/**
 * Error Handling Middleware
 * Centralized error handling for consistent API responses
 */

/**
 * Error handler middleware
 * Catches errors from routes and formats response
 */
function errorHandler(err, req, res, next) {
  // Log error for debugging
  console.error('Error:', err);

  // Default error response
  let statusCode = 500;
  let message = 'Internal server error';

  // Handle specific error types
  if (err.message) {
    message = err.message;

    // SQLite constraint errors
    if (err.message.includes('UNIQUE constraint')) {
      statusCode = 409; // Conflict
      message = 'A record with that value already exists';
    } else if (err.message.includes('FOREIGN KEY constraint')) {
      statusCode = 400; // Bad Request
      message = 'Invalid reference to related record';
    } else if (err.message.includes('NOT NULL constraint')) {
      statusCode = 400;
      message = 'Required field is missing';
    } else if (err.message.includes('CHECK constraint')) {
      statusCode = 400;
      message = 'Value does not meet validation requirements';
    }

    // Custom application errors
    else if (err.message.includes('not found')) {
      statusCode = 404;
    } else if (err.message.includes('Cannot delete')) {
      statusCode = 400;
    }
  }

  // Send error response
  res.status(statusCode).json({
    error: message,
    ...(process.env.NODE_ENV === 'development' && { stack: err.stack })
  });
}

/**
 * 404 Not Found handler
 * Catches requests to undefined routes
 */
function notFoundHandler(req, res) {
  res.status(404).json({
    error: 'Route not found',
    path: req.path
  });
}

module.exports = {
  errorHandler,
  notFoundHandler
};