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 { emptyScriptState } from "../src/game/scripts/interpreter";
import { generatePartyMon } from "../src/game/party/pokemon";
import type { Direction } from "../src/game/world/types";
import { settle, findPath } from "./world-driver";

const romPath =
  process.env.CRYSTAL_ROM_PATH ?? "Pokemon - Crystal Version (UE) (V1.1) [C][!].gbc";

// Item IDs read from constants/item_constants.asm, not reference-checked
// here (only ROM/RAM addresses in profile.ts are).
const SUN_STONE = 169,
  EVERSTONE = 112,
  BERRY = 173,
  GOLD_BERRY = 174;
// CATERPIE and WEEDLE (constants/pokemon_constants.asm): ContestMons'
// first two entries, each 20%.
const CATERPIE = 10,
  WEEDLE = 13;

const ROUTE35_GATE = "10:15",
  ROUTE36_GATE = "10:17",
  NATIONAL_PARK = "3:15",
  CONTEST_PARK = "3:16";
// Date#getDay() matches the ROM's SUNDAY..SATURDAY (0-6) directly, as the
// rest of the native clock already assumes (world.ts's weekday math).
const CONTEST_DAY = "2026-09-22T12:00:00"; // Tuesday
const OFF_DAY = "2026-09-25T12:00:00"; // Friday
// A COLL_LONG_GRASS patch reachable from the Route 36 gate's warp-in
// point (33, 18); the Route 35 gate's own (10, 47) lands in a separate,
// grass-less walkable region of this map.
const GRASS = { x: 31, y: 17 };
const GRASS2 = { x: 30, y: 17 };

function fixture(options: { day?: string; party?: number[] } = {}) {
  const assets = new CrystalAssets(new Uint8Array(readFileSync(romPath)));
  let now = new Date(options.day ?? CONTEST_DAY);
  let seed = 7;
  const forced: number[] = [];
  const random = () => {
    if (forced.length) return forced.shift()!;
    seed = (seed * 1103515245 + 12345) >>> 0;
    return (seed >>> 16) & 255;
  };
  const world = new GameWorld(assets, () => now, random);
  const species = options.party ?? [155]; // Cyndaquil: strong enough that nothing faints.
  world.state.party = species.map((sp) =>
    generatePartyMon(assets.pokemon, {
      species: sp,
      level: 60,
      item: 0,
      otId: world.playerId,
      ot: "CHRIS",
      dvs: 0xffff,
      caughtData: 0,
    }),
  );
  world.state.money = 3000;
  return {
    world,
    forced,
    advance: (ms: number) => {
      now = new Date(now.getTime() + ms);
    },
  };
}

/** Teleport straight into a gate or the park, bypassing Route 35/36/37
 * (opened separately; see the task brief). */
function enterAt(
  world: GameWorld,
  map: string,
  x: number,
  y: number,
  direction: Direction = "down",
) {
  world.restore({ ...world.save(), map, x, y, direction, objects: [] });
}

/** Walk to a tile, stopping early if a step starts a battle (findPath's
 * BFS keeps walking around the contest's roaming NPCs). */
function walkToOrBattle(world: GameWorld, x: number, y: number) {
  for (const direction of findPath(world, x, y)) {
    if (world.battle) return;
    if (!world.move(direction)) throw new Error(`Blocked moving ${direction}.`);
    for (let tick = 0; tick < 40 && world.busy && !world.battle; tick++)
      world.tick();
    if (world.battle) return;
  }
}

/** Drive a Bug-Catching Contest battle: PARKBALL× on every action prompt,
 * as the contest's own battle menu requires. */
function driveContestBattle(world: GameWorld, switchIn = true) {
  for (let tick = 0; tick < 20_000; tick++) {
    const view = world.battle;
    if (!view) return;
    const prompt = view.prompt;
    if (prompt?.kind === "action")
      world.battleAction({ action: "item", item: 0, slot: 0 });
    else if (prompt?.kind === "yesno") world.battleChoose(1);
    else if (prompt?.kind === "contestswitch")
      world.battleChoose(switchIn ? 1 : 0);
    else if (prompt?.kind === "name") world.battleName("");
    else if (prompt?.kind === "stats" || view.message?.prompt) world.interact();
    else world.tick();
  }
  throw new Error("The contest battle did not settle.");
}

