tix-tracker 0.12.0

use std::io::IsTerminal;
use std::path::Path;
use std::process::Command;

use crate::config::Config;
use crate::error::{Result, TixError};
use crate::model::Issue;

/// Read a single line from TTY with basic readline-style editing.
///
/// This replaces `std::io::stdin().read_line` for interactive prompts so
/// common editing shortcuts (Ctrl-A/E, arrows, delete/backspace) work.
pub fn read_tty_line(prompt: &str) -> Result<String> {
    if !std::io::stdin().is_terminal() {
        return Err(TixError::InvalidInput(
            "interactive input requires a TTY; pass an explicit argument instead".into(),
        ));
    }

    use reedline::{DefaultPrompt, DefaultPromptSegment, Reedline, Signal};

    let mut line_editor = Reedline::create();
    let prompt = DefaultPrompt::new(
        DefaultPromptSegment::Basic(prompt.to_string()),
        DefaultPromptSegment::Empty,
    );

    match line_editor.read_line(&prompt) {
        Ok(Signal::Success(input)) => Ok(input.trim().to_string()),
        Ok(Signal::CtrlC) | Ok(Signal::CtrlD) => {
            Err(TixError::InvalidInput("input cancelled".into()))
        }
        Err(e) => Err(TixError::Editor(format!("failed to read tty line: {e}"))),
    }
}

pub struct FieldEdits {
    pub title: Option<String>,
    pub status: Option<String>,
    pub priority: Option<String>,
    pub labels: Option<Vec<String>>,
    pub files: Option<Vec<String>>,
    /// General cross-repository references, replacing the whole list when
    /// present (`Some(vec![])` clears). Free-form strings, stored verbatim.
    pub related_issues: Option<Vec<String>>,
    /// Issue type. `Some(None)` clears it, `Some(Some(v))` sets it; absent leaves
    /// it untouched.
    pub type_: Option<Option<String>>,
    pub assignee: Option<Option<String>>,
    pub estimate: Option<Option<String>>,
    pub commit: Option<Option<String>>,
    pub cycles: Option<Option<Vec<String>>>,
    pub milestones: Option<Option<Vec<String>>>,
    pub reviewer: Option<Option<String>>,
    pub start_date: Option<Option<String>>,
    pub due_date: Option<Option<String>>,
    /// The decomposition parent, as a **resolved canonical issue reference**.
    ///
    /// `Some(None)` clears it, mirroring `assignee` and every other optional field:
    /// an absent flag leaves it untouched, `--parent ""` removes it.
    ///
    /// A canonical id, never a selector, because a title is not stable and a stored title
    /// would silently break every child on a retitle. Resolution happens in
    /// [`crate::commands::edit`] against the store, which `merge_fields` has no
    /// access to.
    ///
    /// **Out of map for WP03** (`src/editor.rs` is in no WP's `owned_files`; see tix
    /// #1374). The field lives here, rather than as a separate parameter, because
    /// that is exactly what `assignee` does: the value is merged so the merge stays
    /// uniform, and the side effect `merge_fields` cannot perform — here validating
    /// through the hierarchy service and appending the History event — happens
    /// around it in the caller. The alternative, a second write path in `edit` that
    /// bypasses the merge, is what `assignee`'s precedent argues against.
    pub parent: Option<Option<crate::id::IssueRef>>,
}

pub fn resolve_editor(pref: Option<&str>) -> Result<String> {
    resolve_editor_with_env(
        pref,
        std::env::var("EDITOR").ok(),
        std::env::var("VISUAL").ok(),
    )
}

pub fn resolve_agent(pref: Option<&str>) -> Result<String> {
    resolve_editor_with_env(
        pref,
        std::env::var("TIX_AGENT")
            .ok()
            .or_else(|| std::env::var("AGENT").ok()),
        std::env::var("VISUAL").ok(),
    )
}

fn resolve_editor_with_env(
    pref: Option<&str>,
    editor: Option<String>,
    visual: Option<String>,
) -> Result<String> {
    if let Some(e) = pref
        && !e.is_empty()
    {
        return Ok(e.to_string());
    }
    if let Some(e) = editor.filter(|v| !v.is_empty()) {
        return Ok(e);
    }
    if let Some(e) = visual.filter(|v| !v.is_empty()) {
        return Ok(e);
    }
    let fallbacks: &[&str] = if cfg!(target_os = "windows") {
        &["cmd", "nano", "vi"]
    } else {
        &["editor", "nano", "vi"]
    };
    for name in fallbacks {
        if which(name) {
            return Ok(name.to_string());
        }
    }
    Err(TixError::Editor("no editor found".into()))
}

