(verify) = assignment
            .verify
            .as_deref()
            .map(str::trim)
            .filter(|verify| !verify.is_empty())
        {
            let (passed, output) =
                run_verify_command(&assignment.id, verify, &assignment.workspace_root).await?;
            verify_passed = Some(passed);
            verify_output = output;
            if passed {
                let mapped = close_unit_after_verify(&assignment)?;
                status = mapped.status;
                error = mapped.error;
                closed_after_verify = mapped.closed_after_verify;
                summary_override = Some(mapped.summary);
                verify_output = mapped.verify_output.or(verify_output);
                verifier_result = mapped.verifier_result;
            } else {
                status = WorkerStatus::Failed;
                error = Some(format!("Verify command failed: {verify}"));
            }
        }
    }

    let summary = summary_override.or_else(|| {
        Some(match status {
            WorkerStatus::Completed => {
                if closed_after_verify {
                    format!(
                        "Unit {} completed and closed after verify pass.",
                        assignment.id
                    )
                } else if verify_passed == Some(true) {
                    format!("Unit {} completed successfully.", assignment.id)
                } else {
                    format!("Unit {} completed.", assignment.id)
                }
            }
            WorkerStatus::AwaitingVerify => {
                format!("Unit {} completed and is awaiting verify.", assignment.id)
            }
            WorkerStatus::Failed => {
                if verify_passed == Some(false) {
                    format!("Unit {} finished but verify failed.", assignment.id)
                } else {
                    format!("Unit {} failed.", assignment.id)
                }
            }
            WorkerStatus::Blocked => format!("Unit {} is blocked.", assignment.id),
            WorkerStatus::Cancelled => format!("Unit {} was cancelled.", assignment.id),
        })
    });

    let result = WorkerResult {
        unit_id: assignment.id.clone(),
        status,
        summary,
        error,
        tool_count,
        turns,
        tokens: None,
        cost: None,
        model,
    };

    Ok(WorkerRunOutcome {
        assignment,
        result,
        verify_passed,
        closed_after_verify,
        prefilled_files,
        prefill_warnings,
        estimated_prefill_tokens,
        verify_output,
        verifier_result,
    })
}

fn close_unit_after_verify(
    assignment: &WorkerAssignment,
) -> Result<MappedCloseOutcome, Box<dyn std::error::Error>> {
    let mana_dir = assignment.workspace_root.join(".mana");
    let outcome = api::close_unit(
        &mana_dir,
        &assignment.id,
        CloseOpts {
            reason: None,
            force: false,
            defer_verify: false,
        },
    )?;
    Ok(map_close_outcome(&assignment.id, outcome))
}

