//! Every syntactic choice pardes makes, in one file: which key runs what,
//! which mouse button means what, how a looked-at word is SPELLED, and the
//! handful of layout numbers that are taste rather than structure.
//!
//! The point is the editing session, not the architecture: retargeting a key,
//! a chord or a piece of Look syntax is an edit HERE and nowhere else. Nothing
//! below is read at runtime from a file — this IS the config format, recompiled
//! — so a binding may be any comptime expression and a wrong one is a compile
//! error rather than a silent no-op.
//!
//! Order is deliberate. PART 1 is pardes's OWN vocabulary, the part a user
//! actually fiddles with, so it is where a reader lands. PART 2 is Look/Exec
//! syntax. PART 3 is the helix keymap, which is under a differential-testing
//! contract — see the banner there before touching it.
//!
//! What is NOT a binding: a named key's own identity. Insert mode's Backspace,
//! Delete, Enter and Tab are dispatched on `Key.<name>` in handleInsert and
//! stay there — Backspace deleting backwards is what the key IS, not a choice
//! anyone remaps. `Ctrl-w` deleting a word backwards is a choice, and it is
//! here.
const std = @import("std");
const pardes = @import("pardes.zig");
const builtins = @import("builtins.zig");
const Key = pardes.Key;
const Mouse = pardes.Mouse;
const Builtin = builtins.Builtin();

/// One key press a binding matches. `shift` is only consulted when a binding
/// ASKS for it: shift is already carried in the codepoint for anything
/// printable (`A` is `A`, not shift-`a`), so the one chord that needs the flag
/// is Shift-Esc, on a key that has no shifted codepoint. pardes.zig's `hit`
/// is the matcher.
pub const Chord = struct {
    cp: u21,
    ctrl: bool = false,
    alt: bool = false,
    shift: bool = false,
};

// A binding is a LIST because most have two spellings that must reach the same
// arm — a letter and an arrow, `Ctrl-f` and PageDown. One list, one dispatch
// site; the `or` chains this replaces had the modifier logic written out three
// ways (the old is/isC/isA).

// ============================================================================
// PART 1 — pardes's own bindings. Nothing here is inherited from anywhere;
// these are the ones to fiddle with.
// ============================================================================

// ---- the SPC leader ----

/// opens the leader: a key path from here runs a BUILTIN with no arguments.
/// Body normal mode only — a tag is always insert, and a tty pane's keys
/// belong to the program.
pub const leader: []const Chord = &.{.{ .cp = ' ' }};

/// Help's key, honored at ANY depth: it lists what the prefix typed so far can
/// still reach. Also Help's own path below, so the character is spelled once.
pub const leader_help: u8 = '?';

/// what an unlisted builtin's path is until someone says otherwise: a value no
/// key path can be, so the loop at the bottom of the table can refuse it
const undecided: []const u8 = "<undecided>";

/// SPC leader: ONE key path per builtin, the whole remapping surface. A new
/// enum field is a compile error until someone has DECIDED its path — that is
/// what `undecided` and the loop under the table are for, and it used to be
/// EnumArray.init's own doing (it demands every field). It cannot be any more:
/// the gui-only builtins are not fields of this literal's type on tty or web,
/// so the literal cannot name them and a default is the only way to have both.
/// Groups are just shared first letters (f files, h docs, c columns, t
/// toggles, s session, l language, w windows).
///
/// `null` = this builtin's shortcut is not a leader path. Look and Exec are
/// the two: their shortcuts are Enter/Tab and the two mouse buttons below, and
/// a third spelling under SPC would be a key that does nothing you cannot
/// already do with the key your hand is on. The option is the honest type —
/// "every builtin has a leader path" was only ever true by accident.
pub const leader_path = paths: {
    var table = std.EnumArray(Builtin, ?[]const u8).initDefault(@as(?[]const u8, undecided), .{
        .Help = &[_]u8{leader_help},
        // The whole LANGUAGE group lives under `l`, and pardes's own builtins keep
        // the letters they always had — `SPC d` is Del, `SPC k` is Kill.
        //
        // Helix puts these on bare `<space>` letters, and an earlier pass followed
        // it there, which cost `d`, `k`, `s`, `h` and the session group. That is
        // the wrong trade: those five are pardes's most-pressed keys and predate
        // the language work, whereas an LSP command is something you reach for
        // deliberately and can afford one more keystroke. Each one still keeps
        // HELIX'S OWN LETTER inside the group, so the mapping is `<space>X` ->
        // `SPC l X` with nothing to re-learn but the prefix.
        //
        // The five GOTOS are untouched and remain exactly helix's — `gd` `gD` `gy`
        // `gi` `gr`, plus `]d`/`[d` and `=`. Those never collided with anything, so
        // there was never a reason to move them. They are in PART 3.
        .Hover = "lk",
        .Rename = "lr",
        .CodeAction = "la",
        .SelectRefs = "lh",
        .Symbols = "ls",
        .WsSymbols = "lS",
        .Diagnostics = "ld",
        .WsDiagnostics = "lD",
        .Lspinfo = "li",
        .Lspwhy = "lw",
        .Del = "d",
        .Kill = "k",
        // the `f` file group (spacemacs): Save left vim's `w` to join Find here,
        // which frees `w` for the window group (SPC w h/j/k/l) to move into.
        .Save = "fs",
        .Find = "ff",
        .Grep = "fg",
        .Tutor = "ht",
        .Newcol = "cn",
        .Delcol = "cd",
        .Debug = "td",
        .Colors = "tc",
        .NextColor = "tn",
        .Crt = "tr",
        // the theme picker joins the toggles it belongs with; `Theme` itself takes
        // a NAME, and a key path can never carry one, so it has none (the same
        // reason Look and Exec have none)
        .ThemeSel = "tt",
        .Theme = null,
        // the image toggles join the same `t` group; Palette takes `l` because
        // `p` is Petscii's and `c` is Colors'.
        .Petscii = "tp",
        .Palette = "tl",
        .Ascii = "ta",
        .Dump = "sd",
        .Restore = "sr",
        // the `w` window group `Save` vacated: the four directional focus moves
        // the Ctrl-w prefix does, spelled h/j/k/l because focus IS a motion, plus
        // `t` for the file<->terminal hop.
        .Left = "wh",
        .Down = "wj",
        .Up = "wk",
        .Right = "wl",
        .Toggleterm = "wt",
        // the `j` JUMP group, its own letter rather than more of `w`: the window
        // group moves focus by GEOMETRY (the pane left of this one), these move it
        // by TIME (the pane I was in before). `o` and `i` are the letters of the
        // chords that do the same thing, `jj` is the group's obvious verb, and
        // `jl` is the list itself.
        .Back = "jo",
        .Forward = "ji",
        .Last = "jj",
        .Jumplist = "jl",
        // the two acme verbs: keys and buttons, no leader path — see above
        .Look = null,
        .Exec = null,
    });
    // The GUI's two font builtins, in the same `t` group as the theme picker
    // they mirror — but set here rather than named above, because on tty and
    // web they are not builtins at all (see builtins.zig) and the literal's
    // type has no field to write. `Font` takes a NAME, so it has no path, for
    // the same reason `Theme` has none.
    if (pardes.platform == .gui) {
        table.set(.FontSel, "tf");
        table.set(.Font, null);
    }
    // PdfFit exists only in MuPDF builds (its run declaration deliberately
    // changes shape when the feature is off), so name its toggle path through
    // the same comptime branch rather than making feature-off enums mention it.
    if (pardes.pdf_enabled) table.set(.PdfFit, "tz");
    // ...and the property EnumArray.init used to give for free: every builtin
    // this build HAS is a builtin someone decided a path (or a null) for.
    for (std.enums.values(Builtin)) |b| if (table.get(b)) |p| {
        if (std.mem.eql(u8, p, undecided)) @compileError("builtin has no leader path decided: " ++ @tagName(b));
    };
    break :paths table;
};