/// Run the editor on `path` and wait for it.
///
/// This runs the editor and nothing else (tix #1506). It deliberately does
/// **not** validate the result: the old trailing `Issue::parse` threw the real
/// diagnostic away and replaced it with `file not valid after edit`, so the
/// caller could not tell a duplicate key from a missing fence. Callers parse the
/// copy themselves and classify what came back with [`crate::edit_problems`],
/// which is where a problem's fix lives.
pub fn run_editor(editor: &str, path: &Path, _config: &Config) -> Result<()> {
    let status = Command::new(editor)
        .arg(path)
        .status()
        .map_err(|e| TixError::Editor(format!("failed to launch {editor}: {e}")))?;
    if !status.success() {
        return Err(TixError::Editor(format!(
            "editor {editor} exited with {status}"
        )));
    }
    Ok(())
}

/// The auto viewer probe chain, in the order tix tries the programs (tix #1507).
///
/// `mdterm` first because it is the tool built for this — a read-only markdown
/// pager. `batcat` is Debian's name for `bat`, and `most`/`less`/`more` are the
/// pagers nearly every system ships one of.
pub const VIEWER_CANDIDATES: &[&str] = &["mdterm", "batcat", "most", "less", "more"];

/// Resolve the read-only viewer used by the TUI's `v` key (tix #1507).
///
/// An explicit, non-`auto` preference wins. `None`, `Some("auto")`, and a
/// whitespace-only value are the probe chain; a whitespace-only value is an
/// error rather than a silent fallback, because the way to ask for the chain is
/// `auto` (or omitting the key).
///
/// The `auto` probe result is cached for the process, so a surface that renders
/// the resolved name does not spawn `which` on every frame.
pub fn resolve_viewer(pref: Option<&str>) -> Result<String> {
    static AUTO_VIEWER: std::sync::LazyLock<Option<String>> = std::sync::LazyLock::new(|| {
        VIEWER_CANDIDATES
            .iter()
            .find(|name| which(name))
            .map(|name| (*name).to_string())
    });
    resolve_viewer_with(pref, |name| AUTO_VIEWER.as_deref() == Some(name))
}

/// [`resolve_viewer`] with the PATH probe injected, so the ordering, the
/// override, and the none-found error are testable without the host's PATH.
pub fn resolve_viewer_with(pref: Option<&str>, probe: impl Fn(&str) -> bool) -> Result<String> {
    if let Some(name) = explicit_viewer(pref)? {
        return Ok(name);
    }
    VIEWER_CANDIDATES
        .iter()
        .find(|name| probe(name))
        .map(|name| (*name).to_string())
        .ok_or_else(no_viewer_error)
}

/// The trimmed explicit viewer, or `None` when the preference means "auto".
///
/// Errors on a whitespace-only preference: it is neither a usable program nor a
/// request for the chain, so guessing at the user's intent would be worse than
/// saying so.
fn explicit_viewer(pref: Option<&str>) -> Result<Option<String>> {
    match pref {
        None => Ok(None),
        Some(raw) => {
            let name = raw.trim();
            if name.is_empty() {
                return Err(TixError::Editor(
                    "`viewer` must not be blank; use `auto` for the default chain".into(),
                ));
            }
            if name == "auto" {
                Ok(None)
            } else {
                Ok(Some(name.to_string()))
            }
        }
    }
}

fn no_viewer_error() -> TixError {
    TixError::Editor(format!(
        "no viewer found: install one of {} (or set `viewer` in tix.toml)",
        VIEWER_CANDIDATES.join(", ")
    ))
}

/// Run a read-only viewer on `path`, with inherited stdio and a wait.
///
/// Mirrors [`run_editor`]'s mechanics — same inherited terminal, same wait — but
/// strictly read-only: no temp file, no read-back, no write. A **non-zero exit
/// is not an error**: a pager exits non-zero on an ordinary quit, so reporting
/// that would turn every close into a failure message. Only a spawn failure is
/// an error.
pub fn run_viewer(viewer: &str, path: &Path) -> Result<()> {
    Command::new(viewer)
        .arg(path)
        .status()
        .map_err(|e| TixError::Editor(format!("failed to launch {viewer}: {e}")))?;
    Ok(())
}