fn map_close_outcome(unit_id: &str, outcome: CloseOutcome) -> MappedCloseOutcome {
    match outcome {
        CloseOutcome::Closed(_) => MappedCloseOutcome {
            status: WorkerStatus::Completed,
            summary: format!("Unit {unit_id} completed and closed after verify pass."),
            error: None,
            closed_after_verify: true,
            verify_output: None,
            verifier_result: None,
        },
        CloseOutcome::DeferredVerify { .. } => MappedCloseOutcome {
            status: WorkerStatus::AwaitingVerify,
            summary: format!("Unit {unit_id} completed and is awaiting verify."),
            error: None,
            closed_after_verify: false,
            verify_output: None,
            verifier_result: None,
        },
        CloseOutcome::VerifyFailed(result) => map_verify_failed_close_outcome(unit_id, result),
        CloseOutcome::RejectedByHook { unit_id } => MappedCloseOutcome {
            status: WorkerStatus::Blocked,
            summary: format!("Unit {unit_id} is blocked by a pre-close hook."),
            error: Some("Pre-close hook rejected close.".to_string()),
            closed_after_verify: false,
            verify_output: None,
            verifier_result: None,
        },
        CloseOutcome::FeatureRequiresHuman { unit_id, title, .. } => MappedCloseOutcome {
            status: WorkerStatus::Blocked,
            summary: format!("Unit {unit_id} requires human review to close feature '{title}'."),
            error: Some("Feature unit requires human close.".to_string()),
            closed_after_verify: false,
            verify_output: None,
            verifier_result: None,
        },
        CloseOutcome::CircuitBreakerTripped {
            unit_id,
            total_attempts,
            max,
            ..
        } => MappedCloseOutcome {
            status: WorkerStatus::Blocked,
            summary: format!(
                "Unit {unit_id} is blocked because the circuit breaker tripped ({total_attempts} >= {max})."
            ),
            error: Some("Circuit breaker tripped during close.".to_string()),
            closed_after_verify: false,
            verify_output: None,
            verifier_result: None,
        },
        CloseOutcome::MergeConflict { files, .. } => MappedCloseOutcome {
            status: WorkerStatus::Blocked,
            summary: format!(
                "Unit {unit_id} is blocked by merge conflicts during close ({} file(s)).",
                files.len()
            ),
            error: Some(format!("Merge conflict during close: {}", files.join(", "))),
            closed_after_verify: false,
            verify_output: None,
            verifier_result: None,
        },
        CloseOutcome::VerifyFrozenViolation { unit_id, .. } => MappedCloseOutcome {
            status: WorkerStatus::Blocked,
            summary: format!("Unit {unit_id} is blocked because the verify command changed since claim."),
            error: Some("Verify frozen violation during close.".to_string()),
            closed_after_verify: false,
            verify_output: None,
            verifier_result: None,
        },
    }
}

fn map_verify_failed_close_outcome(
    unit_id: &str,
    result: VerifyFailureResult,
) -> MappedCloseOutcome {
    let summary = if result.timed_out {
        format!("Unit {unit_id} failed during close because verify timed out.")
    } else {
        format!("Unit {unit_id} failed during close because verify failed.")
    };
    let error = if result.output.trim().is_empty() {
        Some(format!(
            "Verify command failed during close: {}",
            result.verify_command
        ))
    } else {
        Some(format!(
            "Verify command failed during close: {}\n{}",
            result.verify_command, result.output
        ))
    };

    let verifier_result = build_verify_failure_verifier_result(unit_id, &result);

    MappedCloseOutcome {
        status: WorkerStatus::Failed,
        summary,
        error,
        closed_after_verify: false,
        verify_output: Some(result.output),
        verifier_result: Some(verifier_result),
    }
}

fn build_verify_failure_verifier_result(
    unit_id: &str,
    result: &VerifyFailureResult,
) -> VerifierResult {
    let mut artifact_refs = Vec::new();
    if !result.output.trim().is_empty() {
        artifact_refs.push(ArtifactRef {
            artifact_id: format!("{unit_id}:verify-output"),
            kind: ArtifactKind::VerifyOutput,
            locator: format!("verify-output://{unit_id}"),
            run_id: None,
            unit_id: Some(unit_id.to_string()),
            stage: Some("verify".to_string()),
        });
    }

    VerifierResult {
        verifier_name: "unit.verify".to_string(),
        status: VerifierStatus::Failed,
        command: Some(result.verify_command.clone()),
        exit_code: result.exit_code,
        summary: Some(if result.timed_out {
            "verify timed out".to_string()
        } else {
            "verify failed".to_string()
        }),
        artifact_refs,
        started_at: None,
        finished_at: None,
        run_id: None,
        unit_id: Some(unit_id.to_string()),
    }
}

pub async fn run_worker_assignment(
    assignment: WorkerAssignment,
    options: WorkerRunOptions,
) -> Result<WorkerRunOutcome, Box<dyn std::error::Error>> {
    let mut prepared = prepare_worker_run(assignment, options).await?;
    prepared
        .session
        .prompt(&prepared.prompt)
        .await
        .map_err(|e| -> Box<dyn std::error::Error> { Box::new(e) })?;
    prepared
        .session
        .wait()
        .await
        .map_err(|e| -> Box<dyn std::error::Error> { Box::new(e) })?;
    finalize_worker_run(prepared).await
}

