import {Injectable} from '@angular/core';
import {JwtHelper} from 'angular2-jwt';
import { User } from '../shared/models/user';
import {ActivatedRouteSnapshot, CanActivate, RouterStateSnapshot} from '@angular/router';
import {Observable} from 'rxjs/Observable';

@Injectable()
export class SessionService implements CanActivate {

    session;
    isAuthenticated: boolean;
    jwtHelper: JwtHelper = new JwtHelper();
    user: User;

    constructor() {
        // TODO: Verify session valid
        this.exists();
    }

    /**
     * @param accessToken
     * @returns {{accessToken: *}|*|null}
     */
    create(accessToken) {
        this.session = {
            accessToken: accessToken
        };
        this.isAuthenticated = true;
        this.user = new User();
        this.decodeUserFromToken(accessToken);

        localStorage.session = this.session;
        return this.session;
    }

    destroy() {
        this.session = null;

        const subdomain = localStorage.subdomain;
        this.isAuthenticated = false;
        this.user = null;

        localStorage.clear();

        if (subdomain) {
            localStorage.subdomain = subdomain;
        }
    }

    exists() {
        const exists = typeof localStorage.session !== 'undefined' && localStorage.session !== null;
        if (exists) {
            this.isAuthenticated = true;
            console.log('User exists');
        }
        return exists;
    }

    decodeUserFromToken(token) {
        const decodedToken = this.jwtHelper.decodeToken(token);
        if (decodedToken) {
            this.setUser(decodedToken);
        }
    }

    setUser(decodedUser) {
        this.user.id = decodedUser._id;
        this.user.email = decodedUser.email;
    }

    addAuthHeaders(headers) {
        if (this.exists()) {
            headers.append('Authorization', this.session.accessToken);
        }
    }

    getUser() {
        return this.user;
    }

    getSession() {
        return localStorage.session;
    }

    getParameterByName(name) {
        name = name.replace(/[\[]/, '\\[').replace(/[\]]/, '\\]');
        const regex = new RegExp('[\\?&]' + name + '=([^&#]*)'),
            results = regex.exec(location.href);
        return results === null ? '' : decodeURIComponent(results[1].replace(/\+/g, ' '));
    }


    canActivate(route: ActivatedRouteSnapshot, state: RouterStateSnapshot): Observable<boolean> | Promise<boolean> | boolean {
        return this.isAuthenticated;
    }
}