vamp/tests/unit/diff.rs

use super::*;
use crate::editor::{Editor, Effect, Mode};
std::thread_local! {
    pub(super) static WIDTH_SCANS: std::cell::Cell<usize> = const { std::cell::Cell::new(0) };
}

#[test]
fn conflict_history_preserves_source_gaps_base_changes_and_native_eof_rows() {
    let history = HistoryComparison::new([
        "xbc def\nkeep\n",
        "abc def\nkeep\n",
        "abc deg\nadded\nkeep\n",
    ]);
    let rows: Vec<_> = (0..history.row_count())
        .map(|row| {
            std::array::from_fn::<_, 3, _>(|column| history.column(column).view().native_row(row))
        })
        .collect();
    assert_eq!(
        rows,
        [
            [Some(0), Some(0), Some(0)],
            [None, None, Some(1)],
            [Some(1), Some(1), Some(2)],
            [Some(2), Some(2), Some(3)],
        ]
    );
    for column in 0..3 {
        let history_column = history.column(column);
        let projection = history_column.view();
        for (display, row) in rows.iter().enumerate() {
            if let Some(source) = row[column] {
                assert_eq!(projection.display_row(source), Some(display));
            }
        }
    }
    let base = history.column(1);
    let base = base.view();
    let ColumnRow::Text(line) = base.row(0).unwrap() else {
        panic!("changed base row must contain text");
    };
    assert!(line.changed);
    for column in [0, 6] {
        assert!(line.changes().any(|range| range.contains(&column)));
    }
    assert!(!line.changes().any(|range| range.contains(&4)));
    let ColumnRow::Text(line) = base.row(2).unwrap() else {
        panic!("unchanged base row must contain text");
    };
    assert!(!line.changed);
    assert_eq!(line.changes().count(), 0);
    let right = history.column(2);
    let ColumnRow::Text(line) = right.view().row(1).unwrap() else {
        panic!("inserted right row must contain text");
    };
    assert_eq!(line.text, Some("added"));
    assert!(matches!(base.row(1), Some(ColumnRow::Gap)));

    // Rebuilding for a new input/base choice must not retain old source mappings.
    let history = HistoryComparison::new([
        "abc def\nkeep\n",
        "abc deg\nadded\nkeep\n",
        "xbc def\nkeep\n",
    ]);
    assert_eq!(history.column(1).view().native_row(1), Some(1));
    assert_eq!(history.column(0).view().native_row(1), None);
    assert_eq!(history.column(2).view().native_row(1), None);
    for text in ["", "\n", "same", "same\n"] {
        let history = HistoryComparison::new([text; 3]);
        let native_rows = text.split('\n').count();
        assert_eq!(history.row_count(), native_rows);
        for column in 0..3 {
            for row in 0..native_rows {
                assert_eq!(history.column(column).view().native_row(row), Some(row));
                assert_eq!(history.column(column).view().display_row(row), Some(row));
            }
        }
    }
}

#[test]
fn resolver_equal_text_retains_native_rows_and_cached_viewport() {
    for text in ["", "\n", "same\n", "same"] {
        let lines: Vec<_> = text.split('\n').map(str::to_owned).collect();
        let mut state = DiffState::new();
        state.set_resolver_text(&lines, &lines);
        assert_eq!(state.pane_layout(), PaneLayout::Split);
        assert!(state.comparison.as_ref().unwrap().files[0].hunks.is_empty());
        assert_eq!(
            state.comparison.as_ref().unwrap().files[0].path,
            Path::new("resolution.txt")
        );
        assert_eq!(state.files.as_ref().unwrap().entries().len(), 1);
        for row in 0..lines.len() {
            assert!(state.source_display_row(Focus::Before, row).is_some());
            assert!(state.source_display_row(Focus::After, row).is_some());
        }
        let id = state.comparison_id;
        state.top = 1;
        state.left_before = 3;
        state.left_after = 4;
        state.set_resolver_text(&lines, &lines);
        assert_eq!(state.comparison_id, id);
        assert_eq!((state.top, state.left_before, state.left_after), (1, 3, 4));
    }
}

#[test]
fn resolver_catalog_reveals_the_current_native_file() {
    let mut state = DiffState::new();
    state.set_resolver_paths(
        PathBuf::new(),
        vec!["binary.bin".into(), "first.txt".into(), "second.txt".into()],
        1,
    );
    let files = state.files.as_ref().unwrap();
    assert_eq!(
        files.entries().nth(files.selected).unwrap().path,
        Path::new("first.txt")
    );
    assert!(!files.is_conflicted(Path::new("first.txt")));
    state
        .files
        .as_mut()
        .unwrap()
        .set_conflicted(Path::new("first.txt"), true);
    state.set_resolver_paths(
        PathBuf::new(),
        vec!["binary.bin".into(), "first.txt".into(), "second.txt".into()],
        2,
    );
    let files = state.files.as_ref().unwrap();
    assert_eq!(
        files.entries().nth(files.selected).unwrap().path,
        Path::new("second.txt")
    );
    assert!(files.is_conflicted(Path::new("first.txt")));
    assert!(!files.is_conflicted(Path::new("second.txt")));
}

fn excerpt_state(len: usize, changed: &[usize]) -> DiffState {
    let mut state = DiffState::new();
    state.phase = Phase::View;
    state.focus = Focus::Before;
    state.rows = (0..len)
        .map(|index| AlignedRow {
            before: Some(index),
            after: Some(index + 3),
            kind: if changed.contains(&index) {
                RowKind::Changed
            } else {
                RowKind::Equal
            },
            changes: Vec::new(),
        })
        .collect();
    state.reset_excerpts();
    state
}

#[test]
fn excerpts_cover_context_and_hidden_rows_once_without_reindexing() {
    let state = excerpt_state(100, &[30, 70]);
    assert_eq!(state.excerpt_ranges, [(20, 41), (60, 81)]);
    assert_eq!(
        state.display_rows[0],
        DisplayRow::Fold { start: 0, end: 20 }
    );
    assert_eq!(
        state.display_rows[22],
        DisplayRow::Fold { start: 41, end: 60 }
    );
    assert_eq!(
        state.display_rows[44],
        DisplayRow::Fold {
            start: 81,
            end: 100
        }
    );
    let mut covered = Vec::new();
    for row in &state.display_rows {
        match *row {
            DisplayRow::Line(index) => {
                covered.push(index);
                assert_eq!(state.rows[index].before, Some(index));
                assert_eq!(state.rows[index].after, Some(index + 3));
            }
            DisplayRow::Fold { start, end } => {
                assert!(
                    state.rows[start..end]
                        .iter()
                        .all(|row| row.kind == RowKind::Equal)
                );
                covered.extend(start..end);
            }
        }
    }
    assert_eq!(covered, (0..100).collect::<Vec<_>>());
    for index in [30, 70] {
        assert_eq!(
            state
                .display_rows
                .iter()
                .filter(|&&row| row == DisplayRow::Line(index))
                .count(),
            1
        );
    }
}

#[test]
fn zero_context_boundaries_adjacent_changes_and_touching_ranges() {
    let mut state = excerpt_state(60, &[0, 1, 30, 59]);
    state.set_context_options(0, 15);
    assert_eq!(state.excerpt_ranges, [(0, 2), (30, 31), (59, 60)]);
    assert_eq!(
        state.display_rows,
        [
            DisplayRow::Line(0),
            DisplayRow::Line(1),
            DisplayRow::Fold { start: 2, end: 30 },
            DisplayRow::Line(30),
            DisplayRow::Fold { start: 31, end: 59 },
            DisplayRow::Line(59),
        ]
    );
    assert_eq!(excerpt_state(60, &[20, 41]).excerpt_ranges, [(10, 52)]);
    assert_eq!(
        excerpt_state(3, &[0, 1, 2]).display_rows,
        [
            DisplayRow::Line(0),
            DisplayRow::Line(1),
            DisplayRow::Line(2),
        ]
    );
}

#[test]
fn expansion_anchors_source_rows_merges_and_clamps_both_directions() {
    let mut state = excerpt_state(100, &[30, 70]);
    state.top = 11;
    state.handle(Input::Char('['));
    assert_eq!(state.excerpt_ranges, [(5, 41), (60, 81)]);
    assert_eq!(state.display_rows[state.top], DisplayRow::Line(30));
    state.handle(Input::Char('['));
    assert_eq!(state.excerpt_ranges, [(0, 41), (60, 81)]);
    state.handle(Input::Char(']'));
    assert_eq!(state.excerpt_ranges, [(0, 56), (60, 81)]);
    state.handle(Input::Char(']'));
    assert_eq!(state.excerpt_ranges, [(0, 81)]);
    assert_eq!(state.display_rows[state.top], DisplayRow::Line(30));
    state.handle(Input::Char(']'));
    assert_eq!(state.excerpt_ranges, [(0, 96)]);
    state.handle(Input::Char(']'));
    state.handle(Input::Char(']'));
    assert_eq!(state.excerpt_ranges, [(0, 100)]);
    assert_eq!(state.display_rows[state.top], DisplayRow::Line(30));
}

#[test]
fn folds_choose_following_excerpt_or_previous_at_end() {
    let mut state = excerpt_state(100, &[30, 70]);
    state.handle(Input::Char('['));
    assert_eq!(state.display_rows[state.top], DisplayRow::Line(5));
    state.top = state
        .display_rows
        .iter()
        .position(|&row| row == (DisplayRow::Fold { start: 41, end: 60 }))
        .unwrap();
    state.handle(Input::Char('['));
    assert_eq!(state.excerpt_ranges, [(5, 41), (45, 81)]);
    assert_eq!(state.display_rows[state.top], DisplayRow::Line(45));
    state.handle(Input::End);
    state.handle(Input::Char(']'));
    assert_eq!(state.excerpt_ranges, [(5, 41), (45, 96)]);
    assert_eq!(state.display_rows[state.top], DisplayRow::Line(81));
}

#[test]
fn navigation_uses_display_length_and_custom_increment() {
    let mut state = excerpt_state(100, &[30]);
    state.handle(Input::End);
    state.handle(Input::Down);
    assert_eq!(state.top, 22);
    state.handle(Input::Up);
    assert_eq!(state.top, 21);
    state.handle(Input::Home);
    state.handle(Input::Up);
    assert_eq!(state.top, 0);
    state.set_context_options(0, 2);
    state.handle(Input::Char('['));
    assert_eq!(state.excerpt_ranges, [(28, 31)]);
    assert_eq!(state.display_rows[state.top], DisplayRow::Line(28));
    state.handle(Input::Char(']'));
    assert_eq!(state.excerpt_ranges, [(28, 33)]);
}

#[test]
fn metadata_empty_and_wholly_added_removed_files_preserve_alignment() {
    let mut state = DiffState::new();
    let mut comparison = comparison();
    comparison.files[0].hunks.clear();
    comparison.files[0].after = comparison.files[0].before.clone();
    state.comparison = Some(comparison);
    state.align_file();
    assert!(state.excerpt_ranges.is_empty());
    assert!(state.display_rows.is_empty());
    assert_eq!(state.rows.len(), 5);
    state.file = 1;
    state.align_file();
    assert_eq!(
        state.display_rows,
        [DisplayRow::Line(0), DisplayRow::Line(1)]
    );
    assert!(
        state
            .rows
            .iter()
            .all(|row| row.kind == RowKind::Added && row.before.is_none())
    );
    let file = &mut state.comparison.as_mut().unwrap().files[1];
    std::mem::swap(&mut file.before, &mut file.after);
    file.hunks[0].before_len = 2;
    file.hunks[0].after_len = 0;
    state.align_file();
    assert_eq!(
        state.display_rows,
        [DisplayRow::Line(0), DisplayRow::Line(1)]
    );
    assert!(
        state
            .rows
            .iter()
            .all(|row| row.kind == RowKind::Removed && row.after.is_none())
    );
    state.file = 2;
    state.align_file();
    assert!(state.rows.is_empty());
    assert!(state.display_rows.is_empty());
    assert!(state.comparison.as_ref().unwrap().files[2].notice.is_some());
}

fn revision(
    target: RevisionTarget,
    label: &str,
    description: &str,
    category: Category,
) -> Revision {
    Revision {
        target,
        label: label.into(),
        description: description.into(),
        category,
    }
}

fn catalog() -> Catalog {
    Catalog {
        kind: RepoKind::Git,
        entries: vec![
            revision(
                RevisionTarget::Working,
                "Working checkout",
                "",
                Category::Commits,
            ),
            revision(
                RevisionTarget::Commit("abcdef123".into()),
                "abcdef123",
                "Fix 界 e\u{301}",
                Category::Commits,
            ),
            revision(
                RevisionTarget::Commit("fedcba321".into()),
                "fedcba321",
                "Another change",
                Category::Commits,
            ),
            revision(
                RevisionTarget::FetchRemote("origin".into()),
                "Load history from origin",
                "",
                Category::Commits,
            ),
            revision(
                RevisionTarget::Commit("branch-tip".into()),
                "topic/branch",
                "",
                Category::Branches,
            ),
            revision(
                RevisionTarget::Remote {
                    remote: "origin".into(),
                    reference: "refs/heads/topic".into(),
                },
                "topic@origin",
                "",
                Category::Branches,
            ),
            revision(
                RevisionTarget::Commit("tag-tip".into()),
                "release",
                "",
                Category::Tags,
            ),
        ],
        notice: None,
    }
}

fn pull_page(closed: bool, rows: &[(u64, &str, &str)], has_more: bool) -> Outcome {
    Outcome::PullRequestPage {
        closed,
        result: Ok(PullRequestPage {
            kind: RepoKind::Git,
            remote: "origin".into(),
            has_more,
            entries: rows
                .iter()
                .map(|&(number, title, date)| {
                    (
                        revision(
                            RevisionTarget::PullRequest {
                                remote: "origin".into(),
                                number,
                            },
                            &format!("#{number} {title}"),
                            "Alice · main ← topic",
                            if closed {
                                Category::Closed
                            } else {
                                Category::Open
                            },
                        ),
                        date.into(),
                    )
                })
                .collect(),
        }),
    }
}

