reference_query/cli/

mod.rs

//! Command-line surface. Search is the default action: `rq <query>`.

use std::collections::HashSet;
use std::io::{IsTerminal, Write};
use std::path::PathBuf;
use std::process::ExitCode;
use std::time::Duration;

use clap::{CommandFactory, Parser};
use clap_complete::Shell;

use crate::store::Store;

/// Search is the default action (`rq <query>`). Operations are flags rather
/// than subcommands so no word is reserved — `rq index`, `rq status`, and
/// `rq record` all search for those symbols. This also matches the rg/fd feel.
#[derive(Parser)]
#[command(
    name = "rq",
    version,
    about = "Ranked definition lookup — the one place a symbol is defined, first.",
    long_about = "rq finds where a symbol is defined and ranks the one you most \
likely meant to the top — not every match.\n\n\
Search is the default action; operations are flags, not subcommands, so every \
word (including \"index\", \"status\", \"record\") stays searchable. Ranking favors \
your current repo and recently-active files, and learns from the results you open \
(see RECORDING below). Run `rq <query> --explain` to see the score behind each result.",
    after_help = "EXAMPLES:\n  \
rq thing                  search for a definition named or like \"thing\"\n  \
rq wibble --explain       same, plus the score behind each result\n  \
rq thing --json           machine-readable results (for editors/agents)\n  \
rq thing --no-record      search without recording it (speculative/agent queries)\n  \
rq thing --no-wait        answer now from the committed index; don't block on a rebuild\n  \
rq thing --wait 2s        ...or wait up to a bounded time for the index to warm\n  \
rq thing app/web          restrict to a directory (rg-style)\n  \
rq perform -k method      restrict to a symbol kind (c/mod/m/f/s/e/t)\n  \
rq class Widget           a leading kind keyword is shorthand for -k\n  \
rq --symbols FILE         outline a file's definitions, in line order\n  \
rq thing -x rust          restrict to a language (ruby/rust/go/python/ts/js)\n  \
rq -o thing               open the best match in your editor (and record it)\n  \
rq --index                index the current repository\n  \
rq --status               show indexing coverage\n  \
rq --usage                show how rq has been called (by caller and flags)\n  \
rq --drop                 remove this repo's index (opposite of --index)\n\n\
SHORT FLAGS (easy to misread):\n  \
-j = --json (not jobs; --jobs is long-only)   -l = --limit (not lang)   -x = --lang\n\n\
RECORDING (editor/shell hook):\n  \
rq --record --file <path> --line <n> <query>\n  \
Tells rq which result you opened for a query, so ranking learns. Pass --no-record \
to a search to skip this. Editors and the script/rq-open wrapper call --record for you.\n\n\
The index is a SQLite file at $RQ_DB (default ~/.local/share/rq/rq.db); it warms \
automatically on the first search in a git repo. On a large, cold repo a search \
keeps indexing until it can answer rather than reporting a premature \"no \
matches\" (an interactive run shows progress and stops on Ctrl-C). Exit codes: 0 \
= matched, 1 = no match, 2 = no match yet (index still warming — try again)."
)]
struct Cli {
    /// Search query. With --drop, the repo path/identity to drop; with --record,
    /// the query the selection was made for.
    //
    // `Other` keeps shells from offering filenames here: a search query isn't a
    // path. The path-valued operations (--index, --symbols) carry their own
    // value with a path hint instead, so completion is scoped to them.
    #[arg(value_name = "TARGET", value_hint = clap::ValueHint::Other)]
    target: Option<String>,

    /// Directories to restrict results to (rg-style; same as repeated --path).
    #[arg(value_name = "PATH")]
    dirs: Vec<String>,

    /// Show the score breakdown for each result.
    #[arg(short = 'e', long)]
    explain: bool,

    /// Don't let this invocation teach ranking or count as usage — suppresses
    /// recording the result you open, select, or `--show`, and keeps the call
    /// out of `--usage`. For benchmark and CI loops, whose repeated queries
    /// would otherwise dominate both.
    #[arg(long)]
    no_record: bool,

    /// Answer immediately from the committed index — never block waiting on a
    /// background (re)index. For agents/scripts: a query issued mid-rebuild
    /// returns at once (a miss reports `warming`, exit 2, so a caller can retry)
    /// instead of blocking up to the wait budget. Shorthand for `--wait 0`;
    /// leftover warming still detaches to a background child.
    #[arg(long = "no-wait")]
    no_wait: bool,

    /// How long a query may wait for the index to warm before answering with
    /// whatever's committed: a duration like `50ms`, `2s`, `1m`, or a bare number
    /// of seconds. `0` doesn't wait at all (same as `--no-wait`). Overrides
    /// `RQ_WAIT_BUDGET_MS` for this call (default 1 minute).
    #[arg(long, value_name = "DUR", value_parser = parse_wait, conflicts_with = "no_wait")]
    wait: Option<Duration>,

    /// Open the best match in your editor and record the pick, so ranking learns.
    /// On a terminal with several matches, prompts to choose. Launcher: `RQ_OPEN`
    /// (a template with `{file}`/`{line}`/`{}` = path:line), else VS Code
    /// (`code`), else `$VISUAL`/`$EDITOR`, else prints the resolved path:line.
    #[arg(short = 'o', long, conflicts_with_all = ["index", "status", "record", "json", "ndjson"])]
    open: bool,

    /// Print the definition's source, not just its location — but only when the
    /// top match is confident; otherwise falls back to the ranked list. Pipe to a
    /// pager (`rq --show foo | less`). JSON adds a `body` field.
    #[arg(long, conflicts_with_all = ["open", "index", "status", "record", "symbols", "drop"])]
    show: bool,

    /// Emit results as a JSON array (for editors and scripts).
    #[arg(short = 'j', long)]
    json: bool,

    /// Emit results as newline-delimited JSON, one object per line.
    #[arg(short = 'J', long, conflicts_with = "json")]
    ndjson: bool,

    /// Restrict results to files under this repo-relative directory (repeatable).
    #[arg(short = 'p', long, value_name = "DIR")]
    path: Vec<String>,

    /// Maximum number of results to show; `0` shows every match.
    #[arg(short = 'l', long, value_name = "N", default_value_t = DEFAULT_LIMIT)]
    limit: usize,

    /// Restrict to symbol kinds: class, module, method, function, struct, enum,
    /// trait (shortcuts: c, mod, m, f, s, e, t; `interface` = trait, `type` =
    /// struct). Repeatable or comma-separated.
    #[arg(short = 'k', long, value_name = "KIND", value_delimiter = ',')]
    kind: Vec<String>,

    /// Restrict to languages: ruby, rust, go, python, typescript, javascript.
    /// Prefix-matched, so `r` means ruby+rust and `p` means python; aliases rb,
    /// rs, golang, ts, tsx, js, jsx. Repeatable or comma-separated.
    #[arg(short = 'x', long = "lang", value_name = "LANG", value_delimiter = ',')]
    lang: Vec<String>,

    /// Search every indexed repository, not just the current one. By default a
    /// search inside a repo returns only that repo's definitions.
    #[arg(short = 'a', long = "all-repos")]
    all_repos: bool,

    /// Index a repository (PATH, or the current directory).
    #[arg(long, value_name = "PATH", num_args = 0..=1, value_hint = clap::ValueHint::AnyPath, conflicts_with_all = ["status", "record"])]
    index: Option<Option<String>>,

    /// Show indexing coverage per known repository.
    #[arg(long, conflicts_with_all = ["index", "record"])]
    status: bool,

    /// Show how rq has been used: searches per day, by caller and flags.
    #[arg(long, conflicts_with_all = ["index", "record", "status"])]
    usage: bool,

    /// List the symbols defined in FILE, in line order — a structural outline,
    /// not a ranked search. Honors -k/-x to filter by kind/language.
    #[arg(long, value_name = "FILE", value_hint = clap::ValueHint::FilePath, conflicts_with_all = ["index", "status", "record", "drop", "open"])]
    symbols: Option<String>,

    /// Drop a repository's index — the opposite of --index. Removes its symbols,
    /// files, coverage, and learned ranking. TARGET is the repo's path (or the
    /// current repo); a known identity string (as shown by --status) also works.
    #[arg(long, conflicts_with_all = ["index", "status", "record", "open"])]
    drop: bool,

    /// Record an interaction (editor/shell hook): the result opened for a query.
    /// Requires --file.
    #[arg(long, requires = "file", conflicts_with_all = ["index", "status"])]
    record: bool,

    /// (--record) File that was opened/selected.
    #[arg(long)]
    file: Option<String>,

    /// (--record) Line landed on (attributes the selection to a definition).
    #[arg(long)]
    line: Option<i64>,

    /// (--record) Event kind (select or open).
    #[arg(long, default_value = "select")]
    event: String,

    /// Finish warming a repository's index in the background — the target a
    /// search re-execs after printing results, detached, so the shell never
    /// waits on it. Single-flighted per repo; safe to run by hand.
    #[arg(long, hide = true, value_name = "PATH", num_args = 0..=1, value_hint = clap::ValueHint::AnyPath, conflicts_with_all = ["index", "status", "record", "drop", "symbols", "open", "show"])]
    warm: Option<Option<String>>,

    /// Print a shell completion script (bash, zsh, fish, elvish, powershell).
    #[arg(long, value_name = "SHELL")]
    completions: Option<Shell>,

    /// Trace what rq decides (root, coverage, warming, reconcile) to stderr —
    /// for debugging. `RQ_LOG=1` does the same for an installed binary.
    #[arg(short = 'v', long)]
    verbose: bool,

    /// Report where a search spent its time, phase by phase, to stderr — as
    /// JSON alongside --json, so a baseline can be stored and diffed.
    /// `RQ_PROFILE=1` does the same for an installed binary.
    #[arg(long)]
    profile: bool,

    /// Parse worker threads the background indexer uses (0 = auto). (`-j` is
    /// taken by `--json`, so this is `--jobs` only.) `RQ_JOBS` works too.
    #[arg(long, value_name = "N", default_value_t = 0)]
    jobs: usize,
}

/// Parse arguments and dispatch. Returns the process exit code.
pub fn run() -> ExitCode {
    let cli = Cli::parse();
    crate::trace::enable_from(cli.verbose);
    crate::profile::enable_from(cli.profile);
    crate::index::set_parse_jobs(cli.jobs);

    if let Some(shell) = cli.completions {
        clap_complete::generate(shell, &mut Cli::command(), "rq", &mut std::io::stdout());
        return ExitCode::SUCCESS;
    }
    if let Some(path) = &cli.index {
        // index PATH (else cwd); with --path, seed only those subtrees
        let out = output_format(&cli);
        return cmd_index(path.as_deref().map(PathBuf::from), &cli.path, out);
    }
    if let Some(path) = &cli.warm {
        return cmd_warm(path.as_deref());
    }
    if cli.status {
        return cmd_status(output_format(&cli));
    }
    if cli.usage {
        return cmd_usage(output_format(&cli));
    }
    if cli.drop {
        let out = output_format(&cli);
        return cmd_drop(cli.target, out);
    }
    if cli.record {
        // a typo'd --event would otherwise record silently and never roll up
        if !matches!(cli.event.as_str(), "select" | "open") {
            return fail(format_args!(
                "rq --record: unknown --event {:?} (expected select or open)",
                cli.event
            ));
        }
        // clap guarantees --file is present via `requires`
        let file = cli.file.expect("--record requires --file");
        return cmd_record(&cli.event, cli.target.as_deref(), &file, cli.line);
    }
    let out = output_format(&cli);
    let mut kinds: Vec<String> = cli.kind.iter().map(|k| canonical_kind(k)).collect();
    // a language token can expand to several tags (`r` → ruby + rust)
    let langs: Vec<String> = cli.lang.iter().flat_map(|x| canonical_langs(x)).collect();
    if let Some(file) = &cli.symbols {
        return cmd_symbols(file, &kinds, &langs, out);
    }
    // path filters: trailing positionals (rg-style) plus any --path flags
    let mut paths = cli.path.clone();
    match cli.target {
        Some(target) => {
            // A leading kind keyword (`rq class Foo`) is shorthand for `-k`; skip
            // it when the user gave an explicit `-k`, so the two never conflict.
            let query = if cli.kind.is_empty() {
                let (kw, query, dirs) = split_kind_keyword(target, cli.dirs.clone());
                if let Some(k) = kw {
                    kinds.push(k.to_string());
                }
                paths.extend(dirs);
                query
            } else {
                paths.extend(cli.dirs.clone());
                target
            };
            let mut session = match Session::open() {
                Ok(s) => s,
                Err(code) => return code,
            };
            cmd_search(
                &mut session,
                &SearchArgs {
                    query: &query,
                    explain: cli.explain,
                    out,
                    paths: &paths,
                    kinds: &kinds,
                    langs: &langs,
                    want: requested_limit(cli.limit),
                    no_record: cli.no_record,
                    no_wait: cli.no_wait,
                    wait: cli.wait,
                    open: cli.open,
                    all_repos: cli.all_repos,
                    show: cli.show,
                    batch: false,
                },
            )
        }
        // No query, but a pipe on stdin: each line is one, all sharing this
        // run's store, repo resolution and warm.
        None if !std::io::stdin().is_terminal() => cmd_batch(&cli, out, &paths, &kinds, &langs),
        // bare `rq` (or just flags like --explain with no query): show help
        None => {
            let _ = Cli::command().print_long_help();
            ExitCode::SUCCESS
        }
    }
}

