//! Commands that act on the local repository and working copy.

use super::format::{
    author_name, deps_line, deps_of, plural, short_id, short_meta_id, signature_line,
    signature_mark, subject_of, when,
};
use super::json;
use super::open;
use super::ui;
use anyhow::Result;
use oxy_core::objects::ChangeKind;
use oxy_core::repo::SignatureStatus;
use oxy_core::repo::{render_change, ChangeStatus, Repo};
use std::path::PathBuf;

pub fn init(path: Option<PathBuf>, bare: bool) -> Result<i32> {
    let path = path.unwrap_or(std::env::current_dir()?);
    let repo = if bare {
        Repo::init_bare(&path)?
    } else {
        Repo::init(&path)?
    };
    println!(
        "{} {}oxy repository in {}",
        ui::done("Initialized"),
        if bare { "bare " } else { "" },
        ui::path(repo.root().display())
    );
    println!(
        "{}",
        ui::kv("bookmark", ui::bookmark(&repo.config.bookmark))
    );
    println!(
        "{}",
        ui::kv(
            "author",
            format!(
                "{} <{}>",
                ui::author(&repo.config.author_name),
                repo.config.author_email
            )
        )
    );
    Ok(0)
}

fn status_tag(s: ChangeStatus) -> &'static str {
    match s {
        ChangeStatus::Added => "A",
        ChangeStatus::Modified => "M",
        ChangeStatus::Removed => "D",
        ChangeStatus::Renamed => "R",
        ChangeStatus::ModeChanged => "X",
        ChangeStatus::ConflictEdited => "C!",
        ChangeStatus::Resolved => "V",
    }
}

pub fn status(json: bool) -> Result<i32> {
    let repo = open()?;
    // Clean by the manifest alone: no history to load (oxygen#35).
    if !json && repo.clean_by_manifest()? {
        let (_, wc) = repo.working_copy()?;
        let heads = repo.bookmark_heads()?;
        println!(
            "{} {}{}working copy {}{}{}",
            ui::dim("On"),
            ui::bookmark(&repo.config.bookmark),
            ui::sep(),
            ui::id(wc.change_id.short(8)),
            ui::sep(),
            ui::dim(plural(heads.len(), "head"))
        );
        println!(
            "  {} {}",
            ui::ok(ui::glyph("✔", "*")),
            ui::dim("nothing to commit, working copy clean")
        );
        return Ok(0);
    }
    let sp = ui::spinner("Snapshotting the working copy…");
    let snap = repo.snapshot_status("oxy status")?;
    let heads = repo.bookmark_heads()?;
    sp.clear();
    if json {
        println!("{}", repo.status_json(&snap)?);
        return Ok(if snap.base_snapshot.is_conflicted() {
            2
        } else {
            0
        });
    }
    println!(
        "{} {}{}working copy {}{}{}",
        ui::dim("On"),
        ui::bookmark(&repo.config.bookmark),
        ui::sep(),
        ui::id(snap.wc.change_id.short(8)),
        ui::sep(),
        ui::dim(plural(heads.len(), "head"))
    );
    if snap.statuses.is_empty() {
        println!(
            "  {} {}",
            ui::ok(ui::glyph("✔", "*")),
            ui::dim("nothing to commit, working copy clean")
        );
    } else {
        println!();
        for s in &snap.statuses {
            println!(
                "  {} {}",
                ui::status_mark(status_tag(s.status)),
                ui::path(&s.path)
            );
        }
    }
    if !snap.base_snapshot.is_conflicted() {
        return Ok(0);
    }
    println!();
    println!(
        "{} {}",
        ui::section(ui::err("Conflicts")),
        ui::dim("edit the marked files, or the .oxy-conflict-N candidates, then commit")
    );
    for c in &snap.base_snapshot.tree.conflicts {
        println!("  {} tree: {c:?}", ui::err(ui::glyph("✱", "!")));
    }
    for (p, f) in &snap.base_snapshot.files {
        if f.is_conflicted() {
            let state = match snap
                .statuses
                .iter()
                .find(|s| s.path == *p)
                .map(|s| s.status)
            {
                Some(ChangeStatus::Resolved) => {
                    ui::ok(format!("{} resolved in working copy", ui::glyph("✔", "*")))
                }
                Some(ChangeStatus::ConflictEdited) => {
                    ui::warn(format!("{} markers remain", ui::glyph("‼", "!")))
                }
                _ => ui::err(format!("{} unresolved", ui::glyph("✱", "!"))),
            };
            println!("  {}  {state}", ui::path(p));
        }
    }
    Ok(2)
}

pub fn commit(
    message: &str,
    depends_on: &[String],
    paths: &[String],
    interactive: bool,
    hunks: &[usize],
) -> Result<i32> {
    let repo = open()?;
    let mut deps = Vec::new();
    for d in depends_on {
        deps.push(repo.resolve_change(d)?);
    }
    let selection = if !hunks.is_empty() {
        oxy_core::repo::Selection::Hunks(hunks.to_vec())
    } else if interactive {
        let (_, hunks) = repo.hunks()?;
        if hunks.is_empty() {
            anyhow::bail!("nothing to commit: the working copy matches its base");
        }
        let hunks: Vec<_> = hunks
            .into_iter()
            .filter(|h| {
                paths.is_empty()
                    || paths.iter().any(|p| {
                        h.path == *p || h.path.starts_with(&format!("{}/", p.trim_end_matches('/')))
                    })
            })
            .collect();
        let mut chosen = Vec::new();
        let stdin = std::io::stdin();
        let mut take_rest = false;
        for (n, h) in hunks.iter().enumerate() {
            if take_rest {
                chosen.push(h.index);
                continue;
            }
            println!(
                "{} {} {}",
                ui::section(format!("hunk {} of {}", n + 1, hunks.len())),
                ui::path(&h.path),
                ui::dim(format!("(#{})", h.index))
            );
            for line in h.text.lines() {
                let styled = if line.starts_with('+') {
                    ui::ok(line)
                } else if line.starts_with('-') {
                    ui::err(line)
                } else {
                    ui::dim(line)
                };
                println!("  {styled}");
            }
            loop {
                print!(
                    "{} ",
                    ui::warn("Commit this hunk? [y]es [n]o [a]ll remaining [q]uit:")
                );
                use std::io::Write as _;
                std::io::stdout().flush()?;
                let mut answer = String::new();
                if stdin.read_line(&mut answer)? == 0 {
                    anyhow::bail!("aborted");
                }
                match answer.trim() {
                    "y" | "Y" => {
                        chosen.push(h.index);
                        break;
                    }
                    "n" | "N" | "" => break,
                    "a" | "A" => {
                        chosen.push(h.index);
                        take_rest = true;
                        break;
                    }
                    "q" | "Q" => anyhow::bail!("aborted; nothing committed"),
                    _ => continue,
                }
            }
        }
        if chosen.is_empty() {
            anyhow::bail!("no hunks chosen; nothing committed");
        }
        oxy_core::repo::Selection::Hunks(chosen)
    } else if paths.is_empty() {
        oxy_core::repo::Selection::All
    } else {
        oxy_core::repo::Selection::Paths(paths.to_vec())
    };
    let sp = ui::spinner("Committing…");
    let h = repo.commit_selection(message, &deps, &selection)?;
    let c = repo.store().get_change(&h)?;
    sp.done(&format!(
        "{} {} {}  {}",
        ui::done("Committed"),
        ui::id(short_id(&c)),
        ui::hash(format!("#{}", h.short(12))),
        ui::subject(subject_of(message))
    ));
    if !matches!(selection, oxy_core::repo::Selection::All) {
        let rest = repo.snapshot_status("oxy commit")?;
        if !rest.statuses.is_empty() {
            println!(
                "  {} {}",
                ui::note(),
                ui::dim(format!(
                    "{} left uncommitted",
                    plural(rest.statuses.len(), "path")
                ))
            );
        }
    }
    Ok(0)
}