async fn run_verify_command(
    unit_id: &str,
    verify: &str,
    cwd: &Path,
) -> Result<(bool, Option<String>), Box<dyn std::error::Error>> {
    let verify = verify.trim();
    let working_dir = cwd.to_path_buf();
    let verify_cmd = verify.to_string();
    let mana_dir = cwd.join(".mana");
    let timeout_secs = if mana_dir.exists() {
        match api::get_unit(&mana_dir, unit_id) {
            Ok(unit) => {
                let config = mana_core::config::Config::load_with_extends(&mana_dir).ok();
                unit.effective_verify_timeout(config.as_ref().and_then(|c| c.verify_timeout))
            }
            Err(_) => None,
        }
    } else {
        None
    };

    let result = tokio::task::spawn_blocking(move || {
        mana_verify::run_verify_command(&verify_cmd, &working_dir, timeout_secs)
    })
    .await
    .map_err(|e| -> Box<dyn std::error::Error> { Box::new(e) })?
    .map_err(|e| -> Box<dyn std::error::Error> {
        Box::new(std::io::Error::other(e.to_string()))
    })?;

    let output = if result.passed {
        None
    } else if result.timed_out {
        Some(match result.timeout_secs {
            Some(secs) => format!("Verify timed out after {secs}s"),
            None => "Verify timed out".to_string(),
        })
    } else {
        let stderr = result.stderr.trim();
        let stdout = result.stdout.trim();
        if !stderr.is_empty() {
            Some(stderr.to_string())
        } else if !stdout.is_empty() {
            Some(stdout.to_string())
        } else {
            None
        }
    };

    Ok((result.passed, output))
}

/// Build a task prompt string from a worker assignment.
///
/// This is the user-facing prompt that starts the agent's work.
pub fn build_task_prompt(assignment: &WorkerAssignment) -> String {
    let mut prompt = format!("Task: {}", assignment.title);

    if !assignment.description.trim().is_empty() {
        prompt.push_str("\n\n");
        prompt.push_str(assignment.description.trim());
    }

    if let Some(notes) = assignment
        .notes
        .as_deref()
        .map(str::trim)
        .filter(|n| !n.is_empty())
    {
        prompt.push_str("\n\nNotes:\n");
        prompt.push_str(notes);
    }

    if !assignment.files.is_empty() || !assignment.paths.is_empty() {
        prompt.push_str("\n\nReferenced files:\n");
        for path in assignment.paths.iter().chain(assignment.files.iter()) {
            prompt.push_str("- ");
            prompt.push_str(path);
            prompt.push('\n');
        }
        while prompt.ends_with('\n') {
            prompt.pop();
        }
    }

    if !assignment.attempts.is_empty() {
        prompt.push_str("\n\nPrevious attempts:\n");
        for attempt in &assignment.attempts {
            prompt.push_str(&format!(
                "- Attempt {} ({}): {}\n",
                attempt.number, attempt.outcome, attempt.summary
            ));
        }
        while prompt.ends_with('\n') {
            prompt.pop();
        }
    }

    if let Some(verify) = assignment
        .verify
        .as_deref()
        .map(str::trim)
        .filter(|v| !v.is_empty())
    {
        prompt.push_str("\n\nVerify command: ");
        prompt.push_str(verify);
    }

    prompt
}

/// Assemble context prefill messages from the assignment's file references.
pub fn assemble_prefill(assignment: &WorkerAssignment, cwd: &Path) -> AssembledContext {
    let file_specs = if !assignment.files.is_empty() {
        assignment
            .files
            .iter()
            .filter_map(|s| parse_file_spec(s))
            .collect()
    } else if !assignment.paths.is_empty() {
        assignment
            .paths
            .iter()
            .filter_map(|s| parse_file_spec(s))
            .collect()
    } else {
        context_prefill::detect_file_paths(&assignment.description)
    };

    if file_specs.is_empty() {
        return AssembledContext::empty();
    }

    let config = PrefillConfig::default();
    context_prefill::assemble_context(&file_specs, cwd, &config)
}

