//! Story metadata — parses and modifies YAML front matter in story markdown files.
use serde::Deserialize;
use std::fs;
use std::path::Path;

/// QA mode for a story: determines how the pipeline handles post-coder review.
///
/// - `Server` — skip the QA agent; rely on server gate checks (clippy + tests).
///   If gates pass, advance straight to merge.
/// - `Agent` — spin up a QA agent (Claude session) to review code and run gates.
/// - `Human` — hold in QA for human approval after server gates pass.
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum QaMode {
    Server,
    Agent,
    Human,
}

impl QaMode {
    /// Parse a string into a `QaMode`. Returns `None` for unrecognised values.
    pub fn from_str(s: &str) -> Option<Self> {
        match s.trim().to_lowercase().as_str() {
            "server" => Some(Self::Server),
            "agent" => Some(Self::Agent),
            "human" => Some(Self::Human),
            _ => None,
        }
    }

    pub fn as_str(&self) -> &'static str {
        match self {
            Self::Server => "server",
            Self::Agent => "agent",
            Self::Human => "human",
        }
    }
}

impl std::fmt::Display for QaMode {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        f.write_str(self.as_str())
    }
}

#[derive(Debug, Clone, PartialEq, Eq, Default)]
pub struct StoryMetadata {
    pub name: Option<String>,
    pub coverage_baseline: Option<String>,
    pub merge_failure: Option<String>,
    pub agent: Option<String>,
    pub review_hold: Option<bool>,
    pub qa: Option<QaMode>,
    /// Number of times this story has been retried at its current pipeline stage.
    pub retry_count: Option<u32>,
    /// When `true`, auto-assign will skip this story (retry limit exceeded).
    pub blocked: Option<bool>,
    /// Story numbers this story depends on. Auto-assign will skip this story
    /// until all dependencies have reached `5_done` or `6_archived`.
    pub depends_on: Option<Vec<u32>>,
}

#[derive(Debug, Clone, PartialEq, Eq)]
pub enum StoryMetaError {
    MissingFrontMatter,
    InvalidFrontMatter(String),
}

impl std::fmt::Display for StoryMetaError {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        match self {
            StoryMetaError::MissingFrontMatter => write!(f, "Missing front matter"),
            StoryMetaError::InvalidFrontMatter(msg) => write!(f, "Invalid front matter: {msg}"),
        }
    }
}

#[derive(Debug, Deserialize)]
struct FrontMatter {
    name: Option<String>,
    coverage_baseline: Option<String>,
    merge_failure: Option<String>,
    agent: Option<String>,
    review_hold: Option<bool>,
    /// Configurable QA mode field: "human", "server", or "agent".
    qa: Option<String>,
    /// Number of times this story has been retried at its current pipeline stage.
    retry_count: Option<u32>,
    /// When `true`, auto-assign will skip this story (retry limit exceeded).
    blocked: Option<bool>,
    /// Story numbers this story depends on.
    depends_on: Option<Vec<u32>>,
}

pub fn parse_front_matter(contents: &str) -> Result<StoryMetadata, StoryMetaError> {
    let mut lines = contents.lines();

    let first = lines.next().unwrap_or_default().trim();
    if first != "---" {
        return Err(StoryMetaError::MissingFrontMatter);
    }

    let mut front_lines = Vec::new();
    for line in &mut lines {
        let trimmed = line.trim();
        if trimmed == "---" {
            let raw = front_lines.join("\n");
            let front: FrontMatter = serde_yaml::from_str(&raw)
                .map_err(|e| StoryMetaError::InvalidFrontMatter(e.to_string()))?;
            return Ok(build_metadata(front));
        }
        front_lines.push(line);
    }

    Err(StoryMetaError::InvalidFrontMatter(
        "Missing closing front matter delimiter".to_string(),
    ))
}

fn build_metadata(front: FrontMatter) -> StoryMetadata {
    let qa = front.qa.as_deref().and_then(QaMode::from_str);

    StoryMetadata {
        name: front.name,
        coverage_baseline: front.coverage_baseline,
        merge_failure: front.merge_failure,
        agent: front.agent,
        review_hold: front.review_hold,
        qa,
        retry_count: front.retry_count,
        blocked: front.blocked,
        depends_on: front.depends_on,
    }
}

