import { BadRequestException, HttpStatus, Injectable } from '@nestjs/common';
import { Repository } from 'typeorm';
import { ResultRange } from '../entities/result-range.entity';
import { InjectRepository } from '@nestjs/typeorm';
import { CreateResultRangeDTO } from '../dtos/create-result-range.dto';
import { AppTimeoutException } from '@/common/exceptions/app-timeout.exception';
import { AppException } from '@/common/exceptions/app.exception';
import { TestsService } from '@/modules/tests/providers/tests.service';
import { AppResponse } from '@/common/responses';
import { I18nService } from 'nestjs-i18n';
import { UpdateResultRangeDTO } from '../dtos/update-result-range.dto';

@Injectable()
export class ResultRangeCommandProvider {
  constructor(
    /**
     * Inject ResultRange Repository
     */
    @InjectRepository(ResultRange)
    private readonly resultRangeRepository: Repository<ResultRange>,

    /**
     * Inject Tests Service
     */
    private readonly testsService: TestsService,

    /**
     * Inject I18n Service
     */
    private readonly i18nService: I18nService,
  ) {}

  private async checkRangeOverlap(
    test: number,
    minScore: number,
    maxScore: number,
    excludeSelf: boolean = false,
  ): Promise<void> {
    const queryBuilder = this.resultRangeRepository
      .createQueryBuilder('resultRange')
      .where('resultRange.testId = :test', { test })
      .andWhere(
        '(resultRange.minScore BETWEEN :minScore AND :maxScore) OR (resultRange.maxScore BETWEEN :minScore AND :maxScore) OR (:minScore BETWEEN resultRange.minScore AND resultRange.maxScore) OR (:maxScore BETWEEN resultRange.minScore AND resultRange.maxScore)',
        { minScore, maxScore },
      );

    let overlappingRanges: Array<ResultRange>;

    try {
      overlappingRanges = await queryBuilder.getMany();
    } catch (err) {
      throw new AppTimeoutException(err);
    }

    if (overlappingRanges.length > (excludeSelf ? 1 : 0)) {
      throw new AppException(
        'scoring.errors.resultRangeOverlappingConstraint',
        HttpStatus.CONFLICT,
      );
    }
  }

  private async checkResultRangeExistance(resultRangeId: number) {
    let resultRange: ResultRange | null = null;

    try {
      resultRange = await this.resultRangeRepository.findOne({
        where: {
          id: resultRangeId,
        },
        relations: {
          test: true,
        },
      });
    } catch (err) {
      throw new AppTimeoutException(err);
    }

    if (!resultRange) {
      throw new AppException(
        'common.errors.entityNotFound',
        HttpStatus.NOT_FOUND,
        { entity: '$t(scoring.fields.resultRange)' },
      );
    }

    return resultRange;
  }

  public async createOne(createResultRangeDto: CreateResultRangeDTO) {
    const test = await this.testsService.adminGetOne(createResultRangeDto.test);

    await this.checkRangeOverlap(
      test.id,
      createResultRangeDto.minScore,
      createResultRangeDto.maxScore,
    );

    const newResultRange = this.resultRangeRepository.create({
      ...createResultRangeDto,
      test,
    });

    try {
      await this.resultRangeRepository.save(newResultRange);
      return new AppResponse(
        newResultRange,
        this.i18nService.translate('common.messages.createSuccess', {
          args: { entity: '$t(scoring.fields.resultRange)' },
        }),
      );
    } catch (err) {
      throw new AppTimeoutException(err);
    }
  }

  public async updateOne(
    id: number,
    updateResultRangeDto: UpdateResultRangeDTO,
  ) {
    const resultRange = await this.checkResultRangeExistance(id);

    if (updateResultRangeDto.test) {
      await this.testsService.adminGetOne(updateResultRangeDto.test);
    }

    const testId =
      updateResultRangeDto.test !== undefined
        ? updateResultRangeDto.test
        : resultRange.test.id;

    const minScore =
      updateResultRangeDto.minScore !== undefined
        ? updateResultRangeDto.minScore
        : resultRange.minScore;

    const maxScore =
      updateResultRangeDto.maxScore !== undefined
        ? updateResultRangeDto.maxScore
        : resultRange.maxScore;

    if (minScore >= maxScore) {
      throw new BadRequestException(
        'scoring.errors.resultRangeMinMaxConstraint',
      );
    }

    await this.checkRangeOverlap(testId, minScore, maxScore, true);

    Object.assign(resultRange, updateResultRangeDto);

    try {
      return await this.resultRangeRepository.save(resultRange);
    } catch (err) {
      throw new AppTimeoutException(err);
    }
  }

  public async deleteOne(id: number) {
    const resultRange = await this.checkResultRangeExistance(id);

    try {
      await this.resultRangeRepository.delete(resultRange.id);
    } catch (err) {
      throw new AppTimeoutException(err);
    }
  }
}