// ---------------------------------------------------------------------------
// Helpers
// ---------------------------------------------------------------------------

/// Parse a file spec string like "src/foo.rs" or "src/foo.rs:tail:50".
fn parse_file_spec(s: &str) -> Option<FileSpec> {
    let s = s.trim();
    if s.is_empty() {
        return None;
    }

    let (path_str, suffix) = if let Some(dot_pos) = s.rfind('.') {
        let after_ext = &s[dot_pos..];
        if let Some(colon_pos) = after_ext.find(':') {
            let split_at = dot_pos + colon_pos;
            (&s[..split_at], Some(&s[split_at + 1..]))
        } else {
            (s, None)
        }
    } else {
        (s, None)
    };

    let mode = match suffix {
        Some(suf) if suf.starts_with("tail:") => suf[5..]
            .parse::<usize>()
            .ok()
            .map(context_prefill::FileMode::Tail)
            .unwrap_or(context_prefill::FileMode::Full),
        Some(suf) if suf.contains('-') => {
            let parts: Vec<&str> = suf.splitn(2, '-').collect();
            match (
                parts[0].parse::<usize>(),
                parts.get(1).and_then(|p| p.parse::<usize>().ok()),
            ) {
                (Ok(start), Some(end)) => context_prefill::FileMode::Range(start, end),
                _ => context_prefill::FileMode::Full,
            }
        }
        _ => context_prefill::FileMode::Full,
    };

    Some(FileSpec {
        path: PathBuf::from(path_str),
        mode,
    })
}

/// Extract the markdown body after YAML frontmatter.
fn extract_markdown_body(content: &str) -> Option<String> {
    let lines: Vec<&str> = content.lines().collect();
    if lines.first().copied() != Some("---") {
        return None;
    }
    let end = lines
        .iter()
        .enumerate()
        .skip(1)
        .find_map(|(i, line)| (*line == "---").then_some(i))?;
    let body = lines[end + 1..].join("\n");
    Some(body)
}

// ---------------------------------------------------------------------------
// Tests
// ---------------------------------------------------------------------------

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn build_task_prompt_basic() {
        let assignment = WorkerAssignment {
            id: "1".to_string(),
            title: "Fix the bug".to_string(),
            description: "There is a null pointer in foo.rs".to_string(),
            acceptance: None,
            verify: Some("cargo test".to_string()),
            notes: None,
            decisions: Vec::new(),
            dependencies: Vec::new(),
            paths: Vec::new(),
            files: Vec::new(),
            attempts: Vec::new(),
            workspace_root: PathBuf::from("/tmp"),
            model: None,
        };
        let prompt = build_task_prompt(&assignment);
        assert!(prompt.contains("Task: Fix the bug"));
        assert!(prompt.contains("null pointer"));
        assert!(prompt.contains("Verify command: cargo test"));
    }

    #[test]
    fn build_task_prompt_with_attempts() {
        let assignment = WorkerAssignment {
            id: "2".to_string(),
            title: "Add test".to_string(),
            description: "Add a test for auth".to_string(),
            acceptance: None,
            verify: None,
            notes: Some("Check the fixtures module".to_string()),
            decisions: Vec::new(),
            dependencies: Vec::new(),
            paths: vec!["tests/auth.rs".to_string()],
            files: vec!["src/fixtures.rs".to_string()],
            attempts: vec![WorkerAttempt {
                number: 1,
                outcome: "fail".to_string(),
                summary: "Wrong fixture path".to_string(),
            }],
            workspace_root: PathBuf::from("/tmp"),
            model: None,
        };
        let prompt = build_task_prompt(&assignment);
        assert!(prompt.contains("Notes:"));
        assert!(prompt.contains("Check the fixtures module"));
        assert!(prompt.contains("Previous attempts:"));
        assert!(prompt.contains("Referenced files:"));
        assert!(prompt.contains("tests/auth.rs"));
        assert!(prompt.contains("src/fixtures.rs"));
        assert!(prompt.contains("Attempt 1 (fail): Wrong fixture path"));
    }

