sandbox-science · chrisdedman · Dec 1, 2024 · Dec 1, 2024 · Dec 1, 2024
diff --git a/backend/internal/handlers/courses.go b/backend/internal/handlers/courses.go
@@ -61,7 +61,7 @@ func Course(c *fiber.Ctx) error {
 			Preload("Modules").
 			Preload("Modules.Content", func(db *gorm.DB) *gorm.DB {
 				return db.Order("id ASC")
-			  }).
+			}).
 			Preload("Tags").
 			Where("id = ?", courseID).
 			First(&course).Error; err != nil {
@@ -196,6 +196,30 @@ func CreateCourse(c *fiber.Ctx) error {
 	})
 }
 
+// Returns a true if user is enrolled in course
+func IsEnrolled(c *fiber.Ctx) error {
+	course_id := c.Params("course_id")
+	user_id := c.Params("user_id")
+
+	var count int64
+
+	if err := database.DB.Table("enrollment").Where("account_id = ? AND course_id = ?", user_id, course_id).Count(&count).Error; err != nil {
+		return c.Status(fiber.StatusNotFound).JSON(fiber.Map{"error": "Error retrieving courses"})
+	}
+
+	if count > 0 {
+		return c.JSON(fiber.Map{
+			"message": "User is enrolled in this course",
+			"isEnrolled": true,
+		})
+	} else {
+		return c.JSON(fiber.Map{
+			"message": "User is not enrolled in this course",
+			"isEnrolled": false,
+		})
+	}
+}
+
 // Enroll user into course
 func Enroll(c *fiber.Ctx) error {
 	user_id := c.Params("user_id")
@@ -223,6 +247,70 @@ func Enroll(c *fiber.Ctx) error {
 	})
 }
 
+// Uneroll user into course
+func Unenroll(c *fiber.Ctx) error {
+	user_id := c.Params("user_id")
+	course_id := c.Params("course_id")
+
+	var user entity.Account
+	// Check if the user exists
+	if err := database.DB.Where("id = ?", user_id).First(&user).Error; err != nil {
+		return c.Status(fiber.StatusNotFound).JSON(fiber.Map{"error": "User not found"})
+	}
+
+	var course entity.Course
+	// Check if the course exists
+	if err := database.DB.Where("id = ?", course_id).First(&course).Error; err != nil {
+		return c.Status(fiber.StatusNotFound).JSON(fiber.Map{"error": "Course not found"})
+	}
+
+	// Check if the user is enrolled in the course
+	if err := database.DB.Model(&user).Association("Courses").Find(&course); err != nil {
+		return c.Status(fiber.StatusNotFound).JSON(fiber.Map{"error": "User is not enrolled in this course"})
+	}
+
+	// Unenroll user into course
+	if err := database.DB.Model(&user).Association("Courses").Delete(&course); err != nil {
+		return c.Status(fiber.StatusNotFound).JSON(fiber.Map{"error": "Error unenrolling into course"})
+	}
+
+	return c.JSON(fiber.Map{
+		"message": fmt.Sprintf("Successfully unenrolled user id %d in course %s", user.ID, course.Title),
+	})
+}
+
+func CheckEnrollmentStatus(c *fiber.Ctx) error {
+	user_id := c.Params("user_id")
+	course_id := c.Params("course_id")
+
+	var user entity.Account
+	// Check if the user exists
+	if err := database.DB.Where("id = ?", user_id).First(&user).Error; err != nil {
+		return c.Status(fiber.StatusNotFound).JSON(fiber.Map{"error": "User not found"})
+	}
+
+	var course entity.Course
+	// Check if the course exists
+	if err := database.DB.Where("id = ?", course_id).First(&course).Error; err != nil {
+		return c.Status(fiber.StatusNotFound).JSON(fiber.Map{"error": "Course not found"})
+	}
+
+	// Check if the user is enrolled in the course
+	isEnrolled := false
+	if err := database.DB.Table("enrollment").
+		Where("account_id = ? AND course_id = ?", user_id, course_id).
+		Select("count(*) > 0").
+		Scan(&isEnrolled).Error; err != nil {
+		return c.Status(fiber.StatusInternalServerError).JSON(fiber.Map{"error": "Error checking enrollment status"})
+	}
+
+	// Return the enrollment status
+	return c.JSON(fiber.Map{
+		"message":    "Enrollment status checked successfully",
+		"isEnrolled": isEnrolled,
+	})
+}
+
 // Create a module inside a course
 func CreateModule(c *fiber.Ctx) error {
 	creator_id, err := strconv.Atoi(c.Params("creator_id"))
@@ -372,7 +460,7 @@ func EditContent(c *fiber.Ctx) error {
 			if err := os.Remove("./content" + path); err != nil {
 				return c.Status(fiber.StatusInternalServerError).JSON(fiber.Map{"message": err.Error()})
 			}
-		} else if !os.IsNotExist(err){
+		} else if !os.IsNotExist(err) {
 			return c.Status(fiber.StatusInternalServerError).JSON(fiber.Map{"message": err.Error()})
 		}
 
