truth_mirror/

hooks.rs

//! Hook installation, uninstallation, and dry-run planning.

use std::{
    fs,
    io::{self, Read},
    path::{Path, PathBuf},
    process::{Command, ExitCode},
};

use anyhow::{Context, Result, bail};

use crate::{
    claim,
    cli::{self, Agent, HookName},
    gate,
    reviewer::ReviewQueue,
    surface::{self, SurfacePlan},
};

const INSTALLED_HOOKS: &[HookName] =
    &[HookName::CommitMsg, HookName::PostCommit, HookName::PrePush];
const MANAGED_MARKER: &str = "# truth-mirror managed hook";
const MANAGED_END_MARKER: &str = "# truth-mirror hook end";
const HUSKY_ENTIRE_BRIDGE_MARKER: &str = "# Bridge for the husky+entire chain";
const FORWARDER_NAME: &str = "_forward-local.sh";
const OUTER_HOOK_MARKERS: &[&str] = &[
    "# Entire CLI hooks",
    HUSKY_ENTIRE_BRIDGE_MARKER,
    "# truth-mirror managed hook",
    "exec truth-mirror",
    "entire hooks git",
];
const STATE_GITIGNORE_HEADER: &str = "# truth-mirror runtime state - machine-generated";
const STATE_GITIGNORE_LINES: &[&str] =
    &["runs/", "review-queue.jsonl", "tmp/", "logs/", "*.local.*"];
const FORWARDER_SOURCE: &str = r#"#!/bin/sh
# _forward-local.sh - delegate to .git/hooks from a committed core.hooksPath.
# Uses --git-common-dir (resolves to .git/) not core.hooksPath to prevent an infinite loop.
name="$1"; shift
git_dir="$(git rev-parse --git-common-dir 2>/dev/null)"
[ -n "$git_dir" ] || exit 0
local_hook="$git_dir/hooks/$name"
if [ -x "$local_hook" ]; then exec "$local_hook" "$@"; fi
exit 0
"#;

/// Printed after `--pi` install: Pi only executes project extensions once the
/// folder is trusted (verified against Pi 0.80.3 `core/project-trust.js`).
const PI_TRUST_NOTE: &str = "pi: installed .pi/extensions/truth-mirror.js — Pi loads it once you trust this project folder in Pi.";

pub fn run(
    args: cli::InstallHooksArgs,
    state_dir: &Path,
    config_path: Option<&Path>,
    config: &crate::config::TruthMirrorConfig,
) -> Result<ExitCode> {
    let repo_root = git_root()?;
    let hooks_path = repo_root.join(state_dir).join("hooks");
    let plan = HookInstallPlan::new(&repo_root, &hooks_path, args.uninstall);
    // Preserve non-default global flags so the INSTALLED hooks use the same config
    // and state dir at runtime instead of silently reloading defaults.
    let global_args = hook_global_args(config_path, &repo_root, state_dir);
    let plan = HookInstallPlan {
        global_args,
        mode: detect_hook_mode(&repo_root, state_dir)?,
        ..plan
    };
    let agents = file_surface_agents(&args);
    let pi = pi_targeted(&args);

    if args.dry_run {
        println!("{}", plan.render());
        for agent in &agents {
            println!(
                "surface: {} -> {}",
                surface::agent_slug(*agent),
                surface::surface_relative_path(*agent)
            );
        }
        if pi {
            println!("surface: pi -> {}", surface::PI_EXTENSION_RELATIVE);
        }
        return Ok(ExitCode::SUCCESS);
    }

    let enforcement_enabled = config.enforcement.is_enabled();

    if args.uninstall {
        uninstall(&plan)?;
        for agent in &agents {
            surface::uninstall_enforcement(&repo_root, *agent)?;
            SurfacePlan::for_agent(&repo_root, *agent).uninstall()?;
        }
        if pi {
            surface::uninstall_pi_extension(&repo_root)?;
            remove_legacy_pi_hooks(&repo_root)?;
        }
    } else {
        install(&plan, args.inject_forwarder)?;
        for agent in &agents {
            SurfacePlan::for_agent(&repo_root, *agent).install()?;
            // Enforcement is opt-in: only install the tool-blocking hook when the
            // repo config enables it. Preserve global flags so it uses this config.
            if enforcement_enabled {
                surface::install_enforcement(&repo_root, *agent, &plan.global_args)?;
            }
        }
        if args.pi {
            // Clean any bogus .pi/hooks.json a prior truth-mirror wrote, install the
            // real project-local extension, and note the one-time trust step.
            remove_legacy_pi_hooks(&repo_root)?;
            surface::install_pi_extension(&repo_root)?;
            println!("{PI_TRUST_NOTE}");
        }
    }

    Ok(ExitCode::SUCCESS)
}

/// File-surface agents (Claude, Codex) touched by this invocation. Install acts
/// only on explicitly selected agents; a bare `install-hooks --uninstall` clears
/// all file surfaces so it fully reverses a prior per-agent install.
fn file_surface_agents(args: &cli::InstallHooksArgs) -> Vec<Agent> {
    let mut agents = Vec::new();
    if args.claude {
        agents.push(Agent::Claude);
    }
    if args.codex {
        agents.push(Agent::Codex);
    }

    if agents.is_empty() && args.uninstall && !args.pi {
        return surface::FILE_SURFACE_AGENTS.to_vec();
    }
    agents
}

