import { test } from 'node:test';
import assert from 'node:assert/strict';
import { join } from 'node:path';
import { mkdirSync, writeFileSync, readFileSync, existsSync, rmSync, mkdtempSync, symlinkSync } from 'node:fs';
import { tmpdir } from 'node:os';
import { platform } from 'node:process';
import { deflateSync } from 'node:zlib';
import { materialize, composeSkin, SkinValidationError } from '../lib/materialize.mjs';

const LINK_TYPE = platform === 'win32' ? 'junction' : 'dir';

function crc32(buf) {
  let c = ~0;
  for (const x of buf) { c ^= x; for (let i = 0; i < 8; i++) c = (c >>> 1) ^ (0xEDB88320 & -(c & 1)); }
  return ~c >>> 0;
}
function chunk(type, data) {
  const len = Buffer.alloc(4); len.writeUInt32BE(data.length);
  const td = Buffer.concat([Buffer.from(type, 'ascii'), data]);
  const c = Buffer.alloc(4); c.writeUInt32BE(crc32(td));
  return Buffer.concat([len, td, c]);
}
function makePng(w, h, rgb = [0, 0, 0]) {
  const ihdr = Buffer.alloc(13);
  ihdr.writeUInt32BE(w, 0); ihdr.writeUInt32BE(h, 4); ihdr[8] = 8; ihdr[9] = 2;
  const raw = Buffer.alloc(h * (1 + w * 3));
  for (let y = 0; y < h; y++) {
    const off = y * (1 + w * 3);
    raw[off] = 0;
    for (let x = 0; x < w; x++) {
      raw[off + 1 + x * 3] = rgb[0]; raw[off + 2 + x * 3] = rgb[1]; raw[off + 3 + x * 3] = rgb[2];
    }
  }
  return Buffer.concat([
    Buffer.from([137, 80, 78, 71, 13, 10, 26, 10]),
    chunk('IHDR', ihdr), chunk('IDAT', deflateSync(raw)), chunk('IEND', Buffer.alloc(0)),
  ]);
}

const DEFAULT_BTN = makePng(64, 64, [1, 2, 3]);
const DEFAULT_BG = makePng(64, 64, [4, 5, 6]);
const SKINNED_BTN = makePng(64, 64, [9, 9, 9]);

function put(dir, rel, content) {
  const p = join(dir, ...rel.split('/'));
  mkdirSync(join(p, '..'), { recursive: true });
  writeFileSync(p, content);
}
function read(dir, rel) { return readFileSync(join(dir, ...rel.split('/')), 'utf8'); }
function readBinary(dir, rel) { return readFileSync(join(dir, ...rel.split('/'))); }

/** 造一个「框架真源 + 挂 junction 的子游戏工程」的临时环境 */
function scaffold() {
  const root = mkdtempSync(join(tmpdir(), 'youle-mat-'));
  const frameworkSrc = join(root, 'nexus', 'assets', 'framework');
  mkdirSync(frameworkSrc, { recursive: true });
  put(frameworkSrc, 'ui/atlas-hall/btn.png', DEFAULT_BTN);
  put(frameworkSrc, 'ui/atlas-hall/btn.png.meta', '{"uuid":"fw-btn-uuid"}');
  put(frameworkSrc, 'ui/atlas-hall/bg.png', DEFAULT_BG);
  put(frameworkSrc, 'core/net.ts', 'export const x=1;');

  const gameDir = join(root, 'games', 'demo');
  mkdirSync(join(gameDir, 'assets'), { recursive: true });
  writeFileSync(join(gameDir, 'package.json'), JSON.stringify({ name: 'demo', creator: { version: '3.8.8' } }));
  symlinkSync(frameworkSrc, join(gameDir, 'assets', 'framework'), LINK_TYPE);
  put(gameDir, 'assets/game/theme.ts', 'export const theme={};');
  mkdirSync(join(gameDir, 'library'), { recursive: true });   // 缓存目录，应被跳过
  writeFileSync(join(gameDir, 'library', 'junk'), 'x');

  return { root, frameworkSrc, gameDir, dest: join(root, 'workspace', 'demo') };
}
function cleanup(root) { rmSync(root, { recursive: true, force: true }); }

test('materialize 把 junction 变成真实目录拷贝，并跳过缓存目录', () => {
  const s = scaffold();
  try {
    materialize(s.gameDir, s.frameworkSrc, s.dest);
    assert.ok(readBinary(s.dest, 'assets/framework/ui/atlas-hall/btn.png').equals(DEFAULT_BTN), '框架 btn.png 被正确拷贝');
    assert.equal(read(s.dest, 'assets/game/theme.ts'), 'export const theme={};', '游戏资源被拷贝');
    assert.ok(!existsSync(join(s.dest, 'library')), 'library 应被跳过');
  } finally { cleanup(s.root); }
});

