import { NextRequest, NextResponse } from 'next/server';
import fs from 'fs/promises';
import path from 'path';
import sharp from 'sharp';

const UPLOAD_DIR = path.join(process.cwd(), 'public/uploads');
const MAX_SIZE = 5 * 1024 * 1024; // 5MB

export async function POST(request: NextRequest) {
  try {
    const formData = await request.formData();
    const file = formData.get('file') as File | null;

    if (!file) {
      return NextResponse.json({ error: '请选择图片' }, { status: 400 });
    }

    const allowedTypes = ['image/jpeg', 'image/png', 'image/gif', 'image/webp'];
    if (!allowedTypes.includes(file.type)) {
      return NextResponse.json({ error: '仅支持 JPG、PNG、GIF、WebP 格式' }, { status: 400 });
    }

    const ext = 'jpg';
    const filename = `${Date.now()}-${Math.random().toString(36).slice(2)}.${ext}`;
    const filepath = path.join(UPLOAD_DIR, filename);

    const buffer = await file.arrayBuffer();
    let imageBuffer = Buffer.from(buffer);

    // 获取图片尺寸
    const image = sharp(imageBuffer);
    const metadata = await image.metadata();

    // 如果超过5MB，进行压缩
    if (imageBuffer.length > MAX_SIZE) {
      let quality = 85;

      // 先尝试缩小尺寸
      if (metadata.width && metadata.width > 1920) {
        imageBuffer = await image
          .resize(1920, null, { withoutEnlargement: true })
          .toBuffer() as any;
      }

      // 循环压缩直到小于5MB
      while (imageBuffer.length > MAX_SIZE && quality > 30) {
        imageBuffer = await sharp(imageBuffer)
          .jpeg({ quality, progressive: true })
          .toBuffer() as any;
        quality -= 10;
      }

      // 如果还是太大，继续缩小尺寸
      if (imageBuffer.length > MAX_SIZE && metadata.width && metadata.width > 800) {
        imageBuffer = await sharp(imageBuffer)
          .resize(800, null, { withoutEnlargement: true })
          .jpeg({ quality: 70, progressive: true })
          .toBuffer() as any;
      }
    } else {
      // 转换为jpeg并优化
      imageBuffer = await sharp(imageBuffer)
        .jpeg({ quality: 85, progressive: true })
        .toBuffer() as any;
    }

    await fs.writeFile(filepath, imageBuffer);

    // 返回相对路径
    const url = `/uploads/${filename}`;
    return NextResponse.json({ url });
  } catch (error) {
    console.error('Upload error:', error);
    return NextResponse.json({ error: '上传失败' }, { status: 500 });
  }
}

export async function DELETE(request: NextRequest) {
  try {
    const { searchParams } = new URL(request.url);
    const filename = searchParams.get('filename');

    if (!filename) {
      return NextResponse.json({ error: '缺少文件名' }, { status: 400 });
    }

    const filepath = path.join(UPLOAD_DIR, path.basename(filename));
    await fs.unlink(filepath);

    return NextResponse.json({ success: true });
  } catch (error) {
    console.error('Delete error:', error);
    return NextResponse.json({ error: '删除失败' }, { status: 500 });
  }
}