#[test]
fn pull_request_categories_keep_query_and_select_loaded_rows_before_completion() {
    let mut state = DiffState::pull_requests("origin".into());
    assert_eq!(
        state.categories(),
        [Category::Open, Category::Closed, Category::All]
    );
    state.take_request();
    state.handle(Input::Char('\t'));
    for ch in "FIX üni Alice".chars() {
        state.handle(Input::Char(ch));
    }
    state.apply_result(
        1,
        Ok(pull_page(
            true,
            &[(2, "Fix Ünicode", "2026-01-02T00:00:00Z")],
            true,
        )),
    );
    assert!(state.loading);
    assert!(state.pull_request_partial());
    assert_eq!(state.entries().next().unwrap().label, "#2 Fix Ünicode");
    state.handle(Input::Char('\t'));
    state.apply_result(
        1,
        Ok(pull_page(
            false,
            &[
                (1, "Fix Ünicode", "2026-01-03T00:00:00Z"),
                (3, "Other work", "2026-01-01T00:00:00Z"),
            ],
            true,
        )),
    );
    assert_eq!(
        state
            .entries()
            .map(|entry| entry.label.as_str())
            .collect::<Vec<_>>(),
        ["#1 Fix Ünicode", "#2 Fix Ünicode"]
    );
    state.handle(Input::Char('\t'));
    assert_eq!(state.query, "FIX üni Alice");
    state.comparison_mode = ComparisonMode::Snapshots;
    state.handle(Input::Enter);
    assert_eq!(state.phase, Phase::After);
    assert!(state.before.is_none() && state.after.is_none());
    assert_eq!(state.comparison_mode, ComparisonMode::BranchChanges);
    assert!(matches!(
        state.take_request(),
        Some(Operation::ResolvePullRequest(Revision {
            target: RevisionTarget::PullRequest { number: 1, .. },
            ..
        }))
    ));
}

#[test]
fn pull_request_all_streams_sort_deduplicate_and_preserve_selection_identity() {
    let mut state = DiffState::pull_requests("origin".into());
    state.take_request();
    state.handle(Input::BackTab);
    state.apply_result(
        1,
        Ok(pull_page(
            false,
            &[
                (1, "First", "2026-01-01T00:00:00Z"),
                (2, "Second", "2026-01-02T00:00:00Z"),
            ],
            true,
        )),
    );
    state.handle(Input::End);
    assert_eq!(
        state.entries().nth(state.selected).unwrap().label,
        "#1 First"
    );
    state.apply_result(1, Ok(pull_page(true, &[], true)));
    assert!(state.pull_request_partial());
    state.apply_result(
        1,
        Ok(pull_page(
            true,
            &[(3, "Newest", "2026-01-03T00:00:00Z")],
            true,
        )),
    );
    assert_eq!(
        state.entries().nth(state.selected).unwrap().label,
        "#1 First"
    );
    state.apply_result(
        1,
        Ok(pull_page(
            false,
            &[(2, "Second updated", "2026-01-02T00:00:00Z")],
            false,
        )),
    );
    assert_eq!(state.entries().len(), 3);
    assert_eq!(
        state
            .entries()
            .map(|entry| entry.label.as_str())
            .collect::<Vec<_>>(),
        ["#3 Newest", "#2 Second updated", "#1 First"]
    );
    assert!(state.pull_request_partial());
    state.apply_result(1, Ok(pull_page(true, &[], false)));
    assert!(!state.pull_request_partial());
    assert!(!state.loading);
    assert_eq!(
        state.entries().nth(state.selected).unwrap().label,
        "#1 First"
    );
}

#[test]
fn pull_request_late_category_errors_retry_without_losing_rows_or_other_results() {
    let mut editor = editor();
    editor.execute("pull_requests origin");
    let (id, _) = editor.take_diff_request().unwrap();
    editor.apply_diff_result(
        id,
        Ok(pull_page(
            false,
            &[(1, "Open", "2026-01-01T00:00:00Z")],
            true,
        )),
    );
    editor.apply_diff_result(
        id,
        Ok(pull_page(
            true,
            &[(2, "Closed", "2026-01-02T00:00:00Z")],
            true,
        )),
    );
    editor.handle(Input::Char('\t'));
    editor.apply_diff_result(
        id,
        Ok(Outcome::PullRequestPage {
            closed: true,
            result: Err("offline".into()),
        }),
    );
    let diff = editor.diff().unwrap();
    assert!(diff.pull_request_notice().unwrap().contains("offline"));
    assert_eq!(diff.entries().next().unwrap().label, "#2 Closed");
    assert!(diff.pull_request_partial());
    editor.handle(Input::Ctrl('r'));
    assert_eq!(editor.diff().unwrap().pull_request_retries, [0, 1]);
    assert!(editor.take_diff_request().is_none());
    editor.apply_diff_result(
        id,
        Ok(pull_page(
            false,
            &[(3, "More open", "2026-01-03T00:00:00Z")],
            false,
        )),
    );
    assert_eq!(
        editor.diff().unwrap().entries().next().unwrap().label,
        "#2 Closed"
    );
    editor.apply_diff_result(id, Ok(pull_page(true, &[], false)));
    assert!(!editor.diff().unwrap().pull_request_partial());
    editor.handle(Input::Enter);
    let (_, operation) = editor.take_diff_request().unwrap();
    assert!(matches!(operation, Operation::ResolvePullRequest(_)));
    assert!(!editor.apply_diff_result(id, Ok(pull_page(false, &[], false))));
}

#[test]
fn pull_request_loading_retry_escape_and_reopen_reject_stale_results() {
    let mut editor = editor();
    editor
        .apply(vec![Effect::Replace("unsaved source".into())])
        .unwrap();
    editor.execute("pull_requests origin");
    let (first, _) = editor.take_diff_request().unwrap();
    editor.handle(Input::Enter);
    assert!(editor.take_diff_request().is_none());
    text(&mut editor, "alice");
    editor.apply_diff_result(
        first,
        Ok(Outcome::PullRequestPage {
            closed: false,
            result: Err("API unavailable".into()),
        }),
    );
    editor.handle(Input::Enter);
    assert_eq!(editor.diff().unwrap().pull_request_retries, [1, 0]);
    assert!(editor.take_diff_request().is_none());
    assert!(editor.apply_diff_result(
        first,
        Ok(pull_page(
            false,
            &[
                (1, "Open", "2026-01-02T00:00:00Z"),
                (2, "Other open", "2026-01-01T00:00:00Z"),
            ],
            true
        ))
    ));
    editor.handle(Input::Enter);
    let (resolve, operation) = editor.take_diff_request().unwrap();
    assert!(matches!(operation, Operation::ResolvePullRequest(_)));
    assert!(!editor.apply_diff_result(first, Ok(pull_page(true, &[], false))));
    editor.apply_diff_result(resolve, Err("Historical head no longer retained".into()));
    assert!(editor.diff().unwrap().before.is_none());
    assert!(editor.diff().unwrap().after.is_none());
    editor.handle(Input::Down);
    editor.handle(Input::Enter);
    let (retry, operation) = editor.take_diff_request().unwrap();
    assert!(matches!(
        operation,
        Operation::ResolvePullRequest(Revision {
            target: RevisionTarget::PullRequest { number: 2, .. },
            ..
        })
    ));
    editor.handle(Input::Escape);
    assert!(editor.diff().is_none());
    assert!(!editor.apply_diff_result(retry, Ok(Outcome::Comparison(comparison()))));
    assert_eq!(editor.lines(), ["unsaved source"]);
    assert!(editor.dirty());
    editor.execute("pull_requests");
    let (reopened, _) = editor.take_diff_request().unwrap();
    assert!(!editor.apply_diff_result(first, Ok(pull_page(false, &[], false))));
    assert!(editor.apply_diff_result(reopened, Ok(pull_page(false, &[], false))));
    assert!(editor.apply_diff_result(reopened, Ok(pull_page(true, &[], false))));
    editor.handle(Input::Enter);
    assert!(editor.take_diff_request().is_none());
}

#[test]
fn resolved_pull_request_modes_reuse_pinned_endpoints_without_resolving_again() {
    let mut state = DiffState::pull_requests("origin".into());
    state.take_request();
    state.apply_result(
        1,
        Ok(pull_page(
            false,
            &[(1, "Open", "2026-01-01T00:00:00Z")],
            true,
        )),
    );
    state.handle(Input::Enter);
    state.take_request();
    let before = revision(
        RevisionTarget::RemoteCommit {
            remote: "origin".into(),
            reference: "refs/heads/main".into(),
            id: "base-sha".into(),
        },
        "main",
        "",
        Category::Open,
    );
    let after = revision(
        RevisionTarget::RemoteCommit {
            remote: "origin".into(),
            reference: "refs/pull/1/head".into(),
            id: "head-sha".into(),
        },
        "#1 Open",
        "",
        Category::Open,
    );
    state.apply_result(
        2,
        Ok(Outcome::ResolvedPullRequest {
            before: before.clone(),
            after: after.clone(),
        }),
    );
    assert!(matches!(
        state.take_request(),
        Some(Operation::Compare {
            mode: ComparisonMode::BranchChanges,
            ..
        })
    ));
    state.apply_result(3, Err("No common ancestor".into()));
    assert_eq!(state.before.as_ref(), Some(&before));
    assert_eq!(state.after.as_ref(), Some(&after));
    state.toggle_comparison_mode().unwrap();
    let Some(Operation::Compare {
        before: pinned_before,
        after: pinned_after,
        mode,
        ..
    }) = state.take_request()
    else {
        panic!("expected ordinary pinned comparison");
    };
    assert_eq!(
        (pinned_before, pinned_after, mode),
        (before, after, ComparisonMode::Snapshots)
    );
}

fn editor() -> Editor {
    Editor::open(None, vec![]).unwrap()
}

fn open(editor: &mut Editor) {
    assert!(editor.execute("diff").is_none());
    let (id, operation) = editor.take_diff_request().unwrap();
    assert!(matches!(operation, Operation::Discover));
    assert!(editor.apply_diff_result(id, Ok(Outcome::Catalog(catalog()))));
}

fn text(editor: &mut Editor, text: &str) {
    for ch in text.chars() {
        editor.handle(Input::Char(ch));
    }
}

fn choose_pair(editor: &mut Editor) -> u64 {
    editor.handle(Input::Down);
    editor.handle(Input::Enter);
    assert_eq!(editor.diff().unwrap().phase, Phase::After);
    editor.handle(Input::Enter);
    let (id, operation) = editor.take_diff_request().unwrap();
    match operation {
        Operation::Compare { before, after, .. } => {
            assert_eq!(before.target, RevisionTarget::Commit("abcdef123".into()));
            assert_eq!(after.target, RevisionTarget::Working);
        }
        _ => panic!("expected compare"),
    }
    id
}

fn comparison() -> Comparison {
    Comparison {
        revisions: ["abcdef123".into(), "working:snapshot".into()],
        before: "abcdef123".into(),
        after: "Working checkout".into(),
        root: PathBuf::new(),
        editable_paths: BTreeSet::new(),
        files: vec![
            ChangedFile {
                path: "renamed.txt".into(),
                old_path: Some("old.txt".into()),
                status: FileStatus::Renamed,
                loaded: true,
                before: vec![
                    "same".into(),
                    "old".into(),
                    "tail".into(),
                    "deleted".into(),
                    "end".into(),
                ],
                after: vec![
                    "same".into(),
                    "new".into(),
                    "extra".into(),
                    "tail".into(),
                    "end".into(),
                ],
                before_eof: false,
                after_eof: false,
                hunks: vec![
                    Hunk {
                        before_start: 1,
                        before_len: 1,
                        after_start: 1,
                        after_len: 2,
                    },
                    Hunk {
                        before_start: 3,
                        before_len: 1,
                        after_start: 4,
                        after_len: 0,
                    },
                ],
                notice: None,
            },
            ChangedFile {
                path: "added.txt".into(),
                old_path: None,
                status: FileStatus::Added,
                loaded: true,
                before: vec![],
                after: vec!["a".into(), "b".into()],
                before_eof: false,
                after_eof: false,
                hunks: vec![Hunk {
                    before_start: 0,
                    before_len: 0,
                    after_start: 0,
                    after_len: 2,
                }],
                notice: None,
            },
            ChangedFile {
                path: "removed.bin".into(),
                old_path: None,
                status: FileStatus::Removed,
                loaded: true,
                before: vec![],
                after: vec![],
                before_eof: false,
                after_eof: false,
                hunks: vec![],
                notice: Some("Binary file".into()),
            },
        ],
    }
}