/** Registers at the Route 35 gate (a one-Pokémon party skips the "leave
 * the rest behind" question) and lands in the contest map. */
function register(world: GameWorld) {
  enterAt(world, ROUTE35_GATE, 2, 2, "up");
  world.interact();
  settle(world);
  expect(world.notice, world.diagnostic).toBe("");
  expect(world.mapId).toBe(CONTEST_PARK);
}

describe.skipIf(!existsSync(romPath))("the Bug-Catching Contest", () => {
  it("the gate's officer offers the contest on Tuesday/Thursday/Saturday", () => {
    const { world } = fixture({ day: CONTEST_DAY });
    register(world);
    expect(world.state.bugContest).toEqual({ parkBalls: 20, mon: null });
    expect(world.state.bugContestEnd).toBeGreaterThan(Date.parse(CONTEST_DAY));
    expect(world.state.flags.has(17)).toBe(true); // ENGINE_BUG_CONTEST_TIMER
    expect(world.x).toBe(10);
    expect(world.y).toBe(47);
  });

  it("an off day only explains the contest, without starting one", () => {
    const { world } = fixture({ day: OFF_DAY });
    enterAt(world, ROUTE35_GATE, 0, 2, "down");
    world.interact();
    const shown = settle(world);
    expect(world.notice, world.diagnostic).toBe("");
    expect(shown.join("\n")).toMatch(/PARK/);
    expect(world.state.bugContest).toBeUndefined();
    expect(world.mapId).toBe(ROUTE35_GATE);
  });

  it("leaves the rest of the party with the contest helper when it has more than one Pokémon", () => {
    const { world } = fixture({ party: [155, 16] }); // Cyndaquil, Pidgey
    enterAt(world, ROUTE35_GATE, 2, 2, "up");
    world.interact();
    settle(world); // "Would you like to try?" / "use the first Pokémon?" / promptbuttons
    expect(world.notice, world.diagnostic).toBe("");
    expect(world.state.party).toHaveLength(1);
    expect(world.state.party[0].species).toBe(155);
    expect(world.mapId).toBe(CONTEST_PARK);
  });

  it("refuses to register with a fainted or an Egg first Pokémon", () => {
    {
      const { world } = fixture({ party: [155, 16] });
      world.state.party[0].hp = 0;
      enterAt(world, ROUTE35_GATE, 2, 2, "up");
      world.interact();
      const shown = settle(world);
      expect(world.notice, world.diagnostic).toBe("");
      expect(shown.join("\n")).toMatch(/can't battle/);
      expect(world.state.bugContest).toBeUndefined();
    }
    {
      const { world } = fixture({ party: [155, 16] });
      world.state.party[0].egg = true;
      enterAt(world, ROUTE35_GATE, 2, 2, "up");
      world.interact();
      const shown = settle(world);
      expect(world.notice, world.diagnostic).toBe("");
      expect(shown.join("\n")).toMatch(/EGG/);
      expect(world.state.bugContest).toBeUndefined();
    }
  });

  it("catches a bug, catches a second and swaps, then quits early for judging and a prize", () => {
    const { world, forced } = fixture({ day: CONTEST_DAY });
    // The Route 36 gate's own registration lands at (33, 18), which (unlike
    // the Route 35 gate's (10, 47)) can reach this map's grass.
    enterAt(world, ROUTE36_GATE, 0, 4, "up");
    world.interact();
    settle(world);
    expect(world.notice, world.diagnostic).toBe("");
    expect(world.mapId).toBe(CONTEST_PARK);
    // SetUpFiveStepWildEncounterCooldown: walk off the five-step cooldown
    // from entering the map on safe (non-grass) ground before approaching it.
    walkToOrBattle(world, 28, 18);
    expect(world.battle).toBeUndefined();
    // Force the first encounter (long grass: 40% of 255) onto Caterpie
    // (ContestMons' first 20% entry) at its minimum level.
    forced.push(0, 0, 0);
    walkToOrBattle(world, GRASS.x, GRASS.y);
    expect(world.battle).toBeDefined();
    driveContestBattle(world);
    expect(world.notice, world.diagnostic).toBe("");
    expect(world.state.bugContest?.mon?.species).toBe(CATERPIE);
    expect(world.state.bugContest?.parkBalls).toBeLessThan(20);
    const ballsAfterFirst = world.state.bugContest!.parkBalls;

