// (C) Copyright 2015 Moodle Pty Ltd.
//
// 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, ViewChild, Input, OnInit } from '@angular/core';
import { Content } from 'ionic-angular';
import { CoreUserProvider } from '../../providers/user';
import { CoreDomUtilsProvider } from '@providers/utils/dom';
import { CoreSplitViewComponent } from '@components/split-view/split-view';
import { CoreAppProvider } from '@providers/app';

/**
 * Component that displays the list of course participants.
 */
@Component({
    selector: 'core-user-participants',
    templateUrl: 'core-user-participants.html',
})
export class CoreUserParticipantsComponent implements OnInit {
    @ViewChild(Content) content: Content;
    @ViewChild(CoreSplitViewComponent) splitviewCtrl: CoreSplitViewComponent;

    @Input() courseId: number;

    participantId: number;
    participants = [];
    canLoadMore = false;
    loadMoreError = false;
    participantsLoaded = false;
    canSearch = false;
    showSearchBox = false;
    disableSearch = false;
    displaySearchResults = false;
    searchQuery = '';

    protected searchPage = 0;

    constructor(private userProvider: CoreUserProvider,
            private domUtils: CoreDomUtilsProvider,
            private appProvider: CoreAppProvider) { }

    /**
     * View loaded.
     */
    ngOnInit(): void {
        this.canSearch = this.userProvider.canSearchParticipantsInSite();

        // Get first participants.
        this.fetchData(true).then(() => {
            if (!this.participantId && this.splitviewCtrl.isOn() && this.participants.length > 0) {
                // Take first and load it.
                this.gotoParticipant(this.participants[0].id);
            }
            // Add log in Moodle.
            this.userProvider.logParticipantsView(this.courseId).catch(() => {
                // Ignore errors.
            });
        }).finally(() => {
            // Call resize to make infinite loading work, in some cases the content dimensions aren't read.
            this.content && this.content.resize();
        });
    }

    /**
     * Fetch all the data required for the view.
     *
     * @param refresh Empty events array first.
     * @return Resolved when done.
     */
    fetchData(refresh: boolean = false): Promise<any> {
        const firstToGet = refresh ? 0 : this.participants.length;
        this.loadMoreError = false;

        return this.userProvider.getParticipants(this.courseId, firstToGet).then((data) => {
            if (refresh) {
                this.participants = data.participants;
            } else {
                this.participants = this.participants.concat(data.participants);
            }
            this.canLoadMore = data.canLoadMore;
        }).catch((error) => {
            this.domUtils.showErrorModalDefault(error, 'Error loading participants');
            this.loadMoreError = true; // Set to prevent infinite calls with infinite-loading.
        }).finally(() => {
            this.participantsLoaded = true;
        });
    }

    /**
     * Function to load more data.
     *
     * @param infiniteComplete Infinite scroll complete function. Only used from core-infinite-loading.
     * @return Resolved when done.
     */
    loadMoreData(infiniteComplete?: any): Promise<any> {
        if (this.displaySearchResults) {
            return this.search(this.searchQuery, true).finally(() => {
                infiniteComplete && infiniteComplete();
            });
        } else {
            return this.fetchData().finally(() => {
                infiniteComplete && infiniteComplete();
            });
        }
    }

    /**
     * Refresh data.
     *
     * @param refresher Refresher.
     */
    refreshParticipants(refresher: any): void {
        this.userProvider.invalidateParticipantsList(this.courseId).finally(() => {
            this.fetchData(true).finally(() => {
                refresher.complete();
            });
        });
    }

    /**
     * Navigate to a particular user profile.
     *
     * @param userId User Id where to navigate.
     */
    gotoParticipant(userId: number): void {
        this.participantId = userId;
        this.splitviewCtrl.push('CoreUserProfilePage', {userId: userId, courseId: this.courseId});
    }

    /**
     * Show or hide search box.
     */
    toggleSearch(): void {
        this.showSearchBox = !this.showSearchBox;

        if (!this.showSearchBox && this.displaySearchResults) {
            this.clearSearch();
        }
    }

    /**
     * Clear search.
     */
    clearSearch(): void {
        if (!this.displaySearchResults) {
            // Nothing to clear.
            return;
        }

        this.searchQuery = '';
        this.displaySearchResults = false;
        this.participants = [];
        this.searchPage = 0;
        this.splitviewCtrl.emptyDetails();

        // Remove search results and display all participants.
        this.participantsLoaded = false;
        this.fetchData(true);
    }

    /**
     * Start a new search or load more results.
     *
     * @param query Text to search for.
     * @param loadMore Whether it's loading more or doing a new search.
     * @return Resolved when done.
     */
    search(query: string, loadMore?: boolean): Promise<any> {
        this.appProvider.closeKeyboard();

        this.disableSearch = true;
        this.participantsLoaded = loadMore;
        this.loadMoreError = false;

        if (!loadMore) {
            this.participantsLoaded = false;
            this.searchQuery = query;
            this.searchPage = 0;
            this.participants = [];
        }

        return this.userProvider.searchParticipants(this.courseId, query, true, this.searchPage).then((result) => {

            this.participants.push(...result.participants);
            this.canLoadMore = result.canLoadMore;
            this.searchPage++;

            if (!loadMore && this.participants.length) {
                this.gotoParticipant(this.participants[0].id);
            }
        }).catch((error) => {
            this.domUtils.showErrorModalDefault(error, 'Error searching users.');
            this.loadMoreError = true;

        }).finally(() => {
            this.disableSearch = false;
            this.participantsLoaded = true;
            this.displaySearchResults = true;
        });
    }
}