#[test]
fn status_layout_cycles_only_present_panes_and_normalizes_selection() {
    let mut state = live_state(vec!["old".into()], vec!["new".into()], true);
    state.comparison = Some(comparison());
    state.files = Some(FilePicker::from_paths(
        PathBuf::new(),
        [
            (0, "renamed.txt".into()),
            (1, "added.txt".into()),
            (2, "removed.bin".into()),
        ],
    ));
    for (path, layout, first, last) in [
        (
            "renamed.txt",
            PaneLayout::Split,
            Focus::Before,
            Focus::After,
        ),
        ("added.txt", PaneLayout::After, Focus::After, Focus::After),
        (
            "removed.bin",
            PaneLayout::Before,
            Focus::Before,
            Focus::Before,
        ),
    ] {
        state.files_visible = true;
        state.focus = Focus::Files;
        assert!(state.select_file(Path::new(path)));
        assert_eq!(state.pane_layout(), layout);
        state.handle(Input::Char('\t'));
        assert_eq!(state.focus, first);
        state.handle(Input::BackTab);
        assert_eq!(state.focus, Focus::Files);
        state.handle(Input::BackTab);
        assert_eq!(state.focus, last);
        state.handle(Input::Char('\t'));
        assert_eq!(state.focus, Focus::Files);
        state.files_visible = false;
        state.normalize_focus();
        assert_eq!(state.focus, first);
        state.handle(Input::BackTab);
        assert_eq!(state.focus, last);
        state.handle(Input::Char('\t'));
        assert_eq!(state.focus, first);
    }
    state.focus = Focus::Before;
    assert!(state.select_file(Path::new("added.txt")));
    assert_eq!(state.focus, Focus::After);
    assert!(state.select_file(Path::new("removed.bin")));
    assert_eq!(state.focus, Focus::Before);
    assert!(state.select_file(Path::new("renamed.txt")));
    assert_eq!(state.focus, Focus::Before);
}

#[test]
fn rename_layout_and_editability_include_eof_changes() {
    let mut state = live_state(vec!["same".into()], vec!["same".into()], true);
    state.comparison.as_mut().unwrap().files[0].status = FileStatus::Renamed;
    assert_eq!(state.pane_layout(), PaneLayout::Empty);
    assert!(!state.after_editable());
    state.normalize_focus();
    assert_eq!(state.focus, Focus::Before);
    state.files_visible = false;
    for input in [Input::Char('\t'), Input::BackTab] {
        state.handle(input);
        assert_eq!(state.focus, Focus::Before);
    }
    state.comparison.as_mut().unwrap().files[0].after_eof = false;
    assert_eq!(state.pane_layout(), PaneLayout::Split);
    assert!(state.after_editable());
    state.comparison.as_mut().unwrap().files[0].after[0] = "changed".into();
    assert!(state.after_editable());
    state.comparison.as_mut().unwrap().files[0].status = FileStatus::Removed;
    assert!(!state.after_editable());
    state.comparison.as_mut().unwrap().files[0].status = FileStatus::Added;
    assert!(state.after_editable());
    let file = &mut state.comparison.as_mut().unwrap().files[0];
    file.before.clear();
    file.after.clear();
    file.notice = Some("empty file".into());
    state.normalize_focus();
    assert_eq!(state.pane_layout(), PaneLayout::After);
    assert_eq!(state.focus, Focus::After);
    assert!(state.after_editable());
    assert_eq!(
        state.comparison.as_ref().unwrap().files[0]
            .notice
            .as_deref(),
        Some("empty file")
    );
}

#[test]
fn opening_diff_file_focuses_after_when_present() {
    for view_mode in [ViewMode::Split, ViewMode::Unified] {
        for presentation in [FilePresentation::Docked, FilePresentation::Floating] {
            for status in [
                FileStatus::Modified,
                FileStatus::Renamed,
                FileStatus::Added,
                FileStatus::Removed,
            ] {
                let mut editor = editor();
                editor.set_diff_display_options(view_mode, crate::panes::SplitAxis::Vertical);
                open(&mut editor);
                let id = choose_pair(&mut editor);
                let mut changes = comparison();
                let index = match status {
                    FileStatus::Modified | FileStatus::Renamed => 0,
                    FileStatus::Added => 1,
                    FileStatus::Removed => 2,
                };
                let mut file = changes.files.remove(index);
                file.status = status;
                let expected_text = file.after.join("\n");
                changes.files = vec![file];
                editor.apply_diff_result(id, Ok(Outcome::Comparison(changes)));
                if presentation == FilePresentation::Floating {
                    text(&mut editor, " o");
                }
                editor.handle(Input::Enter);
                let diff = editor.diff().unwrap();
                assert_eq!(
                    diff.focus,
                    if status == FileStatus::Removed {
                        Focus::Before
                    } else {
                        Focus::After
                    },
                    "{view_mode:?} {presentation:?} {status:?}",
                );
                assert!(!diff.files.as_ref().unwrap().focused);
                assert_eq!(diff.files_visible, presentation == FilePresentation::Docked);
                if status != FileStatus::Removed {
                    assert_eq!(editor.context().text, expected_text);
                }
            }
        }
    }
}

#[test]
fn added_file_picker_cancel_close_and_mouse_focus_use_after() {
    let mut editor = editor();
    open(&mut editor);
    let id = choose_pair(&mut editor);
    let mut changes = comparison();
    changes.files = vec![changes.files.remove(1)];
    editor.apply_diff_result(id, Ok(Outcome::Comparison(changes)));
    editor.handle(Input::Escape);
    assert_eq!(editor.diff().unwrap().focus, Focus::After);
    text(&mut editor, " e");
    editor.handle(Input::Ctrl('w'));
    assert_eq!(editor.diff().unwrap().focus, Focus::After);
    assert!(!editor.diff().unwrap().files_visible);
    editor.scroll_diff(Focus::Before, true);
    assert_eq!(editor.diff().unwrap().focus, Focus::After);
    editor.handle(Input::BackTab);
    assert_eq!(editor.diff().unwrap().focus, Focus::After);
}

#[test]
fn revision_matches_rank_later_contiguous_boundaries_and_tight_subsequences() {
    assert_eq!(fuzzy_match("r---f---s/topic/rfs", "rfs").unwrap()[0], 2);
    assert!(fuzzy_match("topic/rfs", "rfs") < fuzzy_match("topicxrfs", "rfs"));
    assert!(fuzzy_match("r-f-s", "rfs") < fuzzy_match("r---f---s", "rfs"));
    assert!(fuzzy_match("über-parser", "üpr").is_some());
    assert!(fuzzy_match("parser", "srp").is_none());
}

#[test]
fn jujutsu_fuzzy_selectors_rank_labels_above_descriptions_in_both_stages() {
    for phase in [Phase::Before, Phase::After] {
        for (category_index, &category) in RepoKind::Jujutsu.categories().iter().enumerate() {
            let mut state = DiffState::new();
            state.apply_result(
                1,
                Ok(Outcome::Catalog(Catalog {
                    kind: RepoKind::Jujutsu,
                    entries: vec![
                        revision(
                            RevisionTarget::Working,
                            "Working checkout",
                            "",
                            Category::Revisions,
                        ),
                        revision(
                            RevisionTarget::Commit("description-target".into()),
                            "unrelated",
                            "sm/fin-1205-pilot-assignment-schema",
                            category,
                        ),
                        revision(
                            RevisionTarget::Commit("immutable-fuzzy-target".into()),
                            "sm/fin-1205-pilot-assignment-schema",
                            "",
                            category,
                        ),
                        revision(
                            RevisionTarget::Commit("immutable-exact-target".into()),
                            "f1205pas",
                            "",
                            category,
                        ),
                    ],
                    notice: None,
                })),
            );
            state.phase = phase;
            state.category = category_index;
            state.query = "F1205PAS".into();
            state.refilter();
            assert_eq!(
                state
                    .entries()
                    .skip(1)
                    .map(|entry| &entry.target)
                    .collect::<Vec<_>>(),
                [
                    &RevisionTarget::Commit("immutable-exact-target".into()),
                    &RevisionTarget::Commit("immutable-fuzzy-target".into()),
                    &RevisionTarget::Commit("description-target".into()),
                ]
            );
        }
    }
}

#[test]
fn selector_filters_literal_unicode_tokens_and_pins_working_in_each_category() {
    let mut editor = editor();
    open(&mut editor);
    text(&mut editor, "FIX 界 e\u{301}");
    assert_eq!(
        editor
            .diff()
            .unwrap()
            .entries()
            .map(|entry| entry.label.as_str())
            .collect::<Vec<_>>(),
        ["Working checkout", "abcdef123"]
    );
    editor.handle(Input::Backspace);
    assert_eq!(editor.diff().unwrap().query, "FIX 界 ");
    editor.handle(Input::Char('\t'));
    assert_eq!(editor.diff().unwrap().category, 1);
    assert_eq!(editor.diff().unwrap().entries().len(), 1);
    editor.handle(Input::Ctrl('u'));
    assert_eq!(editor.diff().unwrap().entries().len(), 3);
    editor.handle(Input::BackTab);
    assert_eq!(editor.diff().unwrap().category, 0);
    editor.handle(Input::BackTab);
    assert_eq!(editor.diff().unwrap().category, 2);
    assert_eq!(editor.diff().unwrap().entries().len(), 2);
    editor.handle(Input::Char('\t'));
    assert_eq!(editor.diff().unwrap().category, 0);
    editor
        .bind("selection", "x", Some("core.down".into()))
        .unwrap();
    editor.handle(Input::Char('x'));
    assert_eq!(editor.diff().unwrap().selected, 1);
    assert!(editor.diff().unwrap().query.is_empty());
    editor.bind("selection", "ctrl+j", None).unwrap();
    editor.handle(Input::Ctrl('j'));
    assert_eq!(editor.diff().unwrap().selected, 1);
}

#[test]
fn selector_word_and_line_deletion_preserve_source_in_both_stages() {
    for after in [false, true] {
        let mut editor = editor();
        editor
            .apply(vec![Effect::Replace("source text".into())])
            .unwrap();
        let source = editor.context().text;
        let revision = editor.text_revision();
        let carets = editor.carets();
        open(&mut editor);
        if after {
            editor.handle(Input::Enter);
        }
        let phase = if after { Phase::After } else { Phase::Before };
        text(&mut editor, "FIX missing");
        assert_eq!(editor.diff().unwrap().entries().len(), 1);
        editor.handle(Input::AltBackspace);
        assert_eq!(editor.diff().unwrap().query, "FIX ");
        assert_eq!(editor.diff().unwrap().entries().len(), 2);
        editor.handle(Input::SuperBackspace);
        assert!(editor.diff().unwrap().query.is_empty());
        assert_eq!(
            editor
                .diff()
                .unwrap()
                .entries()
                .map(|entry| entry.label.as_str())
                .collect::<Vec<_>>(),
            [
                "Working checkout",
                "abcdef123",
                "fedcba321",
                "Load history from origin"
            ]
        );
        for input in [Input::Backspace, Input::AltBackspace, Input::SuperBackspace] {
            editor.handle(input);
        }
        assert_eq!(editor.diff().unwrap().phase, phase);
        assert_eq!(editor.context().text, source);
        assert_eq!(editor.text_revision(), revision);
        assert_eq!(editor.carets(), carets);
    }
}