pub fn blame(path: &str, json: bool) -> Result<i32> {
    let repo = open()?;
    let lines = repo.blame(path)?;
    if json {
        let items = lines.iter().map(|l| {
            format!(
                "{{\"line\":{},\"change_id\":{},\"hash\":{},\"index\":{},\"author\":{},\"when_ms\":{}}}",
                l.line,
                oxy_core::repo::json_str(&l.change_id.to_hex()),
                oxy_core::repo::json_str(&l.hash.to_hex()),
                l.index,
                oxy_core::repo::json_str(&l.author),
                l.when_ms
            )
        });
        println!("{}", oxy_core::repo::json_array(items));
        return Ok(0);
    }
    let width = lines
        .iter()
        .map(|l| l.author.chars().count())
        .max()
        .unwrap_or(0)
        .min(20);
    let digits = lines.len().to_string().len();
    for l in &lines {
        let author: String = l.author.chars().take(20).collect();
        let text = String::from_utf8_lossy(&l.text);
        println!(
            "{} {} {} {:>digits$}{} {}",
            ui::id(l.change_id.short(8)),
            ui::author(format!("{author:<width$}")),
            ui::dim(ui::ago(l.when_ms)),
            l.line,
            ui::dim(ui::glyph("│", "|")),
            text.trim_end_matches('\n')
        );
    }
    Ok(0)
}

fn bisect_report(repo: &Repo, step: &oxy_core::repo::BisectStep) -> Result<i32> {
    use oxy_core::repo::BisectStep::*;
    match step {
        NeedMarks { good, bad } => {
            println!(
                "{} {} {}",
                ui::note(),
                ui::dim(format!("{good} good, {bad} bad;")),
                ui::dim(if *good == 0 {
                    "mark a known-good change or bookmark: oxy bisect good CHANGE"
                } else {
                    "mark a known-bad change or bookmark: oxy bisect bad CHANGE"
                })
            );
            Ok(0)
        }
        Testing {
            heads,
            remaining,
            steps_left,
        } => {
            println!(
                "{} {} {}",
                ui::done("Testing"),
                ui::dim(format!(
                    "{} in the state under test;",
                    plural(heads.len(), "head")
                )),
                ui::dim(format!(
                    "{remaining} candidates left, about {steps_left} more steps"
                ))
            );
            println!(
                "  {} {}",
                ui::note(),
                ui::dim("run your test, then oxy bisect good | bad | skip")
            );
            Ok(0)
        }
        Found { culprit } => {
            let c = repo.store().get_change(culprit)?;
            println!(
                "{} {} {}  {}",
                ui::done("Found"),
                ui::id(short_id(&c)),
                ui::hash(format!("#{}", culprit.short(12))),
                ui::subject(subject_of(&c.message))
            );
            println!("  {} {}", ui::note(), ui::dim("the first change whose inclusion makes the state bad; oxy bisect reset to return"));
            Ok(0)
        }
        Inconclusive { candidates } => {
            println!(
                "{} {}",
                ui::caution(),
                ui::warn(format!(
                    "every remaining candidate was skipped ({}); oxy bisect reset to return",
                    plural(candidates.len(), "change")
                ))
            );
            Ok(1)
        }
    }
}

pub fn bisect_start() -> Result<i32> {
    let repo = open()?;
    repo.bisect_start()?;
    println!(
        "{} bisect; {}",
        ui::done("Started"),
        ui::dim("now: oxy bisect good CHANGE and oxy bisect bad CHANGE")
    );
    Ok(0)
}

pub fn bisect_mark(good: Option<bool>, changes: &[String]) -> Result<i32> {
    let repo = open()?;
    let mut heads = Vec::new();
    for c in changes {
        heads.extend(repo.resolve_heads(c)?);
    }
    let step = repo.bisect_mark(good, &heads)?;
    bisect_report(&repo, &step)
}

pub fn bisect_run(command: &[String]) -> Result<i32> {
    let repo = open()?;
    let step = repo.bisect_run(command)?;
    bisect_report(&repo, &step)
}

pub fn bisect_status(as_json: bool) -> Result<i32> {
    let repo = open()?;
    if as_json {
        use oxy_core::repo::BisectStep::*;
        let v = match repo.bisect_status()? {
            None => "null".to_string(),
            Some(NeedMarks { good, bad }) => json::obj([
                ("state", json::s("need-marks")),
                ("good", json::n(good)),
                ("bad", json::n(bad)),
            ]),
            Some(Testing {
                heads,
                remaining,
                steps_left,
            }) => json::obj([
                ("state", json::s("testing")),
                ("heads", json::hashes(&heads)),
                ("remaining", json::n(remaining)),
                ("steps_left", json::n(steps_left)),
            ]),
            Some(Found { culprit }) => json::obj([
                ("state", json::s("found")),
                ("culprit", json::s(&culprit.to_hex())),
            ]),
            Some(Inconclusive { candidates }) => json::obj([
                ("state", json::s("inconclusive")),
                ("candidates", json::hashes(&candidates)),
            ]),
        };
        println!("{v}");
        return Ok(0);
    }
    match repo.bisect_status()? {
        None => {
            println!("{}", ui::dim("No bisect in progress."));
            Ok(0)
        }
        Some(step) => bisect_report(&repo, &step),
    }
}

pub fn bisect_reset() -> Result<i32> {
    let repo = open()?;
    repo.bisect_reset()?;
    println!("{} bisect; working copy restored", ui::done("Reset"));
    Ok(0)
}

/// The log: one entry per change, newest first, joined by a rail. The
/// default view is the subject and a metadata line; `verbose` adds the full
/// message, dependencies, and the authenticating key.
fn signature_json(repo: &Repo, h: &oxy_core::hash::ChangeHash) -> Result<String> {
    Ok(match repo.authenticate_change(h)? {
        SignatureStatus::Unsigned => json::obj([("status", json::s("unsigned"))]),
        SignatureStatus::Valid {
            key,
            name,
            email,
            sealed,
            revoked,
        } => json::obj([
            ("status", json::s(if sealed { "sealed" } else { "signed" })),
            ("key", json::s(&key.to_hex())),
            ("name", json::s(&name)),
            ("email", json::s(&email)),
            ("revoked", json::b(revoked)),
        ]),
        SignatureStatus::Invalid(why) => {
            json::obj([("status", json::s("invalid")), ("reason", json::s(&why))])
        }
    })
}

fn log_entry_json(repo: &Repo, e: &oxy_core::repo::LogEntry) -> Result<String> {
    let c = &e.change;
    Ok(json::obj([
        ("hash", json::s(&e.hash.to_hex())),
        ("change_id", json::s(&c.change_id.to_hex())),
        ("author", json::s(&author_name(repo, c))),
        ("author_key", json::s(&c.author.to_hex())),
        ("when_ms", json::n(c.hlc.wall_ms)),
        ("message", json::s(&c.message)),
        ("kind", json::s(&format!("{:?}", c.kind).to_lowercase())),
        ("deps", json::hashes(&c.deps)),
        ("head", json::b(e.is_head)),
        ("working_copy", json::b(e.is_working_copy)),
        (
            "signature",
            if e.is_working_copy {
                "null".into()
            } else {
                signature_json(repo, &e.hash)?
            },
        ),
    ]))
}

