#![cfg(unix)]

use std::{
    collections::BTreeMap,
    ffi::OsString,
    fs,
    os::unix::{
        ffi::OsStringExt,
        fs::{PermissionsExt, symlink},
    },
    path::{Path, PathBuf},
    process::{Command, Output},
    sync::{
        Arc,
        atomic::{AtomicBool, AtomicU64, Ordering},
    },
};
use vamp::{
    diff::{Category, Comparison, ComparisonMode, FileStatus, RepoKind, Revision, RevisionTarget},
    repository::Repository,
};

static NEXT: AtomicU64 = AtomicU64::new(0);
struct Fixture(PathBuf);
impl Fixture {
    fn new() -> Self {
        let path = std::env::temp_dir().join(format!(
            "vamp-repository-test-{}-{}",
            std::process::id(),
            NEXT.fetch_add(1, Ordering::Relaxed)
        ));
        fs::create_dir(&path).unwrap();
        Self(path)
    }
    fn dir(&self, name: &str) -> PathBuf {
        let path = self.0.join(name);
        fs::create_dir(&path).unwrap();
        path
    }
}
impl Drop for Fixture {
    fn drop(&mut self) {
        let _ = fs::remove_dir_all(&self.0);
    }
}
fn command(program: &str, root: &Path, args: &[&str]) -> Output {
    Command::new(program)
        .current_dir(root)
        .args(args)
        .env("GIT_CONFIG_NOSYSTEM", "1")
        .env("GIT_CONFIG_GLOBAL", "/dev/null")
        .env("GIT_OPTIONAL_LOCKS", "0")
        .env("GIT_TERMINAL_PROMPT", "0")
        .env("GIT_AUTHOR_DATE", "2000-01-01T00:00:00Z")
        .env("GIT_COMMITTER_DATE", "2000-01-01T00:00:00Z")
        .env("JJ_CONFIG", "/dev/null")
        .env("JJ_USER", "Diff Test")
        .env("JJ_EMAIL", "diff@example.invalid")
        .output()
        .unwrap()
}
fn success(program: &str, root: &Path, args: &[&str]) -> String {
    let result = command(program, root, args);
    assert!(
        result.status.success(),
        "{program} {args:?}: {}",
        String::from_utf8_lossy(&result.stderr)
    );
    String::from_utf8(result.stdout)
        .unwrap()
        .trim_end_matches('\n')
        .into()
}
fn git(root: &Path, args: &[&str]) -> String {
    success("git", root, args)
}
fn jj(root: &Path, args: &[&str]) -> String {
    success("jj", root, args)
}
fn init_git(root: &Path) {
    git(root, &["init", "--initial-branch=local"]);
    git(root, &["config", "user.name", "Diff Test"]);
    git(root, &["config", "user.email", "diff@example.invalid"]);
}
fn init_jj(root: &Path, colocate: bool) {
    jj(
        root,
        &[
            "git",
            "init",
            if colocate {
                "--colocate"
            } else {
                "--no-colocate"
            },
        ],
    );
    jj(root, &["config", "set", "--repo", "user.name", "Diff Test"]);
    jj(
        root,
        &[
            "config",
            "set",
            "--repo",
            "user.email",
            "diff@example.invalid",
        ],
    );
}
fn open(root: &Path) -> Repository {
    Repository::open(root, Arc::new(AtomicBool::new(false))).unwrap()
}
fn revision(id: &str, kind: RepoKind) -> Revision {
    Revision {
        target: RevisionTarget::Commit(id.into()),
        label: id.into(),
        description: String::new(),
        category: if kind == RepoKind::Jujutsu {
            Category::Revisions
        } else {
            Category::Commits
        },
    }
}
fn working(kind: RepoKind) -> Revision {
    let mut r = revision("working", kind);
    r.target = RevisionTarget::Working;
    r
}

fn compare_loaded(
    repository: &mut Repository,
    before: &Revision,
    after: &Revision,
    buffers: &[(PathBuf, String)],
) -> Result<Comparison, String> {
    let mut comparison =
        repository.compare(1, before, after, ComparisonMode::Snapshots, buffers)?;
    for (index, file) in comparison.files.iter_mut().enumerate() {
        *file = repository.load_file(1, index)?;
        if file
            .notice
            .as_deref()
            .is_some_and(|notice| notice.contains("Binary or non-UTF-8"))
        {
            comparison.editable_paths.remove(&file.path);
        }
    }
    Ok(comparison)
}
fn changed<'a>(comparison: &'a Comparison, path: &Path) -> &'a vamp::diff::ChangedFile {
    comparison
        .files
        .iter()
        .find(|f| f.path == path)
        .unwrap_or_else(|| panic!("Missing changed file {path:?}: {:?}", comparison.files))
}
// Capture active metadata, checkout bytes, executable bits and link targets. Access
// times are intentionally excluded: reading a repository must not change its data.
fn disk_state(root: &Path) -> BTreeMap<PathBuf, (u32, Vec<u8>)> {
    fn visit(root: &Path, path: &Path, result: &mut BTreeMap<PathBuf, (u32, Vec<u8>)>) {
        for entry in fs::read_dir(path).unwrap() {
            let entry = entry.unwrap();
            let full = entry.path();
            let metadata = fs::symlink_metadata(&full).unwrap();
            if metadata.is_dir() {
                visit(root, &full, result);
            } else {
                let data = if metadata.file_type().is_symlink() {
                    use std::os::unix::ffi::OsStrExt;
                    fs::read_link(&full)
                        .unwrap()
                        .as_os_str()
                        .as_bytes()
                        .to_vec()
                } else {
                    fs::read(&full).unwrap()
                };
                result.insert(
                    full.strip_prefix(root).unwrap().to_path_buf(),
                    (metadata.permissions().mode(), data),
                );
            }
        }
    }
    let mut result = BTreeMap::new();
    visit(root, root, &mut result);
    result
}