    // A second catch (the next ContestMons entry, Weedle) offers a swap.
    forced.push(0, 50, 0);
    walkToOrBattle(world, GRASS2.x, GRASS2.y);
    if (!world.battle) walkToOrBattle(world, GRASS.x, GRASS.y);
    expect(world.battle).toBeDefined();
    driveContestBattle(world, true);
    expect(world.notice, world.diagnostic).toBe("");
    expect(world.state.bugContest?.mon?.species).toBe(WEEDLE);
    expect(world.state.bugContest!.parkBalls).toBeLessThan(ballsAfterFirst);

    // QUIT replaces SAVE in the start menu, and PACK is not offered.
    world.openStartMenu();
    const menu = world.dialogue!.choice as { kind: "menu"; items: string[] };
    expect(menu.kind).toBe("menu");
    expect(menu.items.some((label) => /PACK/.test(label))).toBe(false);
    const quitIndex = menu.items.findIndex((label) => /QUIT/.test(label));
    expect(quitIndex).toBeGreaterThanOrEqual(0);
    world.choose(quitIndex);
    expect(world.dialogue?.choice?.kind).toBe("yesno");
    world.choose(1); // "Do you want to finish now?"
    // BugContestResultsScript: the ready-to-judge text, third/second/first
    // place announcements, the player's own prize (or consolation Berry),
    // the returned party (none left behind here) and the nickname offer.
    const shown = settle(world, [1, ""]);
    expect(world.notice, world.diagnostic).toBe("");
    expect(shown.join("\n")).toMatch(/Weedle|WEEDLE/i);
    expect(world.state.bugContest).toBeUndefined();
    expect(world.state.bugContestEnd).toBeUndefined();
    expect(world.state.flags.has(17)).toBe(false);
    expect(world.mapId).toBe(ROUTE36_GATE);
    // The judged Weedle joined the party (which had room) with the
    // National Park as its caught location.
    const caught = world.state.party.at(-1)!;
    expect(caught.species).toBe(WEEDLE);
    expect(caught.caughtData & 0x7f).toBe(0x13); // LANDMARK_NATIONAL_PARK
  });

  it("ends the contest and prints the judging when the twenty minutes run out", () => {
    const { world, advance } = fixture({ day: CONTEST_DAY });
    register(world);
    advance(21 * 60_000);
    const shown = settle(world);
    expect(world.notice, world.diagnostic).toBe("");
    expect(shown.join("\n")).toMatch(/time|Time/);
    expect(world.state.bugContest).toBeUndefined();
    expect(world.mapId).toBe(ROUTE36_GATE);
  });

  it("awards first place and the Sun Stone to an outstanding catch", () => {
    const { world } = fixture({ day: CONTEST_DAY });
    register(world);
    // A maximum-level, maximum-stat catch outscores every AI contestant.
    world.state.bugContest = {
      parkBalls: 15,
      mon: generatePartyMon(world.assets.pokemon, {
        species: 127, // Pinsir: a real ContestMons rare entry, high stats.
        level: 100,
        item: 0,
        otId: world.playerId,
        ot: "CHRIS",
        dvs: 0xffff,
        caughtData: 0,
      }),
    };
    const before = world.state.bag.items.find((slot) => slot.item === SUN_STONE)?.quantity ?? 0;
    world.openStartMenu();
    const menu = world.dialogue!.choice as { kind: "menu"; items: string[] };
    world.choose(menu.items.findIndex((label) => /QUIT/.test(label)));
    world.choose(1);
    const shown = settle(world, [1, ""]);
    expect(world.notice, world.diagnostic).toBe("");
    expect(shown.join("\n")).toMatch(/winner/i);
    const after = world.state.bag.items.find((slot) => slot.item === SUN_STONE)?.quantity ?? 0;
    expect(after).toBe(before + 1);
  });