/// How results are rendered.
#[derive(Clone, Copy, PartialEq)]
enum Output {
    Text,
    Json,
    Ndjson,
}

fn output_format(cli: &Cli) -> Output {
    if cli.ndjson {
        Output::Ndjson
    } else if cli.json {
        Output::Json
    } else {
        Output::Text
    }
}

/// Results shown when `--limit` isn't given.
const DEFAULT_LIMIT: usize = 10;

/// Minimum headroom to rank before a `--path` filter (so filtered-in results
/// aren't lost to the cutoff).
const PATH_HEADROOM: usize = 200;

/// `--limit 0` means unlimited: every ranked hit, bounded only by how many
/// candidates recall returned.
fn requested_limit(limit: usize) -> usize {
    if limit == 0 { usize::MAX } else { limit }
}

/// The call's flags as a canonical, comma-joined string, for usage counts.
/// A fixed vocabulary in a fixed order, so the same call always produces the
/// same string and the counter table stays small — values are never included,
/// only which knobs were reached for.
fn flag_summary(args: &SearchArgs) -> String {
    let mut on: Vec<&str> = Vec::new();
    match args.out {
        Output::Json => on.push("json"),
        Output::Ndjson => on.push("ndjson"),
        Output::Text => {}
    }
    for (present, name) in [
        (args.explain, "explain"),
        (args.show, "show"),
        (args.open, "open"),
        (args.all_repos, "all-repos"),
        (args.no_wait, "no-wait"),
        (args.batch, "batch"),
        (!args.paths.is_empty(), "path"),
        (!args.kinds.is_empty(), "kind"),
        (!args.langs.is_empty(), "lang"),
        (args.want != DEFAULT_LIMIT, "limit"),
    ] {
        if present {
            on.push(name);
        }
    }
    on.join(",")
}

/// How often the search re-checks the index while a cold repo warms on the
/// background thread. Each poll runs a full read query against the DB the
/// indexer is actively writing, so polling too fast steals CPU and read-lock
/// churn from the warm; 100 ms keeps that pressure low while staying
/// imperceptible (an early answer or completion appears within a frame, and the
/// progress line only redraws every `PROGRESS_REDRAW` anyway).
const POLL_INTERVAL: Duration = Duration::from_millis(100);

/// How long a cold-repo query may wait silently before we tell the user we're
/// indexing — short enough to explain the pause, long enough that a repo which
/// indexes quickly never flashes a message.
const HEADS_UP_DELAY: Duration = Duration::from_millis(500);

/// Minimum gap between progress-line redraws once the heads-up is showing — keeps
/// the line from flickering (and the count query off the hot path) while still
/// feeling live.
const PROGRESS_REDRAW: Duration = Duration::from_millis(120);

/// Everything `rq <query>` needs, bundled from the parsed CLI flags.
struct SearchArgs<'a> {
    query: &'a str,
    explain: bool,
    out: Output,
    paths: &'a [String],
    kinds: &'a [String],
    langs: &'a [String],
    /// Number of results to show (`--limit`).
    want: usize,
    no_record: bool,
    /// Answer from the committed index without blocking on a (re)index (`--no-wait`).
    no_wait: bool,
    /// Cap on how long to wait for the index to warm (`--wait`); `None` = the
    /// default/`RQ_WAIT_BUDGET_MS` budget.
    wait: Option<Duration>,
    open: bool,
    all_repos: bool,
    /// One of several queries sharing a run, so each row says which query it
    /// answers — a single stream serving many questions is otherwise
    /// unattributable.
    batch: bool,
    show: bool,
}

/// Default action: search the index and print ranked results.
/// Everything a search needs that doesn't depend on the query: the open store,
/// the repo it's rooted in, the branch's changed files, and who that repo is.
///
/// Split out because it's the expensive half — opening the store, resolving the
/// root, reading branch files, resolving identity — and none of it varies per
/// query. One search builds one and drops it; a caller answering many can build
/// it once. Deliberately *not* holding the warm decision: that one is entangled
/// with the query (the indexer path-prioritises toward it) and belongs to a
/// single search.
struct Session {
    store: Store,
    cwd: Option<PathBuf>,
    cwd_is_git: bool,
    root: Option<PathBuf>,
    active_paths: Vec<String>,
    branch_refresh: Option<BranchRefresh>,
    identity: Option<String>,
    coverage: Option<String>,
}

impl Session {
    /// Resolve the search context, or the exit code to fail with.
    fn open() -> std::result::Result<Session, ExitCode> {
        let open_span = crate::profile::span("store open");
        let store = match open_store() {
            Ok(s) => s,
            Err(e) => return Err(fail(format_args!("rq: cannot open database: {e}"))),
        };
        drop(open_span);
        let git_span = crate::profile::span("setup: git root");
        let cwd = std::env::current_dir().ok();
        let cwd_is_git = cwd.as_deref().is_some_and(crate::index::is_git_repo);

        // Index relative to the repo ROOT, not wherever the search happens to run.
        // Paths and the stored checkout root must be repo-root-relative and stable, or
        // a search from a subdirectory would re-key the same repo under subdir-relative
        // paths — and the deletion reconcile / staleness revalidation would then forget
        // everything indexed from the root. Outside git, the root is just the cwd.
        let root = cwd
            .as_deref()
            .map(|c| crate::index::repo_root(c).unwrap_or_else(|| c.to_path_buf()));
        drop(git_span);

        // Files you're changing on this feature branch (and their directory
        // neighbors): the branch ranking boost, and the warm pass's priority set.
        let mut branch_span = crate::profile::span("setup: branch files");
        let (active_paths, branch_refresh) = match &root {
            Some(c) if cwd_is_git => cached_branch_files(&store, c),
            _ => (Vec::new(), None),
        };
        branch_span.note(|| {
            let how = if branch_refresh.is_some() {
                "cached, refreshing alongside"
            } else {
                "cached"
            };
            format!("{} changed, {how}", active_paths.len())
        });
        drop(branch_span);

        // Resolve identity from the repo root, cache-first: looked up by checkout root
        // (no `git remote` fork), falling back to git only the first time we see a
        // repo. Computed even for non-git dirs so an explicitly `--index`ed one is
        // still recognized as the current repo below.
        let mut identity_span = crate::profile::span("setup: identity");
        let identity = root.as_deref().map(|c| resolve_identity(&store, c));
        let coverage = identity
            .as_deref()
            .and_then(|id| store.coverage_status(id).ok())
            .flatten();
        identity_span.note(|| coverage.as_deref().unwrap_or("unknown").to_string());
        drop(identity_span);
        Ok(Session {
            store,
            cwd,
            cwd_is_git,
            root,
            active_paths,
            branch_refresh,
            identity,
            coverage,
        })
    }
}

/// Answer a stream of queries, one per line on stdin, in a single run.
///
/// Everything a query doesn't vary — the store, the repo, its identity, the
/// branch's changed files — is resolved once and reused, which on a large repo
/// is most of what a single lookup costs. Agents and scripts do runs of
/// lookups; this is that shape.
///
/// A cold repo warms **once, up front, until complete** rather than answering
/// each line from whatever happens to be indexed. Block-until-*answered*
/// doesn't generalise to queries we haven't read yet — you can't prioritise
/// toward them — so block-until-*complete* is the batch-shaped equivalent, and
/// it keeps this file's own rule that correctness beats the first query's
/// latency. `--no-wait` opts out, exactly as it does for one query, and any
/// line the index can't yet answer says so with `status: "warming"`.
fn cmd_batch(
    cli: &Cli,
    out: Output,
    paths: &[String],
    kinds: &[String],
    langs: &[String],
) -> ExitCode {
    if out == Output::Json {
        return fail(format_args!(
            "rq: --json can't frame a stream of queries — use --ndjson (-J), \
             where each line carries the query it answers"
        ));
    }
    if cli.open || cli.show {
        return fail(format_args!(
            "rq: --open and --show act on a single result, not a stream of queries"
        ));
    }

    use std::io::BufRead;
    let queries: Vec<String> = std::io::stdin()
        .lock()
        .lines()
        .map_while(std::result::Result::ok)
        .map(|l| l.trim().to_string())
        .filter(|l| !l.is_empty())
        .collect();
    // Nothing on stdin isn't a batch — it's a bare invocation that happens to
    // run without a terminal (a script, a test harness, stdin from /dev/null).
    // Treat it the way `rq` with no arguments is always treated.
    if queries.is_empty() {
        let _ = Cli::command().print_long_help();
        return ExitCode::SUCCESS;
    }

    let mut session = match Session::open() {
        Ok(s) => s,
        Err(code) => return code,
    };

    // Warm to completion before answering anything, so a cold repo doesn't
    // return a page of misses that only mean "not indexed yet".
    if !cli.no_wait
        && session.coverage.as_deref() != Some("complete")
        && let Some(root) = session.root.clone()
    {
        {
            let budget = cli.wait.unwrap_or_else(wait_budget);
            crate::trace!(
                "batch: warming {} queries' worth of index first",
                queries.len()
            );
            let active = session.active_paths.clone();
            let _ = crate::index::index_budgeted(&mut session.store, &root, &active, budget, None);
            session.coverage = session
                .identity
                .as_deref()
                .and_then(|id| session.store.coverage_status(id).ok())
                .flatten();
        }
    }

    let mut worst = ExitCode::SUCCESS;
    let mut any_hit = false;
    for query in &queries {
        let code = cmd_search(
            &mut session,
            &SearchArgs {
                query,
                explain: cli.explain,
                out,
                paths,
                kinds,
                langs,
                want: requested_limit(cli.limit),
                no_record: cli.no_record,
                // The warm happened above, once. Per-query warming would undo
                // the point of batching, and block-until-answered is meaningless
                // when the queries were all read up front.
                no_wait: true,
                wait: cli.wait,
                open: false,
                all_repos: cli.all_repos,
                show: false,
                batch: true,
            },
        );
        if code == ExitCode::SUCCESS {
            any_hit = true;
        } else {
            worst = code;
        }
    }
    // The batch ran; per-line `status` carries each query's outcome. Only a
    // wholly fruitless batch reports failure, mirroring one query's contract.
    if any_hit { ExitCode::SUCCESS } else { worst }
}

fn cmd_search(session: &mut Session, args: &SearchArgs) -> ExitCode {
    let &SearchArgs {
        query,
        out,
        want,
        no_record,
        no_wait,
        wait,
        open,
        all_repos,
        show,
        ..
    } = args;
    // `--wait DUR` overrides the wait budget for this call; `--wait 0` (or
    // `--no-wait`) means don't block or warm in-process at all.
    let wait_budget = wait.unwrap_or_else(wait_budget);
    let no_wait = no_wait || wait_budget.is_zero();
    // post-filters (--path, --kind, --lang) need headroom before the cutoff so a
    // filtered-in result isn't lost to the top-N truncation
    let limit = if args.paths.is_empty() && args.kinds.is_empty() && args.langs.is_empty() {
        want
    } else {
        want.saturating_mul(20).max(PATH_HEADROOM)
    };
    let _timer = crate::trace::Timer::start("search done");
    let profile_started = std::time::Instant::now();
    let t_setup = std::time::Instant::now();
    // Brackets the warm decision as well as the session, so it outlives both.
    let setup_span = crate::profile::span("setup");
    // Borrowed field-by-field so the body reads the same as when it owned them,
    // while the session itself outlives this call and can answer again.
    let Session {
        store,
        cwd,
        cwd_is_git,
        root,
        active_paths,
        branch_refresh,
        identity,
        coverage,
    } = session;
    let cwd_is_git = *cwd_is_git;

    // Opportunistic indexing (Layer 5), time-bounded so the first query in a
    // large repo never blocks on a full walk. We may warm a git work tree (safe
    // to auto-discover) *or* any dir we already track — one earns tracking by
    // being explicitly `--index`ed, which opts a non-git dir in. We never warm
    // an unknown non-git dir (don't walk a random directory). A subtree index
    // (`--index --path …`) is a seed, not a fence: coverage stays `warming`, so
    // warming continues over the rest of the repo from here.
    let known = coverage.is_some();
    let warming_ok = cwd_is_git || known;
    if crate::trace::enabled() {
        crate::trace!(
            "query {query:?}: root={} identity={} coverage={} warming_ok={warming_ok} active={}",
            root.as_deref().map_or("?".into(), crate::trace::abbrev),
            identity.as_deref().unwrap_or("none"),
            coverage.as_deref().unwrap_or("none"),
            active_paths.len(),
        );
    }
    let repo_span = crate::profile::span("setup: repo state");
    let current = identity
        .as_deref()
        .and_then(|id| store.repository_id(id).ok().flatten());
    // Default: scope results to the current repo (when it's indexed) so a search
    // never leaks another repo's definitions. `--all-repos` searches everything.
    let only_repo = if all_repos { None } else { current };
    let active = crate::search::ActiveFiles::new(active_paths.clone());

    drop(repo_span);
    let warm_span = crate::profile::span("setup: warm decision");

