import { Injectable, UnprocessableEntityException } from '@nestjs/common';
import { BaseDataService } from 'src/core/modules/data/service/base-data.service';
import { validateRelations } from 'src/core/strings/constants/interface.constants';

@Injectable()
export class ValidateRelationHelper<Entity> {
  constructor(
    private dataId: string,
    private dataService: BaseDataService<Entity>,
    private relations: validateRelations[],
    private tableName: string,
  ) { }

  async execute() {
    const repository = this.dataService.getRepository();
    const queryBuilder = repository.createQueryBuilder(this.tableName);

    // load relation
    for (const relation of this.relations) {
      if (relation.singleQuery) {
        queryBuilder.leftJoinAndMapOne(
          `${ this.tableName }.${ relation.relation }`,
          `${ this.tableName }.${ relation.relation }`,
          relation.relation,
        )
      }
      else if (relation.query) {
        queryBuilder.loadRelationCountAndMap(
          `${ this.tableName }.total_${ relation.relation }`,
          `${ this.tableName }.${ relation.relation }`,
          `total_${ relation.relation }`,
          relation.query,
        );
      }
      else {
        queryBuilder.loadRelationCountAndMap(
          `${ this.tableName }.total_${ relation.relation }`,
          `${ this.tableName }.${ relation.relation }`,
          `total_${ relation.relation }`,
        );
      }
    }

    // filtering data only with specific data
    queryBuilder.where(`${ this.tableName }.id in ('${ this.dataId }')`);

    // get data
    const data = await queryBuilder.getOne();

    // process validasi
    for (const relation of this.relations) {
      const message =
        relation.message ??
        `Failed! this data already connected to ${ relation.relation }`;

      if (relation.singleQuery) {
        const relationColumn = data[relation.relation]?.[`${ relation.singleQuery[0] }`]
        if (this.mappingValidator(relationColumn, relation.singleQuery[1], relation.singleQuery[2]))
          throw new UnprocessableEntityException(message);
      } else if (data[`total_${ relation.relation } `])
        throw new UnprocessableEntityException(message);
    }
  }

  mappingValidator(column, operator, value) {
    switch (operator) {
      case '!=':
        return column != value;

      case '==':
        return column == value;

      default:
        return column == value;
    }
  }
}