export default defineEventHandler(async (event) => {
  try {
    const requestData = await readBody(event);
    
    if (!requestData.url) {
      return {
        statusCode: 400,
        message: "URL is required",
      };
    }

    let {
      url,
      method = 'GET',
      headers = {},
      params = [],
      auth = {},
      requestBody = {},
      timeout = 30000
    } = requestData;

    // Fix URL if it doesn't have protocol
    if (!url.startsWith('http://') && !url.startsWith('https://')) {
      url = 'https://' + url;
    }

    const startTime = Date.now();

    // Build final URL with query parameters
    let urlObj;
    try {
      urlObj = new URL(url);
    } catch (error) {
      return {
        statusCode: 400,
        message: "Invalid URL format",
        data: {
          status: 400,
          statusText: 'Bad Request',
          headers: {},
          data: { error: 'Invalid URL format. Please check the URL and try again.' },
          time: 0,
          size: 0
        }
      };
    }
    
    // Add active query parameters
    params.forEach(param => {
      if (param.active && param.key && param.value) {
        urlObj.searchParams.set(param.key, param.value);
      }
    });

    // Add API key to query if specified
    if (auth.type === 'apiKey' && auth.apiKey?.key && auth.apiKey?.value && auth.apiKey?.addTo === 'query') {
      urlObj.searchParams.set(auth.apiKey.key, auth.apiKey.value);
    }

    const finalUrl = urlObj.toString();

    // Build headers
    const requestHeaders = {};
    
    // Add custom headers
    headers.forEach(header => {
      if (header.active && header.key && header.value) {
        requestHeaders[header.key] = header.value;
      }
    });

    // Add authentication headers
    if (auth.type === 'bearer' && auth.bearer) {
      requestHeaders['Authorization'] = `Bearer ${auth.bearer}`;
    } else if (auth.type === 'basic' && auth.basic?.username && auth.basic?.password) {
      const credentials = Buffer.from(`${auth.basic.username}:${auth.basic.password}`).toString('base64');
      requestHeaders['Authorization'] = `Basic ${credentials}`;
    } else if (auth.type === 'apiKey' && auth.apiKey?.key && auth.apiKey?.value && auth.apiKey?.addTo === 'header') {
      requestHeaders[auth.apiKey.key] = auth.apiKey.value;
    } else if (auth.type === 'oauth2' && auth.oauth2?.accessToken) {
      requestHeaders['Authorization'] = `${auth.oauth2.tokenType || 'Bearer'} ${auth.oauth2.accessToken}`;
    }

    // Build request body
    let requestBodyData = null;
    let contentType = null;

    if (method !== 'GET' && method !== 'HEAD' && requestBody.type && requestBody.type !== 'none') {
      if (requestBody.type === 'raw' && requestBody.raw) {
        requestBodyData = requestBody.raw;
        // Try to parse as JSON to set appropriate content type
        try {
          JSON.parse(requestBody.raw);
          contentType = 'application/json';
        } catch (e) {
          contentType = 'text/plain';
        }
      } else if (requestBody.type === 'x-www-form-urlencoded' && requestBody.urlEncoded) {
        const urlEncodedData = new URLSearchParams();
        requestBody.urlEncoded.forEach(item => {
          if (item.active && item.key && item.value) {
            urlEncodedData.append(item.key, item.value);
          }
        });
        requestBodyData = urlEncodedData.toString();
        contentType = 'application/x-www-form-urlencoded';
      } else if (requestBody.type === 'form-data' && requestBody.formData) {
        // For form-data, we'll handle files as base64 for now
        // In a real implementation, you'd want multipart/form-data support
        const formData = new URLSearchParams();
        let hasFiles = false;
        
        requestBody.formData.forEach(item => {
          if (item.active && item.key) {
            if (item.type === 'text' && item.value) {
              formData.append(item.key, item.value);
            } else if (item.type === 'file' && item.file) {
              // For now, we'll send file name as value
              // Real file upload would need special handling
              formData.append(item.key, `[FILE: ${item.file.name}]`);
              hasFiles = true;
            }
          }
        });
        
        if (hasFiles) {
          // Log a warning that file uploads aren't fully supported yet
          console.warn('File uploads in form-data are not fully supported in the backend proxy yet');
        }
        
        requestBodyData = formData.toString();
        contentType = 'application/x-www-form-urlencoded'; // Fallback to URL-encoded for now
      }
    }

    // Set content type if not already set
    if (contentType && !requestHeaders['Content-Type'] && !requestHeaders['content-type']) {
      requestHeaders['Content-Type'] = contentType;
    }

    // Create fetch options
    const fetchOptions = {
      method,
      headers: requestHeaders,
      signal: AbortSignal.timeout(timeout)
    };

    if (requestBodyData) {
      fetchOptions.body = requestBodyData;
    }

    // Make the actual HTTP request
    const response = await fetch(finalUrl, fetchOptions);
    
    const endTime = Date.now();
    const responseTime = endTime - startTime;

    // Get response data
    const responseHeaders = {};
    response.headers.forEach((value, key) => {
      responseHeaders[key] = value;
    });

    let responseData;
    const contentTypeHeader = response.headers.get('content-type') || '';
    
    if (contentTypeHeader.includes('application/json')) {
      try {
        responseData = await response.json();
      } catch (e) {
        responseData = await response.text();
      }
    } else if (contentTypeHeader.includes('text/') || contentTypeHeader.includes('application/xml')) {
      responseData = await response.text();
    } else {
      // For binary data, convert to text representation
      try {
        responseData = await response.text();
      } catch (e) {
        responseData = '[Binary data]';
      }
    }

    // Calculate response size (approximate)
    const responseSize = typeof responseData === 'string' 
      ? new Blob([responseData]).size 
      : new Blob([JSON.stringify(responseData)]).size;

    return {
      statusCode: 200,
      message: "Request completed",
      data: {
        status: response.status,
        statusText: response.statusText,
        headers: responseHeaders,
        data: responseData,
        time: responseTime,
        size: responseSize,
        url: finalUrl
      }
    };

  } catch (error) {
    console.error('API Platform Request Error:', error);
    
    const endTime = Date.now();
    
    // Handle different types of errors
    if (error.name === 'AbortError') {
      return {
        statusCode: 408,
        message: "Request timeout",
        data: {
          status: 408,
          statusText: 'Request Timeout',
          headers: {},
          data: { error: 'Request timed out' },
          time: 30000,
          size: 0
        }
      };
    }

    if (error.name === 'TypeError' && error.message.includes('fetch')) {
      return {
        statusCode: 400,
        message: "Invalid URL or network error",
        data: {
          status: 400,
          statusText: 'Bad Request',
          headers: {},
          data: { error: 'Invalid URL format or network error' },
          time: endTime - Date.now() + 1000,
          size: 0
        }
      };
    }

    if (error.code === 'ENOTFOUND' || error.code === 'ECONNREFUSED') {
      return {
        statusCode: 502,
        message: "Connection error",
        data: {
          status: 502,
          statusText: 'Bad Gateway',
          headers: {},
          data: { error: 'Failed to connect to the server' },
          time: endTime - Date.now() + 1000,
          size: 0
        }
      };
    }

    return {
      statusCode: 500,
      message: "Internal server error",
      data: {
        status: 500,
        statusText: 'Internal Server Error',
        headers: {},
        data: { error: error.message || 'Something went wrong' },
        time: endTime - Date.now() + 1000,
        size: 0
      }
    };
  }
});