/// Whether this invocation should act on Pi: explicit `--pi`, or a bare
/// `--uninstall` (no agent flags) that clears everything including legacy Pi files.
fn pi_targeted(args: &cli::InstallHooksArgs) -> bool {
    args.pi || (args.uninstall && !args.claude && !args.codex)
}

/// Remove a `.pi/hooks.json` left by an earlier (incorrect) truth-mirror version.
fn remove_legacy_pi_hooks(repo_root: &Path) -> Result<()> {
    let path = repo_root.join(".pi/hooks.json");
    if path.is_file() {
        fs::remove_file(&path)?;
    }
    Ok(())
}

pub fn dispatch(
    args: cli::HookDispatchArgs,
    state_dir: &Path,
    config: &crate::config::TruthMirrorConfig,
) -> Result<ExitCode> {
    run_chained_hook(state_dir, args.hook, &args.args)?;

    match args.hook {
        HookName::CommitMsg => dispatch_commit_msg(state_dir, &args.args, config)?,
        HookName::PostCommit => dispatch_post_commit(state_dir)?,
        HookName::PrePush => dispatch_pre_push(state_dir, config)?,
    }

    Ok(ExitCode::SUCCESS)
}

#[derive(Clone, Debug, Default, Eq, PartialEq)]
pub struct HookInstallPlan {
    pub repo_root: PathBuf,
    pub hooks_path: PathBuf,
    pub uninstall: bool,
    pub mode: HookInstallMode,
    /// Global CLI flags (`--config`, `--state-dir`) preserved into the shims so a
    /// custom-config install keeps using that config at hook runtime. Empty for a
    /// default install (the trailing space is included when non-empty).
    pub global_args: String,
}

#[derive(Clone, Debug, Default, Eq, PartialEq)]
pub enum HookInstallMode {
    #[default]
    Plain,
    LegacyTruthMirrorHooksPath {
        configured_path: String,
    },
    Husky {
        content_dir: PathBuf,
    },
    CustomCommitted {
        hooks_path: PathBuf,
    },
}

impl HookInstallPlan {
    pub fn new(repo_root: &Path, hooks_path: &Path, uninstall: bool) -> Self {
        Self {
            repo_root: repo_root.to_path_buf(),
            hooks_path: hooks_path.to_path_buf(),
            uninstall,
            mode: HookInstallMode::Plain,
            global_args: String::new(),
        }
    }

    pub fn render(&self) -> String {
        let action = if self.uninstall {
            "uninstall"
        } else {
            "install"
        };
        let mut output = format!(
            "truth-mirror hook plan\nrepo={}\naction={action}\nmode={}\nstateHooks={}\n",
            self.repo_root.display(),
            self.mode.as_str(),
            self.hooks_path.display()
        );
        for hook in INSTALLED_HOOKS {
            output.push_str(&format!(
                "\nhook={}\npath={}\nbody:\n{}",
                hook.as_str(),
                self.active_hook_path(*hook).display(),
                self.render_hook_body(*hook)
            ));
            if let HookInstallMode::Husky { content_dir } = &self.mode {
                output.push_str(&format!(
                    "\nbridge={}.pre-entire\npath={}\nbody:\n{}",
                    hook.as_str(),
                    husky_entire_bridge_path(content_dir, *hook).display(),
                    render_husky_entire_bridge(*hook)
                ));
            }
        }
        output
    }

    fn active_hook_path(&self, hook: HookName) -> PathBuf {
        match &self.mode {
            HookInstallMode::Husky { content_dir } => content_dir.join(hook.as_str()),
            HookInstallMode::Plain | HookInstallMode::LegacyTruthMirrorHooksPath { .. } => {
                self.repo_root.join(".git/hooks").join(hook.as_str())
            }
            HookInstallMode::CustomCommitted { hooks_path } => hooks_path.join(hook.as_str()),
        }
    }

    fn render_hook_body(&self, hook: HookName) -> String {
        match self.mode {
            HookInstallMode::Husky { .. } => render_husky_block(hook, &self.global_args),
            HookInstallMode::CustomCommitted { .. } => render_custom_forwarder_stub(hook),
            HookInstallMode::Plain | HookInstallMode::LegacyTruthMirrorHooksPath { .. } => {
                render_shim(hook, &self.global_args)
            }
        }
    }
}

impl HookInstallMode {
    fn as_str(&self) -> &'static str {
        match self {
            HookInstallMode::Plain => "plain",
            HookInstallMode::LegacyTruthMirrorHooksPath { .. } => "plain-legacy-truth-mirror",
            HookInstallMode::Husky { .. } => "husky",
            HookInstallMode::CustomCommitted { .. } => "custom-committed",
        }
    }
}

