import { Location } from '@angular/common';
import { Injectable } from '@angular/core';
import { Observable, of } from 'rxjs';
import { v4 as uuidv4 } from 'uuid';

export abstract class StatehandlerProcessorService {
    public abstract createState(url: string): Observable<string | undefined>;
    public abstract restoreState(state?: string): void;
}

@Injectable()
export class StatehandlerProcessorServiceImpl
    implements StatehandlerProcessorService {
    constructor(private location: Location) { }

    public createState(url: string): Observable<string> {
        const externalUrl = this.location.prepareExternalUrl(url);
        const urlId = uuidv4();

        sessionStorage.setItem(urlId, externalUrl);

        return of(urlId);
    }

    public restoreState(state?: string): void {
        if (state === undefined) {
            return;
        }

        const url = sessionStorage.getItem(state);
        if (url === null) {
            return;
        }

        window.location.href = window.location.origin + url;
    }
}