@@ -480,7 +568,7 @@ func EditThumbnail(c *fiber.Ctx) error {
 			if err := os.Remove(fmt.Sprintf("./content/%d/thumbnail.png", course_id)); err != nil {
 				return c.Status(fiber.StatusInternalServerError).JSON(fiber.Map{"message": err.Error()})
 			}
-		} else if !os.IsNotExist(err){
+		} else if !os.IsNotExist(err) {
 			return c.Status(fiber.StatusInternalServerError).JSON(fiber.Map{"message": err.Error()})
 		}
 

diff --git a/backend/internal/router/route.go b/backend/internal/router/route.go
@@ -91,5 +91,7 @@ func SetupRoutes(app *fiber.App) {
 	app.Post("/delete-file/:creator_id/:content_id", handlers.DeleteFile)
 	app.Post("/edit-content/:creator_id/:content_id", handlers.EditContent)
 	app.Post("/edit-thumbnail/:creator_id/:course_id", handlers.EditThumbnail)
+	app.Get("/is-enrolled/:user_id/:course_id", handlers.IsEnrolled)
 	app.Post("/enroll/:user_id/:course_id", handlers.Enroll)
+	app.Delete("/unenroll/:user_id/:course_id", handlers.Unenroll)
 }
diff --git a/frontend/src/components/pages/Course.js b/frontend/src/components/pages/Course.js
@@ -10,6 +10,7 @@ export function Course() {
     const [userInfo, setUserInfo]     = useState(null);
     const [error, setError]           = useState(null);
     const [file, setFile]               = useState(null);
+    const [isEnrolled, setIsEnrolled] = useState(null);
     const [newContentName, setNewContentName] = useState({
         title: "",
     });
@@ -118,6 +119,67 @@ export function Course() {
         }
     };
 
+    const handleEnroll = async () => {
+        const userId = Cookies.get('userId');
+
+        if (!userId) {
+            setError('User ID not found');
+            return;
+        }
+
+        try {
+            const response = await fetch(`http://localhost:4000/Enroll/${userId}/${courseID}`, {
+                method: "POST",
+                headers: {
+                    "Content-Type": "application/json",
+                }, 
+        });
+        const data = await response.json();
+            if (response.ok) {
+                Notiflix.Notify.success("Succesfully enrolled in the course!");
+                setTimeout(() => {
+                    window.location.reload();
+                }, 500);
+            } else {
+                Notiflix.Notify.failure(data.message || "Enrollment failed");
+            }
+        } catch (error) {
+            Notiflix.Notify.failure("Error occurred during enrollment");
+        }
+
+    };
+
+    const handleUnenroll = async () => {
+        const userId = Cookies.get('userId');
+
+        if (!userId) {
+            setError('User ID not found');
+            return;
+        }
+
+        try {
+            const response = await fetch(`http://localhost:4000/Unenroll/${userId}/${courseID}`, {
+                method: "DELETE",
+                headers: {
+                    "Content-Type": "application/json",
+                }, 
+        });
+        const data = await response.json();
+            if (response.ok) {
+                Notiflix.Notify.success("Succesfully unenrolled in the course!");
+                setTimeout(() => {
+                    window.location.reload();
+                }, 500);
+            } else {
+                Notiflix.Notify.failure(data.message || "Unenrollment failed");
+            }
+        } catch (error) {
+            Notiflix.Notify.failure("Error occurred during Unenrollment");
+        }
+
+    };
+
+
     useEffect(() => {
         const userId = Cookies.get('userId');
 
@@ -150,12 +212,25 @@ export function Course() {
             .catch((error) => setError(error.message));
         }
 
+        async function fetchIsEnrolled() {
+            await fetch(`http://localhost:4000/is-enrolled/${userId}/${courseID}`)
+            .then((response) => {
+                if (!response.ok) {
+                    throw new Error('Network response was not ok');
+                }
+                return response.json();
+            })
+            .then((data) => setIsEnrolled(data.isEnrolled))
+            .catch((error) => setError(error.message));
+        }
+
         fetchCourse();
         fetchUser();
+        fetchIsEnrolled();
     }, [courseID]);
 
     if (error) return <p>Error: {error}</p>;
-    if (!courseInfo || !userInfo) return <p>Loading...</p>;
+    if (!courseInfo || !userInfo || isEnrolled === null) return <p>Loading...</p>;
 
     var moduleList = [];
     //Push all modules into moduleList
@@ -248,6 +323,14 @@ export function Course() {
                 <div className="flex flex-1 justify-end flex-wrap gap-5 ml-20">
                     {editThumbnail}
                     {createButton}
+                    {userInfo.role === "student" && (
+                    <button
+                    onClick={isEnrolled ? handleUnenroll : handleEnroll}
+                    className={`p-2 rounded shadow text-white font-semibold ${isEnrolled ? 'bg-red-500 hover:bg-red-700' : 'bg-green-500 hover:bg-green-700'}`}
+                >
+                    {isEnrolled ? 'Unenroll from Course' : 'Enroll in Course'}
+                    </button>
+                )}
                 </div>
             </div>
             <div className="grid grid-cols-1 gap-6">