// (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, OnInit, Optional, ViewChild } from '@angular/core';
import { FormControl, FormGroup, FormBuilder, Validators } from '@angular/forms';
import { IonicPage, NavController, NavParams } from 'ionic-angular';
import { TranslateService } from '@ngx-translate/core';
import { CoreEventsProvider } from '@providers/events';
import { CoreGroupsProvider } from '@providers/groups';
import { CoreSitesProvider } from '@providers/sites';
import { CoreDomUtilsProvider } from '@providers/utils/dom';
import { CoreTimeUtilsProvider } from '@providers/utils/time';
import { CoreUtilsProvider } from '@providers/utils/utils';
import { CoreCoursesProvider } from '@core/courses/providers/courses';
import { CoreSplitViewComponent } from '@components/split-view/split-view';
import { CoreRichTextEditorComponent } from '@components/rich-text-editor/rich-text-editor.ts';
import { AddonCalendarProvider } from '../../providers/calendar';
import { AddonCalendarHelperProvider } from '../../providers/helper';
import { CoreSite } from '@classes/site';

/**
 * Page that displays a form to create/edit an event.
 */
@IonicPage({ segment: 'addon-calendar-edit-event' })
@Component({
    selector: 'page-addon-calendar-edit-event',
    templateUrl: 'edit-event.html',
})
export class AddonCalendarEditEventPage implements OnInit {

    @ViewChild(CoreRichTextEditorComponent) descriptionEditor: CoreRichTextEditorComponent;

    title: string;
    dateFormat: string;
    component = AddonCalendarProvider.COMPONENT;
    loaded = false;
    hasOffline = false;
    eventTypes = [];
    categories = [];
    courses = [];
    groups = [];
    loadingGroups = false;
    courseGroupSet = false;
    advanced = false;
    errors: any;

    // Form variables.
    eventForm: FormGroup;
    eventTypeControl: FormControl;
    groupControl: FormControl;
    descriptionControl: FormControl;

    protected eventId: number;
    protected courseId: number;
    protected originalData: any;
    protected currentSite: CoreSite;
    protected types: any; // Object with the supported types.
    protected showAll: boolean;

    constructor(navParams: NavParams,
            private navCtrl: NavController,
            private translate: TranslateService,
            private domUtils: CoreDomUtilsProvider,
            private timeUtils: CoreTimeUtilsProvider,
            private eventsProvider: CoreEventsProvider,
            private groupsProvider: CoreGroupsProvider,
            sitesProvider: CoreSitesProvider,
            private coursesProvider: CoreCoursesProvider,
            private utils: CoreUtilsProvider,
            private calendarProvider: AddonCalendarProvider,
            private calendarHelper: AddonCalendarHelperProvider,
            private fb: FormBuilder,
            @Optional() private svComponent: CoreSplitViewComponent) {

        this.eventId = navParams.get('eventId');
        this.courseId = navParams.get('courseId');
        this.title = this.eventId ? 'addon.calendar.editevent' : 'addon.calendar.newevent';

        this.currentSite = sitesProvider.getCurrentSite();
        this.errors = {
            required: this.translate.instant('core.required')
        };

        // Calculate format to use. ion-datetime doesn't support escaping characters ([]), so we remove them.
        this.dateFormat = this.timeUtils.convertPHPToMoment(this.translate.instant('core.strftimedatetimeshort'))
            .replace(/[\[\]]/g, '');

        // Initialize form variables.
        this.eventForm = new FormGroup({});
        this.eventTypeControl = this.fb.control('', Validators.required);
        this.groupControl = this.fb.control('');
        this.descriptionControl = this.fb.control('');

        this.eventForm.addControl('name', this.fb.control('', Validators.required));
        this.eventForm.addControl('timestart', this.fb.control(new Date().toISOString(), Validators.required));
        this.eventForm.addControl('eventtype', this.eventTypeControl);
        this.eventForm.addControl('categoryid', this.fb.control(''));
        this.eventForm.addControl('courseid', this.fb.control(this.courseId));
        this.eventForm.addControl('groupcourseid', this.fb.control(''));
        this.eventForm.addControl('groupid', this.groupControl);
        this.eventForm.addControl('description', this.descriptionControl);
        this.eventForm.addControl('location', this.fb.control(''));
        this.eventForm.addControl('duration', this.fb.control(0));
        this.eventForm.addControl('timedurationuntil', this.fb.control(new Date().toISOString()));
        this.eventForm.addControl('timedurationminutes', this.fb.control(''));
        this.eventForm.addControl('repeat', this.fb.control(false));
        this.eventForm.addControl('repeats', this.fb.control('1'));
    }