#[test]
fn git_working_reads_disk_and_handles_ranges_ignored_files_binary_links_and_odd_paths() {
    let fixture = Fixture::new();
    let root = fixture.dir("git");
    init_git(&root);
    for (path, data) in [
        ("text", &b"one\nthree\n"[..]),
        ("removed", b"removed\n"),
        ("empty-before", b""),
        ("newline", b"same\n"),
        ("crlf", b"a\r\n"),
        ("rename-old", b"move\n"),
        ("binary", b"\0old"),
        ("ignored-tracked", b"old\n"),
        ("executable", b"script\n"),
        ("type-switch", b"target"),
        (".gitignore", b"ignored-*\n"),
    ] {
        fs::write(root.join(path), data).unwrap();
    }
    git(&root, &["add", "."]);
    git(&root, &["add", "--force", "ignored-tracked"]);
    git(&root, &["commit", "-m", "baseline"]);
    git(&root, &["tag", "-a", "annotated", "-m", "tag"]);
    git(
        &root,
        &["tag", "-a", "nested", "-m", "nested tag", "annotated"],
    );
    let id = git(&root, &["rev-parse", "HEAD"]);
    fs::write(root.join("text"), b"one\nstaged\nthree\n").unwrap();
    git(&root, &["add", "text"]);
    fs::write(root.join("text"), b"one\ntwo\nthree\n").unwrap();
    fs::remove_file(root.join("removed")).unwrap();
    fs::write(root.join("empty-before"), b"first\n").unwrap();
    fs::write(root.join("empty-added"), b"").unwrap();
    fs::write(root.join("added"), b"added\n").unwrap();
    fs::write(root.join("newline"), b"same").unwrap();
    fs::write(root.join("crlf"), b"b\r\n").unwrap();
    fs::write(root.join("binary"), b"\0new").unwrap();
    fs::write(root.join("ignored-tracked"), b"changed\n").unwrap();
    fs::write(root.join("ignored-untracked"), b"must not appear\n").unwrap();
    fs::rename(root.join("rename-old"), root.join("rename-new")).unwrap();
    fs::remove_file(root.join("type-switch")).unwrap();
    symlink("target", root.join("type-switch")).unwrap();
    fs::set_permissions(root.join("executable"), fs::Permissions::from_mode(0o755)).unwrap();
    let odd = PathBuf::from("-tab\tand\nnewline");
    fs::write(root.join(&odd), b"odd\n").unwrap();
    let non_utf8 = PathBuf::from(OsString::from_vec(b"non-utf8-\xff".to_vec()));
    let non_utf8_created = match fs::write(root.join(&non_utf8), b"bytes\n") {
        Ok(()) => true,
        // APFS rejects non-UTF-8 names before repository code can read them.
        Err(error) if cfg!(target_os = "macos") && error.raw_os_error() == Some(92) => false,
        Err(error) => panic!("Cannot create non-UTF-8 fixture: {error}"),
    };
    symlink("/not/a/path/to/read", root.join("link")).unwrap();
    let state = disk_state(&root);
    let mut repository = open(&root);
    let catalog = repository.catalog().unwrap();
    assert_eq!(catalog.kind, RepoKind::Git);
    assert_eq!(catalog.entries[0].target, RevisionTarget::Working);
    assert!(
        catalog
            .entries
            .iter()
            .any(|r| r.label == id && r.description == "baseline")
    );
    assert!(catalog.entries.iter().any(|r| r.label == "nested"
        && r.category == Category::Tags
        && r.target == RevisionTarget::Commit(id.clone())));
    let comparison = compare_loaded(
        &mut repository,
        &revision(&id, RepoKind::Git),
        &working(RepoKind::Git),
        &[],
    )
    .unwrap();
    let text = changed(&comparison, Path::new("text"));
    assert_eq!(comparison.root, fs::canonicalize(&root).unwrap());
    assert!(comparison.editable_paths.contains(Path::new("text")));
    assert!(comparison.editable_paths.contains(Path::new("empty-added")));
    for path in ["binary", "link", "removed", "type-switch"] {
        assert!(!comparison.editable_paths.contains(Path::new(path)));
    }
    assert_eq!(text.after, ["one", "two", "three"]);
    assert_eq!(
        (
            text.hunks[0].before_start,
            text.hunks[0].before_len,
            text.hunks[0].after_start,
            text.hunks[0].after_len
        ),
        (1, 0, 1, 1)
    );
    let empty = changed(&comparison, Path::new("empty-before"));
    assert_eq!(
        (
            empty.hunks[0].before_start,
            empty.hunks[0].before_len,
            empty.hunks[0].after_start,
            empty.hunks[0].after_len
        ),
        (0, 0, 0, 1)
    );
    let deleted = changed(&comparison, Path::new("removed"));
    assert_eq!(deleted.status, FileStatus::Removed);
    assert_eq!(
        (
            deleted.hunks[0].before_start,
            deleted.hunks[0].before_len,
            deleted.hunks[0].after_start,
            deleted.hunks[0].after_len
        ),
        (0, 1, 0, 0)
    );
    assert_eq!(
        changed(&comparison, Path::new("empty-added")).status,
        FileStatus::Added
    );
    assert!(
        changed(&comparison, Path::new("empty-added"))
            .after
            .is_empty()
    );
    assert_eq!(changed(&comparison, &odd).after, ["odd"]);
    if non_utf8_created {
        assert_eq!(changed(&comparison, &non_utf8).after, ["bytes"]);
    }
    assert_eq!(changed(&comparison, Path::new("crlf")).after, ["b\r"]);
    assert!(
        changed(&comparison, Path::new("newline"))
            .notice
            .as_ref()
            .unwrap()
            .contains("EOF newline")
    );
    let type_switch = changed(&comparison, Path::new("type-switch"));
    assert_eq!(type_switch.before, type_switch.after);
    assert!(
        type_switch
            .notice
            .as_ref()
            .unwrap()
            .contains("100644 → 120000")
    );
    let binary = changed(&comparison, Path::new("binary"));
    assert!(binary.before.is_empty() && binary.after.is_empty() && binary.hunks.is_empty());
    assert!(binary.notice.as_ref().unwrap().contains("Binary"));
    assert_eq!(
        changed(&comparison, Path::new("link")).after,
        ["/not/a/path/to/read"]
    );
    assert!(
        changed(&comparison, Path::new("link"))
            .notice
            .as_ref()
            .unwrap()
            .contains("Symbolic link")
    );
    assert!(
        changed(&comparison, Path::new("executable"))
            .notice
            .as_ref()
            .unwrap()
            .contains("mode changed")
    );
    assert_eq!(
        changed(&comparison, Path::new("ignored-tracked")).after,
        ["changed"]
    );
    assert!(
        !comparison
            .files
            .iter()
            .any(|f| f.path == Path::new("ignored-untracked"))
    );
    let moved = changed(&comparison, Path::new("rename-new"));
    assert_eq!(moved.status, FileStatus::Renamed);
    assert_eq!(moved.old_path.as_deref(), Some(Path::new("rename-old")));
    assert_eq!(moved.before, moved.after);
    assert!(moved.hunks.is_empty());
    let reverse = compare_loaded(
        &mut repository,
        &working(RepoKind::Git),
        &revision(&id, RepoKind::Git),
        &[],
    )
    .unwrap();
    assert!(reverse.editable_paths.is_empty());
    assert_eq!(
        changed(&reverse, Path::new("added")).status,
        FileStatus::Removed
    );
    assert!(
        repository
            .compare(
                1,
                &working(RepoKind::Git),
                &working(RepoKind::Git),
                ComparisonMode::Snapshots,
                &[]
            )
            .unwrap()
            .files
            .is_empty()
    );
    assert_eq!(disk_state(&root), state);
}

