MOBILE-2330 question: Implement question delegate

src/core/course/providers/default-format.ts

@@ -43,7 +43,7 @@ export class CoreCourseFormatDefaultHandler implements CoreCourseFormatHandler {
      * @param {any} course The course.
      * @return {string} Title.
      */
-    getCourseTitle?(course: any): string {
+    getCourseTitle(course: any): string {
         return course.fullname || '';
     }
 

src/core/question/providers/default-question-handler.ts

@@ -0,0 +1,134 @@
+// (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 { Injectable, Injector } from '@angular/core';
+import { CoreQuestionHandler } from './delegate';
+
+/**
+ * Default handler used when the question type doesn't have a specific implementation.
+ */
+@Injectable()
+export class CoreQuestionDefaultHandler implements CoreQuestionHandler {
+    name = 'CoreQuestionDefault';
+    type = 'default';
+
+    constructor() {
+        // Nothing to do.
+    }
+
+    /**
+     * Whether or not the handler is enabled on a site level.
+     *
+     * @return {boolean|Promise<boolean>} True or promise resolved with true if enabled.
+     */
+    isEnabled(): boolean | Promise<boolean> {
+        return true;
+    }
+
+    /**
+     * Return the Component to use to display the question.
+     * It's recommended to return the class of the component, but you can also return an instance of the component.
+     *
+     * @param {Injector} injector Injector.
+     * @param {any} question The question to render.
+     * @return {any|Promise<any>} The component (or promise resolved with component) to use, undefined if not found.
+     */
+    getComponent(injector: Injector, question: any): any | Promise<any> {
+        // There is no default component for questions.
+    }
+
+    /**
+     * Return the name of the behaviour to use for the question.
+     * If the question should use the default behaviour you shouldn't implement this function.
+     *
+     * @param {any} question The question.
+     * @param {string} behaviour The default behaviour.
+     * @return {string} The behaviour to use.
+     */
+    getBehaviour(question: any, behaviour: string): string {
+        return behaviour;
+    }
+
+    /**
+     * Check if a question can be submitted.
+     * If a question cannot be submitted it should return a message explaining why (translated or not).
+     *
+     * @param {any} question The question.
+     * @return {string} Prevent submit message. Undefined or empty if can be submitted.
+     */
+    getPreventSubmitMessage(question: any): string {
+        // Never prevent by default.
+        return '';
+    }
+
+    /**
+     * Check if a response is complete.
+     *
+     * @param {any} question The question.
+     * @param {any} answers Object with the question answers (without prefix).
+     * @return {number} 1 if complete, 0 if not complete, -1 if cannot determine.
+     */
+    isCompleteResponse(question: any, answers: any): number {
+        return -1;
+    }
+
+    /**
+     * Check if a student has provided enough of an answer for the question to be graded automatically,
+     * or whether it must be considered aborted.
+     *
+     * @param {any} question The question.
+     * @param {any} answers Object with the question answers (without prefix).
+     * @return {number} 1 if gradable, 0 if not gradable, -1 if cannot determine.
+     */
+    isGradableResponse(question: any, answers: any): number {
+        return -1;
+    }
+
+    /**
+     * Check if two responses are the same.
+     *
+     * @param {any} question Question.
+     * @param {any} prevAnswers Object with the previous question answers.
+     * @param {any} newAnswers Object with the new question answers.
+     * @return {boolean} Whether they're the same.
+     */
+    isSameResponse(question: any, prevAnswers: any, newAnswers: any): boolean {
+        return false;
+    }
+
+    /**
+     * Prepare and add to answers the data to send to server based in the input. Return promise if async.
+     *
+     * @param {any} question Question.
+     * @param {any} answers The answers retrieved from the form. Prepared answers must be stored in this object.
+     * @param {boolean} [offline] Whether the data should be saved in offline.
+     * @param {string} [siteId] Site ID. If not defined, current site.
+     * @return {void|Promise<any>} Return a promise resolved when done if async, void if sync.
+     */
+    prepareAnswers(question: any, answers: any, offline: boolean, siteId?: string): void | Promise<any> {
+        // Nothing to do.
+    }
+
+    /**
+     * Validate if an offline sequencecheck is valid compared with the online one.
+     * This function only needs to be implemented if a specific compare is required.
+     *
+     * @param {any} question The question.
+     * @param {string} offlineSequenceCheck Sequence check stored in offline.
+     * @return {boolean} Whether sequencecheck is valid.
+     */
+    validateSequenceCheck(question: any, offlineSequenceCheck: string): boolean {
+        return question.sequencecheck == offlineSequenceCheck;
+    }
+}

