import { Injectable, OnDestroy, inject } from '@angular/core';
import { CategoryService } from '../../core/service/category.service';
import { BehaviorSubject, Observable, Subscription, map } from 'rxjs';
import { Category } from '../../core/rest-services/category/model/category';

export interface DisplayableCategory {
  id: string;
  name: string;
  subCategories: DisplayableSubCategory[];
  isOpenned: boolean;
}

export interface DisplayableSubCategory {
  id: string;
  name: string;
}

@Injectable({
  providedIn: 'root'
})
export class SideMenuService implements OnDestroy {
  private categoryService = inject(CategoryService);
  private categoriesSubject = new BehaviorSubject<DisplayableCategory[]>([]);
  private categoriesSubscription: Subscription | undefined;

  constructor() {
    this.categoriesSubscription = this.categoryService.categories$
      .pipe(
        map(categories =>
          categories
            .filter(category => category.subCategories?.length)
            .map(category => 
              this.mapToDisplayableCategory(category)
            )
        )
      )
      .subscribe(categories => this.categoriesSubject.next(categories));
  }

  ngOnDestroy(): void {
    this.categoriesSubscription?.unsubscribe();
  }

  private mapToDisplayableCategory(category: Category): DisplayableCategory {
    return {
      id: category.id,
      name: category.name,
      subCategories: category.subCategories.map(subCategory => this.mapToDisplayableSubCategory(subCategory)),
      isOpenned: false
    };
  }

  private mapToDisplayableSubCategory(subCategory: Category): DisplayableSubCategory {
    return {
      id: subCategory.id,
      name: subCategory.name
    }
  }

  get categories$(): Observable<DisplayableCategory[]> {
    return this.categoriesSubject.asObservable();
  }

  private get categories(): DisplayableCategory[] {
    return this.categoriesSubject.value;
  }

  private save(categories: DisplayableCategory[]): void {
    this.categoriesSubject.next(categories);
  }

  setOpenned(category: DisplayableCategory): void {
    const categories = this.categories;
    const matchingCategory = categories.find(categoryTemp => categoryTemp.id === category.id);
    if (matchingCategory) {
      const actualOpennedCategory = categories.find(category => category.isOpenned);
      if (actualOpennedCategory && actualOpennedCategory.id === matchingCategory.id) {
        matchingCategory.isOpenned = false;
      } else {
        categories.forEach(categoryTemp => categoryTemp.isOpenned = false);
        matchingCategory.isOpenned = true;
      }
      this.save(categories);
    }
  }
}