truth-mirror 0.10.1

//! Load live repository state for the TUI without shelling out for reads.

use std::{collections::BTreeMap, fs, path::Path, process::Command};

use anyhow::{Context, Result};

use crate::{
    config::TruthMirrorConfig,
    ledger::{LedgerEntry, LedgerStats, LedgerStore},
    reviewer::{QueuedReview, ReviewQueue, ReviewRunStatusCounts, ReviewRunStore},
    watcher::{self, WatcherLock},
};

use super::model::{
    ConfigRow, DashboardVm, DebtClassGroup, LedgerRow, QueueRow, config_rows, dashboard_vm,
    debt_groups, ledger_rows, queue_rows,
};

/// Point-in-time snapshot of all TUI-visible state.
#[derive(Clone, Debug)]
pub struct Snapshot {
    pub dashboard: DashboardVm,
    pub queue: Vec<QueueRow>,
    pub ledger: Vec<LedgerRow>,
    pub ledger_entries: Vec<LedgerEntry>,
    pub debt: Vec<DebtClassGroup>,
    pub config_rows: Vec<ConfigRow>,
    pub config_raw: String,
    pub stats: LedgerStats,
    pub warnings: Vec<String>,
}

pub fn load_snapshot(
    state_dir: &Path,
    config_path: &Path,
    version: &str,
    subject_cache: &mut BTreeMap<String, String>,
) -> Result<Snapshot> {
    let mut warnings = Vec::new();
    let now = crate::time::unix_now();

    let queue_store = ReviewQueue::new(state_dir);
    let queue_raw = match queue_store.pending() {
        Ok(items) => items,
        Err(error) => {
            warnings.push(format!("queue: {error}"));
            Vec::new()
        }
    };
    let subjects = load_subjects(&queue_raw, subject_cache);
    let queue = queue_rows(&queue_raw, &subjects, now);
    let oldest = queue_raw.iter().map(|item| item.enqueued_at_unix).min();
    let oldest_age = oldest.map(|ts| now.saturating_sub(ts));

    let runs = match ReviewRunStore::new(state_dir).status_counts() {
        Ok(counts) => counts,
        Err(error) => {
            warnings.push(format!("runs: {error}"));
            ReviewRunStatusCounts::default()
        }
    };

    let store = LedgerStore::new(state_dir);
    let (ledger_entries, stats) = match (store.latest_entries(), store.stats()) {
        (Ok(entries), Ok(stats)) => (entries, stats),
        (Err(error), _) => {
            warnings.push(format!("ledger: {error}"));
            (Vec::new(), LedgerStats::default())
        }
        (_, Err(error)) => {
            warnings.push(format!("ledger stats: {error}"));
            (
                store.latest_entries().unwrap_or_default(),
                LedgerStats::default(),
            )
        }
    };
    let ledger = ledger_rows(&ledger_entries, now);

    let flagged = store.flagged_entries().unwrap_or_else(|error| {
        warnings.push(format!("debt: {error}"));
        Vec::new()
    });
    let debt = debt_groups(&flagged, now);

    let (watcher_alive, watcher_pid) = watcher_status(state_dir);

    let (config, config_raw, present_paths) = load_config(config_path, &mut warnings);
    let config_rows = config_rows(&config, &present_paths);

    let config_path_str = config_path.display().to_string();
    let state_dir_str = state_dir.display().to_string();
    let dashboard = dashboard_vm(super::model::DashboardInputs {
        version,
        config_path: &config_path_str,
        state_dir: &state_dir_str,
        queue_pending: queue_raw.len(),
        oldest_age_secs: oldest_age,
        runs: &runs,
        stats: &stats,
        watcher_alive,
        watcher_pid,
    });

    let _ = (config, present_paths);

    Ok(Snapshot {
        dashboard,
        queue,
        ledger,
        ledger_entries,
        debt,
        config_rows,
        config_raw,
        stats,
        warnings,
    })
}

fn watcher_status(state_dir: &Path) -> (bool, Option<u32>) {
    let alive = watcher::watcher_is_alive(state_dir);
    let pid = read_watcher_lock(state_dir).map(|lock| lock.identity.pid);
    (alive, if alive { pid } else { None })
}

fn read_watcher_lock(state_dir: &Path) -> Option<WatcherLock> {
    let path = state_dir.join(watcher::WATCHER_LOCK_FILE);
    let contents = fs::read_to_string(path).ok()?;
    serde_json::from_str(&contents).ok()
}