  it("boxes the catch when the party is full, with the National Park landmark", () => {
    const { world } = fixture({ day: CONTEST_DAY, party: [155, 16, 19, 1, 4, 7] });
    // Registering with more than one Pokémon leaves the other five with
    // the helper (ContestDropOffMons); ContestReturnMons restores them
    // during judging, which is where the party is actually full again.
    register(world);
    expect(world.state.party).toHaveLength(1);
    expect(world.state.contestLeftParty).toHaveLength(5);
    world.state.bugContest = {
      parkBalls: 10,
      mon: generatePartyMon(world.assets.pokemon, {
        species: CATERPIE,
        level: 7,
        item: 0,
        otId: world.playerId,
        ot: "CHRIS",
        dvs: 0,
        caughtData: 0,
      }),
    };
    world.openStartMenu();
    const menu = world.dialogue!.choice as { kind: "menu"; items: string[] };
    world.choose(menu.items.findIndex((label) => /QUIT/.test(label)));
    world.choose(1);
    const shown = settle(world, [1, ""]);
    expect(world.notice, world.diagnostic).toBe("");
    expect(world.state.party).toHaveLength(6); // unchanged; went to the box
    const box = world.state.storage.boxes[world.state.storage.current];
    expect(box[0]?.species).toBe(CATERPIE);
    expect(box[0]?.caughtData & 0x7f).toBe(0x13);
    expect(shown.join("\n")).toMatch(/PC|BOX/i);
  });

  it("saves and restores mid-contest, keeping the Park Balls, caught mon and deadline", () => {
    const { world } = fixture({ day: CONTEST_DAY });
    register(world);
    world.state.bugContest = {
      parkBalls: 12,
      mon: generatePartyMon(world.assets.pokemon, {
        species: WEEDLE,
        level: 9,
        item: 0,
        otId: world.playerId,
        ot: "CHRIS",
        dvs: 0x1234,
        caughtData: 0,
      }),
    };
    const saved = world.save();
    expect(saved.bugContest).toEqual({ parkBalls: 12, mon: world.state.bugContest.mon });
    expect(saved.bugContestEnd).toBe(world.state.bugContestEnd);

    const assets2 = new CrystalAssets(new Uint8Array(readFileSync(romPath)));
    const reloaded = new GameWorld(assets2, () => new Date(CONTEST_DAY), () => 0);
    reloaded.restore(saved);
    expect(reloaded.notice, reloaded.diagnostic).toBe("");
    expect(reloaded.state.bugContest).toEqual(world.state.bugContest);
    expect(reloaded.state.bugContestEnd).toBe(world.state.bugContestEnd);
    // The deadline survives the reload and still ends the contest on time.
    const laterSave = { ...reloaded.save() };
    const assets3 = new CrystalAssets(new Uint8Array(readFileSync(romPath)));
    let later = new Date(Date.parse(CONTEST_DAY) + 21 * 60_000);
    const reloaded2 = new GameWorld(assets3, () => later, () => 0);
    reloaded2.restore(laterSave);
    settle(reloaded2, [1, ""]); // accept the judged Weedle's nickname offer
    expect(reloaded2.notice, reloaded2.diagnostic).toBe("");
    expect(reloaded2.state.bugContest).toBeUndefined();
  });

  it("migrates an older save with no contest fields into no contest running", () => {
    const { world } = fixture();
    const save = world.save() as Record<string, unknown>;
    delete save.bugContest;
    delete save.bugContestEnd;
    const migrated = migrateSave(save, () => 1);
    expect(migrated).toBeDefined();
    expect(migrated!.bugContest).toBeUndefined();
    expect(migrated!.bugContestEnd).toBeUndefined();
    world.restore(migrated);
    expect(world.notice, world.diagnostic).toBe("");
    expect(world.state.bugContest).toBeUndefined();
  });

  it("the National Park's own NPCs and items work outside the contest", () => {
    const { world } = fixture({ day: OFF_DAY });
    enterAt(world, NATIONAL_PARK, 27, 41, "up"); // facing Teacher1 at (27,40)
    world.interact();
    const shown = settle(world);
    expect(world.notice, world.diagnostic).toBe("");
    expect(shown.join("\n")).toMatch(/QUICK CLAW/);
    const item = world.assets.pokemon.itemName(73); // QUICK_CLAW
    expect(world.state.bag.items.some((slot) => world.assets.pokemon.itemName(slot.item) === item)).toBe(true);
  });
});