Add weekly progress and validation

app/Models/Category.php

@@ -1,4 +1,4 @@
-<?php
+<?php
 
 class Category
 {
@@ -8,4 +8,12 @@ class Category
             ->query('SELECT id, name, color FROM categories ORDER BY name')
             ->fetchAll();
     }
+
+    public static function exists(int $id): bool
+    {
+        $statement = Database::connection()->prepare('SELECT id FROM categories WHERE id = :id LIMIT 1');
+        $statement->execute(['id' => $id]);
+
+        return (bool) $statement->fetch();
+    }
 }

app/Models/Habit.php

@@ -1,4 +1,4 @@
-<?php
+<?php
 
 class Habit
 {
@@ -19,7 +19,11 @@ class Habit
         }
 
         $sql = 'SELECT h.*, c.name AS category_name, c.color AS category_color,
-                    CASE WHEN hl.id IS NULL THEN 0 ELSE 1 END AS done_today
+                    CASE WHEN hl.id IS NULL THEN 0 ELSE 1 END AS done_today,
+                    (SELECT COUNT(*)
+                     FROM habit_logs hwl
+                     WHERE hwl.habit_id = h.id
+                     AND YEARWEEK(hwl.completed_on, 1) = YEARWEEK(CURRENT_DATE, 1)) AS completed_this_week
                 FROM habits h
                 LEFT JOIN categories c ON c.id = h.category_id
                 LEFT JOIN habit_logs hl