trail/input/

keymap.rs

//! Default and user-configured key bindings.
//!
//! Resolves `[keymap]` TOML tables to `Action` values for each mode. Arrow
//! keys and Enter remain built-in aliases for ergonomic terminal navigation.

use crossterm::event::{KeyCode, KeyEvent, KeyModifiers};

use crate::actions::transfer::TransferKind;
use crate::actions::Action;
use crate::app::sort::SortBy;
use crate::app::state::AppState;
use crate::config::KeymapConfig;
use crate::input::InputCtx;

/// Translates a `KeyEvent` in Navigation Mode into an `Action`.
///
/// Configured bindings are resolved first from `state.config.keymap`. Built-in
/// non-text fallbacks such as arrows, Enter, and Backspace are then checked.
/// Multi-key sequences are represented by compact strings such as `gg`, `ya`,
/// and `dd`.
pub fn navigation(key: KeyEvent, _ctx: &mut InputCtx, state: &AppState) -> Option<Action> {
    if state.pending_delete {
        return match key.code {
            KeyCode::Enter | KeyCode::Char('y') => Some(Action::ConfirmDelete),
            KeyCode::Esc | KeyCode::Char('n') => Some(Action::CancelDelete),
            _ => None,
        };
    }

    if let Some(pending) = state.pending_nav_key {
        if let Some(sequence) = append_to_sequence(pending, key) {
            return nav_action_for_sequence(&state.config.keymap, &sequence);
        }
        return None;
    }

    if let Some(action) = configured_nav_action(key, &state.config.keymap) {
        return Some(action);
    }

    if let Some(prefix) = configured_nav_prefix(key, &state.config.keymap) {
        return Some(Action::SetPendingNavKey(prefix));
    }

    match key.code {
        // Shift+arrow scrolls the preview — checked before the bare arrows,
        // which match on the key code alone and would otherwise swallow it and
        // move the selection instead.
        KeyCode::Down if key.modifiers.contains(KeyModifiers::SHIFT) => {
            Some(Action::PreviewScrollDown)
        }
        KeyCode::Up if key.modifiers.contains(KeyModifiers::SHIFT) => Some(Action::PreviewScrollUp),
        KeyCode::Down => Some(Action::MoveDown),
        KeyCode::Up => Some(Action::MoveUp),
        KeyCode::Enter | KeyCode::Right => Some(Action::EnterOrOpen),
        KeyCode::Backspace | KeyCode::Left => Some(Action::GoParent),
        // Ctrl+C cancels Trail without writing --cwd-file.
        KeyCode::Char('c') if is_ctrl_chord(key.modifiers) => Some(Action::Cancel),
        // Phase 8: tab management built-in fallbacks.
        // These fire when not overridden by a configured keymap binding.
        KeyCode::Char('t') if is_ctrl_chord(key.modifiers) => Some(Action::NewTab),
        KeyCode::Char('w') if is_ctrl_chord(key.modifiers) => Some(Action::CloseTab),
        KeyCode::Tab if key.modifiers.contains(KeyModifiers::SHIFT) => Some(Action::SwitchTabPrev),
        KeyCode::Tab => Some(Action::SwitchTabNext),
        KeyCode::Esc => None,
        _ => None,
    }
}

/// Translates a `KeyEvent` in Visual Mode into an `Action`.
///
/// Visual mode shares Navigation Mode's bindings — `j`, `k`, `G`, `gg` and the
/// arrows move exactly as they do there, which is what extends the range — and
/// reinterprets the few that end it:
///
/// - `Space` and `v` add the range to the marks;
/// - `h`/`l` (and the other ways of leaving the directory) add it and then go;
/// - `Esc` abandons it, leaving the marks as they were;
/// - `dd` deletes it, after one confirmation.
///
/// Everything else is ignored: a yank or a paste in the middle of selecting is
/// more likely a slip than a request.
pub fn visual(key: KeyEvent, ctx: &mut InputCtx, state: &AppState) -> Option<Action> {
    let action = navigation(key, ctx, state)?;
    match action {
        Action::MoveDown
        | Action::MoveUp
        | Action::JumpTop
        | Action::JumpBottom
        | Action::SetPendingNavKey(_)
        | Action::BeginDelete
        | Action::ConfirmDelete
        | Action::CancelDelete
        | Action::Cancel
        | Action::PreviewScrollDown
        | Action::PreviewScrollUp
        | Action::PreviewPageDown
        | Action::PreviewPageUp
        | Action::PreviewScrollTop
        | Action::PreviewScrollBottom => Some(action),
        Action::ToggleMark | Action::EnterVisual => Some(Action::CommitVisual(None)),
        Action::GoParent
        | Action::EnterOrOpen
        | Action::HistoryBack
        | Action::HistoryForward
        | Action::ReturnFromJump => Some(Action::CommitVisual(Some(Box::new(action)))),
        Action::ClearMarks => Some(Action::ExitMode),
        _ => None,
    }
}

