import { describe, expect, it } from "vitest";
import { existsSync, readFileSync } from "node:fs";
import { CrystalAssets } from "../src/game/rom/assets";
import { textTiles } from "../src/game/rom/font";
import {
  ENGINE_FLAGS,
  SAVE_BLOCK,
  SRAM,
  SYMBOLS,
} from "../src/game/rom/profile";
import { TRAINER_NAME_PATTERN, NICKNAME_PATTERN } from "../src/game/party/pokemon";
import { validStorage, emptyStorage, type BoxMon } from "../src/game/party/storage";
import {
  CartridgeSaveError,
  LAYOUT,
  SAV,
  convertCartridgeSave,
  isCartridgeSaveSize,
} from "../src/game/world/cartridge-save";
import { checkCountdown, rtcDay } from "../src/game/world/day-timers";
import { GameWorld, type NativeSave } from "../src/game/world/world";

const romPath =
  process.env.CRYSTAL_ROM_PATH ??
  "Pokemon - Crystal Version (UE) (V1.1) [C][!].gbc";
const symbolsPath = ".reference/pokecrystal11.sym";
const saves = "debug-saves/Pokémon - Crystal Version";
const cartridgePath = `${saves}/Pokémon - Crystal Version/Pokémon - Crystal Version.sav`;
const virtualConsolePath = `${saves}/Pokémon - Crystal Version [VC]/sav.dat`;

describe("cartridge save names and sizes", () => {
  it("accepts the sizes of a 32 KiB save and its emulator footers only", () => {
    for (const size of [0x8000, 0x8000 + 16, 0x8000 + 44, 0x8000 + 48])
      expect(isCartridgeSaveSize(size)).toBe(true);
    for (const size of [0, 0x2000, 0x8000 - 1, 0x8000 + 1, 0x10000])
      expect(isCartridgeSaveSize(size)).toBe(false);
  });

  it("keeps <PK> and <MN> as one character of a name and one tile", () => {
    expect(TRAINER_NAME_PATTERN.test("Mattiaᴾᴷ")).toBe(true);
    expect(TRAINER_NAME_PATTERN.test("MATTIAᴾᴷ")).toBe(true);
    expect(TRAINER_NAME_PATTERN.test("MATTIAᴾᴷᴹᴺ")).toBe(false);
    expect(TRAINER_NAME_PATTERN.test("ᴾ")).toBe(false);
    expect(NICKNAME_PATTERN.test("ᴾᴷᴹᴺ×(♀)")).toBe(true);
    expect(textTiles("Aᴾᴷᴹᴺ")).toEqual([0x80, 0xe1, 0xe2]);
  });

  it("stores an Egg in a box with its egg mark", () => {
    const egg = {
      species: 175,
      item: 0,
      moves: [1, 0, 0, 0],
      otId: 1,
      ot: "KRIS",
      nickname: "EGG",
      exp: 125,
      statExp: [0, 0, 0, 0, 0],
      dvs: 0,
      pp: [35, 0, 0, 0],
      happiness: 10,
      pokerus: 0,
      caughtData: 0,
      level: 5,
      egg: true,
    } as BoxMon;
    const storage = emptyStorage();
    storage.boxes[0].push(egg);
    expect(validStorage(storage)).toBe(true);
    storage.boxes[0][0] = { ...egg, egg: false as never };
    expect(validStorage(storage)).toBe(false);
  });
});

describe.skipIf(!existsSync(symbolsPath))("cartridge save layout", () => {
  const symbols = new Map<string, [number, number]>();
  if (existsSync(symbolsPath))
    for (const line of readFileSync(symbolsPath, "utf8").split("\n")) {
      const match = /^([0-9a-f]{2}):([0-9a-f]{4}) (\S+)$/.exec(line);
      if (match)
        symbols.set(match[3], [parseInt(match[1], 16), parseInt(match[2], 16)]);
    }
  const at = (label: string) => {
    const symbol = symbols.get(label);
    if (!symbol) throw new Error(`No symbol ${label}`);
    return symbol[1];
  };
  const offset = (field: string, struct: string) => at(field) - at(struct);