    #[test]
    fn build_task_context_populates_fields() {
        let assignment = WorkerAssignment {
            id: "3".to_string(),
            title: "Refactor module".to_string(),
            description: "Split into submodules".to_string(),
            acceptance: Some("All tests pass".to_string()),
            verify: Some("cargo test".to_string()),
            notes: Some("Prefer touching parser and module wiring first".to_string()),
            decisions: vec!["Use mod.rs or inline?".to_string()],
            dependencies: Vec::new(),
            paths: vec!["src/lib.rs".to_string()],
            files: vec!["src/parser.rs".to_string()],
            attempts: Vec::new(),
            workspace_root: PathBuf::from("/tmp"),
            model: None,
        };
        let ctx = build_task_context(&assignment);
        assert_eq!(ctx.title, "Refactor module");
        assert_eq!(ctx.acceptance.as_deref(), Some("All tests pass"));
        assert_eq!(ctx.verify.as_deref(), Some("cargo test"));
        assert_eq!(
            ctx.notes.as_deref(),
            Some("Prefer touching parser and module wiring first")
        );
        assert_eq!(ctx.decisions, vec!["Use mod.rs or inline?"]);
        assert_eq!(ctx.context_paths, vec!["src/lib.rs", "src/parser.rs"]);
        assert!(ctx.constraints.iter().any(|c| c.contains("Scope changes")));
        assert!(ctx.constraints.iter().any(|c| c.contains("verify command")));
    }

    #[test]
    fn parse_file_spec_plain() {
        let spec = parse_file_spec("src/main.rs").unwrap();
        assert_eq!(spec.path, PathBuf::from("src/main.rs"));
        assert_eq!(spec.mode, context_prefill::FileMode::Full);
    }

    #[test]
    fn parse_file_spec_tail() {
        let spec = parse_file_spec("src/main.rs:tail:50").unwrap();
        assert_eq!(spec.path, PathBuf::from("src/main.rs"));
        assert_eq!(spec.mode, context_prefill::FileMode::Tail(50));
    }

    #[test]
    fn parse_file_spec_range() {
        let spec = parse_file_spec("src/main.rs:10-20").unwrap();
        assert_eq!(spec.path, PathBuf::from("src/main.rs"));
        assert_eq!(spec.mode, context_prefill::FileMode::Range(10, 20));
    }

    #[test]
    fn parse_file_spec_empty() {
        assert!(parse_file_spec("").is_none());
        assert!(parse_file_spec("  ").is_none());
    }

    #[test]
    fn extract_markdown_body_works() {
        let content = "---\ntitle: Test\n---\n\nBody text here.";
        let body = extract_markdown_body(content).unwrap();
        assert!(body.contains("Body text here."));
    }

    #[tokio::test]
    async fn run_verify_command_captures_stderr_without_printing() {
        let dir = tempfile::tempdir().unwrap();
        let (passed, output) =
            run_verify_command("missing", "printf 'boom' >&2; exit 1", dir.path())
                .await
                .unwrap();
        assert!(!passed);
        assert_eq!(output.as_deref(), Some("boom"));
    }

    #[tokio::test]
    async fn run_verify_command_reports_timeout_message() {
        let dir = tempfile::tempdir().unwrap();
        let mana_dir = dir.path().join(".mana");
        std::fs::create_dir_all(&mana_dir).unwrap();
        let unit = mana_core::unit::Unit {
            verify_timeout: Some(1),
            verify: Some("python3 -c 'import time; time.sleep(2)'".to_string()),
            ..mana_core::unit::Unit::new("11", "Slow verify")
        };
        unit.to_file(mana_dir.join("11-slow-verify.md")).unwrap();
        let (passed, output) =
            run_verify_command("11", "python3 -c 'import time; time.sleep(2)'", dir.path())
                .await
                .unwrap();
        assert!(!passed);
        assert_eq!(output.as_deref(), Some("Verify timed out after 1s"));
    }