pub fn merge_fields(issue: &Issue, edits: &FieldEdits) -> Issue {
    let mut result = issue.clone();
    if let Some(ref title) = edits.title {
        result.title = title.clone();
    }
    if let Some(ref status) = edits.status {
        result.status = crate::model::Status::new(status);
    }
    if let Some(ref priority) = edits.priority {
        result.priority = priority.parse().unwrap_or_default();
    }
    if let Some(ref labels) = edits.labels {
        result.labels = labels.clone();
    }
    if let Some(ref files) = edits.files {
        result.files = files.clone();
    }
    if let Some(related_issues) = &edits.related_issues {
        result.related_issues = related_issues.clone();
    }
    if let Some(t) = &edits.type_ {
        result.type_ = t.clone();
    }
    if let Some(ref assignee) = edits.assignee {
        result.assignee = assignee.clone();
    }
    if let Some(ref estimate) = edits.estimate {
        result.estimate = estimate.clone();
    }
    if let Some(ref commit) = edits.commit {
        result.commit = commit.clone();
    }
    if let Some(ref cycles) = edits.cycles {
        result.cycles = cycles.clone();
    }
    if let Some(ref milestones) = edits.milestones {
        result.milestones = milestones.clone();
    }
    if let Some(ref reviewer) = edits.reviewer {
        result.reviewer = reviewer.clone();
    }
    if let Some(ref start_date) = edits.start_date {
        result.start_date = start_date.clone();
    }
    if let Some(ref due_date) = edits.due_date {
        result.due_date = due_date.clone();
    }
    if let Some(ref parent) = edits.parent {
        result.parent = *parent;
    }
    result
}

fn which(name: &str) -> bool {
    let output = Command::new("which")
        .arg(name)
        .output()
        .map(|o| o.status.success());
    output.unwrap_or(false)
}

#[cfg(test)]
mod tests {
    #[allow(clippy::wildcard_imports)]
    use super::*;
    use crate::model::{Priority, Status};
    use std::fs;
    use tempfile::TempDir;

    #[test]
    fn resolve_editor_pref_wins() {
        let result = resolve_editor_with_env(Some("nvim"), None, None).unwrap();
        assert_eq!(result, "nvim");
    }

    #[test]
    fn resolve_editor_pref_empty_falls_through() {
        let result = resolve_editor_with_env(Some(""), Some("vim".into()), None).unwrap();
        assert_eq!(result, "vim");
    }

    #[test]
    fn resolve_editor_editor_env() {
        let result = resolve_editor_with_env(None, Some("emacs".into()), None).unwrap();
        assert_eq!(result, "emacs");
    }

    #[test]
    fn resolve_editor_visual_env() {
        let result = resolve_editor_with_env(None, None, Some("helix".into())).unwrap();
        assert_eq!(result, "helix");
    }

    #[test]
    fn resolve_editor_editor_beats_visual() {
        let result =
            resolve_editor_with_env(None, Some("vim".into()), Some("helix".into())).unwrap();
        assert_eq!(result, "vim");
    }

    #[test]
    fn resolve_editor_empty_env_falls_through_to_fallback() {
        let result = resolve_editor_with_env(None, Some("".into()), None);
        // Either a fallback editor resolves, or a clear error is returned.
        match result {
            Ok(name) => assert_ne!(name, ""),
            Err(TixError::Editor(_)) => {}
            Err(other) => panic!("unexpected error: {other:?}"),
        }
    }

    #[test]
    fn run_editor_success() {
        let tmp = TempDir::new().unwrap();
        let file = tmp.path().join("issue.md");
        fs::write(
            &file,
            "---\nnumber: 1\ntitle: T\nstatus: todo\nlabels: []\npriority: medium\ncreated: \"2026-01-01\"\nupdated: \"2026-01-01\"\n---\n\nbody",
        )
        .unwrap();
        let script = tmp.path().join("edit.sh");
        fs::write(&script, "#!/bin/sh\necho 'done' > /dev/null\n").unwrap();
        Command::new("chmod")
            .arg("+x")
            .arg(&script)
            .status()
            .unwrap();
        let config = Config::default();
        run_editor(script.to_str().unwrap(), &file, &config).unwrap();
    }

    #[test]
    fn run_editor_non_zero_exits_with_error() {
        let tmp = TempDir::new().unwrap();
        let file = tmp.path().join("issue.md");
        fs::write(
            &file,
            "---\nnumber: 1\ntitle: T\nstatus: todo\nlabels: []\npriority: medium\ncreated: \"2026-01-01\"\nupdated: \"2026-01-01\"\n---\n\nbody",
        )
        .unwrap();
        let script = tmp.path().join("fail.sh");
        fs::write(&script, "#!/bin/sh\nexit 1\n").unwrap();
        Command::new("chmod")
            .arg("+x")
            .arg(&script)
            .status()
            .unwrap();
        let config = Config::default();
        let err = run_editor(script.to_str().unwrap(), &file, &config).unwrap_err();
        assert!(matches!(err, TixError::Editor(_)));
    }