    // Warm the index on a background thread (its own connection — WAL lets it
    // write while we read) whenever there's work: a not-yet-complete repo, or a
    // complete one changed since it was indexed. The search below reads whatever
    // it has committed so far. With detach on (the default), this in-process
    // warm only serves *this* answer — leftover work goes to a detached child
    // after results print, so the shell never waits on it.
    let warm_budget = if warm_detach_enabled() {
        answer_warm_budget()
    } else {
        answer_warm_budget() + deferred_warm_budget()
    };
    let was_warming = coverage.as_deref() != Some("complete");

    // On a complete repo the only question left is whether the worktree moved
    // since it was indexed — and answering it forks `git status`, which on a
    // large worktree is most of a query's cost. It decides nothing this answer
    // depends on: with `was_warming` false, `block` and `polling` below are
    // false too, the search reads the committed index, and `revalidate_top`
    // guarantees the freshness of what we print. So start it alongside the
    // search and collect it in `settle_warm` once results are out.
    //
    // A still-warming repo never ran this check at all — the `||` short-circuit
    // saw to that — so its path here is unchanged.
    let indexed_head = (!was_warming)
        .then(|| current.and_then(|id| store.indexed_head(id).ok().flatten()))
        .flatten();
    // Whether the worktree moved is a property of the repo, not of the query,
    // so a batch asks once (up front) instead of forking `git status` per line.
    let staleness = (!was_warming && warming_ok && !args.batch)
        .then(|| root.clone())
        .flatten()
        .map(|c| std::thread::spawn(move || worktree_changed(&c, indexed_head.as_deref())));
    // Only a repo that's still warming warms *before* the answer now; a
    // complete-but-edited one is reindexed by `settle_warm` afterwards.
    let want_warm = warming_ok && was_warming && root.is_some();

    // Block-until-answered on a cold/partial repo. A bounded warm exists so a
    // query never hangs, but on a *huge, cold* repo it can expire before the
    // symbol is indexed — turning a real hit into a false "no matches". Since
    // correctness beats the first query's latency (and once warm the repo answers
    // fast), we keep indexing until the answer appears or the repo is fully
    // indexed — for humans *and* programs alike. Small/medium repos finish inside
    // the normal budget and are unaffected; only a genuinely large cold repo
    // waits, and only once.
    // `--no-wait`: a scripted/agent caller that would rather answer from the
    // committed index right now than block up to the wait budget while a
    // background rebuild rewrites the index. It suppresses the block-until-answered
    // escalation *and* the in-process warm (no lock contention, no join) — leftover
    // warming still detaches below, so the index keeps improving for next time.
    let block = want_warm && was_warming && !no_wait;
    // A human at a plain-text terminal also gets a live progress heads-up and a
    // graceful Ctrl-C; piped/`--json` callers (agents, scripts) block silently and
    // are bounded by a wait budget instead, since there's nothing to draw to and
    // no one to interrupt.
    let progress_ui = block && show_progress(out, stderr_interactive());
    let indexer_budget = if block { wait_budget } else { warm_budget };
    if progress_ui {
        install_interrupt_handler();
    }

    // `warm_done` lets the poll stop the instant the indexer finishes — so a miss
    // on a small repo returns as soon as it's indexed, not at the deadline.
    let warm_done = std::sync::Arc::new(std::sync::atomic::AtomicBool::new(false));
    let indexer = (want_warm && root.is_some() && !no_wait).then(|| {
        crate::trace!(
            "background warm ({indexer_budget:?}, block={block}, progress_ui={progress_ui}, {} jobs)",
            crate::index::parse_jobs()
        );
        let root = root.clone().expect("checked");
        let active = active_paths.clone();
        let q = query.to_string();
        let warm_done = std::sync::Arc::clone(&warm_done);
        std::thread::spawn(move || {
            if let Ok(mut idx) = open_store() {
                // path-prioritize toward the query so the relevant file indexes first
                let _ = if block {
                    // the abort flag (`INTERRUPTED`) lets a Ctrl-C, a wait timeout,
                    // or an early answer stop the pass without losing committed work
                    crate::index::index_budgeted_cancellable(
                        &mut idx,
                        &root,
                        &active,
                        indexer_budget,
                        Some(&q),
                        &INTERRUPTED,
                    )
                } else {
                    crate::index::index_budgeted(&mut idx, &root, &active, indexer_budget, Some(&q))
                };
            }
            warm_done.store(true, std::sync::atomic::Ordering::Relaxed);
        })
    });

    // Poll while a cold/partial repo warms. Don't print the first hit off a sparse
    // index — a fuzzy or path match can be wrong once more is indexed. Hold until a
    // *high-confidence* (exact or prefix name) match appears; otherwise keep
    // building until the index is complete (a "no matches" is then trustworthy), a
    // wait deadline passes, or — interactively — Ctrl-C. A human sees a progress
    // line once the pause is noticeable.
    crate::trace!(
        "setup (open + repo detect + warm decision): {} ms",
        t_setup.elapsed().as_millis()
    );
    let poll_start = std::time::Instant::now();
    // Deadline: an interactive block waits unbounded (Ctrl-C escapes); a
    // programmatic block waits out the wait budget; a non-block (complete repo)
    // keeps the original fast answer budget.
    let deadline = if progress_ui {
        None
    } else if block {
        Some(poll_start + wait_budget)
    } else {
        Some(poll_start + answer_warm_budget())
    };
    drop(warm_span);
    let polling = indexer.is_some() && was_warming;
    // Everything before the first search: resolving the repo root, checking
    // coverage, deciding whether to warm. It runs on every query, so it counts
    // toward the first-answer budget even though no searching happened yet.
    drop(setup_span);
    let mut query_span = crate::profile::span("query");
    let label = repo_label(root.as_deref());
    let mut drew_progress = false;
    let mut last_draw = poll_start;
    let mut hits = loop {
        match crate::search::search(store, query, current, only_repo, &active, limit) {
            Ok(h) => {
                let confident = h.first().is_some_and(|hit| {
                    hit.features
                        .iter()
                        .any(|f| matches!(f.name, "exact" | "prefix"))
                });
                let warm_finished = warm_done.load(std::sync::atomic::Ordering::Relaxed);
                let stopped = INTERRUPTED.load(std::sync::atomic::Ordering::Relaxed);
                let timed_out = deadline.is_some_and(|d| std::time::Instant::now() >= d);
                if !polling || confident || warm_finished || stopped || timed_out {
                    break h;
                }
                if progress_ui
                    && poll_start.elapsed() >= HEADS_UP_DELAY
                    && last_draw.elapsed() >= PROGRESS_REDRAW
                {
                    draw_progress(store, identity.as_deref(), &label);
                    drew_progress = true;
                    last_draw = std::time::Instant::now();
                }
            }
            Err(e) => {
                if let Some(h) = indexer {
                    let _ = h.join();
                }
                return fail(format_args!("rq: {e}"));
            }
        }
        std::thread::sleep(POLL_INTERVAL);
    };
    query_span.note(|| {
        if polling {
            "polled a warming index".to_string()
        } else {
            String::new()
        }
    });
    drop(query_span);
    if drew_progress {
        clear_progress();
    }
    // Captured before we self-cancel below, so it reflects only a *user's* Ctrl-C.
    let interrupted = INTERRUPTED.load(std::sync::atomic::Ordering::Relaxed);

    // Staleness: revalidate the files behind the top hits; re-rank once if changed.
    if !hits.is_empty() && revalidate_top(store, &hits) {
        hits = crate::search::search(store, query, current, only_repo, &active, limit)
            .unwrap_or_default();
    }

    // Untracked non-git dir — nothing persisted, no warmer running — so scan it
    // live in-memory (substring, then fuzzy) and blend with whatever the index
    // gave. The only non-persisting scan left.
    if !hits.iter().any(strong)
        && indexer.is_none()
        && coverage.is_none()
        && let Some(root) = &root
    {
        let tail = live_fallback(root, query, limit);
        hits = crate::search::merge(hits, tail, limit);
    }

    apply_gates(query, &mut hits);
    apply_post_filters(args, cwd.as_deref(), root.as_deref(), &mut hits);

    // Count the query here, above the miss return, so one call site covers
    // every exit below (miss, --show, --open, the ranked list). Observability
    // only: `search` rows are invisible to the rollup that feeds ranking.
    if !no_record {
        let _ = store.record_search(
            &query.to_ascii_lowercase(),
            current,
            hits.len(),
            &crate::origin::detect(),
            &flag_summary(args),
        );
    }

    if hits.is_empty() {
        // Stop a still-running block so the join is prompt, then settle coverage.
        if block {
            INTERRUPTED.store(true, std::sync::atomic::Ordering::Relaxed);
        }
        if let Some(h) = indexer {
            let _ = h.join();
        }
        // A miss against a *complete* index is definitive (the symbol isn't
        // there); against a still-warming one it's only "not yet". Distinguish
        // them so a caller — agent or script — isn't misled into thinking the
        // symbol is absent when the index simply hasn't reached it. `--no-wait`
        // returns without blocking, so its miss is judged the same way — an
        // incomplete index yields `warming` (exit 2, "retry"), not a false absence.
        let mut incomplete = (block || no_wait)
            && identity
                .as_deref()
                .and_then(|id| store.coverage_status(id).ok().flatten())
                .as_deref()
                != Some("complete");
        // a "not yet" miss leaves work behind — reindex an edited worktree and
        // let a detached child keep warming, so the retry lands on a better
        // index. This is the path a just-added symbol takes, so it has to do
        // the same settling the render path does.
        // A worktree that has moved since we indexed it makes this miss
        // provisional, not definitive: the symbol may be in an edit the
        // detached warm hasn't caught up with. Say "warming" (exit 2, retry)
        // rather than "no match" (exit 1, absent) — a just-added symbol is
        // exactly this case, and a confident no is the wrong answer to it.
        incomplete |= settle_warm(
            store,
            staleness,
            was_warming,
            warming_ok,
            root.as_deref(),
            active_paths,
            query,
            warm_budget,
            no_wait,
            identity.as_deref(),
        );
        return no_match_code(out, query, interrupted, incomplete);
    }

    // Attach each result's definition line (e.g. `def perform(refund)`) — shown
    // in text output and carried in JSON. Cheap: only the displayed results.
    for hit in &mut hits {
        hit.signature = read_signature(
            store,
            &hit.repo_identity,
            &hit.file,
            hit.line,
            cwd.as_deref(),
        );
    }
    attach_confidence(&mut hits);

    // --show: print the top hit's full source when confident; otherwise fall
    // through to the normal ranked list (rq won't dump a body it isn't sure of).
    if show
        && let Some(code) = show_top_definition(
            store,
            &mut hits,
            query,
            out,
            cwd.as_deref(),
            current,
            no_record,
        )
    {
        return code;
    }

    // --open: pick the best match (prompting on a TTY with several), record the
    // pick so ranking learns, and hand off to the editor. Returns before the
    // normal print / warm-join — opening should be snappy, and a launcher `exec`s.
    if open {
        return finish_open(store, &hits, query, current, root.as_deref(), no_record);
    }

    if let Some(code) = render_hits(args, &hits) {
        return code;
    }

    // Report before the deferred maintenance below, so the total covers
    // getting answers out rather than the bookkeeping that follows them.
    if crate::profile::enabled() {
        let total = profile_started.elapsed();
        if args.out == Output::Text {
            for line in crate::profile::report(total) {
                eprintln!("{line}");
            }
        } else {
            // stdout stays exactly the results, so the profile can be captured
            // separately and diffed.
            eprintln!("{}", crate::profile::json(total));
        }
    }

    // Collect the refresh started back at setup. It ran alongside the search
    // rather than after it, so by now it has usually finished — and it only
    // ever feeds the *next* query, never this one's ranking, so waiting on it
    // can't reorder what was just printed.
    // Taken, not borrowed: the refresh is one-shot, and a session answering
    // several queries must not re-store a result it already consumed.
    if let Some(refresh) = branch_refresh.take() {
        refresh.store(store);
    }

    // Results are out — now the cheap deferred work, amortized across
    // interactions: roll the `open`/`select` picks that teach ranking into
    // `selection_stats`, and prune the raw log. The `search` row written above
    // is skipped by the rollup — it counts usage, it doesn't teach.
    deferred_maintenance(store);

    // Results are out; stop the in-process warm (it persists as it goes, so a
    // cut pass keeps everything parsed) and join it — then hand whatever's left
    // to a detached child, which finishes coverage with a budget no foreground
    // query could afford. The shell only ever waits on the answer.
    if block {
        INTERRUPTED.store(true, std::sync::atomic::Ordering::Relaxed);
    }
    if let Some(h) = indexer {
        let _ = h.join();
    }
    let _ = settle_warm(
        store,
        staleness,
        was_warming,
        warming_ok,
        root.as_deref(),
        active_paths,
        query,
        warm_budget,
        no_wait,
        identity.as_deref(),
    );

    ExitCode::SUCCESS
}

/// Re-exec a detached warm child when this query's warming didn't finish the
/// job. No-op when detach is off, nothing was warming, or coverage completed.
fn maybe_detach_warm(
    store: &Store,
    want_warm: bool,
    changed: bool,
    root: Option<&std::path::Path>,
    identity: Option<&str>,
) {
    if !warm_detach_enabled() || !want_warm {
        return;
    }
    let (Some(root), Some(id)) = (root, identity) else {
        return;
    };
    // Coverage measures breadth, not freshness — an edit never demotes it. So
    // "complete" alone isn't done; it's done only if the worktree also hasn't
    // moved since we indexed it.
    if !changed && store.coverage_status(id).ok().flatten().as_deref() == Some("complete") {
        return; // the in-process pass finished the job
    }
    spawn_detached_warm(root);
}

