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

import { Injectable, inject } from '@angular/core';
import {
  HttpRequest,
  HttpHandler,
  HttpEvent,
  HttpInterceptor,
  HttpErrorResponse,
  HttpClient
} from '@angular/common/http';
import { Observable, catchError, throwError, switchMap, BehaviorSubject, filter, take } from 'rxjs';
import { Router } from '@angular/router';
import { environment } from '../../environments/environment';

@Injectable()
export class AuthInterceptor implements HttpInterceptor {
  private isRefreshing = false;
  private refreshTokenSubject = new BehaviorSubject<boolean | null>(null);

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

  intercept(request: HttpRequest<unknown>, next: HttpHandler): Observable<HttpEvent<unknown>> {
    // Clone the request to add withCredentials
    const authReq = request.clone({
      withCredentials: true
    });

    return next.handle(authReq).pipe(
      catchError((error: HttpErrorResponse) => {
        if (error.status === 401 && !request.url.includes('/auth/refresh') && !request.url.includes('/auth/logout')) {
          return this.handle401Error(authReq, next);
        }
        return throwError(() => error);
      })
    );
  }

  private handle401Error(request: HttpRequest<unknown>, next: HttpHandler): Observable<HttpEvent<unknown>> {
    if (!this.isRefreshing) {
      this.isRefreshing = true;
      this.refreshTokenSubject.next(null);

      return this.http.post(
        `${environment.apiUrl}/auth/refresh`,
        {},
        { withCredentials: true }
      ).pipe(
        switchMap(() => {
          this.isRefreshing = false;
          this.refreshTokenSubject.next(true);
          return next.handle(request);
        }),
        catchError((err) => {
          this.isRefreshing = false;
          this.refreshTokenSubject.next(false);
          this.router.navigate(['/']);
          return throwError(() => err);
        })
      );
    }

    return this.refreshTokenSubject.pipe(
      filter(result => result !== null),
      take(1),
      switchMap(success => {
        if (success) {
          return next.handle(request);
        }
        return throwError(() => new Error('Token refresh failed'));
      })
    );
  }
}