/**
 * 诊断预览图URL是否可访问
 * GET /api/diagnose/preview-image?url={预览图URL}
 */

import { NextRequest, NextResponse } from 'next/server';
import { getServerSession } from 'next-auth';
import { authOptions } from '@/lib/auth';
import { HeadObjectCommand } from '@aws-sdk/client-s3';
import { s3Client, isS3PublicUrl } from '@/lib/s3';
import { rewriteStorageUrlForClient } from '@/lib/url-rewrite';

export async function GET(request: NextRequest) {
  try {
    const session = await getServerSession(authOptions);
    if (!session) {
      return NextResponse.json(
        { error: '未登录' },
        { status: 401 }
      );
    }

    const url = request.nextUrl.searchParams.get('url');
    if (!url) {
      return NextResponse.json(
        { error: '缺少url参数' },
        { status: 400 }
      );
    }

    const results: any = {
      originalUrl: url,
      checks: [],
    };

    // 1. 检查URL格式
    let parsedUrl: URL;
    try {
      parsedUrl = new URL(url);
      results.checks.push({
        name: 'URL格式',
        status: 'success',
        message: 'URL格式正确',
        details: {
          protocol: parsedUrl.protocol,
          hostname: parsedUrl.hostname,
          pathname: parsedUrl.pathname,
        }
      });
    } catch (error) {
      results.checks.push({
        name: 'URL格式',
        status: 'error',
        message: 'URL格式错误',
        error: error instanceof Error ? error.message : String(error)
      });
      return NextResponse.json(results);
    }

    // 2. 检查URL重写后的地址
    const rewrittenUrl = rewriteStorageUrlForClient(url, request);
    results.rewrittenUrl = rewrittenUrl;
    results.checks.push({
      name: 'URL重写',
      status: rewrittenUrl !== url ? 'success' : 'info',
      message: rewrittenUrl !== url ? 'URL已重写' : 'URL未重写',
      details: {
        original: url,
        rewritten: rewrittenUrl,
      }
    });

    // 3. 检查是否为S3 URL
    const isS3 = isS3PublicUrl(url);
    results.isS3Url = isS3;
    results.checks.push({
      name: 'S3 URL检测',
      status: isS3 ? 'success' : 'info',
      message: isS3 ? '是S3公网URL' : '不是S3公网URL',
    });

    // 4. 如果是S3 URL，检查文件是否存在
    if (isS3) {
      try {
        // 从URL提取key
        const urlObj = new URL(url);
        const key = urlObj.pathname.slice(1); // 移除开头的斜杠

        const command = new HeadObjectCommand({
          Bucket: process.env.S3_BUCKET!,
          Key: key,
        });

        const response = await s3Client.send(command);
        results.checks.push({
          name: 'S3文件存在性',
          status: 'success',
          message: '文件存在于S3',
          details: {
            key: key,
            contentLength: response.ContentLength,
            contentType: response.ContentType,
            lastModified: response.LastModified?.toISOString(),
          }
        });
      } catch (error: any) {
        if (error.name === 'NotFound' || error.$metadata?.httpStatusCode === 404) {
          results.checks.push({
            name: 'S3文件存在性',
            status: 'error',
            message: '文件不存在于S3',
            error: '404 Not Found'
          });
        } else {
          results.checks.push({
            name: 'S3文件存在性',
            status: 'error',
            message: '检查S3文件时出错',
            error: error.message || String(error)
          });
        }
      }
    }

    // 5. 尝试通过HTTP访问（使用重写后的URL）
    if (rewrittenUrl) {
      try {
        const response = await fetch(rewrittenUrl, {
          method: 'HEAD',
          signal: AbortSignal.timeout(5000), // 5秒超时
        });

        results.checks.push({
          name: 'HTTP访问',
          status: response.ok ? 'success' : 'error',
          message: response.ok ? `HTTP访问成功 (${response.status})` : `HTTP访问失败 (${response.status})`,
          details: {
            status: response.status,
            statusText: response.statusText,
            contentType: response.headers.get('content-type'),
            contentLength: response.headers.get('content-length'),
          }
        });
      } catch (error: any) {
        results.checks.push({
          name: 'HTTP访问',
          status: 'error',
          message: 'HTTP访问失败',
          error: error.message || String(error),
          details: {
            isTimeout: error.name === 'AbortError',
            isNetworkError: error.message?.includes('fetch'),
          }
        });
      }
    }

    return NextResponse.json(results);
  } catch (error) {
    console.error('[Diagnose Preview Image] Error:', error);
    return NextResponse.json(
      { 
        error: '诊断失败',
        message: error instanceof Error ? error.message : String(error)
      },
      { status: 500 }
    );
  }
}