// ---- the acme chords ----

// Look and Execute, the two verbs the whole environment is built on. Each has
// a KEY and a mouse BUTTON, and they are the same two verbs: Enter on a word
// does what a right click on it does. Swap the two `_key` lines for the vim
// reading, where Enter runs the command line. (This pair replaced a
// `swap_enter_tab` bool, which could only ever exchange them — two bindings
// can also be moved somewhere else entirely.)
pub const look_key: []const Chord = &.{.{ .cp = Key.enter }};
pub const exec_key: []const Chord = &.{.{ .cp = Key.tab }};
pub const look_button: Mouse.Button = .right;
pub const exec_button: Mouse.Button = .middle;
/// sweep, focus, place the cursor, and the left half of every acme chord
pub const select_button: Mouse.Button = .left;

/// ...and WHAT those four run. Look and Exec are ORDINARY builtins — the same
/// kind of thing Save and Grep are, executable by name wherever text lives
/// (`Look main.zig` in a tag does what a right click on `main.zig` does) — so
/// the four bindings above are bindings like any other, and these two lines
/// are the whole of what makes them special. Point `look_cmd` at `.Grep` and
/// Enter greps.
pub const look_cmd: Builtin = .Look;
pub const exec_cmd: Builtin = .Exec;

// ---- windows ----

/// helix's window prefix. It stays despite `SPC w` covering the same four
/// builtins because it reaches one place the leader cannot: a pane in raw tty
/// mode never sees SPC (the shell owns every printable key), so this is the
/// only keyboard way out of one.
pub const window_prefix: []const Chord = &.{.{ .cp = 'w', .ctrl = true }};

/// The four directional focus moves, as data: `Ctrl-w <letter|arrow>` in a
/// body, and the bare LETTER on a focused tagline, where focus IS the motion
/// (the arrows stay grapheme motion inside the tag, which is why the two
/// spellings are separate fields rather than one list). One table, two
/// readers — and the `cmd` column is what makes the chord discoverable from
/// the builtin as well as the other way round.
pub const window_keys = [_]struct { letter: Chord, arrow: Chord, cmd: Builtin }{
    .{ .letter = .{ .cp = 'h' }, .arrow = .{ .cp = Key.left }, .cmd = .Left },
    .{ .letter = .{ .cp = 'j' }, .arrow = .{ .cp = Key.down }, .cmd = .Down },
    .{ .letter = .{ .cp = 'k' }, .arrow = .{ .cp = Key.up }, .cmd = .Up },
    .{ .letter = .{ .cp = 'l' }, .arrow = .{ .cp = Key.right }, .cmd = .Right },
};

/// global window ops, live in ANY mode (which is why they are Alt-, not a
/// leader path): a new terminal below, and moving this terminal into a fresh
/// column. Alt-c is a deliberate divergence from helix's change-noyank —
/// hxdiff waives it by name.
pub const new_shell_below: []const Chord = &.{.{ .cp = 'n', .alt = true }};
pub const pane_to_new_column: []const Chord = &.{.{ .cp = 'c', .alt = true }};