#[test]
fn git_remote_refs_and_annotated_tags_are_discovered_before_fetch_and_history_stays_private() {
    let fixture = Fixture::new();
    let source = fixture.dir("source");
    init_git(&source);
    fs::write(source.join("file"), "ancestor\n").unwrap();
    git(&source, &["add", "."]);
    git(&source, &["commit", "-m", "remote ancestor needle"]);
    let ancestor = git(&source, &["rev-parse", "HEAD"]);
    git(&source, &["tag", "-a", "ancestor-tag", "-m", "annotated"]);
    fs::write(source.join("file"), "remote tip\n").unwrap();
    git(&source, &["commit", "-am", "remote tip"]);
    let tip = git(&source, &["rev-parse", "HEAD"]);
    git(&source, &["branch", "never-fetched"]);
    let bare = fixture.0.join("remote.git");
    git(
        &fixture.0,
        &[
            "clone",
            "--bare",
            source.to_str().unwrap(),
            bare.to_str().unwrap(),
        ],
    );
    let active = fixture.dir("active");
    init_git(&active);
    fs::write(active.join("file"), "local\n").unwrap();
    git(&active, &["add", "."]);
    git(&active, &["commit", "-m", "local"]);
    let local = git(&active, &["rev-parse", "HEAD"]);
    git(
        &active,
        &["remote", "add", "origin", bare.to_str().unwrap()],
    );
    let state = disk_state(&active);
    let mut repository = open(&active);
    let catalog = repository.list_remote("origin").unwrap();
    let remote = catalog
        .entries
        .iter()
        .find(|r| {
            r.target
                == (RevisionTarget::Remote {
                    remote: "origin".into(),
                    reference: "refs/heads/never-fetched".into(),
                })
        })
        .unwrap()
        .clone();
    let tag = catalog
        .entries
        .iter()
        .find(|r| {
            r.target
                == (RevisionTarget::Remote {
                    remote: "origin".into(),
                    reference: "refs/tags/ancestor-tag".into(),
                })
        })
        .unwrap()
        .clone();
    assert!(
        catalog
            .entries
            .iter()
            .any(|r| r.target == RevisionTarget::FetchRemote("origin".into()))
    );
    assert!(
        !catalog
            .entries
            .iter()
            .any(|r| r.target == RevisionTarget::Commit(ancestor.clone()))
    );
    assert!(
        !command("git", &active, &["cat-file", "-e", &tip])
            .status
            .success()
    );
    let comparison = compare_loaded(
        &mut repository,
        &revision(&local, RepoKind::Git),
        &remote,
        &[(active.join("file"), "unsaved local text\n".into())],
    )
    .unwrap();
    assert!(comparison.editable_paths.is_empty());
    assert_eq!(changed(&comparison, Path::new("file")).before, ["local"]);
    assert_eq!(
        changed(&comparison, Path::new("file")).after,
        ["remote tip"]
    );
    let comparison = compare_loaded(&mut repository, &tag, &remote, &[]).unwrap();
    assert_eq!(changed(&comparison, Path::new("file")).before, ["ancestor"]);
    let comparison =
        compare_loaded(&mut repository, &remote, &working(RepoKind::Git), &[]).unwrap();
    assert_eq!(changed(&comparison, Path::new("file")).after, ["local"]);
    let loaded = repository.fetch_remote("origin").unwrap();
    let historic = loaded
        .entries
        .iter()
        .find(|r| {
            r.target == RevisionTarget::Commit(ancestor.clone()) && r.category == Category::Commits
        })
        .unwrap();
    assert_eq!(historic.label, ancestor);
    assert_eq!(historic.description, "remote ancestor needle");
    let comparison = compare_loaded(
        &mut repository,
        historic,
        &revision(&local, RepoKind::Git),
        &[],
    )
    .unwrap();
    assert_eq!(changed(&comparison, Path::new("file")).before, ["ancestor"]);
    assert!(
        !command("git", &active, &["cat-file", "-e", &tip])
            .status
            .success()
    );
    assert_eq!(disk_state(&active), state);
}

