// @vitest-environment happy-dom
import { describe, expect, it, vi } from "vitest";

import {
  COMMAND_SPECS,
  CommandSet,
  commandSpecs,
  DEFAULT_LEADER,
  canonicalizeKey,
  controlByte,
  defineCommands,
  isBarTypingTarget,
  isTerminalTextarea,
  isTypingTarget,
  keyCaps,
  publishedCommands,
  type Command,
} from "./commands.js";

function key(k: string, init: KeyboardEventInit = {}): KeyboardEvent {
  return new KeyboardEvent("keydown", { key: k, cancelable: true, ...init });
}

function el(html: string): HTMLElement {
  const d = document.createElement("div");
  d.innerHTML = html;
  return d.firstElementChild as HTMLElement;
}

/** Dispatch on a target, so `isTypingTarget` sees something other than null. */
function pressOn(set: CommandSet, target: HTMLElement, k: string, init?: KeyboardEventInit): boolean {
  const e = key(k, init);
  Object.defineProperty(e, "target", { value: target });
  return set.handle(e);
}

describe("command specs", () => {
  it("has a unique id and at least one chord per command", () => {
    const ids = COMMAND_SPECS.map((s) => s.id);
    expect(new Set(ids).size).toBe(ids.length);
    for (const spec of COMMAND_SPECS) {
      expect(spec.keys.length).toBeGreaterThan(0);
      expect(spec.label.length).toBeGreaterThan(0);
    }
  });

  it("binds each chord once within a scope", () => {
    const seen = new Set<string>();
    for (const spec of COMMAND_SPECS) {
      for (const k of spec.keys) {
        const slot = `${spec.scope}:${k}`;
        expect(seen.has(slot)).toBe(false);
        seen.add(slot);
      }
    }
  });

  it("rejects a handler for an id that isn't in the registry", () => {
    expect(() => defineCommands({ "nope.missing": () => {} })).toThrow(/unknown command id/);
  });

  it("carries every spec field onto the defined command", () => {
    const [cmd] = defineCommands({ "spawn.open": () => {} });
    expect(cmd).toMatchObject({ id: "spawn.open", keys: ["n"], scope: "global" });
  });
});

describe("canonicalizeKey", () => {
  it("spells keys the way the TUI's InputKey::canonical does", () => {
    expect(canonicalizeKey(key("n"))).toBe("n");
    expect(canonicalizeKey(key("N", { shiftKey: true }))).toBe("N");
    expect(canonicalizeKey(key("?", { shiftKey: true }))).toBe("?");
    expect(canonicalizeKey(key("a", { ctrlKey: true }))).toBe("ctrl-a");
    expect(canonicalizeKey(key("Escape"))).toBe("esc");
    expect(canonicalizeKey(key("Enter"))).toBe("enter");
    expect(canonicalizeKey(key("Tab"))).toBe("tab");
    expect(canonicalizeKey(key("Tab", { shiftKey: true }))).toBe("backtab");
    expect(canonicalizeKey(key("ArrowDown"))).toBe("down");
  });

  it("folds a modified letter to lower case with an explicit shift-", () => {
    expect(canonicalizeKey(key("H", { ctrlKey: true, shiftKey: true }))).toBe("ctrl-shift-h");
    expect(canonicalizeKey(key("h", { ctrlKey: true, shiftKey: true }))).toBe("ctrl-shift-h");
  });

  it("has no canonical form for a modifier pressed alone", () => {
    expect(canonicalizeKey(key("Control", { ctrlKey: true }))).toBeNull();
    expect(canonicalizeKey(key("Shift", { shiftKey: true }))).toBeNull();
  });
});

describe("keyCaps", () => {
  it("renders one cap per modifier and key", () => {
    expect(keyCaps("ctrl-shift-h")).toEqual(["Ctrl", "Shift", "H"]);
    expect(keyCaps("enter")).toEqual(["Enter"]);
    expect(keyCaps("j")).toEqual(["j"]);
    expect(keyCaps("N")).toEqual(["N"]);
    expect(keyCaps("?")).toEqual(["?"]);
    expect(keyCaps("ctrl-a ctrl-k")).toEqual(["Ctrl", "A", "then", "Ctrl", "K"]);
  });
});

describe("CommandSet", () => {
  it("runs the command bound to a chord, and swallows the browser default", () => {
    const run = vi.fn();
    const set = new CommandSet(defineCommands({ "spawn.open": run }));
    const e = key("n");
    expect(set.handle(e)).toBe(true);
    expect(run).toHaveBeenCalledTimes(1);
    expect(e.defaultPrevented).toBe(true);
  });

