import {
    RouteReuseStrategy, DetachedRouteHandle, ActivatedRouteSnapshot, UrlSegment,
    ActivatedRoute, PRIMARY_OUTLET
} from '@angular/router';

export class CustomReuseStrategy implements RouteReuseStrategy {

    handlers: {[key: string]: DetachedRouteHandle} = {};

    shouldDetach(route: ActivatedRouteSnapshot): boolean {

        return !!this.getBreadcrumbs(route.root).join(".");
    }

    store(route: ActivatedRouteSnapshot, handle: DetachedRouteHandle): void {

        let url = this.getBreadcrumbs(route.root).join(".");

        this.handlers[url] = handle;
    }

    shouldAttach(route: ActivatedRouteSnapshot): boolean {

        let url = this.getBreadcrumbs(route.root).join(".");

        return !!this.handlers[url];
    }

    retrieve(route: ActivatedRouteSnapshot): DetachedRouteHandle {

        let url = this.getBreadcrumbs(route.root).join(".");

        if (!url) return null;

        return this.handlers[url];
    }

    shouldReuseRoute(future: ActivatedRouteSnapshot, curr: ActivatedRouteSnapshot): boolean {
        console.debug('CustomReuseStrategy:shouldReuseRoute', future, curr);

        return future.routeConfig === curr.routeConfig;
    }

    private getBreadcrumbs(route: ActivatedRouteSnapshot, url: string = "", breadcrumbs: string[] = []): string[] {

        //get the child routes
        let children: ActivatedRouteSnapshot[] = route.children;

        //return if there are no more children
        if (children.length === 0) {
            return breadcrumbs;
        }

        //iterate over each children
        for (let child of children) {
            //verify primary route
            if (child.outlet !== PRIMARY_OUTLET) {
                continue;
            }

            //get the route's URL segment
            let routeURL: string = child.url.map(segment => segment.path).join("/");

            //append route URL to URL
            url += `/${routeURL}`;

            breadcrumbs.push(url);

            //recursive
            return this.getBreadcrumbs(child, url, breadcrumbs);
        }

        return breadcrumbs;
    }
}