/// `START,END:PATH` for `oxy log -L`.
fn parse_line_range(spec: &str) -> Result<(usize, usize, &str)> {
    let bad = || anyhow::anyhow!("-L {spec}: expected START,END:PATH, as 10,24:src/lib.rs");
    let (range, path) = spec.split_once(':').ok_or_else(bad)?;
    let (a, b) = range.split_once(',').ok_or_else(bad)?;
    Ok((
        a.trim().parse().map_err(|_| bad())?,
        b.trim().parse().map_err(|_| bad())?,
        path,
    ))
}

pub fn log(
    limit: Option<usize>,
    verbose: bool,
    path: Option<&str>,
    lines: Option<&str>,
    as_json: bool,
) -> Result<i32> {
    let repo = open()?;
    // Whether the working copy is clean and conflicted: from the manifest
    // when it proves the working copy clean, else from a snapshot.
    let (conflicted, clean) = if repo.clean_by_manifest()? {
        (false, true)
    } else {
        let snap = repo.snapshot_status("oxy log")?;
        (snap.base_snapshot.is_conflicted(), snap.statuses.is_empty())
    };
    let entries = match (path, lines) {
        (_, Some(spec)) => {
            let (first, last, p) = parse_line_range(spec)?;
            let (_, wc) = repo.working_copy()?;
            let base = repo.load_state_history(&wc.deps)?.maximal(&wc.deps);
            repo.line_history(&base, p, first, last)?
        }
        (Some(p), None) => repo.log_for_path(p)?,
        (None, None) => repo.log()?,
    };
    if as_json {
        let shown = limit.unwrap_or(entries.len()).min(entries.len());
        let mut items = Vec::new();
        for e in entries.iter().take(shown) {
            items.push(log_entry_json(&repo, e)?);
        }
        println!(
            "{}",
            json::obj([
                ("bookmark", json::s(&repo.config.bookmark)),
                ("total", json::n(entries.len())),
                ("changes", json::arr(items))
            ])
        );
        return Ok(0);
    }
    let total = entries.len();
    let shown = limit.unwrap_or(total).min(total);
    let rail = ui::rail();
    for (i, e) in entries.iter().take(shown).enumerate() {
        let c = &e.change;
        let bullet = ui::log_bullet(
            e.is_working_copy,
            e.is_head,
            e.is_working_copy && conflicted,
        );
        let mut labels = Vec::new();
        if e.is_working_copy {
            labels.push(ui::warn("working copy"));
        }
        if c.kind == ChangeKind::Resolution {
            labels.push(ui::warn("resolution"));
        }
        let labels = if labels.is_empty() {
            String::new()
        } else {
            format!(
                " {}{}{}",
                ui::dim("("),
                labels.join(ui::dim(", ").as_str()),
                ui::dim(")")
            )
        };
        let subject = if e.is_working_copy && c.message.is_empty() {
            ui::dim(if clean {
                "(clean)"
            } else {
                "(uncommitted changes)"
            })
        } else {
            ui::subject(subject_of(&c.message))
        };
        println!("{bullet} {}{labels}  {subject}", ui::id(short_meta_id(c)));
        let meta = format!(
            "{}{}{}{}{}{}{}",
            ui::hash(format!("#{}", e.hash.short(12))),
            ui::sep(),
            ui::author(author_name(&repo, c)),
            ui::sep(),
            ui::dim(ui::ago(c.hlc.wall_ms)),
            ui::sep(),
            if e.is_working_copy {
                ui::dim("not yet committed")
            } else {
                signature_mark(&repo, &e.hash)?
            }
        );
        println!("{rail} {meta}");
        if verbose {
            if !e.is_working_copy {
                println!(
                    "{rail} {}",
                    ui::dim(format!(
                        "{} {}",
                        when(c.hlc.wall_ms),
                        signature_line(&repo, &e.hash)?
                    ))
                );
            }
            if !c.deps.is_empty() {
                println!(
                    "{rail} {} {}",
                    ui::dim(ui::glyph("↳", "->")),
                    ui::dim(deps_of(&c.deps))
                );
            }
            let body: Vec<&str> = c
                .message
                .lines()
                .skip(1)
                .skip_while(|l| l.trim().is_empty())
                .collect();
            if !body.is_empty() {
                println!("{rail}");
                for line in body {
                    println!("{rail}   {line}");
                }
            }
        }
        if i + 1 < shown {
            println!("{rail}");
        }
    }
    if shown < total {
        println!(
            "{}",
            ui::dim(format!(
                "{} {} more; pass -n to see them",
                ui::glyph("…", "..."),
                total - shown
            ))
        );
    }
    Ok(0)
}

pub fn diff(change: Option<&str>, as_json: bool) -> Result<i32> {
    let repo = open()?;
    let hash = change.map(|c| repo.resolve_change(c)).transpose()?;
    if as_json {
        let files = repo.diff_files(hash.as_ref())?;
        let items = files.iter().map(|f| {
            json::obj([
                ("path", json::s(&f.path)),
                ("kind", json::s(&f.kind)),
                ("from", json::opt(f.from.as_deref(), json::s)),
                (
                    "hunks",
                    json::arr(f.hunks.iter().map(|h| {
                        json::obj([
                            ("base_line", json::n(h.base_line)),
                            (
                                "added",
                                json::arr(
                                    h.added.iter().map(|l| json::s(&String::from_utf8_lossy(l))),
                                ),
                            ),
                            (
                                "removed",
                                json::arr(h.removed.iter().map(|(n, l)| {
                                    json::obj([
                                        ("line", json::n(*n)),
                                        ("text", json::s(&String::from_utf8_lossy(l))),
                                    ])
                                })),
                            ),
                        ])
                    })),
                ),
            ])
        });
        println!(
            "{}",
            json::obj([
                ("change", json::opt(hash, |h| json::s(&h.to_hex()))),
                ("files", json::arr(items))
            ])
        );
        return Ok(0);
    }
    match hash {
        Some(h) => {
            let c = repo.store().get_change(&h)?;
            let (base, snapshot) = repo.change_base(&c)?;
            print!("{}", render_change(&c, &base, &snapshot));
        }
        None => {
            let snap = repo.snapshot_status("oxy diff")?;
            print!(
                "{}",
                render_change(&snap.wc, &snap.base, &snap.base_snapshot)
            );
        }
    }
    Ok(0)
}

