import { BadRequestException, HttpStatus, Injectable } from '@nestjs/common';
import { Repository } from 'typeorm';
import { Submission } from '../entities/submission.entity';
import { InjectRepository } from '@nestjs/typeorm';
import { AnswerSubmissionDTO } from '../dtos/answer-submission.dto';
import { AppTimeoutException } from '@/common/exceptions/app-timeout.exception';
import { User } from '@/modules/users/entities/user.entity';
import { AppException } from '@/common/exceptions/app.exception';
import { RedisService } from '@/common/modules/redis/providers/redis.service';
import { isUUID } from 'class-validator';
import { GuestSubmissionSession } from '../interfaces/guest-submission-session.interfaces';
import { Question } from '@/modules/questions/entities/question.entity';
import { AppResponse } from '@/common/responses';
import { QuestionType } from '@/modules/questions/enums/question-type.enum';
import { NumericMetadata } from '@/modules/questions/interfaces/numeric-metadata.interface';
import { SubmissionAnswer } from '../entities/submission-answer.entity';
import { ChoicesService } from '@/modules/questions/providers/choices.service';
import { CalculateResultProvider } from './calculate-result.provider';
import { QuestionsService } from '@/modules/questions/providers/questions.service';
import { SubmissionResult } from '../entities/submission-result.entity';

@Injectable()
export class AnswerSubmissionProvider {
  constructor(
    /**
     * Inject Submission Repository
     */
    @InjectRepository(Submission)
    private readonly submissionRepository: Repository<Submission>,

    /**
     * Inject Redis Service
     */
    private readonly redisService: RedisService,

    /**
     * Inject SubmisionAnswer Repository
     */
    @InjectRepository(SubmissionAnswer)
    private readonly submissionAnswerRepository: Repository<SubmissionAnswer>,

    /**
     * Inject SubmissionResult Repository
     */
    @InjectRepository(SubmissionResult)
    private readonly submissionResultRepository: Repository<SubmissionResult>,

    /**
     * Inject Questions Service
     */
    private readonly questionsService: QuestionsService,

    /**
     * Inject Choices Service
     */
    private readonly choicesService: ChoicesService,

    /**
     * Inject CalculateResult Provider
     */
    private readonly calculateResultProvider: CalculateResultProvider,
  ) {}

  public async answer(
    id: string,
    answerSubmissionDto: AnswerSubmissionDTO,
    user?: User,
  ) {
    if (user) {
      return await this.answerAuthenticated(id, answerSubmissionDto, user);
    } else {
      return await this.answerGuest(id, answerSubmissionDto);
    }
  }

  private async answerAuthenticated(
    id: string,
    answerSubmissionDto: AnswerSubmissionDTO,
    user: User,
  ) {
    let submission: Submission | null = null;

    const submissionId = Number(id);

    if (Number.isNaN(submissionId)) {
      throw new AppException(
        'validation.wrongFieldFormat',
        HttpStatus.BAD_REQUEST,
        { field: '$t(submissions.fields.submissionId)' },
      );
    }

    try {
      submission = await this.submissionRepository.findOne({
        where: { id: submissionId, user: { id: user.id } },
        relations: {
          test: true,
        },
      });
    } catch (err) {
      throw new AppTimeoutException(err);
    }

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

    // if (submission.user.id !== user.id) {
    //   throw new ForbiddenException('auth.errors.accessDenied');
    // }

    // const allQuestions = [...submission.test.questions].sort(
    //   (a, b) => a.order - b.order,
    // );
    // const answeredQuestions = submission.answers.map((el) => el.question);

    // const questionStats = this.getQuestionStats(
    //   allQuestions,
    //   answeredQuestions,
    // );

    const currentQuestion: Question | null =
      await this.questionsService.findOneForAdmin({
        where: {
          test: { id: submission.test.id },
          order: submission.currentQuestionOrder,
        },
        relations: {
          choices: true,
          rangeRules: true,
        },
      });

    if (!currentQuestion) {
      let result: SubmissionResult | null;

      try {
        result = await this.submissionResultRepository.findOne({
          where: { submission: { id: submission.id } },
          relations: {
            resultRange: true,
          },
        });
      } catch (err) {
        throw new AppTimeoutException(err);
      }

      return new AppResponse({
        isCompleted: true,
        currentQuestion: null,
        result: result
          ? {
              score: result.score,
              probability: result.probability,
              title: result.resultRange?.title,
              description: result.resultRange?.description,
            }
          : null,
      });
    }