#[test]
fn loader_preserves_after_step_query_category_and_selection_then_compares() {
    let mut editor = editor();
    open(&mut editor);
    editor.handle(Input::Down);
    editor.handle(Input::Enter);
    text(&mut editor, "origin");
    editor.handle(Input::Down);
    editor.handle(Input::Enter);
    let (id, operation) = editor.take_diff_request().unwrap();
    assert!(matches!(operation, Operation::FetchRemote(remote) if remote == "origin"));
    assert_eq!(editor.diff().unwrap().phase, Phase::After);
    assert!(editor.diff().unwrap().loading);
    editor.handle(Input::Enter);
    assert!(editor.take_diff_request().is_none());
    let mut loaded = catalog();
    loaded.entries.push(revision(
        RevisionTarget::Commit("remote-commit".into()),
        "remote-commit",
        "origin remote history",
        Category::Commits,
    ));
    assert!(editor.apply_diff_result(id, Ok(Outcome::Catalog(loaded))));
    let state = editor.diff().unwrap();
    assert_eq!(state.phase, Phase::After);
    assert_eq!(state.query, "origin");
    assert_eq!(state.category, 0);
    assert_eq!(
        state.entries().nth(state.selected).unwrap().target,
        RevisionTarget::FetchRemote("origin".into())
    );
    assert_eq!(state.entries().len(), 3);
    let remote_position = state
        .entries()
        .position(
            |entry| matches!(&entry.target, RevisionTarget::Commit(id) if id == "remote-commit"),
        )
        .unwrap();
    editor.handle(Input::Home);
    for _ in 0..remote_position {
        editor.handle(Input::Down);
    }
    editor.handle(Input::Enter);
    let (id, operation) = editor.take_diff_request().unwrap();
    assert!(matches!(operation, Operation::Compare { after, .. }
            if after.target == RevisionTarget::Commit("remote-commit".into())));
    assert!(editor.apply_diff_result(id, Err("comparison failed".into())));
    assert_eq!(editor.diff().unwrap().phase, Phase::After);
    assert_eq!(editor.diff().unwrap().query, "origin");
    assert!(editor.diff().unwrap().error.is_some());
    editor.handle(Input::Enter);
    assert!(matches!(
        editor.take_diff_request(),
        Some((_, Operation::Compare { .. }))
    ));
}

#[test]
fn selector_escape_closes_each_stage_and_rejects_late_results() {
    for after in [false, true] {
        let mut editor = editor();
        editor
            .apply(vec![Effect::Replace("unsaved source".into())])
            .unwrap();
        let buffer = editor.buffer_id();
        open(&mut editor);
        let request = if after {
            Some(choose_pair(&mut editor))
        } else {
            text(&mut editor, "query");
            None
        };
        editor.handle(Input::Escape);
        assert!(editor.diff().is_none());
        assert_eq!(editor.buffer_id(), buffer);
        assert_eq!(editor.lines(), ["unsaved source"]);
        assert!(editor.dirty());
        if let Some(id) = request {
            assert!(!editor.apply_diff_result(id, Ok(Outcome::Comparison(comparison()))));
            assert!(editor.diff().is_none());
        }
    }
}

#[test]
fn selector_printable_input_precedes_normal_bindings_but_not_selection_overrides() {
    for after in [false, true] {
        let mut editor = editor();
        open(&mut editor);
        if after {
            editor.handle(Input::Enter);
        }
        editor
            .bind("normal", "x", Some("core.command".into()))
            .unwrap();
        for ch in ":_| x".chars() {
            editor.handle(Input::Char(ch));
            assert_eq!(editor.mode(), Mode::Normal);
            assert_eq!(editor.pane_layout().len(), 1);
        }
        assert_eq!(editor.diff().unwrap().query, ":_| x");
        editor.handle(Input::Ctrl('u'));
        editor
            .bind("selection", ":", Some("core.down".into()))
            .unwrap();
        editor.handle(Input::Char(':'));
        assert_eq!(editor.diff().unwrap().selected, 1);
        assert!(editor.diff().unwrap().query.is_empty());
    }
    let mut editor = editor();
    open(&mut editor);
    editor.handle(Input::Ctrl('p'));
    editor.handle(Input::Char(':'));
    assert_eq!(editor.palette().unwrap().query, ":");
    assert_eq!(editor.mode(), Mode::Normal);
    editor.handle(Input::Escape);
    assert!(editor.palette().is_none());
    assert!(editor.diff().is_some());
}

#[test]
fn file_to_directory_change_opens_both_historical_paths() {
    let mut editor = editor();
    open(&mut editor);
    let id = choose_pair(&mut editor);
    let mut changes = comparison();
    changes.files[0].path = "x".into();
    changes.files[1].path = "x/y".into();
    changes.files.truncate(2);
    editor.apply_diff_result(id, Ok(Outcome::Comparison(changes)));
    let picker = editor.diff().unwrap().files.as_ref().unwrap();
    assert!(!picker.entries().nth(picker.selected).unwrap().is_dir);
    editor.handle(Input::Enter);
    assert_eq!(editor.diff().unwrap().file, 0);
    text(&mut editor, " e");
    editor.handle(Input::Char('i'));
    text(&mut editor, "x/y");
    editor.handle(Input::Enter);
    assert_eq!(editor.diff().unwrap().file, 1);
    assert_eq!(editor.diff().unwrap().focus, Focus::After);
}

#[test]
fn changed_tree_filters_navigates_and_opens_without_touching_buffers() {
    let mut editor = editor();
    let original = editor.context().text;
    let carets = editor.carets();
    let revision = editor.text_revision();
    open(&mut editor);
    let id = choose_pair(&mut editor);
    let mut changes = comparison();
    changes.files[0].path = "src/deep/renamed.txt".into();
    changes.files[1].path = "src/deep/added.txt".into();
    changes.files[2].path = "archive/gone/removed.bin".into();
    editor.apply_diff_result(id, Ok(Outcome::Comparison(changes)));
    let picker = editor.diff().unwrap().files.as_ref().unwrap();
    assert!(picker.focused && !picker.searching);
    assert_eq!(
        picker.entries().nth(picker.selected).unwrap().path,
        std::path::Path::new("src/deep/renamed.txt")
    );
    assert!(picker.entries().any(|row| row.label == "src/deep"));
    editor.bind("tree", "z", Some("core.left".into())).unwrap();
    editor.handle(Input::Char('z'));
    let picker = editor.diff().unwrap().files.as_ref().unwrap();
    assert!(picker.entries().nth(picker.selected).unwrap().is_dir);
    editor.handle(Input::Enter);
    let picker = editor.diff().unwrap().files.as_ref().unwrap();
    assert!(!picker.entries().nth(picker.selected).unwrap().expanded);
    assert_eq!(editor.diff().unwrap().file, 0);
    editor.handle(Input::Char('l'));
    editor.handle(Input::Char('l'));
    editor
        .bind("selection", "ctrl+n", Some("core.down".into()))
        .unwrap();
    editor.handle(Input::Ctrl('n'));
    assert_eq!(editor.diff().unwrap().file, 0);
    editor.handle(Input::Char('i'));
    text(&mut editor, "removed.bin");
    editor.handle(Input::Enter);
    let state = editor.diff().unwrap();
    assert_eq!(state.file, 2);
    assert_eq!(state.focus, Focus::Before);
    assert!(!state.files.as_ref().unwrap().focused);
    assert!(state.rows.is_empty());
    editor.handle(Input::BackTab);
    editor.handle(Input::Escape);
    assert!(!editor.diff().unwrap().files.as_ref().unwrap().searching);
    editor.handle(Input::Ctrl('u'));
    assert!(
        editor
            .diff()
            .unwrap()
            .files
            .as_ref()
            .unwrap()
            .query
            .is_empty()
    );
    editor.handle(Input::Ctrl('t'));
    assert_eq!(
        editor.diff().unwrap().files.as_ref().unwrap().view,
        FileView::List
    );
    editor.handle(Input::Ctrl('t'));
    assert_eq!(
        editor.diff().unwrap().files.as_ref().unwrap().view,
        FileView::Tree
    );
    editor.handle(Input::Ctrl('r'));
    editor.handle(Input::Char('i'));
    text(&mut editor, "removed.bin");
    editor.handle(Input::Enter);
    assert_eq!(editor.diff().unwrap().focus, Focus::Before);
    assert_eq!(editor.context().text, original);
    assert_eq!(editor.carets(), carets);
    assert_eq!(editor.text_revision(), revision);
    editor.handle(Input::Escape);
    assert!(editor.diff().is_some());
    editor.execute("diff.close");
    assert!(editor.diff().is_none());
}

#[test]
fn explorer_actions_preserve_review_and_ctrl_e_uses_normal_bindings() {
    let mut editor = editor();
    open(&mut editor);
    let id = choose_pair(&mut editor);
    editor.apply_diff_result(id, Ok(Outcome::Comparison(comparison())));
    editor
        .bind("tree", "ctrl+e", Some("core.down".into()))
        .unwrap();
    editor.handle(Input::Ctrl('e'));
    assert!(editor.diff().unwrap().files_visible);
    assert_eq!(
        editor
            .diff()
            .unwrap()
            .files
            .as_ref()
            .unwrap()
            .entries()
            .nth(editor.diff().unwrap().files.as_ref().unwrap().selected)
            .unwrap()
            .path,
        Path::new("added.txt")
    );
    editor.handle(Input::Ctrl('w'));
    assert!(editor.diff().is_some());
    assert!(!editor.diff().unwrap().files_visible);
    text(&mut editor, " e");
    assert!(editor.diff().unwrap().files_visible);
    assert_eq!(editor.diff().unwrap().focus, Focus::Files);
    assert_eq!(
        editor.diff().unwrap().files.as_ref().unwrap().presentation,
        crate::files::FilePresentation::Docked
    );
    editor.handle(Input::Ctrl('w'));
    text(&mut editor, " o");
    assert_eq!(
        editor.diff().unwrap().files.as_ref().unwrap().presentation,
        crate::files::FilePresentation::Floating
    );
    editor.handle(Input::Escape);
    editor.handle(Input::Escape);
    assert!(editor.diff().is_some());
    editor.execute("diff.close");
    assert!(editor.diff().is_none());
}

#[test]
fn explorer_toggle_is_not_a_revision_selector_control() {
    let mut editor = editor();
    open(&mut editor);
    editor.handle(Input::Ctrl('e'));
    assert_eq!(editor.diff().unwrap().selected, 0);
    editor
        .bind("selection", "ctrl+e", Some("core.down".into()))
        .unwrap();
    for phase in [Phase::Before, Phase::After] {
        assert_eq!(editor.diff().unwrap().phase, phase);
        editor.handle(Input::Ctrl('e'));
        let state = editor.diff().unwrap();
        assert!(state.files_visible);
        assert_eq!(state.selected, 1);
        assert_eq!(state.phase, phase);
        editor.handle(Input::Enter);
    }
}