pub fn cat(path: &str, change: Option<&str>) -> Result<i32> {
    let repo = open()?;
    let heads = change.map(|c| repo.resolve_heads(c)).transpose()?;
    let bytes = repo.file_at(path, heads.as_deref())?;
    use std::io::Write as _;
    std::io::stdout().write_all(&bytes)?;
    Ok(0)
}

pub fn root(as_json: bool) -> Result<i32> {
    let Ok(repo) = Repo::open(&std::env::current_dir()?) else {
        if as_json {
            println!("null");
        }
        return Ok(1);
    };
    if as_json {
        println!(
            "{}",
            json::obj([
                ("root", json::s(&repo.root().to_string_lossy())),
                ("workspace", json::s(&repo.workspace().to_hex())),
                ("bookmark", json::s(&repo.config.bookmark))
            ])
        );
    } else {
        println!("{}", repo.root().display());
    }
    Ok(0)
}

pub fn version(as_json: bool) -> Result<i32> {
    if as_json {
        println!(
            "{}",
            json::obj([
                ("version", json::s(env!("CARGO_PKG_VERSION"))),
                ("protocol", json::n(oxy_core::protocol::PROTOCOL_VERSION)),
                ("format", json::n(2))
            ])
        );
    } else {
        println!(
            "oxy {} (repository format 2, protocol {})",
            env!("CARGO_PKG_VERSION"),
            oxy_core::protocol::PROTOCOL_VERSION
        );
    }
    Ok(0)
}

pub fn discard(paths: &[String], hunks: &[usize]) -> Result<i32> {
    let repo = open()?;
    if paths.is_empty() && hunks.is_empty() {
        anyhow::bail!("name paths to restore, or --hunks to undo chosen hunks");
    }
    let mut n = 0;
    if !hunks.is_empty() {
        n += repo.discard_hunks(hunks)?;
    }
    if !paths.is_empty() {
        n += repo.discard(paths)?;
    }
    println!(
        "{} {} restored to the working copy's base",
        ui::done("Discarded"),
        plural(n, "path")
    );
    Ok(0)
}

pub fn hunks(as_json: bool) -> Result<i32> {
    let repo = open()?;
    let (_, hunks) = repo.hunks()?;
    if as_json {
        println!(
            "{}",
            json::arr(hunks.iter().map(|h| json::obj([
                ("index", json::n(h.index)),
                ("path", json::s(&h.path)),
                ("text", json::s(&h.text))
            ])))
        );
        return Ok(0);
    }
    if hunks.is_empty() {
        println!(
            "{}",
            ui::dim("No hunks: the working copy matches its base.")
        );
    }
    for h in &hunks {
        println!(
            "{} {}",
            ui::section(format!("hunk {}", h.index)),
            ui::path(&h.path)
        );
        for line in h.text.lines() {
            let styled = if line.starts_with('+') {
                ui::ok(line)
            } else if line.starts_with('-') {
                ui::err(line)
            } else {
                ui::dim(line)
            };
            println!("  {styled}");
        }
    }
    Ok(0)
}

pub fn show(change: &str, as_json: bool) -> Result<i32> {
    let repo = open()?;
    repo.snapshot_status("oxy show")?;
    let h = repo.resolve_change(change)?;
    let c = repo.store().get_change(&h)?;
    if as_json {
        let files = repo.diff_files(Some(&h))?;
        let heads = repo.bookmark_heads()?;
        let entry = oxy_core::repo::LogEntry {
            hash: h,
            change: oxy_core::state::ChangeMeta::of(&c),
            is_working_copy: c.kind == oxy_core::objects::ChangeKind::WorkingCopy,
            is_head: heads.contains(&h),
        };
        let mut body = log_entry_json(&repo, &entry)?;
        body.pop();
        body.push_str(&format!(
            ",{}:{}}}",
            json::s("files"),
            json::arr(files.iter().map(|f| json::obj([
                ("path", json::s(&f.path)),
                ("kind", json::s(&f.kind)),
                ("from", json::opt(f.from.as_deref(), json::s))
            ])))
        ));
        println!("{body}");
        return Ok(0);
    }
    println!(
        "{} {} {}",
        ui::section("change"),
        ui::id(short_id(&c)),
        ui::hash(format!("#{h}"))
    );
    println!("{}", ui::kv("kind", format!("{:?}", c.kind).to_lowercase()));
    println!(
        "{}",
        ui::kv(
            "author",
            ui::author(author_name(&repo, &oxy_core::state::ChangeMeta::of(&c)))
        )
    );
    println!(
        "{}",
        ui::kv(
            "date",
            format!(
                "{} {}",
                when(c.hlc.wall_ms),
                ui::dim(format!("({})", ui::ago(c.hlc.wall_ms)))
            )
        )
    );
    println!("{}", ui::kv("deps", ui::dim(deps_line(&c))));
    println!("{}", ui::kv("sig", signature_line(&repo, &h)?));
    println!();
    for line in (if c.message.is_empty() {
        "(no description)"
    } else {
        &c.message
    })
    .lines()
    {
        println!("    {line}");
    }
    println!();
    print!("{}", repo.describe_change(&h)?);
    Ok(0)
}

pub fn checkout(changes: &[String], discard: bool, carry: bool) -> Result<i32> {
    let repo = open()?;
    let heads = if changes.is_empty() {
        repo.bookmark_heads()?
    } else {
        let mut heads = Vec::new();
        for c in changes {
            heads.extend(repo.resolve_heads(c)?);
        }
        heads
    };
    let spec = if changes.is_empty() {
        repo.config.bookmark.clone()
    } else {
        changes.join(" ")
    };
    let sp = ui::spinner(&format!("Checking out {spec}…"));
    let command = format!("oxy checkout {spec}");
    let (r, carried) = if carry {
        repo.checkout_carry(&heads, &spec, &command)?
    } else {
        (repo.checkout(&heads, discard, &command)?, vec![])
    };
    sp.done(&format!(
        "{} on {}: {} written, {} removed{}",
        ui::done("Working copy"),
        ui::bookmark(&spec),
        plural(r.written, "file"),
        r.removed,
        if carried.is_empty() {
            String::new()
        } else {
            format!("; carried {}", plural(carried.len(), "changed path"))
        }
    ));
    for n in &r.notes {
        println!("  {} {n}", ui::note());
    }
    if r.conflicted {
        println!(
            "  {} {}",
            ui::caution(),
            ui::warn("this state has conflicts; see oxy status")
        );
    }
    Ok(0)
}

pub fn resolve(as_json: bool) -> Result<i32> {
    let repo = open()?;
    let snap = repo.snapshot("oxy resolve")?;
    if as_json {
        println!("{}", repo.status_json(&snap)?);
        return Ok(if snap.base_snapshot.is_conflicted() {
            2
        } else {
            0
        });
    }
    if !snap.base_snapshot.is_conflicted() {
        println!("The working copy's base has no conflicts.");
        return Ok(0);
    }
    let mut remaining = 0;
    for (p, f) in &snap.base_snapshot.files {
        if !f.is_conflicted() {
            continue;
        }
        match snap
            .statuses
            .iter()
            .find(|s| s.path == *p)
            .map(|s| s.status)
        {
            Some(ChangeStatus::Resolved) => println!("resolved   {p}"),
            Some(ChangeStatus::ConflictEdited) => {
                remaining += 1;
                println!("markers    {p}");
            }
            _ => {
                remaining += 1;
                println!("unresolved {p}");
            }
        }
    }
    for c in &snap.base_snapshot.tree.conflicts {
        remaining += 1;
        println!("tree       {c:?}");
    }
    if remaining == 0 {
        println!("All conflicts are resolved; `oxy commit` will record the resolution.");
        Ok(0)
    } else {
        Ok(2)
    }
}