#[test]
fn jj_catalog_and_working_comparisons_prefer_jj_and_never_snapshot_or_merge_operations() {
    for colocate in [false, true] {
        let fixture = Fixture::new();
        let active = fixture.dir("active");
        init_jj(&active, colocate);
        fs::write(active.join("file"), "baseline\n").unwrap();
        fs::write(active.join("deleted"), "delete\n").unwrap();
        fs::write(active.join(".gitignore"), "ignored-*\n").unwrap();
        jj(&active, &["describe", "-m", "jj baseline searchable"]);
        let id = jj(
            &active,
            &[
                "--ignore-working-copy",
                "--at-operation=@",
                "log",
                "--no-graph",
                "-r",
                "@",
                "-T",
                "commit_id",
            ],
        );
        jj(&active, &["bookmark", "create", "baseline"]);
        jj(&active, &["new"]);
        fs::write(active.join("file"), "disk\n").unwrap();
        fs::remove_file(active.join("deleted")).unwrap();
        fs::write(active.join("addition"), "new\n").unwrap();
        fs::write(active.join("ignored-untracked"), "ignored\n").unwrap();
        let state = disk_state(&active);
        let mut repository = open(&active);
        let catalog = repository.catalog().unwrap();
        assert_eq!(catalog.kind, RepoKind::Jujutsu);
        let baseline = catalog
            .entries
            .iter()
            .find(|r| {
                r.target == RevisionTarget::Commit(id.clone()) && r.category == Category::Revisions
            })
            .unwrap();
        assert!(
            catalog
                .entries
                .iter()
                .any(|r| r.label == "baseline" && r.category == Category::Bookmarks)
        );
        let comparison =
            compare_loaded(&mut repository, baseline, &working(RepoKind::Jujutsu), &[]).unwrap();
        assert_eq!(changed(&comparison, Path::new("file")).after, ["disk"]);
        assert_eq!(
            changed(&comparison, Path::new("deleted")).status,
            FileStatus::Removed
        );
        assert_eq!(
            changed(&comparison, Path::new("addition")).status,
            FileStatus::Added
        );
        assert!(
            !comparison
                .files
                .iter()
                .any(|f| f.path == Path::new("ignored-untracked"))
        );
        let synthetic_root = revision(&"0".repeat(40), RepoKind::Jujutsu);
        let branch = repository
            .compare(
                20,
                &synthetic_root,
                baseline,
                ComparisonMode::BranchChanges,
                &[],
            )
            .unwrap();
        assert!(branch.before.ends_with(&"0".repeat(40)));
        assert!(
            branch
                .files
                .iter()
                .any(|file| file.path == Path::new("file"))
        );
        let reversed = repository
            .compare(
                21,
                baseline,
                &synthetic_root,
                ComparisonMode::BranchChanges,
                &[],
            )
            .unwrap();
        assert!(reversed.files.is_empty());
        assert!(
            repository
                .compare(22, baseline, baseline, ComparisonMode::BranchChanges, &[])
                .unwrap()
                .files
                .is_empty()
        );
        assert_eq!(disk_state(&active), state);
    }
}

#[test]
fn jj_private_fetch_discovers_never_fetched_bookmark_and_searchable_remote_change_history() {
    let fixture = Fixture::new();
    let source = fixture.dir("source");
    init_jj(&source, false);
    fs::write(source.join("file"), "remote ancestor\n").unwrap();
    jj(&source, &["describe", "-m", "remote historic needle"]);
    let ancestor = jj(
        &source,
        &[
            "--ignore-working-copy",
            "log",
            "--no-graph",
            "-r",
            "@",
            "-T",
            "commit_id",
        ],
    );
    jj(&source, &["new"]);
    fs::write(source.join("file"), "remote tip\n").unwrap();
    jj(&source, &["describe", "-m", "remote tip"]);
    let tip = jj(
        &source,
        &[
            "--ignore-working-copy",
            "log",
            "--no-graph",
            "-r",
            "@",
            "-T",
            "commit_id",
        ],
    );
    jj(&source, &["bookmark", "create", "never-fetched"]);
    let bare = fixture.dir("remote.git");
    jj(&source, &["git", "export"]);
    // Build remote fixture data by copying exported refs, never by pushing.
    git(
        &fixture.0,
        &[
            "clone",
            "--bare",
            "--no-hardlinks",
            source.join(".jj/repo/store/git").to_str().unwrap(),
            bare.to_str().unwrap(),
        ],
    );
    let active = fixture.dir("active");
    init_jj(&active, false);
    fs::write(active.join("file"), "local\n").unwrap();
    jj(&active, &["describe", "-m", "local"]);
    jj(&active, &["new"]);
    jj(
        &active,
        &["git", "remote", "add", "origin", bare.to_str().unwrap()],
    );
    fs::write(active.join("unsnapshotted"), "keep disk\n").unwrap();
    let state = disk_state(&active);
    let mut repository = open(&active);
    let catalog = repository.list_remote("origin").unwrap();
    let remote = catalog
        .entries
        .iter()
        .find(|r| {
            r.target
                == (RevisionTarget::Remote {
                    remote: "origin".into(),
                    reference: "refs/heads/never-fetched".into(),
                })
        })
        .unwrap()
        .clone();
    assert!(
        !catalog
            .entries
            .iter()
            .any(|r| r.target == RevisionTarget::Commit(ancestor.clone()))
    );
    let local = catalog.entries.iter().find(|revision| {
        matches!(&revision.target, RevisionTarget::Commit(id) if id.bytes().any(|byte| byte != b'0'))
    }).unwrap();
    let branch = repository
        .compare(60, local, &remote, ComparisonMode::BranchChanges, &[])
        .unwrap();
    assert!(branch.before.ends_with(&"0".repeat(40)));
    assert_eq!(branch.files.len(), 1);
    assert_eq!(repository.load_file(60, 0).unwrap().after, ["remote tip"]);
    let comparison =
        compare_loaded(&mut repository, &remote, &working(RepoKind::Jujutsu), &[]).unwrap();
    assert_eq!(
        changed(&comparison, Path::new("file")).before,
        ["remote tip"]
    );
    assert_eq!(changed(&comparison, Path::new("file")).after, ["local"]);
    let loaded = repository.fetch_remote("origin").unwrap();
    let historic = loaded
        .entries
        .iter()
        .find(|r| {
            r.target == RevisionTarget::Commit(ancestor.clone())
                && r.category == Category::Revisions
        })
        .unwrap();
    let comparison = compare_loaded(&mut repository, historic, &remote, &[]).unwrap();
    assert_eq!(
        changed(&comparison, Path::new("file")).before,
        ["remote ancestor"]
    );
    assert_eq!(
        changed(&comparison, Path::new("file")).after,
        ["remote tip"]
    );
    let branch = repository
        .compare(61, historic, &remote, ComparisonMode::BranchChanges, &[])
        .unwrap();
    assert!(branch.before.ends_with(&ancestor));
    assert_eq!(
        repository.load_file(61, 0).unwrap().before,
        ["remote ancestor"]
    );
    let store = active.join(".jj/repo/store");
    let active_store =
        fs::canonicalize(store.join(fs::read_to_string(store.join("git_target")).unwrap().trim()))
            .unwrap();
    assert!(
        !command(
            "git",
            &active,
            &[
                "--git-dir",
                active_store.to_str().unwrap(),
                "cat-file",
                "-e",
                &tip
            ]
        )
        .status
        .success()
    );
    assert_eq!(disk_state(&active), state);
}

