import path from 'path';
import fs from 'fs';

export function autoIncludeTSPlugin (options) {
  // options: { entries: [{ entry: 'napcat.ts', dir: './utils' }, ...] }
  const { entries } = options;
  let tsFilesMap = {};

  return {
    name: 'vite-auto-include',

    async buildStart () {
      tsFilesMap = {};
      for (const { entry, dir } of entries) {
        if (!tsFilesMap[entry]) {
          tsFilesMap[entry] = [];
        }
        const fullDir = path.resolve(dir);
        const allTsFiles = await findTSFiles(fullDir);

        const validFiles = [];
        allTsFiles.forEach((filePath) => {
          try {
            const source = fs.readFileSync(filePath, 'utf-8');
            if (source && source.trim() !== '') {
              validFiles.push(filePath);
            } else {
              // Skipping empty file: ${filePath}
            }
          } catch (error) {
            console.error(`Error reading file: ${filePath}`, error);
          }
        });

        tsFilesMap[entry].push(...validFiles);
      }
    },

    transform (code, id) {
      for (const [entry, tsFiles] of Object.entries(tsFilesMap)) {
        const isMatch = id.endsWith(entry) || id.includes(entry);
        if (isMatch && tsFiles.length > 0) {
          const imports = tsFiles.map(filePath => {
            const relativePath = path.relative(path.dirname(id), filePath).replace(/\\/g, '/');
            return `import './${relativePath}';`;
          }).join('\n');

          const transformedCode = imports + '\n' + code;

          return {
            code: transformedCode,
            map: { mappings: '' }, // 空映射即可，VSCode 可以在 TS 上断点
          };
        }
      }

      return null;
    },

  };
}

// 辅助函数：查找所有 .ts 文件
async function findTSFiles (dir) {
  const files = [];
  const items = await fs.promises.readdir(dir, { withFileTypes: true });

  for (const item of items) {
    const fullPath = path.join(dir, item.name);
    if (item.isDirectory()) {
      files.push(...await findTSFiles(fullPath)); // 递归查找子目录
    } else if (item.isFile() && fullPath.endsWith('.ts')) {
      files.push(fullPath); // 收集 .ts 文件
    }
  }

  return files;
}