MOBILE-3323 editor: Create offline provider for editor

src/core/editor/editor.module.ts

@@ -14,14 +14,25 @@
 
 import { NgModule } from '@angular/core';
 import { CoreEditorComponentsModule } from './components/components.module';
+import { CoreEditorOfflineProvider } from './providers/editor-offline';
+
+// List of providers (without handlers).
+export const CORE_GRADES_PROVIDERS: any[] = [
+    CoreEditorOfflineProvider,
+];
 
 @NgModule({
     declarations: [
     ],
     imports: [
-        CoreEditorComponentsModule
+        CoreEditorComponentsModule,
     ],
     providers: [
-    ]
+        CoreEditorOfflineProvider,
+    ],
 })
-export class CoreEditorModule {}
+export class CoreEditorModule {
+    constructor(editorOffline: CoreEditorOfflineProvider) {
+        // Inject the helper even if it isn't used here it's instantiated.
+    }
+}

src/core/editor/providers/editor-offline.ts

@@ -0,0 +1,254 @@
+// (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 { Injectable } from '@angular/core';
+import { CoreLoggerProvider } from '@providers/logger';
+import { CoreSitesProvider, CoreSiteSchema } from '@providers/sites';
+import { CoreTextUtilsProvider } from '@providers/utils/text';
+import { CoreUtilsProvider } from '@providers/utils/utils';
+
+/**
+ * Service with features regarding rich text editor in offline.
+ */
+@Injectable()
+export class CoreEditorOfflineProvider {
+
+    protected DRAFT_TABLE = 'editor_draft';
+
+    protected logger;
+    protected siteSchema: CoreSiteSchema = {
+        name: 'CoreEditorProvider',
+        version: 1,
+        tables: [
+            {
+                name: this.DRAFT_TABLE,
+                columns: [
+                    {
+                        name: 'contextlevel',
+                        type: 'TEXT',
+                    },
+                    {
+                        name: 'contextinstanceid',
+                        type: 'INTEGER',
+                    },
+                    {
+                        name: 'elementid',
+                        type: 'TEXT',
+                    },
+                    {
+                        name: 'extraparams', // Moodle web uses a page hash built with URL. App will use some params stringified.
+                        type: 'TEXT',
+                    },
+                    {
+                        name: 'drafttext',
+                        type: 'TEXT',
+                        notNull: true
+                    },
+                    {
+                        name: 'pageinstance',
+                        type: 'TEXT',
+                        notNull: true
+                    },
+                    {
+                        name: 'timecreated',
+                        type: 'INTEGER',
+                        notNull: true
+                    },
+                    {
+                        name: 'timemodified',
+                        type: 'INTEGER',
+                        notNull: true
+                    },
+                ],
+                primaryKeys: ['contextlevel', 'contextinstanceid', 'elementid', 'extraparams']
+            },
+        ],
+    };
+
+    constructor(
+            logger: CoreLoggerProvider,
+            protected sitesProvider: CoreSitesProvider,
+            protected textUtils: CoreTextUtilsProvider,
+            protected utils: CoreUtilsProvider) {
+        this.logger = logger.getInstance('CoreEditorProvider');
+
+        this.sitesProvider.registerSiteSchema(this.siteSchema);
+    }
+
+    /**
+     * Delete a draft from DB.
+     *
+     * @param contextLevel Context level.
+     * @param contextInstanceId The instance ID related to the context.
+     * @param elementId Element ID.
+     * @param extraParams Object with extra params to identify the draft.
+     * @param siteId Site ID. If not defined, current site.
+     * @return Promise resolved when done.
+     */
+    async deleteDraft(contextLevel: string, contextInstanceId: number, elementId: string, extraParams: {[name: string]: any},
+            siteId?: string): Promise<void> {
+
+        try {
+            const db = await this.sitesProvider.getSiteDb(siteId);
+
+            const params = this.fixDraftPrimaryData(contextLevel, contextInstanceId, elementId, extraParams);
+
+            return db.deleteRecords(this.DRAFT_TABLE, params);
+        } catch (error) {
+            // Ignore errors, probably no draft stored.
+        }
+    }
+
+    /**
+     * Return an object with the draft primary data converted to the right format.
+     *
+     * @param contextLevel Context level.
+     * @param contextInstanceId The instance ID related to the context.
+     * @param elementId Element ID.
+     * @param extraParams Object with extra params to identify the draft.
+     * @return Object with the fixed primary data.
+     */
+    protected fixDraftPrimaryData(contextLevel: string, contextInstanceId: number, elementId: string,
+            extraParams: {[name: string]: any}): CoreEditorDraftPrimaryData {
+
+        return {
+            contextlevel: contextLevel,
+            contextinstanceid: contextInstanceId,
