// 上传预览图API
import { NextRequest, NextResponse } from 'next/server';
import { getServerSession } from 'next-auth';
import { authOptions } from '@/lib/auth';
import { uploadToS3 } from '@/lib/s3';
import { compressImage, sanitizeFileName } from '@/lib/image-processor';
import { randomBytes } from 'crypto';
import { assertBoundedMultipartHeaders, assertMultipartFiles } from '@/lib/multipart-request-guard';
import {
  boundedMultipartRequestLimiter,
  getBoundedMultipartFailure,
  MULTIPART_ROUTE_LIMITS,
} from '@/lib/multipart-route-limits';

export const runtime = 'nodejs'
export const dynamic = 'force-dynamic'
export const maxDuration = 10800

// 生成唯一文件名
function generateUniqueFilename(prefix: string, ext: string): string {
  const timestamp = Date.now();
  const random = randomBytes(8).toString('hex');
  return `${prefix}-${timestamp}-${random}${ext}`;
}

// POST - 上传预览图
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.previewRequestBytes);
    releaseRequestSlot = await boundedMultipartRequestLimiter.acquire();
    const formData = await request.formData();
    assertMultipartFiles(formData, {
      fields: {
        file: {
          maxCount: 1,
          maxFileBytes: MULTIPART_ROUTE_LIMITS.previewFileBytes,
          allowedMimeTypes: ['image/*'],
        },
      },
      maxFiles: 1,
      maxTotalBytes: MULTIPART_ROUTE_LIMITS.previewFileBytes,
    });
    const file = formData.get('file') as File;

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

    // 验证文件类型
    if (!file.type.startsWith('image/')) {
      return NextResponse.json(
        { error: '只能上传图片文件' },
        { status: 400 }
      );
    }

    // 验证文件大小（50MB限制）
    if (file.size > MULTIPART_ROUTE_LIMITS.previewFileBytes) {
      return NextResponse.json(
        { error: '预览图过大，请使用小于50MB的图片' },
        { status: 400 }
      );
    }

    // 转换为Buffer
    const buffer = Buffer.from(await file.arrayBuffer());

    // 压缩预览图
    console.log('[Preview Upload] Compressing preview image...');
    const compressedBuffer = await compressImage(buffer, {
      maxSizeKB: 300,
      maxWidth: 1200,
      maxHeight: 1600,
      format: 'webp'
    });

    // 生成文件名并上传到S3
    const filename = generateUniqueFilename('preview', '.webp');
    console.log('[Preview Upload] Uploading compressed preview image to S3...');
    const url = await uploadToS3(compressedBuffer, filename, 'image/webp');

    console.log('[Preview Upload] Preview image uploaded:', url);
    return NextResponse.json({ url });
  } catch (error) {
    console.error('上传预览图失败:', 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，请稍后重试' },
      { status: 500 }
    );
  } finally {
    releaseRequestSlot?.();
  }
}