    /**
     * Component being initialized.
     */
    ngOnInit(): void {
        this.fetchData().finally(() => {
            this.originalData = this.utils.clone(this.eventForm.value);
            this.loaded = true;
        });
    }

    /**
     * Fetch the data needed to render the form.
     *
     * @return {Promise<any>} Promise resolved when done.
     */
    protected fetchData(): Promise<any> {
        let accessInfo;

        // Get access info.
        return this.calendarProvider.getAccessInformation().then((info) => {
            accessInfo = info;

            return this.calendarProvider.getAllowedEventTypes();
        }).then((types) => {
            this.types = types;

            const promises = [],
                eventTypes = this.calendarHelper.getEventTypeOptions(types);

            if (!eventTypes.length) {
                return Promise.reject(this.translate.instant('addon.calendar.nopermissiontoupdatecalendar'));
            }

            if (types.category) {
                // Get the categories.
                promises.push(this.coursesProvider.getCategories(0, true).then((cats) => {
                    this.categories = cats;
                }));
            }

            this.showAll = this.utils.isTrueOrOne(this.currentSite.getStoredConfig('calendar_adminseesall')) &&
                    accessInfo.canmanageentries;

            if (types.course || types.groups) {
                // Get the courses.
                const promise = this.showAll ? this.coursesProvider.getCoursesByField() : this.coursesProvider.getUserCourses();

                promises.push(promise.then((courses) => {
                    if (this.showAll) {
                        // Remove site home from the list of courses.
                        const siteHomeId = this.currentSite.getSiteHomeId();
                        courses = courses.filter((course) => {
                            return course.id != siteHomeId;
                        });
                    }

                    // Sort courses by name.
                    this.courses = courses.sort((a, b) => {
                        const compareA = a.fullname.toLowerCase(),
                            compareB = b.fullname.toLowerCase();

                        return compareA.localeCompare(compareB);
                    });
                }));
            }

            return Promise.all(promises).then(() => {
                // Set event types. If course is allowed, select it first.
                if (types.course) {
                    this.eventTypeControl.setValue(AddonCalendarProvider.TYPE_COURSE);
                } else {
                    this.eventTypeControl.setValue(eventTypes[0].value);
                }

                this.eventTypes = eventTypes;
            });

        }).catch((error) => {
            this.domUtils.showErrorModalDefault(error, 'Error getting data.');
            this.originalData = null; // Avoid asking for confirmation.
            this.navCtrl.pop();
        });
    }

    /**
     * Pull to refresh.
     *
     * @param {any} refresher Refresher.
     */
    refreshData(refresher: any): void {
        const promises = [
            this.calendarProvider.invalidateAccessInformation(this.courseId),
            this.calendarProvider.invalidateAllowedEventTypes(this.courseId)
        ];

        if (this.types) {
            if (this.types.category) {
                promises.push(this.coursesProvider.invalidateCategories(0, true));
            }
            if (this.types.course || this.types.groups) {
                if (this.showAll) {
                    promises.push(this.coursesProvider.invalidateCoursesByField());
                } else {
                    promises.push(this.coursesProvider.invalidateUserCourses());
                }
            }
        }

        Promise.all(promises).finally(() => {
            this.fetchData().finally(() => {
                refresher.complete();
            });
        });
    }

    /**
     * A course was selected, get its groups.
     *
     * @param {number} courseId Course ID.
     */
    groupCourseSelected(courseId: number): void {
        if (!courseId) {
            return;
        }

        const modal = this.domUtils.showModalLoading();
        this.loadingGroups = true;

        this.groupsProvider.getUserGroupsInCourse(courseId).then((groups) => {
            this.groups = groups;
            this.courseGroupSet = true;
            this.groupControl.setValue('');
        }).catch((error) => {
            this.domUtils.showErrorModalDefault(error, 'Error getting data.');
        }).finally(() => {
            this.loadingGroups = false;
            modal.dismiss();
        });
    }

