const { errorResponse } = require('../utils/apiResponse');

const errorHandler = (err, req, res, next) => {
  let statusCode = err.statusCode || res.statusCode === 200 ? 500 : res.statusCode;
  let message = err.message || 'Server Error';

  // Mongoose bad ObjectId
  if (err.name === 'CastError') {
    message = `Resource not found with id ${err.value}`;
    statusCode = 404;
  }

  // Mongoose duplicate key
  if (err.code === 11000) {
    const field = Object.keys(err.keyValue)[0];
    message = `Duplicate field value entered for ${field}. Please use another value.`;
    statusCode = 400;
  }

  // Mongoose validation error
  if (err.name === 'ValidationError') {
    message = Object.values(err.errors).map(val => val.message).join(', ');
    statusCode = 400;
  }

  console.error('[Error Handler]:', err);
  return errorResponse(res, message, err.errors || [], statusCode);
};

module.exports = errorHandler;