import { validate } from 'class-validator'
import { plainToClass } from 'class-transformer'
import { Injectable, PipeTransform, ArgumentMetadata } from '@nestjs/common'
import { ValidationError } from '@app/errors/validation.error'
import { VALIDATION_ERROR_DEFAULT } from '@app/constants/text.constant'

export const isUnverifiableMetaType = (metatype: any): metatype is undefined => {
  const basicTypes = [String, Boolean, Number, Array, Object]
  return !metatype || basicTypes.includes(metatype)
}

/**
 * @class ValidationPipe
 * @classdesc validate meta type class format
 */
@Injectable()
export class ValidationPipe implements PipeTransform<any> {
  async transform(value, { metatype }: ArgumentMetadata) {
    if (isUnverifiableMetaType(metatype)) {
      return value
    }

    const object = plainToClass(metatype, value)
    const errors = await validate(object)
    if (errors.length > 0) {
      const messages: string[] = []
      const pushMessage = (constraints = {}) => {
        messages.push(...Object.values<any>(constraints))
      }

      errors.forEach((error) => {
        if (error.constraints) {
          pushMessage(error.constraints)
        }
        // MARK: keep 1 level > Maximum call stack
        if (error.children) {
          error.children.forEach((e) => pushMessage(e.constraints))
        }
      })

      throw new ValidationError(`${VALIDATION_ERROR_DEFAULT}: ` + messages.join(', '))
    }

    return object
  }
}