import { Provide } from '@midwayjs/core';
import * as fs from 'fs';
import * as path from 'path';
import { v4 as uuidv4 } from 'uuid';

@Provide()
export class UploadService {
  async uploadBase64<T>(
    base64: string,
    filename: string,
    callback: (filePath: string) => Promise<T>
  ): Promise<T> {
    // 从base64字符串中提取数据
    const matches = base64.match(/^data:(.+);base64,(.+)$/);
    if (!matches || matches.length !== 3) {
      throw new Error('Invalid base64 string');
    }

    // 解码base64数据
    const buffer = Buffer.from(matches[2], 'base64');
    
    // 创建一个唯一的文件名
    const uniqueFilename = `${uuidv4()}-${filename}`;
    const filePath = path.join('/tmp', uniqueFilename);

    try {
      // 将文件写入临时目录
      await fs.promises.writeFile(filePath, buffer);
      
      // 执行回调并传递文件路径
      return await callback(filePath);
    } finally {
      // 确保临时文件被删除
      try {
        await fs.promises.unlink(filePath);
      } catch (error) {
        // 如果文件不存在或无法删除,则记录错误
        console.error(`Failed to delete temporary file: ${filePath}`, error);
      }
    }
  }
}