/// Resolve each queued item's commit subject, reusing `subject_cache` across
/// refreshes. Gemini high (PR #13, data.rs ~138): `load_snapshot` runs on
/// every refresh tick (every 2s by default), and this used to shell out to
/// `git log` for every unique commit in the queue EACH time — a queue that
/// sits still between refreshes still re-spawned one `git` process per
/// commit every 2s forever. A commit's subject is immutable once the commit
/// exists, so caching it by SHA is always safe: no invalidation needed.
fn load_subjects(
    items: &[QueuedReview],
    subject_cache: &mut BTreeMap<String, String>,
) -> BTreeMap<String, String> {
    let mut subjects = BTreeMap::new();
    for item in items {
        if subjects.contains_key(&item.commit_sha) {
            continue;
        }
        if let Some(subject) = subject_cache.get(&item.commit_sha) {
            subjects.insert(item.commit_sha.clone(), subject.clone());
            continue;
        }
        if let Some(subject) = git_subject(&item.commit_sha) {
            subject_cache.insert(item.commit_sha.clone(), subject.clone());
            subjects.insert(item.commit_sha.clone(), subject);
        }
    }
    subjects
}

fn git_subject(sha: &str) -> Option<String> {
    let output = Command::new("git")
        .args(["log", "-1", "--format=%s", sha])
        .output()
        .ok()?;
    if !output.status.success() {
        return None;
    }
    let subject = String::from_utf8_lossy(&output.stdout).trim().to_owned();
    if subject.is_empty() {
        None
    } else {
        Some(subject)
    }
}

fn load_config(
    path: &Path,
    warnings: &mut Vec<String>,
) -> (TruthMirrorConfig, String, BTreeMap<String, bool>) {
    let raw = match fs::read_to_string(path) {
        Ok(contents) => contents,
        Err(error) if error.kind() == std::io::ErrorKind::NotFound => String::new(),
        Err(error) => {
            warnings.push(format!("config read: {error}"));
            String::new()
        }
    };
    let present = present_paths_from_toml(&raw);
    let config = if raw.trim().is_empty() {
        TruthMirrorConfig::default()
    } else {
        match TruthMirrorConfig::from_toml_str(path, &raw) {
            Ok(config) => config,
            Err(error) => {
                warnings.push(format!("config parse: {error}"));
                TruthMirrorConfig::default()
            }
        }
    };
    (config, raw, present)
}

/// Best-effort detection of which dotted paths appear in the raw TOML document.
pub fn present_paths_from_toml(raw: &str) -> BTreeMap<String, bool> {
    let mut present = BTreeMap::new();
    if raw.trim().is_empty() {
        return present;
    }
    let Ok(doc) = raw.parse::<toml_edit::DocumentMut>() else {
        return present;
    };

    mark_key(&mut present, &doc, "ledger_dir");
    mark_key(&mut present, &doc, "allow_same_model");
    mark_key(&mut present, &doc, "default_writer");