/// Spawn `rq --warm <root>` fully detached: null stdio and its own process
/// group, so it survives this process and a later Ctrl-C in the terminal
/// can't reach it. The child nices itself and is single-flighted per repo.
fn spawn_detached_warm(root: &std::path::Path) {
    use std::os::unix::process::CommandExt;
    let Ok(exe) = std::env::current_exe() else {
        return;
    };
    let mut cmd = std::process::Command::new(exe);
    cmd.arg("--warm")
        .arg(root)
        .stdin(std::process::Stdio::null())
        .stdout(std::process::Stdio::null())
        .stderr(std::process::Stdio::null())
        .process_group(0);
    match cmd.spawn() {
        Ok(child) => crate::trace!(
            "background warm (detached): pid {} for {}",
            child.id(),
            crate::trace::abbrev(root)
        ),
        Err(e) => crate::trace!("detached warm failed to spawn: {e}"),
    }
}

/// How long a warm lock is trusted without a liveness hit — past this, a
/// stamp is a crashed warmer's leftover and a new child takes over.
const WARM_LOCK_TTL_SECS: i64 = 600;

/// `rq --warm [PATH]`: the detached child a search re-execs after printing —
/// finishes warming the repo's index in the background. Niced so it stays out
/// of the foreground's way; single-flighted per repo so a burst of queries
/// runs at most one warmer. Safe (and boring) to run by hand.
fn cmd_warm(path: Option<&str>) -> ExitCode {
    // Stay out of the way: drop scheduling priority, and throttle disk I/O on
    // macOS. Best-effort — a failure just means a less-polite warm.
    #[cfg(target_os = "macos")]
    unsafe extern "C" {
        // <sys/resource.h>; not in the libc crate. Args below:
        // IOPOL_TYPE_DISK=0, IOPOL_SCOPE_PROCESS=0, IOPOL_THROTTLE=3.
        fn setiopolicy_np(
            iotype: libc::c_int,
            scope: libc::c_int,
            policy: libc::c_int,
        ) -> libc::c_int;
    }
    unsafe {
        libc::nice(10);
        #[cfg(target_os = "macos")]
        setiopolicy_np(0, 0, 3);
    }
    let mut store = match open_store() {
        Ok(s) => s,
        Err(_) => return ExitCode::FAILURE,
    };
    let start = path
        .map(PathBuf::from)
        .or_else(|| std::env::current_dir().ok())
        .unwrap_or_else(|| PathBuf::from("."));
    let root = crate::index::repo_root(&start).unwrap_or(start);
    let identity = resolve_identity(&store, &root);

    // Single-flight: if another live rq is already warming this repo, bow out.
    // A dead pid or a stale stamp is a crashed warmer — take over.
    if let Ok(Some((pid, ts))) = store.warm_lock(&identity)
        && pid != std::process::id()
        && unsafe { libc::kill(pid as libc::pid_t, 0) } == 0
        && now_secs() - ts < WARM_LOCK_TTL_SECS
    {
        return ExitCode::SUCCESS;
    }
    let _ = store.set_warm_lock(&identity, std::process::id());

    // Sweep until coverage completes, the budget runs out, or a pass stops
    // making progress (each pass converges — mtime-skips what's done).
    let deadline = std::time::Instant::now() + warm_bg_budget();
    let active = crate::index::branch_changed_files(&root);
    loop {
        let remaining = deadline.saturating_duration_since(std::time::Instant::now());
        if remaining.is_zero() {
            break;
        }
        let stats = match crate::index::index_budgeted(&mut store, &root, &active, remaining, None)
        {
            Ok(s) => s,
            Err(_) => break,
        };
        if store.coverage_status(&identity).ok().flatten().as_deref() == Some("complete")
            || stats.files_indexed == 0
        {
            break;
        }
    }
    let _ = store.clear_warm_lock(&identity);
    ExitCode::SUCCESS
}

fn now_secs() -> i64 {
    std::time::SystemTime::now()
        .duration_since(std::time::UNIX_EPOCH)
        .map(|d| d.as_secs() as i64)
        .unwrap_or(0)
}

/// Live in-memory scan of an untracked (non-git, never-indexed) dir: substring
/// pre-filtered first, then the unfiltered fuzzy retry. Persists nothing.
fn live_fallback(root: &std::path::Path, query: &str, limit: usize) -> Vec<crate::search::Hit> {
    crate::trace!("empty → live (in-memory) scan of an untracked dir");
    let deadline = std::time::Instant::now() + live_fallback_budget();
    let h = crate::search::live_search(root, query, limit, &HashSet::new(), Some(deadline), true);
    if !h.is_empty() {
        return h;
    }
    crate::search::live_search(root, query, limit, &HashSet::new(), Some(deadline), false)
}

/// A high-confidence name match: exact or prefix (not fuzzy/path-only).
fn strong(h: &crate::search::Hit) -> bool {
    h.features
        .iter()
        .any(|f| matches!(f.name, "exact" | "prefix"))
}

/// The result-quality gates, in order:
/// - relevance: when the query lands a real name match (exact or prefix), drop
///   the scattered fuzzy / path-only near-matches — they're noise next to a
///   solid hit, and rq favors fewer, better results. A purely-fuzzy query (no
///   exact/prefix anywhere) keeps its matches.
/// - scope: a qualified query (`Foo::Bar#baz`) that lands inside the named
///   scope keeps only the in-scope results; if none match, the others stay
///   (the definition may live elsewhere).
fn apply_gates(query: &str, hits: &mut Vec<crate::search::Hit>) {
    if hits.iter().any(strong) {
        hits.retain(strong);
    }
    crate::search::apply_scope_gate(query, hits);
}

/// Post-filters: keep only results under a `--path` dir, of a `--kind`, and/or
/// in a `--lang`, then trim to the requested count.
fn apply_post_filters(
    args: &SearchArgs,
    cwd: Option<&std::path::Path>,
    root: Option<&std::path::Path>,
    hits: &mut Vec<crate::search::Hit>,
) {
    if !args.paths.is_empty() {
        // --path values may be absolute or cwd-relative; stored files are
        // repo-root-relative, so normalize before prefix-matching or an
        // absolute path would silently filter everything out.
        let here = cwd.map_or_else(|| PathBuf::from("."), PathBuf::from);
        let base = root.map_or_else(|| here.clone(), PathBuf::from);
        let norm: Vec<String> = args
            .paths
            .iter()
            .map(|p| repo_relative(&base, &here, p))
            .collect();
        hits.retain(|h| under_any(&h.file, &norm));
    }
    if !args.kinds.is_empty() {
        hits.retain(|h| args.kinds.iter().any(|k| k == &h.kind));
    }
    if !args.langs.is_empty() {
        hits.retain(|h| args.langs.iter().any(|l| l == &h.language));
    }
    if !args.paths.is_empty() || !args.kinds.is_empty() || !args.langs.is_empty() {
        hits.truncate(args.want);
    }
}

/// Report a miss and pick its exit code. Structured callers get a reason, not
/// a bare `[]`/empty: `warming` (retry — index incomplete), `interrupted` (a
/// stopped block), or `no_match` (definitive). Text keeps its human message.
/// Exit 2 = indeterminate (index incomplete), 1 = a definitive miss — both
/// non-zero, so `rq … && …` still reads as "found something".
fn no_match_code(out: Output, query: &str, interrupted: bool, incomplete: bool) -> ExitCode {
    let status = if interrupted {
        "interrupted"
    } else if incomplete {
        "warming"
    } else {
        "no_match"
    };
    match out {
        Output::Json | Output::Ndjson => {
            let obj = serde_json::json!({ "status": status, "query": query });
            let _ = emit_json(out, &obj); // the exit code below carries the miss
        }
        Output::Text if interrupted => {
            eprintln!("rq: indexing interrupted — run again to finish")
        }
        Output::Text if incomplete => eprintln!(
            "rq: still indexing — no match for {query:?} yet (run again, or `rq --index` to finish)"
        ),
        Output::Text => eprintln!("no matches for {query:?}"),
    }
    if incomplete {
        ExitCode::from(2)
    } else {
        ExitCode::FAILURE
    }
}

/// Normalized confidence per hit: match quality scaled by dominance over the
/// other results (needs the whole ranked set). "Best other" is the top score —
/// or the runner-up, for the top hit itself.
fn attach_confidence(hits: &mut [crate::search::Hit]) {
    let (top, second) = hits.iter().fold((None::<f64>, None::<f64>), |(t, s), h| {
        if t.is_none_or(|t| h.score > t) {
            (Some(h.score), t)
        } else if s.is_none_or(|s| h.score > s) {
            (t, Some(h.score))
        } else {
            (t, s)
        }
    });
    for hit in hits.iter_mut() {
        let best_other = if Some(hit.score) == top { second } else { top };
        hit.confidence = crate::search::confidence(
            hit.score,
            crate::search::match_quality(&hit.features),
            best_other,
        );
    }
}

/// Print the ranked results (JSON array, NDJSON lines, or highlighted text).
/// `Some(exit)` on a serialization failure, `None` on success.
fn render_hits(args: &SearchArgs, hits: &[crate::search::Hit]) -> Option<ExitCode> {
    // Time to the first printed result, not to the last: rq streams, and the
    // sub-50 ms budget is about the first answer. A change that speeds the
    // total while delaying this one is a regression.
    let render_span = crate::profile::span("render");
    if args.batch {
        // One stream, many questions: tag each row with the query it answers,
        // the same way `no_match_code` already tags a miss.
        #[derive(serde::Serialize)]
        struct Tagged<'a> {
            query: &'a str,
            #[serde(flatten)]
            hit: &'a crate::search::Hit,
        }
        let rows: Vec<Tagged> = hits
            .iter()
            .map(|hit| Tagged {
                query: args.query,
                hit,
            })
            .collect();
        if let Some(code) = emit_rows(args.out, &rows) {
            return Some(code);
        }
    } else if let Some(code) = emit_rows(args.out, hits) {
        return Some(code);
    }
    if args.out != Output::Text {
        return None;
    }
    drop(render_span);
    let color = match_color();
    let c = color.as_deref();
    let query = args.query;
    if args.show {
        // fell through from --show: no single confident match to print
        eprintln!(
            "rq: no single confident match for {query:?} — {} candidates below; narrow the query to --show one",
            hits.len()
        );
    }
    for hit in hits {
        // highlight the chars the query matched — in the name, the
        // filename, and the definition line (great for fuzzy matches)
        let name = hl(&hit.name, query, c);
        let qualified = match &hit.parent {
            Some(p) => format!("{name} · {p}"),
            None => name,
        };
        println!(
            "{}:{}  {} {}",
            hl_path(&hit.file, query, c),
            hit.line,
            hit.kind,
            qualified
        );
        if let Some(sig) = &hit.signature {
            println!("    {}", hl(sig, query, c));
        }
        if args.explain {
            let parts: Vec<String> = hit
                .features
                .iter()
                .map(|f| format!("{} {:.0}", f.name, f.value))
                .collect();
            println!(
                "    confidence {:.2} · score {:.0} = {}",
                hit.confidence,
                hit.score,
                parts.join(" + ")
            );
        }
    }
    None
}

/// Pick a hit for `--open`: the top match, unless we're on an interactive
/// terminal with several — then print a short numbered menu and read a choice
/// (empty = the top match). `None` means abort (EOF or unparseable input).
fn choose_hit(hits: &[crate::search::Hit]) -> Option<&crate::search::Hit> {
    use std::io::{IsTerminal, Write};
    if hits.len() == 1 || !std::io::stdin().is_terminal() || !std::io::stderr().is_terminal() {
        return hits.first();
    }
    let mut err = std::io::stderr();
    let _ = writeln!(err, "rq: {} matches — pick one (enter = 1):", hits.len());
    for (i, h) in hits.iter().enumerate() {
        let _ = writeln!(
            err,
            "  {}. {}:{}  {} {}",
            i + 1,
            h.file,
            h.line,
            h.kind,
            h.name
        );
    }
    let _ = write!(err, "rq> ");
    let _ = err.flush();
    let mut line = String::new();
    if std::io::stdin().read_line(&mut line).unwrap_or(0) == 0 {
        return None; // Ctrl-D
    }
    parse_choice(&line, hits.len()).and_then(|i| hits.get(i))
}

/// Resolve a menu reply to a 0-based index: blank → 0 (the top match), `N` → N-1
/// when in range, anything else → `None` (abort). Pure, so it's unit-tested.
fn parse_choice(input: &str, n: usize) -> Option<usize> {
    let s = input.trim();
    if s.is_empty() {
        return Some(0);
    }
    let i = s.parse::<usize>().ok()?.checked_sub(1)?;
    (i < n).then_some(i)
}

/// `--open`: choose a hit, record it as a selection so ranking learns, then hand
/// off to the editor. The launcher `exec`s (replacing this process), so the shell
/// waits on the editor — not on rq's background warm.
fn finish_open(
    store: &mut Store,
    hits: &[crate::search::Hit],
    query: &str,
    current: Option<i64>,
    root: Option<&std::path::Path>,
    no_record: bool,
) -> ExitCode {
    let Some(hit) = choose_hit(hits) else {
        return ExitCode::SUCCESS; // aborted at the prompt
    };

