feat: Implement lesson creation with file uploads (video, attachments) and quiz data, integrating MinIO for storage.

Backend/src/config/minio.ts

@@ -0,0 +1,111 @@
+import { Client } from 'minio';
+import { config } from './index';
+import { logger } from './logger';
+
+/**
+ * MinIO Client Configuration
+ * Used for uploading videos and attachments to S3-compatible storage
+ */
+export const minioClient = new Client({
+    endPoint: new URL(config.s3.endpoint).hostname,
+    port: parseInt(new URL(config.s3.endpoint).port) || (config.s3.useSSL ? 443 : 9000),
+    useSSL: config.s3.useSSL,
+    accessKey: config.s3.accessKey,
+    secretKey: config.s3.secretKey,
+});
+
+/**
+ * Ensure bucket exists, create if not
+ */
+export async function ensureBucketExists(): Promise<void> {
+    try {
+        const exists = await minioClient.bucketExists(config.s3.bucket);
+        if (!exists) {
+            await minioClient.makeBucket(config.s3.bucket, 'us-east-1');
+            logger.info(`Bucket '${config.s3.bucket}' created successfully`);
+        }
+    } catch (error) {
+        logger.error(`Error ensuring bucket exists: ${error}`);
+        throw error;
+    }
+}
+
+/**
+ * Generate a unique file path for storage
+ */
+export function generateFilePath(
+    courseId: number,
+    lessonId: number,
+    fileType: 'video' | 'attachment',
+    originalFilename: string
+): string {
+    const timestamp = Date.now();
+    const uniqueId = Math.random().toString(36).substring(2, 15);
+    const extension = originalFilename.split('.').pop() || '';
+    const safeFilename = `${timestamp}-${uniqueId}.${extension}`;
+
+    if (fileType === 'video') {
+        return `courses/${courseId}/lessons/${lessonId}/video/${safeFilename}`;
+    }
+    return `courses/${courseId}/lessons/${lessonId}/attachments/${safeFilename}`;
+}
+
+/**
+ * Upload a file to MinIO
+ */
+export async function uploadFile(
+    filePath: string,
+    fileBuffer: Buffer,
+    mimeType: string
+): Promise<string> {
+    try {
+        await ensureBucketExists();
+
+        await minioClient.putObject(
+            config.s3.bucket,
+            filePath,
+            fileBuffer,
+            fileBuffer.length,
+            { 'Content-Type': mimeType }
+        );
+
+        logger.info(`File uploaded successfully: ${filePath}`);
+        return filePath;
+    } catch (error) {
+        logger.error(`Error uploading file: ${error}`);
+        throw error;
+    }
+}
+
+/**
+ * Delete a file from MinIO
+ */
+export async function deleteFile(filePath: string): Promise<void> {
+    try {
+        await minioClient.removeObject(config.s3.bucket, filePath);
+        logger.info(`File deleted successfully: ${filePath}`);
+    } catch (error) {
+        logger.error(`Error deleting file: ${error}`);
+        throw error;
+    }
+}
+
+/**
+ * Get a presigned URL for file access
+ */
+export async function getPresignedUrl(
+    filePath: string,
+    expirySeconds: number = 3600
+): Promise<string> {
+    try {
+        const url = await minioClient.presignedGetObject(
+            config.s3.bucket,
+            filePath,
+            expirySeconds
+        );
+        return url;
+    } catch (error) {
+        logger.error(`Error generating presigned URL: ${error}`);
+        throw error;
+    }
+}