    #[tokio::test]
    async fn run_verify_command_falls_back_to_stdout_when_stderr_is_empty() {
        let dir = tempfile::tempdir().unwrap();
        let (passed, output) = run_verify_command("missing", "printf 'nope'; exit 1", dir.path())
            .await
            .unwrap();
        assert!(!passed);
        assert_eq!(output.as_deref(), Some("nope"));
    }

    #[test]
    fn map_close_outcome_closed_is_completed() {
        let outcome = CloseOutcome::Closed(mana_core::ops::close::CloseResult {
            unit: mana_core::unit::Unit::new("1", "Task"),
            archive_path: PathBuf::from("/tmp/archive"),
            auto_closed_parents: Vec::new(),
            on_close_results: Vec::new(),
            warnings: Vec::new(),
            auto_commit_result: None,
            evidence: None,
        });

        let mapped = map_close_outcome("1", outcome);
        assert_eq!(mapped.status, WorkerStatus::Completed);
        assert!(mapped.closed_after_verify);
        assert!(mapped.error.is_none());
    }

    #[test]
    fn map_close_outcome_deferred_verify_is_awaiting_verify() {
        let mapped = map_close_outcome(
            "42",
            CloseOutcome::DeferredVerify {
                unit_id: "42".to_string(),
            },
        );
        assert_eq!(mapped.status, WorkerStatus::AwaitingVerify);
        assert!(!mapped.closed_after_verify);
    }

    #[test]
    fn map_close_outcome_feature_requires_human_is_blocked() {
        let mapped = map_close_outcome(
            "7",
            CloseOutcome::FeatureRequiresHuman {
                unit_id: "7".to_string(),
                title: "Feature work".to_string(),
                warnings: Vec::new(),
            },
        );
        assert_eq!(mapped.status, WorkerStatus::Blocked);
        assert!(mapped
            .summary
            .contains("requires human review to close feature"));
        assert!(mapped.error.is_some());
    }

    #[test]
    fn map_close_outcome_verify_failed_is_failed() {
        let mut unit = mana_core::unit::Unit::new("9", "Verify fail");
        unit.verify = Some("cargo test".to_string());
        let mapped = map_close_outcome(
            "9",
            CloseOutcome::VerifyFailed(VerifyFailureResult {
                unit,
                attempt_number: 1,
                exit_code: Some(1),
                output: "boom".to_string(),
                timed_out: false,
                on_fail_action_taken: None,
                verify_command: "cargo test".to_string(),
                timeout_secs: None,
                warnings: Vec::new(),
            }),
        );
        assert_eq!(mapped.status, WorkerStatus::Failed);
        assert_eq!(mapped.verify_output.as_deref(), Some("boom"));
        let verifier = mapped.verifier_result.expect("verifier result");
        assert_eq!(verifier.status, VerifierStatus::Failed);
        assert_eq!(verifier.command.as_deref(), Some("cargo test"));
        assert_eq!(verifier.unit_id.as_deref(), Some("9"));
        assert_eq!(verifier.artifact_refs.len(), 1);
        assert_eq!(verifier.artifact_refs[0].kind, ArtifactKind::VerifyOutput);
        assert!(mapped.error.unwrap().contains("cargo test"));
    }

    #[test]
    fn build_verify_failure_verifier_result_omits_artifact_when_output_empty() {
        let verifier = build_verify_failure_verifier_result(
            "11",
            &VerifyFailureResult {
                unit: mana_core::unit::Unit::new("11", "Verify fail"),
                attempt_number: 1,
                exit_code: Some(124),
                output: String::new(),
                timed_out: true,
                on_fail_action_taken: None,
                verify_command: "cargo test slow".to_string(),
                timeout_secs: Some(30),
                warnings: Vec::new(),
            },
        );
        assert_eq!(verifier.status, VerifierStatus::Failed);
        assert_eq!(verifier.summary.as_deref(), Some("verify timed out"));
        assert!(verifier.artifact_refs.is_empty());
    }

    #[test]
    fn extract_markdown_body_no_frontmatter() {
        assert!(extract_markdown_body("No frontmatter").is_none());
    }
}