  it("matches the struct layouts of the pinned build", () => {
    expect(offset("wPartyMon1BoxEnd", "wPartyMon1")).toBe(LAYOUT.boxMon);
    expect(offset("wPartyMon2", "wPartyMon1")).toBe(LAYOUT.partyMon);
    for (const [field, value] of [
      ["Item", 1],
      ["Moves", 2],
      ["ID", 6],
      ["Exp", 8],
      ["HPExp", 11],
      ["DVs", 21],
      ["PP", 23],
      ["Happiness", 27],
      ["PokerusStatus", 28],
      ["CaughtData", 29],
      ["Level", 31],
      ["Status", 32],
      ["HP", 34],
      ["MaxHP", 36],
      ["SpclDef", 46],
    ] as const)
      expect(offset(`wPartyMon1${field}`, "wPartyMon1"), field).toBe(value);
    expect(offset("sBox1Mons", "sBox1")).toBe(1 + SAV.MONS_PER_BOX + 1);
    expect(offset("sBox1MonOTs", "sBox1")).toBe(
      1 + SAV.MONS_PER_BOX + 1 + SAV.MONS_PER_BOX * LAYOUT.boxMon,
    );
    expect(offset("sBox1MonNicknames", "sBox1MonOTs")).toBe(
      SAV.MONS_PER_BOX * SAV.NAME_LENGTH,
    );
    expect(offset("sBox2", "sBox1")).toBe(LAYOUT.box);
    expect(offset("sHallOfFame2", "sHallOfFame1")).toBe(LAYOUT.hallOfFame);
    expect(offset("sHallOfFame1Mon1", "sHallOfFame1")).toBe(1);
    expect(offset("sHallOfFame1Mon2", "sHallOfFame1Mon1")).toBe(
      LAYOUT.hallOfFameMon,
    );
    expect(offset("sHallOfFame1Mon1ID", "sHallOfFame1Mon1")).toBe(1);
    expect(offset("sHallOfFame1Mon1DVs", "sHallOfFame1Mon1")).toBe(3);
    expect(offset("sHallOfFame1Mon1Level", "sHallOfFame1Mon1")).toBe(5);
    expect(offset("sHallOfFame1Mon1Nickname", "sHallOfFame1Mon1")).toBe(6);
    expect(offset("sHallOfFameEnd", "sHallOfFame")).toBe(
      LAYOUT.hallOfFame * LAYOUT.hallOfFameTeams,
    );
    expect(offset("wMap2Object", "wMap1Object")).toBe(LAYOUT.mapObject);
    expect(offset("wMap1ObjectStructID", "wMap1Object")).toBe(
      LAYOUT.mapObjectStruct,
    );
    expect(offset("wMap1ObjectYCoord", "wMap1Object")).toBe(LAYOUT.mapObjectY);
    expect(offset("wMap1ObjectXCoord", "wMap1Object")).toBe(LAYOUT.mapObjectX);
    expect(offset("wMap1Object", "wMapObjects")).toBe(LAYOUT.mapObject);
    expect(offset("wObject1Struct", "wPlayerStruct")).toBe(LAYOUT.object);
    expect(offset("wObject1Direction", "wObject1Struct")).toBe(
      LAYOUT.objectDirection,
    );
    expect(offset("wObject1MapX", "wObject1Struct")).toBe(LAYOUT.objectMapX);
    expect(offset("wObject1MapY", "wObject1Struct")).toBe(LAYOUT.objectMapY);
    expect(offset("wRoamMon2", "wRoamMon1")).toBe(LAYOUT.roamMon);
    expect(offset("sPartyMon2Mail", "sPartyMon1Mail")).toBe(
      SAV.MAIL_STRUCT_LENGTH,
    );
    expect(offset("sPartyMon1MailLineBreak", "sPartyMon1Mail")).toBe(
      SAV.MAIL_LINE_LENGTH,
    );
    expect(offset("sPartyMon1MailAuthor", "sPartyMon1Mail")).toBe(
      2 * SAV.MAIL_LINE_LENGTH + 1,
    );
    expect(offset("sPartyMon1MailAuthorID", "sPartyMon1MailAuthor")).toBe(
      SAV.PLAYER_NAME_LENGTH + 2,
    );
    expect(offset("sPartyMon1MailSpecies", "sPartyMon1MailAuthorID")).toBe(2);
    expect(offset("sPartyMon1MailType", "sPartyMon1MailAuthorID")).toBe(3);
    // The saved block is one copy of three adjacent WRAM blocks.
    expect(at("wPlayerDataEnd")).toBe(at("wCurMapData"));
    expect(at("wCurMapDataEnd")).toBe(at("wPokemonData"));
    expect(SRAM.sGameDataEnd - SRAM.sGameData).toBe(
      SAVE_BLOCK.wPokemonDataEnd - SAVE_BLOCK.wPlayerData,
    );
    expect(offset("wTextboxFrame", "wOptions")).toBe(2);
    expect(at("wRoamMons_CurMapGroup")).toBe(SAVE_BLOCK.wRoamMons_CurMapNumber + 1);
    expect(at("wBestMagikarpLengthInches")).toBe(
      SAVE_BLOCK.wBestMagikarpLengthFeet + 1,
    );
  });
});