/// Write or update a `merge_failure:` field in the YAML front matter of a story file.
///
/// The reason is stored as a quoted YAML string so that colons, hashes, and newlines
/// in the failure message do not break front-matter parsing.
/// If no front matter is present, this is a no-op (returns Ok).
pub fn write_merge_failure(path: &Path, reason: &str) -> Result<(), String> {
    let contents =
        fs::read_to_string(path).map_err(|e| format!("Failed to read story file: {e}"))?;

    // Produce a YAML-safe inline quoted string: collapse newlines, escape inner quotes.
    let escaped = reason
        .replace('"', "\\\"")
        .replace('\n', " ")
        .replace('\r', "");
    let yaml_value = format!("\"{escaped}\"");

    let updated = set_front_matter_field(&contents, "merge_failure", &yaml_value);
    fs::write(path, &updated).map_err(|e| format!("Failed to write story file: {e}"))?;
    Ok(())
}

/// Write `review_hold: true` to the YAML front matter of a story file.
///
/// Used to mark spikes that have passed QA and are waiting for human review.
pub fn write_review_hold(path: &Path) -> Result<(), String> {
    let contents =
        fs::read_to_string(path).map_err(|e| format!("Failed to read story file: {e}"))?;
    let updated = set_front_matter_field(&contents, "review_hold", "true");
    fs::write(path, &updated).map_err(|e| format!("Failed to write story file: {e}"))?;
    Ok(())
}

/// Remove a key from the YAML front matter of a story file on disk.
///
/// If front matter is present and contains the key, the line is removed.
/// If no front matter or key is not found, the file is left unchanged.
pub fn clear_front_matter_field(path: &Path, key: &str) -> Result<(), String> {
    let contents =
        fs::read_to_string(path).map_err(|e| format!("Failed to read story file: {e}"))?;
    let updated = remove_front_matter_field(&contents, key);
    if updated != contents {
        fs::write(path, &updated).map_err(|e| format!("Failed to write story file: {e}"))?;
    }
    Ok(())
}

/// Remove a key: value line from the YAML front matter of a markdown string.
///
/// If no front matter (opening `---`) is found or the key is absent, returns content unchanged.
fn remove_front_matter_field(contents: &str, key: &str) -> String {
    let mut lines: Vec<String> = contents.lines().map(String::from).collect();
    if lines.is_empty() || lines[0].trim() != "---" {
        return contents.to_string();
    }

    let close_idx = match lines[1..].iter().position(|l| l.trim() == "---") {
        Some(i) => i + 1,
        None => return contents.to_string(),
    };

    let key_prefix = format!("{key}:");
    if let Some(idx) = lines[1..close_idx]
        .iter()
        .position(|l| l.trim_start().starts_with(&key_prefix))
        .map(|i| i + 1)
    {
        lines.remove(idx);
    } else {
        return contents.to_string();
    }

    let mut result = lines.join("\n");
    if contents.ends_with('\n') {
        result.push('\n');
    }
    result
}

/// Insert or update a key: value pair in the YAML front matter of a markdown string.
///
/// If no front matter (opening `---`) is found, returns the content unchanged.
pub fn set_front_matter_field(contents: &str, key: &str, value: &str) -> String {
    let mut lines: Vec<String> = contents.lines().map(String::from).collect();
    if lines.is_empty() || lines[0].trim() != "---" {
        return contents.to_string();
    }

    // Find closing --- (search from index 1)
    let close_idx = match lines[1..].iter().position(|l| l.trim() == "---") {
        Some(i) => i + 1,
        None => return contents.to_string(),
    };

    let key_prefix = format!("{key}:");
    let existing_idx = lines[1..close_idx]
        .iter()
        .position(|l| l.trim_start().starts_with(&key_prefix))
        .map(|i| i + 1);

    let new_line = format!("{key}: {value}");
    if let Some(idx) = existing_idx {
        lines[idx] = new_line;
    } else {
        lines.insert(close_idx, new_line);
    }

    let mut result = lines.join("\n");
    if contents.ends_with('\n') {
        result.push('\n');
    }
    result
}

/// Write `blocked: true` to the YAML front matter of a story file.
///
/// Used to mark stories that have exceeded the retry limit and should not
/// be auto-assigned again.
pub fn write_blocked(path: &Path) -> Result<(), String> {
    let contents =
        fs::read_to_string(path).map_err(|e| format!("Failed to read story file: {e}"))?;
    let updated = set_front_matter_field(&contents, "blocked", "true");
    fs::write(path, &updated).map_err(|e| format!("Failed to write story file: {e}"))?;
    Ok(())
}