#[test]
fn errors_are_explicit_and_do_not_modify_active_repository() {
    let fixture = Fixture::new();
    assert!(Repository::open(&fixture.0, Arc::new(AtomicBool::new(false))).is_err());
    let root = fixture.dir("active");
    init_git(&root);
    fs::write(root.join("file"), "baseline\n").unwrap();
    git(&root, &["add", "."]);
    git(&root, &["commit", "-m", "baseline"]);
    let id = git(&root, &["rev-parse", "HEAD"]);
    git(
        &root,
        &[
            "remote",
            "add",
            "broken",
            fixture.0.join("missing.git").to_str().unwrap(),
        ],
    );
    let state = disk_state(&root);
    let mut repository = open(&root);
    let catalog = repository.catalog().unwrap();
    assert!(catalog.notice.is_none());
    assert!(
        catalog
            .entries
            .iter()
            .any(|revision| revision.target == RevisionTarget::ListRemote("broken".into()))
    );
    assert!(repository.list_remote("broken").is_err());
    assert!(repository.fetch_remote("broken").is_err());
    assert!(
        repository
            .fetch_remote("unknown")
            .unwrap_err()
            .contains("Unknown configured remote")
    );
    assert!(
        repository
            .compare(
                1,
                &revision("--bad", RepoKind::Git),
                &working(RepoKind::Git),
                ComparisonMode::Snapshots,
                &[]
            )
            .unwrap_err()
            .contains("Invalid immutable commit")
    );
    assert!(
        repository
            .compare(
                1,
                &revision(&"f".repeat(40), RepoKind::Git),
                &working(RepoKind::Git),
                ComparisonMode::Snapshots,
                &[],
            )
            .unwrap_err()
            .contains("unavailable")
    );
    let loader = Revision {
        target: RevisionTarget::FetchRemote("broken".into()),
        ..working(RepoKind::Git)
    };
    assert!(
        repository
            .compare(
                1,
                &loader,
                &revision(&id, RepoKind::Git),
                ComparisonMode::Snapshots,
                &[]
            )
            .unwrap_err()
            .contains("history loader")
    );
    assert!(
        Repository::open(&root, Arc::new(AtomicBool::new(true)))
            .err()
            .unwrap()
            .contains("cancelled")
    );
    assert_eq!(disk_state(&root), state);
}

#[test]
fn unchanged_submodules_are_not_false_changes_and_changed_pointers_are_explicit() {
    let fixture = Fixture::new();
    let child = fixture.dir("child");
    init_git(&child);
    fs::write(child.join("file"), "first\n").unwrap();
    git(&child, &["add", "."]);
    git(&child, &["commit", "-m", "first"]);
    let first = git(&child, &["rev-parse", "HEAD"]);
    let root = fixture.dir("active");
    init_git(&root);
    git(
        &root,
        &[
            "-c",
            "protocol.file.allow=always",
            "submodule",
            "add",
            child.to_str().unwrap(),
            "nested",
        ],
    );
    git(&root, &["commit", "-m", "submodule"]);
    let baseline = git(&root, &["rev-parse", "HEAD"]);
    let mut repository = open(&root);
    assert!(
        repository
            .compare(
                1,
                &revision(&baseline, RepoKind::Git),
                &working(RepoKind::Git),
                ComparisonMode::Snapshots,
                &[]
            )
            .unwrap()
            .files
            .is_empty()
    );
    fs::write(child.join("file"), "second\n").unwrap();
    git(&child, &["commit", "-am", "second"]);
    let second = git(&child, &["rev-parse", "HEAD"]);
    git(&root.join("nested"), &["fetch", "origin"]);
    git(&root.join("nested"), &["checkout", "--detach", &second]);
    let state = disk_state(&root);
    let comparison = compare_loaded(
        &mut repository,
        &revision(&baseline, RepoKind::Git),
        &working(RepoKind::Git),
        &[],
    )
    .unwrap();
    let submodule = changed(&comparison, Path::new("nested"));
    assert_eq!(submodule.status, FileStatus::Modified);
    let notice = submodule.notice.as_ref().unwrap();
    assert!(
        notice.contains(&first) && notice.contains(&second) && notice.contains("not traversed")
    );
    assert!(submodule.before.is_empty() && submodule.after.is_empty());
    assert!(
        !comparison
            .files
            .iter()
            .any(|f| f.path.starts_with("nested/file"))
    );
    assert_eq!(disk_state(&root), state);
}