+            elementid: elementId,
+            extraparams: this.utils.sortAndStringify(extraParams || {}),
+        };
+    }
+
+    /**
+     * Get a draft from DB.
+     *
+     * @param contextLevel Context level.
+     * @param contextInstanceId The instance ID related to the context.
+     * @param elementId Element ID.
+     * @param extraParams Object with extra params to identify the draft.
+     * @param siteId Site ID. If not defined, current site.
+     * @return Promise resolved with the draft data. Undefined if no draft stored.
+     */
+    async getDraft(contextLevel: string, contextInstanceId: number, elementId: string, extraParams: {[name: string]: any},
+            siteId?: string): Promise<CoreEditorDraft> {
+
+        const db = await this.sitesProvider.getSiteDb(siteId);
+
+        const params = this.fixDraftPrimaryData(contextLevel, contextInstanceId, elementId, extraParams);
+
+        return db.getRecord(this.DRAFT_TABLE, params);
+    }
+
+    /**
+     * Get draft to resume it.
+     *
+     * @param contextLevel Context level.
+     * @param contextInstanceId The instance ID related to the context.
+     * @param elementId Element ID.
+     * @param extraParams Object with extra params to identify the draft.
+     * @param pageInstance Unique identifier to prevent storing data from several sources at the same time.
+     * @param siteId Site ID. If not defined, current site.
+     * @return Promise resolved with the draft text. Undefined if no draft stored.
+     */
+    async resumeDraft(contextLevel: string, contextInstanceId: number, elementId: string, extraParams: {[name: string]: any},
+            pageInstance: string, siteId?: string): Promise<string> {
+
+        try {
+            // Check if there is a draft stored.
+            const entry = await this.getDraft(contextLevel, contextInstanceId, elementId, extraParams, siteId);
+
+            // There is a draft stored. Update its page instance.
+            try {
+                const db = await this.sitesProvider.getSiteDb(siteId);
+
+                entry.pageinstance = pageInstance;
+                entry.timemodified = Date.now();
+
+                await db.insertRecord(this.DRAFT_TABLE, entry);
+            } catch (error) {
+                // Ignore errors saving the draft. It shouldn't happen.
+            }
+
+            return entry.drafttext;
+        } catch (error) {
+            // No draft stored. Store an empty draft to save the pageinstance.
+            await this.saveDraft(contextLevel, contextInstanceId, elementId, extraParams, pageInstance, '', siteId);
+        }
+    }
+
+    /**
+     * Save a draft in DB.
+     *
+     * @param contextLevel Context level.
+     * @param contextInstanceId The instance ID related to the context.
+     * @param elementId Element ID.
+     * @param extraParams Object with extra params to identify the draft.
+     * @param pageInstance Unique identifier to prevent storing data from several sources at the same time.
+     * @param draftText The text to store.
+     * @param siteId Site ID. If not defined, current site.
+     * @return Promise resolved when done.
+     */
+    async saveDraft(contextLevel: string, contextInstanceId: number, elementId: string, extraParams: {[name: string]: any},
+            pageInstance: string, draftText: string, siteId?: string): Promise<void> {
+
+        let timecreated = Date.now();
+        let entry: CoreEditorDraft;
+
+        // Check if there is a draft already stored.
+        try {
+            entry = await this.getDraft(contextLevel, contextInstanceId, elementId, extraParams, siteId);
+
+            timecreated = entry.timecreated;
+        } catch (error) {
+            // No draft already stored.
+        }
+
+        if (entry && entry.pageinstance != pageInstance) {
+            this.logger.warning(`Discarding draft because of pageinstance. Context '${contextLevel}' '${contextInstanceId}', ` +
+                    `element '${elementId}'`);
+            throw null;
+        }
+
+        const db = await this.sitesProvider.getSiteDb(siteId);
+
+        const data: CoreEditorDraft = this.fixDraftPrimaryData(contextLevel, contextInstanceId, elementId, extraParams);
+
+        data.drafttext = (draftText || '').trim();
+        data.pageinstance = pageInstance;
+        data.timecreated = timecreated;
+        data.timemodified = Date.now();
+
+        await db.insertRecord(this.DRAFT_TABLE, data);
+    }
+}
+
+/**
+ * Primary data to identify a stored draft.
+ */
+type CoreEditorDraftPrimaryData = {
+    contextlevel: string; // Context level.
+    contextinstanceid: number; // The instance ID related to the context.
+    elementid: string; // Element ID.
+    extraparams: string; // Extra params stringified.
+};
+
+/**
+ * Draft data stored.
+ */
+type CoreEditorDraft = CoreEditorDraftPrimaryData & {
+    drafttext?: string; // Draft text stored.
+    pageinstance?: string; // Unique identifier to prevent storing data from several sources at the same time.
+    timecreated?: number; // Time created.
+    timemodified?: number; // Time modified.
+};