Added authentication functionality and simple role based model

add_subtask.php

@@ -1,18 +1,32 @@
 <?php
 require 'db.php';
+require 'auth.php';
+
+header('Content-Type: application/json');
+require_login();
+
+$user_id = current_user_id();
 
 $data = json_decode(file_get_contents('php://input'), true);
 $name = trim($data['name'] ?? '');
 $task_id = intval($data['task_id'] ?? 0);
 
 if ($name === '' || $task_id <= 0) {
-	http_response_code(400);
-	echo json_encode(['error' => 'Invalid input']);
-	exit;
+    http_response_code(400);
+    echo json_encode(['success' => false, 'error' => 'Invalid input']);
+    exit;
 }
 
-$stmt = $pdo->prepare("INSERT INTO subtasks (task_id, name) VALUES (?, ?)");
-$stmt->execute([$task_id, $name]);
+// Ensure task belongs to this user
+$stmt = $pdo->prepare("SELECT id FROM tasks WHERE id = ? AND user_id = ? LIMIT 1");
+$stmt->execute([$task_id, $user_id]);
+if (!$stmt->fetchColumn()) {
+    http_response_code(403);
+    echo json_encode(['success' => false, 'error' => 'Forbidden']);
+    exit;
+}
+
+$stmt = $pdo->prepare("INSERT INTO subtasks (user_id, task_id, name) VALUES (?, ?, ?)");
+$stmt->execute([$user_id, $task_id, $name]);
 
 echo json_encode(['success' => true, 'id' => $pdo->lastInsertId()]);
-?>