    // Record the pick — same signal as `rq --record`. The hit's path is already
    // repo-relative, which is what the selection rollup keys off.
    if !no_record {
        let _ = store.record_event(
            "select",
            Some(&query.to_ascii_lowercase()),
            current,
            Some(&hit.file),
            Some(hit.line),
            None,
        );
        deferred_maintenance(store);
    }

    // Results are repo-root-relative, so resolve against the root — the bare path
    // wouldn't open from a subdirectory.
    let target = match root {
        Some(r) => r.join(&hit.file),
        None => PathBuf::from(&hit.file),
    };
    launch_editor(&target, hit.line)
}

/// Launch the editor on `file:line`, resolving the command in order: `RQ_OPEN`
/// template → VS Code (`code`) → `$VISUAL`/`$EDITOR` → print the location. The
/// chosen command replaces this process via `exec`.
fn launch_editor(file: &std::path::Path, line: i64) -> ExitCode {
    use std::os::unix::process::CommandExt;
    let loc = format!("{}:{}", file.display(), line);
    match open_command(file, line, &loc) {
        Some((prog, args)) => {
            // exec returns only on failure
            let err = std::process::Command::new(&prog).args(&args).exec();
            fail(format_args!("rq --open: cannot run {prog}: {err}"))
        }
        None => {
            println!("{loc}");
            ExitCode::SUCCESS
        }
    }
}

/// Resolve the editor command + args. `None` → no launcher configured (the
/// caller prints the location). `RQ_OPEN` is split on whitespace (no shell) with
/// `{file}` / `{line}` / `{}` (= `path:line`) substituted per token.
fn open_command(file: &std::path::Path, line: i64, loc: &str) -> Option<(String, Vec<String>)> {
    let fstr = file.to_string_lossy().into_owned();

    if let Some(t) = std::env::var_os("RQ_OPEN") {
        let t = t.to_string_lossy();
        let mut parts = t.split_whitespace().map(|p| {
            p.replace("{file}", &fstr)
                .replace("{line}", &line.to_string())
                .replace("{}", loc)
        });
        if let Some(prog) = parts.next() {
            return Some((prog, parts.collect()));
        }
    }

    if on_path("code") {
        return Some(("code".into(), vec!["--goto".into(), loc.into()]));
    }

    if let Some(ed) = std::env::var_os("VISUAL").or_else(|| std::env::var_os("EDITOR")) {
        let ed = ed.to_string_lossy().into_owned();
        let l = ed.to_ascii_lowercase();
        // line-aware launch for the common terminal editors; others just get the file
        if ["vim", "nvim", "vi", "nano", "emacs", "kak", "micro"]
            .iter()
            .any(|e| l.contains(e))
        {
            return Some((ed, vec![format!("+{line}"), fstr]));
        }
        return Some((ed, vec![fstr]));
    }

    None
}

/// Whether `prog` resolves on `PATH` (a regular file; symlinks followed).
fn on_path(prog: &str) -> bool {
    std::env::var_os("PATH")
        .is_some_and(|paths| std::env::split_paths(&paths).any(|dir| dir.join(prog).is_file()))
}

/// Whether a complete repo is provably unchanged since its last index — same
/// HEAD and a clean work tree — so the deferred re-walk can be skipped. The git
/// HEAD + dirty check is cheap (~tens of ms) and authoritative at any size, so
/// it gates warming for small and large repos alike: a clean, fully-indexed repo
/// has nothing to warm, and re-walking it on every query just to discover that
/// wasted a full sweep (~hundreds of ms) per search. Conservative: any
/// uncertainty (not complete, non-git / no recorded head, git hiccup) returns
/// false, so we warm.
/// Seconds since the epoch.
fn unix_now() -> i64 {
    std::time::SystemTime::now()
        .duration_since(std::time::UNIX_EPOCH)
        .map(|d| d.as_secs() as i64)
        .unwrap_or(0)
}

/// How long a branch-file list is served before it's refreshed. A commit or a
/// checkout is caught by the stamp; a bare working-tree edit touches neither
/// `.git/HEAD` nor `.git/index`, so only elapsed time catches that — short
/// enough that a burst of searches shares one computation and the edit you just
/// made is reflected on the next search.
const BRANCH_FILES_TTL_SECS: i64 = 15;

/// A branch-file recomputation running alongside the search. The git work
/// happens on the thread; the store write waits for the main thread, since a
/// SQLite connection isn't shared.
struct BranchRefresh {
    handle: std::thread::JoinHandle<Vec<String>>,
    identity: String,
    stamp: String,
}

impl BranchRefresh {
    /// Wait for the recomputation and store it for the next query.
    fn store(self, store: &Store) {
        let Ok(files) = self.handle.join() else {
            return;
        };
        let _ = store.branch_files_set(&self.identity, &self.stamp, unix_now(), &files);
    }
}

/// The branch-changed file list, served from the store when it's still good.
/// Returns the list, plus a recomputation to collect after results print when
/// the stored one has aged out.
///
/// The list feeds a *ranking boost*, so serving a slightly old one costs a
/// little ranking quality, while recomputing it first would cost every search
/// the git diff behind it — which is O(tracked files). So the stored list is
/// served immediately and the refresh runs concurrently with the search rather
/// than after it, which usually hides its cost entirely. It feeds only the next
/// query, so nothing about this run's ranking depends on how the race lands.
///
/// The first search in a repo has nothing to serve and computes inline; that's
/// once per repo, like the first index.
fn cached_branch_files(
    store: &Store,
    root: &std::path::Path,
) -> (Vec<String>, Option<BranchRefresh>) {
    let identity = resolve_identity(store, root);
    let stamp = crate::index::branch_files_stamp(root);
    let cached = store.branch_files_get(&identity).ok().flatten();
    let now = unix_now();

    if let (Some((cached_stamp, at, files)), Some(stamp)) = (&cached, &stamp) {
        if cached_stamp == stamp && now.saturating_sub(*at) < BRANCH_FILES_TTL_SECS {
            return (files.clone(), None);
        }
        let owned_root = root.to_path_buf();
        let refresh = BranchRefresh {
            handle: std::thread::spawn(move || crate::index::branch_changed_files(&owned_root)),
            identity,
            stamp: stamp.clone(),
        };
        return (files.clone(), Some(refresh));
    }

    // Nothing cached (or nowhere to cache it, e.g. a worktree): compute inline.
    let files = crate::index::branch_changed_files(root);
    if let Some(stamp) = stamp {
        let _ = store.branch_files_set(&identity, &stamp, now, &files);
    }
    (files, None)
}

/// Whether the worktree has moved since it was indexed — a different HEAD, or
/// uncommitted edits. Split out from the store read so this half can run on its
/// own thread: `is_dirty` forks `git status`, which on a large worktree costs
/// more than the search it was gating (measured: 12.6ms of a 16.8ms query on a
/// 6k-file repo, against 0.1ms on a 54-file one).
///
/// `None` for `indexed_head` means we never recorded one, which counts as
/// changed — there's nothing to compare against, so assume work is due.
fn worktree_changed(cwd: &std::path::Path, indexed_head: Option<&str>) -> bool {
    let Some(head) = indexed_head else {
        return true;
    };
    crate::index::git_head(cwd).as_deref() != Some(head) || crate::index::is_dirty(cwd)
}

/// Settle warming once the answer is out: collect the staleness check started
/// back at setup, reindex if the worktree moved, and hand any remainder to a
/// detached child.
///
/// Called from *both* exits. The miss path matters as much as the render one —
/// a symbol added a moment ago is precisely a miss, and reindexing before we
/// exit is what makes the immediate retry hit.
#[allow(clippy::too_many_arguments)]
fn settle_warm(
    store: &Store,
    staleness: Option<std::thread::JoinHandle<bool>>,
    was_warming: bool,
    warming_ok: bool,
    root: Option<&std::path::Path>,
    active: &[String],
    query: &str,
    budget: Duration,
    no_wait: bool,
    identity: Option<&str>,
) -> bool {
    // A panicked check counts as changed: warming needlessly costs a little
    // time, skipping it wrongly serves a stale index.
    let changed = staleness.is_some_and(|h| h.join().unwrap_or(true));
    // Reindexing an edited worktree means sweeping every file to find the few
    // that moved — ~32ms on a 3000-file repo, and it was paid on *every* query
    // for as long as anything stayed uncommitted, which is exactly while you're
    // working. The shell shouldn't wait for that: hand it to the detached
    // child, which is what "the shell never waits on it" already promises
    // everywhere else.
    //
    // With detach off (the harness pins it so no child races a test's cleanup)
    // there's nobody to hand it to, so do it here as before.
    if changed
        && !no_wait
        && !warm_detach_enabled()
        && let Some(r) = root
        && let Ok(mut idx) = open_store()
    {
        crate::trace!("background warm (deferred, {budget:?}): worktree changed since index");
        let _ = crate::index::index_budgeted(&mut idx, r, active, budget, Some(query));
    }
    maybe_detach_warm(
        store,
        warming_ok && (was_warming || changed),
        changed,
        root,
        identity,
    );
    // Report only that work was *deferred*, which is what makes a miss
    // provisional. When the reindex ran inline just above (detach off), the
    // index is as current as we can make it and a miss is definitive.
    changed && warm_detach_enabled()
}

/// Inline warm budget on the search path. A *cap*, not a fixed delay:
/// `index_budgeted` returns the moment a full sweep finishes, so small/medium
/// repos index completely and pay only their real cost. The cap only bites a
/// genuinely huge, never-indexed repo — where a bigger budget buys a much better
/// first answer (a tiny budget can return nothing, since a git repo has no
/// live-scan fallback). 500 ms is a one-time cold-cache cost, trivial next to
/// scanning a large tree from scratch; the deferred pass and later queries fill
/// in the rest.
fn answer_warm_budget() -> Duration {
    env_budget("RQ_ANSWER_BUDGET_MS", 500)
}

/// Deferred warm budget, spent after results are printed: larger, to make real
/// progress on coverage per query while keeping each invocation snappy.
fn deferred_warm_budget() -> Duration {
    env_budget("RQ_DEFERRED_BUDGET_MS", 250)
}

/// Bound for the git-repo live-scan fallback (index empty, still warming): enough
/// to surface a result the warm hasn't reached, without an unbounded walk.
fn live_fallback_budget() -> Duration {
    env_budget("RQ_FALLBACK_BUDGET_MS", 250)
}

/// Budget for the *detached* warm child — generous, because nothing waits on
/// it: the shell got its results and the child runs niced in the background.
fn warm_bg_budget() -> Duration {
    env_budget("RQ_WARM_BUDGET_MS", 20_000)
}

/// Whether a search hands leftover warming to a detached child (default) or
/// finishes it in-process before exiting (`RQ_WARM_DETACH=0` — used by the
/// test harness for hermetic runs, and handy for debugging).
fn warm_detach_enabled() -> bool {
    std::env::var("RQ_WARM_DETACH").map_or(true, |v| v != "0")
}

/// How long a query may block indexing a cold repo before giving up with an
/// honest "still indexing" rather than a false miss. A generous backstop, not the
/// real cost: `index_budgeted` returns the moment the sweep completes, so any
/// normal repo finishes well under it, and an interactive run isn't bounded by it
/// at all (Ctrl-C escapes). It mainly bounds a programmatic caller on a
/// pathologically huge repo — where the partial index still persists for the next
/// query. `RQ_WAIT_BUDGET_MS=0` makes a programmatic caller non-blocking again —
/// it answers immediately from whatever's already indexed.
fn wait_budget() -> Duration {
    env_budget("RQ_WAIT_BUDGET_MS", 60_000)
}

/// Parse a `--wait` value into a duration: `<n>ms`, `<n>s`, `<n>m`, or a bare
/// `<n>` (seconds). Fractions are allowed (`1.5s`); `0` (any unit) means "don't
/// wait". A `clap` value parser, so an invalid duration is rejected at parse
/// time with a usage error.
fn parse_wait(s: &str) -> std::result::Result<Duration, String> {
    let s = s.trim();
    let bad = || format!("invalid duration {s:?} — use e.g. 50ms, 2s, 1m, or 0");
    // check "ms" before "s" so the "s" arm doesn't swallow it
    let (num, unit_ms) = if let Some(n) = s.strip_suffix("ms") {
        (n, 1.0)
    } else if let Some(n) = s.strip_suffix('s') {
        (n, 1_000.0)
    } else if let Some(n) = s.strip_suffix('m') {
        (n, 60_000.0)
    } else {
        // a bare number is seconds
        (s, 1_000.0)
    };
    let val: f64 = num.trim().parse().map_err(|_| bad())?;
    if !val.is_finite() || val < 0.0 {
        return Err(bad());
    }
    Ok(Duration::from_millis((val * unit_ms).round() as u64))
}

/// Set by the SIGINT handler during an interactive cold-start escalation. The
/// poll loop and the running index pass watch it, so Ctrl-C stops the wait
/// promptly and prints the best partial results instead of killing the process.
static INTERRUPTED: std::sync::atomic::AtomicBool = std::sync::atomic::AtomicBool::new(false);

extern "C" fn on_sigint(_: libc::c_int) {
    // Async-signal-safe: a lone relaxed atomic store — no allocation, no locks.
    INTERRUPTED.store(true, std::sync::atomic::Ordering::Relaxed);
}

