// src/utils/api.ts

// Standard JSON headers for all API responses
const JSON_HEADERS = {
  'Content-Type': 'application/json'
} as const;

/**
 * Base function to create consistent API responses
 * All other response helpers use this internally
 */
export function createAPIResponse(data: any, status: number = 200, additionalHeaders?: Record<string, string>): Response {
  const headers = additionalHeaders 
    ? { ...JSON_HEADERS, ...additionalHeaders }
    : JSON_HEADERS;
    
  return new Response(JSON.stringify(data), {
    status,
    headers
  });
}

/**
 * Success responses (2xx status codes)
 */
export const apiResponse = {
  // 200 - Success with data
  success: (data: any = { success: true }): Response => 
    createAPIResponse(data, 200),
  
  // 201 - Created (for contribution submissions, uploads, etc.)
  created: (data: any = { success: true }): Response => 
    createAPIResponse(data, 201),
    
  // 202 - Accepted (for async operations)
  accepted: (data: any = { success: true, message: 'Request accepted for processing' }): Response => 
    createAPIResponse(data, 202)
};

/**
 * Client error responses (4xx status codes)
 */
export const apiError = {
  // 400 - Bad Request
  badRequest: (message: string = 'Bad request', details?: string[]): Response => 
    createAPIResponse({ 
      success: false, 
      error: message, 
      ...(details && { details }) 
    }, 400),
  
  // 401 - Unauthorized
  unauthorized: (message: string = 'Authentication required'): Response => 
    createAPIResponse({ success: false, error: message }, 401),
  
  // 403 - Forbidden
  forbidden: (message: string = 'Access denied'): Response => 
    createAPIResponse({ success: false, error: message }, 403),
  
  // 404 - Not Found
  notFound: (message: string = 'Resource not found'): Response => 
    createAPIResponse({ success: false, error: message }, 404),
  
  // 422 - Unprocessable Entity (validation errors)
  validation: (message: string = 'Validation failed', details?: string[]): Response => 
    createAPIResponse({ 
      success: false, 
      error: message, 
      ...(details && { details }) 
    }, 422),
  
  // 429 - Rate Limited
  rateLimit: (message: string = 'Rate limit exceeded. Please wait before trying again.'): Response => 
    createAPIResponse({ success: false, error: message }, 429)
};

/**
 * Server error responses (5xx status codes)
 */
export const apiServerError = {
  // 500 - Internal Server Error
  internal: (message: string = 'Internal server error'): Response => 
    createAPIResponse({ success: false, error: message }, 500),
  
  // 502 - Bad Gateway (external service issues)
  badGateway: (message: string = 'External service error'): Response => 
    createAPIResponse({ success: false, error: message }, 502),
  
  // 503 - Service Unavailable
  unavailable: (message: string = 'Service temporarily unavailable'): Response => 
    createAPIResponse({ success: false, error: message }, 503),
  
  // 504 - Gateway Timeout
  timeout: (message: string = 'Request timeout'): Response => 
    createAPIResponse({ success: false, error: message }, 504)
};

/**
 * Specialized response helpers for common patterns
 */
export const apiSpecial = {
  // JSON parsing error
  invalidJSON: (): Response => 
    apiError.badRequest('Invalid JSON in request body'),
  
  // Missing required fields
  missingRequired: (fields: string[]): Response => 
    apiError.badRequest(`Missing required fields: ${fields.join(', ')}`),
  
  // Empty request body
  emptyBody: (): Response => 
    apiError.badRequest('Request body cannot be empty'),
  
  // File upload responses
  uploadSuccess: (data: { url: string; filename: string; size: number; storage: string }): Response => 
    apiResponse.created(data),
  
  uploadFailed: (error: string): Response => 
    apiServerError.internal(`Upload failed: ${error}`),
  
  // Contribution responses
  contributionSuccess: (data: { prUrl?: string; branchName?: string; message: string }): Response => 
    apiResponse.created({ success: true, ...data }),
  
  contributionFailed: (error: string): Response => 
    apiServerError.internal(`Contribution failed: ${error}`)
};

export const apiWithHeaders = {
  // Success with custom headers (e.g., Set-Cookie)
  successWithHeaders: (data: any, headers: Record<string, string>): Response => 
    createAPIResponse(data, 200, headers),
  
  // Redirect response
  redirect: (location: string, temporary: boolean = true): Response => 
    new Response(null, {
      status: temporary ? 302 : 301,
      headers: { 'Location': location }
    })
};

export async function handleAPIRequest<T>(
  operation: () => Promise<T>,
  errorMessage: string = 'Request processing failed'
): Promise<T | Response> {
  try {
    return await operation();
  } catch (error) {
    console.error(`API Error: ${errorMessage}:`, error);
    return apiServerError.internal(errorMessage);
  }
}

export const createAuthErrorResponse = apiError.unauthorized;
export const createBadRequestResponse = apiError.badRequest;
export const createSuccessResponse = apiResponse.success;