import sharp from 'sharp';
import fs from 'fs';

/**
 * 压缩图片到目标大小左右
 * @param inputPath 输入文件路径
 * @param outputPath 输出文件路径
 * @param targetSize 目标大小（字节），默认100KB
 */
export async function compressImage(
  inputPath: string,
  outputPath: string,
  targetSize: number = 100 * 1024
): Promise<{ success: boolean; finalSize?: number; error?: string }> {
  try {
    let quality = 80;
    let compressedSize = targetSize + 1;

    // 获取图片信息
    const metadata = await sharp(inputPath).metadata();
    let width = metadata.width;
    let height = metadata.height;

    // 如果图片尺寸较大，先调整尺寸
    if (width && height && (width > 2000 || height > 2000)) {
      width = Math.round(width * 0.5);
      height = Math.round(height * 0.5);
    }

    while (compressedSize > targetSize && quality > 10) {
      await sharp(inputPath)
        .resize(width, height, {
          fit: 'inside',
          withoutEnlargement: true,
        })
        .jpeg({
          quality: quality,
          mozjpeg: true,
        })
        .toFile(outputPath);

      // 获取压缩后文件大小
      const stats = fs.statSync(outputPath);
      compressedSize = stats.size;

      // 如果仍然大于目标大小，降低质量继续压缩
      if (compressedSize > targetSize) {
        quality -= 15;
        if (quality < 10) quality = 10;
      }
    }

    return { success: true, finalSize: compressedSize };
  } catch (error) {
    return {
      success: false,
      error: error instanceof Error ? error.message : '压缩失败',
    };
  }
}