    this.checkAnswerCorrectness(currentQuestion, answerSubmissionDto);

    const submissionAnswer = this.submissionAnswerRepository.create({
      submission,
      question: currentQuestion,
    });

    if (
      currentQuestion.type === QuestionType.MULTI_CHOICE &&
      answerSubmissionDto.choiceId
    ) {
      const choice = await this.choicesService.findOneForAdmin(
        answerSubmissionDto.choiceId,
      );

      if (!choice) {
        throw new AppException(
          'validation.wrongField',
          HttpStatus.BAD_REQUEST,
          { field: '$t(submissions.fields.choiceId)' },
        );
      }

      submissionAnswer.choice = choice;
    } else if (
      currentQuestion.type === QuestionType.NUMERIC &&
      answerSubmissionDto.numericValue
    ) {
      submissionAnswer.numericValue = answerSubmissionDto.numericValue;
    }

    try {
      await this.submissionAnswerRepository.save(submissionAnswer);
    } catch (err) {
      throw new AppTimeoutException(err);
    }

    const nextQuestion: Question | null =
      await this.questionsService.findOneForAdmin({
        where: {
          test: { id: submission.test.id },
          order: submission.currentQuestionOrder + 1,
        },
        relations: {
          choices: true,
          rangeRules: true,
        },
      });

    if (!nextQuestion) {
      const result = await this.calculateResultProvider.calculate(submission);
      return new AppResponse({
        isCompleted: true,
        currentQuestion: null,
        result,
      });
    }

    return new AppResponse({
      isCompleted: false,
      // isFinal: ,
      currentQuestion: {
        type: nextQuestion.type,
        content: nextQuestion.content,
        required: nextQuestion.required,
        metadata: nextQuestion.metadata,
        choices: nextQuestion.choices,
      },
    });
  }

  private async answerGuest(
    id: string,
    answerSubmissionDto: AnswerSubmissionDTO,
  ) {
    console.log(id, answerSubmissionDto);

    if (!isUUID(id)) {
      throw new AppException(
        'validation.wrongFieldFormat',
        HttpStatus.BAD_REQUEST,
        { field: '$t(submissions.fields.submissionId)' },
      );
    }

    const submission = await this.redisService.get<GuestSubmissionSession>(
      `guest_submission:${id}`,
    );

    return submission;
  }

  private getQuestionStats(
    allQuestions: Array<Question>,
    answeredQuestions: Array<Question>,
  ) {
    const questionStats: Record<'prev' | 'current' | 'next', Question | null> =
      {
        prev: null,
        current: null,
        next: null,
      };

    if (allQuestions.length === 0) {
      return questionStats;
    }

    if (answeredQuestions.length > 0) {
      questionStats.prev = answeredQuestions[answeredQuestions.length - 1];
    }

    if (!questionStats.prev) {
      questionStats.current = allQuestions[0];
    } else {
      const prevQuestionIdx = allQuestions.findIndex(
        (val) => val.id === questionStats.prev?.id,
      );

      questionStats.current = allQuestions[prevQuestionIdx + 1];
    }

    if (questionStats.current) {
      const currentQuestionIdx = allQuestions.findIndex(
        (val) => val.id === questionStats.current?.id,
      );

      questionStats.next = allQuestions[currentQuestionIdx + 1];
    }

    return questionStats;
  }

  private checkAnswerCorrectness(
    question: Question,
    answerSubmissionDto: AnswerSubmissionDTO,
  ) {
    if (!answerSubmissionDto) throw new BadRequestException();

    const { choiceId, numericValue } = answerSubmissionDto;

    if (question.type === QuestionType.NUMERIC) {
      if (numericValue === undefined) {
        throw new BadRequestException('submissions.errors.emptyNumericValue');
      }

      const metadata = question.metadata as NumericMetadata;

      if (
        metadata &&
        (numericValue < metadata.min || numericValue > metadata.max)
      ) {
        throw new BadRequestException('submissions.errors.numericValueRange');
      }
    }

    if (question.type === QuestionType.MULTI_CHOICE) {
      if (!choiceId) {
        throw new BadRequestException('submissions.errors.emptyChoiceId');
      }

      if (!question.choices.some((c) => c.id === choiceId)) {
        throw new AppException(
          'validation.wrongField',
          HttpStatus.BAD_REQUEST,
          { field: '$t(submissions.fields.choiceId)' },
        );
      }
    }
  }
}