pub fn undo() -> Result<i32> {
    let repo = open()?;
    let op = repo.undo()?;
    println!("{} now at: {}", ui::done("Undone;"), ui::dim(&op.command));
    Ok(0)
}

pub fn op_log(as_json: bool) -> Result<i32> {
    let repo = open()?;
    if as_json {
        let ops = repo.op_log()?;
        println!(
            "{}",
            json::arr(ops.iter().enumerate().map(|(i, (r, op))| {
                json::obj([
                    ("id", json::s(&r.to_hex())),
                    ("when_ms", json::n(op.hlc.wall_ms)),
                    ("command", json::s(&op.command)),
                    ("snapshot", json::b(op.command.ends_with("(snapshot)"))),
                    ("current", json::b(i == 0)),
                ])
            }))
        );
        return Ok(0);
    }
    for (i, (r, op)) in repo.op_log()?.into_iter().enumerate() {
        let bullet = if i == 0 {
            ui::ok(ui::glyph("●", "@"))
        } else {
            ui::dim(ui::glyph("○", "o"))
        };
        let cmd = subject_of(&op.command).split("\\n").next().unwrap_or("");
        println!(
            "{bullet} {}{}{}  {}",
            ui::hash(r.short(12)),
            ui::sep(),
            ui::dim(format!("{:<16}", ui::ago(op.hlc.wall_ms))),
            if i == 0 {
                ui::subject(cmd)
            } else {
                cmd.to_string()
            }
        );
    }
    Ok(0)
}

pub fn gc(now: bool) -> Result<i32> {
    let repo = open()?;
    let sp = ui::spinner("Packing and pruning…");
    let r = repo.gc_with(now, &mut |phase| sp.set(&format!("{phase}…")))?;
    sp.clear();
    if r.packed.objects > 0 {
        println!(
            "Packed {} into one pack: {} bytes -> {} bytes ({:.0}%).",
            plural(r.packed.objects, "object"),
            r.packed.raw_bytes,
            r.packed.packed_bytes,
            100.0 * r.packed.packed_bytes as f64 / r.packed.raw_bytes.max(1) as f64
        );
    }
    println!(
        "{} reachable; pruned {} ({} bytes){}{}; {} present.",
        plural(r.reachable, "object"),
        plural(r.pruned.objects, "unreachable object"),
        r.pruned.bytes,
        if r.pruned.deferred > 0 {
            format!(
                "; {} deferred by the grace period (use --now)",
                plural(r.pruned.deferred, "object")
            )
        } else {
            String::new()
        },
        if r.merged_packs > 0 {
            format!("; merged {} into one", plural(r.merged_packs, "pack"))
        } else {
            String::new()
        },
        plural(repo.store().pack_count(), "pack")
    );
    Ok(0)
}

/// `oxy doctor`: exit 1 when a check fails, 0 otherwise (warnings allowed).
pub fn doctor(offline: bool, as_json: bool) -> Result<i32> {
    use oxy_core::repo::Health;
    let repo = open()?;
    let sp = ui::spinner(if offline {
        "Checking…"
    } else {
        "Checking, and contacting remotes…"
    });
    let r = repo.doctor(!offline);
    sp.clear();
    let code = if r.worst() == Health::Fail { 1 } else { 0 };
    let word = |h: Health| match h {
        Health::Ok => "ok",
        Health::Warn => "warning",
        Health::Fail => "fail",
    };
    if as_json {
        let checks: Vec<String> = r
            .checks
            .iter()
            .map(|c| {
                json::obj([
                    ("area", json::s(&c.area)),
                    ("health", json::s(word(c.health))),
                    ("message", json::s(&c.message)),
                    ("hint", json::opt(c.hint.as_deref(), json::s)),
                ])
            })
            .collect();
        println!(
            "{}",
            json::obj([("ok", json::b(code == 0)), ("checks", json::arr(checks))])
        );
        return Ok(code);
    }
    let mut last = "";
    for c in &r.checks {
        if c.area != last {
            println!("{}", ui::section(&c.area));
            last = &c.area;
        }
        let mark = match c.health {
            Health::Ok => ui::ok(ui::glyph("✔", "v")),
            Health::Warn => ui::caution(),
            Health::Fail => ui::err(ui::glyph("✖", "x")),
        };
        println!("  {mark} {}", c.message);
        if let Some(h) = &c.hint {
            println!("    {} {}", ui::dim("→"), ui::dim(h));
        }
    }
    let fails = r.checks.iter().filter(|c| c.health == Health::Fail).count();
    let warns = r.checks.iter().filter(|c| c.health == Health::Warn).count();
    if fails + warns == 0 {
        println!("{}", ui::done("Everything looks right."));
    } else {
        println!(
            "{} {}, {}.",
            if fails > 0 {
                ui::err(ui::glyph("✖", "x"))
            } else {
                ui::caution()
            },
            plural(fails, "problem"),
            plural(warns, "warning")
        );
    }
    Ok(code)
}

/// `oxy fsck`: exit 0 when sound (warnings allowed), 1 on any error.
pub fn fsck(as_json: bool) -> Result<i32> {
    use oxy_core::repo::Severity;
    let repo = open()?;
    let sp = ui::spinner("Checking every object…");
    let r = repo.fsck()?;
    sp.clear();
    let code = if r.errors() > 0 { 1 } else { 0 };
    if as_json {
        let problems: Vec<String> = r
            .problems
            .iter()
            .map(|p| {
                json::obj([
                    (
                        "severity",
                        json::s(match p.severity {
                            Severity::Error => "error",
                            Severity::Warning => "warning",
                        }),
                    ),
                    (
                        "object",
                        json::opt(p.object.map(|o| o.to_hex()).as_deref(), json::s),
                    ),
                    ("what", json::s(&p.what)),
                ])
            })
            .collect();
        println!(
            "{}",
            json::obj([
                ("ok", json::b(code == 0)),
                ("objects", json::n(r.objects)),
                ("ops", json::n(r.ops)),
                ("changes", json::n(r.changes)),
                ("signed", json::n(r.signed)),
                ("unsigned", json::n(r.unsigned)),
                ("checkpoints", json::n(r.checkpoints)),
                ("attestations", json::n(r.attestations)),
                ("errors", json::n(r.errors())),
                ("warnings", json::n(r.warnings())),
                ("problems", json::arr(problems)),
            ])
        );
        return Ok(code);
    }
    println!(
        "Checked {}, {}, {} ({} signed or sealed, {} unsigned), {}, {}.",
        plural(r.objects, "object"),
        plural(r.ops, "operation"),
        plural(r.changes, "change"),
        r.signed,
        r.unsigned,
        plural(r.checkpoints, "checkpoint"),
        plural(r.attestations, "attestation"),
    );
    for p in &r.problems {
        let obj = p
            .object
            .map(|o| format!("{} ", ui::hash(format!("#{}", o.short(12)))))
            .unwrap_or_default();
        match p.severity {
            Severity::Error => println!("{} {obj}{}", ui::err(ui::glyph("✖", "x")), p.what),
            Severity::Warning => println!("{} {obj}{}", ui::caution(), p.what),
        }
    }
    if r.problems.is_empty() {
        println!("{}", ui::done("No problems found."));
    } else if code == 0 {
        println!(
            "{}",
            ui::done(format!("Sound, with {}.", plural(r.warnings(), "warning")))
        );
    } else {
        println!(
            "{} {} and {}. Fetch missing objects from a remote with `oxy pull`, or clone afresh and compare.",
            ui::err(ui::glyph("✖", "x")),
            plural(r.errors(), "error"),
            plural(r.warnings(), "warning")
        );
    }
    Ok(code)
}