#[test]
fn aligned_hunks_navigation_shared_top_independent_horizontal_and_file_reset() {
    let mut editor = editor();
    open(&mut editor);
    let id = choose_pair(&mut editor);
    assert!(editor.apply_diff_result(id, Ok(Outcome::Comparison(comparison()))));
    assert_eq!(
        editor
            .diff()
            .unwrap()
            .rows
            .iter()
            .map(|row| (row.before, row.after, row.kind))
            .collect::<Vec<_>>(),
        [
            (Some(0), Some(0), RowKind::Equal),
            (Some(1), Some(1), RowKind::Changed),
            (None, Some(2), RowKind::Added),
            (Some(2), Some(3), RowKind::Equal),
            (Some(3), None, RowKind::Removed),
            (Some(4), Some(4), RowKind::Equal),
        ]
    );
    editor.handle(Input::Char('\t'));
    assert_eq!(editor.diff().unwrap().focus, Focus::Before);
    editor.handle(Input::Down);
    editor.handle(Input::Right);
    assert_eq!(editor.cursor().row, 1);
    assert_eq!(editor.cursor().column, 1);
    editor.scroll_diff(Focus::Before, true);
    editor.set_diff_viewport(id, 0, 1, 1, 0);
    editor.handle(Input::Char('\t'));
    assert_eq!(editor.diff().unwrap().focus, Focus::After);
    editor.handle(Input::Down);
    editor.handle(Input::Right);
    assert_eq!(editor.cursor().row, 2);
    assert_eq!(editor.diff().unwrap().top, 1);
    editor.set_diff_viewport(id, 0, 2, 1, 1);
    assert_eq!(editor.diff().unwrap().left_after, 1);
    assert_eq!(editor.diff().unwrap().left_before, 1);
    editor.handle(Input::End);
    assert_eq!(editor.diff().unwrap().top, 2);
    editor.handle(Input::BackTab);
    assert_eq!(editor.diff().unwrap().focus, Focus::Before);
    editor.handle(Input::BackTab);
    editor.handle(Input::Down);
    assert_eq!(editor.diff().unwrap().file, 0);
    editor.handle(Input::Enter);
    let state = editor.diff().unwrap();
    assert_eq!(state.file, 1);
    assert_eq!((state.top, state.left_before, state.left_after), (0, 0, 0));
    assert!(
        state
            .rows
            .iter()
            .all(|row| row.before.is_none() && row.kind == RowKind::Added)
    );
    editor.handle(Input::BackTab);
    editor.handle(Input::Down);
    editor.handle(Input::Enter);
    assert_eq!(editor.diff().unwrap().file, 2);
    assert!(editor.diff().unwrap().rows.is_empty());
    assert!(
        editor.diff().unwrap().comparison.as_ref().unwrap().files[2]
            .notice
            .is_some()
    );
    editor.handle(Input::BackTab);
    editor.handle(Input::Down);
    editor.handle(Input::Enter);
    assert_eq!(editor.diff().unwrap().file, 0);
}

#[test]
fn comparison_identity_comes_from_accepted_requests_not_working_labels() {
    let mut editor = editor();
    open(&mut editor);
    let first = choose_pair(&mut editor);
    assert!(editor.apply_diff_result(first, Ok(Outcome::Comparison(comparison()))));
    assert_eq!(editor.diff().unwrap().comparison_id, Some(first));
    editor.execute("diff.close");
    open(&mut editor);
    assert_eq!(editor.diff().unwrap().comparison_id, None);
    let second = choose_pair(&mut editor);
    assert!(second > first);
    assert!(!editor.apply_diff_result(first, Ok(Outcome::Comparison(comparison()))));
    assert_eq!(editor.diff().unwrap().comparison_id, None);
    assert!(editor.apply_diff_result(second, Ok(Outcome::Comparison(comparison()))));
    assert_eq!(editor.diff().unwrap().comparison_id, Some(second));
}

#[test]
fn closing_diff_rejects_pending_file_details_even_after_reopening() {
    let mut editor = editor();
    open(&mut editor);
    let comparison_id = choose_pair(&mut editor);
    let mut catalog = comparison();
    let detail = catalog.files.remove(0);
    catalog.files.clear();
    catalog.files.push(ChangedFile {
        path: detail.path.clone(),
        old_path: detail.old_path.clone(),
        status: detail.status,
        loaded: false,
        before: vec![],
        after: vec![],
        before_eof: false,
        after_eof: false,
        hunks: vec![],
        notice: None,
    });
    editor.apply_diff_result(comparison_id, Ok(Outcome::Comparison(catalog)));
    let (file_request, _) = editor.take_diff_request().unwrap();
    editor.execute("diff.close");
    assert!(!editor.apply_diff_result(
        file_request,
        Ok(Outcome::File {
            comparison_id,
            file_index: 0,
            file: detail,
        })
    ));
    assert!(editor.diff().is_none());
    open(&mut editor);
    assert!(editor.diff().unwrap().comparison.is_none());
}

#[test]
fn explicit_remote_ref_loader_preserves_selector_position_without_choosing_revision() {
    let mut state = DiffState::new();
    let mut initial = catalog();
    let loader = initial
        .entries
        .iter_mut()
        .find(|entry| matches!(entry.target, RevisionTarget::FetchRemote(_)))
        .unwrap();
    loader.target = RevisionTarget::ListRemote("origin".into());
    loader.label = "Load refs from origin".into();
    state.apply_result(1, Ok(Outcome::Catalog(initial)));
    state.phase = Phase::After;
    state.query = "origin".into();
    state.refilter();
    state.selected = 1;
    state.choose();
    assert!(
        matches!(state.take_request(), Some(Operation::ListRemote(remote)) if remote == "origin")
    );
    let mut loaded = catalog();
    let loader = loaded
        .entries
        .iter_mut()
        .find(|entry| matches!(entry.target, RevisionTarget::FetchRemote(_)))
        .unwrap();
    loader.target = RevisionTarget::ListRemote("origin".into());
    loader.label = "Load refs from origin".into();
    loaded.entries.push(revision(
        RevisionTarget::Remote {
            remote: "origin".into(),
            reference: "refs/heads/new".into(),
        },
        "new@origin",
        "",
        Category::Branches,
    ));
    state.apply_result(2, Ok(Outcome::Catalog(loaded)));
    assert_eq!(state.phase, Phase::After);
    assert_eq!(state.query, "origin");
    assert_eq!(state.category, 0);
    assert_eq!(state.selected, 1);
    assert!(state.after.is_none());
    assert!(!state.loading);
    state.category = 1;
    state.refilter();
    assert!(
        state
            .entries()
            .any(|entry| matches!(entry.target, RevisionTarget::Remote { .. }))
    );
}

#[test]
fn discovery_and_fetch_errors_are_retryable_and_stale_responses_cannot_reopen() {
    let mut editor = editor();
    editor.execute("diff");
    let (old, _) = editor.take_diff_request().unwrap();
    editor.handle(Input::Escape);
    assert!(!editor.apply_diff_result(old, Ok(Outcome::Catalog(catalog()))));
    editor.execute("diff");
    let (id, _) = editor.take_diff_request().unwrap();
    assert!(id > old);
    assert!(!editor.apply_diff_result(old, Err("stale".into())));
    assert!(editor.diff().unwrap().loading);
    assert!(editor.apply_diff_result(id, Err("discovery failed".into())));
    assert!(editor.diff().unwrap().error.is_some());
    editor.handle(Input::Enter);
    let (retry, operation) = editor.take_diff_request().unwrap();
    assert!(matches!(operation, Operation::Discover));
    assert!(retry > id);
    assert!(editor.apply_diff_result(retry, Ok(Outcome::Catalog(catalog()))));
    text(&mut editor, "origin");
    editor.handle(Input::Down);
    editor.handle(Input::Enter);
    let (fetch, _) = editor.take_diff_request().unwrap();
    assert!(editor.apply_diff_result(fetch, Err("fetch failed".into())));
    assert_eq!(editor.diff().unwrap().entries().len(), 2);
    assert_eq!(editor.diff().unwrap().query, "origin");
    editor.handle(Input::Ctrl('u'));
    editor.handle(Input::Home);
    editor.handle(Input::Enter);
    assert_eq!(editor.diff().unwrap().phase, Phase::After);
}

#[test]
fn immutable_diff_and_selectors_preserve_dirty_buffers_carets_and_undo() {
    let mut editor = editor();
    editor
        .apply(vec![Effect::Replace("original\\nsecond".into())])
        .unwrap();
    editor.handle(Input::Char('i'));
    text(&mut editor, "unsaved");
    editor.handle(Input::Escape);
    editor.handle(Input::Right);
    let original = editor.context().text;
    let carets = editor.carets();
    let revision = editor.text_revision();
    let buffers = editor
        .buffers()
        .map(|buffer| (buffer.id, buffer.dirty))
        .collect::<Vec<_>>();
    editor
        .bind("normal", "x", Some("core.diff".into()))
        .unwrap();
    assert!(editor.handle(Input::Char('x')).is_none());
    let (id, _) = editor.take_diff_request().unwrap();
    assert!(editor.apply_diff_result(id, Ok(Outcome::Catalog(catalog()))));
    for input in [
        Input::Char('i'),
        Input::Char('d'),
        Input::Delete,
        Input::Paste("bad\\n:q!".into()),
    ] {
        assert!(editor.handle(input).is_none());
    }
    assert!(editor.execute("bdelete!").is_none());
    assert!(editor.apply(vec![Effect::Replace("bad".into())]).is_err());
    assert_eq!(editor.context().text, original);
    assert_eq!(editor.carets(), carets);
    assert_eq!(editor.text_revision(), revision);
    assert_eq!(
        editor
            .buffers()
            .map(|buffer| (buffer.id, buffer.dirty))
            .collect::<Vec<_>>(),
        buffers
    );
    editor.handle(Input::Escape);
    assert!(editor.diff().is_none());
    assert_eq!(editor.mode(), Mode::Normal);
    open(&mut editor);
    let id = choose_pair(&mut editor);
    editor.apply_diff_result(id, Ok(Outcome::Comparison(comparison())));
    for input in [
        Input::Char('i'),
        Input::Char('u'),
        Input::Char('d'),
        Input::Paste("bad".into()),
        Input::Delete,
        Input::Backspace,
        Input::Enter,
    ] {
        editor.handle(input);
    }
    editor.handle(Input::Escape);
    editor.handle(Input::Escape);
    assert!(editor.diff().is_some());
    editor.execute("diff.close");
    assert_eq!(editor.context().text, original);
    assert_eq!(editor.carets(), carets);
    editor.handle(Input::Char('u'));
    assert_eq!(editor.context().text, "original\\nsecond");
}

#[test]
fn jujutsu_categories_empty_comparison_and_command_mode_entry_are_complete() {
    let mut editor = editor();
    editor.handle(Input::Char(':'));
    text(&mut editor, "diff");
    editor.handle(Input::Enter);
    assert_eq!(editor.mode(), Mode::Normal);
    let (id, _) = editor.take_diff_request().unwrap();
    let mut catalog = catalog();
    catalog.kind = RepoKind::Jujutsu;
    catalog.entries[0].category = Category::Revisions;
    catalog.entries[1].category = Category::Revisions;
    catalog.entries[4].category = Category::Bookmarks;
    assert!(editor.apply_diff_result(id, Ok(Outcome::Catalog(catalog))));
    assert_eq!(editor.diff().unwrap().entries().len(), 2);
    editor.handle(Input::Char('\t'));
    assert_eq!(
        editor.diff().unwrap().entries().nth(1).unwrap().category,
        Category::Bookmarks
    );
    editor.handle(Input::Home);
    editor.handle(Input::Enter);
    editor.handle(Input::Enter);
    let (id, _) = editor.take_diff_request().unwrap();
    assert!(editor.apply_diff_result(
        id,
        Ok(Outcome::Comparison(Comparison {
            revisions: ["working:snapshot".into(), "working:snapshot".into()],
            before: "Working".into(),
            after: "Working".into(),
            files: vec![],
            root: PathBuf::new(),
            editable_paths: BTreeSet::new(),
        }))
    ));
    assert_eq!(editor.diff().unwrap().phase, Phase::View);
    assert!(editor.diff().unwrap().rows.is_empty());
    for input in [Input::Down, Input::End, Input::Up, Input::Right, Input::End] {
        editor.handle(input);
    }
    assert_eq!(editor.diff().unwrap().top, 0);
    assert_eq!(editor.diff().unwrap().file, 0);
    editor.handle(Input::Escape);
    assert!(editor.diff().is_some());
    editor.execute("diff.close");
    assert!(editor.diff().is_none());
}

fn live_state(before: Vec<String>, after: Vec<String>, eof: bool) -> DiffState {
    let mut state = DiffState::new();
    state.phase = Phase::View;
    state.focus = Focus::After;
    state.after = Some(revision(
        RevisionTarget::Working,
        "Working",
        "",
        Category::Commits,
    ));
    state.comparison = Some(Comparison {
        revisions: ["base".into(), "working:snapshot".into()],
        root: PathBuf::new(),
        before: "base".into(),
        after: "Working".into(),
        editable_paths: BTreeSet::from([PathBuf::from("file")]),
        files: vec![ChangedFile {
            path: "file".into(),
            old_path: None,
            status: FileStatus::Modified,
            hunks: line_hunks(&before, eof, &after, eof),
            before,
            after,
            before_eof: eof,
            after_eof: eof,
            notice: None,
            loaded: true,
        }],
    });
    state.files = Some(FilePicker::from_paths(
        PathBuf::new(),
        [(0, PathBuf::from("file"))],
    ));
    state.align_file();
    state
}

