/**
 * Custom error classes and error handling utilities.
 */

/**
 * Base application error.
 */
export class AppError extends Error {
  constructor(message, statusCode = 500, code = 'INTERNAL_ERROR') {
    super(message)
    this.name = this.constructor.name
    this.statusCode = statusCode
    this.code = code
    Error.captureStackTrace(this, this.constructor)
  }
}

/**
 * Validation error (400).
 */
export class ValidationError extends AppError {
  constructor(message, details = null) {
    super(message, 400, 'VALIDATION_ERROR')
    this.details = details
  }
}

/**
 * Not found error (404).
 */
export class NotFoundError extends AppError {
  constructor(resource = 'Resource') {
    super(`${resource} not found`, 404, 'NOT_FOUND')
  }
}

/**
 * Unauthorized error (401).
 */
export class UnauthorizedError extends AppError {
  constructor(message = 'Unauthorized') {
    super(message, 401, 'UNAUTHORIZED')
  }
}

/**
 * Forbidden error (403).
 */
export class ForbiddenError extends AppError {
  constructor(message = 'Forbidden') {
    super(message, 403, 'FORBIDDEN')
  }
}

/**
 * Conflict error (409).
 */
export class ConflictError extends AppError {
  constructor(message = 'Conflict') {
    super(message, 409, 'CONFLICT')
  }
}

/**
 * Format error response for API.
 * @param {Error} error - Error object
 * @returns {object} Formatted error response
 */
export function formatErrorResponse(error) {
  if (error instanceof AppError) {
    return {
      error: {
        code: error.code,
        message: error.message,
        ...(error.details && { details: error.details }),
      },
    }
  }

  return {
    error: {
      code: 'INTERNAL_ERROR',
      message: error?.message || 'Internal server error',
    },
  }
}