/// The head the working copy sits on, for commands that default to it. With
/// several heads beneath the working copy, the most recently made one is
/// chosen and announced.
fn current_head(repo: &Repo) -> Result<oxy_core::hash::ChangeHash> {
    let snap = repo.snapshot_status("oxy")?;
    let base = snap.base.maximal(&snap.wc.deps);
    match base.as_slice() {
        [] => anyhow::bail!("the working copy sits on no change yet"),
        [h] => Ok(*h),
        many => {
            let latest = many
                .iter()
                .max_by_key(|h| snap.base.get(h).map(|c| (c.hlc, **h)))
                .copied()
                .unwrap();
            let c = repo.store().get_change(&latest)?;
            println!(
                "Defaulting to {} #{} (most recent of the {} heads under the working copy)",
                short_id(&c),
                latest.short(12),
                many.len()
            );
            Ok(latest)
        }
    }
}

/// `oxy describe` without -m: the working copy's name for a build.
pub fn describe_name(as_json: bool) -> Result<i32> {
    let repo = open()?;
    let d = repo.describe_working_copy()?;
    if as_json {
        println!(
            "{}",
            json::obj([
                ("describe", json::s(&d.line())),
                ("tag", json::opt(d.tag.as_ref(), |t| json::s(t))),
                ("distance", json::n(d.distance)),
                ("bookmark", json::s(&d.bookmark)),
                ("change", json::s(&d.change.to_hex())),
                ("hash", json::s(&d.hash.to_hex())),
                ("dirty", json::b(d.dirty)),
            ])
        );
    } else {
        println!("{}", d.line());
    }
    Ok(0)
}

pub fn describe(message: &str, change: Option<&str>) -> Result<i32> {
    let repo = open()?;
    let h = match change {
        Some(c) => repo.resolve_change(c)?,
        None => current_head(&repo)?,
    };
    let new = repo.describe(&h, message)?;
    let c = repo.store().get_change(&new)?;
    println!(
        "{} {} {}  {}",
        ui::done("Described"),
        ui::id(short_id(&c)),
        ui::hash(format!("#{}", new.short(12))),
        ui::subject(subject_of(message))
    );
    Ok(0)
}

pub fn amend(message: Option<&str>, into: Option<&str>) -> Result<i32> {
    let repo = open()?;
    let new = match into {
        Some(spec) => {
            let target = repo.resolve_change(spec)?;
            repo.amend_into(&target, message)?
        }
        None => repo.amend(message)?,
    };
    let c = repo.store().get_change(&new)?;
    println!(
        "{} {} {}  {}",
        ui::done("Amended"),
        ui::id(short_id(&c)),
        ui::hash(format!("#{}", new.short(12))),
        ui::subject(subject_of(&c.message))
    );
    Ok(0)
}

pub fn abandon(change: &str) -> Result<i32> {
    let repo = open()?;
    let h = repo.resolve_change(change)?;
    let c = repo.store().get_change(&h)?;
    let notes = repo.abandon(&h)?;
    println!(
        "{} {} {}  {}",
        ui::done("Abandoned"),
        ui::id(short_id(&c)),
        ui::hash(format!("#{}", h.short(12))),
        ui::dim("its content remains on disk as uncommitted work if the working copy sat on it")
    );
    for n in notes {
        println!("  {} {n}", ui::note());
    }
    Ok(0)
}

pub fn checkpoint() -> Result<i32> {
    let repo = open()?;
    let sp = ui::spinner("Writing checkpoint…");
    let (r, changes, bytes) = repo.checkpoint()?;
    sp.done(&format!(
        "{} {} of {} ({} bytes) for {}",
        ui::done("Checkpoint"),
        ui::hash(format!("#{}", r.short(12))),
        plural(changes, "change"),
        bytes,
        ui::id(&repo.config.bookmark)
    ));
    Ok(0)
}

/// For shell prompts: silent (exit 1) outside a repository, otherwise one line.
pub fn prompt(format: &str, glyphs: bool, color: Option<&str>) -> Result<i32> {
    let Ok(repo) = Repo::open(&std::env::current_dir()?) else {
        return Ok(1);
    };
    let info = repo.quick_status()?;
    let fmt = if glyphs && format == oxy_core::repo::DEFAULT_PROMPT_FORMAT {
        oxy_core::repo::GLYPH_PROMPT_FORMAT
    } else {
        format
    };
    let line = match color {
        Some("bash") => info.format_colored(fmt, ("\\[", "\\]")),
        Some("zsh") => info.format_colored(fmt, ("%{", "%}")),
        Some(_) => info.format_colored(fmt, ("", "")),
        None => info.format(fmt),
    };
    println!("{line}");
    Ok(0)
}

pub fn sparse(paths: &[String]) -> Result<i32> {
    let mut repo = open()?;
    if paths.is_empty() {
        if repo.config.sparse_paths.is_empty() {
            println!("No sparse filter: the whole tree is materialized.");
        } else {
            println!("{}", ui::heading("Sparse filter"));
            for p in &repo.config.sparse_paths {
                println!("  {}", ui::path(p));
            }
        }
        return Ok(0);
    }
    let snap = repo.snapshot("oxy sparse")?;
    if !snap.wc.tree_ops.is_empty() || !snap.wc.edits.is_empty() {
        anyhow::bail!(
            "the working copy has changes; commit them before changing the sparse filter"
        );
    }
    repo.config.set("filter.paths", &paths.join(","))?;
    repo.save_config()?;
    let heads = repo.bookmark_heads()?;
    let sp = ui::spinner("Re-checking out with the new filter…");
    let r = repo.checkout(&heads, true, "oxy sparse (checkout)")?;
    sp.done(&format!(
        "{} {}: {} written, {} removed",
        ui::ok("Sparse filter set to"),
        ui::path(paths.join(",")),
        plural(r.written, "file"),
        r.removed
    ));
    Ok(0)
}

pub fn tag_create(name: &str, changes: &[String], message: &str) -> Result<i32> {
    let repo = open()?;
    repo.snapshot_status("oxy tag")?;
    let heads = if changes.is_empty() {
        repo.bookmark_heads()?
    } else {
        let mut heads = Vec::new();
        for c in changes {
            heads.extend(repo.resolve_heads(c)?);
        }
        heads
    };
    let t = repo.tag_create(name, &heads, message)?;
    println!(
        "{} {} {} {} ({}){}",
        ui::done("Tagged"),
        ui::bookmark(&t.name),
        ui::dim(ui::glyph("→", "->")),
        ui::hash(format!("#{}", t.state.short(12))),
        plural(t.heads.len(), "head"),
        t.signer
            .map(|s| format!(", signed by {s}"))
            .unwrap_or_else(|| ui::dim(", unsigned"))
    );
    Ok(0)
}