/// Translates a `KeyEvent` in Search Mode into an `Action`.
///
/// Search Mode is a typing mode, so an unmodified printable character is
/// **always** appended to the query — before the configured keymap is even
/// consulted. Binding a bare character to a movement action here would make
/// that character impossible to search for, which is exactly what the shipped
/// defaults used to do with `j` and `k`: the list moved and the letter never
/// reached the query.
///
/// Everything that is not text therefore drives the mode: arrows and
/// `Ctrl-n`/`Ctrl-p` move, Enter confirms, Esc leaves, Backspace deletes.
/// Those are what `[keymap.search]` may rebind, and
/// `TrailConfig::validate` rejects a single-character binding so the
/// shadowing cannot be reintroduced through config.
pub fn search(key: KeyEvent, keymap: &KeymapConfig) -> Option<Action> {
    if let KeyCode::Char(ch) = key.code {
        // Capitals (Shift) and AltGr characters (Ctrl+Alt on Windows) are text too.
        if super::is_text_modifiers(key.modifiers) {
            return Some(Action::SearchAppendChar(ch));
        }
    }

    if let Some(action) = configured_search_action(key, keymap) {
        return Some(action);
    }

    match key.code {
        KeyCode::Esc => Some(Action::ExitMode),
        KeyCode::Enter | KeyCode::Right => Some(Action::SearchConfirm),
        KeyCode::Down => Some(Action::SearchMoveDown),
        KeyCode::Up => Some(Action::SearchMoveUp),
        KeyCode::Backspace => Some(Action::SearchDeleteChar),
        // Readline-style chords, so the hands never have to leave the home row
        // now that j/k are text. Built-in aliases, like Ctrl-h for backspace.
        KeyCode::Char('n') if key.modifiers.contains(KeyModifiers::CONTROL) => {
            Some(Action::SearchMoveDown)
        }
        KeyCode::Char('p') if key.modifiers.contains(KeyModifiers::CONTROL) => {
            Some(Action::SearchMoveUp)
        }
        KeyCode::Char('h') if key.modifiers.contains(KeyModifiers::CONTROL) => {
            Some(Action::SearchDeleteChar)
        }
        _ => None,
    }
}

fn configured_nav_action(key: KeyEvent, keymap: &KeymapConfig) -> Option<Action> {
    let key_text = key_to_config_string(key)?;
    nav_action_for_sequence(keymap, &key_text)
}

fn configured_search_action(key: KeyEvent, keymap: &KeymapConfig) -> Option<Action> {
    let key_text = key_to_config_string(key)?;
    keymap.search.iter().find_map(|(name, binding)| {
        if binding == &key_text {
            search_action_from_name(name)
        } else {
            None
        }
    })
}

/// Returns `ch` when it is the first key of a configured multi-key sequence
/// such as `gg` or `ya`, so the dispatcher waits for the second key.
///
/// Named-key bindings are excluded before the prefix test. A binding like
/// `tab` or `ctrl-r` is one key, not the letters it is spelled with; without
/// the exclusion `t` and `c` became prefixes that nothing could complete, and
/// each silently swallowed the keystroke after it.
fn configured_nav_prefix(key: KeyEvent, keymap: &KeymapConfig) -> Option<char> {
    let KeyCode::Char(ch) = key.code else {
        return None;
    };
    if is_ctrl_chord(key.modifiers) {
        return None;
    }
    keymap
        .navigation
        .values()
        .filter(|binding| !is_named_key(binding))
        .any(|binding| binding.len() > ch.len_utf8() && binding.starts_with(ch))
        .then_some(ch)
}