/// Write or update a `depends_on:` field in the YAML front matter of a story file.
///
/// Serialises `deps` as an inline YAML sequence, e.g. `[477, 478]`.
/// If `deps` is empty the field is removed.
/// If no front matter is present, this is a no-op (returns Ok).
pub fn write_depends_on(path: &Path, deps: &[u32]) -> Result<(), String> {
    let contents =
        fs::read_to_string(path).map_err(|e| format!("Failed to read story file: {e}"))?;
    let updated = if deps.is_empty() {
        remove_front_matter_field(&contents, "depends_on")
    } else {
        let nums: Vec<String> = deps.iter().map(|n| n.to_string()).collect();
        let yaml_value = format!("[{}]", nums.join(", "));
        set_front_matter_field(&contents, "depends_on", &yaml_value)
    };
    fs::write(path, &updated).map_err(|e| format!("Failed to write story file: {e}"))?;
    Ok(())
}

/// Return the list of dependency story numbers from `story_id`'s front matter
/// that have **not** yet reached `5_done` or `6_archived`.
///
/// Returns an empty `Vec` when there are no unmet dependencies (including when
/// the story has no `depends_on` field at all).
pub fn check_unmet_deps(project_root: &Path, stage_dir: &str, story_id: &str) -> Vec<u32> {
    let path = project_root
        .join(".huskies")
        .join("work")
        .join(stage_dir)
        .join(format!("{story_id}.md"));
    let contents = match fs::read_to_string(&path) {
        Ok(c) => c,
        Err(_) => return Vec::new(),
    };
    let deps = match parse_front_matter(&contents)
        .ok()
        .and_then(|m| m.depends_on)
    {
        Some(d) => d,
        None => return Vec::new(),
    };
    deps.into_iter()
        .filter(|&dep| !dep_is_done(project_root, dep))
        .collect()
}

/// Return `true` if a story with the given numeric ID exists in `5_done` or `6_archived`.
///
/// **Dependency semantics:** Both `5_done` and `6_archived` satisfy a `depends_on` entry.
/// Stories auto-sweep from `5_done` to `6_archived` after 4 hours, so by the time a dep
/// reaches `6_archived`, the dependent story has already been promoted.  When a dep is
/// already in `6_archived` at the moment of promotion (e.g., it was manually archived or
/// abandoned before the dependent story was created), the dependency is still considered
/// satisfied — but a warning is logged so the user can see that the dep was archived, not
/// cleanly completed.  Use `check_archived_deps` to detect this case.
fn dep_is_done(project_root: &Path, dep_number: u32) -> bool {
    let prefix = format!("{dep_number}_");
    let exact = dep_number.to_string();
    for stage in &["5_done", "6_archived"] {
        let dir = project_root.join(".huskies").join("work").join(stage);
        if let Ok(entries) = fs::read_dir(&dir) {
            for entry in entries.flatten() {
                let path = entry.path();
                if path.extension().and_then(|e| e.to_str()) != Some("md") {
                    continue;
                }
                if let Some(stem) = path.file_stem().and_then(|s| s.to_str())
                    && (stem == exact || stem.starts_with(&prefix))
                {
                    return true;
                }
            }
        }
    }
    false
}

/// Return `true` if a story with the given numeric ID exists specifically in `6_archived`
/// (i.e., it satisfies a `depends_on` but via the archive rather than via a clean done).
fn dep_is_archived(project_root: &Path, dep_number: u32) -> bool {
    let prefix = format!("{dep_number}_");
    let exact = dep_number.to_string();
    let dir = project_root
        .join(".huskies")
        .join("work")
        .join("6_archived");
    if let Ok(entries) = fs::read_dir(&dir) {
        for entry in entries.flatten() {
            let path = entry.path();
            if path.extension().and_then(|e| e.to_str()) != Some("md") {
                continue;
            }
            if let Some(stem) = path.file_stem().and_then(|s| s.to_str())
                && (stem == exact || stem.starts_with(&prefix))
            {
                return true;
            }
        }
    }
    false
}