  it("leaves an unbound key alone", () => {
    const set = new CommandSet(defineCommands({ "spawn.open": vi.fn() }));
    const e = key("q");
    expect(set.handle(e)).toBe(false);
    expect(e.defaultPrevented).toBe(false);
  });

  it("treats a modified key as a different binding", () => {
    const run = vi.fn();
    const set = new CommandSet(defineCommands({ "spawn.open": run }));
    expect(set.handle(key("n", { ctrlKey: true }))).toBe(false);
    expect(set.handle(key("n", { metaKey: true }))).toBe(false);
    expect(run).not.toHaveBeenCalled();
  });

  it("runs every alias of a command", () => {
    const run = vi.fn();
    const set = new CommandSet(defineCommands({ "list.next": run }));
    set.handle(key("j"));
    set.handle(key("ArrowDown"));
    expect(run).toHaveBeenCalledTimes(2);
  });

  it("keeps plain keys deaf inside a form field, and leader chords live from the pane", () => {
    const plain = vi.fn();
    const chorded = vi.fn();
    const set = new CommandSet(
      defineCommands({ "spawn.open": plain, "focus.toggle": chorded }, DEFAULT_LEADER),
      { leader: DEFAULT_LEADER },
    );
    const input = el("<input>");
    expect(pressOn(set, input, "n")).toBe(false);
    expect(plain).not.toHaveBeenCalled();
    // focus.toggle hangs off the leader (#166): a plain, unmodified Escape is
    // left for the pane's shell/app instead.
    const terminal = el('<textarea class="xterm-helper-textarea"></textarea>');
    pressOn(set, terminal, "a", { ctrlKey: true });
    expect(pressOn(set, terminal, "h")).toBe(true);
    expect(chorded).toHaveBeenCalledTimes(1);
  });

  it("leaves a plain Escape for the pane instead of binding it", () => {
    const set = new CommandSet(defineCommands({ "spawn.open": vi.fn() }));
    const textarea = el('<textarea class="xterm-helper-textarea"></textarea>');
    expect(pressOn(set, textarea, "Escape")).toBe(false);
  });
});

describe("the leader", () => {
  it("defaults to the TUI's ctrl-a", () => {
    expect(DEFAULT_LEADER).toBe("ctrl-a");
  });

  // #159: the leader is the operator's, served on `/api/info`. Every chord
  // behind it is built from it, so a rebound leader carries its escape hatches
  // with it instead of leaving them on a stale ctrl-a.
  it("builds the chords behind it from the configured leader", () => {
    const byId = new Map(commandSpecs("ctrl-b").map((s) => [s.id, s]));
    expect(byId.get("pane.literalCtrlK")?.keys).toEqual(["ctrl-b ctrl-k"]);
    expect(byId.get("pane.literalLeader")?.keys).toEqual(["ctrl-b ctrl-b"]);
    expect(byId.get("focus.toggle")?.keys).toEqual(["ctrl-b h"]);
    // Commands that do not hang off the leader are untouched.
    expect(byId.get("bar.open")?.keys).toEqual(["ctrl-k"]);
  });

  it("dispatches a configured leader's chord and not the default's", () => {
    const literalCtrlK = vi.fn();
    const set = new CommandSet(defineCommands({ "pane.literalCtrlK": literalCtrlK }, "ctrl-b"), {
      leader: "ctrl-b",
    });
    set.handle(key("b", { ctrlKey: true }));
    expect(set.handle(key("k", { ctrlKey: true }))).toBe(true);
    expect(literalCtrlK).toHaveBeenCalledTimes(1);