/// Build the preserved global-flag prefix (with a trailing space when non-empty).
fn hook_global_args(config_path: Option<&Path>, repo_root: &Path, state_dir: &Path) -> String {
    let mut parts = Vec::new();
    if let Some(config) = config_path {
        parts.push(format!(
            "--config {}",
            quote_git_arg(&absolutize(repo_root, config))
        ));
    }
    if state_dir != Path::new(crate::config::DEFAULT_STATE_DIR) {
        parts.push(format!(
            "--state-dir {}",
            quote_git_arg(&absolutize(repo_root, state_dir))
        ));
    }
    if parts.is_empty() {
        String::new()
    } else {
        format!("{} ", parts.join(" "))
    }
}

fn absolutize(repo_root: &Path, path: &Path) -> PathBuf {
    if path.is_absolute() {
        path.to_path_buf()
    } else {
        repo_root.join(path)
    }
}

/// POSIX single-quote escaping for a path embedded in the generated `/bin/sh`
/// shim: wrap in single quotes and replace any embedded single quote with `'\''`
/// so no metacharacter (`;`, `$()`, `'`, spaces, …) can break or inject shell.
fn quote_git_arg(path: &Path) -> String {
    let value = path.to_string_lossy();
    format!("'{}'", value.replace('\'', "'\\''"))
}

pub fn render_shim(hook: HookName, global_args: &str) -> String {
    format!(
        "#!/bin/sh\n{MANAGED_MARKER}\nexec truth-mirror {global_args}hook-dispatch {} \"$@\"\n",
        hook.as_str()
    )
}

fn render_husky_block(hook: HookName, global_args: &str) -> String {
    format!(
        "{MANAGED_MARKER}\nif command -v truth-mirror >/dev/null 2>&1; then truth-mirror {global_args}hook-dispatch {} \"$@\"; else :; fi\n{MANAGED_END_MARKER}\n",
        hook.as_str()
    )
}

fn render_husky_entire_bridge(hook: HookName) -> String {
    format!(
        "#!/bin/sh\n{HUSKY_ENTIRE_BRIDGE_MARKER}\n{}\n",
        husky_entire_bridge_exec_line(hook)
    )
}

fn husky_entire_bridge_exec_line(hook: HookName) -> String {
    format!("exec \"$(dirname \"$0\")/{}\" \"$@\"", hook.as_str())
}

fn render_custom_forwarder_stub(hook: HookName) -> String {
    format!(
        "#!/bin/sh\n{MANAGED_MARKER}\nexec \"$(dirname \"$0\")/{FORWARDER_NAME}\" {} \"$@\"\n",
        hook.as_str()
    )
}

fn detect_hook_mode(repo_root: &Path, state_dir: &Path) -> Result<HookInstallMode> {
    let Some(configured) = git_config_get(repo_root, "core.hooksPath")? else {
        return Ok(HookInstallMode::Plain);
    };
    let configured = configured.trim().to_owned();
    if configured.is_empty() {
        return Ok(HookInstallMode::Plain);
    }
    if is_managed_hooks_path(repo_root, state_dir, &configured) {
        return Ok(HookInstallMode::LegacyTruthMirrorHooksPath {
            configured_path: configured,
        });
    }
    if configured.contains(".husky") {
        let hooks_path = repo_relative_path(repo_root, Path::new(&configured));
        let content_dir = if hooks_path.file_name().and_then(|name| name.to_str()) == Some("_") {
            hooks_path
                .parent()
                .map_or_else(|| repo_root.join(".husky"), Path::to_path_buf)
        } else {
            hooks_path
        };
        return Ok(HookInstallMode::Husky { content_dir });
    }
    Ok(HookInstallMode::CustomCommitted {
        hooks_path: repo_relative_path(repo_root, Path::new(&configured)),
    })
}

fn repo_relative_path(repo_root: &Path, path: &Path) -> PathBuf {
    if path.is_absolute() {
        path.to_path_buf()
    } else {
        repo_root.join(path)
    }
}

fn is_managed_hooks_path(repo_root: &Path, state_dir: &Path, configured: &str) -> bool {
    [
        state_dir.join("hooks"),
        PathBuf::from(crate::config::DEFAULT_STATE_DIR).join("hooks"),
        PathBuf::from(crate::config::LEGACY_STATE_DIR).join("hooks"),
    ]
    .iter()
    .any(|candidate| path_config_matches(repo_root, candidate, configured))
}

fn path_config_matches(repo_root: &Path, candidate: &Path, configured: &str) -> bool {
    let candidate_string = candidate.to_string_lossy().into_owned();
    let absolute_string = repo_root.join(candidate).to_string_lossy().into_owned();
    configured == candidate_string || configured == absolute_string
}

fn install(plan: &HookInstallPlan, inject_forwarder: bool) -> Result<()> {
    match &plan.mode {
        HookInstallMode::Plain => {
            prepare_state_hooks(plan)?;
            install_plain(plan)
        }
        HookInstallMode::LegacyTruthMirrorHooksPath { .. } => {
            prepare_state_hooks(plan)?;
            unset_core_hooks_path(&plan.repo_root)?;
            install_plain(plan)
        }
        HookInstallMode::Husky { content_dir } => {
            prepare_state_hooks(plan)?;
            install_husky(plan, content_dir)
        }
        HookInstallMode::CustomCommitted { hooks_path } => {
            install_custom(plan, hooks_path, inject_forwarder)
        }
    }
}