/// Return the list of dependency story numbers from `story_id`'s front matter
/// that are in `6_archived` (satisfied via archive rather than via normal done).
///
/// Used to emit a warning when backlog promotion fires because a dep was archived
/// rather than cleanly completed.  Returns an empty `Vec` when no deps are archived.
pub fn check_archived_deps(project_root: &Path, stage_dir: &str, story_id: &str) -> Vec<u32> {
    let path = project_root
        .join(".huskies")
        .join("work")
        .join(stage_dir)
        .join(format!("{story_id}.md"));
    let contents = match fs::read_to_string(&path) {
        Ok(c) => c,
        Err(_) => return Vec::new(),
    };
    let deps = match parse_front_matter(&contents)
        .ok()
        .and_then(|m| m.depends_on)
    {
        Some(d) => d,
        None => return Vec::new(),
    };
    deps.into_iter()
        .filter(|&dep| dep_is_archived(project_root, dep))
        .collect()
}

/// Given an explicit list of dep numbers, return those already in `6_archived`.
///
/// Used at story-creation time when the dep list is known in memory (before the
/// story file has been written), so the caller does not need to parse the story.
pub fn check_archived_deps_from_list(project_root: &Path, deps: &[u32]) -> Vec<u32> {
    deps.iter()
        .copied()
        .filter(|&dep| dep_is_archived(project_root, dep))
        .collect()
}

// ── In-memory content variants (no filesystem access) ───────────────

/// Remove a key from the YAML front matter of a markdown string (pure function).
///
/// Returns the updated content.  If no front matter or key is not found,
/// returns the original content unchanged.
pub fn clear_front_matter_field_in_content(contents: &str, key: &str) -> String {
    remove_front_matter_field(contents, key)
}

/// Append rejection notes to a markdown string (pure function).
///
/// Returns the updated content with a `## QA Rejection Notes` section appended.
pub fn write_rejection_notes_to_content(contents: &str, notes: &str) -> String {
    let section = format!("\n\n## QA Rejection Notes\n\n{notes}\n");
    format!("{contents}{section}")
}

/// Resolve the effective QA mode from story content (no filesystem access).
///
/// Parses front matter from `contents` and returns the `qa` field if present,
/// otherwise returns `default`.
pub fn resolve_qa_mode_from_content(contents: &str, default: QaMode) -> QaMode {
    match parse_front_matter(contents) {
        Ok(meta) => meta.qa.unwrap_or(default),
        Err(_) => default,
    }
}

/// Increment the `retry_count` field in story content (pure function).
///
/// Returns `(updated_content, new_count)`.
pub fn increment_retry_count_in_content(contents: &str) -> (String, u32) {
    let current = parse_front_matter(contents)
        .ok()
        .and_then(|m| m.retry_count)
        .unwrap_or(0);
    let new_count = current + 1;
    let updated = set_front_matter_field(contents, "retry_count", &new_count.to_string());
    (updated, new_count)
}

/// Write `blocked: true` to story content (pure function).
pub fn write_blocked_in_content(contents: &str) -> String {
    set_front_matter_field(contents, "blocked", "true")
}

/// Write or update `merge_failure` in story content (pure function).
pub fn write_merge_failure_in_content(contents: &str, reason: &str) -> String {
    let escaped = reason
        .replace('"', "\\\"")
        .replace('\n', " ")
        .replace('\r', "");
    let yaml_value = format!("\"{escaped}\"");
    set_front_matter_field(contents, "merge_failure", &yaml_value)
}

/// Write `review_hold: true` to story content (pure function).
pub fn write_review_hold_in_content(contents: &str) -> String {
    set_front_matter_field(contents, "review_hold", "true")
}

/// Write or update `depends_on` in story content (pure function).
///
/// Serialises `deps` as an inline YAML sequence, e.g. `[477, 478]`.
/// If `deps` is empty the field is removed.
pub fn write_depends_on_in_content(contents: &str, deps: &[u32]) -> String {
    if deps.is_empty() {
        remove_front_matter_field(contents, "depends_on")
    } else {
        let nums: Vec<String> = deps.iter().map(|n| n.to_string()).collect();
        let yaml_value = format!("[{}]", nums.join(", "));
        set_front_matter_field(contents, "depends_on", &yaml_value)
    }
}