/// Install the SIGINT handler once. Scoped to the escalation path: a normal fast
/// query keeps the default behavior (Ctrl-C kills it outright).
fn install_interrupt_handler() {
    static ONCE: std::sync::Once = std::sync::Once::new();
    ONCE.call_once(|| unsafe {
        let mut action: libc::sigaction = std::mem::zeroed();
        action.sa_sigaction = on_sigint as *const () as usize;
        libc::sigemptyset(&mut action.sa_mask);
        libc::sigaction(libc::SIGINT, &action, std::ptr::null_mut());
    });
}

/// Is a human watching stderr? True for a real terminal; `RQ_ASSUME_INTERACTIVE`
/// forces it on so the progress/Ctrl-C path is exercisable under test (where
/// stderr is a pipe), mirroring the `RQ_*_BUDGET_MS` testing knobs.
fn stderr_interactive() -> bool {
    std::io::stderr().is_terminal() || std::env::var_os("RQ_ASSUME_INTERACTIVE").is_some()
}

/// Whether to show the live "indexing…" progress heads-up and handle Ctrl-C
/// gracefully while a cold repo blocks — a human watching a plain-text terminal.
/// Piped / `--json` / `--ndjson` callers block silently instead (no line to draw,
/// no one to interrupt); the *decision to block* is the same for both.
fn show_progress(out: Output, interactive: bool) -> bool {
    interactive && matches!(out, Output::Text)
}

/// A short, friendly name for the repo being indexed — its directory name, for
/// the progress line.
fn repo_label(root: Option<&std::path::Path>) -> String {
    root.and_then(|r| r.file_name())
        .map(|n| n.to_string_lossy().into_owned())
        .unwrap_or_else(|| "repo".into())
}

/// Redraw the in-place "indexing…" progress line on stderr (kept off stdout so
/// piped/`--json` output stays clean). The file count comes from the index the
/// background pass is filling, so it climbs as warming proceeds.
fn draw_progress(store: &Store, identity: Option<&str>, label: &str) {
    let files = identity
        .and_then(|id| store.repository_id(id).ok().flatten())
        .and_then(|rid| store.repo_totals(rid).ok())
        .map_or(0, |(f, _)| f);
    eprint!("\r\x1b[Krq: indexing {label}… {files} files");
    let _ = std::io::stderr().flush();
}

/// Erase the progress line so results print to a clean terminal.
fn clear_progress() {
    eprint!("\r\x1b[K");
    let _ = std::io::stderr().flush();
}

/// Read a budget (milliseconds) from an env var, else the default. The env knobs
/// exist mainly for testing — a tiny budget reproduces large-repo warming
/// behavior on a small repo.
fn env_budget(var: &str, default_ms: u64) -> Duration {
    let ms = std::env::var(var)
        .ok()
        .and_then(|v| v.parse().ok())
        .unwrap_or(default_ms);
    Duration::from_millis(ms)
}

/// How many events to roll up per interaction. Bounded so the deferred pass
/// after a command stays quick.
const AGGREGATE_BATCH: usize = 256;

/// Recent raw events to retain after rollup (enough for repeat detection); the
/// rest, once aggregated, are pruned to keep the log from growing unbounded.
const KEEP_RECENT_EVENTS: i64 = 200;

/// The bounded background work run after a user interaction, once results are
/// out: roll new events into the learning rollup, then prune the raw log.
fn deferred_maintenance(store: &mut Store) {
    let _ = store.aggregate_events(AGGREGATE_BATCH);
    let _ = store.prune_events(KEEP_RECENT_EVENTS);
}

/// Hook entry point: record that `file` was opened/selected for `query`, then
/// amortize a chunk of event aggregation.
fn cmd_record(kind: &str, query: Option<&str>, file: &str, line: Option<i64>) -> ExitCode {
    let mut store = match open_store() {
        Ok(s) => s,
        Err(e) => return fail(format_args!("rq: cannot open database: {e}")),
    };
    let cwd = std::env::current_dir().unwrap_or_else(|_| PathBuf::from("."));
    let identity = crate::index::detect_identity(&cwd).to_string();
    let repo_id = store.repository_id(&identity).ok().flatten();

    // Store the path repo-relative so the rollup can resolve it against indexed
    // files.
    let rel = match repo_id.and_then(|id| store.checkout_root(id).ok().flatten()) {
        Some(root) => repo_relative(std::path::Path::new(&root), &cwd, file),
        None => file.to_string(),
    };
    let query_norm = query.map(|q| q.to_ascii_lowercase());

    if let Err(e) = store.record_event(kind, query_norm.as_deref(), repo_id, Some(&rel), line, None)
    {
        return fail(format_args!("rq record: {e}"));
    }
    deferred_maintenance(&mut store);
    ExitCode::SUCCESS
}

/// Candidate on-disk roots that may hold a hit's file, most-current first: every
/// checkout root recorded for the repo (newest first), then the cwd (for live
/// results, and as a fallback when the stored root is stale — a moved repo keeps
/// its old checkout row, and reading from that path fails). Callers read from the
/// first candidate that actually has the file.
fn hit_file_roots(
    store: &Store,
    repo_identity: &str,
    cwd: Option<&std::path::Path>,
) -> Vec<PathBuf> {
    let mut roots: Vec<PathBuf> = store
        .repository_id(repo_identity)
        .ok()
        .flatten()
        .map(|id| store.checkout_roots(id).unwrap_or_default())
        .unwrap_or_default()
        .into_iter()
        .map(PathBuf::from)
        .collect();
    if let Some(c) = cwd {
        let c = c.to_path_buf();
        if !roots.contains(&c) {
            roots.push(c);
        }
    }
    roots
}

/// The definition's source line (trimmed) for a hit — read from the first
/// candidate root that has the file (see [`hit_file_roots`]). Best-effort.
fn read_signature(
    store: &Store,
    repo_identity: &str,
    file: &str,
    line: i64,
    cwd: Option<&std::path::Path>,
) -> Option<String> {
    hit_file_roots(store, repo_identity, cwd)
        .into_iter()
        .find_map(|root| signature_in(&std::fs::read_to_string(root.join(file)).ok()?, line))
}

/// Confidence at or above which `--show` prints a body instead of a list. Exact
/// (1.0) and a unique prefix (0.9) clear it; a fuzzy or tied match does not — so
/// `--show` never prints a definition it isn't sure about.
const SHOW_CONFIDENCE: f64 = 0.85;

/// `--show`: if the top hit is confident, read and print its full source span
/// and return the exit code; otherwise return `None` to fall through to the
/// ranked list. Emits a single object in JSON/NDJSON (with a `body` field).
///
/// Printing the body *is* the selection — the caller asked for one definition
/// and consumed exactly this one — so it records the same signal `--open` does,
/// no follow-up call needed. Unlike a ranked list, there was no choice left to
/// the caller, and unlike a bare search, rq observed what was taken.
fn show_top_definition(
    store: &mut Store,
    hits: &mut [crate::search::Hit],
    query: &str,
    out: Output,
    cwd: Option<&std::path::Path>,
    current: Option<i64>,
    no_record: bool,
) -> Option<ExitCode> {
    let top = hits.first()?;
    if top.confidence < SHOW_CONFIDENCE {
        return None; // ambiguous / weak — let the caller list candidates
    }
    let end = top.end_line.unwrap_or(top.line);
    let body = read_span(store, &top.repo_identity, &top.file, top.line, end, cwd);
    hits[0].body = body;
    let top = &hits[0];
    let shown = (top.file.clone(), top.line);
    let code = match out {
        Output::Json | Output::Ndjson => {
            // fail loudly on a serialize error, like every other JSON path
            emit_json(out, top)
        }
        Output::Text => {
            let color = match_color();
            let c = color.as_deref();
            let name = hl(&top.name, query, c);
            let qualified = match &top.parent {
                Some(p) => format!("{name} · {p}"),
                None => name,
            };
            println!(
                "{}:{}  {} {}",
                hl_path(&top.file, query, c),
                top.line,
                top.kind,
                qualified
            );
            match (&top.body, &top.signature) {
                (Some(body), _) => println!("{body}"),
                // end_line unknown (pre-v4 row) → at least the definition line
                (None, Some(sig)) => println!("{sig}"),
                (None, None) => {}
            }
            ExitCode::SUCCESS
        }
    };

    // After the output, like every other post-interaction write.
    if !no_record {
        let (file, line) = shown;
        let _ = store.record_event(
            "select",
            Some(&query.to_ascii_lowercase()),
            current,
            Some(&file),
            Some(line),
            None,
        );
        deferred_maintenance(store);
    }
    Some(code)
}

/// The source span `start..=end` (1-based, inclusive) of a hit — the full
/// definition body for `--show`. Best-effort, mirroring [`read_signature`].
fn read_span(
    store: &Store,
    repo_identity: &str,
    file: &str,
    start: i64,
    end: i64,
    cwd: Option<&std::path::Path>,
) -> Option<String> {
    hit_file_roots(store, repo_identity, cwd)
        .into_iter()
        .find_map(|root| span_in(&std::fs::read_to_string(root.join(file)).ok()?, start, end))
}

/// Lines `start..=end` (1-based, inclusive) of already-read `content`, joined —
/// clamped to the file's bounds. `None` if `start` is past the end.
fn span_in(content: &str, start: i64, end: i64) -> Option<String> {
    let s = usize::try_from(start).ok()?.checked_sub(1)?;
    let lines: Vec<&str> = content.lines().collect();
    if s >= lines.len() {
        return None;
    }
    let e = usize::try_from(end).ok()?.clamp(s + 1, lines.len());
    Some(lines[s..e].join("\n"))
}

/// The trimmed source line `line` (1-based) of already-read `content`, if
/// non-empty — a symbol's definition line. Splitting this out lets `--symbols`
/// read one file once instead of re-reading it per symbol.
fn signature_in(content: &str, line: i64) -> Option<String> {
    let idx = usize::try_from(line).ok()?.checked_sub(1)?;
    let l = content.lines().nth(idx)?.trim();
    (!l.is_empty()).then(|| l.to_string())
}

/// One symbol in `rq --symbols` output. Same field names as a search hit
/// (`repo`, `signature`) for agent consistency, but no score/features — an
/// outline is structural, not ranked.
#[derive(serde::Serialize)]
struct SymbolOut {
    name: String,
    kind: String,
    language: String,
    file: String,
    line: i64,
    #[serde(skip_serializing_if = "Option::is_none")]
    end_line: Option<i64>,
    #[serde(skip_serializing_if = "Option::is_none")]
    parent: Option<String>,
    #[serde(skip_serializing_if = "Option::is_none")]
    visibility: Option<String>,
    repo: String,
    #[serde(skip_serializing_if = "Option::is_none")]
    signature: Option<String>,
}

/// `rq --symbols <file>`: list a file's symbols in line order — a structural
/// outline, not a ranked search. Warms the file's repo if it's cold/incomplete or
/// changed (same gate as search), then reads straight from the index. Honors
/// --kind/--lang filters and --json/--ndjson.
fn cmd_symbols(file_arg: &str, kinds: &[String], langs: &[String], out: Output) -> ExitCode {
    let mut store = match open_store() {
        Ok(s) => s,
        Err(e) => return fail(format_args!("rq: cannot open database: {e}")),
    };
    let cwd = std::env::current_dir().unwrap_or_else(|_| PathBuf::from("."));
    let root = crate::index::repo_root(&cwd).unwrap_or_else(|| cwd.clone());
    let rel = repo_relative(&root, &cwd, file_arg);

    let identity = resolve_identity(&store, &root);
    let coverage = store.coverage_status(&identity).ok().flatten();
    let warming_ok = crate::index::is_git_repo(&root) || coverage.is_some();
    let current = store.repository_id(&identity).ok().flatten();
    // Listing a file's symbols warms synchronously — there's no answer to get
    // out of the way of here, so the staleness fork is paid inline as before.
    let indexed_head = current.and_then(|id| store.indexed_head(id).ok().flatten());
    let needs_warm = warming_ok
        && (coverage.as_deref() != Some("complete")
            || worktree_changed(&root, indexed_head.as_deref()));
    if needs_warm {
        // Path-prioritize the warm toward the requested file so it indexes first.
        let budget = answer_warm_budget() + deferred_warm_budget();
        let _ = crate::index::index_budgeted(&mut store, &root, &[], budget, Some(&rel));
    }

    let Some(repo_id) = store.repository_id(&identity).ok().flatten() else {
        return emit_symbols(out, &[]); // unknown / un-indexed repo → nothing
    };
    let mut rows = match store.symbols_in_file(repo_id, &rel) {
        Ok(r) => r,
        Err(e) => return fail(format_args!("rq: {e}")),
    };
    if !kinds.is_empty() {
        rows.retain(|r| kinds.iter().any(|k| k == &r.kind));
    }
    if !langs.is_empty() {
        rows.retain(|r| langs.iter().any(|l| l == &r.language));
    }

