import { BadRequestException, Injectable } from "@nestjs/common";
import { IsNull, Not } from "typeorm";

import { CommonMessage, LearningMessage } from "../../../common/enums/message.enum";
import { UsersService } from "../../users/providers/users.service";
import { CreateLearningCategoryDto } from "../DTO/create-learning-category.dto";
import { CreateLearningDto } from "../DTO/create-learning.dto";
import { UpdateLearningCategoryDto } from "../DTO/update-learning-category.dto";
import { UpdateLearningDto } from "../DTO/update-learning.dto";
import { LearningCategoryRepository } from "../repositories/learning-category.repository";
import { LearningProgressRepository } from "../repositories/learning-progress.repository";
import { LearningRepository } from "../repositories/learning.repository";

@Injectable()
export class LearningService {
  constructor(
    private readonly learningRepository: LearningRepository,
    private readonly learningProgressRepository: LearningProgressRepository,
    private readonly learningCategoryRepository: LearningCategoryRepository,
    private readonly usersService: UsersService,
  ) {}

  //********************************************* */

  async createLearningVideo(createDto: CreateLearningDto) {
    const { category } = await this.findCategoryById(createDto.categoryId);

    const learning = this.learningRepository.create({ ...createDto, category });
    await this.learningRepository.save(learning);

    return {
      message: CommonMessage.CREATED,
      learning,
    };
  }
  //********************************************* */

  async updateLearningVideo(learningId: string, updateDto: UpdateLearningDto) {
    const { learning } = await this.findLearningVideoById(learningId);

    if (updateDto.categoryId) {
      const { category } = await this.findCategoryById(updateDto.categoryId);
      learning.category = category;
    }

    await this.learningRepository.save({ ...learning, ...updateDto });
    return {
      message: CommonMessage.UPDATE_SUCCESS,
      learning,
    };
  }
  //********************************************* */

  async deleteLearningVideoById(learningId: string) {
    await this.findLearningVideoById(learningId);
    await this.learningRepository.softDelete(learningId);

    return {
      message: CommonMessage.DELETED,
    };
  }
  //********************************************* */

  async findLearningsVideos() {
    const learnings = await this.learningRepository.findBy({ deletedAt: IsNull() });

    return { learnings };
  }
  //********************************************* */

  async findLearningVideoById(id: string) {
    const learning = await this.learningRepository.findOneBy({ id, deletedAt: IsNull() });
    if (!learning) throw new BadRequestException(LearningMessage.NOT_FOUND);

    return { learning };
  }
  //********************************************* */

  async createLearningCategory(createDto: CreateLearningCategoryDto) {
    const existCategory = await this.learningCategoryRepository.findOneBy({ name: createDto.name });
    if (existCategory) throw new BadRequestException(LearningMessage.CATEGORY_NAME_EXIST);

    const category = this.learningCategoryRepository.create(createDto);
    await this.learningCategoryRepository.save(category);

    return { category };
  }
  //********************************************* */

  async updateLearningCategory(categoryId: string, updateDto: UpdateLearningCategoryDto) {
    const category = await this.learningCategoryRepository.findOneBy({ id: categoryId });
    if (!category) throw new BadRequestException(LearningMessage.CATEGORY_NOT_FOUND);

    if (updateDto.name) {
      const existCategory = await this.learningCategoryRepository.findOneBy({ name: updateDto.name, id: Not(categoryId) });
      if (existCategory) throw new BadRequestException(LearningMessage.CATEGORY_NAME_EXIST);
      category.name = updateDto.name;
    }

    await this.learningCategoryRepository.save({ ...category });
    return {
      message: CommonMessage.UPDATE_SUCCESS,
      category,
    };
  }
  //********************************************* */

  async deleteCategoryById(categoryId: string) {
    await this.findCategoryById(categoryId);

    await this.learningCategoryRepository.softDelete(categoryId);
    return {
      message: CommonMessage.DELETED,
    };
  }
  //********************************************* */

  async findCategories() {
    const categories = await this.learningCategoryRepository.findBy({ deletedAt: IsNull() });

    return { categories };
  }
  //********************************************* */

  async findCategoryById(id: string) {
    const category = await this.learningCategoryRepository.findOneBy({ id, deletedAt: IsNull() });
    if (!category) throw new BadRequestException(LearningMessage.CATEGORY_NOT_FOUND);

    return { category };
  }
  //********************************************* */

  async trackProgress(userId: string, learningId: string) {
    const { user } = await this.usersService.findOneById(userId);
    const { learning } = await this.findLearningVideoById(learningId);

    const progress = this.learningProgressRepository.create({ user, learning });
    return this.learningProgressRepository.save(progress);
  }
  //********************************************* */

  async getUserProgress(userId: string) {
    return this.learningProgressRepository.find({ where: { user: { id: userId } }, relations: { learning: true } });
  }
}