import * as fs from "fs";
import * as path from "path";

/**
 * 默认测试 / story / example / fixture / type 文件匹配规则
 * 仅用于“识别”，不直接决定是否排除
 */
const DEFAULT_TEST_FILE_PATTERNS: RegExp[] = [
  // =========================
  // Test / Spec
  // =========================
  /\.(test|spec)\.(ts|tsx|js|jsx)$/,
  /\.(test|spec)\.(ts|tsx|js|jsx)\?.*$/, // query param safe

  // =========================
  // E2E / Playwright / Cypress
  // =========================
  /\.(cy|playwright|e2e)\.(ts|tsx|js|jsx)$/,

  // =========================
  // Storybook
  // =========================
  /\.(story|stories)\.(ts|tsx|js|jsx|mdx)$/,

  // =========================
  // Snapshot / Mock / Fixture
  // =========================
  /\.snap$/,
  /\.mock\.(ts|tsx|js|jsx)$/,
  /\.fixture\.(ts|tsx|js|jsx)$/,

  // =========================
  // Type declarations
  // =========================
  /\.d\.ts$/,

  // =========================
  // Examples / Demos / Docs
  // =========================
  /\.(example|demo|docs)\.(ts|tsx|js|jsx)$/,
];

/**
 * 测试 / 辅助目录（目录级排除）
 */
const DEFAULT_TEST_DIR_PATTERNS: RegExp[] = [
  /[/\\](__tests__|tests|test|spec|__mocks__|__fixtures__|__snapshots__)[\/\\]/,
  /[/\\](cypress|playwright|e2e|__e2e__|__playwright__)[\/\\]/,
  /[/\\](story|stories|\.storybook)[\/\\]/,
  /[/\\](types|type|typings|interfaces)[\/\\]/,
  /[/\\](examples|example|demo|demos|docs)[\/\\]/,
];

type Config = {
  outputDir: string;
  outputFile: string;
  scanDirs: string[];
  preamble?: string[];
  importPrefix?: string;
  entryFilePatterns?: RegExp[];
  barrelFirstMode?: boolean;
  includeFilePatterns?: RegExp[];
  excludeFilePatterns?: RegExp[];
  excludeDirPatterns?: RegExp[];
};

const tsConfig: Config = {
  outputDir: "src",
  outputFile: "index.ts",
  scanDirs: ["src"],
  importPrefix: "export * from",
  barrelFirstMode: true,
  preamble: ["import './index.css';"],
  entryFilePatterns: [/^index\.(js|ts|jsx|tsx)$/],
  includeFilePatterns: [/\.(js|ts|jsx|tsx)$/],
  excludeFilePatterns: DEFAULT_TEST_FILE_PATTERNS,
  excludeDirPatterns: DEFAULT_TEST_DIR_PATTERNS,
};

const cssConfig: Config = {
  outputDir: "src",
  outputFile: "index.css",
  scanDirs: ["src"],
  importPrefix: "@import",
  barrelFirstMode: false,
  entryFilePatterns: [/^index\.(css)$/],
  includeFilePatterns: [/\.(css)$/],
  excludeFilePatterns: DEFAULT_TEST_FILE_PATTERNS,
  excludeDirPatterns: DEFAULT_TEST_DIR_PATTERNS,
};

function isEntryFile(fileName: string, config: Config): boolean {
  const regExps = config.entryFilePatterns;

  if (!regExps || regExps.length === 0) return false;

  return regExps.some((regExp) => regExp.test(fileName));
}

function isIncludeFile(fileName: string, config: Config): boolean {
  const regExps = config.includeFilePatterns;

  if (!regExps || regExps.length === 0) return false;

  return regExps.some((regExp) => regExp.test(fileName));
}

function isExcludeFile(fileName: string, config: Config): boolean {
  const regExps = config.excludeFilePatterns;

  if (!regExps || regExps.length === 0) return false;

  return regExps.some((regExp) => regExp.test(fileName));
}

function isExcludeDir(filePath: string, config: Config): boolean {
  const regExps = config.excludeDirPatterns;

  if (!regExps || regExps.length === 0) return false;

  return regExps.some((regExp) => regExp.test(filePath));
}

function isValidDir(filePath: string, config: Config): boolean {
  if (isExcludeDir(filePath, config)) {
    return false;
  }
  return true;
}

function isValidFile(fileName: string, config: Config): boolean {
  if (isIncludeFile(fileName, config) && !isExcludeFile(fileName, config)) {
    return true;
  }

  return false;
}

const buildExportStatement = (filePath: string, config: Config) => {
  // 文件夹（不是文件）与目标文件的相对路径
  let exportFilePath = path.relative(config.outputDir, filePath);