    // Read the source once for signatures (every row is the same file), from
    // the first root that actually has it (see `hit_file_roots` — a moved repo
    // keeps a stale checkout row, so the first-recorded root can be dead).
    let content = hit_file_roots(&store, &identity, Some(&root))
        .iter()
        .find_map(|r| std::fs::read_to_string(r.join(&rel)).ok());
    let syms: Vec<SymbolOut> = rows
        .into_iter()
        .map(|r| SymbolOut {
            signature: content.as_deref().and_then(|c| signature_in(c, r.line)),
            name: r.name,
            kind: r.kind,
            language: r.language,
            file: r.file,
            line: r.line,
            end_line: r.end_line,
            parent: r.parent,
            visibility: r.visibility,
            repo: r.repo_identity,
        })
        .collect();
    emit_symbols(out, &syms)
}

/// Render the outline. Exit 0 if any symbols, non-zero if none — rq's exit-code
/// convention, matching how search reports an empty result per format.
fn emit_symbols(out: Output, syms: &[SymbolOut]) -> ExitCode {
    if syms.is_empty() {
        match out {
            Output::Json | Output::Ndjson => {
                let obj = serde_json::json!({ "status": "no_match" });
                let _ = emit_json(out, &obj); // exit code below carries the miss
            }
            Output::Text => eprintln!("no symbols"),
        }
        return ExitCode::FAILURE;
    }
    if let Some(code) = emit_rows(out, syms) {
        return code;
    }
    match out {
        Output::Json | Output::Ndjson => {}
        Output::Text => {
            for s in syms {
                let qualified = match &s.parent {
                    Some(p) => format!("{} · {p}", s.name),
                    None => s.name.clone(),
                };
                println!("{}:{}  {} {}", s.file, s.line, s.kind, qualified);
                if let Some(sig) = &s.signature {
                    println!("    {sig}");
                }
            }
        }
    }
    ExitCode::SUCCESS
}

/// A leading positional that names a symbol kind — the shorthand behind
/// `rq class Foo` and `rq method zoom`. Only the full, unambiguous keyword forms
/// count (never the single-letter `-k` shortcuts, which are far likelier to be a
/// real query). Returns the canonical kind, so it filters exactly like `--kind`.
fn keyword_kind(token: &str) -> Option<&'static str> {
    match token.to_ascii_lowercase().as_str() {
        "class" => Some("class"),
        "module" => Some("module"),
        "method" => Some("method"),
        "function" | "fn" => Some("function"),
        "struct" | "type" => Some("struct"),
        "enum" => Some("enum"),
        "trait" | "interface" => Some("trait"),
        _ => None,
    }
}

/// Peel a leading kind keyword off the query, so `rq class Foo` (or the quoted
/// `rq 'class Foo'`) means `-k class` + query `Foo`. The keyword must be followed
/// by a real query token — a bare `rq class` stays a search for a symbol literally
/// named `class`. Returns `(kind, query, trailing_path_dirs)`; the trailing dirs
/// are the rg-style positionals left after the query is consumed.
fn split_kind_keyword(
    target: String,
    dirs: Vec<String>,
) -> (Option<&'static str>, String, Vec<String>) {
    // Quoted form: the whole thing is one arg (`"class Foo"`), so peel the first
    // whitespace-separated word and keep the remainder as the query.
    if let Some((head, rest)) = target.split_once(char::is_whitespace) {
        let rest = rest.trim();
        if let Some(k) = keyword_kind(head)
            && !rest.is_empty()
        {
            return (Some(k), rest.to_string(), dirs);
        }
    } else if let Some(k) = keyword_kind(&target)
        && let Some((query, extra)) = dirs.split_first()
    {
        // Unquoted form: `rq class Foo` — the next positional is the query.
        return (Some(k), query.clone(), extra.to_vec());
    }
    (None, target, dirs)
}

/// Normalize a `--kind` value (name or shortcut) to a canonical symbol kind.
/// Unknown values pass through lowercased (so they simply match nothing).
fn canonical_kind(s: &str) -> String {
    match s.to_ascii_lowercase().as_str() {
        "c" | "class" => "class",
        "m" | "method" => "method",
        "f" | "fn" | "func" | "function" => "function",
        "mod" | "module" => "module",
        "s" | "struct" | "type" => "struct",
        "e" | "enum" => "enum",
        "t" | "trait" | "interface" => "trait",
        other => return other.to_string(),
    }
    .to_string()
}

/// Expand a `--lang` value to the language tag(s) it selects: a **prefix** of any
/// known language name (so `r` → ruby+rust, `p`/`py` → python, `g` → go,
/// `t` → typescript, `j` → javascript), plus a few non-prefix aliases
/// (`rb`→ruby, `rs`→rust, `golang`→go, `ts`/`tsx`→typescript,
/// `js`/`jsx`→javascript). An unknown value passes through lowercased so it
/// simply matches nothing.
fn canonical_langs(s: &str) -> Vec<String> {
    let t = s.to_ascii_lowercase();
    let alias = match t.as_str() {
        "rb" => Some("ruby"),
        "rs" => Some("rust"),
        "golang" => Some("go"),
        "ts" | "tsx" => Some("typescript"),
        "js" | "jsx" => Some("javascript"),
        _ => None,
    };
    let matched: Vec<String> = crate::lang::languages()
        .into_iter()
        .filter(|lang| alias == Some(*lang) || lang.starts_with(&t))
        .map(str::to_string)
        .collect();
    if matched.is_empty() { vec![t] } else { matched }
}

/// The ANSI SGR code for highlighting matches, or `None` to disable color.
/// Off unless stdout is a terminal; honors `NO_COLOR`; takes the match style
/// from `GREP_COLORS` (`mt`/`ms`) when set, else grep's default bold red.
fn match_color() -> Option<String> {
    if std::env::var_os("NO_COLOR").is_some() || !std::io::stdout().is_terminal() {
        return None;
    }
    let style = std::env::var("GREP_COLORS").ok().and_then(|gc| {
        gc.split(':').find_map(|e| {
            e.strip_prefix("mt=")
                .or_else(|| e.strip_prefix("ms="))
                .filter(|v| !v.is_empty())
                .map(str::to_string)
        })
    });
    Some(style.unwrap_or_else(|| "1;31".to_string()))
}

/// Highlight the chars of `text` that `query` matched (no-op when `color` is
/// `None`, e.g. piped output).
fn hl(text: &str, query: &str, color: Option<&str>) -> String {
    match color {
        Some(c) => highlight(text, &crate::search::match_positions(query, text), c),
        None => text.to_string(),
    }
}

/// Like [`hl`], but only over a path's filename — so matched chars light up in
/// `payrolls_controller.rb`, not scattered across the directory parts.
fn hl_path(path: &str, query: &str, color: Option<&str>) -> String {
    let Some(c) = color else {
        return path.to_string();
    };
    let base_byte = path.rfind('/').map(|b| b + 1).unwrap_or(0);
    let base_start = path[..base_byte].chars().count();
    // align on the filename *stem* (drop the extension), the same string the
    // scorer matched — so the query can't straggle into `.rb` instead of lighting
    // up the logical name (`employees_controller`)
    let stem = crate::search::path_stem(path);
    let positions: Vec<usize> = crate::search::match_positions(query, stem)
        .into_iter()
        .map(|p| p + base_start)
        .collect();
    highlight(path, &positions, c)
}

/// Wrap the matched character positions of `text` in an ANSI color run.
/// Consecutive matched chars share one escape sequence.
fn highlight(text: &str, positions: &[usize], color: &str) -> String {
    if positions.is_empty() {
        return text.to_string();
    }
    let matched: std::collections::HashSet<usize> = positions.iter().copied().collect();
    let mut out = String::new();
    let mut on = false;
    for (i, c) in text.chars().enumerate() {
        match (matched.contains(&i), on) {
            (true, false) => {
                out.push_str("\x1b[");
                out.push_str(color);
                out.push('m');
                on = true;
            }
            (false, true) => {
                out.push_str("\x1b[0m");
                on = false;
            }
            _ => {}
        }
        out.push(c);
    }
    if on {
        out.push_str("\x1b[0m");
    }
    out
}

/// Whether a repo-relative `file` sits under one of the `--path` directories
/// (prefix match on a path boundary). `app/services` matches
/// `app/services/refund.rb` but not `app/services_old/x.rb`.
fn under_any(file: &str, paths: &[String]) -> bool {
    paths.iter().any(|p| {
        let p = p.trim_start_matches("./").trim_end_matches('/');
        p.is_empty() || file == p || file.starts_with(&format!("{p}/"))
    })
}

/// Resolve a possibly-absolute or cwd-relative path to a repo-relative one.
fn repo_relative(root: &std::path::Path, cwd: &std::path::Path, file: &str) -> String {
    let p = std::path::Path::new(file);
    let abs = if p.is_absolute() {
        p.to_path_buf()
    } else {
        cwd.join(p)
    };
    let abs = abs.canonicalize().unwrap_or(abs);
    abs.strip_prefix(root)
        .map(|r| r.to_string_lossy().into_owned())
        .unwrap_or_else(|_| file.to_string())
}

/// Revalidate the files behind the top hits against disk, refreshing any that
/// changed and forgetting any that were deleted. Returns true if anything
/// changed (so the caller re-runs the search).
fn revalidate_top(store: &mut Store, hits: &[crate::search::Hit]) -> bool {
    use std::collections::HashSet;
    let mut seen = HashSet::new();
    let mut changed = false;
    for hit in hits {
        if !seen.insert((hit.repo_identity.clone(), hit.file.clone())) {
            continue;
        }
        let Some(repo_id) = store.repository_id(&hit.repo_identity).ok().flatten() else {
            continue;
        };
        let Some(root) = store.checkout_root(repo_id).ok().flatten() else {
            continue;
        };
        if let Ok(crate::index::Refresh::Updated) =
            crate::index::refresh_file(store, repo_id, std::path::Path::new(&root), &hit.file)
        {
            changed = true;
        }
    }
    changed
}

/// The repository's normalized identity for `cwd`, cache-first: look it up by
/// the canonical cwd (the checkout root indexing records), so a known repo (git
/// or explicitly `--index`ed) costs no `git` fork. On a cache miss, a non-git
/// dir resolves to its `local:` path directly (still no fork); only a git work
/// tree we haven't seen yet pays a `git remote` call.
fn resolve_identity(store: &Store, cwd: &std::path::Path) -> String {
    if let Ok(canon) = cwd.canonicalize() {
        if let Ok(Some(identity)) = store.identity_for_root(&canon.to_string_lossy()) {
            return identity;
        }
        if crate::index::repo_root(cwd).is_none() {
            return crate::core::RepoIdentity::local(&canon.to_string_lossy()).to_string();
        }
    }
    crate::index::detect_identity(cwd).to_string()
}

fn cmd_index(path: Option<PathBuf>, subdirs: &[String], out: Output) -> ExitCode {
    let explicit = path.is_some();
    let target = path.unwrap_or_else(|| PathBuf::from("."));
    // Normalize to the repo root: the index is repo-root-relative, so indexing
    // from a subdirectory must still key off the root (a subdir-relative index
    // would mismatch a later search and get reconciled away). `--path` scopes a
    // subset; outside git the target is used as-is.
    let root = crate::index::repo_root(&target).unwrap_or_else(|| target.clone());
    // An explicit TARGET *inside* the repo scopes the index to that subtree — the
    // user pointed at a subdir, not the whole repo, and shouldn't pay to walk
    // everything. Folded in alongside any `--path` subdirs. (A bare `rq --index`
    // with no target still walks the whole repo.)
    let mut subdirs = subdirs.to_vec();
    if explicit
        && let (Ok(t), Ok(r)) = (target.canonicalize(), root.canonicalize())
        && t != r
        && let Ok(rel) = t.strip_prefix(&r)
        && !rel.as_os_str().is_empty()
    {
        subdirs.push(rel.to_string_lossy().into_owned());
    }
    let mut store = match open_store() {
        Ok(s) => s,
        Err(e) => return fail(format_args!("rq: cannot open database: {e}")),
    };
    let identity = crate::index::detect_identity(&root).to_string();
    match crate::index::index_under(&mut store, &root, &subdirs) {
        Ok(stats) => {
            let subtree = !subdirs.is_empty();
            // distinguish this run's incremental work from the index totals
            let totals = store
                .repository_id(&identity)
                .ok()
                .flatten()
                .and_then(|id| store.repo_totals(id).ok());
            match out {
                Output::Json | Output::Ndjson => {
                    let (files, symbols) = match totals {
                        Some((f, s)) => (Some(f), Some(s)),
                        None => (None, None),
                    };
                    return emit_json(
                        out,
                        &serde_json::json!({
                            "repo": identity,
                            "scope": if subtree { "subtree" } else { "full" },
                            "files_added": stats.files_indexed,
                            "symbols_added": stats.symbols,
                            "files": files,
                            "symbols": symbols,
                        }),
                    );
                }
                Output::Text => {
                    let scope = if subtree { " (subtree seed)" } else { "" };
                    match totals {
                        Some((files, symbols)) => println!(
                            "{} file(s)/{} symbol(s) added this run; index{scope} now {files} files, {symbols} symbols",
                            stats.files_indexed, stats.symbols
                        ),
                        None => println!(
                            "{} file(s)/{} symbol(s) added this run{scope}",
                            stats.files_indexed, stats.symbols
                        ),
                    }
                }
            }
            ExitCode::SUCCESS
        }
        Err(e) => fail(format_args!("rq --index: {e}")),
    }
}

fn cmd_drop(target: Option<String>, out: Output) -> ExitCode {
    let mut store = match open_store() {
        Ok(s) => s,
        Err(e) => return fail(format_args!("rq: cannot open database: {e}")),
    };