    /**
     * Show or hide advanced form fields.
     */
    toggleAdvanced(): void {
        this.advanced = !this.advanced;
    }

    /**
     * Create the event.
     */
    submit(): void {
        // Validate data.
        const formData = this.eventForm.value,
            timeStartDate = new Date(formData.timestart),
            timeUntilDate = new Date(formData.timedurationuntil),
            timeDurationMinutes = parseInt(formData.timedurationminutes || '', 10);
        let error;

        if (formData.eventtype == AddonCalendarProvider.TYPE_COURSE && !formData.courseid) {
            error = 'core.selectacourse';
        } else if (formData.eventtype == AddonCalendarProvider.TYPE_GROUP && !formData.groupcourseid) {
            error = 'core.selectacourse';
        } else if (formData.eventtype == AddonCalendarProvider.TYPE_GROUP && !formData.groupid) {
            error = 'core.selectagroup';
        } else if (formData.eventtype == AddonCalendarProvider.TYPE_CATEGORY && !formData.categoryid) {
            error = 'core.selectacategory';
        } else if (formData.duration == 1 && timeStartDate.getTime() > timeUntilDate.getTime()) {
            error = 'addon.calendar.invalidtimedurationuntil';
        } else if (formData.duration == 2 && (isNaN(timeDurationMinutes) || timeDurationMinutes < 1)) {
            error = 'addon.calendar.invalidtimedurationminutes';
        }

        if (error) {
            // Show error and stop.
            this.domUtils.showErrorModal(this.translate.instant(error));

            return;
        }

        // Format the data to send.
        const data: any = {
            name: formData.name,
            eventtype: formData.eventtype,
            timestart: Math.floor(timeStartDate.getTime() / 1000),
            description: {
                text: formData.description,
                format: 1
            },
            location: formData.location,
            duration: formData.duration,
            repeat: formData.repeat
        };

        if (formData.eventtype == AddonCalendarProvider.TYPE_COURSE) {
            data.courseid = formData.courseid;
        } else if (formData.eventtype == AddonCalendarProvider.TYPE_GROUP) {
            data.groupcourseid = formData.groupcourseid;
            data.groupid = formData.groupid;
        } else if (formData.eventtype == AddonCalendarProvider.TYPE_CATEGORY) {
            data.categoryid = formData.categoryid;
        }

        if (formData.duration == 1) {
            data.timedurationuntil = Math.floor(timeUntilDate.getTime() / 1000);
        } else if (formData.duration == 2) {
            data.timedurationminutes = formData.timedurationminutes;
        }

        if (formData.repeat) {
            data.repeats = formData.repeats;
        }

        // Send the data.
        const modal = this.domUtils.showModalLoading('core.sending');

        this.calendarProvider.submitEvent(this.eventId, data).then((event) => {
            this.returnToList(event);
        }).catch((error) => {
            this.domUtils.showErrorModalDefault(error, 'Error sending data.');
        }).finally(() => {
            modal.dismiss();
        });
    }

    /**
     * Convenience function to update or return to event list depending on device.
     *
     * @param {number} [event] Event.
     */
    protected returnToList(event?: any): void {
        const data: any = {
            event: event
        };
        this.eventsProvider.trigger(AddonCalendarProvider.NEW_EVENT_EVENT, data, this.currentSite.getId());

        if (this.svComponent && this.svComponent.isOn()) {
            // Empty form.
            this.hasOffline = false;
            this.eventForm.reset(this.originalData);
            this.originalData = this.utils.clone(this.eventForm.value);
        } else {
            this.originalData = null; // Avoid asking for confirmation.
            this.navCtrl.pop();
        }
    }

    /**
     * Discard an offline saved discussion.
     */
    discard(): void {
        this.domUtils.showConfirm(this.translate.instant('core.areyousure')).then(() => {
            // @todo.
        }).catch(() => {
            // Cancelled.
        });
    }

    /**
     * Check if we can leave the page or not.
     *
     * @return {boolean|Promise<void>} Resolved if we can leave it, rejected if not.
     */
    ionViewCanLeave(): boolean | Promise<void> {

        if (this.calendarHelper.hasEventDataChanged(this.eventForm.value, this.originalData)) {
            // Show confirmation if some data has been modified.
            return this.domUtils.showConfirm(this.translate.instant('core.confirmcanceledit'));
        } else {
            return Promise.resolve();
        }
    }
}