import { describe, expect, it } from "vitest";
import { existsSync, readFileSync } from "node:fs";
import { CrystalAssets } from "../src/game/rom/assets";
import { GameWorld, migrateSave } from "../src/game/world/world";
import { generatePartyMon } from "../src/game/party/pokemon";
import { OW } from "../src/game/world/constants";
import {
  defaultOptions,
  type OptionsView,
} from "../src/game/scripts/options";
import { settle } from "./world-driver";

const romPath =
  process.env.CRYSTAL_ROM_PATH ??
  "Pokemon - Crystal Version (UE) (V1.1) [C][!].gbc";
const NEW_BARK_TOWN = "24:4",
  CYNDAQUIL = 155;

describe.skipIf(!existsSync(romPath))("the options screen", () => {
  const assets = () => new CrystalAssets(new Uint8Array(readFileSync(romPath)));
  function fixture() {
    const world = new GameWorld(
      assets(),
      () => new Date("2026-09-25T12:00:00"),
      () => 0x42,
    );
    world.state.party = [
      generatePartyMon(world.assets.pokemon, {
        species: CYNDAQUIL,
        level: 8,
        item: 0,
        otId: world.playerId,
        ot: "CHRIS",
        dvs: 0x9abc,
        caughtData: 0,
      }),
    ];
    world.restore({
      ...world.save(),
      map: NEW_BARK_TOWN,
      x: 13,
      y: 7,
      direction: "down",
      objects: [],
    });
    return world;
  }
  function startMenu(world: GameWorld) {
    const choice = world.dialogue?.choice;
    if (choice?.kind !== "menu") throw new Error("Expected the start menu.");
    return choice;
  }
  function open(world: GameWorld) {
    expect(world.openStartMenu()).toBe(true);
    world.choose(startMenu(world).items.indexOf("OPTION"));
    return view(world);
  }
  function view(world: GameWorld): OptionsView {
    const choice = world.dialogue?.choice;
    if (choice?.kind !== "options")
      throw new Error(`Expected the options, got ${choice?.kind}`);
    return choice.view;
  }
  const values = (world: GameWorld) => view(world).rows.map((row) => row.value);
  function press(
    world: GameWorld,
    ...buttons: ("a" | "b" | "up" | "down" | "left" | "right" | "start")[]
  ) {
    for (const button of buttons) {
      if (button === "a") world.interact();
      else if (button === "b") world.advanceDialogue();
      else if (button === "start") world.choose("start");
      else world.moveCursor(button);
    }
  }
  /** Leave the options and the start menu, committing the draft. */
  function close(world: GameWorld) {
    press(world, "b");
    startMenu(world);
    settle(world, [-1]);
    expect(world.busy).toBe(false);
    expect(world.diagnostic).toBe("");
  }

  it("lists the ROM's options with the default settings", () => {
    const world = fixture();
    const options = open(world);
    expect(options.rows.map((row) => row.label)).toEqual([
      "TEXT SPEED",
      "BATTLE SCENE",
      "BATTLE STYLE",
      "SOUND",
      "PRINT",
      "MENU ACCOUNT",
      "FRAME",
      "CANCEL",
    ]);
    expect(values(world)).toEqual([
      "MID",
      "ON",
      "SHIFT",
      "MONO",
      "NORMAL",
      "ON",
      "TYPE 1",
      "",
    ]);
    expect(options.cursor).toBe(0);
  });

  it("wraps the cursor and cycles each setting both ways", () => {
    const world = fixture();
    open(world);
    press(world, "up");
    expect(view(world).cursor).toBe(7);
    press(world, "down");
    expect(view(world).cursor).toBe(0);
    // Text speed: MID, SLOW, FAST, MID to the right.
    const speeds = [];
    for (let i = 0; i < 3; i++) {
      press(world, "right");
      speeds.push(values(world)[0]);
    }
    expect(speeds).toEqual(["SLOW", "FAST", "MID"]);
    press(world, "left");
    expect(values(world)[0]).toBe("FAST");
    // Battle scene, style and sound toggle with either direction.
    press(world, "down", "right", "down", "left", "down", "right");
    expect(values(world).slice(1, 4)).toEqual(["OFF", "SET", "STEREO"]);
    // Printing: NORMAL, then left to LIGHTER, LIGHTEST and round to DARKEST.
    press(world, "down", "left", "left", "left");
    expect(values(world)[4]).toBe("DARKEST");
    press(world, "down", "right");
    expect(values(world)[5]).toBe("OFF");
    // Frames wrap from 1 to 8.
    press(world, "down", "left");
    expect(values(world)[6]).toBe("TYPE 8");
    press(world, "right", "right");
    expect(values(world)[6]).toBe("TYPE 2");
    // A only acts on CANCEL.
    press(world, "a");
    expect(view(world).cursor).toBe(6);
    press(world, "down", "a");
    startMenu(world);
    settle(world, [-1]);
    expect(world.state.options).toEqual({
      options:
        OW.TEXT_DELAY_FAST |
        (1 << OW.STEREO) |
        (1 << OW.BATTLE_SHIFT) |
        (1 << OW.BATTLE_SCENE),
      textboxFrame: 1,
      printerBrightness: OW.GBPRINTER_DARKEST,
      options2: 0,
    });
  });

  it("leaves with Start and keeps the text speed's high bits only", () => {
    const world = fixture();
    // Bit 3 is cleared by Options_TextSpeed's .Save; bit 4 survives.
    world.state.options.options = 0b0001_1011;
    open(world);
    expect(values(world)[0]).toBe("MID");
    press(world, "right", "start");
    startMenu(world);
    settle(world, [-1]);
    expect(world.state.options.options).toBe(0b0001_0101);
  });

  it("hides the start menu's descriptions without the menu account", () => {
    const world = fixture();
    open(world);
    expect(world.dialogue).toBeDefined();
    press(world, "up", "up", "up", "right", "b");
    expect(startMenu(world).details).toBeUndefined();
    settle(world, [-1]);
    expect(world.openStartMenu()).toBe(true);
    expect(startMenu(world).details).toBeUndefined();
    settle(world, [-1]);
  });

  it("commits with the start menu and saves the options", () => {
    const world = fixture();
    open(world);
    press(world, "down", "down", "right");
    // A save while the menu is open keeps the earlier options.
    expect(world.save().options).toEqual(defaultOptions());
    close(world);
    const save = world.save();
    expect(save.options.options).toBe(OW.TEXT_DELAY_MED | (1 << OW.BATTLE_SHIFT));
    const other = fixture();
    other.restore(save);
    expect(other.state.options).toEqual(save.options);
    const { options: _, ...old } = save;
    expect(migrateSave(old, () => 0)?.options).toEqual(defaultOptions());
    expect(() =>
      other.restore({ ...save, options: { ...save.options, textboxFrame: 8 } }),
    ).toThrow(/Invalid native save/);
  });
});