// ---- jumps ----

/// vim's Ctrl-o / Ctrl-i, walking the focus history back and forward. Global
/// in any mode, like the two Alt- ops above and for the same reason: getting
/// BACK has to work from inside a pane that owns its keys.
///
/// CAREFUL, and this is why the table has a comment: **Ctrl-i is Tab**. On the
/// wire they are the same byte (0x09), so on a host that speaks only the
/// legacy encoding this binding never fires and 0x09 keeps meaning `exec_key`
/// below — which is the right way round, since Tab-executes is the older and
/// more used of the two. Where the host speaks the kitty keyboard protocol
/// (`CSI 105;5u`) the two are distinct keys and both work. Shift-Esc
/// (tty_toggle_alt) is already spelled on that same bet.
///
/// Shaped like window_keys: the `cmd` column is what makes the chord
/// discoverable from the builtin as well as the other way round, and it is
/// what keeps ONE implementation — pressing the chord and executing the word
/// `Back` are the same call.
pub const jump_keys = [_]struct { chord: Chord, cmd: Builtin }{
    .{ .chord = .{ .cp = 'o', .ctrl = true }, .cmd = .Back },
    .{ .chord = .{ .cp = 'i', .ctrl = true }, .cmd = .Forward },
};

/// `j` off the topbar drops back onto a tagline — the mirror of the `k` that
/// got you there (window_keys' letter, answered by tagNormalKey).
pub const topbar_down: []const Chord = &.{.{ .cp = 'j' }};
/// the topbar has no neighbouring window to walk to, so up here h/l are plain
/// grapheme motion instead
pub const topbar_left: []const Chord = &.{.{ .cp = 'h' }};
pub const topbar_right: []const Chord = &.{.{ .cp = 'l' }};

// ---- raw tty mode ----

/// Ctrl-<this> toggles raw tty mode in and out (terminals only); tty is
/// deliberately off the normal editing path. Not a Chord because the shell can
/// override it at runtime (`--tty-toggle`), so this is only Options' default.
pub const tty_toggle_default: u21 = 'b';
/// the second spelling, for hosts that report modifiers on Escape (the kitty
/// keyboard protocol). Where they don't it arrives as a plain Escape and still
/// means what Escape always means.
pub const tty_toggle_alt: []const Chord = &.{.{ .cp = Key.escape, .shift = true }};

// ---- the tag line and the topbar ----

// The topbar is a HAND-PICKED subset in a fixed order, not a derivation: row 0
// is where topbar clicks land, so its exact bytes are load-bearing (every
// snapshot golden records the column each word starts at). Comptime-checked
// against the enum in pardes.zig so a rename cannot silently rot it.
// Colors and Crt are NOT here: both are set-once display switches you flip and
// forget, and a bar you read every frame should not spend width on them now
// that `SPC t c` / `SPC t r` press them. NextColor stays — it is the one you
// cycle repeatedly, so a click beats a three-key path.
//
// Help is LAST and is the one word that has to be here. A bare `pardes` boots
// straight into tty mode (main.zig: `args.len == 1`), where every printable
// key belongs to the shell — so SPC never reaches the leader and `SPC ?`, the
// thing that would tell you the leader exists, is exactly what you cannot
// press. Row 0 is not a pane, so a middle-click on it is dispatched before any
// pane's mode is consulted: this word works in tty mode, which is the only
// reason it earns the width. Appended rather than inserted so every existing
// word keeps its column and no golden's click coordinates move.
//
// The two searches go LAST (before the optional `Restore <path>`), and next to
// each other: they are one pair — Find matches file NAMES, Grep their CONTENTS.
pub const topbar_str = "Kill Newcol Tutor Debug NextColor Dump Find Grep Help";

/// the default editable tail of a pane's tag, per kind (an output buffer has
/// no file to Save, so it gets the plain one)
pub const pane_builtins_str = "Del";
pub const file_pane_builtins_str = "Save Del";

/// the pane's mode, as ONE character in the layout box at its top-left — live
/// chrome, not text you own. It used to be a three-letter word leading every
/// tagline; the box was already there carrying no information at all, so the
/// mode moved into it and the taglines got their four columns back.
///
/// These are NOT the initials. A badge you read at a glance every time your
/// eye crosses a pane should LOOK like what it means, and each of these is a
/// mark that already means its mode somewhere else: `^` is the proofreader's
/// caret, the mark that says text goes in HERE; `$` is the shell prompt, and a
/// pane wearing it has the keyboard wired straight to the program on the other
/// end; `•` is the pane at rest, a full stop, nothing waiting to eat what you
/// type. (The caret's true form is `‸` U+2038 and the ASCII `^` is only its
/// stand-in — but `^` is in every font ever made and `‸` is in about four, and
/// a mode badge that renders blank on someone's terminal is worse than one
/// spelled with the near-miss.)
///
/// ONE CODEPOINT each. The box prints a single cell, so a two-character string
/// here would be pushed into one cell as a single grapheme and come out wrong.
/// A font missing the glyph draws a blank box, which is exactly what the box
/// drew before there was anything in it.
pub const tag_normal = " ";
pub const tag_insert = "^";
pub const tag_tty = "$";
/// ...and `img` stays a WORD at the head of an image pane's tagline, because
/// it is not a mode: it says what the pane IS, which no amount of watching the
/// box will tell you. The box on an image pane still shows its mode.
pub const tag_image = "img";

