feat: added numbas-lms service code

added the lms service code and functionality

Added by Daniel

src/app/api/services/numbas-lms.service.ts

@@ -0,0 +1,248 @@
+import { Injectable } from '@angular/core';
+import { HttpClient } from '@angular/common/http';
+import { BehaviorSubject, Observable, throwError } from 'rxjs';
+import { TaskService } from './task.service';
+import { UserService } from './user.service';
+import API_URL from 'src/app/config/constants/apiURL';
+
+declare let pipwerks: any;
+
+@Injectable({
+  providedIn: 'root'
+})
+export class NumbasLmsService {
+
+  private readonly apiBaseUrl = `${API_URL}/savetests`;;
+
+  private defaultValues: { [key: string]: string } = {
+    'cmi.completion_status': 'not attempted',
+    'cmi.entry': 'ab-initio',
+    'numbas.user_role': 'learner',
+    'numbas.duration_extension.units': 'seconds',
+    'cmi.mode': 'normal',
+    'cmi.undefinedlearner_response': '1',
+    'cmi.undefinedresult' : '0'
+
+  };
+
+  private testId: number = 0;
+  private taskId: number;
+  private learnerId: string;
+  initializationComplete$ = new BehaviorSubject<boolean>(false);
+
+  private scormErrors: { [key: string]: string } = {
+    "0": "No error",
+    "101": "General exception",
+  };
+
+  dataStore: { [key: string]: any } = this.getDefaultDataStore();
+
+  constructor(
+    private http: HttpClient,
+    private taskService: TaskService,
+    private userService: UserService
+) {
+    pipwerks.SCORM.version = "2004";
+    console.log(`SCORM version is set to: ${pipwerks.SCORM.version}`);
+    this.learnerId = this.userService.currentUser.studentId;
+  }
+
+  getDefaultDataStore() {
+    // Use spread operator to merge defaultValues into the dataStore
+    return {
+      ...this.defaultValues,
+      pass_status: false,
+      completed: false,
+    };
+  }
+
+  Initialize(mode: 'attempt' | 'review' = 'attempt'): string {
+    console.log('Initialize() function called');
+    const examName = 'test Exam Name 1';
+    let xhr = new XMLHttpRequest();
+    if (mode === 'review') {
+      this.SetValue('cmi.mode', 'review');
+
+      xhr.open("GET", `${this.apiBaseUrl}/completed-latest`, false);
+      xhr.send();
+      console.log(xhr.responseText);
+
+      if (xhr.status !== 200) {
+          console.error('Error fetching latest completed test result:', xhr.statusText);
+          return 'false';
+      }
+
+      try {
+          const completedTest = JSON.parse(xhr.responseText);
+          const parsedExamData = JSON.parse(completedTest.data.exam_data || '{}');
+
+          // Set entire suspendData string to cmi.suspend_data
+          this.SetValue('cmi.suspend_data', JSON.stringify(parsedExamData));
+
+          // Use SetValue to set parsedExamData values to dataStore
+          Object.keys(parsedExamData).forEach(key => {
+            this.SetValue(key, parsedExamData[key]);
+          });
+
+          this.SetValue('cmi.entry', 'RO');
+          this.SetValue('cmi.mode', 'review');
+
+          console.log('Latest completed test data:', completedTest);
+          return 'true';
+
+      } catch (error) {
+          console.error('Error:', error);
+          return 'false';
+      }
+    }
+
+    xhr.open("GET", `${this.apiBaseUrl}/latest`, false);
+    xhr.send();
+    console.log(xhr.responseText);
+
+    if (xhr.status !== 200) {
+      console.error('Error fetching latest test result:', xhr.statusText);
+      return 'false';
+    }
+
+    let latestTest;
+    try {
+        latestTest = JSON.parse(xhr.responseText);
+        console.log('Latest test result:', latestTest);
+        this.testId = latestTest.data.id;
+
+        if (latestTest.data['cmi_entry'] === 'ab-initio') {
+            console.log("starting new test");
+            this.SetValue('cmi.learner_id', this.learnerId);