    // The old leader is an ordinary key again: it holds nothing, and the chord
    // that used to follow it runs nothing.
    set.handle(key("a", { ctrlKey: true }));
    set.handle(key("k", { ctrlKey: true }));
    expect(literalCtrlK).toHaveBeenCalledTimes(1);
  });

  it("sends the configured leader's own byte for the doubled chord", () => {
    expect(controlByte("ctrl-b")).toBe("\x02");
  });

  it("holds the leader as a partial chord instead of selecting the page", () => {
    const set = new CommandSet(defineCommands({ "spawn.open": vi.fn() }), {
      leader: DEFAULT_LEADER,
    });
    const e = key("a", { ctrlKey: true });
    expect(set.handle(e)).toBe(true);
    expect(e.defaultPrevented).toBe(true);
  });

  it("swallows the key after the leader rather than running its plain binding", () => {
    const run = vi.fn();
    const set = new CommandSet(defineCommands({ "spawn.open": run }), {
      leader: DEFAULT_LEADER,
    });
    set.handle(key("a", { ctrlKey: true }));
    expect(set.handle(key("n"))).toBe(true);
    expect(run).not.toHaveBeenCalled();
    // The next key is an ordinary one again.
    set.handle(key("n"));
    expect(run).toHaveBeenCalledTimes(1);
  });

  it("forgets a held leader once the chord timeout passes", () => {
    const run = vi.fn();
    let now = 0;
    const set = new CommandSet(defineCommands({ "spawn.open": run }), {
      leader: DEFAULT_LEADER,
      chordTimeoutMs: 1000,
      now: () => now,
    });
    set.handle(key("a", { ctrlKey: true }));
    now = 1500;
    set.handle(key("n"));
    expect(run).toHaveBeenCalledTimes(1);
  });

  it("leaves select-all alone in a real form field", () => {
    const set = new CommandSet(defineCommands({ "spawn.open": vi.fn() }), {
      leader: DEFAULT_LEADER,
    });
    const input = el("<input>");
    const e = key("a", { ctrlKey: true });
    Object.defineProperty(e, "target", { value: input });
    expect(set.handle(e)).toBe(false);
    expect(e.defaultPrevented).toBe(false);
  });
});

describe("publishing", () => {
  it("lists a constructed set's commands, replacing an id rather than doubling it", () => {
    new CommandSet(defineCommands({ "list.kill": () => {} }));
    new CommandSet(defineCommands({ "list.kill": () => {} }));
    const ids = publishedCommands().map((c) => c.id);
    expect(ids.filter((id) => id === "list.kill")).toEqual(["list.kill"]);
  });

  it("keeps published commands in registry order", () => {
    const order = COMMAND_SPECS.map((s) => s.id);
    const ids = publishedCommands().map((c) => c.id);
    expect(ids).toEqual(order.filter((id) => ids.includes(id)));
  });
});

describe("isTypingTarget", () => {
  it("is true for form fields and editable nodes, false otherwise", () => {
    expect(isTypingTarget(el("<input>"))).toBe(true);
    expect(isTypingTarget(el("<textarea></textarea>"))).toBe(true);
    expect(isTypingTarget(el("<select></select>"))).toBe(true);
    expect(isTypingTarget(el('<div contenteditable="true"></div>'))).toBe(true);
    expect(isTypingTarget(el("<button></button>"))).toBe(false);
    expect(isTypingTarget(null)).toBe(false);
  });
});

describe("isTerminalTextarea", () => {
  it("recognises xterm's offscreen textarea, and nothing else", () => {
    expect(isTerminalTextarea(el('<textarea class="xterm-helper-textarea"></textarea>'))).toBe(true);
    expect(isTerminalTextarea(el("<textarea></textarea>"))).toBe(false);
    expect(isTerminalTextarea(el("<input>"))).toBe(false);
    expect(isTerminalTextarea(null)).toBe(false);
  });
});

describe("isBarTypingTarget", () => {
  it("holds the bar's keys out of real form fields", () => {
    expect(isBarTypingTarget(el("<input>"))).toBe(true);
    expect(isBarTypingTarget(el("<textarea></textarea>"))).toBe(true);
  });

  it("does not count the terminal's textarea, so ctrl-k reaches the bar there", () => {
    expect(isBarTypingTarget(el('<textarea class="xterm-helper-textarea"></textarea>'))).toBe(false);
    expect(isBarTypingTarget(el("<button></button>"))).toBe(false);
    expect(isBarTypingTarget(null)).toBe(false);
  });
});

describe("ctrl-k over a focused pane (#152)", () => {
  const terminal = () => el('<textarea class="xterm-helper-textarea"></textarea>');