/// Resolve the effective QA mode for a story file.
///
/// Reads the `qa` front matter field. If absent, falls back to `default`.
/// Spikes are **not** handled here — the caller is responsible for overriding
/// to `Human` for spikes.
pub fn resolve_qa_mode(path: &Path, default: QaMode) -> QaMode {
    let contents = match fs::read_to_string(path) {
        Ok(c) => c,
        Err(_) => return default,
    };
    match parse_front_matter(&contents) {
        Ok(meta) => meta.qa.unwrap_or(default),
        Err(_) => default,
    }
}

pub fn parse_unchecked_todos(contents: &str) -> Vec<String> {
    contents
        .lines()
        .filter_map(|line| {
            let trimmed = line.trim();
            trimmed.strip_prefix("- [ ] ").map(|text| text.to_string())
        })
        .collect()
}

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

    #[test]
    fn parses_front_matter_metadata() {
        let input = r#"---
name: Establish the TDD Workflow and Gates
workflow: tdd
---
# Story 26
"#;

        let meta = parse_front_matter(input).expect("front matter");
        assert_eq!(
            meta.name.as_deref(),
            Some("Establish the TDD Workflow and Gates")
        );
        assert_eq!(meta.coverage_baseline, None);
    }

    #[test]
    fn parses_coverage_baseline_from_front_matter() {
        let input = "---\nname: Test Story\ncoverage_baseline: 78.5%\n---\n# Story\n";
        let meta = parse_front_matter(input).expect("front matter");
        assert_eq!(meta.coverage_baseline.as_deref(), Some("78.5%"));
    }

    #[test]
    fn set_front_matter_field_inserts_new_key() {
        let input = "---\nname: My Story\n---\n# Body\n";
        let output = set_front_matter_field(input, "coverage_baseline", "55.0%");
        assert!(output.contains("coverage_baseline: 55.0%"));
        assert!(output.contains("name: My Story"));
        assert!(output.ends_with('\n'));
    }

    #[test]
    fn set_front_matter_field_updates_existing_key() {
        let input = "---\nname: My Story\ncoverage_baseline: 40.0%\n---\n# Body\n";
        let output = set_front_matter_field(input, "coverage_baseline", "55.0%");
        assert!(output.contains("coverage_baseline: 55.0%"));
        assert!(!output.contains("40.0%"));
    }

    #[test]
    fn set_front_matter_field_no_op_without_front_matter() {
        let input = "# No front matter\n";
        let output = set_front_matter_field(input, "coverage_baseline", "55.0%");
        assert_eq!(output, input);
    }

    #[test]
    fn rejects_missing_front_matter() {
        let input = "# Story 26\n";
        assert_eq!(
            parse_front_matter(input),
            Err(StoryMetaError::MissingFrontMatter)
        );
    }

    #[test]
    fn rejects_unclosed_front_matter() {
        let input = "---\nname: Test\n";
        assert!(matches!(
            parse_front_matter(input),
            Err(StoryMetaError::InvalidFrontMatter(_))
        ));
    }

    #[test]
    fn remove_front_matter_field_removes_key() {
        let input = "---\nname: My Story\nmerge_failure: \"something broke\"\n---\n# Body\n";
        let output = remove_front_matter_field(input, "merge_failure");
        assert!(!output.contains("merge_failure"));
        assert!(output.contains("name: My Story"));
        assert!(output.ends_with('\n'));
    }

    #[test]
    fn remove_front_matter_field_no_op_when_absent() {
        let input = "---\nname: My Story\n---\n# Body\n";
        let output = remove_front_matter_field(input, "merge_failure");
        assert_eq!(output, input);
    }

    #[test]
    fn remove_front_matter_field_no_op_without_front_matter() {
        let input = "# No front matter\n";
        let output = remove_front_matter_field(input, "merge_failure");
        assert_eq!(output, input);
    }

    #[test]
    fn clear_front_matter_field_updates_file() {
        let tmp = tempfile::tempdir().unwrap();
        let path = tmp.path().join("story.md");
        std::fs::write(
            &path,
            "---\nname: Test\nmerge_failure: \"bad\"\n---\n# Story\n",
        )
        .unwrap();
        clear_front_matter_field(&path, "merge_failure").unwrap();
        let contents = std::fs::read_to_string(&path).unwrap();
        assert!(!contents.contains("merge_failure"));
        assert!(contents.contains("name: Test"));
    }