    if let Some(table) = doc.get("strict").and_then(|item| item.as_table()) {
        for key in ["stop_after_lies", "stop_after_fuckups", "max_passes"] {
            if table.contains_key(key) {
                present.insert(format!("strict.{key}"), true);
            }
        }
    }
    if let Some(table) = doc.get("gates").and_then(|item| item.as_table()) {
        for key in ["fake_markers", "evidence_patterns", "marker_ignore_paths"] {
            if table.contains_key(key) {
                present.insert(format!("gates.{key}"), true);
            }
        }
    }
    if let Some(table) = doc.get("ground_truth").and_then(|item| item.as_table()) {
        for key in [
            "enabled",
            "max_bytes",
            "include_openspec_specs",
            "file_names",
        ] {
            if table.contains_key(key) {
                present.insert(format!("ground_truth.{key}"), true);
            }
        }
    }
    if let Some(table) = doc.get("history").and_then(|item| item.as_table()) {
        for key in [
            "window_user",
            "window_agent",
            "max_bytes",
            "transcript_path",
        ] {
            if table.contains_key(key) {
                present.insert(format!("history.{key}"), true);
            }
        }
    }
    if let Some(table) = doc.get("enforcement").and_then(|item| item.as_table()) {
        for key in ["block_tools_after_unresolved", "block_tools_after_secs"] {
            if table.contains_key(key) {
                present.insert(format!("enforcement.{key}"), true);
            }
        }
    }
    if let Some(table) = doc.get("skills").and_then(|item| item.as_table())
        && table.contains_key("enabled")
    {
        present.insert("skills.enabled".into(), true);
    }
    if let Some(pairs) = doc.get("pairs").and_then(|item| item.as_table()) {
        for (writer, value) in pairs.iter() {
            let Some(pair) = value.as_table() else {
                continue;
            };
            if let Some(reviewer) = pair.get("reviewer").and_then(|item| item.as_inline_table()) {
                for key in ["harness", "model", "effort"] {
                    if reviewer.contains_key(key) {
                        present.insert(format!("pairs.{writer}.reviewer.{key}"), true);
                    }
                }
            }
            if let Some(reviewer) = pair.get("reviewer").and_then(|item| item.as_table()) {
                for key in ["harness", "model", "effort"] {
                    if reviewer.contains_key(key) {
                        present.insert(format!("pairs.{writer}.reviewer.{key}"), true);
                    }
                }
            }
        }
    }
    present
}

fn mark_key(present: &mut BTreeMap<String, bool>, doc: &toml_edit::DocumentMut, key: &str) {
    if doc.contains_key(key) {
        present.insert(key.to_owned(), true);
    }
}

/// Apply a validated edit to a TOML document, preserving comments where feasible.
pub fn apply_config_edit(raw: &str, path: &str, value: &str) -> Result<String> {
    let mut doc = if raw.trim().is_empty() {
        toml_edit::DocumentMut::new()
    } else {
        raw.parse::<toml_edit::DocumentMut>()
            .context("parse config for edit")?
    };

    set_dotted(&mut doc, path, value)?;
    Ok(doc.to_string())
}

fn set_dotted(doc: &mut toml_edit::DocumentMut, path: &str, value: &str) -> Result<()> {
    let parts: Vec<&str> = path.split('.').collect();
    match parts.as_slice() {
        ["ledger_dir"] => {
            doc["ledger_dir"] = toml_edit::value(value);
        }
        ["allow_same_model"] => {
            doc["allow_same_model"] = toml_edit::value(parse_bool_value(value)?);
        }
        ["default_writer"] => {
            doc["default_writer"] = toml_edit::value(value);
        }
        ["strict", key] => {
            ensure_table(doc, "strict");
            doc["strict"][key] = toml_edit::value(parse_i64(value)?);
        }
        [
            "gates",
            key @ ("fake_markers" | "evidence_patterns" | "marker_ignore_paths"),
        ] => {
            ensure_table(doc, "gates");
            doc["gates"][key] = array_from_csv(value);
        }
        ["ground_truth", "enabled" | "include_openspec_specs"] => {
            ensure_table(doc, "ground_truth");
            doc["ground_truth"][parts[1]] = toml_edit::value(parse_bool_value(value)?);
        }
        ["ground_truth", "max_bytes"] => {
            ensure_table(doc, "ground_truth");
            doc["ground_truth"]["max_bytes"] = toml_edit::value(parse_i64(value)?);
        }
        [
            "history",
            key @ ("window_user" | "window_agent" | "max_bytes"),
        ] => {
            ensure_table(doc, "history");
            doc["history"][key] = toml_edit::value(parse_i64(value)?);
        }
        ["enforcement", key] => {
            ensure_table(doc, "enforcement");
            doc["enforcement"][key] = toml_edit::value(parse_i64(value)?);
        }
        ["skills", "enabled"] => {
            ensure_table(doc, "skills");
            doc["skills"]["enabled"] = toml_edit::value(parse_bool_value(value)?);
        }
        ["pairs", writer, "reviewer", field] => {
            ensure_table(doc, "pairs");
            if doc["pairs"].get(writer).is_none() {
                doc["pairs"][writer] = toml_edit::Item::Table(toml_edit::Table::new());
            }
            if doc["pairs"][writer].get("reviewer").is_none() {
                doc["pairs"][writer]["reviewer"] = toml_edit::Item::Table(toml_edit::Table::new());
            }
            match *field {
                "effort" | "harness" | "model" => {
                    doc["pairs"][writer]["reviewer"][field] = toml_edit::value(value);
                }
                _ => anyhow::bail!("unsupported pair field {field}"),
            }
        }
        _ => anyhow::bail!("unsupported config path: {path}"),
    }
    Ok(())
}