fn uninstall(plan: &HookInstallPlan) -> Result<()> {
    match &plan.mode {
        HookInstallMode::Plain => uninstall_plain(plan)?,
        HookInstallMode::LegacyTruthMirrorHooksPath { .. } => {
            unset_core_hooks_path(&plan.repo_root)?;
            uninstall_plain(plan)?;
        }
        HookInstallMode::Husky { content_dir } => uninstall_husky(plan, content_dir)?,
        HookInstallMode::CustomCommitted { hooks_path } => {
            uninstall_plain(plan)?;
            uninstall_custom_forwarders(hooks_path)?;
        }
    }

    if plan.hooks_path.exists() {
        fs::remove_dir_all(&plan.hooks_path)?;
    }
    Ok(())
}

fn state_dir_from_hooks_path(hooks_path: &Path) -> &Path {
    hooks_path.parent().unwrap_or(hooks_path)
}

fn prepare_state_hooks(plan: &HookInstallPlan) -> Result<()> {
    ensure_state_gitignore(&plan.repo_root, state_dir_from_hooks_path(&plan.hooks_path))?;
    fs::create_dir_all(&plan.hooks_path)?;
    fs::create_dir_all(plan.hooks_path.join("chained"))?;
    clear_chained_hooks(plan)
}

fn install_plain(plan: &HookInstallPlan) -> Result<()> {
    let git_hooks = plan.repo_root.join(".git/hooks");
    fs::create_dir_all(&git_hooks)?;
    for hook in INSTALLED_HOOKS {
        install_local_hook(plan, &git_hooks, *hook)?;
    }
    Ok(())
}

fn install_local_hook(plan: &HookInstallPlan, git_hooks: &Path, hook: HookName) -> Result<()> {
    let active = git_hooks.join(hook.as_str());
    let backup = backup_path(&active, "pre-truth-mirror");
    let chained = plan.hooks_path.join("chained").join(hook.as_str());
    remove_file_if_exists(&chained)?;

    let source = local_hook_source(&active, &backup)?;
    if let Some(source) = source {
        if source.path != backup {
            fs::copy(&source.path, &backup)?;
            make_executable(&backup)?;
        }
        if !has_outer_hook_marker(&source.content) {
            fs::copy(&source.path, &chained)?;
            make_executable(&chained)?;
        }
    }

    fs::write(&active, render_shim(hook, &plan.global_args))?;
    make_executable(&active)?;
    Ok(())
}

fn uninstall_plain(plan: &HookInstallPlan) -> Result<()> {
    let git_hooks = plan.repo_root.join(".git/hooks");
    for hook in INSTALLED_HOOKS {
        let active = git_hooks.join(hook.as_str());
        let backup = backup_path(&active, "pre-truth-mirror");
        let active_content = read_to_string_if_file(&active)?;
        if active_content
            .as_deref()
            .is_some_and(is_truth_mirror_managed)
        {
            if backup.is_file() {
                fs::copy(&backup, &active)?;
                make_executable(&active)?;
                fs::remove_file(&backup)?;
            } else {
                remove_file_if_exists(&active)?;
            }
        }
        remove_file_if_exists(&plan.hooks_path.join("chained").join(hook.as_str()))?;
    }
    Ok(())
}

fn install_husky(plan: &HookInstallPlan, content_dir: &Path) -> Result<()> {
    fs::create_dir_all(content_dir)?;
    for hook in INSTALLED_HOOKS {
        let target = content_dir.join(hook.as_str());
        let block = render_husky_block(*hook, &plan.global_args);
        let next = match read_to_string_if_file(&target)? {
            Some(content) => append_managed_block(&content, &block),
            None => format!("#!/bin/sh\n{block}"),
        };
        fs::write(&target, next)?;
        make_executable(&target)?;
        install_husky_entire_bridge(content_dir, *hook)?;
    }
    Ok(())
}

fn install_husky_entire_bridge(content_dir: &Path, hook: HookName) -> Result<()> {
    let target = husky_entire_bridge_path(content_dir, hook);
    let backup = backup_path(&target, "pre-truth-mirror");
    if let Some(content) = read_to_string_if_file(&target)? {
        if is_husky_entire_bridge(&content) && has_husky_entire_bridge_exec(&content, hook) {
            make_executable(&target)?;
            return Ok(());
        }
        if !is_husky_entire_bridge(&content) {
            fs::copy(&target, &backup)?;
            make_executable(&backup)?;
        }
    }
    fs::write(&target, render_husky_entire_bridge(hook))?;
    make_executable(&target)?;
    Ok(())
}

fn uninstall_husky(_plan: &HookInstallPlan, content_dir: &Path) -> Result<()> {
    for hook in INSTALLED_HOOKS {
        let target = content_dir.join(hook.as_str());
        if let Some(content) = read_to_string_if_file(&target)? {
            let next = remove_managed_block(&content);
            if is_empty_or_shebang_only(&next) {
                fs::remove_file(&target)?;
            } else {
                fs::write(&target, next)?;
                make_executable(&target)?;
            }
        }
        uninstall_husky_entire_bridge(content_dir, *hook)?;
    }
    Ok(())
}

