// (C) Copyright 2015 Martin Dougiamas
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

import { Component, OnDestroy, ViewChild } from '@angular/core';
import { IonicPage, NavController, NavParams } from 'ionic-angular';
import { CoreSitesProvider } from '@providers/sites';
import { CoreEventsProvider } from '@providers/events';
import { CoreIonTabsComponent } from '@components/ion-tabs/ion-tabs';
import { CoreMainMenuProvider } from '../../providers/mainmenu';
import { CoreMainMenuDelegate, CoreMainMenuHandlerToDisplay } from '../../providers/delegate';

/**
 * Page that displays the main menu of the app.
 */
@IonicPage({segment: 'core-mainmenu'})
@Component({
    selector: 'page-core-mainmenu',
    templateUrl: 'menu.html',
})
export class CoreMainMenuPage implements OnDestroy {
    tabs: CoreMainMenuHandlerToDisplay[] = [];
    loaded = false;
    redirectPage: string;
    redirectParams: any;
    showTabs = false;

    protected subscription;
    protected redirectObs: any;
    protected pendingRedirect: any;

    @ViewChild('mainTabs') mainTabs: CoreIonTabsComponent;

    constructor(private menuDelegate: CoreMainMenuDelegate, private sitesProvider: CoreSitesProvider, navParams: NavParams,
            private navCtrl: NavController, private eventsProvider: CoreEventsProvider) {

        // Check if the menu was loaded with a redirect.
        const redirectPage = navParams.get('redirectPage');
        if (redirectPage) {
            this.pendingRedirect = {
                redirectPage: redirectPage,
                redirectParams: navParams.get('redirectParams')
            };
        }
    }

    /**
     * View loaded.
     */
    ionViewDidLoad(): void {
        if (!this.sitesProvider.isLoggedIn()) {
            this.navCtrl.setRoot('CoreLoginInitPage');

            return;
        }

        this.showTabs = true;

        this.redirectObs = this.eventsProvider.on(CoreEventsProvider.LOAD_PAGE_MAIN_MENU, (data) => {
            if (!this.loaded) {
                // View isn't ready yet, wait for it to be ready.
                this.pendingRedirect = data;
            } else {
                delete this.pendingRedirect;
                this.handleRedirect(data);
            }
        });

        this.subscription = this.menuDelegate.getHandlers().subscribe((handlers) => {
            // Remove the handlers that should only appear in the More menu.
            handlers = handlers.filter((handler) => {
                return !handler.onlyInMore;
            });
            handlers = handlers.slice(0, CoreMainMenuProvider.NUM_MAIN_HANDLERS); // Get main handlers.

            // Re-build the list of tabs. If a handler is already in the list, use existing object to prevent re-creating the tab.
            const newTabs = [];

            for (let i = 0; i < handlers.length; i++) {
                const handler = handlers[i];

                // Check if the handler is already in the tabs list. If so, use it.
                const tab = this.tabs.find((tab) => {
                    return tab.title == handler.title && tab.icon == handler.icon;
                });

                newTabs.push(tab || handler);
            }

            this.tabs = newTabs;

            // Sort them by priority so new handlers are in the right position.
            this.tabs.sort((a, b) => {
                return b.priority - a.priority;
            });

            this.loaded = this.menuDelegate.areHandlersLoaded();

            if (this.loaded && this.pendingRedirect) {
                // Wait for tabs to be initialized and then handle the redirect.
                setTimeout(() => {
                    if (this.pendingRedirect) {
                        this.handleRedirect(this.pendingRedirect);
                        delete this.pendingRedirect;
                    }
                });
            }
        });
    }

    /**
     * Handle a redirect.
     *
     * @param {any} data Data received.
     */
    protected handleRedirect(data: any): void {
        // Check if the redirect page is the root page of any of the tabs.
        const i = this.tabs.findIndex((tab, i) => {
            return tab.page == data.redirectPage;
        });

        if (i >= 0) {
            // Tab found. Set the params.
            this.tabs[i].pageParams = Object.assign({}, data.redirectParams);
        } else {
            // Tab not found, use a phantom tab.
            this.redirectPage = data.redirectPage;
            this.redirectParams = data.redirectParams;
        }

        setTimeout(() => {
            // Let the tab load the params before navigating.
            this.mainTabs.selectTabRootByIndex(i + 1);
        });
    }

    /**
     * Page destroyed.
     */
    ngOnDestroy(): void {
        this.subscription && this.subscription.unsubscribe();
        this.redirectObs && this.redirectObs.off();
    }
}