/// on a focused tag: yank what the chord would run (the selection, else the
/// word under the cursor). The path is selectable, so this is how you copy it.
pub const tag_yank: []const Chord = &.{.{ .cp = 'y' }};

// ---- the command line and search ----

/// vim's command line with acme's vocabulary: focus the pane's own tag in
/// normal mode, parked at the tail's start, and the execute chord runs the
/// word under the cursor (`:w<Tab>` = Save).
pub const command_line: []const Chord = &.{.{ .cp = ':' }};

/// `/` types a pattern into the tag; n/N walk the results. Same keys on every
/// kind of pane — a terminal with no search armed falls back to n/N as a
/// motion over the lookable tokens in its output.
///
/// Helix's letters, but NOT helix's commands (it searches by regex and pardes
/// has no regex engine), so these three sit out here rather than under the
/// contract in PART 3 — the differential suites never press them.
pub const search: []const Chord = &.{.{ .cp = '/' }};
pub const search_next: []const Chord = &.{.{ .cp = 'n' }};
pub const search_prev: []const Chord = &.{.{ .cp = 'N' }};
/// Enter on an armed search input runs it; `escape` (PART 3) abandons it.
pub const search_submit: []const Chord = &.{.{ .cp = Key.enter }};

// ---- mouse ----

/// wheel step, in rows / in columns. The horizontal step is bigger because a
/// column is narrower than a row is tall and a wheel tick should move a
/// comparable distance either way.
pub const wheel_rows: i32 = 1;
pub const wheel_cols: i32 = 4;

/// Touchpad drift guard, in ticks. A two-finger swipe that is MEANT to be
/// vertical carries a little sideways drift, and the pad faithfully turns that
/// drift into wheel_left/wheel_right — so a plain scroll slides the view
/// sideways under you. Every vertical tick re-arms the guard to this many
/// ticks and every horizontal tick spends one instead of scrolling, which
/// makes horizontal EARN its way back: it has to land this many ticks in a row
/// with no vertical among them. 3, because drift arrives in ones and twos —
/// at 1 or 2 a doubled drift tick mid-swipe still gets through, and much
/// higher starts eating deliberate swipes. Set 0 to disable the heuristic.
///
/// It costs nothing at rest: the guard is only armed by vertical scrolling, so
/// a horizontal swipe that starts from a still view moves on its FIRST tick.
/// Note this applies to a tilt wheel too, where "recent vertical" is a much
/// weaker signal of accident — a mouse would rather not have it. Living with
/// that is deliberate: the only honest fix is a per-device flag out of the
/// shell (libinput/SDL know which is which, vaxis does not), and paying for a
/// device-detection layer to spare a tilt wheel three clicks after a scroll is
/// a worse trade than the three clicks.
pub const wheel_guard_ticks: u8 = 3;

/// The whole guard, as one state machine, so it can be tested as one thing:
/// fold a wheel tick into `guard` and answer whether it scrolls. The core owns
/// the counter (Pardes.wheel_guard) because the gesture belongs to the DEVICE,
/// not to whichever pane the pointer happens to sit over.
pub fn wheelTick(guard: *u8, vertical: bool) bool {
    if (vertical) {
        guard.* = wheel_guard_ticks;
        return true;
    }
    if (guard.* == 0) return true;
    guard.* -= 1;
    return false;
}

// written to hold for ANY tuning of wheel_guard_ticks, since tuning it by hand
// is what this file is for — a test that pinned the number 3 would just be a
// second place to edit it
test "wheel drift guard" {
    var g: u8 = 0;
    // from rest, horizontal moves on the first tick — nothing to prove
    try std.testing.expect(wheelTick(&g, false));
    try std.testing.expect(wheelTick(&g, false));
    if (wheel_guard_ticks == 0) return; // guard disabled: nothing left to check
    // a vertical swipe with drift mixed in: every sideways tick is swallowed,
    // because each vertical tick re-arms the guard in full
    for (0..4) |_| try std.testing.expect(wheelTick(&g, true));
    try std.testing.expect(!wheelTick(&g, false));
    try std.testing.expect(wheelTick(&g, true));
    try std.testing.expect(!wheelTick(&g, false));
    // the deliberate horizontal swipe that follows pays off the rest of the
    // guard tick by tick, then runs free
    for (1..wheel_guard_ticks) |_| try std.testing.expect(!wheelTick(&g, false));
    try std.testing.expect(wheelTick(&g, false));
    try std.testing.expect(wheelTick(&g, false));
}

// ---- layout numbers that are taste ----

/// the file pane's line-number gutter, in columns
pub const PREFIX_W: u16 = 5;
/// vim 'scrolloff': keyboard cursor moves keep this many context rows visible
/// above/below the cursor (clamped at file boundaries and short panes), and
/// the same count of COLUMNS horizontally
pub const scroll_off = 3;
/// the pane's left chrome: scrollbar + the layout box in the tag row. The
/// scrollbar PAINTS only the first of these columns; the second is the pane's
/// own background, so the bar reads as one column with a column of page
/// between it and the text. Layout is untouched by that — the gutter is still
/// GUTTER columns and a click anywhere in them still scrolls; only the ink
/// narrowed. A half-block glyph in the second column was tried and rejected.
pub const GUTTER: u16 = 2;
/// a pane never shrinks past this (the h-handle can still take it to its tag
/// row alone, which is BOX_H and a structural fact, not this)
pub const MINW: u16 = 10;
pub const MINH: u16 = 3;