#[test]
fn column_view_preserves_split_gaps_unified_sides_and_folded_coordinates() {
    let mut state = live_state(
        ["head", "tail"].map(str::to_owned).to_vec(),
        ["head", "added", "tail"].map(str::to_owned).to_vec(),
        false,
    );
    let before = state.column_view(Focus::Before).unwrap();
    assert!(matches!(before.row(1), Some(ColumnRow::Gap)));
    assert_eq!(before.native_row(1), None);
    assert_eq!(before.display_row(1), Some(2));
    state.set_view_mode(ViewMode::Unified);
    let before = state.column_view(Focus::Before).unwrap();
    let ColumnRow::Text(line) = before.row(1).unwrap() else {
        panic!("unified insertion must paint the after source");
    };
    assert_eq!(
        (line.text, line.side, line.source_row),
        (Some("added"), Focus::After, 1)
    );
    assert_eq!(line.numbers, [None, Some(1)]);
    assert!(line.changed);
    assert_eq!(before.native_row(1), None);
    assert_eq!(before.review_row(Focus::Before, 1), None);
    assert_eq!(before.review_row(Focus::After, 1), Some(1));
    let ColumnRow::Text(line) = before.row(2).unwrap() else {
        panic!("equal context must contain text");
    };
    assert_eq!(line.numbers, [Some(1), Some(2)]);
    assert_eq!(before.native_row(2), Some(1));
    assert_eq!(before.review_row(Focus::Before, 2), Some(1));
    assert_eq!(before.review_row(Focus::After, 2), Some(2));
    assert_eq!(before.display_row(1), Some(2));
    for invalid in [before.info.display_len, usize::MAX] {
        assert!(before.row(invalid).is_none());
        assert_eq!(before.native_row(invalid), None);
        assert_eq!(before.review_row(Focus::After, invalid), None);
    }
    assert_eq!(before.display_row(usize::MAX), None);

    let lines: Vec<_> = (0..30).map(|row| format!("line {row}")).collect();
    let mut changed = lines.clone();
    changed[15] = "changed".into();
    let mut state = live_state(lines, changed, false);
    state.set_context_options(0, 1);
    for mode in [ViewMode::Split, ViewMode::Unified] {
        state.set_view_mode(mode);
        let view = state.column_view(Focus::After).unwrap();
        assert!(matches!(view.row(0), Some(ColumnRow::Fold { hidden: 15 })));
        assert_eq!(view.native_row(0), None);
        assert_eq!(view.review_row(Focus::After, 0), None);
        assert_eq!(view.display_row(0), None);
        let display = view.display_row(15).unwrap();
        let ColumnRow::Text(line) = view.row(display).unwrap() else {
            panic!("visible changed source must contain text");
        };
        assert_eq!((line.text, line.source_row), (Some("changed"), 15));
        assert_eq!(view.native_row(display), Some(15));
    }
}

#[test]
fn column_view_distinguishes_native_terminal_rows_from_missing_ordinary_text() {
    for text in ["", "same\n"] {
        let lines: Vec<_> = text.split('\n').map(str::to_owned).collect();
        let mut state = DiffState::new();
        state.set_resolver_text(&lines, &lines);
        for focus in [Focus::Before, Focus::After] {
            let view = state.column_view(focus).unwrap();
            let native = lines.len() - 1;
            let display = view.display_row(native).unwrap();
            let ColumnRow::Text(line) = view.row(display).unwrap() else {
                panic!("native terminal row must contain text");
            };
            assert_eq!((line.text, line.source_row), (Some(""), native));
            assert_eq!(line.newline, text.ends_with('\n'));
            assert_eq!(view.native_row(display), Some(native));
            assert_eq!(view.info.source_extents, [lines.len(); 2]);
            assert_eq!(view.info.stored_lengths, [lines.len() - 1; 2]);
        }
    }
    let mut state = live_state(vec!["old".into()], vec!["new".into()], false);
    // A mapped but unavailable ordinary source is not a synthetic terminal row.
    state.comparison.as_mut().unwrap().files[0].after.clear();
    let view = state.column_view(Focus::After).unwrap();
    let ColumnRow::Text(line) = view.row(0).unwrap() else {
        panic!("missing source text must retain its mapped row");
    };
    assert_eq!(line.text, None);
    assert_eq!(line.source_row, 0);
}

#[test]
fn column_view_suppresses_whole_file_emphasis_without_losing_change_markers() {
    let mut state = live_state(vec!["abc".into()], vec!["aXYbc".into()], false);
    for (focus, expected) in [(Focus::Before, 1..1), (Focus::After, 1..3)] {
        let view = state.column_view(focus).unwrap();
        let ColumnRow::Text(line) = view.row(0).unwrap() else {
            panic!("changed row must contain text");
        };
        assert!(line.changed && line.emphasize);
        assert_eq!(line.changes().cloned().collect::<Vec<_>>(), [expected]);
    }
    for status in [FileStatus::Added, FileStatus::Removed] {
        state.comparison.as_mut().unwrap().files[0].status = status;
        for focus in [Focus::Before, Focus::After] {
            let view = state.column_view(focus).unwrap();
            let ColumnRow::Text(line) = view.row(0).unwrap() else {
                panic!("whole-file status must retain source text");
            };
            assert!(line.changed);
            assert!(!line.emphasize);
            assert_eq!(line.changes().count(), 0);
        }
    }
}

#[test]
fn working_refresh_preserves_noops_errors_and_view_state_but_invalidates_old_identity() {
    let mut state = live_state(vec!["old".into()], vec!["new".into()], false);
    state.loading = false;
    state.pending = None;
    state.request_kind = None;
    state.comparison_id = Some(7);
    state.word_wrap = true;
    state.view_mode = ViewMode::Unified;
    state.comparison_mode = ComparisonMode::Snapshots;
    state.split_axis = crate::panes::SplitAxis::Horizontal;
    state.files_visible = false;
    state.reviewed_files.insert(0);
    state.error = Some("previous notice".into());
    let files = state.files.as_mut().unwrap();
    files.set_view(FileView::Tree);
    files.start_search();
    files.query = "file".into();
    files.refilter();
    state.queue_checkout_refresh(true);
    assert!(matches!(
        state.take_request(),
        Some(Operation::RefreshCheckout {
            comparison_id: 7,
            ..
        })
    ));
    assert!(state.apply_result(8, Ok(Outcome::CheckoutRefresh(None))));
    assert!(state.error.is_none());
    assert_eq!(state.comparison_id, Some(7));
    assert_eq!(state.reviewed_files, BTreeSet::from([0]));

    state.queue_checkout_refresh(true);
    state.take_request();
    assert!(state.apply_result(9, Err("refresh failed".into())));
    assert_eq!(state.comparison_id, Some(7));
    assert_eq!(state.comparison.as_ref().unwrap().files[0].after, ["new"]);
    assert_eq!(state.reviewed_files, BTreeSet::from([0]));
    assert_eq!(state.error.as_deref(), Some("refresh failed"));

    state.queue_checkout_refresh(true);
    state.take_request();
    let mut replacement = live_state(vec!["old".into()], vec!["ahead".into()], false)
        .comparison
        .take()
        .unwrap();
    replacement.files.insert(0, comparison().files.remove(0));
    assert!(state.apply_result(10, Ok(Outcome::CheckoutRefresh(Some(replacement)))));
    assert_eq!(state.comparison_id, Some(10));
    assert_eq!(state.file, 1);
    assert_eq!(state.focus, Focus::After);
    assert!(state.word_wrap && !state.files_visible);
    assert_eq!(state.split_axis, crate::panes::SplitAxis::Horizontal);
    assert_eq!(state.view_mode, ViewMode::Unified);
    assert_eq!(state.comparison_mode, ComparisonMode::Snapshots);
    assert!(state.reviewed_files.is_empty());
    let files = state.files.as_ref().unwrap();
    assert_eq!(files.query, "file");
    assert_eq!(files.view, FileView::Tree);
    assert!(files.searching);
    assert_eq!(
        files.entries().nth(files.selected).unwrap().path,
        Path::new("file")
    );
    assert!(!state.apply_result(7, Ok(Outcome::CheckoutRefresh(None))));
    assert_eq!(state.comparison_id, Some(10));
    assert_eq!(state.file, 1);
    state.after.as_mut().unwrap().target = RevisionTarget::Commit("historical".into());
    state.queue_checkout_refresh(false);
    assert!(state.request_queued());
    assert!(matches!(
        state.take_request(),
        Some(Operation::RefreshCheckout {
            follow_working: false,
            ..
        })
    ));
    assert!(!state.apply_result(11, Ok(Outcome::CheckoutRefresh(None))));
    state.reviewed_files.insert(1);
    state.queue_checkout_refresh(false);
    state.take_request();
    let mut demoted = live_state(vec!["old".into()], vec!["ahead".into()], false)
        .comparison
        .take()
        .unwrap();
    demoted.files.insert(0, comparison().files.remove(0));
    demoted.editable_paths.clear();
    assert!(state.apply_result(12, Ok(Outcome::CheckoutRefresh(Some(demoted)))));
    assert_eq!(state.reviewed_files, BTreeSet::from([1]));
    assert!(!state.live_after_available());
    state
        .comparison
        .as_mut()
        .unwrap()
        .editable_paths
        .insert("file".into());
    state.refresh_after(&["dirty".into()], 1);
    assert_eq!(state.comparison.as_ref().unwrap().files[1].after, ["dirty"]);
    state.queue_checkout_refresh(false);
    state.take_request();
    assert!(state.apply_result(13, Err("checkout unavailable".into())));
    assert!(!state.live_after_available());
    assert_eq!(state.comparison_id, Some(12));
    assert_eq!(state.comparison.as_ref().unwrap().files[1].after, ["ahead"]);
    state.after.as_mut().unwrap().target = RevisionTarget::Working;
    state.queue_checkout_refresh(false);
    assert!(!state.request_queued());
    state.load_file(0);
    state.queue_checkout_refresh(true);
    assert!(matches!(
        state.pending,
        Some(Operation::LoadFile { file_index: 0, .. })
    ));
}

#[test]
fn reviewed_files_use_highlighted_catalog_indices_not_sorted_or_filtered_rows() {
    let mut state = DiffState::new();
    let mut changes = comparison();
    changes.files[0].path = "nested/z.txt".into();
    changes.files[1].path = "nested/a.txt".into();
    state.request_kind = Some(RequestKind::Comparison);
    state.apply_result(1, Ok(Outcome::Comparison(changes)));
    for view in [FileView::List, FileView::Tree] {
        let files = state.files.as_mut().unwrap();
        files.set_view(view);
        files.clear_filter();
        files.start_search();
        for ch in "nested/a".chars() {
            files.handle_filter_input(&Input::Char(ch));
        }
        files.reveal_path(Path::new("nested/a.txt"));
        assert_eq!(state.file, 0);
        assert_eq!(state.toggle_reviewed(), Ok(true));
        assert_eq!(state.reviewed_files, BTreeSet::from([1]));
        assert_eq!(state.toggle_reviewed(), Ok(false));
        assert!(state.reviewed_files.is_empty());
    }
    let files = state.files.as_mut().unwrap();
    files.clear_filter();
    files.finish_search();
    let selected = files.entries().position(|entry| entry.is_dir).unwrap();
    files.selected = selected;
    assert_eq!(
        state.toggle_reviewed(),
        Err("Select a changed file, not a directory")
    );
    assert!(state.reviewed_files.is_empty());
    let files = state.files.as_mut().unwrap();
    files.start_search();
    for ch in "missing".chars() {
        files.handle_filter_input(&Input::Char(ch));
    }
    assert_eq!(state.toggle_reviewed(), Err("No changed file is selected"));
    state.files = Some(FilePicker::from_paths(
        PathBuf::new(),
        [(0, PathBuf::from("ordinary.txt"))],
    ));
    assert_eq!(state.toggle_reviewed(), Err("No changed file is selected"));
    state.focus = Focus::Before;
    assert_eq!(state.toggle_reviewed(), Ok(true));
    assert_eq!(state.reviewed_files, BTreeSet::from([0]));
    assert!(state.select_file_index(2));
    state.focus = Focus::Before;
    assert_eq!(state.toggle_reviewed(), Ok(true));
    assert_eq!(state.reviewed_files, BTreeSet::from([0, 2]));
}

