import { Injectable } from '@angular/core';
import { CanActivate, ActivatedRouteSnapshot, RouterStateSnapshot, Router } from '@angular/router';

@Injectable({
  providedIn: 'root'
})
export class AuthGuard implements CanActivate {

    constructor(private router: Router) {

    }

    // 路由守卫
    canActivate(next: ActivatedRouteSnapshot, state: RouterStateSnapshot): boolean {

        return this.checkLogin();
    }

    checkLogin(): boolean {

        // 判断本地有没有token
        const token = sessionStorage.getItem('token');

        // 如果有token,允许访问
        if (token) { return true; }

        //如果没有token,跳转登录页
        this.router.navigate(['/login']);
        return false;
    }
}