import {Inject, Injectable, PLATFORM_ID} from '@angular/core';
import {HttpClient} from '@angular/common/http';
import {Observable} from 'rxjs';
import {environment} from "../../environments/environment";
import {isPlatformBrowser} from "@angular/common";
import {jwtDecode, JwtPayload} from "jwt-decode";

@Injectable({
  providedIn: 'root'
})
export class AuthService {

  private readonly authUrl: string

  constructor(private http: HttpClient,
              @Inject(PLATFORM_ID) private platformId: Object) {
    this.authUrl = `${environment.backendUrl}/api/auth`;
  }

  private get isBrowser(): boolean {
    return isPlatformBrowser(this.platformId);
  }

  isLoggedIn(): boolean {
    if (!this.isBrowser) return false;
    return localStorage.getItem("app.token") != null;
  }

  login(username: string, password: string): Observable<string> {
    if (!this.isBrowser) {
      throw new Error('Login can only be performed in browser');
    }

    const credentials = btoa(`${username}:${password}`);

    const httpOptions = {
      headers: {
        'Authorization': `Basic ${credentials}`,
        'Content-Type': 'application/json'
      },
      responseType: 'text' as 'text',
    };
    return this.http.post(this.authUrl, null, httpOptions);
  }

  logout() {
    if (!this.isBrowser) return;
    localStorage.removeItem("app.token");
    localStorage.removeItem("app.roles");
  }

  isUserInRole(roleFromRoute: string) {
    if (!this.isBrowser) return false;

    const roles = localStorage.getItem("app.roles");

    if (roles!.includes(",")) {
      if (roles === roleFromRoute) {
        return true;
      }
    } else {
      const roleArray = roles!.split(",");
      for (let role of roleArray) {
        if (role === roleFromRoute) {
          return true;
        }
      }
    }
    return false;
  }

  getUsername(): string | null {
    if (!this.isBrowser) return null;

    const token = localStorage.getItem("app.token");
    if (!token) return null;

    try {
      const decodedToken = jwtDecode<JwtPayload>(token);
      return decodedToken.sub || null;  // 'sub' is the standard JWT claim for subject/username
    } catch (error) {
      return null;
    }
  }
}