// ============================================================================
// PART 2 — Look/Exec syntax: how a click on text is SPELLED. What the
// resolution then DOES with it is look.zig.
// ============================================================================

/// file-ish word chars (acme's isfilec): alnum + these. This set is the whole
/// definition of "the word under the cursor" for Look, Execute, the tag chord
/// and every search result row.
pub fn isFileChar(c: u8) bool {
    return std.ascii.isAlphanumeric(c) or switch (c) {
        '.', '-', '+', '/', ':', '@', '_', '~' => true,
        else => false,
    };
}

/// `` @`ls -la` `` — a word that names a COMMAND to run rather than a file to
/// open. Both halves are named here because they are a CHOICE: the `@` marks
/// it as ours (it is already a file char, so it can never split a path) and
/// the backquotes hold a command line with spaces in it, which is the whole
/// point — a file-ish word cannot. Respell them here and nowhere else.
pub const cmd_open = "@`";
pub const cmd_close: u8 = '`';

/// The command inside `` @`...` ``, or null when `w` is not one.
pub fn commandWord(w: []const u8) ?[]const u8 {
    if (w.len <= cmd_open.len or !std.mem.startsWith(u8, w, cmd_open)) return null;
    if (w[w.len - 1] != cmd_close) return null;
    return w[cmd_open.len .. w.len - 1];
}

/// The bounds of the word at `col` in `line` — THE expansion a no-drag
/// look/execute click and the tag chord both use.
///
/// A `` @`...` `` run is taken WHOLE and wins outright: a backtick is not a
/// file char, so the plain scan below would stop dead inside one and hand a
/// look the fragment `ls` out of `` @`ls -la` ``. Acme does exactly this for
/// its own `<`/`|`/`>` command words. Otherwise it is the file-ish word.
pub fn wordBounds(line: []const u8, col: usize) struct { lo: usize, hi: usize } {
    var i: usize = 0;
    while (std.mem.indexOfPos(u8, line, i, cmd_open)) |o| {
        const close = std.mem.indexOfScalarPos(u8, line, o + cmd_open.len, cmd_close) orelse break;
        if (col >= o and col <= close) return .{ .lo = o, .hi = close + 1 };
        i = close + 1;
    }
    var lo = col;
    while (lo > 0 and isFileChar(line[lo - 1])) lo -= 1;
    var hi = col;
    while (hi < line.len and isFileChar(line[hi])) hi += 1;
    return .{ .lo = lo, .hi = hi };
}

/// separates a path from its LINE and COL: `main.zig:100:7`. Must be a member
/// of isFileChar or the suffix would not be part of the word in the first
/// place.
pub const line_col_sep: u8 = ':';

/// ...and separates that spot from the END of a RANGE. A look at a ranged path
/// SELECTS the span rather than just parking on its first cell, which is what
/// lets a search result carry the text it matched and `n` land ON it.
///
/// Three spellings. The long one subsumes the other two, but the short ones
/// are what a person actually types and what a grep-alike emits, so all three
/// parse:
///     main.zig:412-418        lines 412 through 418, whole
///     main.zig:412:9-21       line 412, columns 9 through 21
///     main.zig:412:9-418:1    line 412 column 9 through line 418 column 1
/// Both ends are INCLUSIVE and 1-based, like the spot they extend — `412-418`
/// reads as seven lines, not six. `main.zig:412` and `main.zig:412:9` keep
/// meaning exactly what they always did.
///
/// Must be an isFileChar member, same as the separator above, or a click would
/// expand to half a range. That is also why reading it is FUSSY (look.zig,
/// parsePathLine): ordinary paths are full of dashes, so the suffix counts as
/// a range only when a NUMBER follows the dash — `my-file:10` and `build-2`
/// stay the paths they are.
pub const range_sep: u8 = '-';

/// `@p7:10:5` — pane 7, line 10, column 5. The one look target that names a
/// live pane instead of a path, because terminals and output buffers have no
/// file for a location to point at. Both the writer (a `/` result row) and the
/// reader (look.resolve) spell it from here.
pub const pane_addr = "@p";

/// a word starting with one of these is a URL and leaves the app entirely: no
/// filesystem can answer it
pub const url_schemes = [_][]const u8{ "http://", "https://" };

/// a path ending in one of these opens an image pane instead of a file pane
pub const image_exts = [_][]const u8{ ".png", ".jpg", ".jpeg", ".gif", ".bmp", ".ppm", ".pgm", ".tga" };