pub fn tag_list(as_json: bool) -> Result<i32> {
    let repo = open()?;
    let tags = repo.tags()?;
    if as_json {
        println!(
            "{}",
            json::arr(tags.iter().map(|t| {
                json::obj([
                    ("name", json::s(&t.name)),
                    ("state", json::s(&t.state.to_hex())),
                    ("heads", json::hashes(&t.heads)),
                    ("message", json::s(&t.message)),
                    (
                        "signer",
                        json::opt(t.signer.as_ref(), |s| json::s(&s.to_string())),
                    ),
                ])
            }))
        );
        return Ok(0);
    }
    if tags.is_empty() {
        println!("{}", ui::dim("No tags."));
    }
    for t in tags {
        println!(
            "{} {} {}{}{}{}",
            ui::ok(ui::glyph("⚑", "#")),
            ui::bookmark(&t.name),
            // The heads, as `oxy log` shows changes, not the state hash.
            ui::hash(
                t.heads
                    .iter()
                    .map(|h| format!("#{}", h.short(12)))
                    .collect::<Vec<_>>()
                    .join(" ")
            ),
            ui::sep() + &ui::dim(plural(t.heads.len(), "head")),
            if t.message.is_empty() {
                String::new()
            } else {
                format!("  {}", ui::subject(subject_of(&t.message)))
            },
            t.signer
                .map(|s| ui::sep() + &ui::ok(format!("{} {s}", ui::glyph("✔", "v"))))
                .unwrap_or_default()
        );
    }
    Ok(0)
}

pub fn workspace_add(path: &std::path::Path, changes: &[String]) -> Result<i32> {
    let repo = open()?;
    let heads = if changes.is_empty() {
        None
    } else {
        let mut heads = Vec::new();
        for c in changes {
            heads.extend(repo.resolve_heads(c)?);
        }
        Some(heads)
    };
    let sp = ui::spinner(&format!("Creating workspace at {}…", path.display()));
    let ws = repo.workspace_add(path, heads.as_deref())?;
    sp.done(&format!(
        "{} {} (workspace {})",
        ui::done("Workspace created at"),
        ui::path(ws.root().display()),
        ui::id(ws.workspace().short(8))
    ));
    Ok(0)
}

pub fn workspace_list(as_json: bool) -> Result<i32> {
    let repo = open()?;
    if as_json {
        println!(
            "{}",
            json::arr(repo.workspaces()?.iter().map(|w| {
                json::obj([
                    ("id", json::s(&w.id.to_hex())),
                    ("path", json::s(&w.path.to_string_lossy())),
                    ("current", json::b(w.current)),
                    (
                        "working_copy",
                        json::opt(w.working_copy, |h| json::s(&h.to_hex())),
                    ),
                ])
            }))
        );
        return Ok(0);
    }
    for w in repo.workspaces()? {
        println!(
            "{} {} {}{}",
            if w.current {
                ui::ok(ui::glyph("●", "*"))
            } else {
                ui::dim(ui::glyph("○", "o"))
            },
            ui::id(w.id.short(8)),
            ui::path(w.path.display()),
            w.working_copy
                .map(|h| ui::sep() + &ui::dim(format!("working copy #{}", h.short(12))))
                .unwrap_or_else(|| ui::sep() + &ui::warn("not in view"))
        );
    }
    Ok(0)
}

pub fn workspace_forget(spec: &str) -> Result<i32> {
    let repo = open()?;
    let all = repo.workspaces()?;
    let target = std::fs::canonicalize(spec).ok();
    let matches: Vec<_> = all
        .iter()
        .filter(|w| w.id.starts_with_hex(spec) || target.as_ref().is_some_and(|t| *t == w.path))
        .collect();
    let w = match matches.as_slice() {
        [w] => *w,
        [] => anyhow::bail!("no workspace matches {spec:?}"),
        _ => anyhow::bail!("{spec:?} is ambiguous"),
    };
    repo.workspace_forget(&w.id)?;
    println!(
        "{} workspace {} at {}; its files were left in place.",
        ui::done("Forgot"),
        ui::id(w.id.short(8)),
        ui::path(w.path.display())
    );
    Ok(0)
}

pub fn lock(path: &str) -> Result<i32> {
    let repo = open()?;
    repo.lock_path(path)?;
    println!(
        "{} {} {}",
        ui::done("Locked"),
        ui::path(path),
        ui::dim("(advisory, local)")
    );
    Ok(0)
}

pub fn unlock(path: &str) -> Result<i32> {
    let repo = open()?;
    repo.unlock_path(path)?;
    println!("{} {}", ui::done("Unlocked"), ui::path(path));
    Ok(0)
}

pub fn split(change: &str, paths: &[String]) -> Result<i32> {
    let repo = open()?;
    let h = repo.resolve_change(change)?;
    let (h1, h2) = repo.split(&h, paths)?;
    let c1 = repo.store().get_change(&h1)?;
    let c2 = repo.store().get_change(&h2)?;
    println!(
        "{} into {} {} and {} {}",
        ui::done("Split"),
        ui::id(short_id(&c1)),
        ui::hash(format!("#{}", h1.short(12))),
        ui::id(short_id(&c2)),
        ui::hash(format!("#{}", h2.short(12)))
    );
    Ok(0)
}

fn heads_from(repo: &Repo, changes: &[String]) -> Result<Vec<oxy_core::hash::ChangeHash>> {
    let mut heads = Vec::new();
    for c in changes {
        heads.extend(repo.resolve_heads(c)?);
    }
    Ok(heads)
}

pub fn bookmark_create(name: &str, changes: &[String], upto: bool, only: bool) -> Result<i32> {
    let repo = open()?;
    repo.snapshot_status("oxy bookmark create")?;
    let heads = if changes.is_empty() {
        None
    } else {
        let named = heads_from(&repo, changes)?;
        let (_, wc) = repo.working_copy()?;
        let gap = repo.state_gap(&wc.deps, &named)?;
        if upto {
            Some(gap.upto)
        } else if only || gap.earlier.is_empty() {
            Some(named)
        } else {
            anyhow::bail!(
                "{name} at {} would lack {} of the current state recorded before it:\n{}\n\
                 A state is its heads and what they depend on, not everything recorded before them.\n\
                 Pass --upto for everything of the current state up to {0} (as a Git branch would hold),\n\
                 or --only for just {0} and what it depends on.",
                changes.join(" "),
                plural(gap.earlier.len(), "change"),
                listed_changes(&repo, &gap.earlier)
            );
        }
    };
    let heads = repo.bookmark_create(name, heads.as_deref())?;
    println!(
        "{} bookmark {} {} {}",
        ui::done("Created"),
        ui::bookmark(name),
        ui::dim(ui::glyph("→", "->")),
        ui::dim(plural(heads.len(), "head"))
    );
    println!(
        "  {} {}",
        ui::note(),
        ui::dim(format!("switch to it with oxy bookmark switch {name}"))
    );
    Ok(0)
}