+            this.dataStore['name'] = examName;
+            this.dataStore['attempt_number'] = latestTest.data['attempt_number'];
+            console.log(this.dataStore);
+      } else if (latestTest.data['cmi_entry'] === 'resume') {
+            console.log("resuming test");
+            const parsedExamData = JSON.parse(latestTest.data.exam_data || '{}');
+
+            this.dataStore = JSON.parse(JSON.stringify(parsedExamData));
+
+            console.log(this.dataStore);
+        }
+
+        this.initializationComplete$.next(true);
+
+        console.log("finished initlizing");
+        return 'true';
+    } catch (error) {
+        console.error('Error:', error);
+        return 'false';
+    }
+}
+
+
+
+  isTestCompleted(): boolean {
+    return this.dataStore?.['completed'] || false;
+  }
+
+  private resetDataStore() {
+    this.dataStore = this.getDefaultDataStore();
+  }
+
+  Terminate(): string {
+    console.log('Terminate Called');
+    const examResult = this.dataStore["cmi.score.raw"];
+    const status = this.GetValue("cmi.completion_status");
+    this.dataStore['completed'] = true;
+    const currentAttemptNumber = this.dataStore['attempt_number'] || 0;
+    const ExamName = this.dataStore['name'];
+    this.SetValue('cmi.entry', 'RO');
+    const cmientry = this.GetValue('cmi.entry');
+    const data = {
+      task_id: this.taskId,
+      name: ExamName,
+      attempt_number: currentAttemptNumber,
+      pass_status: status === 'passed',
+      exam_data: JSON.stringify(this.dataStore),
+      completed: true,
+      exam_result: examResult,
+      cmi_entry: cmientry
+    };
+
+    const xhr = new XMLHttpRequest();
+    if (this.testId) {
+      xhr.open("PUT", `${this.apiBaseUrl}/${this.testId}`, false);
+    } else {
+      xhr.open("POST", this.apiBaseUrl, false);
+    }
+    xhr.setRequestHeader("Content-Type", "application/json;charset=UTF-8");
+    xhr.send(JSON.stringify(data));
+
+    if (xhr.status !== 200) {
+      console.error('Error sending test data:', xhr.statusText);
+      return 'false';
+    }
+    this.resetDataStore();
+    return 'true';
+  }
+
+  GetValue(element: string): string {
+    return this.dataStore[element] || '';
+  }
+
+  SetValue(element: string, value: any): string {
+    if (element.startsWith('cmi.')) {
+      this.dataStore[element] = value;
+    }
+    return 'true';
+  }
+//function to save the state of the exam.
+Commit(): string {
+  if (!this.initializationComplete$.getValue()) {
+      console.warn('Initialization not complete. Cannot commit.');
+      return 'false';
+  }
+
+  // Set cmi.entry to 'resume' before committing dataStore
+  this.dataStore['cmi.entry'] = 'resume';
+  if (!this.isTestCompleted()) {
+    this.dataStore['cmi.exit'] = 'suspend';
+  }
+  console.log("Committing dataStore:", this.dataStore);
+
+  // Directly stringify the dataStore
+  const jsonData = JSON.stringify(this.dataStore);
+
+  // Use XHR to send the request
+  const xhr = new XMLHttpRequest();
+  xhr.open('PUT', `${this.apiBaseUrl}/${this.testId}/suspend`, true);
+  xhr.setRequestHeader('Content-Type', 'application/json');
+
+  xhr.onload = () => {
+      if (xhr.status >= 200 && xhr.status < 400) {
+          console.log('Suspend data saved successfully.');
+      } else {
+          console.error('Error saving suspend data:', xhr.responseText);
+      }
+  };
+
+  xhr.onerror = () => {
+      console.error('Request failed.');
+  };
+
+  xhr.send(jsonData);
+  return 'true';
+}
+
+  // Placeholder methods for SCORM error handling
+  GetLastError(): string {
+    //console.log('Get Last Error called');
+    return "0";
+  }
+
+  GetErrorString(errorCode: string): string {
+    return '';
+  }
+
+  GetDiagnostic(errorCode: string): string {
+    //console.log('Get Diagnoistic called');
+    return '';
+  }
+}