fn uninstall_husky_entire_bridge(content_dir: &Path, hook: HookName) -> Result<()> {
    let target = husky_entire_bridge_path(content_dir, hook);
    let backup = backup_path(&target, "pre-truth-mirror");
    match read_to_string_if_file(&target)? {
        Some(content) if is_husky_entire_bridge(&content) => {
            if backup.is_file() {
                fs::copy(&backup, &target)?;
                make_executable(&target)?;
                fs::remove_file(&backup)?;
            } else {
                remove_file_if_exists(&target)?;
            }
        }
        None if backup.is_file() => {
            fs::copy(&backup, &target)?;
            make_executable(&target)?;
            fs::remove_file(&backup)?;
        }
        _ => {}
    }
    Ok(())
}

fn husky_entire_bridge_path(content_dir: &Path, hook: HookName) -> PathBuf {
    content_dir.join(format!("{}.pre-entire", hook.as_str()))
}

fn install_custom(plan: &HookInstallPlan, hooks_path: &Path, inject_forwarder: bool) -> Result<()> {
    let missing_forwarder = INSTALLED_HOOKS
        .iter()
        .any(|hook| !custom_forwarder_present(hooks_path, *hook));
    if missing_forwarder && !inject_forwarder {
        bail!(
            "truth-mirror: core.hooksPath is set to '{}' (a non-husky committed directory).\nTo install, either:\n  (a) run `truth-mirror install-hooks --inject-forwarder` to write a _forward-local.sh forwarder into that directory (a committed repo change), or\n  (b) unset core.hooksPath and re-run install-hooks",
            hooks_path.display()
        );
    }

    if inject_forwarder {
        inject_custom_forwarders(hooks_path)?;
    }

    prepare_state_hooks(plan)?;
    let git_hooks = plan.repo_root.join(".git/hooks");
    fs::create_dir_all(&git_hooks)?;
    for hook in INSTALLED_HOOKS {
        install_local_hook(plan, &git_hooks, *hook)?;
    }
    Ok(())
}

fn inject_custom_forwarders(hooks_path: &Path) -> Result<()> {
    fs::create_dir_all(hooks_path)?;
    let forwarder = hooks_path.join(FORWARDER_NAME);
    fs::write(&forwarder, FORWARDER_SOURCE)?;
    make_executable(&forwarder)?;

    for hook in INSTALLED_HOOKS {
        let target = hooks_path.join(hook.as_str());
        if custom_forwarder_present(hooks_path, *hook) {
            continue;
        }
        if target.is_file() {
            fs::copy(&target, backup_path(&target, "pre-truth-mirror"))?;
        }
        fs::write(&target, render_custom_forwarder_stub(*hook))?;
        make_executable(&target)?;
    }
    eprintln!(
        "hint: commit the truth-mirror forwarder changes in {}",
        hooks_path.display()
    );
    Ok(())
}

fn uninstall_custom_forwarders(hooks_path: &Path) -> Result<()> {
    for hook in INSTALLED_HOOKS {
        let target = hooks_path.join(hook.as_str());
        let backup = backup_path(&target, "pre-truth-mirror");
        let content = read_to_string_if_file(&target)?;
        if content.as_deref().is_some_and(is_truth_mirror_managed) {
            if backup.is_file() {
                fs::copy(&backup, &target)?;
                make_executable(&target)?;
                fs::remove_file(&backup)?;
            } else {
                remove_file_if_exists(&target)?;
            }
        }
    }
    let forwarder = hooks_path.join(FORWARDER_NAME);
    if read_to_string_if_file(&forwarder)?.as_deref() == Some(FORWARDER_SOURCE) {
        fs::remove_file(forwarder)?;
    }
    Ok(())
}

fn append_managed_block(content: &str, block: &str) -> String {
    let mut next = remove_managed_block(content);
    if !next.ends_with('\n') {
        next.push('\n');
    }
    next.push_str(block);
    next
}

fn remove_managed_block(content: &str) -> String {
    let mut out = Vec::new();
    let mut skipping = false;
    for line in content.lines() {
        if line == MANAGED_MARKER {
            skipping = true;
            continue;
        }
        if skipping {
            if line == MANAGED_END_MARKER {
                skipping = false;
            }
            continue;
        }
        out.push(line);
    }
    if out.is_empty() {
        String::new()
    } else {
        format!("{}\n", out.join("\n"))
    }
}

fn is_empty_or_shebang_only(content: &str) -> bool {
    let lines = content
        .lines()
        .map(str::trim)
        .filter(|line| !line.is_empty())
        .collect::<Vec<_>>();
    lines.is_empty() || lines == ["#!/bin/sh"]
}

