/**
 * @copyright 2026 NHCarrigan
 * @license Naomi's Public License
 * @author Naomi Carrigan
 */

import { Injectable, signal } from '@angular/core';
import { Router } from '@angular/router';
import { Observable, tap, catchError, switchMap, throwError, of } from 'rxjs';
import { ApiService } from './api.service';
import { AuthResponse, User } from '@library/shared-types';
import { environment } from '../../environments/environment';
import { HttpClient } from '@angular/common/http';

@Injectable({
  providedIn: 'root'
})
export class AuthService {
  private currentUser = signal<User | null>(null);
  public readonly user = this.currentUser.asReadonly();
  private refreshing = false;

  constructor(
    private api: ApiService,
    private router: Router,
    private http: HttpClient
  ) {}

  login(): void {
    // Redirect to API login endpoint
    window.location.href = `${environment.apiUrl}/auth/login`;
  }

  getCurrentUser(): Observable<AuthResponse> {
    return this.api.get<AuthResponse>('/auth/me').pipe(
      tap(response => {
        this.currentUser.set(response.user);
      }),
      catchError(error => {
        if (error.status === 401) {
          return this.refreshToken().pipe(
            switchMap(() => this.api.get<AuthResponse>('/auth/me')),
            tap(response => {
              this.currentUser.set(response.user);
            }),
            catchError(() => {
              this.currentUser.set(null);
              return throwError(() => error);
            })
          );
        }
        return throwError(() => error);
      })
    );
  }

  refreshToken(): Observable<AuthResponse> {
    if (this.refreshing) {
      return of({ user: this.currentUser()!, accessToken: '' });
    }

    this.refreshing = true;
    return this.http.post<AuthResponse>(
      `${environment.apiUrl}/auth/refresh`,
      {},
      { withCredentials: true }
    ).pipe(
      tap(response => {
        this.currentUser.set(response.user);
        this.refreshing = false;
      }),
      catchError(error => {
        this.refreshing = false;
        this.currentUser.set(null);
        return throwError(() => error);
      })
    );
  }

  logout(): Observable<{ message: string }> {
    return this.api.post<{ message: string }>('/auth/logout', {}).pipe(
      tap(() => {
        this.currentUser.set(null);
        this.api.clearCsrfToken();
        this.router.navigate(['/']);
      })
    );
  }

  clearUser(): void {
    this.currentUser.set(null);
  }

  isAuthenticated(): boolean {
    return this.user() !== null;
  }

  isAdmin(): boolean {
    return this.user()?.isAdmin === true;
  }
}