NOBILE-3087 calendar: Allow navigating to all days and months in offline

src/addon/calendar/components/calendar/calendar.ts

@@ -23,6 +23,7 @@ import { AddonCalendarProvider } from '../../providers/calendar';
 import { AddonCalendarHelperProvider } from '../../providers/helper';
 import { AddonCalendarOfflineProvider } from '../../providers/calendar-offline';
 import { CoreCoursesProvider } from '@core/courses/providers/courses';
+import { CoreAppProvider } from '@providers/app';
 
 /**
  * Component that displays a calendar.
@@ -70,7 +71,8 @@ export class AddonCalendarCalendarComponent implements OnInit, OnChanges, OnDest
             private domUtils: CoreDomUtilsProvider,
             private timeUtils: CoreTimeUtilsProvider,
             private utils: CoreUtilsProvider,
-            private coursesProvider: CoreCoursesProvider) {
+            private coursesProvider: CoreCoursesProvider,
+            private appProvider: CoreAppProvider) {
 
         this.currentSiteId = sitesProvider.getCurrentSiteId();
 
@@ -184,8 +186,14 @@ export class AddonCalendarCalendarComponent implements OnInit, OnChanges, OnDest
      */
     fetchEvents(): Promise<any> {
         // Don't pass courseId and categoryId, we'll filter them locally.
-        return this.calendarProvider.getMonthlyEvents(this.year, this.month).then((result) => {
+        return this.calendarProvider.getMonthlyEvents(this.year, this.month).catch((error) => {
-
+            if (!this.appProvider.isOnline()) {
+                // Allow navigating to non-cached months in offline (behave as if using emergency cache).
+                return this.calendarHelper.getOfflineMonthWeeks(this.year, this.month);
+            } else {
+                return Promise.reject(error);
+            }
+        }).then((result) => {
             // Calculate the period name. We don't use the one in result because it's in server's language.
             this.periodName = this.timeUtils.userDate(new Date(this.year, this.month - 1).getTime(), 'core.strftimemonthyear');
 

src/addon/calendar/pages/day/day.ts

@@ -282,7 +282,14 @@ export class AddonCalendarDayPage implements OnInit, OnDestroy {
      */
     fetchEvents(): Promise<any> {
         // Don't pass courseId and categoryId, we'll filter them locally.
-        return this.calendarProvider.getDayEvents(this.year, this.month, this.day).then((result) => {
+        return this.calendarProvider.getDayEvents(this.year, this.month, this.day).catch((error) => {
+            if (!this.appProvider.isOnline()) {
+                // Allow navigating to non-cached days in offline (behave as if using emergency cache).
+                return Promise.resolve({ events: [] });
+            } else {
+                return Promise.reject(error);
+            }
+        }).then((result) => {
             const promises = [];
 
             // Calculate the period name. We don't use the one in result because it's in server's language.

src/addon/calendar/providers/calendar.ts

@@ -43,6 +43,7 @@ export class AddonCalendarProvider {
     static DEFAULT_NOTIFICATION_TIME_CHANGED = 'AddonCalendarDefaultNotificationTimeChangedEvent';
     static DEFAULT_NOTIFICATION_TIME_SETTING = 'mmaCalendarDefaultNotifTime';
     static DEFAULT_NOTIFICATION_TIME = 60;
+    static STARTING_WEEK_DAY = 'addon_calendar_starting_week_day';
     static NEW_EVENT_EVENT = 'addon_calendar_new_event';
     static NEW_EVENT_DISCARDED_EVENT = 'addon_calendar_new_event_discarded';
     static EDIT_EVENT_EVENT = 'addon_calendar_edit_event';
@@ -1198,6 +1199,11 @@ export class AddonCalendarProvider {
                     });
                 });
 
+                // Store starting week day preference, we need it in offline to show months that are not in cache.
+                if (this.appProvider.isOnline()) {
+                    this.configProvider.set(AddonCalendarProvider.STARTING_WEEK_DAY, response.daynames[0].dayno);
+                }
+
                 return response;
             });
         });

src/addon/calendar/providers/helper.ts

@@ -18,6 +18,7 @@ import { CoreSitesProvider } from '@providers/sites';
 import { CoreCourseProvider } from '@core/course/providers/course';
 import { AddonCalendarProvider } from './calendar';
 import { CoreConstants } from '@core/constants';
+import { CoreConfigProvider } from '@providers/config';
 import { CoreUtilsProvider } from '@providers/utils/utils';
 import * as moment from 'moment';
 
@@ -40,6 +41,7 @@ export class AddonCalendarHelperProvider {
             private courseProvider: CoreCourseProvider,
             private sitesProvider: CoreSitesProvider,
             private calendarProvider: AddonCalendarProvider,
+            private configProvider: CoreConfigProvider,
             private utils: CoreUtilsProvider) {
         this.logger = logger.getInstance('AddonCalendarHelperProvider');
     }
@@ -191,6 +193,66 @@ export class AddonCalendarHelperProvider {
         return year + '#' + month;
     }
 
+    /**
+     * Get weeks of a month in offline (with no events).
+     *
+     * The result has the same structure than getMonthlyEvents, but it only contains fields that are actually used by the app.
+     *
+     * @param {number} year Year to get.
+     * @param {number} month Month to get.
+     * @param {string} [siteId] Site ID. If not defined, current site.
+     * @return {Promise<any>} Promise resolved with the response.
+     */
+    getOfflineMonthWeeks(year: number, month: number, siteId?: string): Promise<any> {
+        return this.sitesProvider.getSite(siteId).then((site) => {
+            // Get starting week day user preference, fallback to site configuration.
+            const startWeekDay = site.getStoredConfig('calendar_startwday');
+
+            return this.configProvider.get(AddonCalendarProvider.STARTING_WEEK_DAY, startWeekDay);
+        }).then((startWeekDay) => {
+            const today = moment();
+            const isCurrentMonth = today.year() == year && today.month() == month - 1;
+            const weeks = [];
+
+            let date = moment({year, month: month - 1, date: 1});
+            for (let mday = 1; mday <= date.daysInMonth(); mday++) {
+                date = moment({year, month: month - 1, date: mday});
+
+                // Add new week and calculate prepadding.
+                if (!weeks.length || date.day() == startWeekDay) {
+                    const prepaddingLength = (date.day() - startWeekDay + 7) % 7;
+                    const prepadding = [];
+                    for (let i = 0; i < prepaddingLength; i++) {
+                        prepadding.push(i);
+                    }
+                    weeks.push({ prepadding, postpadding: [], days: []});
+                }
+
+                // Calculate postpadding of last week.
+                if (mday == date.daysInMonth()) {
+                    const postpaddingLength = (startWeekDay - date.day() + 6) % 7;
+                    const postpadding = [];
+                    for (let i = 0; i < postpaddingLength; i++) {
+                        postpadding.push(i);
+                    }
+                    weeks[weeks.length - 1].postpadding = postpadding;
+                }
+
+                // Add day to current week.
+                weeks[weeks.length - 1].days.push({
+                    events: [],
+                    hasevents: false,
+                    mday: date.date(),
+                    isweekend: date.day() == 0 || date.day() == 6,
+                    istoday: isCurrentMonth && today.date() == date.date(),
+                    calendareventtypes: [],
+                });
+            }
+
+            return {weeks, daynames: [{dayno: startWeekDay}]};
+        });
+    }
+
     /**
      * Check if the data of an event has changed.
      *