#[test]
fn multiple_remotes_retain_tag_only_history_even_when_tag_names_collide() {
    let fixture = Fixture::new();
    let mut ids = vec![];
    let mut urls = vec![];
    for name in ["one", "two"] {
        let source = fixture.dir(name);
        init_git(&source);
        fs::write(source.join("file"), format!("{name}\n")).unwrap();
        git(&source, &["add", "."]);
        git(
            &source,
            &["commit", "-m", &format!("{name} tag-only needle")],
        );
        ids.push(git(&source, &["rev-parse", "HEAD"]));
        git(&source, &["tag", "collision"]);
        git(&source, &["update-ref", "-d", "refs/heads/local"]);
        let bare = fixture.0.join(format!("{name}.git"));
        git(
            &fixture.0,
            &[
                "clone",
                "--bare",
                source.to_str().unwrap(),
                bare.to_str().unwrap(),
            ],
        );
        urls.push(bare);
    }
    let active = fixture.dir("active");
    init_git(&active);
    fs::write(active.join("local"), "local\n").unwrap();
    git(&active, &["add", "."]);
    git(&active, &["commit", "-m", "local"]);
    for (name, url) in ["one", "two"].into_iter().zip(&urls) {
        git(&active, &["remote", "add", name, url.to_str().unwrap()]);
    }
    let state = disk_state(&active);
    let mut repository = open(&active);
    repository.fetch_remote("one").unwrap();
    let loaded = repository.fetch_remote("two").unwrap();
    for (name, id) in ["one", "two"].into_iter().zip(&ids) {
        assert!(
            loaded
                .entries
                .iter()
                .any(|r| r.target == RevisionTarget::Commit(id.clone())
                    && r.description == format!("{name} tag-only needle"))
        );
    }
    let comparison = compare_loaded(
        &mut repository,
        &revision(&ids[0], RepoKind::Git),
        &revision(&ids[1], RepoKind::Git),
        &[],
    )
    .unwrap();
    assert_eq!(changed(&comparison, Path::new("file")).before, ["one"]);
    assert_eq!(changed(&comparison, Path::new("file")).after, ["two"]);
    assert_eq!(disk_state(&active), state);
}

#[test]
fn jj_conflicted_revisions_show_cli_projection_and_keep_ordinary_files_navigable() {
    let fixture = Fixture::new();
    let root = fixture.dir("active");
    init_jj(&root, false);
    fs::write(root.join("conflict"), "base\n").unwrap();
    fs::write(root.join("ordinary"), "old\n").unwrap();
    jj(&root, &["describe", "-m", "base"]);
    let base = jj(
        &root,
        &[
            "--ignore-working-copy",
            "log",
            "--no-graph",
            "-r",
            "@",
            "-T",
            "commit_id",
        ],
    );
    jj(&root, &["new", &base]);
    fs::write(root.join("conflict"), "left\n").unwrap();
    fs::write(root.join("ordinary"), "left ordinary\n").unwrap();
    jj(&root, &["describe", "-m", "left"]);
    let left = jj(
        &root,
        &[
            "--ignore-working-copy",
            "log",
            "--no-graph",
            "-r",
            "@",
            "-T",
            "commit_id",
        ],
    );
    jj(&root, &["new", &base]);
    fs::write(root.join("conflict"), "right\n").unwrap();
    jj(&root, &["describe", "-m", "right"]);
    let right = jj(
        &root,
        &[
            "--ignore-working-copy",
            "log",
            "--no-graph",
            "-r",
            "@",
            "-T",
            "commit_id",
        ],
    );
    jj(&root, &["new", &left, &right, "-m", "conflicted merge"]);
    let merged = jj(
        &root,
        &[
            "--ignore-working-copy",
            "--at-operation=@",
            "log",
            "--no-graph",
            "-r",
            "@",
            "-T",
            "commit_id",
        ],
    );
    let projection = command(
        "jj",
        &root,
        &[
            "--ignore-working-copy",
            "--at-operation=@",
            "file",
            "show",
            "-r",
            &merged,
            "-T",
            "",
            "--",
            "root-file:\"conflict\"",
        ],
    );
    assert!(
        projection.status.success(),
        "{}",
        String::from_utf8_lossy(&projection.stderr)
    );
    let projection = String::from_utf8(projection.stdout).unwrap();
    let expected: Vec<_> = projection
        .strip_suffix('\n')
        .unwrap_or(&projection)
        .split('\n')
        .map(str::to_owned)
        .collect();
    let state = disk_state(&root);
    let mut repository = open(&root);
    let catalog = repository.catalog().unwrap();
    assert!(
        catalog
            .entries
            .iter()
            .any(|r| r.target == RevisionTarget::Commit(merged.clone()))
    );
    let comparison = compare_loaded(
        &mut repository,
        &revision(&base, RepoKind::Jujutsu),
        &revision(&merged, RepoKind::Jujutsu),
        &[],
    )
    .unwrap();
    let conflict = changed(&comparison, Path::new("conflict"));
    assert_eq!(conflict.after, expected);
    assert!(
        conflict
            .notice
            .as_ref()
            .unwrap()
            .contains("conflict projection")
    );
    assert!(!conflict.hunks.is_empty());
    let ordinary = changed(&comparison, Path::new("ordinary"));
    assert_eq!(ordinary.before, ["old"]);
    assert_eq!(ordinary.after, ["left ordinary"]);
    assert!(ordinary.notice.is_none());
    let branch = repository
        .compare(
            30,
            &revision(&base, RepoKind::Jujutsu),
            &revision(&merged, RepoKind::Jujutsu),
            ComparisonMode::BranchChanges,
            &[],
        )
        .unwrap();
    let index = branch
        .files
        .iter()
        .position(|file| file.path == Path::new("conflict"))
        .unwrap();
    let conflict = repository.load_file(30, index).unwrap();
    assert_eq!(conflict.after, expected);
    assert!(
        conflict
            .notice
            .as_deref()
            .unwrap()
            .contains("conflict projection")
    );
    let working_comparison = compare_loaded(
        &mut repository,
        &revision(&merged, RepoKind::Jujutsu),
        &working(RepoKind::Jujutsu),
        &[],
    )
    .unwrap();
    assert!(
        changed(&working_comparison, Path::new("conflict"))
            .notice
            .as_ref()
            .unwrap()
            .contains("conflict projection")
    );
    assert_eq!(disk_state(&root), state);
}

