add classroom name check

backend/internal/handlers/classrooms/classrooms.go

@@ -2,9 +2,11 @@ package classrooms
 
 import (
 	"context"
+	"errors"
 	"fmt"
 	"log"
 	"net/http"
+	"net/url"
 	"strconv"
 	"strings"
 	"time"
@@ -48,6 +50,28 @@ func (s *ClassroomService) getClassroom() fiber.Handler {
 	}
 }
 
+func (s *ClassroomService) checkClassroomExists() fiber.Handler {
+	return func(c *fiber.Ctx) error {
+		classroomName := c.Params("classroom_name")
+		if classroomName == "" {
+			return errs.BadRequest(errors.New("classroom name is required"))
+		}
+
+		// Decode the URL-encoded classroom name
+		decodedName, err := url.QueryUnescape(classroomName)
+		if err != nil {
+			return errs.BadRequest(errors.New("invalid classroom name encoding"))
+		}
+
+		_, err = s.store.GetClassroomByName(c.Context(), decodedName)
+		exists := err == nil // If no error, classroom exists
+
+		return c.Status(http.StatusOK).JSON(fiber.Map{
+			"exists": exists,
+		})
+	}
+}
+
 // Creates a new classroom.
 func (s *ClassroomService) createClassroom() fiber.Handler {
 	return func(c *fiber.Ctx) error {
@@ -62,6 +86,15 @@ func (s *ClassroomService) createClassroom() fiber.Handler {
 			return errs.InvalidRequestBody(models.Classroom{})
 		}
 
+		// check if classroom exists already
+		_, err = s.store.GetClassroomByName(c.Context(), classroomData.Name)
+		exists := err == nil // If no error, classroom exists
+		if exists {
+			return c.Status(http.StatusConflict).JSON(fiber.Map{
+				"exists": true,
+			})
+		}
+
 		membership, err := client.GetUserOrgMembership(c.Context(), classroomData.OrgName, githubUser.Login)
 		if err != nil || *membership.Role != "admin" {
 			return errs.InsufficientPermissionsError()

backend/internal/handlers/classrooms/routes.go

@@ -40,6 +40,9 @@ func classroomRoutes(router fiber.Router, service *ClassroomService) fiber.Route
 	// Create a classroom
 	classroomRouter.Post("/", service.createClassroom())
 
+	// Check if a classroom exists
+	classroomRouter.Get("/check-classroom/:classroom_name", service.checkClassroomExists())
+
 	// Update a classroom
 	classroomRouter.Put("/classroom/:classroom_id", service.updateClassroom())
 

backend/internal/storage/postgres/classrooms.go

@@ -76,6 +76,27 @@ func (db *DB) GetClassroomByID(ctx context.Context, classroomID int64) (models.C
 	return classroomData, nil
 }
 
+func (db *DB) GetClassroomByName(ctx context.Context, classroomName string) (models.Classroom, error) {
+	var classroomData models.Classroom
+	err := db.connPool.QueryRow(ctx, `
+	SELECT id, name, org_id, org_name, created_at, student_team_name
+	FROM classrooms
+	WHERE name = $1`, classroomName).Scan(
+		&classroomData.ID,
+		&classroomData.Name,
+		&classroomData.OrgID,
+		&classroomData.OrgName,
+		&classroomData.CreatedAt,
+		&classroomData.StudentTeamName,
+	)
+
+	if err != nil {
+		return models.Classroom{}, errs.NewDBError(err)
+	}
+
+	return classroomData, nil
+}
+
 func (db *DB) AddUserToClassroom(ctx context.Context, classroomID int64, classroomRole string, classroomStatus models.UserStatus, userID int64) (models.ClassroomUser, error) {
 	var classroomUser models.ClassroomUser
 

backend/internal/storage/storage.go

@@ -49,6 +49,7 @@ type Classroom interface {
 	CreateClassroom(ctx context.Context, classroomData models.Classroom) (models.Classroom, error)
 	UpdateClassroom(ctx context.Context, classroomData models.Classroom) (models.Classroom, error)
 	GetClassroomByID(ctx context.Context, classroomID int64) (models.Classroom, error)
+	GetClassroomByName(ctx context.Context, classroomName string) (models.Classroom, error)
 	AddUserToClassroom(ctx context.Context, classroomID int64, classroomRole string, classroomStatus models.UserStatus, userID int64) (models.ClassroomUser, error)
 	RemoveUserFromClassroom(ctx context.Context, classroomID int64, userID int64) error
 	ModifyUserRole(ctx context.Context, classroomID int64, classroomRole string, userID int64) (models.ClassroomUser, error)

frontend/src/api/classrooms.ts

@@ -245,3 +245,19 @@ export async function getClassroomNames(): Promise<string[]> {
   const resp: { semester_names: string[] } = await response.json();
   return resp.semester_names;
 }
+
+export async function checkClassroomExists(classroomName: string): Promise<boolean> {
+  const encodedName = encodeURIComponent(classroomName);
+  const response = await fetch(`${base_url}/classrooms/check-classroom/${encodedName}`, {
+    method: "GET",
+    credentials: "include",
+    headers: {
+      "Content-Type": "application/json",
+    },
+  });
+  if (!response.ok) {
+    throw new Error(response.statusText);
+  }
+  const data = await response.json();
+  return data.exists;
+}

frontend/src/global.css

@@ -105,6 +105,13 @@ a {
  font-size: var(--body-font-size);
 }
 
+.error {
+  color: var(--red);
+  font-size: var(--font-size-xs);
+  margin-top: 5px;
+  text-align: center;
+}
+
 /* Custom scroll bar flex properties and styling */
 .simplebar-wrapper {
   flex-grow: 1;

frontend/src/pages/Classrooms/Create/index.tsx

@@ -1,6 +1,6 @@
 import React, { useContext, useEffect, useState } from "react";
 import { useNavigate, Link } from "react-router-dom";
-import { getClassroomNames, postClassroom } from "@/api/classrooms";
+import { checkClassroomExists, getClassroomNames, postClassroom } from "@/api/classrooms";
 import { SelectedClassroomContext } from "@/contexts/selectedClassroom";
 import { getOrganizationDetails } from "@/api/organizations";
 import useUrlParameter from "@/hooks/useUrlParameter";
@@ -22,6 +22,23 @@ const ClassroomCreation: React.FC = () => {
   const { setSelectedClassroom } = useContext(SelectedClassroomContext);
   const navigate = useNavigate();
 
+  const [classroomExists, setClassroomExists] = useState(false);
+
+  useEffect(() => {
+    const checkExists = async () => {
+      if (name) {
+        const exists = await checkClassroomExists(name);
+        setClassroomExists(exists);
+        if (exists) {
+          setError("A classroom with this name already exists.");
+        } else {
+          setError(null);
+        }
+      }
+    };
+    checkExists();
+  }, [name]);
+
   useEffect(() => {
     const fetchClassroomNames = async () => {
       try {
@@ -137,7 +154,7 @@ const ClassroomCreation: React.FC = () => {
               </p>
             )}
             <div className="ClassroomCreation__buttonWrapper">
-              <Button type="submit">Create Classroom</Button>
+              <Button variant={classroomExists ? "disabled" : "primary"} type="submit" disabled={classroomExists}>Create Classroom</Button>
               <Button variant="secondary" href="/app/organization/select">
                 Select a different organization
               </Button>