describe.skipIf(!existsSync(romPath))("cartridge saves with the local ROM", () => {
  const assets = existsSync(romPath)
    ? new CrystalAssets(new Uint8Array(readFileSync(romPath)))
    : undefined!;
  const cartridge = () => new Uint8Array(readFileSync(cartridgePath));
  const now = new Date(2026, 9, 17, 12, 30, 0);
  const world = (save: NativeSave) => {
    const game = new GameWorld(assets, () => now);
    game.restore(save);
    return game;
  };
  /** A byte of the main copy of the saved block. */
  const main = (address: number) =>
    SRAM.sGameData + address - SAVE_BLOCK.wPlayerData;
  /** SaveChecksum over the main copy. */
  const sign = (file: Uint8Array) => {
    let sum = 0;
    for (let p = SRAM.sGameData; p < SRAM.sGameDataEnd; p++)
      sum = (sum + file[p]) & 0xffff;
    file[SRAM.sChecksum] = sum & 0xff;
    file[SRAM.sChecksum + 1] = sum >> 8;
    return file;
  };
  /** The port's day number, as GameWorld computes it. */
  const nativeDay = (save: NativeSave) => {
    const game = new Date(now.getTime() + save.clock.minuteOffset * 60_000);
    return (
      Math.floor(
        Date.UTC(game.getFullYear(), game.getMonth(), game.getDate()) /
          86_400_000,
      ) + save.clock.weekdayOffset
    );
  };
  /** An MBC3 footer as VBA-M, mGBA and BGB write it. */
  const footer = (
    registers: [number, number, number, number, number],
    timestamp: number,
    length = 48,
  ) => {
    const bytes = new Uint8Array(length);
    const view = new DataView(bytes.buffer);
    registers.forEach((value, i) => {
      view.setUint32(i * 4, value, true);
      view.setUint32(20 + i * 4, value, true);
    });
    if (length === 48) view.setBigUint64(40, BigInt(timestamp), true);
    else view.setUint32(40, timestamp, true);
    return bytes;
  };
  const withFooter = (file: Uint8Array, extra: Uint8Array) => {
    const joined = new Uint8Array(file.length + extra.length);
    joined.set(file);
    joined.set(extra, file.length);
    return joined;
  };

