import { HttpClient, HttpHeaders } from '@angular/common/http';
import { Injectable } from '@angular/core';
import { catchError, mergeMap, Observable, of, tap } from 'rxjs';
import { Pokemon } from './pokemon';

@Injectable()
export class PokemonService {
  constructor(private http: HttpClient) {}

  getPokemonList(): Observable<Pokemon[]> {
    return this.http.get<Pokemon[]>('api/pokemons').pipe(
      tap((pokemonList) => this.log(pokemonList)),
      catchError((error) => this.handleError(error, []))
    );
  }

  getPokemonById(pokemonId: number): Observable<Pokemon | undefined> {
    return this.http.get<Pokemon>(`api/pokemons/${pokemonId}`).pipe(
      tap((pokemon) => this.log(pokemon)),
      catchError((error) => this.handleError(error, undefined))
    );
  }

  getPokemonTypeList(): Observable<string[]> {
    return this.http.get<Pokemon[]>('api/pokemons').pipe(
      mergeMap((pokemons: Pokemon[]) => {
        const set = new Set<string>();
        pokemons.forEach((pokemon) =>
          pokemon.types.forEach((type) => set.add(type))
        );
        return [Array.from(set.values())];
      }),
      tap((pokemon) => this.log(pokemon)),
      catchError((error) => this.handleError(error, []))
    );
  }

  updatePokemon(pokemon: Pokemon): Observable<null> {
    const httpOptions = {
      headers: new HttpHeaders({ 'Content-Type': 'application/json' }),
    };
    return this.http.put('api/pokemons', pokemon, httpOptions).pipe(
      tap((response) => this.log(response)),
      catchError((error) => this.handleError(error, null))
    );
  }

  addPokemon(pokemon: Pokemon): Observable<Pokemon> {
    const httpOptions = {
      headers: new HttpHeaders({ 'Content-Type': 'application/json' }),
    };

    return this.http.post<Pokemon>('api/pokemons', pokemon, httpOptions).pipe(
      tap((response) => this.log(response)),
      catchError((error) => this.handleError(error, null))
    );
  }

  deletePokemonById(pokemon: Pokemon): Observable<null> {
    return this.http.delete(`api/pokemons/${pokemon.id}`).pipe(
      tap((response) => this.log(response)),
      catchError((error) => this.handleError(error, null))
    );
  }

  private log(response: any) {
    console.table(response);
  }

  private handleError(error: Error, errorValue: any) {
    console.error(error);
    return of(errorValue);
  }
}