/// What `Ctrl-c` (comment_toggle) puts at the front of a line, by file
/// EXTENSION — which is how src/syntax.zig already tells one language from
/// another, so this is that same notion and not a second one. A pane whose
/// path matches nothing here (and every terminal, which has no path at all)
/// gets `comment_token_default`.
///
/// `#` as the default is not a guess: it is helix's own DEFAULT_COMMENT_TOKEN,
/// which is what a helix buffer with no language configured comments with —
/// and therefore what the differential oracle answers, since the harness runs
/// with zero language configs.
/// Languages with no LINE comment at all (css, html, json, ocaml) are absent
/// on purpose: helix leaves those buffers on its default too, and inventing a
/// token for them would be a divergence nothing asked for.
pub const comment_token_default = "#";
pub const comment_tokens: []const struct { exts: []const []const u8, token: []const u8 } = &.{
    .{ .token = "//", .exts = &.{ ".zig", ".zon", ".c", ".h", ".cpp", ".cc", ".cxx", ".hpp", ".hh", ".hxx", ".rs", ".go", ".java", ".scala", ".sc", ".kt", ".kts", ".cs", ".csx", ".php", ".pas", ".pp", ".p", ".js", ".jsx", ".mjs", ".cjs", ".ts", ".tsx", ".swift", ".dart" } },
    .{ .token = "#", .exts = &.{ ".py", ".pyw", ".sh", ".bash", ".zsh", ".rb", ".rake", ".ex", ".exs", ".ps1", ".psm1", ".psd1", ".pl", ".pm", ".r", ".jl", ".nix", ".toml", ".yaml", ".yml", ".cmake", ".mk", ".tf" } },
    .{ .token = "--", .exts = &.{ ".lua", ".hs", ".lhs", ".elm", ".sql", ".adb", ".ads", ".ada" } },
    .{ .token = ";", .exts = &.{ ".clj", ".cljs", ".cljc", ".edn", ".el", ".lisp", ".scm", ".asm", ".s" } },
    .{ .token = "%", .exts = &.{ ".erl", ".hrl", ".tex", ".cls", ".sty" } },
    .{ .token = "!", .exts = &.{ ".f", ".for", ".ftn", ".f90", ".f95", ".f03", ".f08" } },
    .{ .token = "\"", .exts = &.{ ".vim", ".vimrc" } },
};

/// What an armed search writes into the tag tail — and the ONLY record of
/// which search it is: Enter reads the marker back (submitSearch) instead of
/// pardes carrying a second piece of pane state per command. The pattern is
/// everything past the `/`, so a pattern may itself contain slashes; the word
/// before it is the builtin's own name, so the armed tag reads as the command
/// it will run. The bare `/` has no name — it searches the pane itself.
pub const search_marker = " /";
pub const find_marker = " Find /";
pub const grep_marker = " Grep /";
pub const rename_marker = " Rename /";
pub const symbol_marker = " WsSymbols /";
/// helix `s` / `S`. The only two markers whose word is NOT a builtin — there
/// is no Select/Split command to run from a tag, they name the key that armed
/// the input so the tag still reads as what it is about to do. They also mark
/// the one input that previews as you type (pardes.zig, previewSelRegex).
pub const select_marker = " Select /";
pub const split_marker = " Split /";

/// Output-buffer names (acme's +Errors). Cosmetic now, and deliberately so: a
/// buffer is DERIVED from the command that opened it (output_pane.traits), and
/// nothing identifies one by matching this text any more — renaming any of
/// these changes only what you read in a tag.
pub const search_buffer = "+Search";
pub const help_buffer = "+Help";
pub const jumps_buffer = "+Jumps";
pub const themes_buffer = "+Themes";
pub const fonts_buffer = "+Fonts";
pub const hover_buffer = "+Hover";
pub const lsp_buffer = "+Lsp";

// ============================================================================
// PART 3 — THE HELIX KEYMAP. READ THIS BEFORE RETARGETING ANYTHING BELOW.
//
// These are not free choices. `zig build hxdiff` (360 cases) and
// `zig build hxparity` (440 cases) are DIFFERENTIAL suites: they drive a real
// helix and this core with the same keystrokes and compare the results, and a
// mismatch is a failure, not a diff to accept. Moving a key here therefore
// breaks the build until the divergence is written down as a waiver with a
// reason — which is the correct workflow for a DELIBERATE divergence (Alt-c
// above is one) and an alarm for an accidental one.
//
// Everything in PART 1 is outside that contract and free to move.
// ============================================================================

// ---- modal prefixes ----

// These are STORED — pane.pending / pending2 / find_op hold the codepoint
// ITSELF until the next key completes the sequence, and the continuation reads
// it back — so they are bare codepoints rather than Chords, and pardes.zig
// matches them with `isPrefix` instead of `hit`. A prefix must therefore be an
// unmodified printable key. Untyped so they compare against both the u21 and
// the u8 fields that hold them.
pub const goto_prefix = 'g';
pub const view_prefix = 'z';
pub const match_prefix = 'm';
pub const replace_prefix = 'r';
pub const next_prefix = ']';
pub const prev_prefix = '[';
// f/F/t/T: the stored byte IS the operator — `f`/`t` mean forward and `t`/`T`
// mean stop short — so the four are read back as values, not just matched.
pub const find_char_fwd = 'f';
pub const find_char_back = 'F';
pub const till_char_fwd = 't';
pub const till_char_back = 'T';
/// repeat the last f/F/t/T
pub const repeat_find: []const Chord = &.{.{ .cp = '.', .alt = true }};

// ---- motion ----

pub const move_left: []const Chord = &.{ .{ .cp = 'h' }, .{ .cp = Key.left } };
pub const move_right: []const Chord = &.{ .{ .cp = 'l' }, .{ .cp = Key.right } };
pub const move_down: []const Chord = &.{ .{ .cp = 'j' }, .{ .cp = Key.down } };
pub const move_up: []const Chord = &.{ .{ .cp = 'k' }, .{ .cp = Key.up } };
pub const next_word_start: []const Chord = &.{.{ .cp = 'w' }};
pub const prev_word_start: []const Chord = &.{.{ .cp = 'b' }};
pub const next_word_end: []const Chord = &.{.{ .cp = 'e' }};
pub const next_long_word_start: []const Chord = &.{.{ .cp = 'W' }};
pub const prev_long_word_start: []const Chord = &.{.{ .cp = 'B' }};
pub const next_long_word_end: []const Chord = &.{.{ .cp = 'E' }};
pub const line_start: []const Chord = &.{ .{ .cp = '0' }, .{ .cp = Key.home } };
pub const line_end: []const Chord = &.{ .{ .cp = '$' }, .{ .cp = Key.end } };
pub const line_first_nonws: []const Chord = &.{.{ .cp = '^' }};
/// helix goto_line: only acts WITH a count (bare G is a no-op; `ge` is
/// goto-last-line)
pub const goto_line: []const Chord = &.{.{ .cp = 'G' }};
/// grapheme motion in a ONE-LINE context (a tag, the topbar): the arrows only.
/// A tagline spends h/l on the layout (window_keys) and the topbar answers
/// them itself (topbar_left/right), so the letters are not in this vocabulary.
pub const line_move_left: []const Chord = &.{.{ .cp = Key.left }};
pub const line_move_right: []const Chord = &.{.{ .cp = Key.right }};