    #[test]
    fn parse_unchecked_todos_mixed() {
        let input = "## AC\n- [ ] First thing\n- [x] Done thing\n- [ ] Second thing\n";
        assert_eq!(
            parse_unchecked_todos(input),
            vec!["First thing", "Second thing"]
        );
    }

    #[test]
    fn parse_unchecked_todos_all_checked() {
        let input = "- [x] Done\n- [x] Also done\n";
        assert!(parse_unchecked_todos(input).is_empty());
    }

    #[test]
    fn parse_unchecked_todos_no_checkboxes() {
        let input = "# Story\nSome text\n- A bullet\n";
        assert!(parse_unchecked_todos(input).is_empty());
    }

    #[test]
    fn parse_unchecked_todos_leading_whitespace() {
        let input = "  - [ ] Indented item\n";
        assert_eq!(parse_unchecked_todos(input), vec!["Indented item"]);
    }

    #[test]
    fn parses_review_hold_from_front_matter() {
        let input = "---\nname: Spike\nreview_hold: true\n---\n# Spike\n";
        let meta = parse_front_matter(input).expect("front matter");
        assert_eq!(meta.review_hold, Some(true));
    }

    #[test]
    fn review_hold_defaults_to_none() {
        let input = "---\nname: Story\n---\n# Story\n";
        let meta = parse_front_matter(input).expect("front matter");
        assert_eq!(meta.review_hold, None);
    }

    #[test]
    fn write_review_hold_sets_field() {
        let tmp = tempfile::tempdir().unwrap();
        let path = tmp.path().join("spike.md");
        std::fs::write(&path, "---\nname: My Spike\n---\n# Spike\n").unwrap();
        write_review_hold(&path).unwrap();
        let contents = std::fs::read_to_string(&path).unwrap();
        assert!(contents.contains("review_hold: true"));
        assert!(contents.contains("name: My Spike"));
    }

    #[test]
    fn parses_qa_mode_from_front_matter() {
        let input = "---\nname: Story\nqa: server\n---\n# Story\n";
        let meta = parse_front_matter(input).expect("front matter");
        assert_eq!(meta.qa, Some(QaMode::Server));

        let input = "---\nname: Story\nqa: agent\n---\n# Story\n";
        let meta = parse_front_matter(input).expect("front matter");
        assert_eq!(meta.qa, Some(QaMode::Agent));

        let input = "---\nname: Story\nqa: human\n---\n# Story\n";
        let meta = parse_front_matter(input).expect("front matter");
        assert_eq!(meta.qa, Some(QaMode::Human));
    }

    #[test]
    fn qa_mode_defaults_to_none() {
        let input = "---\nname: Story\n---\n# Story\n";
        let meta = parse_front_matter(input).expect("front matter");
        assert_eq!(meta.qa, None);
    }

    #[test]
    fn resolve_qa_mode_uses_file_value() {
        let tmp = tempfile::tempdir().unwrap();
        let path = tmp.path().join("story.md");
        std::fs::write(&path, "---\nname: Test\nqa: human\n---\n# Story\n").unwrap();
        assert_eq!(resolve_qa_mode(&path, QaMode::Server), QaMode::Human);
    }

    #[test]
    fn resolve_qa_mode_falls_back_to_default() {
        let tmp = tempfile::tempdir().unwrap();
        let path = tmp.path().join("story.md");
        std::fs::write(&path, "---\nname: Test\n---\n# Story\n").unwrap();
        assert_eq!(resolve_qa_mode(&path, QaMode::Server), QaMode::Server);
        assert_eq!(resolve_qa_mode(&path, QaMode::Agent), QaMode::Agent);
    }

    #[test]
    fn resolve_qa_mode_missing_file_uses_default() {
        let path = std::path::Path::new("/nonexistent/story.md");
        assert_eq!(resolve_qa_mode(path, QaMode::Server), QaMode::Server);
    }

    #[test]
    fn parses_depends_on_from_front_matter() {
        let input = "---\nname: Story\ndepends_on: [477, 478]\n---\n# Story\n";
        let meta = parse_front_matter(input).expect("front matter");
        assert_eq!(meta.depends_on, Some(vec![477, 478]));
    }

    #[test]
    fn depends_on_defaults_to_none() {
        let input = "---\nname: Story\n---\n# Story\n";
        let meta = parse_front_matter(input).expect("front matter");
        assert_eq!(meta.depends_on, None);
    }

