import { Pipe } from '@nestjs/common';
import { ArgumentMetadata, PipeTransform } from '@nestjs/common/interfaces';
import { plainToClass } from 'class-transformer';
import { validate } from 'class-validator';
import { CustomValidationError } from '../exceptions/custom-validation.error';

@Pipe()
export class ValidationPipe implements PipeTransform<any> {
    public async transform(value, metadata: ArgumentMetadata) {
        const { metatype } = metadata;
        if (!metatype || !this.toValidate(metatype)) {
            return value;
        }
        const entity = plainToClass(metatype, value);
        const errors = await validate(entity, { validationError: { target: false } });
        if (errors.length > 0) {
            throw new CustomValidationError(errors)
        }
        return entity;
    }

    private toValidate(metatype): boolean {
        const types = [String, Boolean, Number, Array, Object];
        return !types.find(type => metatype === type) && metatype;
    }
}