import { test, expect } from "@playwright/test";
import { existsSync, readFileSync } from "node:fs";
import { CrystalAssets } from "../src/game/rom/assets";

const romPath =
  process.env.CRYSTAL_ROM_PATH ??
  "Pokemon - Crystal Version (UE) (V1.1) [C][!].gbc";
const symbolsPath = ".reference/pokecrystal/pokecrystal11.sym";
test("all tileset palettes match the original LoadMapPals routine", async ({
  page,
}, info) => {
  test.skip(
    info.project.name !== "chromium" ||
      !existsSync(romPath) ||
      !existsSync(symbolsPath),
    "Requires the local ROM/reference; engine comparison runs in Chromium.",
  );
  const symbols: Record<string, { bank: number; address: number }> = {};
  for (const line of readFileSync(symbolsPath, "utf8").split("\n")) {
    const m = /^([0-9a-f]{2}):([0-9a-f]{4}) (\S+)$/.exec(line);
    if (m)
      symbols[m[3]] = { bank: parseInt(m[1], 16), address: parseInt(m[2], 16) };
  }
  const bytes = new Uint8Array(readFileSync(romPath));
  const cases = Array.from({ length: 36 * 4 }, (_, i) => ({
    tileset: 1 + Math.floor(i / 4),
    time: i % 4,
    environment: 3,
    group: 24,
  }));
  for (const environment of [1, 2, 4, 7])
    for (const time of [0, 1, 2, 3])
      for (const tileset of [1, 29, 30])
        cases.push({ tileset, time, environment, group: 24 });
  await page.goto("/reference.html");
  const original = await page.evaluate(
    async ({ rom, symbols, cases }) => {
      const { BinjgbEmulator } = await import("/src/emulator/binjgb.ts");
      const emu = new BinjgbEmulator();
      await emu.load(new Uint8Array(rom), document.createElement("canvas"));
      const write = (name: string, value: number) =>
        emu.writeMemory(symbols[name].address, value);
      const target = symbols.LoadMapPals;
      const program = [
        0xf3,
        0x31,
        0xfe,
        0xc7,
        0x3e,
        target.bank,
        0xe0,
        0x9d,
        0xea,
        0,
        0x20,
        0xcd,
        target.address & 255,
        target.address >> 8,
        0x3e,
        0x42,
        0xea,
        0xff,
        0xc6,
        0x18,
        0xfe,
      ];
      const output = cases.map((c) => {
        emu.writeMemory(0xff70, 1);
        write("wMapTileset", c.tileset);
        write("wEnvironment", c.environment);
        write("wTimeOfDayPal", c.time);
        write("wMapGroup", c.group);
        emu.writeMemory(0xc6ff, 0);
        program.forEach((v, i) => emu.writeMemory(0xc000 + i, v));
        emu.setProgramCounter(0xc000);
        emu.advanceFrames(2);
        if (emu.readMemory(0xc6ff) !== 0x42)
          throw new Error("LoadMapPals did not return");
        emu.writeMemory(0xff70, symbols.wBGPals1.bank);
        return Array.from({ length: 32 }, (_, i) => {
          const p = symbols.wBGPals1.address + i * 2;
          const value = emu.readMemory(p) | (emu.readMemory(p + 1) << 8);
          return [0, 5, 10].map((shift) =>
            Math.round((((value >> shift) & 31) * 255) / 31),
          );
        });
      });
      emu.dispose();
      return output;
    },
    { rom: [...bytes], symbols, cases },
  );
  const assets = new CrystalAssets(bytes),
    base = assets.map("24:6");
  cases.forEach((c, i) =>
    expect(
      assets.palettes({ ...base, ...c }, c.time).flat(),
      JSON.stringify(c),
    ).toEqual(original[i]),
  );
});