fn ensure_table(doc: &mut toml_edit::DocumentMut, name: &str) {
    if doc.get(name).and_then(|item| item.as_table()).is_none() {
        doc[name] = toml_edit::Item::Table(toml_edit::Table::new());
    }
}

fn parse_bool_value(raw: &str) -> Result<bool> {
    match raw.to_ascii_lowercase().as_str() {
        "true" | "1" | "yes" | "on" => Ok(true),
        "false" | "0" | "no" | "off" => Ok(false),
        _ => anyhow::bail!("expected boolean"),
    }
}

fn parse_i64(raw: &str) -> Result<i64> {
    raw.parse::<i64>().context("expected integer")
}

fn array_from_csv(raw: &str) -> toml_edit::Item {
    let mut arr = toml_edit::Array::new();
    for part in raw.split(',') {
        let trimmed = part.trim();
        if !trimmed.is_empty() {
            arr.push(trimmed);
        }
    }
    toml_edit::value(arr)
}

/// Unified-style line diff for the config save preview.
pub fn line_diff(before: &str, after: &str) -> String {
    let before_lines: Vec<&str> = before.lines().collect();
    let after_lines: Vec<&str> = after.lines().collect();
    let mut out = String::new();
    let max = before_lines.len().max(after_lines.len());
    // Simple LCS-free line walk: emit removals then additions when rows differ.
    let mut i = 0;
    let mut j = 0;
    while i < before_lines.len() || j < after_lines.len() {
        if i < before_lines.len() && j < after_lines.len() && before_lines[i] == after_lines[j] {
            out.push_str("  ");
            out.push_str(before_lines[i]);
            out.push('\n');
            i += 1;
            j += 1;
        } else if j < after_lines.len()
            && (i >= before_lines.len()
                || !after_lines[j..].contains(&before_lines.get(i).copied().unwrap_or("")))
        {
            // Prefer treating unmatched as change pairs when both sides remain.
            if i < before_lines.len()
                && j < after_lines.len()
                && !before_lines[i..].contains(&after_lines[j])
            {
                out.push_str("- ");
                out.push_str(before_lines[i]);
                out.push('\n');
                out.push_str("+ ");
                out.push_str(after_lines[j]);
                out.push('\n');
                i += 1;
                j += 1;
            } else if i < before_lines.len() && before_lines[i..].contains(&after_lines[j]) {
                out.push_str("- ");
                out.push_str(before_lines[i]);
                out.push('\n');
                i += 1;
            } else {
                out.push_str("+ ");
                out.push_str(after_lines[j]);
                out.push('\n');
                j += 1;
            }
        } else if i < before_lines.len() {
            out.push_str("- ");
            out.push_str(before_lines[i]);
            out.push('\n');
            i += 1;
        } else if j < after_lines.len() {
            out.push_str("+ ");
            out.push_str(after_lines[j]);
            out.push('\n');
            j += 1;
        } else {
            break;
        }
        if out.lines().count() > 200 {
            out.push_str("… (diff truncated)\n");
            break;
        }
        let _ = max;
    }
    if out.is_empty() {
        out.push_str("  (no changes)\n");
    }
    out
}

pub fn write_config(path: &Path, contents: &str) -> Result<()> {
    if let Some(parent) = path.parent() {
        fs::create_dir_all(parent)?;
    }
    fs::write(path, contents)?;
    // Validate after write semantics: parse must succeed.
    TruthMirrorConfig::from_toml_str(path, contents).context("written config failed validation")?;
    Ok(())
}