  it.skipIf(!existsSync(cartridgePath))(
    "converts the committed cartridge save into a game that loads",
    () => {
      const result = convertCartridgeSave(assets, cartridge(), now);
      expect(result.copy).toBe("main");
      expect(result.clock).toBe("device");
      const { save } = result;
      expect(save).toMatchObject({
        map: "24:4",
        x: 13,
        y: 6,
        name: "Mattiaᴾᴷ",
        avatar: "chris",
        playerId: 8872,
        rivalName: "ARGENTO",
        gameTime: { hours: 79, minutes: 32, seconds: 56, frames: 20 },
        hallOfFame: true,
      });
      expect(save.party.map((mon) => [mon.species, mon.level])).toEqual([
        [157, 100],
        [164, 100],
        [226, 100],
        [248, 100],
        [225, 100],
        [210, 100],
      ]);
      expect(save.party.every((mon) => mon.ot === "Mattiaᴾᴷ")).toBe(true);
      expect(save.pokedex.caught).toHaveLength(251);
      for (let bit = 0; bit < 16; bit++)
        expect(save.flags).toContain(27 + bit);
      expect(world(save).describe()).toEqual({
        player: "Mattiaᴾᴷ",
        playerId: 8872,
        place: "NEW BARK TOWN",
        hours: 79,
        minutes: 32,
        badges: 8,
        caught: 251,
        newGame: false,
      });
      // Its saved game is exactly what the port keeps after loading it,
      // but for the roaming Pokémon, which Continue's JumpRoamMons moves
      // as the cartridge's does.
      const loaded = world(save).save();
      expect(loaded).toEqual({
        ...save,
        roamMons: loaded.roamMons,
        roamMonsMap: loaded.roamMonsMap,
      });
    },
  );

  it.skipIf(!existsSync(virtualConsolePath))(
    "reads the 3DS Virtual Console's sav.dat like the plain save",
    () => {
      const vc = convertCartridgeSave(
        assets,
        new Uint8Array(readFileSync(virtualConsolePath)),
        now,
      );
      expect(vc.save).toEqual(convertCartridgeSave(assets, cartridge(), now).save);
      expect(vc.clock).toBe("device");
    },
  );

  it.skipIf(!existsSync(cartridgePath))(
    "falls back to the backup copy and refuses two damaged copies",
    () => {
      const expected = convertCartridgeSave(assets, cartridge(), now).save;
      const damaged = cartridge();
      damaged[main(SAVE_BLOCK.wMoney)] ^= 1;
      const backup = convertCartridgeSave(assets, damaged, now);
      expect(backup.copy).toBe("backup");
      expect(backup.save).toEqual(expected);
      expect(backup.notes[0]).toContain("backup");
      damaged[SRAM.sBackupGameData + 5] ^= 1;
      expect(() => convertCartridgeSave(assets, damaged, now)).toThrow(
        "Both copies of this save fail their checksums",
      );
      expect(() =>
        convertCartridgeSave(assets, new Uint8Array(0x8000).fill(0xff), now),
      ).toThrow("holds no saved game");
      expect(() =>
        convertCartridgeSave(assets, new Uint8Array(0x4000), now),
      ).toThrow(CartridgeSaveError);
    },
  );

  it.skipIf(!existsSync(cartridgePath))(
    "carries the cartridge clock forward from an emulator footer",
    () => {
      const file = cartridge();
      // wStartDay, wStartHour, wStartMinute and wStartSecond of this save.
      expect([
        ...file.subarray(main(SAVE_BLOCK.wStartDay), main(SAVE_BLOCK.wStartDay) + 4),
      ]).toEqual([6, 23, 18, 10]);
      const written = Math.floor(now.getTime() / 1000) - 3600;
      // 3 days 1:41:50 an hour ago is 3 days 2:41:50 now; FixTime adds
      // 6 days 23:18:10 with carries: day 10 (a Wednesday), 2:00:00.
      for (const length of [48, 44]) {
        const result = convertCartridgeSave(
          assets,
          withFooter(file, footer([50, 41, 1, 3, 0], written, length)),
          now,
        );
        expect(result.clock).toBe("rtc");
        expect(world(result.save).clock()).toEqual({
          weekday: 3,
          hours: 2,
          minutes: 0,
        });
      }
      // A halted clock does not move; FixDays takes 300 days modulo 140:
      // day 20 + 6 = 26 (a Friday), 0:00:00 + 23:18:10.
      const halted = convertCartridgeSave(
        assets,
        withFooter(file, footer([0, 0, 0, 44, 0x41], 0)),
        now,
      );
      expect(world(halted.save).clock()).toEqual({
        weekday: 5,
        hours: 23,
        minutes: 18,
      });
      // Without a footer, this device's time and the saved day (17, a
      // Wednesday) are used.
      const plain = convertCartridgeSave(assets, file, now);
      expect(world(plain.save).clock()).toEqual({
        weekday: 3,
        hours: 12,
        minutes: 30,
      });
      expect(() =>
        convertCartridgeSave(
          assets,
          withFooter(file, footer([60, 0, 0, 0, 0], written)),
          now,
        ),
      ).toThrow("clock data is damaged");
    },
  );

