import { Injectable } from '@angular/core';
import {Observable} from 'rxjs';
import 'rxjs/add/operator/map';
import {AuthState, LOGIN, LOGOUT, LOGIN_SUCCESS, LOGIN_FAILURE, AuthHeaders, currentUser} from '../reducers/auth';
import {select, Store} from '@ngrx/store';
import {ApiService} from '../services/api.service';
import {LocalStorageService} from '../services/local-storage.service';

@Injectable()
export class AuthService {

  // Auth Headers
  private _authHeaders;
  get authHeaders(): AuthHeaders {
    return this._authHeaders;
  }
  set authHeaders(val: AuthHeaders) {
    this._authHeaders = val;
    // only save to local storage if headers exist
    if (val) {
      this.storage.setAuthHeaders(val);
    }
  }

  // Auth State Observable
  private _auth$: Observable<AuthState>;
  get auth$(): Observable<AuthState> { return this._auth$; }

  // Auth Store
  get store(): Store<AuthState> { return this._store; }

  constructor(private _store: Store<AuthState>, private api: ApiService, private storage: LocalStorageService) {
    this._auth$ = _store.pipe(select('auth'));
    this.auth$.subscribe((state: AuthState) => {
      this.authHeaders = state.authHeaders;
    });
  }

  login(data) {
    this.store.dispatch({ type: LOGIN });
    this.api.login(data)
      .subscribe(
        res => {
          this.login_success(res);
        },
        err => {
          this.login_failure(err.json().errors[0]);
        }
      );
  }

  validateToken(): Observable<any> {
    if (!this.authHeaders) {
      // set directly with _ so we don't save into local storage the same value again
      this._authHeaders = this.storage.getAuthHeaders();
    }
    return this.api.validateToken(this.authHeaders).map(
      res => {
        res.headers = this.authHeaders;
        this.login_success(res);
        return res;
      }
    );
  }

  logout() {
    this.api.logout(this.authHeaders)
      .subscribe(
        res => {
          this.logout_success();
        },
        err => {
          this.logout_success();
        }
      );
  }

  getLoggedInUser() {
    return this.store.pipe(select(currentUser));
  }

  private logout_success() {
    this.storage.deleteAuthHeaders();
    this.store.dispatch({ type: LOGOUT });
  }

  private login_success(res) {
    this.store.dispatch({
      type: LOGIN_SUCCESS,
      payload: {
        user: res.body.data,
        authHeaders: res.headers
      }
    });
  }

  private login_failure(error: string = 'Unknown error') {
    this.store.dispatch({ type: LOGIN_FAILURE, payload: {error: error} });
  }

}