import { AppException } from '@/common/exceptions/app.exception';
import { QuestionTransition } from '@/modules/questions/entities/question-transition.entity';
import { QuestionTransitionType } from '@/modules/questions/enums/question-transition-type.enum';
import { NumericCondition } from '@/modules/questions/interfaces/numeric-condition.interface';
import { SingleChoiceCondition } from '@/modules/questions/interfaces/single-choice-condition.interface';
import { TransitionValidateOptions } from '@/modules/questions/interfaces/transition-validate-options.interface';
import { HttpStatus, Injectable } from '@nestjs/common';
import { InjectRepository } from '@nestjs/typeorm';
import type { Repository } from 'typeorm';

@Injectable()
export class CheckTransitionDBProvider {
  constructor(
    /**
     * Inject Transitions Repository
     */
    @InjectRepository(QuestionTransition)
    private readonly transitionsRepository: Repository<QuestionTransition>,
  ) {}

  public async validate(
    options: TransitionValidateOptions,
    transitionId?: number,
  ) {
    await this.validateSingleStart(options, transitionId);

    await this.validateSingleEnd(options, transitionId);

    await this.validateDefaultTransition(options, transitionId);

    await this.validateDuplicateCondition(options, transitionId);
  }

  private async validateSingleStart(
    options: TransitionValidateOptions,
    transitionId?: number,
  ) {
    if (options.type !== QuestionTransitionType.START) return;

    const qb = this.transitionsRepository
      .createQueryBuilder('t')
      .where('t.testId = :testId', {
        testId: options.test.id,
      })
      .andWhere('t.type = :type', {
        type: QuestionTransitionType.START,
      });

    if (transitionId) {
      qb.andWhere('t.id != :transitionId', {
        transitionId,
      });
    }

    if (await qb.getExists()) {
      throw new AppException(
        'questions.errors.questionTransition.startAlreadyExists',
        HttpStatus.CONFLICT,
      );
    }
  }

  private async validateSingleEnd(
    options: TransitionValidateOptions,
    transitionId?: number,
  ) {
    if (options.type !== QuestionTransitionType.END) return;

    const qb = this.transitionsRepository
      .createQueryBuilder('t')
      .where('t.fromQuestionId = :fromQuestionId', {
        fromQuestionId: options.fromQuestion?.id,
      })
      .andWhere('t.type = :type', {
        type: QuestionTransitionType.END,
      });

    if (transitionId) {
      qb.andWhere('t.id != :transitionId', {
        transitionId,
      });
    }

    if (await qb.getExists()) {
      throw new AppException(
        'questions.errors.questionTransition.endAlreadyExists',
        HttpStatus.CONFLICT,
      );
    }
  }

  private async validateDefaultTransition(
    options: TransitionValidateOptions,
    transitionId?: number,
  ) {
    if (options.type !== QuestionTransitionType.DEFAULT) return;

    const qb = this.transitionsRepository
      .createQueryBuilder('t')
      .where('t.fromQuestionId = :fromQuestionId', {
        fromQuestionId: options.fromQuestion?.id,
      })
      .andWhere('t.type = :type', {
        type: QuestionTransitionType.DEFAULT,
      });

    if (transitionId) {
      qb.andWhere('t.id != :transitionId', {
        transitionId,
      });
    }

    if (await qb.getExists()) {
      throw new AppException(
        'questions.errors.questionTransition.defaultAlreadyExists',
        HttpStatus.CONFLICT,
      );
    }
  }

  private async validateDuplicateCondition(
    options: TransitionValidateOptions,
    transitionId?: number,
  ) {
    if (
      options.type === QuestionTransitionType.DEFAULT ||
      options.type === QuestionTransitionType.START ||
      options.type === QuestionTransitionType.END
    ) {
      return;
    }

    const qb = this.transitionsRepository
      .createQueryBuilder('t')
      .where('t.fromQuestionId = :fromQuestionId', {
        fromQuestionId: options.fromQuestion?.id,
      })
      .andWhere('t.type = :type', {
        type: options.type,
      });

    if (options.type === QuestionTransitionType.CHOICE) {
      qb.andWhere(`t.conditionValue ->> 'choiceId' = :choiceId`, {
        choiceId: String(
          (options.conditionValue as SingleChoiceCondition).choiceId,
        ),
      });
    }

    if (options.type === QuestionTransitionType.NUMBER_RANGE) {
      qb.andWhere(`t.conditionValue ->> 'min' = :min`, {
        min: String((options.conditionValue as NumericCondition).min),
      }).andWhere(`t.conditionValue ->> 'max' = :max`, {
        max: String((options.conditionValue as NumericCondition).max),
      });
    }

    if (transitionId) {
      qb.andWhere('t.id != :transitionId', {
        transitionId,
      });
    }

    if (await qb.getExists()) {
      throw new AppException(
        'questions.errors.questionTransition.duplicateTransition',
        HttpStatus.CONFLICT,
      );
    }
  }
}