#[derive(Debug)]
struct LocalHookSource {
    path: PathBuf,
    content: String,
}

fn local_hook_source(active: &Path, backup: &Path) -> Result<Option<LocalHookSource>> {
    let Some(active_content) = read_to_string_if_file(active)? else {
        return Ok(None);
    };
    if is_truth_mirror_managed(&active_content) {
        return read_to_string_if_file(backup)?.map_or(Ok(None), |content| {
            Ok(Some(LocalHookSource {
                path: backup.to_path_buf(),
                content,
            }))
        });
    }
    Ok(Some(LocalHookSource {
        path: active.to_path_buf(),
        content: active_content,
    }))
}

fn custom_forwarder_present(hooks_path: &Path, hook: HookName) -> bool {
    read_to_string_if_file(&hooks_path.join(hook.as_str()))
        .ok()
        .flatten()
        .is_some_and(|content| {
            content.contains("--git-common-dir")
                || content.contains(FORWARDER_NAME)
                || is_truth_mirror_managed(&content)
        })
}

fn ensure_state_gitignore(repo_root: &Path, state_dir: &Path) -> Result<()> {
    let state_dir = absolutize(repo_root, state_dir);
    fs::create_dir_all(&state_dir)?;
    let gitignore = state_dir.join(".gitignore");
    let mut content = read_to_string_if_file(&gitignore)?.unwrap_or_default();
    if content.is_empty() {
        content.push_str(STATE_GITIGNORE_HEADER);
        content.push('\n');
    }
    for line in STATE_GITIGNORE_LINES {
        if !content.lines().any(|existing| existing.trim() == *line) {
            if !content.ends_with('\n') {
                content.push('\n');
            }
            content.push_str(line);
            content.push('\n');
        }
    }
    fs::write(&gitignore, content)?;
    print_tracked_runtime_hints(repo_root, &state_dir)?;
    Ok(())
}

fn print_tracked_runtime_hints(repo_root: &Path, state_dir: &Path) -> Result<()> {
    let rel_state = state_dir.strip_prefix(repo_root).unwrap_or(state_dir);
    for path in [
        rel_state.join("review-queue.jsonl"),
        rel_state.join("runs"),
        rel_state.join("tmp"),
        rel_state.join("logs"),
    ] {
        let output = Command::new("git")
            .args(["ls-files", "--"])
            .arg(&path)
            .current_dir(repo_root)
            .output()?;
        if output.status.success() {
            for tracked in String::from_utf8_lossy(&output.stdout)
                .lines()
                .filter(|line| !line.trim().is_empty())
            {
                eprintln!("hint: run: git rm --cached {tracked}");
            }
        }
    }
    Ok(())
}

fn clear_chained_hooks(plan: &HookInstallPlan) -> Result<()> {
    for hook in INSTALLED_HOOKS {
        remove_file_if_exists(&plan.hooks_path.join("chained").join(hook.as_str()))?;
    }
    Ok(())
}

fn has_outer_hook_marker(content: &str) -> bool {
    content.lines().take(20).any(|line| {
        OUTER_HOOK_MARKERS
            .iter()
            .any(|marker| line.contains(marker))
    })
}

fn is_truth_mirror_managed(content: &str) -> bool {
    content.contains(MANAGED_MARKER)
        || content.contains(HUSKY_ENTIRE_BRIDGE_MARKER)
        || content.contains("exec truth-mirror")
}

fn is_husky_entire_bridge(content: &str) -> bool {
    content.contains(HUSKY_ENTIRE_BRIDGE_MARKER)
}

fn has_husky_entire_bridge_exec(content: &str, hook: HookName) -> bool {
    let expected = husky_entire_bridge_exec_line(hook);
    content.lines().any(|line| line.trim() == expected)
}

fn backup_path(path: &Path, suffix: &str) -> PathBuf {
    let file_name = path
        .file_name()
        .and_then(|name| name.to_str())
        .unwrap_or("hook");
    path.with_file_name(format!("{file_name}.{suffix}"))
}

fn read_to_string_if_file(path: &Path) -> Result<Option<String>> {
    match fs::read_to_string(path) {
        Ok(content) => Ok(Some(content)),
        Err(error) if error.kind() == io::ErrorKind::NotFound => Ok(None),
        Err(error) => Err(error.into()),
    }
}

fn remove_file_if_exists(path: &Path) -> Result<()> {
    match fs::remove_file(path) {
        Ok(()) => Ok(()),
        Err(error) if error.kind() == io::ErrorKind::NotFound => Ok(()),
        Err(error) => Err(error.into()),
    }
}

fn unset_core_hooks_path(repo_root: &Path) -> Result<()> {
    let status = Command::new("git")
        .args(["config", "--unset", "core.hooksPath"])
        .current_dir(repo_root)
        .status()?;
    if !status.success() {
        // Git exits non-zero when the key is already absent; migration should be idempotent.
        return Ok(());
    }
    Ok(())
}

fn dispatch_commit_msg(
    state_dir: &Path,
    args: &[String],
    config: &crate::config::TruthMirrorConfig,
) -> Result<()> {
    let commit_msg_path = args
        .first()
        .context("commit-msg hook requires COMMIT_EDITMSG path")?;
    let commit_message = fs::read_to_string(commit_msg_path)?;
    let diff = git_stdout(&["diff", "--cached"])?;
    let claim_file = fs::read_to_string(state_dir.join("claim.txt")).ok();
    let policy = config.gates.to_policy();
    claim::evaluate_commit_message(&commit_message, claim_file.as_deref(), Some(&diff), &policy)?;
    Ok(())
}

fn dispatch_post_commit(state_dir: &Path) -> Result<()> {
    let sha = git_stdout(&["rev-parse", "HEAD"])?;
    ReviewQueue::new(state_dir).enqueue(sha.trim())?;
    Ok(())
}