  // 去除扩展名，并且转化成正斜杠
  const exportFilePathWithoutExt = path
    .join(
      path.dirname(exportFilePath),
      path.basename(exportFilePath, path.extname(exportFilePath)),
    )
    .replace(/\\/g, "/");

  // 加上 ./ 前缀
  return `${config.importPrefix} './${exportFilePathWithoutExt}';`;
};

function isOutputEntry(filePath: string, config: Config) {
  const outputFilePath = path.resolve(config.outputDir, config.outputFile);
  const targetFilePath = path.resolve(filePath);

  return outputFilePath === targetFilePath;
}

function generateExports(dirPath: string, config: Config): string[] {
  const fileNames = fs.readdirSync(dirPath);
  const exports: string[] = [];

  // =========================
  // 逻辑分支：Barrel First Mode
  // =========================
  if (config.barrelFirstMode) {
    // 查找当前目录有没有 index.ts
    const entryFileName = fileNames.find((fileName) => {
      const filePath = path.join(dirPath, fileName);
      return fs.statSync(filePath).isFile() && isEntryFile(fileName, config);
    });
    // 如果有
    if (entryFileName) {
      const entryFilePath = path.join(dirPath, entryFileName);

      // 如果是 outputFile 自身，则跳过
      if (isOutputEntry(entryFilePath, config)) {
        console.log(`⏭️  跳过自身入口文件: ${entryFilePath}`);
      } else {
        exports.push(buildExportStatement(entryFilePath, config));
      }
    }
  }

  // =========================
  // 逻辑分支：index.ts 不存在，则继续正常遍历与递归
  // =========================
  fileNames.forEach((fileName) => {
    const filePath = path.join(dirPath, fileName);
    const stat = fs.statSync(filePath);

    // 情况1：是文件，且通过了校验
    if (
      stat.isFile() &&
      isValidFile(fileName, config) &&
      !isEntryFile(fileName, config)
    ) {
      exports.push(buildExportStatement(filePath, config));
    }
    // 情况2：是文件夹，且通过了校验，递归扫描子文件夹
    else if (stat.isDirectory() && isValidDir(filePath, config)) {
      const subExports = generateExports(filePath, config);
      exports.push(...subExports);
    }
  });

  return exports;
}

function genIndexFile(config: Config) {
  // 确保输出目录存在，如果不存在就递归创建
  if (!fs.existsSync(config.outputDir)) {
    fs.mkdirSync(config.outputDir, { recursive: true });
  }

  const allExports: string[] = [];

  // 遍历所有需要扫描的根目录
  config.scanDirs.forEach((scanDir) => {
    // 只有当目录真实存在时才进行扫描
    if (fs.existsSync(scanDir)) {
      const exports = generateExports(scanDir, config);
      allExports.push(...exports);
    } else {
      console.warn(`⚠️  警告：扫描目录不存在，已跳过 -> ${scanDir}`);
    }
  });

  // 拼接最终的文件内容：前言 + 导出语句（使用 Set 自动去重）
  const fileContent = [
    ...(config.preamble ?? []),
    ...Array.from(new Set(allExports)),
  ].join("\n");

  // 将内容写入到最终的 index.ts 文件中
  const outputFilePath = path.join(config.outputDir, config.outputFile);
  fs.writeFileSync(outputFilePath, fileContent, "utf-8");

  console.log(`✨ 成功生成入口文件: ${outputFilePath}`);
}

// ================= 脚本执行入口 =================
try {
  console.log("🚀 开始扫描并生成入口文件...");
  genIndexFile(tsConfig);
  genIndexFile(cssConfig);
  console.log("✅ 脚本执行完毕！");
} catch (error) {
  console.error("❌ 脚本执行失败:", error);
  process.exit(1); // 如果报错，让进程以非 0 状态码退出
}