/// Whether a character key with `modifiers` is a Ctrl chord rather than a
/// typed character.
///
/// Ctrl **and** Alt together is how Windows reports AltGr, which Spanish,
/// Latin American, German and many other layouts need for `@`, `\`, `|`,
/// `~`, `{` and `[`. Read as Ctrl, AltGr+Q on es-MX arrived as `ctrl-@` and
/// matched nothing, so a binding of `@` could never be pressed there — the
/// same trap §2.18 fixed for Command and Search Mode.
fn is_ctrl_chord(modifiers: KeyModifiers) -> bool {
    modifiers.contains(KeyModifiers::CONTROL) && !super::is_text_modifiers(modifiers)
}

/// Every key name [`key_to_config_string`] can produce without a modifier.
const NAMED_KEYS: &[&str] = &[
    "enter",
    "esc",
    "backspace",
    "tab",
    "left",
    "right",
    "up",
    "down",
    "home",
    "end",
    "space",
];

/// Whether `binding` names a single key — `tab`, `ctrl-r`, `shift-end` — as
/// opposed to a sequence of typed characters.
///
/// Matches exactly the spellings [`key_to_config_string`] produces: a bare key
/// name, or one prefixed with `ctrl-` or `shift-`.
fn is_named_key(binding: &str) -> bool {
    let base = binding
        .strip_prefix("ctrl-")
        .or_else(|| binding.strip_prefix("shift-"))
        .unwrap_or(binding);
    binding != base || NAMED_KEYS.contains(&base)
}

fn nav_action_for_sequence(keymap: &KeymapConfig, sequence: &str) -> Option<Action> {
    keymap.navigation.iter().find_map(|(name, binding)| {
        if binding == sequence {
            nav_action_from_name(name)
        } else {
            None
        }
    })
}

fn nav_action_from_name(name: &str) -> Option<Action> {
    match name {
        "move_down" => Some(Action::MoveDown),
        "move_up" => Some(Action::MoveUp),
        "jump_top" => Some(Action::JumpTop),
        "jump_bottom" => Some(Action::JumpBottom),
        "enter_or_open" => Some(Action::EnterOrOpen),
        "go_parent" => Some(Action::GoParent),
        "history_back" => Some(Action::HistoryBack),
        "history_forward" => Some(Action::HistoryForward),
        "return_from_jump" => Some(Action::ReturnFromJump),
        "refresh" => Some(Action::Refresh),
        "toggle_hidden" => Some(Action::ToggleHidden),
        // Listing order. `s` is never bound on its own: `configured_nav_prefix`
        // makes any first character of a longer binding a prefix, so these six
        // give it its meaning without any change to the sequence machinery.
        "sort_name" => Some(Action::SetSortBy(SortBy::Name)),
        "sort_size" => Some(Action::SetSortBy(SortBy::Size)),
        "sort_time" => Some(Action::SetSortBy(SortBy::Modified)),
        "sort_extension" => Some(Action::SetSortBy(SortBy::Extension)),
        "sort_reverse" => Some(Action::ToggleSortReverse),
        "sort_dirs_first" => Some(Action::ToggleDirsFirst),
        "toggle_details" => Some(Action::CycleEntryDetails),
        "copy_absolute_path" => Some(Action::CopyAbsPath),
        "copy_relative_path" => Some(Action::CopyRelPath),
        "copy_filename" => Some(Action::CopyFilename),
        "copy_content" => Some(Action::CopyContent),
        "delete" => Some(Action::BeginDelete),
        "toggle_mark" => Some(Action::ToggleMark),
        "clear_marks" => Some(Action::ClearMarks),
        "paste_copy" => Some(Action::PasteMarks(TransferKind::Copy)),
        "paste_move" => Some(Action::PasteMarks(TransferKind::Move)),
        "enter_visual" => Some(Action::EnterVisual),
        "repeat_command" => Some(Action::RepeatLastCommand),
        "enter_search" => Some(Action::EnterSearch),
        "enter_command" => Some(Action::EnterCommand),
        "quit" => Some(Action::Quit),
        "open_with_os" => Some(Action::OpenWithOs),
        // Phase 8: tab management.
        "new_tab" => Some(Action::NewTab),
        "close_tab" => Some(Action::CloseTab),
        "switch_tab_next" => Some(Action::SwitchTabNext),
        "switch_tab_prev" => Some(Action::SwitchTabPrev),
        // Preview pane scrolling.
        "preview_scroll_down" => Some(Action::PreviewScrollDown),
        "preview_scroll_up" => Some(Action::PreviewScrollUp),
        "preview_page_down" => Some(Action::PreviewPageDown),
        "preview_page_up" => Some(Action::PreviewPageUp),
        "preview_scroll_top" => Some(Action::PreviewScrollTop),
        "preview_scroll_bottom" => Some(Action::PreviewScrollBottom),
        _ => None,
    }
}