// ---- paging and the view ----

pub const half_page_down: []const Chord = &.{.{ .cp = 'd', .ctrl = true }};
pub const half_page_up: []const Chord = &.{.{ .cp = 'u', .ctrl = true }};
pub const page_down: []const Chord = &.{ .{ .cp = 'f', .ctrl = true }, .{ .cp = Key.page_down } };
pub const page_up: []const Chord = &.{ .{ .cp = 'b', .ctrl = true }, .{ .cp = Key.page_up } };
/// under `z`: put the cursor's line at the top / centre / bottom of the view
pub const view_top: []const Chord = &.{.{ .cp = 't' }};
pub const view_center: []const Chord = &.{ .{ .cp = 'z' }, .{ .cp = 'c' } };
pub const view_bottom: []const Chord = &.{.{ .cp = 'b' }};
/// under `z`: scroll the view one line, cursor snapped to the scrolloff edge
pub const view_scroll_down: []const Chord = &.{ .{ .cp = 'j' }, .{ .cp = Key.down } };
pub const view_scroll_up: []const Chord = &.{ .{ .cp = 'k' }, .{ .cp = Key.up } };

// ---- under `g` (goto) ----

pub const goto_file_start: []const Chord = &.{.{ .cp = 'g' }};
pub const goto_last_line: []const Chord = &.{.{ .cp = 'e' }};
pub const goto_line_start: []const Chord = &.{.{ .cp = 'h' }};
pub const goto_line_end: []const Chord = &.{.{ .cp = 'l' }};
pub const goto_first_nonws: []const Chord = &.{.{ .cp = 's' }};
pub const goto_line_down: []const Chord = &.{.{ .cp = 'j' }};
pub const goto_line_up: []const Chord = &.{.{ .cp = 'k' }};
pub const goto_column: []const Chord = &.{.{ .cp = '|' }};
/// view-relative rows (helix goto_window)
pub const goto_view_top: []const Chord = &.{.{ .cp = 't' }};
pub const goto_view_center: []const Chord = &.{.{ .cp = 'c' }};
pub const goto_view_bottom: []const Chord = &.{.{ .cp = 'b' }};
// helix's five LSP gotos, all under `g` and nowhere else. They are motions,
// not builtins — a motion has no business being a word you can middle-click,
// which is why they are not in the language group under `SPC l`.
pub const goto_definition: []const Chord = &.{.{ .cp = 'd' }};
pub const goto_declaration: []const Chord = &.{.{ .cp = 'D' }};
pub const goto_type_definition: []const Chord = &.{.{ .cp = 'y' }};
pub const goto_implementation: []const Chord = &.{.{ .cp = 'i' }};
pub const goto_references: []const Chord = &.{.{ .cp = 'r' }};

// ---- under `m` (match) ----

/// `mm` acts at once, so it is an ordinary chord
pub const match_bracket: []const Chord = &.{.{ .cp = 'm' }};
// The other five are SUB-prefixes: each waits for a textobject or surround
// character (`mi(`, `mr[{`), so pardes stores them the way it stores `m` and
// they are bare codepoints for the same reason as the block above.
pub const match_inside = 'i';
pub const match_around = 'a';
pub const surround_add = 's';
pub const surround_replace = 'r';
pub const surround_delete = 'd';

// ---- under `]` / `[` ----

pub const goto_paragraph: []const Chord = &.{.{ .cp = 'p' }};
pub const add_newline: []const Chord = &.{.{ .cp = ' ' }};
/// step the diagnostics list, asking for one if it is not up yet
pub const goto_diagnostic: []const Chord = &.{.{ .cp = 'd' }};
/// ]D / [D — the last / the first
pub const goto_diagnostic_end: []const Chord = &.{.{ .cp = 'D' }};

// ---- insert entry ----

pub const insert: []const Chord = &.{.{ .cp = 'i' }};
pub const append: []const Chord = &.{.{ .cp = 'a' }};
pub const insert_line_start: []const Chord = &.{.{ .cp = 'I' }};
pub const insert_line_end: []const Chord = &.{.{ .cp = 'A' }};
pub const open_below: []const Chord = &.{.{ .cp = 'o' }};
pub const open_above: []const Chord = &.{.{ .cp = 'O' }};

// ---- selection ----

pub const select_mode: []const Chord = &.{.{ .cp = 'v' }};
pub const select_line: []const Chord = &.{.{ .cp = 'x' }};
pub const select_line_bounds: []const Chord = &.{.{ .cp = 'X' }};
pub const shrink_to_line_bounds: []const Chord = &.{.{ .cp = 'x', .alt = true }};
pub const collapse_selection: []const Chord = &.{.{ .cp = ';' }};
pub const flip_selection: []const Chord = &.{.{ .cp = ';', .alt = true }};
pub const select_all: []const Chord = &.{.{ .cp = '%' }};

