refactor(backend): Preparation for learning content from multiple data sources.

Refactored the service layer so that it becomes possible to add another source for learning objects and learning paths.

backend/src/services/learningObjects.ts

@@ -1,134 +0,0 @@
-import { DWENGO_API_BASE } from '../config.js';
-import { fetchWithLogging } from '../util/apiHelper.js';
-import {
-    FilteredLearningObject,
-    LearningObjectMetadata,
-    LearningObjectNode,
-    LearningPathResponse,
-} from '../interfaces/learningPath.js';
-import { fetchLearningPaths } from './learningPaths.js';
-
-function filterData(
-    data: LearningObjectMetadata,
-    htmlUrl: string
-): FilteredLearningObject {
-    return {
-        key: data.hruid, // Hruid learningObject (not path)
-        _id: data._id,
-        uuid: data.uuid,
-        version: data.version,
-        title: data.title,
-        htmlUrl, // Url to fetch html content
-        language: data.language,
-        difficulty: data.difficulty,
-        estimatedTime: data.estimated_time,
-        available: data.available,
-        teacherExclusive: data.teacher_exclusive,
-        educationalGoals: data.educational_goals, // List with learningObjects
-        keywords: data.keywords, // For search
-        description: data.description, // For search (not an actual description)
-        targetAges: data.target_ages,
-        contentType: data.content_type, // Markdown, image, audio, etc.
-        contentLocation: data.content_location, // If content type extern
-        skosConcepts: data.skos_concepts,
-        returnValue: data.return_value, // Callback response information
-    };
-}
-
-/**
- * Fetches a single learning object by its HRUID
- */
-export async function getLearningObjectById(
-    hruid: string,
-    language: string
-): Promise<FilteredLearningObject | null> {
-    const metadataUrl = `${DWENGO_API_BASE}/learningObject/getMetadata?hruid=${hruid}&language=${language}`;
-    const metadata = await fetchWithLogging<LearningObjectMetadata>(
-        metadataUrl,
-        `Metadata for Learning Object HRUID "${hruid}" (language ${language})`
-    );
-
-    if (!metadata) {
-        console.error(`⚠️ WARNING: Learning object "${hruid}" not found.`);
-        return null;
-    }
-
-    const htmlUrl = `${DWENGO_API_BASE}/learningObject/getRaw?hruid=${hruid}&language=${language}`;
-    return filterData(metadata, htmlUrl);
-}
-
-/**
- * Generic function to fetch learning objects (full data or just HRUIDs)
- */
-async function fetchLearningObjects(
-    hruid: string,
-    full: boolean,
-    language: string
-): Promise<FilteredLearningObject[] | string[]> {
-    try {
-        const learningPathResponse: LearningPathResponse =
-            await fetchLearningPaths(
-                [hruid],
-                language,
-                `Learning path for HRUID "${hruid}"`
-            );
-
-        if (
-            !learningPathResponse.success ||
-            !learningPathResponse.data?.length
-        ) {
-            console.error(
-                `⚠️ WARNING: Learning path "${hruid}" exists but contains no learning objects.`
-            );
-            return [];
-        }
-
-        const nodes: LearningObjectNode[] = learningPathResponse.data[0].nodes;
-
-        if (!full) {
-            return nodes.map((node) => {
-                return node.learningobject_hruid;
-            });
-        }
-
-        return await Promise.all(
-            nodes.map(async (node) => {
-                return getLearningObjectById(
-                    node.learningobject_hruid,
-                    language
-                );
-            })
-        ).then((objects) => {
-            return objects.filter((obj): obj is FilteredLearningObject => {
-                return obj !== null;
-            });
-        });
-    } catch (error) {
-        console.error('❌ Error fetching learning objects:', error);
-        return [];
-    }
-}
-
-/**
- * Fetch full learning object data (metadata)
- */
-export async function getLearningObjectsFromPath(
-    hruid: string,
-    language: string
-): Promise<FilteredLearningObject[]> {
-    return (await fetchLearningObjects(
-        hruid,
-        true,
-        language
-    )) as FilteredLearningObject[];
-}
-
-/**
- * Fetch only learning object HRUIDs
- */
-export async function getLearningObjectIdsFromPath(
-    hruid: string,
-    language: string
-): Promise<string[]> {
-    return (await fetchLearningObjects(hruid, false, language)) as string[];
-}