fn dispatch_pre_push(state_dir: &Path, config: &crate::config::TruthMirrorConfig) -> Result<()> {
    let mut stdin = String::new();
    io::stdin().read_to_string(&mut stdin)?;
    for line in stdin.lines() {
        if let Some(range) = pre_push_range_from_line(line) {
            gate::run(
                cli::GateArgs {
                    pre_push: Some(range),
                    commit_msg: None,
                    claim_file: None,
                    diff_file: None,
                    fake_markers: Vec::new(),
                    pre_tool_use: false,
                    tool: None,
                },
                state_dir,
                config,
            )?;
        }
    }
    Ok(())
}

fn pre_push_range_from_line(line: &str) -> Option<String> {
    let parts = line.split_whitespace().collect::<Vec<_>>();
    let local_sha = parts.get(1)?;
    let remote_sha = parts.get(3)?;
    if is_zero_sha(local_sha) {
        return None;
    }

    if is_zero_sha(remote_sha) {
        Some((*local_sha).to_owned())
    } else {
        Some(format!("{remote_sha}..{local_sha}"))
    }
}

fn is_zero_sha(value: &str) -> bool {
    value.chars().all(|character| character == '0')
}

fn run_chained_hook(state_dir: &Path, hook: HookName, args: &[String]) -> Result<()> {
    let chained = state_dir.join("hooks/chained").join(hook.as_str());
    if !chained.is_file() {
        return Ok(());
    }
    let content = fs::read_to_string(&chained)?;
    if has_outer_hook_marker(&content) {
        eprintln!(
            "truth-mirror: skipping unsafe chained hook {} because it appears to invoke an outer hook manager",
            chained.display()
        );
        return Ok(());
    }

    let status = Command::new(&chained).args(args).status()?;
    if !status.success() {
        bail!(
            "chained hook {} failed with status {status}",
            chained.display()
        );
    }
    Ok(())
}

fn git_root() -> Result<PathBuf> {
    Ok(PathBuf::from(
        git_stdout(&["rev-parse", "--show-toplevel"])?.trim(),
    ))
}

fn git_stdout(args: &[&str]) -> Result<String> {
    let output = Command::new("git").args(args).output()?;
    if !output.status.success() {
        bail!(
            "git {} failed: {}",
            args.join(" "),
            String::from_utf8_lossy(&output.stderr)
        );
    }
    Ok(String::from_utf8_lossy(&output.stdout).into_owned())
}

fn git_config_get(repo_root: &Path, key: &str) -> Result<Option<String>> {
    let output = Command::new("git")
        .args(["config", "--get", key])
        .current_dir(repo_root)
        .output()?;
    if output.status.success() {
        return Ok(Some(String::from_utf8_lossy(&output.stdout).into_owned()));
    }
    if output.status.code() == Some(1) {
        return Ok(None);
    }
    bail!(
        "git config --get {key} failed: {}",
        String::from_utf8_lossy(&output.stderr)
    );
}

#[cfg(unix)]
fn make_executable(path: &Path) -> Result<()> {
    use std::os::unix::fs::PermissionsExt;

    let mut permissions = fs::metadata(path)?.permissions();
    permissions.set_mode(0o755);
    fs::set_permissions(path, permissions)?;
    Ok(())
}

#[cfg(not(unix))]
fn make_executable(_path: &Path) -> Result<()> {
    Ok(())
}

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

    use super::{HookInstallMode, HookInstallPlan, pre_push_range_from_line, render_shim};
    use crate::cli::HookName;

    #[test]
    fn hook_shim_is_only_exec_delegation() {
        let shim = render_shim(HookName::CommitMsg, "");
        let lines = shim.lines().collect::<Vec<_>>();

        assert_eq!(lines.len(), 3);
        assert_eq!(lines[0], "#!/bin/sh");
        assert_eq!(lines[1], super::MANAGED_MARKER);
        assert_eq!(
            lines[2],
            "exec truth-mirror hook-dispatch commit-msg \"$@\""
        );
    }

    #[test]
    fn quote_git_arg_escapes_shell_metacharacters() {
        use std::path::Path;
        assert_eq!(super::quote_git_arg(Path::new("/a/b.toml")), "'/a/b.toml'");
        // metacharacters are neutralized by single-quoting
        assert_eq!(
            super::quote_git_arg(Path::new("/a/c;$(touch x).toml")),
            "'/a/c;$(touch x).toml'"
        );
        // an embedded single quote is escaped as '\''
        assert_eq!(
            super::quote_git_arg(Path::new("/a/it's.toml")),
            "'/a/it'\\''s.toml'"
        );
    }

    #[test]
    fn hook_shim_preserves_global_args() {
        let shim = render_shim(HookName::PrePush, "--config /abs/enforce.toml ");
        let lines = shim.lines().collect::<Vec<_>>();

        assert_eq!(lines.len(), 3, "shim stays <=3 lines + exec-only");
        assert_eq!(
            lines[2],
            "exec truth-mirror --config /abs/enforce.toml hook-dispatch pre-push \"$@\""
        );
    }