    #[test]
    fn write_depends_on_sets_field() {
        let tmp = tempfile::tempdir().unwrap();
        let path = tmp.path().join("story.md");
        std::fs::write(&path, "---\nname: Test\n---\n# Story\n").unwrap();
        write_depends_on(&path, &[477, 478]).unwrap();
        let contents = std::fs::read_to_string(&path).unwrap();
        assert!(contents.contains("depends_on: [477, 478]"), "{contents}");
    }

    #[test]
    fn write_depends_on_removes_field_when_empty() {
        let tmp = tempfile::tempdir().unwrap();
        let path = tmp.path().join("story.md");
        std::fs::write(&path, "---\nname: Test\ndepends_on: [477]\n---\n# Story\n").unwrap();
        write_depends_on(&path, &[]).unwrap();
        let contents = std::fs::read_to_string(&path).unwrap();
        assert!(!contents.contains("depends_on"), "{contents}");
    }

    #[test]
    fn check_unmet_deps_returns_empty_when_no_deps() {
        let tmp = tempfile::tempdir().unwrap();
        let stage = tmp.path().join(".huskies/work/2_current");
        std::fs::create_dir_all(&stage).unwrap();
        std::fs::write(stage.join("10_story_foo.md"), "---\nname: Foo\n---\n").unwrap();
        let unmet = check_unmet_deps(tmp.path(), "2_current", "10_story_foo");
        assert!(unmet.is_empty());
    }

    #[test]
    fn check_unmet_deps_returns_unmet_numbers() {
        let tmp = tempfile::tempdir().unwrap();
        let current = tmp.path().join(".huskies/work/2_current");
        let done = tmp.path().join(".huskies/work/5_done");
        std::fs::create_dir_all(&current).unwrap();
        std::fs::create_dir_all(&done).unwrap();
        // Dep 477 is done, dep 478 is not.
        std::fs::write(done.join("477_story_dep.md"), "---\nname: Dep\n---\n").unwrap();
        std::fs::write(
            current.join("10_story_foo.md"),
            "---\nname: Foo\ndepends_on: [477, 478]\n---\n",
        )
        .unwrap();
        let unmet = check_unmet_deps(tmp.path(), "2_current", "10_story_foo");
        assert_eq!(unmet, vec![478]);
    }

    #[test]
    fn check_unmet_deps_returns_empty_when_all_deps_done() {
        let tmp = tempfile::tempdir().unwrap();
        let current = tmp.path().join(".huskies/work/2_current");
        let done = tmp.path().join(".huskies/work/5_done");
        std::fs::create_dir_all(&current).unwrap();
        std::fs::create_dir_all(&done).unwrap();
        std::fs::write(done.join("477_story_a.md"), "---\nname: A\n---\n").unwrap();
        std::fs::write(done.join("478_story_b.md"), "---\nname: B\n---\n").unwrap();
        std::fs::write(
            current.join("10_story_foo.md"),
            "---\nname: Foo\ndepends_on: [477, 478]\n---\n",
        )
        .unwrap();
        let unmet = check_unmet_deps(tmp.path(), "2_current", "10_story_foo");
        assert!(unmet.is_empty());
    }

    #[test]
    fn dep_is_done_finds_story_in_archived() {
        let tmp = tempfile::tempdir().unwrap();
        let archived = tmp.path().join(".huskies/work/6_archived");
        std::fs::create_dir_all(&archived).unwrap();
        std::fs::write(archived.join("100_story_old.md"), "---\nname: Old\n---\n").unwrap();
        assert!(dep_is_done(tmp.path(), 100));
        assert!(!dep_is_done(tmp.path(), 101));
    }

    // ── Bug 503: archived-dep visibility ─────────────────────────────────────

    /// check_archived_deps returns the dep IDs that are in 6_archived.
    #[test]
    fn check_archived_deps_returns_archived_dep_numbers() {
        let tmp = tempfile::tempdir().unwrap();
        let current = tmp.path().join(".huskies/work/2_current");
        let archived = tmp.path().join(".huskies/work/6_archived");
        std::fs::create_dir_all(&current).unwrap();
        std::fs::create_dir_all(&archived).unwrap();
        // Dep 100 is in 6_archived; dep 101 is not anywhere.
        std::fs::write(archived.join("100_spike_old.md"), "---\nname: Old\n---\n").unwrap();
        std::fs::write(
            current.join("5_story_dependent.md"),
            "---\nname: Dep\ndepends_on: [100, 101]\n---\n",
        )
        .unwrap();
        let archived_deps = check_archived_deps(tmp.path(), "2_current", "5_story_dependent");
        assert_eq!(archived_deps, vec![100]);
    }