  /** The global listener's routing: the bar's set only sees a key that is not
   *  aimed at a real form field. */
  function route(set: CommandSet, target: HTMLElement, k: string, init?: KeyboardEventInit) {
    if (isBarTypingTarget(target)) return false;
    return pressOn(set, target, k, init);
  }

  it("opens the bar when the terminal has the keyboard", () => {
    const open = vi.fn();
    const set = new CommandSet(defineCommands({ "bar.open": open }));
    expect(route(set, terminal(), "k", { ctrlKey: true })).toBe(true);
    expect(open).toHaveBeenCalledTimes(1);
  });

  it("leaves the spawn form's inputs their own Ctrl-K", () => {
    const open = vi.fn();
    const set = new CommandSet(defineCommands({ "bar.open": open }));
    expect(route(set, el("<input>"), "k", { ctrlKey: true })).toBe(false);
    expect(open).not.toHaveBeenCalled();
  });

  it("sends the literal 0x0B after the leader, without opening the bar", () => {
    const open = vi.fn();
    const literal = vi.fn();
    const bar = new CommandSet(defineCommands({ "bar.open": open }));
    const set = new CommandSet(defineCommands({ "pane.literalCtrlK": literal }), {
      leader: DEFAULT_LEADER,
    });
    const target = terminal();
    expect(pressOn(set, target, "a", { ctrlKey: true })).toBe(true);
    const e = key("k", { ctrlKey: true });
    Object.defineProperty(e, "target", { value: target });
    expect(set.handle(e)).toBe(true);
    expect(literal).toHaveBeenCalledTimes(1);
    // The leader's set consumed the key, so the bar's set never sees it.
    expect(open).not.toHaveBeenCalled();
    expect(bar.handle(e)).toBe(true); // sanity: it would have opened otherwise
    expect(open).toHaveBeenCalledTimes(1);
  });

  it("binds the escape hatch behind the default leader", () => {
    const spec = COMMAND_SPECS.find((s) => s.id === "pane.literalCtrlK");
    expect(spec?.keys).toEqual([`${DEFAULT_LEADER} ctrl-k`]);
  });
});

describe("leader pressed twice (#158)", () => {
  it("sends one literal leader byte and clears the pending chord", () => {
    const literal = vi.fn();
    const run = vi.fn();
    const set = new CommandSet(
      defineCommands({ "pane.literalLeader": literal, "spawn.open": run }),
      { leader: DEFAULT_LEADER },
    );
    const target = el('<textarea class="xterm-helper-textarea"></textarea>');
    expect(pressOn(set, target, "a", { ctrlKey: true })).toBe(true);
    expect(pressOn(set, target, "a", { ctrlKey: true })).toBe(true);
    expect(literal).toHaveBeenCalledTimes(1);
    // The chord is cleared, not still held: the next key is ordinary again.
    expect(set.handle(key("n"))).toBe(true);
    expect(run).toHaveBeenCalledTimes(1);
  });

  it("binds the escape hatch behind the default leader", () => {
    const spec = COMMAND_SPECS.find((s) => s.id === "pane.literalLeader");
    expect(spec?.keys).toEqual([`${DEFAULT_LEADER} ${DEFAULT_LEADER}`]);
  });

  // Not just the default: the chord is resolved from whatever leader this
  // set was constructed with, so a rebound leader carries the escape hatch
  // with it — the same proof #156 wrote for the TUI. The web has no config
  // for this yet (#159), but the mechanism must not be hardcoded to ctrl-a.
  it("follows a rebound leader, not just the default", () => {
    const literal = vi.fn();
    const rebound: Command = {
      id: "pane.literalLeader",
      label: "Send a literal leader key to the pane",
      group: "Pane",
      scope: "global",
      keys: ["ctrl-b ctrl-b"],
      run: literal,
    };
    const set = new CommandSet([rebound], { leader: "ctrl-b" });
    const target = el('<textarea class="xterm-helper-textarea"></textarea>');
    expect(pressOn(set, target, "b", { ctrlKey: true })).toBe(true);
    expect(pressOn(set, target, "b", { ctrlKey: true })).toBe(true);
    expect(literal).toHaveBeenCalledTimes(1);
    // The old leader no longer does anything special.
    expect(pressOn(set, target, "a", { ctrlKey: true })).toBe(false);
  });
});

describe("controlByte", () => {
  it("computes the raw control byte from a plain ctrl chord", () => {
    expect(controlByte("ctrl-a")).toBe("\x01");
    expect(controlByte("ctrl-k")).toBe("\x0b");
  });

  it("rejects anything that isn't a single plain ctrl chord", () => {
    expect(() => controlByte("ctrl-shift-a")).toThrow();
    expect(() => controlByte("a")).toThrow();
    expect(() => controlByte("ctrl-a ctrl-a")).toThrow();
  });
});