const fs = require('fs');
const path = require('path');

class ApiDebugLogger {
  constructor() {
    this.logFile = path.join(__dirname, '..', '..', 'api_debug.log');
    this.enabled = process.env.NODE_ENV === 'development' || process.env.API_DEBUG === 'true';
    
    // Debug logging setup
    if (this.enabled) {
      console.log(`🐛 ApiDebugLogger: Enabled (NODE_ENV=${process.env.NODE_ENV}, API_DEBUG=${process.env.API_DEBUG})`);
      console.log(`🐛 ApiDebugLogger: Log file path: ${this.logFile}`);
      
      // Ensure the log file exists
      try {
        if (!fs.existsSync(this.logFile)) {
          fs.writeFileSync(this.logFile, `# API Debug Log Started at ${new Date().toISOString()}\n`);
          console.log(`🐛 ApiDebugLogger: Created log file at ${this.logFile}`);
        }
      } catch (error) {
        console.error(`❌ ApiDebugLogger: Failed to create log file: ${error}`);
      }
    } else {
      console.log(`🐛 ApiDebugLogger: Disabled (NODE_ENV=${process.env.NODE_ENV}, API_DEBUG=${process.env.API_DEBUG})`);
    }
  }

  log(method, url, statusCode, requestBody = {}, responseBody = {}, headers = {}) {
    if (!this.enabled) return;

    const timestamp = new Date().toISOString();
    const sanitizedRequest = this.sanitizeData(requestBody);
    const sanitizedResponse = this.sanitizeData(responseBody);
    const sanitizedHeaders = this.sanitizeHeaders(headers);

    const logEntry = [
      `[${timestamp}]`,
      method.toUpperCase(),
      url,
      `-`,
      `STATUS:${statusCode}`,
      `-`,
      `REQ:${JSON.stringify(sanitizedRequest)}`,
      `-`,
      `RES:${JSON.stringify(sanitizedResponse)}`,
      `-`,
      `HEADERS:${JSON.stringify(sanitizedHeaders)}`
    ].join(' ');

    try {
      fs.appendFileSync(this.logFile, logEntry + '\n');
      console.log(`🐛 API Log: ${method.toUpperCase()} ${url} - ${statusCode}`);
    } catch (error) {
      console.error('❌ Failed to write to API debug log:', error);
    }
  }

  sanitizeData(data) {
    if (!data || typeof data !== 'object') return data;

    const sanitized = { ...data };
    
    // Remove sensitive fields
    const sensitiveFields = ['password', 'token', 'secret', 'key', 'auth', 'authorization'];
    
    sensitiveFields.forEach(field => {
      if (sanitized[field]) {
        sanitized[field] = '***REDACTED***';
      }
    });

    return sanitized;
  }

  sanitizeHeaders(headers) {
    if (!headers || typeof headers !== 'object') return {};

    const sanitized = { ...headers };
    
    // Remove sensitive headers
    const sensitiveHeaders = ['authorization', 'cookie', 'x-api-key', 'x-auth-token'];
    
    sensitiveHeaders.forEach(header => {
      if (sanitized[header]) {
        sanitized[header] = '***REDACTED***';
      }
    });

    return sanitized;
  }

  logRequest(req) {
    if (!this.enabled) return;

    const timestamp = new Date().toISOString();
    const logEntry = `[${timestamp}] INCOMING ${req.method} ${req.url} - BODY:${JSON.stringify(this.sanitizeData(req.body))} - HEADERS:${JSON.stringify(this.sanitizeHeaders(req.headers))}`;
    
    try {
      fs.appendFileSync(this.logFile, logEntry + '\n');
      console.log(`🐛 API Request: ${req.method} ${req.url}`);
    } catch (error) {
      console.error('❌ Failed to write request to API debug log:', error);
    }
  }

  logResponse(req, res, responseBody) {
    if (!this.enabled) return;

    this.log(
      req.method,
      req.url,
      res.statusCode,
      req.body,
      responseBody,
      {
        'content-type': res.getHeader('content-type'),
        'user-agent': req.headers['user-agent']
      }
    );
  }

  clear() {
    try {
      fs.writeFileSync(this.logFile, '# API Debug Log Cleared at ' + new Date().toISOString() + '\n');
      console.log('API debug log cleared');
    } catch (error) {
      console.error('Failed to clear API debug log:', error);
    }
  }
}

// Middleware function for Express
function apiDebugMiddleware(req, res, next) {
  const logger = new ApiDebugLogger();
  
  // Log incoming request
  logger.logRequest(req);
  
  // Override res.json to capture response
  const originalJson = res.json;
  res.json = function(data) {
    logger.logResponse(req, res, data);
    return originalJson.call(this, data);
  };
  
  next();
}

module.exports = {
  ApiDebugLogger,
  apiDebugMiddleware
};