    #[test]
    fn husky_entire_bridge_is_only_exec_delegation() {
        let bridge = super::render_husky_entire_bridge(HookName::CommitMsg);
        let lines = bridge.lines().collect::<Vec<_>>();

        assert_eq!(lines.len(), 3);
        assert_eq!(lines[0], "#!/bin/sh");
        assert_eq!(lines[1], super::HUSKY_ENTIRE_BRIDGE_MARKER);
        assert_eq!(lines[2], "exec \"$(dirname \"$0\")/commit-msg\" \"$@\"");
    }

    #[test]
    fn dry_run_plan_names_hooks_and_hooks_path() {
        let plan = HookInstallPlan::new(
            std::path::Path::new("/repo"),
            std::path::Path::new("/repo/.truth/hooks"),
            false,
        );
        let rendered = plan.render();

        assert!(rendered.contains("commit-msg"));
        assert!(rendered.contains("post-commit"));
        assert!(rendered.contains("pre-push"));
        assert!(rendered.contains("stateHooks=/repo/.truth/hooks"));
        assert!(rendered.contains("path=/repo/.git/hooks/commit-msg"));
        assert!(rendered.contains("body:\n#!/bin/sh\n# truth-mirror managed hook"));
    }

    #[test]
    fn husky_dry_run_plan_names_entire_bridge_paths() {
        let mut plan = HookInstallPlan::new(
            std::path::Path::new("/repo"),
            std::path::Path::new("/repo/.truth/hooks"),
            false,
        );
        plan.mode = HookInstallMode::Husky {
            content_dir: std::path::PathBuf::from("/repo/.husky"),
        };
        let rendered = plan.render();

        assert!(rendered.contains("bridge=commit-msg.pre-entire"));
        assert!(rendered.contains("path=/repo/.husky/commit-msg.pre-entire"));
        assert!(rendered.contains(super::HUSKY_ENTIRE_BRIDGE_MARKER));
    }

    #[test]
    fn managed_block_replace_is_idempotent() {
        let block = super::render_husky_block(HookName::CommitMsg, "");
        let original = "#!/bin/sh\necho before\n";
        let once = super::append_managed_block(original, &block);
        let twice = super::append_managed_block(&once, &block);

        assert_eq!(twice.matches(super::MANAGED_MARKER).count(), 1);
        assert!(twice.contains("echo before"));
    }

    #[test]
    fn chained_hook_safety_filter_detects_outer_tools() {
        assert!(super::has_outer_hook_marker(
            "#!/bin/sh\n# Entire CLI hooks\nentire hooks git commit-msg\n"
        ));
        assert!(super::has_outer_hook_marker(
            "#!/bin/sh\n# truth-mirror managed hook\nexec truth-mirror hook-dispatch commit-msg \"$@\"\n"
        ));
        assert!(!super::has_outer_hook_marker("#!/bin/sh\necho safe\n"));
    }

    #[test]
    fn run_chained_hook_skips_marker_bearing_stale_hook() {
        let temp = tempfile::tempdir().unwrap();
        let chained = temp.path().join("hooks/chained/commit-msg");
        std::fs::create_dir_all(chained.parent().unwrap()).unwrap();
        std::fs::write(&chained, "#!/bin/sh\n# Entire CLI hooks\nexit 42\n").unwrap();
        super::make_executable(&chained).unwrap();

        super::run_chained_hook(temp.path(), HookName::CommitMsg, &[]).unwrap();
    }

    #[test]
    fn pre_push_line_maps_to_git_range() {
        let line = "refs/heads/main abc123 refs/heads/main def456";

        assert_eq!(
            pre_push_range_from_line(line),
            Some("def456..abc123".to_owned())
        );
    }

    proptest! {
        #[test]
        fn hook_shim_rendering_stays_tiny_exec_only(index in 0usize..3) {
            let hook = [HookName::CommitMsg, HookName::PostCommit, HookName::PrePush][index];
            let shim = render_shim(hook, "");
            let lines = shim.lines().collect::<Vec<_>>();

            prop_assert_eq!(lines.len(), 3);
            prop_assert_eq!(lines[0], "#!/bin/sh");
            prop_assert_eq!(lines[1], super::MANAGED_MARKER);
            prop_assert!(lines[2].starts_with("exec truth-mirror hook-dispatch "));
            prop_assert!(lines[2].contains(hook.as_str()));
            prop_assert_eq!(shim.matches(super::MANAGED_MARKER).count(), 1);
            prop_assert_eq!(shim.matches("exec truth-mirror").count(), 1);
        }

        #[test]
        fn husky_entire_bridge_rendering_stays_tiny_exec_only(index in 0usize..3) {
            let hook = [HookName::CommitMsg, HookName::PostCommit, HookName::PrePush][index];
            let bridge = super::render_husky_entire_bridge(hook);
            let lines = bridge.lines().collect::<Vec<_>>();

            prop_assert_eq!(lines.len(), 3);
            prop_assert_eq!(lines[0], "#!/bin/sh");
            prop_assert_eq!(lines[1], super::HUSKY_ENTIRE_BRIDGE_MARKER);
            prop_assert_eq!(lines[2], format!("exec \"$(dirname \"$0\")/{}\" \"$@\"", hook.as_str()));
            prop_assert_eq!(bridge.matches(super::HUSKY_ENTIRE_BRIDGE_MARKER).count(), 1);
            prop_assert_eq!(bridge.matches("exec ").count(), 1);
        }
    }
}