#[test]
fn reviewed_files_survive_lazy_details_and_views_but_reset_on_comparison() {
    let mut state = DiffState::new();
    assert_eq!(state.toggle_reviewed(), Err("No comparison is open"));
    let mut changes = comparison();
    changes.files[0].loaded = false;
    changes.files[0].before.clear();
    changes.files[0].after.clear();
    state.request_kind = Some(RequestKind::Comparison);
    state.apply_result(1, Ok(Outcome::Comparison(changes)));
    assert_eq!(state.toggle_reviewed(), Ok(true));
    assert_eq!(state.reviewed_files, BTreeSet::from([0]));
    let file = comparison().files.remove(0);
    state.apply_result(
        2,
        Ok(Outcome::File {
            comparison_id: 1,
            file_index: 0,
            file,
        }),
    );
    assert!(state.selected_file_loaded());
    state.set_view_mode(ViewMode::Unified);
    state.set_view_mode(ViewMode::Split);
    state.split_axis = crate::panes::SplitAxis::Horizontal;
    assert!(state.select_file_index(1));
    assert_eq!(state.reviewed_files, BTreeSet::from([0]));
    state.before = Some(revision(
        RevisionTarget::Commit("base".into()),
        "base",
        "",
        Category::Commits,
    ));
    state.after = Some(revision(
        RevisionTarget::Commit("head".into()),
        "head",
        "",
        Category::Commits,
    ));
    state.toggle_comparison_mode().unwrap();
    assert!(state.reviewed_files.is_empty());
    assert_eq!(state.toggle_reviewed(), Err("No comparison is open"));
    state.apply_result(3, Ok(Outcome::Comparison(comparison())));
    assert!(state.reviewed_files.is_empty());
    assert_eq!(state.toggle_reviewed(), Ok(true));
    state.request_kind = Some(RequestKind::Comparison);
    state.apply_result(4, Ok(Outcome::Comparison(comparison())));
    assert!(state.reviewed_files.is_empty());
}

#[test]
fn working_review_marks_clear_only_for_changed_bytes_or_eof() {
    for (after, eof, lines) in [
        (vec!["changed".into()], false, vec!["changed".into()]),
        (
            vec!["changed".into()],
            true,
            vec!["changed".into(), String::new()],
        ),
        (Vec::new(), false, vec![String::new()]),
    ] {
        let mut state = live_state(vec!["base".into()], after, eof);
        assert_eq!(state.toggle_reviewed(), Ok(true));
        state.refresh_after(&lines, 1);
        assert_eq!(state.reviewed_files, BTreeSet::from([0]));
        state.refresh_after(&lines, 2);
        assert_eq!(state.reviewed_files, BTreeSet::from([0]));
        state.refresh_after(&["edited".into()], 3);
        assert!(state.reviewed_files.is_empty());
        assert_eq!(state.toggle_reviewed(), Ok(true));
        state.refresh_after(&["edited".into(), String::new()], 4);
        assert!(state.reviewed_files.is_empty());
        assert_eq!(state.toggle_reviewed(), Ok(true));
        state.refresh_after(&["edited".into()], 5);
        assert!(state.reviewed_files.is_empty());
    }
    let mut state = live_state(vec!["base".into()], vec!["changed".into()], false);
    state.comparison.as_mut().unwrap().files[0].loaded = false;
    assert_eq!(state.toggle_reviewed(), Ok(true));
    state.refresh_after(&["edited".into()], 1);
    assert_eq!(state.reviewed_files, BTreeSet::from([0]));
}

#[test]
fn unified_groups_changed_runs_and_roundtrips_side_specific_source_rows() {
    let mut state = live_state(
        ["head", "old one", "old two", "tail"]
            .map(str::to_owned)
            .to_vec(),
        ["head", "new one", "new two", "extra", "tail"]
            .map(str::to_owned)
            .to_vec(),
        false,
    );
    assert_eq!(state.view_mode, ViewMode::Split);
    assert_eq!(state.split_axis, crate::panes::SplitAxis::Vertical);
    state.top = state.after_display_row(2).unwrap();
    let excerpts = state.excerpt_ranges.clone();
    state.set_view_mode(ViewMode::Unified);
    let rows: Vec<_> = (0..state.display_rows.len())
        .map(|display| {
            (
                state.display_focus(display),
                state.display_source_row(Focus::Before, display),
                state.display_source_row(Focus::After, display),
            )
        })
        .collect();
    assert_eq!(
        rows,
        [
            (None, Some(0), Some(0)),
            (Some(Focus::Before), Some(1), None),
            (Some(Focus::Before), Some(2), None),
            (Some(Focus::After), None, Some(1)),
            (Some(Focus::After), None, Some(2)),
            (Some(Focus::After), None, Some(3)),
            (None, Some(3), Some(4)),
        ]
    );
    assert_eq!(state.top, state.after_display_row(2).unwrap());
    assert_eq!(
        state.corresponding_row(Focus::Before, Focus::After, 2),
        Some(2)
    );
    assert!(state.after_editable());
    for focus in [Focus::Before, Focus::After] {
        for source in state.source_rows(focus) {
            let display = state.source_display_row(focus, source).unwrap();
            assert_eq!(state.display_source_row(focus, display), Some(source));
        }
    }
    state.set_view_mode(ViewMode::Split);
    assert_eq!(state.excerpt_ranges, excerpts);
    assert_eq!(state.focus, Focus::After);
    assert_eq!(state.top, state.after_display_row(2).unwrap());
    assert_eq!(state.display_rows.len(), 5);
}

#[test]
fn unified_live_reflow_preserves_removed_top_and_expanded_source_excerpts() {
    let base: Vec<_> = (0..40).map(|row| format!("line {row}")).collect();
    let mut lines = base.clone();
    lines[20] = "new line".into();
    let mut state = live_state(base, lines.clone(), false);
    state.set_context_options(1, 3);
    state.refresh_after(&lines, 1);
    state.set_view_mode(ViewMode::Unified);
    state.top = state.source_display_row(Focus::Before, 20).unwrap();
    state.expand_source_excerpt(Focus::After, false, 20);
    assert_eq!(state.display_source_row(Focus::Before, state.top), Some(20));
    assert!(state.source_display_row(Focus::After, 16).is_some());
    lines.insert(0, "inserted".into());
    state.refresh_after(&lines, 2);
    assert_eq!(state.display_focus(state.top), Some(Focus::Before));
    assert_eq!(state.display_source_row(Focus::Before, state.top), Some(20));
    assert!(state.source_display_row(Focus::After, 17).is_some());
    state.reveal_source_row(Focus::After, 35);
    let visible: Vec<_> = state.source_rows(Focus::After).collect();
    state.set_view_mode(ViewMode::Split);
    state.set_view_mode(ViewMode::Unified);
    assert_eq!(state.source_rows(Focus::After).collect::<Vec<_>>(), visible);
    assert_eq!(state.display_source_row(Focus::After, state.top), Some(35));
}

#[test]
fn character_ranges_follow_insertions_deletions_unicode_and_live_edits() {
    for (before, after, expected) in [
        ("ab", "a界b", vec![[1..1, 1..2]]),
        ("a界b", "ab", vec![[1..2, 1..1]]),
        ("xe\u{301}👩‍🚀z", "xe\u{300}👩‍🔬z", vec![[1..3, 1..3]]),
    ] {
        let state = live_state(vec![before.into()], vec![after.into()], false);
        assert_eq!(state.rows[0].changes, expected);
    }
    let mut state = live_state(vec!["abc".into()], vec!["aXbc".into()], false);
    state.refresh_after(&["aXYbc".into()], 1);
    assert_eq!(state.rows[0].changes, vec![[1..1, 1..3]]);
    state.refresh_after(&["abYZc".into()], 2);
    assert_eq!(state.rows[0].changes, vec![[2..2, 2..4]]);
    state.refresh_after(&["abc".into()], 3);
    assert_eq!(state.rows[0].kind, RowKind::Equal);
    assert!(state.rows[0].changes.is_empty());
}

#[test]
fn character_highlights_merge_incidental_matches_but_preserve_meaningful_gaps() {
    let mut cases = vec![
        ("a..c".into(), "b..d".into(), vec![[0..4, 0..4]]),
        ("base".into(), "edited".into(), vec![[0..4, 0..6]]),
        (
            "a...c".into(),
            "b...d".into(),
            vec![[0..1, 0..1], [4..5, 4..5]],
        ),
        (
            "a界e\u{301}c".into(),
            "b界e\u{301}d".into(),
            vec![[0..4, 0..4]],
        ),
    ];
    for (size, gap, merge) in [
        (60, " = ".to_owned(), false),
        (70, " = ".to_owned(), true),
        (70, "x".repeat(20), true),
        (70, "unchanged_expression".to_owned(), true),
        (70, "unchanged_expression_".to_owned(), false),
        (70, " ".repeat(500), true),
        (70, " ".repeat(501), false),
    ] {
        let end = 2 * size + gap.len();
        let second = size + gap.len();
        cases.push((
            format!("{}{}{}", "a".repeat(size), gap, "c".repeat(size)),
            format!("{}{}{}", "b".repeat(size), gap, "d".repeat(size)),
            if merge {
                vec![[0..end, 0..end]]
            } else {
                vec![[0..size, 0..size], [second..end, second..end]]
            },
        ));
    }
    cases.push((
        format!("aaa = {} = {}", "c".repeat(70), "e".repeat(70)),
        format!("bbb = {} = {}", "d".repeat(70), "f".repeat(70)),
        vec![[0..149, 0..149]],
    ));
    for (before, after, expected) in cases {
        let mut state = live_state(vec![before], vec![after.clone()], false);
        assert_eq!(state.rows[0].changes, expected, "{after:?}");
        state.refresh_after(&[format!("{after}!")], 1);
        state.refresh_after(std::slice::from_ref(&after), 2);
        assert_eq!(state.rows[0].changes, expected, "live edit: {after:?}");
    }
}

#[test]
fn reverting_loaded_file_keeps_unloaded_changes_selectable() {
    let mut state = live_state(vec!["base".into()], vec!["changed".into()], false);
    state.comparison_id = Some(17);
    state.pending = None;
    state.comparison.as_mut().unwrap().files.push(ChangedFile {
        path: "unloaded.txt".into(),
        old_path: None,
        status: FileStatus::Modified,
        loaded: false,
        before: vec![],
        after: vec![],
        before_eof: false,
        after_eof: false,
        hunks: vec![],
        notice: None,
    });
    state.refresh_after(&["base".into()], 1);
    assert_eq!(
        state
            .files
            .as_ref()
            .unwrap()
            .entries()
            .map(|entry| entry.path)
            .collect::<Vec<_>>(),
        [Path::new("unloaded.txt")],
    );
    assert!(state.select_file(Path::new("unloaded.txt")));
    assert!(matches!(
        state.take_request(),
        Some(Operation::LoadFile {
            comparison_id: 17,
            file_index: 1
        })
    ));
}

#[test]
fn live_width_cache_scans_only_changed_lines_and_shrinks_after_deletion() {
    let base = vec!["original".into(), "medium".into(), "short".into()];
    let mut lines = vec!["界\tz".into(), "medium".into(), "short".into()];
    let mut state = live_state(base, lines.clone(), false);
    state.refresh_after(&lines, 1);
    assert_eq!(state.after_widths, [5, 6, 5]);
    lines[0] = "界界\t🙂".into();
    WIDTH_SCANS.set(0);
    state.refresh_after(&lines, 2);
    assert_eq!(WIDTH_SCANS.get(), 1);
    assert_eq!(state.max_after, 10);
    state.left_after = 9;
    lines[0] = "界".into();
    WIDTH_SCANS.set(0);
    state.refresh_after(&lines, 3);
    assert_eq!(WIDTH_SCANS.get(), 1);
    assert_eq!(state.max_after, 6);
    assert_eq!(state.left_after, 6);
    lines.remove(1);
    WIDTH_SCANS.set(0);
    state.refresh_after(&lines, 4);
    assert_eq!(WIDTH_SCANS.get(), 0);
    assert_eq!(state.after_widths, [2, 5]);
    assert_eq!(state.max_after, 5);
    lines.insert(1, "巨大\t🙂".into());
    WIDTH_SCANS.set(0);
    state.refresh_after(&lines, 5);
    assert_eq!(WIDTH_SCANS.get(), 1);
    assert_eq!(state.after_widths, [2, 10, 5]);
    lines = vec!["".into()];
    state.refresh_after(&lines, 6);
    assert_eq!(state.after_widths, [0]);
    assert_eq!(state.max_after, 0);
    assert_eq!(state.left_after, 0);
}