#[test]
fn unsaved_overlays_are_working_after_only_and_cannot_follow_nonregular_paths() {
    let fixture = Fixture::new();
    let root = fs::canonicalize(fixture.dir("overlay")).unwrap();
    init_git(&root);
    fs::create_dir(root.join("sub")).unwrap();
    fs::write(root.join("file"), "base\n").unwrap();
    fs::write(root.join("sub/file"), "nested\n").unwrap();
    fs::write(root.join("binary"), b"\0binary").unwrap();
    git(&root, &["add", "."]);
    git(&root, &["commit", "-m", "base"]);
    let id = git(&root, &["rev-parse", "HEAD"]);
    let outside = fixture.dir("outside");
    fs::write(outside.join("file"), "outside\n").unwrap();
    symlink(&outside, root.join("linked")).unwrap();
    symlink("file", root.join("link")).unwrap();
    let state = disk_state(&root);
    let buffers = vec![
        (root.join("file"), "unsaved\n".into()),
        (root.join("binary"), "not binary\n".into()),
        (root.join("missing"), "not on disk\n".into()),
        (root.join("link"), "not a regular file\n".into()),
        (root.join("linked/file"), "outside via link\n".into()),
        (outside.join("file"), "outside\n".into()),
        (root.join("sub/../../outside/file"), "escaped\n".into()),
        (root.join(".git/config"), "metadata\n".into()),
    ];
    let mut repository = open(&root.join("sub"));
    let base = revision(&id, RepoKind::Git);
    let checkout = working(RepoKind::Git);
    let comparison = compare_loaded(&mut repository, &base, &checkout, &buffers).unwrap();
    assert_eq!(comparison.root, fs::canonicalize(&root).unwrap());
    assert_eq!(changed(&comparison, Path::new("file")).after, ["unsaved"]);
    assert!(comparison.editable_paths.contains(Path::new("file")));
    for path in [
        "binary",
        "missing",
        "link",
        "linked",
        "linked/file",
        ".git/config",
    ] {
        assert!(!comparison.editable_paths.contains(Path::new(path)));
    }
    assert!(
        !comparison
            .files
            .iter()
            .any(|file| file.path == Path::new("binary")
                || file.path == Path::new("missing")
                || file.path == Path::new("linked/file"))
    );
    let immutable = compare_loaded(&mut repository, &checkout, &base, &buffers).unwrap();
    assert!(immutable.editable_paths.is_empty());
    assert!(
        !immutable
            .files
            .iter()
            .any(|file| file.path == Path::new("file"))
    );
    assert!(
        repository
            .compare(1, &base, &base, ComparisonMode::Snapshots, &buffers)
            .unwrap()
            .files
            .is_empty()
    );
    let same_checkout = compare_loaded(&mut repository, &checkout, &checkout, &buffers).unwrap();
    assert_eq!(changed(&same_checkout, Path::new("file")).before, ["base"]);
    assert_eq!(
        changed(&same_checkout, Path::new("file")).after,
        ["unsaved"]
    );
    assert_eq!(disk_state(&root), state);
    assert_eq!(
        fs::read_to_string(outside.join("file")).unwrap(),
        "outside\n"
    );
}

#[test]
fn immutable_catalog_skips_unchanged_blobs_and_prepares_only_requested_details() {
    let fixture = Fixture::new();
    let root = fixture.dir("lazy");
    init_git(&root);
    fs::write(root.join("unchanged-large"), vec![b'x'; 17 * 1024 * 1024]).unwrap();
    fs::write(root.join("selected"), "before\n").unwrap();
    fs::write(root.join("unselected"), "old\n").unwrap();
    git(&root, &["add", "."]);
    git(&root, &["commit", "-m", "before"]);
    let before = git(&root, &["rev-parse", "HEAD"]);
    fs::write(root.join("selected"), "after\n").unwrap();
    fs::write(root.join("unselected"), vec![b'y'; 17 * 1024 * 1024]).unwrap();
    git(&root, &["add", "."]);
    git(&root, &["commit", "-m", "after"]);
    let after = git(&root, &["rev-parse", "HEAD"]);
    let mut repository = open(&root);
    let comparison = repository
        .compare(
            100,
            &revision(&before, RepoKind::Git),
            &revision(&after, RepoKind::Git),
            ComparisonMode::Snapshots,
            &[],
        )
        .unwrap();
    assert_eq!(comparison.files.len(), 2);
    assert!(comparison.files.iter().all(|file| !file.loaded
        && file.before.is_empty()
        && file.after.is_empty()
        && file.hunks.is_empty()));
    let index = comparison
        .files
        .iter()
        .position(|file| file.path == Path::new("selected"))
        .unwrap();
    let selected = repository.load_file(100, index).unwrap();
    assert!(selected.loaded);
    assert_eq!(selected.before, ["before"]);
    assert_eq!(selected.after, ["after"]);
    assert_eq!(selected.hunks.len(), 1);
    assert!(repository.load_file(99, index).is_err());
    let empty = repository
        .compare(
            101,
            &revision(&after, RepoKind::Git),
            &revision(&after, RepoKind::Git),
            ComparisonMode::Snapshots,
            &[],
        )
        .unwrap();
    assert!(empty.files.is_empty());
    assert!(repository.load_file(100, index).is_err());
}