fn search_action_from_name(name: &str) -> Option<Action> {
    match name {
        "exit" => Some(Action::ExitMode),
        "confirm" => Some(Action::SearchConfirm),
        "move_down" => Some(Action::SearchMoveDown),
        "move_up" => Some(Action::SearchMoveUp),
        "delete_char" => Some(Action::SearchDeleteChar),
        _ => None,
    }
}

fn append_to_sequence(prefix: char, key: KeyEvent) -> Option<String> {
    let KeyCode::Char(ch) = key.code else {
        return None;
    };
    if is_ctrl_chord(key.modifiers) {
        return None;
    }
    Some(format!("{prefix}{ch}"))
}

/// Renders `key` in the form `[keymap]` bindings are written in, or `None` for
/// a key with no config spelling.
///
/// A character carries its own shift: crossterm delivers `Shift`+`j` as
/// `Char('J')`, which is why `jump_bottom = "G"` works and why a `shift-`
/// prefix is added only to *named* keys — `shift-down`, `shift-end`. Without
/// that prefix every shifted arrow would be indistinguishable from the bare
/// one, and `Shift`+`↓` could not scroll the preview while `↓` moves the
/// selection.
fn key_to_config_string(key: KeyEvent) -> Option<String> {
    let named = match key.code {
        KeyCode::Char(ch) if is_ctrl_chord(key.modifiers) => {
            return Some(format!("ctrl-{ch}").to_ascii_lowercase());
        }
        // A space is spelled out: a binding of " " would be invisible in the
        // config file, and easy to take for an empty string.
        KeyCode::Char(' ') => "space",
        KeyCode::Char(ch) => return Some(ch.to_string()),
        KeyCode::Enter => "enter",
        KeyCode::Esc => "esc",
        KeyCode::Backspace => "backspace",
        KeyCode::Tab => "tab",
        // Terminals split on how they report Shift+Tab: some send Tab with the
        // shift modifier, others a distinct BackTab with no modifier. Both must
        // reach the same binding.
        KeyCode::BackTab => return Some("shift-tab".to_owned()),
        KeyCode::Left => "left",
        KeyCode::Right => "right",
        KeyCode::Up => "up",
        KeyCode::Down => "down",
        KeyCode::Home => "home",
        KeyCode::End => "end",
        _ => return None,
    };

    if key.modifiers.contains(KeyModifiers::SHIFT) {
        Some(format!("shift-{named}"))
    } else {
        Some(named.to_owned())
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use crossterm::event::{KeyEventKind, KeyEventState};

    /// The bug this guards: `tab` made `t` a prefix and `ctrl-r` made `c` one,
    /// so each waited for a second key that could never complete a sequence
    /// and swallowed it.
    #[test]
    fn a_named_key_binding_does_not_make_its_first_letter_a_prefix() {
        let keymap = crate::config::load(None).unwrap().keymap;
        assert_eq!(
            configured_nav_prefix(key(KeyCode::Char('t')), &keymap),
            None
        );
        assert_eq!(
            configured_nav_prefix(key(KeyCode::Char('c')), &keymap),
            None
        );
    }

    #[test]
    fn real_sequences_still_make_prefixes() {
        let keymap = crate::config::load(None).unwrap().keymap;
        for ch in ['g', 'y', 'd', 's'] {
            assert_eq!(
                configured_nav_prefix(key(KeyCode::Char(ch)), &keymap),
                Some(ch),
                "`{ch}` starts a default sequence"
            );
        }
    }