#[test]
fn stable_line_edits_keep_fresh_hunks_expansion_and_scroll_anchor_until_revert() {
    let base = (0..100)
        .map(|row| format!("line {row}"))
        .collect::<Vec<_>>();
    let mut lines = base.clone();
    lines[30] = "first change".into();
    let mut state = live_state(base.clone(), lines.clone(), true);
    state.set_context_options(2, 5);
    lines.push(String::new());
    state.refresh_after(&lines, 1);
    state.top = state.after_display_row(30).unwrap();
    state.handle(Input::Char('['));
    let display = state.display_rows.clone();
    let excerpts = state.excerpt_ranges.clone();
    let top = state.top;
    lines[30].push('!');
    let file = &state.comparison.as_ref().unwrap().files[0];
    assert!(stable_after_edit(
        file,
        &lines,
        changed_line_range(&file.after, &lines)
    ));
    WIDTH_SCANS.set(0);
    state.refresh_after(&lines, 2);
    assert_eq!(WIDTH_SCANS.get(), 1);
    assert_eq!(state.display_rows, display);
    assert_eq!(state.excerpt_ranges, excerpts);
    assert_eq!(state.top, top);
    let file = &state.comparison.as_ref().unwrap().files[0];
    let hunk_ranges = |hunks: &[Hunk]| {
        hunks
            .iter()
            .map(|hunk| {
                (
                    hunk.before_start,
                    hunk.before_len,
                    hunk.after_start,
                    hunk.after_len,
                )
            })
            .collect::<Vec<_>>()
    };
    assert_eq!(
        hunk_ranges(&file.hunks),
        hunk_ranges(&line_hunks(&base, true, live_content(&lines, true), true))
    );
    lines[30].clone_from(&base[30]);
    assert!(!stable_after_edit(
        file,
        &lines,
        changed_line_range(&file.after, &lines)
    ));
    state.refresh_after(&lines, 3);
    assert!(state.comparison.as_ref().unwrap().files[0].hunks.is_empty());
    assert!(state.rows.iter().all(|row| row.kind == RowKind::Equal));
    assert!(state.after_display_row(23).is_some());
    assert_eq!(state.top, state.after_display_row(30).unwrap());
    assert_eq!(state.files.as_ref().unwrap().entries().len(), 0);
    lines[50] = "changed again".into();
    state.refresh_after(&lines, 4);
    assert_eq!(state.files.as_ref().unwrap().entries().len(), 1);
    assert!(state.after_display_row(23).is_some());
    assert!(state.after_display_row(50).is_some());
}

#[test]
fn live_reflow_keeps_separate_hunks_and_expanded_context_after_revert() {
    let base = (0..100)
        .map(|row| format!("line {row}"))
        .collect::<Vec<_>>();
    let mut changed = base.clone();
    changed[30] = "first change".into();
    changed[70] = "second change".into();
    let mut state = live_state(base.clone(), changed.clone(), true);
    state.set_context_options(2, 5);
    changed.push(String::new());
    state.refresh_after(&changed, 1);
    assert_eq!(state.comparison.as_ref().unwrap().files[0].hunks.len(), 2);
    assert!(
        state
            .rows
            .last()
            .is_some_and(|row| row.after == Some(100) && row.kind == RowKind::Equal)
    );
    state.top = state.after_display_row(30).unwrap();
    state.handle(Input::Char('['));
    assert!(state.after_display_row(23).is_some());
    changed.insert(10, "inserted outside excerpts".into());
    state.refresh_after(&changed, 2);
    assert!(state.after_display_row(24).is_some());
    assert_eq!(state.comparison.as_ref().unwrap().files[0].hunks.len(), 3);
    assert!(
        state
            .display_rows
            .iter()
            .any(|row| matches!(row, DisplayRow::Fold { start, end } if *start < 60 && *end > 40))
    );
    let mut reverted = base;
    reverted.push(String::new());
    state.refresh_after(&reverted, 3);
    assert!(state.comparison.as_ref().unwrap().files[0].hunks.is_empty());
    assert!(state.rows.iter().all(|row| row.kind == RowKind::Equal));
    assert!(state.after_display_row(23).is_some());
    assert!(state.after_display_row(90).is_none());
    assert_eq!(state.files.as_ref().unwrap().entries().len(), 0);
    assert_eq!(state.file, 0);
    reverted[50] = "changed again".into();
    state.refresh_after(&reverted, 4);
    assert_eq!(state.files.as_ref().unwrap().entries().len(), 1);
    assert!(state.after_display_row(50).is_some());
}

#[test]
fn live_empty_and_eof_rows_match_buffer_without_false_eof_highlights() {
    let mut state = live_state(vec!["same".into()], vec!["changed".into()], true);
    state.refresh_after(&["same".into(), "".into()], 1);
    assert!(state.comparison.as_ref().unwrap().files[0].hunks.is_empty());
    assert_eq!(state.rows.len(), 2);
    assert!(state.rows.iter().all(|row| row.kind == RowKind::Equal));
    assert!(state.after_display_row(0).is_some());
    assert!(state.after_display_row(1).is_none());
    state.refresh_after(&["same".into()], 2);
    assert_eq!(state.rows[0].kind, RowKind::Changed);
    assert!(
        state.comparison.as_ref().unwrap().files[0]
            .notice
            .as_ref()
            .unwrap()
            .contains("After missing")
    );
    state.refresh_after(&["".into()], 3);
    assert!(state.after_display_row(0).is_some());
    assert_eq!(state.comparison.as_ref().unwrap().files[0].after, [""]);
    let mut empty = live_state(vec![], vec!["text".into()], false);
    empty.refresh_after(&["".into()], 1);
    assert!(empty.comparison.as_ref().unwrap().files[0].hunks.is_empty());
    assert_eq!(empty.rows.len(), 1);
    assert_eq!(empty.rows[0].kind, RowKind::Equal);
    assert_eq!(empty.after_display_row(0), Some(0));
    empty.after.as_mut().unwrap().target = RevisionTarget::Commit("historic".into());
    empty.comparison.as_mut().unwrap().editable_paths.clear();
    empty.refresh_after(&["must not apply".into()], 2);
    assert_eq!(empty.comparison.as_ref().unwrap().files[0].after, [""]);
    empty.handle(Input::Escape);
    assert_eq!(empty.phase, Phase::View);
}

#[test]
fn lazy_selection_waits_for_details_rejects_stale_files_and_reuses_loaded_cache() {
    let mut state = DiffState::new();
    state.pending = None;
    state.request_kind = Some(RequestKind::Comparison);
    let mut catalog = comparison();
    catalog.files.truncate(2);
    let details: Vec<_> = catalog.files.drain(..).collect();
    for detail in &details {
        catalog.files.push(ChangedFile {
            path: detail.path.clone(),
            old_path: detail.old_path.clone(),
            status: detail.status,
            loaded: false,
            before: vec![],
            after: vec![],
            before_eof: false,
            after_eof: false,
            hunks: vec![],
            notice: None,
        });
    }
    state.apply_result(41, Ok(Outcome::Comparison(catalog)));
    assert!(!state.selected_file_loaded());
    assert!(state.rows.is_empty() && state.display_rows.is_empty());
    assert_eq!(state.pane_layout(), PaneLayout::Empty);
    assert!(!state.after_editable());
    assert!(matches!(
        state.take_request(),
        Some(Operation::LoadFile {
            comparison_id: 41,
            file_index: 0,
        })
    ));
    assert!(state.select_file(Path::new("added.txt")));
    assert!(matches!(
        state.take_request(),
        Some(Operation::LoadFile {
            comparison_id: 41,
            file_index: 1,
        })
    ));
    let mut details = details.into_iter();
    let first = details.next().unwrap();
    let second = details.next().unwrap();
    state.apply_result(
        42,
        Ok(Outcome::File {
            comparison_id: 40,
            file_index: 1,
            file: first,
        }),
    );
    assert!(state.loading && !state.selected_file_loaded());
    state.apply_result(
        43,
        Ok(Outcome::File {
            comparison_id: 41,
            file_index: 1,
            file: second,
        }),
    );
    assert!(state.selected_file_loaded());
    assert_eq!(state.pane_layout(), PaneLayout::After);
    assert!(!state.rows.is_empty());
    assert!(state.select_file(Path::new("renamed.txt")));
    assert!(state.loading);
    assert!(state.select_file(Path::new("added.txt")));
    assert!(!state.loading && state.selected_file_loaded());
    assert!(state.take_request().is_none());
    state.apply_result(44, Err("cancelled old load".into()));
    assert!(state.error.is_none() && state.selected_file_loaded());
}

#[test]
fn failed_lazy_file_load_can_be_retried_without_reopening_comparison() {
    let mut state = DiffState::new();
    state.pending = None;
    state.request_kind = Some(RequestKind::Comparison);
    let mut catalog = comparison();
    catalog.files.truncate(1);
    catalog.files[0].loaded = false;
    state.apply_result(7, Ok(Outcome::Comparison(catalog)));
    state.take_request();
    state.apply_result(8, Err("cannot read blob".into()));
    assert_eq!(state.error.as_deref(), Some("cannot read blob"));
    assert!(!state.selected_file_loaded());
    assert!(state.select_file(Path::new("renamed.txt")));
    assert!(state.loading && state.error.is_none());
    assert!(matches!(
        state.take_request(),
        Some(Operation::LoadFile {
            comparison_id: 7,
            file_index: 0,
        })
    ));
}

#[test]
fn mode_action_keeps_filter_input_and_rejects_superseded_comparisons() {
    let mut editor = editor();
    open(&mut editor);
    editor
        .bind("normal", "m", Some("core.diff.mode.toggle".into()))
        .unwrap();
    text(&mut editor, "m");
    assert_eq!(editor.diff().unwrap().query, "m");
    assert_eq!(
        editor.diff().unwrap().comparison_mode,
        ComparisonMode::BranchChanges
    );
    editor.handle(Input::Ctrl('u'));
    editor.handle(Input::Down);
    editor.handle(Input::Enter);
    editor.handle(Input::Down);
    editor.handle(Input::Enter);
    let (old, _) = editor.take_diff_request().unwrap();
    editor.execute("diff.mode.toggle");
    assert!(!editor.apply_diff_result(old, Err("superseded".into())));
    let (current, operation) = editor.take_diff_request().unwrap();
    assert!(matches!(
        operation,
        Operation::Compare {
            mode: ComparisonMode::Snapshots,
            ..
        }
    ));
    assert!(editor.apply_diff_result(current, Err("retryable".into())));
    assert_eq!(editor.diff().unwrap().phase, Phase::After);
    assert_eq!(editor.diff().unwrap().error.as_deref(), Some("retryable"));
    editor.execute("diff.mode.toggle");
    let (_, operation) = editor.take_diff_request().unwrap();
    assert!(matches!(
        operation,
        Operation::Compare {
            mode: ComparisonMode::BranchChanges,
            ..
        }
    ));
    assert!(editor.diff().unwrap().error.is_none());
}

#[test]
fn review_anchors_match_frozen_context_and_exact_live_eof_without_allocating() {
    use crate::review::{Anchor, Side};
    let mut state = live_state(vec!["old".into()], vec!["new".into()], true);
    let anchor = Anchor {
        revision: "working:snapshot".into(),
        path: "file".into(),
        side: Side::After,
        start: crate::plugin::TextPosition { row: 0, column: 0 },
        end: crate::plugin::TextPosition { row: 1, column: 0 },
        content: "new\n".into(),
    };
    assert!(state.review_anchor_current(&anchor));
    state.live_files.insert(0);
    assert!(!state.review_anchor_current(&anchor));
    state.comparison.as_mut().unwrap().files[0]
        .after
        .push(String::new());
    assert!(state.review_anchor_current(&anchor));
    state.comparison.as_mut().unwrap().files[0].after[0] = "changed".into();
    assert!(!state.review_anchor_current(&anchor));
    state.comparison.as_mut().unwrap().files[0].old_path = Some("original".into());
    let before = Anchor {
        revision: "base".into(),
        path: "original".into(),
        side: Side::Before,
        content: "old\n".into(),
        ..anchor
    };
    assert!(state.review_anchor_current(&before));
    state.comparison.as_mut().unwrap().files[0].loaded = false;
    assert!(!state.review_anchor_current(&before));
    state.comparison.as_mut().unwrap().files[0].loaded = true;
    state.comparison.as_mut().unwrap().revisions[0] = "other".into();
    assert!(!state.review_anchor_current(&before));
}