  it.skipIf(!existsSync(cartridgePath))(
    "moves day countdowns onto the port's day number",
    () => {
      const file = cartridge();
      const today = file[main(SAVE_BLOCK.wCurDay)];
      expect(today).toBe(17);
      // The Lucky Number countdown started two days ago with 5 days.
      file[main(SAVE_BLOCK.wLuckyNumberDayTimer)] = 5;
      file[main(SAVE_BLOCK.wLuckyNumberDayTimer) + 1] = today - 2;
      // The daily reset ran today.
      file[main(SAVE_BLOCK.wDailyResetTimer)] = 1;
      file[main(SAVE_BLOCK.wDailyResetTimer) + 1] = today;
      // The lucky number was drawn today (wCurDay + 1).
      file[SRAM.sLuckyNumberDay] = today + 1;
      const { save } = convertCartridgeSave(assets, sign(file), now);
      const day = nativeDay(save);
      expect(
        checkCountdown(save.timers.luckyNumber, day).timer.remaining,
      ).toBe(3);
      expect(save.dailyReset).toBe(day);
      expect(save.luckyNumber.day).toBe(rtcDay(day) + 1);
      // A reset that last ran yesterday is due at the next check.
      file[main(SAVE_BLOCK.wDailyResetTimer) + 1] = today - 1;
      expect(convertCartridgeSave(assets, sign(file), now).save.dailyReset).toBe(
        null,
      );
    },
  );

  it.skipIf(!existsSync(cartridgePath))(
    "refuses saves the port cannot continue, with the reason",
    () => {
      const contest = cartridge();
      const entry = SYMBOLS.engineFlags + ENGINE_FLAGS.bugContestTimer * 3;
      contest[main(assets.reader.word(entry))] |= assets.reader.byte(entry + 2);
      expect(() => convertCartridgeSave(assets, sign(contest), now)).toThrow(
        "Bug-Catching Contest",
      );
      const tower = cartridge();
      tower[SRAM.sBattleTowerChallengeState] = 2;
      expect(() => convertCartridgeSave(assets, tower, now)).toThrow(
        "Battle Tower challenge",
      );
      // Any decoded map the port has not opened.
      const closed = cartridge();
      let unported = "";
      for (let group = 1; group <= 26 && !unported; group++)
        for (let number = 1; number <= 3 && !unported; number++)
          if (!assets.isPorted(`${group}:${number}`)) {
            try {
              assets.map(`${group}:${number}`);
              unported = `${group}:${number}`;
            } catch {
              // Not a map.
            }
          }
      const [group, number] = unported.split(":").map(Number);
      closed[main(SAVE_BLOCK.wMapGroup)] = group;
      closed[main(SAVE_BLOCK.wMapGroup) + 1] = number;
      expect(() => convertCartridgeSave(assets, sign(closed), now)).toThrow(
        "cannot open yet",
      );
      const glyph = cartridge();
      glyph[main(SAVE_BLOCK.wBoxNames)] = 0xd0; // 'd, not on the naming screen
      expect(() => convertCartridgeSave(assets, sign(glyph), now)).toThrow(
        "Box 1's name uses a character the port cannot show yet",
      );
    },
  );
});