    /// `run_editor` runs the editor; it does not own validation (tix #1506).
    ///
    /// The old trailing `Issue::parse` replaced the real diagnostic with the
    /// generic `file not valid after edit`; an editor that leaves an unparsable
    /// file must therefore come back `Ok`, so the caller can classify it.
    #[test]
    fn run_editor_does_not_validate_the_file() {
        let tmp = TempDir::new().unwrap();
        let file = tmp.path().join("issue.md");
        fs::write(&file, "not an issue at all").unwrap();
        let script = tmp.path().join("noop.sh");
        fs::write(&script, "#!/bin/sh\nexit 0\n").unwrap();
        Command::new("chmod")
            .arg("+x")
            .arg(&script)
            .status()
            .unwrap();
        let config = Config::default();
        run_editor(script.to_str().unwrap(), &file, &config).unwrap();
        assert_eq!(fs::read_to_string(&file).unwrap(), "not an issue at all");
    }

    #[test]
    fn resolve_viewer_explicit_override_wins() {
        let result = resolve_viewer_with(Some("mdview"), |_| false).unwrap();
        assert_eq!(result, "mdview");
    }

    #[test]
    fn resolve_viewer_trims_the_override() {
        let result = resolve_viewer_with(Some("  mdview  "), |_| true).unwrap();
        assert_eq!(result, "mdview");
    }

    #[test]
    fn resolve_viewer_blank_override_is_an_error() {
        // Whitespace is neither a program nor "use the chain"; guessing would be
        // worse than saying so.
        let err = resolve_viewer_with(Some("   "), |_| true).unwrap_err();
        assert!(matches!(err, TixError::Editor(_)));
    }

    #[test]
    fn resolve_viewer_follows_the_documented_probe_order() {
        let order = |found: &[&str]| {
            let found = found.to_vec();
            resolve_viewer_with(None, move |name| found.contains(&name)).unwrap()
        };
        assert_eq!(
            order(&["mdterm", "batcat", "most", "less", "more"]),
            "mdterm"
        );
        assert_eq!(order(&["batcat", "most", "less", "more"]), "batcat");
        assert_eq!(order(&["most", "less", "more"]), "most");
        assert_eq!(order(&["less", "more"]), "less");
        assert_eq!(order(&["more"]), "more");
    }

    #[test]
    fn resolve_viewer_auto_uses_the_probe_chain() {
        let found = ["less"];
        let result = resolve_viewer_with(Some("auto"), |name| found.contains(&name)).unwrap();
        assert_eq!(result, "less");
    }

    #[test]
    fn resolve_viewer_none_found_names_every_candidate() {
        let err = resolve_viewer_with(None, |_| false)
            .unwrap_err()
            .to_string();
        for name in VIEWER_CANDIDATES {
            assert!(err.contains(name), "the error must name `{name}`: {err}");
        }
    }

    #[test]
    fn run_viewer_ignores_a_non_zero_exit_and_leaves_the_file_alone() {
        // A pager quits non-zero on an ordinary close; that is not a failure.
        let tmp = TempDir::new().unwrap();
        let file = tmp.path().join("issue.md");
        fs::write(&file, "body").unwrap();
        let script = tmp.path().join("quit.sh");
        fs::write(&script, "#!/bin/sh\nexit 3\n").unwrap();
        Command::new("chmod")
            .arg("+x")
            .arg(&script)
            .status()
            .unwrap();
        run_viewer(script.to_str().unwrap(), &file).unwrap();
        assert_eq!(
            fs::read_to_string(&file).unwrap(),
            "body",
            "the viewer is read-only"
        );
    }

    #[test]
    fn run_viewer_spawn_failure_is_an_error() {
        let tmp = TempDir::new().unwrap();
        let file = tmp.path().join("issue.md");
        fs::write(&file, "body").unwrap();
        let err = run_viewer("tix-no-such-viewer-1507", &file).unwrap_err();
        assert!(matches!(err, TixError::Editor(_)));
    }