    /// check_archived_deps returns empty when no deps are in 6_archived.
    #[test]
    fn check_archived_deps_returns_empty_when_dep_in_done() {
        let tmp = tempfile::tempdir().unwrap();
        let backlog = tmp.path().join(".huskies/work/1_backlog");
        let done = tmp.path().join(".huskies/work/5_done");
        std::fs::create_dir_all(&backlog).unwrap();
        std::fs::create_dir_all(&done).unwrap();
        // Dep 200 is in 5_done (not archived).
        std::fs::write(done.join("200_story_done.md"), "---\nname: Done\n---\n").unwrap();
        std::fs::write(
            backlog.join("5_story_waiting.md"),
            "---\nname: Waiting\ndepends_on: [200]\n---\n",
        )
        .unwrap();
        let archived_deps = check_archived_deps(tmp.path(), "1_backlog", "5_story_waiting");
        assert!(archived_deps.is_empty());
    }

    /// check_archived_deps returns empty when story has no depends_on.
    #[test]
    fn check_archived_deps_returns_empty_when_no_deps() {
        let tmp = tempfile::tempdir().unwrap();
        let current = tmp.path().join(".huskies/work/2_current");
        std::fs::create_dir_all(&current).unwrap();
        std::fs::write(current.join("3_story_free.md"), "---\nname: Free\n---\n").unwrap();
        let archived_deps = check_archived_deps(tmp.path(), "2_current", "3_story_free");
        assert!(archived_deps.is_empty());
    }

    /// check_archived_deps_from_list returns archived dep IDs from an in-memory list.
    #[test]
    fn check_archived_deps_from_list_returns_archived_ids() {
        let tmp = tempfile::tempdir().unwrap();
        let done = tmp.path().join(".huskies/work/5_done");
        let archived = tmp.path().join(".huskies/work/6_archived");
        std::fs::create_dir_all(&done).unwrap();
        std::fs::create_dir_all(&archived).unwrap();
        std::fs::write(done.join("10_story_done.md"), "---\nname: Done\n---\n").unwrap();
        std::fs::write(archived.join("20_story_old.md"), "---\nname: Old\n---\n").unwrap();
        // Only 20 is archived; 10 is in done, 30 is nowhere.
        let result = check_archived_deps_from_list(tmp.path(), &[10, 20, 30]);
        assert_eq!(result, vec![20]);
    }

    /// check_archived_deps_from_list returns empty when no deps are archived.
    #[test]
    fn check_archived_deps_from_list_empty_when_no_archived_deps() {
        let tmp = tempfile::tempdir().unwrap();
        let done = tmp.path().join(".huskies/work/5_done");
        std::fs::create_dir_all(&done).unwrap();
        std::fs::write(done.join("10_story_done.md"), "---\nname: Done\n---\n").unwrap();
        let result = check_archived_deps_from_list(tmp.path(), &[10]);
        assert!(result.is_empty());
    }

    /// dep_is_archived returns true only for stories in 6_archived, not 5_done.
    #[test]
    fn dep_is_archived_distinguishes_done_from_archived() {
        let tmp = tempfile::tempdir().unwrap();
        let done = tmp.path().join(".huskies/work/5_done");
        let archived = tmp.path().join(".huskies/work/6_archived");
        std::fs::create_dir_all(&done).unwrap();
        std::fs::create_dir_all(&archived).unwrap();
        std::fs::write(done.join("10_story_done.md"), "---\nname: Done\n---\n").unwrap();
        std::fs::write(archived.join("20_story_old.md"), "---\nname: Old\n---\n").unwrap();
        // 10 is in 5_done only — not archived.
        assert!(!dep_is_archived(tmp.path(), 10));
        // 20 is in 6_archived — archived.
        assert!(dep_is_archived(tmp.path(), 20));
        // 99 doesn't exist anywhere.
        assert!(!dep_is_archived(tmp.path(), 99));
    }
}