    /// `is_named_key` has to recognise every spelling the key translator can
    /// produce, or a new named key would reintroduce the swallowed keystroke.
    #[test]
    fn every_translated_named_key_is_recognised() {
        let codes = [
            KeyCode::Enter,
            KeyCode::Esc,
            KeyCode::Backspace,
            KeyCode::Tab,
            KeyCode::BackTab,
            KeyCode::Left,
            KeyCode::Right,
            KeyCode::Up,
            KeyCode::Down,
            KeyCode::Home,
            KeyCode::End,
            KeyCode::Char(' '),
        ];
        for code in codes {
            for modifiers in [KeyModifiers::NONE, KeyModifiers::SHIFT] {
                let event = KeyEvent {
                    modifiers,
                    ..key(code)
                };
                let name = key_to_config_string(event).expect("named key translates");
                assert!(is_named_key(&name), "`{name}` is not recognised as named");
            }
        }
        assert!(is_named_key("ctrl-r"));
        assert!(!is_named_key("gg"));
        assert!(!is_named_key("t"));
    }

    fn key(code: KeyCode) -> KeyEvent {
        KeyEvent {
            code,
            modifiers: KeyModifiers::NONE,
            kind: KeyEventKind::Press,
            state: KeyEventState::NONE,
        }
    }

    #[test]
    fn parses_ctrl_key_binding() {
        let event = KeyEvent {
            code: KeyCode::Char('r'),
            modifiers: KeyModifiers::CONTROL,
            kind: KeyEventKind::Press,
            state: KeyEventState::NONE,
        };
        assert_eq!(key_to_config_string(event), Some("ctrl-r".to_owned()));
    }

    /// The bug this guards: `j` and `k` moved the selection instead of being
    /// typed, so neither letter could appear in a search query. A configured
    /// binding must not be able to reintroduce that.
    #[test]
    fn search_types_every_bare_character_even_when_bound() {
        let mut keymap = crate::config::load(None).unwrap().keymap;
        keymap.search.insert("move_down".to_owned(), "j".to_owned());
        keymap.search.insert("move_up".to_owned(), "k".to_owned());

        for ch in ['j', 'k', 'q', ':', '/', 'Z'] {
            assert_eq!(
                search(key(KeyCode::Char(ch)), &keymap),
                Some(Action::SearchAppendChar(ch)),
                "{ch} must reach the query"
            );
        }
    }

    #[test]
    fn search_moves_with_keys_that_are_not_text() {
        let keymap = crate::config::load(None).unwrap().keymap;
        let ctrl = |ch| KeyEvent {
            code: KeyCode::Char(ch),
            modifiers: KeyModifiers::CONTROL,
            kind: KeyEventKind::Press,
            state: KeyEventState::NONE,
        };

        assert_eq!(
            search(key(KeyCode::Down), &keymap),
            Some(Action::SearchMoveDown)
        );
        assert_eq!(
            search(key(KeyCode::Up), &keymap),
            Some(Action::SearchMoveUp)
        );
        assert_eq!(search(ctrl('n'), &keymap), Some(Action::SearchMoveDown));
        assert_eq!(search(ctrl('p'), &keymap), Some(Action::SearchMoveUp));
        assert_eq!(search(ctrl('h'), &keymap), Some(Action::SearchDeleteChar));
        assert_eq!(
            search(key(KeyCode::Enter), &keymap),
            Some(Action::SearchConfirm)
        );
        assert_eq!(search(key(KeyCode::Esc), &keymap), Some(Action::ExitMode));
    }

    #[test]
    fn shifted_characters_are_still_text() {
        let keymap = crate::config::load(None).unwrap().keymap;
        let shifted = KeyEvent {
            code: KeyCode::Char('K'),
            modifiers: KeyModifiers::SHIFT,
            kind: KeyEventKind::Press,
            state: KeyEventState::NONE,
        };
        assert_eq!(
            search(shifted, &keymap),
            Some(Action::SearchAppendChar('K'))
        );
    }

    /// Windows reports AltGr as Ctrl+Alt; on es-MX that is how `\` is typed.
    #[test]
    fn altgr_characters_are_text() {
        let keymap = crate::config::load(None).unwrap().keymap;
        let altgr = KeyEvent {
            code: KeyCode::Char('\\'),
            modifiers: KeyModifiers::CONTROL | KeyModifiers::ALT,
            kind: KeyEventKind::Press,
            state: KeyEventState::NONE,
        };
        assert_eq!(search(altgr, &keymap), Some(Action::SearchAppendChar('\\')));
    }