    // Resolve the repo to drop: TARGET as a path (→ repo root → identity, like
    // --index), falling back to TARGET as a literal identity string — so cruft
    // shown by --status can be dropped by name even if the checkout is gone.
    let path = PathBuf::from(target.clone().unwrap_or_else(|| ".".to_string()));
    let root = crate::index::repo_root(&path).unwrap_or(path);
    let from_path = crate::index::detect_identity(&root).to_string();
    let resolved = match store.repository_id(&from_path) {
        Ok(Some(id)) => Some((from_path.clone(), id)),
        Ok(None) => target.as_deref().and_then(|s| {
            store
                .repository_id(s)
                .ok()
                .flatten()
                .map(|id| (s.to_string(), id))
        }),
        Err(e) => return fail(format_args!("rq --drop: {e}")),
    };

    let Some((identity, repo_id)) = resolved else {
        // nothing to drop — idempotent. `dropped: false` lets a script tell.
        return match out {
            Output::Text => {
                println!("not indexed: {from_path}");
                ExitCode::SUCCESS
            }
            _ => emit_json(
                out,
                &serde_json::json!({"repo": from_path, "files": 0, "symbols": 0, "dropped": false}),
            ),
        };
    };

    let (files, symbols) = store.repo_totals(repo_id).unwrap_or((0, 0));
    match store.drop_repository(repo_id) {
        Ok(()) => match out {
            Output::Text => {
                println!("dropped {identity} ({files} file(s), {symbols} symbol(s))");
                ExitCode::SUCCESS
            }
            _ => emit_json(
                out,
                &serde_json::json!({"repo": identity, "files": files, "symbols": symbols, "dropped": true}),
            ),
        },
        Err(e) => fail(format_args!("rq --drop: {e}")),
    }
}

/// Print a single value as JSON: `--json` pretty, `--ndjson` compact one-liner.
/// Used by the single-object operations (`--index`, `--drop`) and the
/// no-match status objects; [`emit_rows`] is the multi-row twin.
fn emit_json<T: serde::Serialize>(out: Output, value: &T) -> ExitCode {
    let rendered = if out == Output::Json {
        serde_json::to_string_pretty(value)
    } else {
        serde_json::to_string(value)
    };
    match rendered {
        Ok(s) => {
            println!("{s}");
            ExitCode::SUCCESS
        }
        Err(e) => fail(format_args!("rq: {e}")),
    }
}

/// Print a row set as structured output: `--json` one pretty array, `--ndjson`
/// one compact object per line. Returns `Some(exit)` on a serialization
/// failure, `None` on success (Text output is the caller's business).
fn emit_rows<T: serde::Serialize>(out: Output, rows: &[T]) -> Option<ExitCode> {
    match out {
        Output::Json => match serde_json::to_string_pretty(rows) {
            Ok(s) => println!("{s}"),
            Err(e) => return Some(fail(format_args!("rq: {e}"))),
        },
        Output::Ndjson => {
            for r in rows {
                match serde_json::to_string(r) {
                    Ok(line) => println!("{line}"),
                    Err(e) => return Some(fail(format_args!("rq: {e}"))),
                }
            }
        }
        Output::Text => {}
    }
    None
}

fn cmd_status(out: Output) -> ExitCode {
    let store = match open_store() {
        Ok(s) => s,
        Err(e) => return fail(format_args!("rq: cannot open database: {e}")),
    };
    let rows = match store.coverage_overview() {
        Ok(rows) => rows,
        Err(e) => return fail(format_args!("rq --status: {e}")),
    };
    if let Some(code) = emit_rows(out, &rows) {
        return code;
    }
    match out {
        Output::Json | Output::Ndjson => {}
        Output::Text if rows.is_empty() => {
            println!("no repositories indexed yet (try `rq --index`)");
        }
        Output::Text => {
            for r in &rows {
                println!(
                    "{:<10} {:>6} files  {:>7} symbols  {}",
                    r.status, r.files, r.symbols, r.identity
                );
            }
        }
    }
    ExitCode::SUCCESS
}

/// `--usage`: how rq has actually been called, by day, caller, and flag set.
/// Reads `usage_daily`, which outlives the pruned raw event log.
fn cmd_usage(out: Output) -> ExitCode {
    let store = match open_store() {
        Ok(s) => s,
        Err(e) => return fail(format_args!("rq: cannot open database: {e}")),
    };
    let rows = match store.usage_overview() {
        Ok(rows) => rows,
        Err(e) => return fail(format_args!("rq --usage: {e}")),
    };
    if let Some(code) = emit_rows(out, &rows) {
        return code;
    }
    match out {
        Output::Json | Output::Ndjson => {}
        Output::Text if rows.is_empty() => {
            println!("no usage recorded yet");
        }
        Output::Text => {
            // Five columns of bare numbers need naming; `--status` gets away
            // without a header because its columns carry their own units.
            println!(
                "{:<10}  {:<16} {:>8} {:>7}  flags",
                "day", "caller", "found", "missed"
            );
            for r in &rows {
                let flags = if r.flags.is_empty() { "-" } else { &r.flags };
                println!(
                    "{:<10}  {:<16} {:>8} {:>7}  {}",
                    r.day,
                    r.source,
                    r.searches - r.misses,
                    r.misses,
                    flags
                );
            }
            let searches: i64 = rows.iter().map(|r| r.searches).sum();
            let misses: i64 = rows.iter().map(|r| r.misses).sum();
            let plural = if searches == 1 { "search" } else { "searches" };
            println!("{searches} {plural}, {misses} found nothing");
        }
    }
    // Nothing recorded is the "nothing happened" case, like an empty --status.
    if rows.is_empty() {
        return ExitCode::from(1);
    }
    ExitCode::SUCCESS
}

/// Open the rq database, honoring `RQ_DB` and creating parent dirs.
fn open_store() -> Result<Store, Box<dyn std::error::Error>> {
    let path = db_path()?;
    if let Some(parent) = path.parent() {
        std::fs::create_dir_all(parent)?;
    }
    Ok(Store::open(&path)?)
}

/// Resolve the database path: `$RQ_DB`, else `$HOME/.local/share/rq/rq.db`.
fn db_path() -> Result<PathBuf, Box<dyn std::error::Error>> {
    if let Ok(p) = std::env::var("RQ_DB") {
        return Ok(PathBuf::from(p));
    }
    let home = std::env::var("HOME")?;
    Ok(PathBuf::from(home).join(".local/share/rq/rq.db"))
}

fn fail(args: std::fmt::Arguments) -> ExitCode {
    eprintln!("{args}");
    ExitCode::FAILURE
}

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

    #[test]
    fn open_menu_choice_parsing() {
        // blank reply takes the top match; a valid number maps to its index
        assert_eq!(parse_choice("\n", 5), Some(0));
        assert_eq!(parse_choice("  ", 5), Some(0));
        assert_eq!(parse_choice("3", 5), Some(2));
        assert_eq!(parse_choice("5", 5), Some(4));
        // out of range, zero, or non-numeric aborts
        assert_eq!(parse_choice("6", 5), None);
        assert_eq!(parse_choice("0", 5), None);
        assert_eq!(parse_choice("q", 5), None);
    }

    #[test]
    fn wait_duration_parsing() {
        use std::time::Duration;
        // units: ms / s / m, and a bare number is seconds
        assert_eq!(parse_wait("50ms"), Ok(Duration::from_millis(50)));
        assert_eq!(parse_wait("2s"), Ok(Duration::from_secs(2)));
        assert_eq!(parse_wait("1m"), Ok(Duration::from_secs(60)));
        assert_eq!(parse_wait("250"), Ok(Duration::from_secs(250)));
        // fractions and zero
        assert_eq!(parse_wait("1.5s"), Ok(Duration::from_millis(1500)));
        assert_eq!(parse_wait("0"), Ok(Duration::ZERO));
        assert!(parse_wait("0s").unwrap().is_zero());
        // surrounding whitespace is tolerated
        assert_eq!(parse_wait(" 2s "), Ok(Duration::from_secs(2)));
        // garbage, empty, and negatives are rejected (a usage error at parse time)
        assert!(parse_wait("2x").is_err());
        assert!(parse_wait("").is_err());
        assert!(parse_wait("s").is_err());
        assert!(parse_wait("-1s").is_err());
    }

    #[test]
    fn leading_kind_keyword_becomes_a_kind_filter() {
        let d = |s: &[&str]| s.iter().map(|x| x.to_string()).collect::<Vec<_>>();
        // unquoted: `rq class Widget` — keyword + next positional is the query
        assert_eq!(
            split_kind_keyword("class".into(), d(&["Widget"])),
            (Some("class"), "Widget".into(), vec![])
        );
        // quoted: `rq 'method zoom'` — one arg, peel the first word
        assert_eq!(
            split_kind_keyword("method zoom".into(), vec![]),
            (Some("method"), "zoom".into(), vec![])
        );
        // `fn` is an alias for function; composes with a qualifier tail
        assert_eq!(
            split_kind_keyword("fn".into(), d(&["Foo::run"])),
            (Some("function"), "Foo::run".into(), vec![])
        );
        // extra positionals after the query stay as rg-style path dirs
        assert_eq!(
            split_kind_keyword("struct".into(), d(&["Gadget", "src"])),
            (Some("struct"), "Gadget".into(), d(&["src"]))
        );
    }

    #[test]
    fn a_bare_or_non_keyword_query_is_left_alone() {
        let d = |s: &[&str]| s.iter().map(|x| x.to_string()).collect::<Vec<_>>();
        // a keyword with no following query token is a search for that literal name
        assert_eq!(
            split_kind_keyword("class".into(), vec![]),
            (None, "class".into(), vec![])
        );
        // an ordinary query is untouched, trailing dirs preserved
        assert_eq!(
            split_kind_keyword("Widget".into(), d(&["app"])),
            (None, "Widget".into(), d(&["app"]))
        );
        // single-letter `-k` shortcuts are NOT keywords here (too query-like)
        assert_eq!(
            split_kind_keyword("c".into(), d(&["Foo"])),
            (None, "c".into(), d(&["Foo"]))
        );
    }

    #[test]
    fn a_language_selects_by_prefix_or_alias() {
        // a prefix can name more than one language
        assert_eq!(canonical_langs("r"), ["ruby", "rust"]);
        assert_eq!(canonical_langs("t"), ["typescript"]);
        // the names people actually type aren't prefixes of the tag
        assert_eq!(canonical_langs("ts"), ["typescript"]);
        assert_eq!(canonical_langs("jsx"), ["javascript"]);
        assert_eq!(canonical_langs("rb"), ["ruby"]);
        // an unknown value passes through and simply matches nothing
        assert_eq!(canonical_langs("COBOL"), ["cobol"]);
    }

    #[test]
    fn a_kind_normalizes_language_specific_spellings() {
        assert_eq!(canonical_kind("f"), "function");
        // TypeScript's spellings land on the shared model's kinds
        assert_eq!(canonical_kind("interface"), "trait");
        assert_eq!(canonical_kind("type"), "struct");
        // …and work as the leading-keyword shorthand too
        let d = |s: &[&str]| s.iter().map(|x| x.to_string()).collect::<Vec<_>>();
        assert_eq!(
            split_kind_keyword("interface".into(), d(&["Renderer"])),
            (Some("trait"), "Renderer".into(), vec![])
        );
    }

    #[test]
    fn highlight_wraps_matched_runs() {
        assert_eq!(
            highlight("FooThing", &[0, 1, 2], "1;31"),
            "\u{1b}[1;31mFoo\u{1b}[0mThing"
        );
        // scattered matches get separate runs
        assert_eq!(
            highlight("FooThing", &[0, 3], "1"),
            "\u{1b}[1mF\u{1b}[0moo\u{1b}[1mT\u{1b}[0mhing"
        );
        // nothing matched → unchanged
        assert_eq!(highlight("FooThing", &[], "1;31"), "FooThing");
    }

    #[test]
    fn progress_ui_only_for_an_interactive_text_terminal() {
        // a person at a terminal, plain text → live progress + graceful Ctrl-C
        assert!(show_progress(Output::Text, true));

        // machine-readable output blocks silently (no progress line to corrupt it)
        assert!(!show_progress(Output::Json, true));
        assert!(!show_progress(Output::Ndjson, true));

        // not a terminal (a script/agent/pipe) — block, but without the UI
        assert!(!show_progress(Output::Text, false));
    }

    #[test]
    fn repo_label_uses_the_directory_name() {
        assert_eq!(
            repo_label(Some(std::path::Path::new("/src/widgets"))),
            "widgets"
        );
        assert_eq!(repo_label(None), "repo");
    }

    #[test]
    fn hl_path_highlights_the_stem_not_the_extension() {
        // matching `employeescontroller`, the highlight covers the logical name in
        // the stem and never straggles into `.rb`
        let out = hl_path(
            "app/employees_controller.rb",
            "employeescontroller",
            Some("1;31"),
        );
        assert!(
            out.starts_with("app/\u{1b}[1;31memployees"),
            "stem highlighted: {out:?}"
        );
        assert!(
            out.ends_with("controller\u{1b}[0m.rb"),
            "`.rb` left un-highlighted: {out:?}"
        );
    }
}