import { Injectable } from '@angular/core';
import { Observable, Observer, Subject } from 'rxjs';
import { Breadcrumb } from '../interfaces/breadcrumb';

@Injectable()
export class HBORBreadcrumbService {

    private breadcrumbs: Breadcrumb[];
    private prefixedBreadcrumbs: Breadcrumb[] = [];
    public breadcrumbsSource: Subject<Breadcrumb[]>;
    public breadcrumbsChanged$: Observable<Breadcrumb[]>;

    constructor() {
        this.breadcrumbs = [];
        this.breadcrumbsSource = new Subject<Breadcrumb[]>();
        this.breadcrumbsChanged$ = this.breadcrumbsSource.asObservable();

        if (localStorage.getItem('prefixedBreadcrumbs') != null) {
            this.prefixedBreadcrumbs = (JSON.parse(localStorage.getItem('prefixedBreadcrumbs')))
        }
    }

    // Store the breadcrumbs of the current route
    public store(breadcrumbs: Breadcrumb[]) {
        this.breadcrumbs = breadcrumbs;

        const allBreadcrumbs = this.prefixedBreadcrumbs.concat(this.breadcrumbs);
        this.breadcrumbsSource.next(allBreadcrumbs);

    }

    // Add a prefixed breadcrumb
    public storePrefixed(breadcrumb: Breadcrumb) {
        this.storeIfUnique(breadcrumb);
        localStorage.setItem('prefixedBreadcrumbs', JSON.stringify(this.prefixedBreadcrumbs));
        const allBreadcrumbs = this.prefixedBreadcrumbs.concat(this.breadcrumbs);
        this.breadcrumbsSource.next(allBreadcrumbs);

    }

    // Return the breadcrumbs
    public get() {
        return this.breadcrumbsChanged$
    }

    // storeIfUnique checks if there are any duplicate prefixed breadcrumbs
    private storeIfUnique(newBreadcrumb: Breadcrumb) {
        let isUnique = true;
        for (const crumb of this.prefixedBreadcrumbs) {
            if (newBreadcrumb.url === crumb.url) {
                isUnique = false;
                break;
            }
        }
        if (isUnique) {
            this.prefixedBreadcrumbs.push(newBreadcrumb);
        }
    }
}