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

    #[test]
    fn present_paths_detects_keys() {
        let raw = r#"
default_writer = "codex"
[strict]
max_passes = 2
"#;
        let present = present_paths_from_toml(raw);
        assert!(present.get("default_writer").copied().unwrap_or(false));
        assert!(present.get("strict.max_passes").copied().unwrap_or(false));
        assert!(!present.get("allow_same_model").copied().unwrap_or(false));
    }

    #[test]
    fn apply_config_edit_preserves_comments() {
        let raw = "# header comment\ndefault_writer = \"codex\"\n";
        let next = apply_config_edit(raw, "default_writer", "claude").unwrap();
        assert!(next.contains("# header comment"));
        assert!(next.contains("default_writer"));
        assert!(next.contains("claude"));
    }

    #[test]
    fn apply_config_edit_bool_and_int() {
        let raw = "";
        let next = apply_config_edit(raw, "allow_same_model", "true").unwrap();
        assert!(next.contains("true"));
        let next = apply_config_edit(&next, "strict.max_passes", "4").unwrap();
        assert!(next.contains("max_passes") && next.contains('4'));
    }

    #[test]
    fn line_diff_marks_changes() {
        let diff = line_diff("a = 1\n", "a = 2\n");
        assert!(diff.contains("- "));
        assert!(diff.contains("+ "));
    }

    #[test]
    fn write_config_round_trips() {
        let dir = tempdir().unwrap();
        let path = dir.path().join("config.toml");
        write_config(&path, "default_writer = \"codex\"\n").unwrap();
        let loaded = fs::read_to_string(&path).unwrap();
        assert!(loaded.contains("codex"));
        assert!(write_config(&path, "this is not = valid toml [[[").is_err());
    }

    fn queued(sha: &str) -> QueuedReview {
        QueuedReview {
            run_id: format!("run-{sha}"),
            commit_sha: sha.to_owned(),
            enqueued_at_unix: 1,
            petition_for: None,
        }
    }

    #[test]
    fn load_subjects_reuses_the_cache_instead_of_reshelling_to_git() {
        // Gemini high (PR #13, data.rs ~138): `load_subjects` used to call
        // `git log` for every unique commit sha on EVERY refresh (every 2s by
        // default), even when the queue hadn't changed. A commit's subject is
        // immutable, so it only ever needs to be resolved once per sha.
        // Planting a sentinel value directly in the cache (one `git log`
        // could never produce) and confirming it comes back unchanged proves
        // the second call read from the cache rather than re-shelling.
        let sha = "0123456789abcdef0123456789abcdef01234567";
        let items = vec![queued(sha)];
        let mut cache = BTreeMap::new();

        cache.insert(
            sha.to_owned(),
            "sentinel-subject-no-real-git-log-would-ever-produce".to_owned(),
        );
        let subjects = load_subjects(&items, &mut cache);

        assert_eq!(
            subjects.get(sha).map(String::as_str),
            Some("sentinel-subject-no-real-git-log-would-ever-produce"),
            "a cached subject must be reused, not re-resolved via git"
        );
        assert_eq!(
            cache.len(),
            1,
            "the cache must not grow when the entry was already present"
        );
    }

    #[test]
    fn load_subjects_populates_the_cache_for_a_real_commit() {
        // The other half of the caching contract: a sha resolved for the
        // first time must land in the cache so the NEXT refresh can reuse it
        // instead of shelling out again.
        let sha = {
            let out = std::process::Command::new("git")
                .args(["rev-parse", "HEAD"])
                .output()
                .expect("git rev-parse HEAD");
            String::from_utf8(out.stdout).unwrap().trim().to_owned()
        };
        let items = vec![queued(&sha)];
        let mut cache = BTreeMap::new();

        let subjects = load_subjects(&items, &mut cache);

        assert!(
            subjects.contains_key(&sha),
            "a resolvable commit must appear in the returned subjects"
        );
        assert_eq!(
            cache.get(&sha),
            subjects.get(&sha),
            "a freshly resolved subject must be recorded in the cache"
        );
    }
}