import { HttpInterceptorFn } from '@angular/common/http';
import { inject } from '@angular/core';
import { Auth } from '@angular/fire/auth';
import { from } from 'rxjs';
import { catchError, switchMap } from 'rxjs/operators';

export const authInterceptor: HttpInterceptorFn = (req, next) => {
  const auth = inject(Auth); // Injizieren Sie den Auth-Dienst
  const token = localStorage.getItem('accessToken');

  if (token) {
    const decodedToken = decodeToken(token);
    const expirationTime = decodedToken.exp * 1000; // Umwandeln in Millisekunden
    const currentTime = Date.now();

    if (currentTime > expirationTime) {
      // Token ist abgelaufen, erneuern Sie es
      return from(refreshToken(auth)).pipe(
        switchMap(newToken => {
          const clonedReq = req.clone({
            setHeaders: {
              Authorization: `Bearer ${newToken}`,
            },
          });
          return next(clonedReq);
        }),
        catchError(error => {
          console.error('Failed to refresh token', error);
          return next(req); // Ohne Token fortfahren
        }),
      );
    } else {
      // Token ist gültig
      const clonedReq = req.clone({
        setHeaders: {
          Authorization: `Bearer ${token}`,
        },
      });
      return next(clonedReq);
    }
  } else {
    return next(req);
  }
};

async function refreshToken(auth: Auth): Promise<string> {
  return new Promise((resolve, reject) => {
    const unsubscribe = auth.onAuthStateChanged(async user => {
      if (user) {
        try {
          const newToken = await user.getIdToken(true); // Token erneuern
          localStorage.setItem('accessToken', newToken);
          resolve(newToken);
        } catch (error) {
          console.error('Failed to refresh token', error);
          reject(error);
        }
      } else {
        reject(new Error('No authenticated user found'));
      }
      unsubscribe(); // Abonnement beenden
    });
  });
}

function decodeToken(token: string): any {
  try {
    return JSON.parse(atob(token.split('.')[1]));
  } catch (e) {
    console.error('Error decoding token', e);
    return null;
  }
}