import { NextRequest, NextResponse } from 'next/server';
import { getServerSession } from 'next-auth';
import { authOptions } from '@/lib/auth';
import { uploadToS3 } from '@/lib/s3';
import path from 'path';
import { assertBoundedMultipartHeaders, assertMultipartFiles } from '@/lib/multipart-request-guard';
import {
  boundedMultipartRequestLimiter,
  getBoundedMultipartFailure,
  MULTIPART_ROUTE_LIMITS,
} from '@/lib/multipart-route-limits';

// POST - 上传文件到 S3
// 任务-详情类型：保持原图质量，不做压缩处理，确保素材完整性
export async function POST(request: NextRequest) {
  let releaseRequestSlot: (() => void) | null = null;
  try {
    const session = await getServerSession(authOptions);
    if (!session) {
      return NextResponse.json({ error: '请先登录' }, { status: 401 });
    }

    assertBoundedMultipartHeaders(request.headers, MULTIPART_ROUTE_LIMITS.legacyS3RequestBytes);
    releaseRequestSlot = await boundedMultipartRequestLimiter.acquire();
    const formData = await request.formData();
    assertMultipartFiles(formData, {
      fields: {
        file: {
          maxCount: 1,
          maxFileBytes: MULTIPART_ROUTE_LIMITS.legacyS3FileBytes,
          allowedMimeTypes: ['image/jpeg', 'image/png', 'image/webp', 'image/tiff', 'image/avif'],
        },
      },
      maxFiles: 1,
      maxTotalBytes: MULTIPART_ROUTE_LIMITS.legacyS3FileBytes,
    });
    const file = formData.get('file') as File;
    const type = formData.get('type') as string; // main/sku/detail

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

    // 文件大小检查（任务-详情允许较大文件，最大100MB）
    if (file.size > MULTIPART_ROUTE_LIMITS.legacyS3FileBytes) {
      return NextResponse.json(
        { error: `图片过大，请使用小于100MB的图片` },
        { status: 400 }
      );
    }

    // 读取文件buffer
    const buffer = Buffer.from(await file.arrayBuffer());
    
    // 获取原始文件扩展名
    const originalExt = path.extname(file.name).toLowerCase() || '.jpg';
    // 保持原始格式，不转换为webp
    const mimeType = file.type || 'image/jpeg';
    
    console.log(`[S3 Upload] ========== Processing file (NO COMPRESSION) ==========`);
    console.log(`[S3 Upload] Type: ${type}`);
    console.log(`[S3 Upload] Original fileName: ${file.name}`);
    console.log(`[S3 Upload] Original file size: ${buffer.length} bytes (${(buffer.length / 1024 / 1024).toFixed(2)} MB)`);
    console.log(`[S3 Upload] MIME type: ${mimeType}`);
    console.log(`[S3 Upload] 任务-详情类型：保持原图质量，不做压缩处理`);

    // 生成文件路径（保持原始格式）
    const timestamp = Date.now();
    const randomSuffix = Math.random().toString(36).substring(2, 9); // 7位随机字符串
    const fileName = `${type}-${timestamp}-${randomSuffix}${originalExt}`;
    const s3Path = `product-package/${fileName}`;
    
    console.log(`[S3 Upload] Generated fileName: ${fileName}`);
    console.log(`[S3 Upload] S3 path: ${s3Path}`);
    
    // 直接上传原图到 S3（不压缩）
    const url = await uploadToS3(buffer, s3Path, mimeType);
    
    console.log(`[S3 Upload] Uploaded successfully: url=${url}`);
    console.log(`[S3 Upload] ====================================`);

    return NextResponse.json({ url });
  } catch (error) {
    console.error('[S3 Upload] Error:', error);
    const boundedFailure = getBoundedMultipartFailure(error);
    if (boundedFailure) {
      return NextResponse.json(
        { error: boundedFailure.message, code: boundedFailure.code },
        {
          status: boundedFailure.status,
          ...(boundedFailure.retryAfterSeconds
            ? { headers: { 'Retry-After': String(boundedFailure.retryAfterSeconds) } }
            : {}),
        },
      );
    }
    return NextResponse.json(
      { error: '上传失败: ' + (error instanceof Error ? error.message : '未知错误') },
      { status: 500 }
    );
  } finally {
    releaseRequestSlot?.();
  }
}