    /// A shifted character carries its own capital, so `J`/`K` reach the
    /// preview-scroll actions through the ordinary configured path — the same
    /// one that already serves `G`.
    #[test]
    fn preview_scroll_bindings_resolve_from_defaults() {
        let dir = tempfile::tempdir().unwrap();
        let state = AppState::new(dir.path().to_owned()).unwrap();
        let mut ctx = InputCtx::default();
        let ctrl = |ch| KeyEvent {
            code: KeyCode::Char(ch),
            modifiers: KeyModifiers::CONTROL,
            kind: KeyEventKind::Press,
            state: KeyEventState::NONE,
        };
        let shifted = |code| KeyEvent {
            code,
            modifiers: KeyModifiers::SHIFT,
            kind: KeyEventKind::Press,
            state: KeyEventState::NONE,
        };

        for (event, expected) in [
            (key(KeyCode::Char('J')), Action::PreviewScrollDown),
            (key(KeyCode::Char('K')), Action::PreviewScrollUp),
            (ctrl('f'), Action::PreviewPageDown),
            (ctrl('b'), Action::PreviewPageUp),
            (shifted(KeyCode::Home), Action::PreviewScrollTop),
            (shifted(KeyCode::End), Action::PreviewScrollBottom),
        ] {
            assert_eq!(
                navigation(event, &mut ctx, &state),
                Some(expected.clone()),
                "{event:?} must map to {expected:?}"
            );
        }
    }

    /// The bug this guards: the built-in arrow fallbacks match on the key code
    /// alone, so `Shift+↓` used to move the selection. It must scroll the
    /// preview while the bare arrow still moves, and `j`/`k` must be untouched.
    #[test]
    fn shift_arrows_scroll_the_preview_and_bare_arrows_still_move() {
        let dir = tempfile::tempdir().unwrap();
        let state = AppState::new(dir.path().to_owned()).unwrap();
        let mut ctx = InputCtx::default();
        let shifted = |code| KeyEvent {
            code,
            modifiers: KeyModifiers::SHIFT,
            kind: KeyEventKind::Press,
            state: KeyEventState::NONE,
        };

        assert_eq!(
            navigation(shifted(KeyCode::Down), &mut ctx, &state),
            Some(Action::PreviewScrollDown)
        );
        assert_eq!(
            navigation(shifted(KeyCode::Up), &mut ctx, &state),
            Some(Action::PreviewScrollUp)
        );
        assert_eq!(
            navigation(key(KeyCode::Down), &mut ctx, &state),
            Some(Action::MoveDown)
        );
        assert_eq!(
            navigation(key(KeyCode::Up), &mut ctx, &state),
            Some(Action::MoveUp)
        );
        assert_eq!(
            navigation(key(KeyCode::Char('j')), &mut ctx, &state),
            Some(Action::MoveDown)
        );
        assert_eq!(
            navigation(key(KeyCode::Char('k')), &mut ctx, &state),
            Some(Action::MoveUp)
        );
    }

    #[test]
    fn shift_is_spelled_out_for_named_keys_only() {
        let shifted = |code| KeyEvent {
            code,
            modifiers: KeyModifiers::SHIFT,
            kind: KeyEventKind::Press,
            state: KeyEventState::NONE,
        };

        assert_eq!(
            key_to_config_string(shifted(KeyCode::Down)),
            Some("shift-down".to_owned())
        );
        assert_eq!(
            key_to_config_string(shifted(KeyCode::End)),
            Some("shift-end".to_owned())
        );
        assert_eq!(
            key_to_config_string(key(KeyCode::Home)),
            Some("home".to_owned())
        );
        // A capital is already the shifted form of the character.
        assert_eq!(
            key_to_config_string(shifted(KeyCode::Char('J'))),
            Some("J".to_owned())
        );
        // Terminals that send BackTab instead of Shift+Tab reach the same binding.
        assert_eq!(
            key_to_config_string(key(KeyCode::BackTab)),
            Some("shift-tab".to_owned())
        );
        assert_eq!(
            key_to_config_string(shifted(KeyCode::Tab)),
            Some("shift-tab".to_owned())
        );
    }