test('materialize 只跳过工程根的缓存目录，不吞 assets 下的同名业务目录', () => {
  const s = scaffold();
  try {
    put(s.gameDir, 'assets/game/native/bridge.ts', 'BRIDGE');
    materialize(s.gameDir, s.frameworkSrc, s.dest);
    assert.equal(read(s.dest, 'assets/game/native/bridge.ts'), 'BRIDGE', 'assets 下的 native 是业务目录，必须保留');
    assert.ok(!existsSync(join(s.dest, 'library')), '工程根的 library 仍应被跳过');
  } finally { cleanup(s.root); }
});

test('materialize 后写临时工程不影响框架真源', () => {
  const s = scaffold();
  try {
    materialize(s.gameDir, s.frameworkSrc, s.dest);
    writeFileSync(join(s.dest, 'assets', 'framework', 'ui', 'atlas-hall', 'btn.png'), Buffer.from('MUTATED'));
    assert.ok(readBinary(s.frameworkSrc, 'ui/atlas-hall/btn.png').equals(DEFAULT_BTN), '真源必须只读');
  } finally { cleanup(s.root); }
});

test('materialize 拒绝覆盖已存在的目标目录', () => {
  const s = scaffold();
  try {
    materialize(s.gameDir, s.frameworkSrc, s.dest);
    assert.throws(() => materialize(s.gameDir, s.frameworkSrc, s.dest), /已存在/);
  } finally { cleanup(s.root); }
});

test('composeSkin 用 override 覆盖框架资源内容，保留框架 .meta', () => {
  const s = scaffold();
  try {
    put(s.gameDir, 'assets/game/override/atlas-hall/btn.png', SKINNED_BTN);
    materialize(s.gameDir, s.frameworkSrc, s.dest);
    const r = composeSkin(s.dest);
    assert.deepEqual(r.matched, ['atlas-hall/btn.png'], 'matched 返回覆盖的文件');
    assert.equal(r.frameworkTotal, 2, '框架资源总数');
    assert.ok(readBinary(s.dest, 'assets/framework/ui/atlas-hall/btn.png').equals(SKINNED_BTN), '框架文件被 override 替换');
    assert.equal(read(s.dest, 'assets/framework/ui/atlas-hall/btn.png.meta'), '{"uuid":"fw-btn-uuid"}', 'meta 文件不变');
    assert.ok(readBinary(s.dest, 'assets/framework/ui/atlas-hall/bg.png').equals(DEFAULT_BG), '未覆盖的保持默认');
  } finally { cleanup(s.root); }
});

test('composeSkin 例外通道：override 自带 meta 时，uuid 被改回框架的值', () => {
  const s = scaffold();
  try {
    put(s.gameDir, 'assets/game/override/atlas-hall/btn.png', SKINNED_BTN);
    put(s.gameDir, 'assets/game/override/atlas-hall/btn.png.meta', '{"uuid":"game-own-uuid","ver":"1.0.0"}');
    materialize(s.gameDir, s.frameworkSrc, s.dest);
    composeSkin(s.dest);
    const meta = JSON.parse(read(s.dest, 'assets/framework/ui/atlas-hall/btn.png.meta'));
    assert.equal(meta.uuid, 'fw-btn-uuid', 'uuid 必须沿用框架的');
    assert.equal(meta.ver, '1.0.0', 'override meta 的其余字段保留');
  } finally { cleanup(s.root); }
});

test('composeSkin 校验不过时抛 SkinValidationError 且不写任何文件', () => {
  const s = scaffold();
  try {
    // 同时放入一个合法的 override 和一个孤儿 override
    put(s.gameDir, 'assets/game/override/atlas-hall/btn.png', SKINNED_BTN);    // 合法：框架里有此文件
    put(s.gameDir, 'assets/game/override/atlas-hall/typo.png', DEFAULT_BG);   // 孤儿：框架里无此文件
    materialize(s.gameDir, s.frameworkSrc, s.dest);
    let validationErr;
    assert.throws(() => {
      try {
        composeSkin(s.dest);
      } catch (err) {
        validationErr = err;
        throw err;
      }
    }, SkinValidationError);

    // 验证错误中确实有 orphan 错误指向孤儿文件
    assert.ok(validationErr.errors.some(e => e.code === 'orphan' && e.path === 'atlas-hall/typo.png'), 'orphan 错误必须被检测');

    // 验证即使合法的 btn.png 也没有被写入（校验失败时不得部分写入）
    assert.ok(readBinary(s.dest, 'assets/framework/ui/atlas-hall/btn.png').equals(DEFAULT_BTN), '校验失败时不得部分写入：btn.png 应仍为框架默认值');
  } finally { cleanup(s.root); }
});