#[test]
fn deferred_file_details_keep_frozen_checkout_and_unsaved_after() {
    let fixture = Fixture::new();
    let root = fixture.dir("frozen").canonicalize().unwrap();
    init_git(&root);
    fs::write(root.join("file"), "committed\n").unwrap();
    git(&root, &["add", "."]);
    git(&root, &["commit", "-m", "before"]);
    fs::write(root.join("file"), "disk before\n").unwrap();
    let mut repository = open(&root);
    let comparison = repository
        .compare(
            50,
            &working(RepoKind::Git),
            &working(RepoKind::Git),
            ComparisonMode::Snapshots,
            &[(root.join("file"), "unsaved after\n".into())],
        )
        .unwrap();
    assert_eq!(comparison.files.len(), 1);
    assert!(!comparison.files[0].loaded);
    fs::write(root.join("file"), "later disk\n").unwrap();
    let details = repository.load_file(50, 0).unwrap();
    assert_eq!(details.before, ["disk before"]);
    assert_eq!(details.after, ["unsaved after"]);
    let again = repository.load_file(50, 0).unwrap();
    assert_eq!(again.before, details.before);
    assert_eq!(again.after, details.after);
}

#[test]
fn branch_changes_resolves_local_and_private_remote_ancestry_without_active_mutation() {
    let fixture = Fixture::new();
    let active = fixture.dir("active\nquoted\"\\");
    init_git(&active);
    fs::write(active.join("common"), "base\n").unwrap();
    git(&active, &["add", "."]);
    git(&active, &["commit", "-m", "base"]);
    let base = git(&active, &["rev-parse", "HEAD"]);
    let source = fixture.0.join("source");
    git(
        &fixture.0,
        &["clone", active.to_str().unwrap(), source.to_str().unwrap()],
    );
    git(&source, &["config", "user.name", "Diff Test"]);
    git(&source, &["config", "user.email", "diff@example.invalid"]);
    fs::write(source.join("remote-only"), "remote\n").unwrap();
    git(&source, &["add", "."]);
    git(&source, &["commit", "-m", "remote"]);
    fs::write(active.join("local-only"), "local\n").unwrap();
    git(&active, &["add", "."]);
    git(&active, &["commit", "-m", "local"]);
    let local = revision(&git(&active, &["rev-parse", "HEAD"]), RepoKind::Git);
    git(
        &active,
        &["remote", "add", "origin", source.to_str().unwrap()],
    );
    let state = disk_state(&active);
    let mut repository = open(&active);
    let catalog = repository.list_remote("origin").unwrap();
    let remote = catalog
        .entries
        .iter()
        .find(|r| matches!(r.target, RevisionTarget::Remote { .. }))
        .unwrap();
    let branch = repository
        .compare(40, &local, remote, ComparisonMode::BranchChanges, &[])
        .unwrap();
    assert_eq!(branch.files.len(), 1);
    assert_eq!(branch.files[0].path, Path::new("remote-only"));
    assert!(branch.before.ends_with(&base));
    assert_eq!(repository.load_file(40, 0).unwrap().after, ["remote"]);
    let reverse = repository
        .compare(41, remote, &local, ComparisonMode::BranchChanges, &[])
        .unwrap();
    assert_eq!(reverse.files.len(), 1);
    assert_eq!(reverse.files[0].path, Path::new("local-only"));
    assert_eq!(repository.load_file(41, 0).unwrap().after, ["local"]);
    assert!(
        repository
            .compare(42, &local, &local, ComparisonMode::BranchChanges, &[])
            .unwrap()
            .files
            .is_empty()
    );
    assert_eq!(disk_state(&active), state);
}

#[test]
fn branch_changes_rejects_missing_and_multiple_merge_bases_without_snapshot_fallback() {
    let fixture = Fixture::new();
    let root = fixture.dir("graphs");
    init_git(&root);
    fs::write(root.join("file"), "base\n").unwrap();
    git(&root, &["add", "."]);
    git(&root, &["commit", "-m", "base"]);
    let base = git(&root, &["rev-parse", "HEAD"]);
    let tree = git(&root, &["rev-parse", "HEAD^{tree}"]);
    let left = git(&root, &["commit-tree", &tree, "-p", &base, "-m", "left"]);
    let right = git(&root, &["commit-tree", &tree, "-p", &base, "-m", "right"]);
    let one = git(
        &root,
        &["commit-tree", &tree, "-p", &left, "-p", &right, "-m", "one"],
    );
    let two = git(
        &root,
        &["commit-tree", &tree, "-p", &right, "-p", &left, "-m", "two"],
    );
    let unrelated = git(&root, &["commit-tree", &tree, "-m", "unrelated"]);
    let state = disk_state(&root);
    let mut repository = open(&root);
    for (before, after, message) in [
        (&base, &unrelated, "no merge base"),
        (&one, &two, "multiple merge bases"),
    ] {
        let before = revision(before, RepoKind::Git);
        let after = revision(after, RepoKind::Git);
        assert!(
            repository
                .compare(50, &before, &after, ComparisonMode::BranchChanges, &[])
                .unwrap_err()
                .contains(message)
        );
        assert!(
            repository
                .compare(51, &before, &after, ComparisonMode::Snapshots, &[])
                .unwrap()
                .files
                .is_empty()
        );
    }
    assert_eq!(disk_state(&root), state);
}