// ---- multiple cursors ----
//
// helix's Selection is a LIST of ranges with a primary index, and these ten
// keys are the ones that act on the list rather than on the text: every other
// key is replayed once per range instead (pardes.zig, replaySels). Alt-C is
// Alt-SHIFT-c and so does not collide with pane_to_new_column's Alt-c — `hit`
// compares the codepoint, and `C` is `C`.
pub const copy_sel_below: []const Chord = &.{.{ .cp = 'C' }};
pub const copy_sel_above: []const Chord = &.{.{ .cp = 'C', .alt = true }};
pub const keep_primary_sel: []const Chord = &.{.{ .cp = ',' }};
pub const remove_primary_sel: []const Chord = &.{.{ .cp = ',', .alt = true }};
pub const rotate_sel_fwd: []const Chord = &.{.{ .cp = ')' }};
pub const rotate_sel_back: []const Chord = &.{.{ .cp = '(' }};
pub const split_sel_newline: []const Chord = &.{.{ .cp = 's', .alt = true }};
pub const merge_sels: []const Chord = &.{.{ .cp = '-', .alt = true }};
pub const merge_consecutive_sels: []const Chord = &.{.{ .cp = '_', .alt = true }};
pub const trim_sels: []const Chord = &.{.{ .cp = '_' }};

// The other two list-making keys: a REGEX turns each range into many. Both
// arm the tag input above (select_marker / split_marker) instead of doing
// anything immediately, so `s` and `S` are the only normal-mode keys whose
// effect lands a keystroke later, on Enter — or live, as you type.
// `s` is free here despite `gs` (goto_first_nonws) also being `s`: a pending
// prefix is matched by the stored codepoint, never by these chords.
pub const select_regex: []const Chord = &.{.{ .cp = 's' }};
pub const split_regex: []const Chord = &.{.{ .cp = 'S' }};

// ---- edits ----

pub const delete: []const Chord = &.{.{ .cp = 'd' }};
pub const delete_noyank: []const Chord = &.{.{ .cp = 'd', .alt = true }};
pub const change: []const Chord = &.{.{ .cp = 'c' }};
pub const yank: []const Chord = &.{.{ .cp = 'y' }};
pub const replace_with_yank: []const Chord = &.{.{ .cp = 'R' }};
/// helix: the DEFAULT register, not the system clipboard — most terminals
/// refuse the OSC 52 read, so a round trip would never come back
pub const paste_after: []const Chord = &.{.{ .cp = 'p' }};
pub const paste_before: []const Chord = &.{.{ .cp = 'P' }};
pub const switch_case: []const Chord = &.{.{ .cp = '~' }};
pub const to_lowercase: []const Chord = &.{.{ .cp = '`' }};
pub const to_uppercase: []const Chord = &.{.{ .cp = '`', .alt = true }};
pub const join_lines: []const Chord = &.{.{ .cp = 'J' }};
pub const indent: []const Chord = &.{.{ .cp = '>' }};
pub const unindent: []const Chord = &.{.{ .cp = '<' }};
/// helix's format_selections — its neighbour on the keyboard and in the keymap
pub const format: []const Chord = &.{.{ .cp = '=' }};
pub const increment: []const Chord = &.{.{ .cp = 'a', .ctrl = true }};
pub const decrement: []const Chord = &.{.{ .cp = 'x', .ctrl = true }};
pub const undo: []const Chord = &.{.{ .cp = 'u' }};
pub const redo: []const Chord = &.{.{ .cp = 'U' }};
/// helix `toggle_comments`: comment or uncomment every line the selection
/// touches, with `comment_tokens` above choosing the token. Ctrl-c reaches a
/// terminal pane only in NORMAL mode — raw tty forwards it to the program,
/// where it is still SIGINT.
pub const comment_toggle: []const Chord = &.{.{ .cp = 'c', .ctrl = true }};

/// In body normal mode, clear modal residue and run Toggleterm (the same
/// builtin as `SPC w t`). Elsewhere: leave insert mode; abandon a leader path,
/// tag, armed search or the topbar; raw tty mode forwards it to the program.
pub const escape: []const Chord = &.{.{ .cp = Key.escape }};

// ---- insert mode ----

// The three helix aliases: normalized to the base key and re-dispatched, so
// they behave identically to it everywhere downstream.
pub const insert_backspace_alias: []const Chord = &.{.{ .cp = 'h', .ctrl = true }};
pub const insert_enter_alias: []const Chord = &.{.{ .cp = 'j', .ctrl = true }};
pub const insert_delete_alias: []const Chord = &.{.{ .cp = 'd', .ctrl = true }};
/// helix insert-mode kills. Ctrl-w is also the WINDOW prefix in normal/tty —
/// insert mode wins it, which is helix's own arrangement.
pub const delete_word_backward: []const Chord = &.{ .{ .cp = 'w', .ctrl = true }, .{ .cp = Key.backspace, .alt = true } };
pub const delete_word_forward: []const Chord = &.{ .{ .cp = 'd', .alt = true }, .{ .cp = Key.delete, .alt = true } };
pub const kill_to_line_start: []const Chord = &.{.{ .cp = 'u', .ctrl = true }};
pub const kill_to_line_end: []const Chord = &.{.{ .cp = 'k', .ctrl = true }};