src/core/question/providers/delegate.ts

@@ -0,0 +1,264 @@
+// (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 { Injectable, Injector } from '@angular/core';
+import { CoreLoggerProvider } from '@providers/logger';
+import { CoreEventsProvider } from '@providers/events';
+import { CoreSitesProvider } from '@providers/sites';
+import { CoreDelegate, CoreDelegateHandler } from '@classes/delegate';
+import { CoreQuestionDefaultHandler } from './default-question-handler';
+
+/**
+ * Interface that all question type handlers must implement.
+ */
+export interface CoreQuestionHandler extends CoreDelegateHandler {
+    /**
+     * Type of the question the handler supports. E.g. 'qtype_calculated'.
+     * @type {string}
+     */
+    type: string;
+
+    /**
+     * Return the Component to use to display the question.
+     * It's recommended to return the class of the component, but you can also return an instance of the component.
+     *
+     * @param {Injector} injector Injector.
+     * @param {any} question The question to render.
+     * @return {any|Promise<any>} The component (or promise resolved with component) to use, undefined if not found.
+     */
+    getComponent(injector: Injector, question: any): any | Promise<any>;
+
+    /**
+     * Return the name of the behaviour to use for the question.
+     * If the question should use the default behaviour you shouldn't implement this function.
+     *
+     * @param {any} question The question.
+     * @param {string} behaviour The default behaviour.
+     * @return {string} The behaviour to use.
+     */
+    getBehaviour?(question: any, behaviour: string): string;
+
+    /**
+     * Check if a question can be submitted.
+     * If a question cannot be submitted it should return a message explaining why (translated or not).
+     *
+     * @param {any} question The question.
+     * @return {string} Prevent submit message. Undefined or empty if can be submitted.
+     */
+    getPreventSubmitMessage?(question: any): string;
+
+    /**
+     * Check if a response is complete.
+     *
+     * @param {any} question The question.
+     * @param {any} answers Object with the question answers (without prefix).
+     * @return {number} 1 if complete, 0 if not complete, -1 if cannot determine.
+     */
+    isCompleteResponse?(question: any, answers: any): number;
+
+    /**
+     * Check if a student has provided enough of an answer for the question to be graded automatically,
+     * or whether it must be considered aborted.
+     *
+     * @param {any} question The question.
+     * @param {any} answers Object with the question answers (without prefix).
+     * @return {number} 1 if gradable, 0 if not gradable, -1 if cannot determine.
+     */
+    isGradableResponse?(question: any, answers: any): number;
+
+    /**
+     * Check if two responses are the same.
+     *
+     * @param {any} question Question.
+     * @param {any} prevAnswers Object with the previous question answers.
+     * @param {any} newAnswers Object with the new question answers.
+     * @return {boolean} Whether they're the same.
+     */
+    isSameResponse?(question: any, prevAnswers: any, newAnswers: any): boolean;
+
+    /**
+     * Prepare and add to answers the data to send to server based in the input. Return promise if async.
+     *
+     * @param {any} question Question.
+     * @param {any} answers The answers retrieved from the form. Prepared answers must be stored in this object.
+     * @param {boolean} [offline] Whether the data should be saved in offline.
+     * @param {string} [siteId] Site ID. If not defined, current site.
+     * @return {void|Promise<any>} Return a promise resolved when done if async, void if sync.
+     */
+    prepareAnswers?(question: any, answers: any, offline: boolean, siteId?: string): void | Promise<any>;
+
+    /**
+     * Validate if an offline sequencecheck is valid compared with the online one.
+     * This function only needs to be implemented if a specific compare is required.
+     *
+     * @param {any} question The question.
+     * @param {string} offlineSequenceCheck Sequence check stored in offline.
+     * @return {boolean} Whether sequencecheck is valid.
+     */
+    validateSequenceCheck?(question: any, offlineSequenceCheck: string): boolean;
+}
+
+/**
+ * Delegate to register question handlers.
+ */
+@Injectable()
+export class CoreQuestionDelegate extends CoreDelegate {
+
+    protected handlerNameProperty = 'type';
+
+    constructor(logger: CoreLoggerProvider, sitesProvider: CoreSitesProvider, eventsProvider: CoreEventsProvider,
+            protected defaultHandler: CoreQuestionDefaultHandler) {
+        super('CoreQuestionDelegate', logger, sitesProvider, eventsProvider);
+    }
+
+    /**
+     * Get the behaviour to use for a certain question type.
+     * E.g. 'qtype_essay' uses 'manualgraded'.
+     *
+     * @param {any} question The question.
+     * @param {string} behaviour The default behaviour.
+     * @return {string} The behaviour to use.
+     */
+    getBehaviourForQuestion(question: any, behaviour: string): string {
+        const type = this.getTypeName(question),
+            questionBehaviour = this.executeFunctionOnEnabled(type, 'getBehaviour', [question, behaviour]);
+
+        return questionBehaviour || behaviour;
+    }
+
+    /**
+     * Get the directive to use for a certain question type.
+     *
+     * @param {Injector} injector Injector.
+     * @param {any} question The question to render.