    #[test]
    fn mark_and_paste_bindings_resolve_from_defaults() {
        let dir = tempfile::tempdir().unwrap();
        let mut state = AppState::new(dir.path().to_owned()).unwrap();
        let mut ctx = InputCtx::default();

        assert_eq!(
            navigation(key(KeyCode::Char(' ')), &mut ctx, &state),
            Some(Action::ToggleMark)
        );
        assert_eq!(
            navigation(key(KeyCode::Esc), &mut ctx, &state),
            Some(Action::ClearMarks)
        );
        assert_eq!(
            navigation(key(KeyCode::Char('p')), &mut ctx, &state),
            Some(Action::SetPendingNavKey('p'))
        );
        state.pending_nav_key = Some('p');
        assert_eq!(
            navigation(key(KeyCode::Char('p')), &mut ctx, &state),
            Some(Action::PasteMarks(TransferKind::Copy))
        );
        assert_eq!(
            navigation(key(KeyCode::Char('m')), &mut ctx, &state),
            Some(Action::PasteMarks(TransferKind::Move))
        );
    }

    #[test]
    fn visual_mode_moves_commits_cancels_and_ignores_the_rest() {
        let dir = tempfile::tempdir().unwrap();
        std::fs::write(dir.path().join("a"), b"").unwrap();
        let mut state = AppState::new(dir.path().to_owned()).unwrap();
        let mut ctx = InputCtx::default();
        assert_eq!(
            navigation(key(KeyCode::Char('v')), &mut ctx, &state),
            Some(Action::EnterVisual)
        );
        state.mode = crate::app::mode::Mode::Visual {
            anchor: state.entries[0].path.clone(),
        };

        let mut visual_key = |code| visual(key(code), &mut ctx, &state);
        assert_eq!(visual_key(KeyCode::Char('j')), Some(Action::MoveDown));
        assert_eq!(visual_key(KeyCode::Char('G')), Some(Action::JumpBottom));
        assert_eq!(
            visual_key(KeyCode::Char(' ')),
            Some(Action::CommitVisual(None))
        );
        assert_eq!(
            visual_key(KeyCode::Char('v')),
            Some(Action::CommitVisual(None))
        );
        assert_eq!(
            visual_key(KeyCode::Char('l')),
            Some(Action::CommitVisual(Some(Box::new(Action::EnterOrOpen))))
        );
        assert_eq!(visual_key(KeyCode::Esc), Some(Action::ExitMode));
        assert_eq!(
            visual_key(KeyCode::Char('q')),
            None,
            "no quitting mid-range"
        );
        assert_eq!(visual_key(KeyCode::Char('/')), None);
    }

    /// The maintainer types on Spanish (Latin America), where `@` is AltGr+Q
    /// and Windows reports AltGr as Ctrl+Alt. `@` has to work typed that way,
    /// with Shift (US English), and bare (a terminal that drops the modifier).
    #[test]
    fn at_repeats_the_last_command_on_every_layout() {
        let dir = tempfile::tempdir().unwrap();
        let state = AppState::new(dir.path().to_owned()).unwrap();
        let mut ctx = InputCtx::default();
        for modifiers in [
            KeyModifiers::CONTROL | KeyModifiers::ALT,
            KeyModifiers::SHIFT,
            KeyModifiers::NONE,
        ] {
            let at = KeyEvent {
                modifiers,
                ..key(KeyCode::Char('@'))
            };
            assert_eq!(
                navigation(at, &mut ctx, &state),
                Some(Action::RepeatLastCommand),
                "@ with {modifiers:?}"
            );
        }
    }

    /// AltGr must not make a character into a Ctrl chord — but a real Ctrl
    /// chord must stay one, or `Ctrl-c` would stop cancelling.
    #[test]
    fn altgr_is_text_and_ctrl_is_still_a_chord() {
        let event = |modifiers| KeyEvent {
            modifiers,
            ..key(KeyCode::Char('c'))
        };
        assert_eq!(
            key_to_config_string(event(KeyModifiers::CONTROL | KeyModifiers::ALT)),
            Some("c".to_owned())
        );
        assert_eq!(
            key_to_config_string(event(KeyModifiers::CONTROL)),
            Some("ctrl-c".to_owned())
        );
    }

    #[test]
    fn configured_binding_overrides_default_char() {
        let mut cfg = crate::config::load(None).unwrap();
        cfg.keymap
            .navigation
            .insert("move_down".to_owned(), "n".to_owned());
        let dir = tempfile::tempdir().unwrap();
        let state = AppState::with_config(dir.path().to_owned(), cfg).unwrap();
        let mut ctx = InputCtx::default();
        assert_eq!(
            navigation(key(KeyCode::Char('n')), &mut ctx, &state),
            Some(Action::MoveDown)
        );
    }
}