    #[test]
    fn merge_fields_flag_driven() {
        let issue = Issue {
            projects: None,
            id: None,
            number: 1,
            title: "Old".into(),
            status: Status::new("todo"),
            labels: vec![],
            priority: Priority::Low,
            assignee: Some("alice".into()),
            estimate: Some("2".into()),
            commit: None,
            gitlab_id: None,
            linear_id: None,
            mission: None,
            task: None,
            relationships: vec![],
            related_issues: vec![],
            files: vec![],
            cycles: None,
            milestones: None,
            reviewer: None,
            start_date: None,
            due_date: None,
            created: "2026-01-01".into(),
            type_: None,
            updated: "2026-01-01".into(),
            filename: String::new(),
            body: "original body".into(),
            history: crate::model::History::new(),
            has_retired_links_key: false,
            time_entries: vec![],
            parent: None,
            series: None,
            health: None,
            epics: None,
            extra_frontmatter: std::collections::BTreeMap::new(),
            archived: false,
            entered_at: None,
            source: None,
        };
        let edits = FieldEdits {
            title: Some("New".into()),
            status: None,
            priority: None,
            labels: None,
            files: None,
            assignee: None,
            estimate: None,
            commit: None,
            cycles: None,
            milestones: None,
            reviewer: None,
            start_date: None,
            due_date: None,
            parent: None,
            related_issues: None,
            type_: None,
        };
        let merged = merge_fields(&issue, &edits);
        assert_eq!(merged.title, "New");
        assert_eq!(merged.status.display(), "todo");
        assert_eq!(merged.body, "original body");
        assert_eq!(merged.assignee.as_deref(), Some("alice"));
    }

    #[test]
    fn merge_fields_commit_clear() {
        let issue = Issue {
            projects: None,
            id: None,
            number: 1,
            title: "T".into(),
            status: Status::new("done"),
            labels: vec![],
            priority: Priority::default(),
            assignee: None,
            estimate: None,
            commit: Some("abc".into()),
            gitlab_id: None,
            linear_id: None,
            mission: None,
            task: None,
            relationships: vec![],
            related_issues: vec![],
            files: vec![],
            cycles: None,
            milestones: None,
            reviewer: None,
            start_date: None,
            due_date: None,
            created: "2026-01-01".into(),
            type_: None,
            updated: "2026-01-01".into(),
            filename: String::new(),
            body: String::new(),
            history: crate::model::History::new(),
            has_retired_links_key: false,
            time_entries: vec![],
            parent: None,
            series: None,
            health: None,
            epics: None,
            extra_frontmatter: std::collections::BTreeMap::new(),
            archived: false,
            entered_at: None,
            source: None,
        };
        let edits = FieldEdits {
            title: None,
            status: Some("in progress".into()),
            priority: None,
            labels: None,
            files: None,
            assignee: None,
            estimate: None,
            commit: Some(None),
            cycles: None,
            milestones: None,
            reviewer: None,
            start_date: None,
            due_date: None,
            parent: None,
            related_issues: None,
            type_: None,
        };
        let merged = merge_fields(&issue, &edits);
        assert!(merged.commit.is_none());
        assert_eq!(merged.status.display(), "in progress");
    }

    #[test]
    fn merge_fields_body_never_altered() {
        let issue = Issue {
            projects: None,
            id: None,
            number: 1,
            title: "T".into(),
            status: Status::new("todo"),
            labels: vec![],
            priority: Priority::default(),
            assignee: None,
            estimate: None,
            commit: None,
            gitlab_id: None,
            linear_id: None,
            mission: None,
            task: None,
            relationships: vec![],
            related_issues: vec![],
            history: crate::model::History::new(),
            has_retired_links_key: false,
            time_entries: vec![],
            parent: None,
            series: None,
            health: None,
            files: vec![],
            cycles: None,
            milestones: None,
            reviewer: None,
            start_date: None,
            due_date: None,
            created: "2026-01-01".into(),
            type_: None,
            updated: "2026-01-01".into(),
            filename: String::new(),
            body: "important body".into(),
            epics: None,
            extra_frontmatter: std::collections::BTreeMap::new(),
            archived: false,
            entered_at: None,
            source: None,
        };
        let edits = FieldEdits {
            title: Some("Changed".into()),
            status: Some("done".into()),
            priority: Some("high".into()),
            labels: Some(vec!["bug".into()]),
            files: Some(vec!["specs/s.md".into()]),
            assignee: Some(Some("bob".into())),
            estimate: Some(Some("3".into())),
            commit: Some(Some("def".into())),
            cycles: Some(Some(vec!["c1".into()])),
            milestones: None,
            reviewer: Some(Some("renata".into())),
            start_date: None,
            due_date: None,
            parent: None,
            related_issues: None,
            type_: None,
        };
        let merged = merge_fields(&issue, &edits);
        assert_eq!(merged.body, "important body");
    }
}