/// Up to five changes, newest last, as `  #hash subject` lines.
fn listed_changes(repo: &Repo, changes: &[oxy_core::hash::ChangeHash]) -> String {
    let shown = changes.len().min(5);
    let mut lines: Vec<String> = changes[changes.len() - shown..]
        .iter()
        .map(|h| {
            let subject = repo
                .store()
                .get_change(h)
                .map(|c| subject_of(&c.message).to_string())
                .unwrap_or_default();
            format!("  #{} {subject}", h.short(12))
        })
        .collect();
    if changes.len() > shown {
        lines.insert(0, format!("  … and {} earlier", changes.len() - shown));
    }
    lines.join("\n")
}

pub fn bookmark_set(name: &str, changes: &[String]) -> Result<i32> {
    let repo = open()?;
    repo.snapshot_status("oxy bookmark set")?;
    let heads = heads_from(&repo, changes)?;
    let heads = repo.bookmark_set(name, &heads)?;
    println!(
        "{} bookmark {} {} {}",
        ui::done("Moved"),
        ui::bookmark(name),
        ui::dim(ui::glyph("→", "->")),
        ui::dim(plural(heads.len(), "head"))
    );
    Ok(0)
}

pub fn bookmark_delete(name: &str) -> Result<i32> {
    let repo = open()?;
    repo.bookmark_delete(name)?;
    println!(
        "{} bookmark {} {}",
        ui::done("Deleted"),
        ui::bookmark(name),
        ui::dim("(its changes stay until unreachable)")
    );
    Ok(0)
}

pub fn bookmark_list(as_json: bool) -> Result<i32> {
    let repo = open()?;
    if as_json {
        let items = repo.bookmarks()?.into_iter().map(|b| {
            json::obj([
                ("name", json::s(&b.name)),
                ("heads", json::hashes(&b.heads)),
                ("current", json::b(b.current)),
                ("ahead", json::opt(b.ahead, json::n)),
                ("behind", json::opt(b.behind, json::n)),
            ])
        });
        println!("{}", json::arr(items));
        return Ok(0);
    }
    for b in repo.bookmarks()? {
        let mark = if b.current {
            ui::ok(ui::glyph("●", "*"))
        } else {
            ui::dim(ui::glyph("○", "o"))
        };
        let mut tail = String::new();
        if let Some(n) = b.ahead.filter(|n| *n > 0) {
            tail += &ui::ok(format!(" {}{n}", ui::glyph("↑", "+")));
        }
        if let Some(n) = b.behind.filter(|n| *n > 0) {
            tail += &ui::warn(format!(" {}{n}", ui::glyph("↓", "-")));
        }
        let head = b
            .heads
            .first()
            .map(|h| {
                repo.store()
                    .get_change(h)
                    .map(|c| ui::subject(subject_of(&c.message)))
                    .unwrap_or_default()
            })
            .unwrap_or_else(|| ui::dim("(empty)"));
        println!(
            "{mark} {}{}{}{tail}  {head}",
            ui::bookmark(&b.name),
            ui::sep(),
            ui::dim(plural(b.heads.len(), "head"))
        );
    }
    Ok(0)
}

pub fn bookmark_switch(name: &str, discard: bool, carry: bool) -> Result<i32> {
    let mut repo = open()?;
    let from = repo.config.bookmark.clone();
    let before = repo
        .working_copy()
        .map(|(_, wc)| wc.deps)
        .unwrap_or_default();
    let sp = ui::spinner(&format!("Switching to {name}…"));
    let (r, carried) = if carry {
        repo.bookmark_switch_carry(name)?
    } else {
        (repo.bookmark_switch(name, discard)?, vec![])
    };
    sp.done(&format!(
        "{} to {}: {} written, {} removed{}",
        ui::done("Switched"),
        ui::bookmark(name),
        plural(r.written, "file"),
        r.removed,
        if carried.is_empty() {
            String::new()
        } else {
            format!("; carried {}", plural(carried.len(), "changed path"))
        }
    ));
    if r.conflicted {
        println!(
            "  {} {}",
            ui::caution(),
            ui::warn("this state has conflicts; see oxy status")
        );
    }
    // Say when the new state leaves out work the old one had: a state is
    // its heads and what they depend on, which can be far less than a Git
    // user expects.
    let after = repo
        .working_copy()
        .map(|(_, wc)| wc.deps)
        .unwrap_or_default();
    if let Ok(gap) = repo.state_gap(&before, &after) {
        if gap.lacks > 0 {
            println!(
                "  {} {}",
                ui::note(),
                ui::dim(format!(
                    "{name} lacks {} that {from} has",
                    plural(gap.lacks, "change")
                ))
            );
        }
    }
    Ok(0)
}

pub fn merge(bookmark: &str) -> Result<i32> {
    let repo = open()?;
    let sp = ui::spinner(&format!("Merging {bookmark}…"));
    let r = repo.merge(bookmark)?;
    if !r.changed {
        sp.done(&format!(
            "{} {}",
            ui::ok(ui::glyph("✔", "*")),
            ui::dim(format!(
                "{} already contains {bookmark}",
                repo.config.bookmark
            ))
        ));
        return Ok(0);
    }
    sp.done(&format!(
        "{} {} into {}: now {}{}",
        ui::done("Merged"),
        ui::bookmark(bookmark),
        ui::bookmark(&repo.config.bookmark),
        plural(r.heads.len(), "head"),
        ui::dim(if r.checked_out {
            "; working copy updated"
        } else {
            "; run oxy checkout to update the working copy"
        })
    ));
    let snap = repo.snapshot("oxy merge")?;
    if snap.base_snapshot.is_conflicted() {
        println!(
            "  {} {}",
            ui::caution(),
            ui::warn("the result has conflicts; see oxy status")
        );
    }
    Ok(0)
}

pub fn squash(change: &str, into: &str) -> Result<i32> {
    let repo = open()?;
    let c = repo.resolve_change(change)?;
    let d = repo.resolve_change(into)?;
    let sp = ui::spinner("Squashing…");
    let h = repo.squash(&c, &d)?;
    let new = repo.store().get_change(&h)?;
    sp.done(&format!(
        "{} into {} {}  {}",
        ui::done("Squashed"),
        ui::id(short_id(&new)),
        ui::hash(format!("#{}", h.short(12))),
        ui::subject(subject_of(&new.message))
    ));
    Ok(0)
}

pub fn rebase(change: &str, onto: &[String]) -> Result<i32> {
    let repo = open()?;
    let c = repo.resolve_change(change)?;
    let mut heads = Vec::new();
    for o in onto {
        heads.extend(repo.resolve_heads(o)?);
    }
    let sp = ui::spinner("Rebasing…");
    let h = repo.rebase(&c, &heads)?;
    let new = repo.store().get_change(&h)?;
    sp.done(&format!(
        "{} {} {}  {}",
        ui::done("Rebased"),
        ui::id(short_id(&new)),
        ui::hash(format!("#{}", h.short(12))),
        ui::dim(format!(
            "now depends on {}",
            plural(new.deps.len(), "change")
        ))
    ));
    Ok(0)
}