import { Injectable } from '@angular/core';
import { Observable } from 'rxjs/Observable';
import { tap } from 'rxjs/operators';
import { CacheApiKey } from '../models/cache-api-key.enum';
import { of } from 'rxjs';

@Injectable({
  providedIn: 'root',
})
export class ServiceCacheApi {
  private cache: Map<CacheApiKey, Observable<any>>;

  constructor() { 
    this.cache = new Map<CacheApiKey, Observable<any>>();
  }

  public get<T>(key: CacheApiKey, callToApi: Observable<T>) : Observable<T> {
    // console.log(`Get/push cache : ${CacheApiKey[key]}`);
    const cached = this.cache.get(key);

    if (cached) {
      return cached;
    } else {
      return callToApi.pipe(
                        tap(event => { 
                          this.cache.set(key, of(event));
                        }));
    }
  }

  public delete(key: CacheApiKey) {
    // console.log(`Delete cache : ${CacheApiKey[key]}`);
    this.cache.delete(key);
  }

  public getByKey<T>(key: CacheApiKey) : Observable<T> {
    // console.log(`Get cache by key : ${CacheApiKey[key]}`);
    return this.cache.get(key);
  }
}