+     * @return {Promise<any>} Promise resolved with component to use, undefined if not found.
+     */
+    getComponentForQuestion(injector: Injector, question: any): Promise<any> {
+        const type = this.getTypeName(question);
+
+        return Promise.resolve(this.executeFunctionOnEnabled(type, 'getComponent', [injector, question]));
+    }
+
+    /**
+     * Check if a question can be submitted.
+     * If a question cannot be submitted it should return a message explaining why (translated or not).
+     *
+     * @param {any} question Question.
+     * @return {string} Prevent submit message. Undefined or empty if can be submitted.
+     */
+    getPreventSubmitMessage(question: any): string {
+        const type = this.getTypeName(question);
+
+        return this.executeFunctionOnEnabled(type, 'getPreventSubmitMessage', [question]);
+    }
+
+    /**
+     * Given a type name, return the full name of that type. E.g. 'calculated' -> 'qtype_calculated'.
+     *
+     * @param {string} type Type to treat.
+     * @return {string} Type full name.
+     */
+    protected getFullTypeName(type: string): string {
+        return 'qtype_' + type;
+    }
+
+    /**
+     * Given a question, return the full name of its question type.
+     *
+     * @param {any} question Question.
+     * @return {string} Type name.
+     */
+    protected getTypeName(question: any): string {
+        return this.getFullTypeName(question.type);
+    }
+
+    /**
+     * Check if a response is complete.
+     *
+     * @param {any} question The question.
+     * @param {any} answers Object with the question answers (without prefix).
+     * @return {number} 1 if complete, 0 if not complete, -1 if cannot determine.
+     */
+    isCompleteResponse(question: any, answers: any): number {
+        const type = this.getTypeName(question);
+
+        return this.executeFunctionOnEnabled(type, 'isCompleteResponse', [question, answers]);
+    }
+
+    /**
+     * Check if a student has provided enough of an answer for the question to be graded automatically,
+     * or whether it must be considered aborted.
+     *
+     * @param {any} question The question.
+     * @param {any} answers Object with the question answers (without prefix).
+     * @return {number} 1 if gradable, 0 if not gradable, -1 if cannot determine.
+     */
+    isGradableResponse(question: any, answers: any): number {
+        const type = this.getTypeName(question);
+
+        return this.executeFunctionOnEnabled(type, 'isGradableResponse', [question, answers]);
+    }
+
+    /**
+     * Check if two responses are the same.
+     *
+     * @param {any} question Question.
+     * @param {any} prevAnswers Object with the previous question answers.
+     * @param {any} newAnswers Object with the new question answers.
+     * @return {boolean} Whether they're the same.
+     */
+    isSameResponse(question: any, prevAnswers: any, newAnswers: any): boolean {
+        const type = this.getTypeName(question);
+
+        return this.executeFunctionOnEnabled(type, 'isSameResponse', [question, prevAnswers, newAnswers]);
+    }
+
+    /**
+     * Check if a question type is supported.
+     *
+     * @param {string} type Question type.
+     * @return {boolean} Whether it's supported.
+     */
+    isQuestionSupported(type: string): boolean {
+        return this.hasHandler(this.getFullTypeName(type), true);
+    }
+
+    /**
+     * Prepare the answers for a certain question.
+     *
+     * @param {any} question Question.
+     * @param {any} answers The answers retrieved from the form. Prepared answers must be stored in this object.
+     * @param {boolean} [offline] Whether the data should be saved in offline.
+     * @param {string} [siteId] Site ID. If not defined, current site.
+     * @return {Promise<any>} Promise resolved when data has been prepared.
+     */
+    prepareAnswersForQuestion(question: any, answers: any, offline: boolean, siteId?: string): Promise<any> {
+        const type = this.getTypeName(question);
+
+        return Promise.resolve(this.executeFunctionOnEnabled(type, 'prepareAnswers', [question, answers, offline, siteId]));
+    }
+
+    /**
+     * Validate if an offline sequencecheck is valid compared with the online one.
+     *
+     * @param {any} question The question.
+     * @param {string} offlineSequenceCheck Sequence check stored in offline.
+     * @return {boolean} Whether sequencecheck is valid.
+     */
+    validateSequenceCheck(question: any, offlineSequenceCheck: string): boolean {
+        const type = this.getTypeName(question);
+
+        return this.executeFunctionOnEnabled(type, 'validateSequenceCheck', [question, offlineSequenceCheck]);
+    }
+}

src/core/question/question.module.ts

@@ -14,17 +14,22 @@
 
 import { NgModule } from '@angular/core';
 import { CoreQuestionProvider } from './providers/question';
+import { CoreQuestionDelegate } from './providers/delegate';
+import { CoreQuestionDefaultHandler } from './providers/default-question-handler';
 
-// List of providers.
+// List of providers (without handlers).
-export const CORE_QUESTION_PROVIDERS = [
+export const CORE_QUESTION_PROVIDERS: any[] = [
-    CoreQuestionProvider
+    CoreQuestionProvider,
+    CoreQuestionDelegate
 ];
 
 @NgModule({
     declarations: [],
     imports: [
     ],
-    providers: CORE_QUESTION_PROVIDERS,
+    providers: CORE_QUESTION_PROVIDERS.concat([
+        CoreQuestionDefaultHandler
+    ]),
     exports: []
 })
 export class CoreQuestionModule {}