feat: US-001 - Backend: DELETE endpoint for uncheck (toggle support)

dashboard/api.py

@@ -80,7 +80,9 @@ class TaskBoardHandler(SimpleHTTPRequestHandler):
             self.send_error(404)
     
     def do_DELETE(self):
-        if self.path.startswith('/api/habits/'):
+        if self.path.startswith('/api/habits/') and '/check' in self.path:
+            self.handle_habits_uncheck()
+        elif self.path.startswith('/api/habits/'):
             self.handle_habits_delete()
         else:
             self.send_error(404)
@@ -1771,6 +1773,88 @@ class TaskBoardHandler(SimpleHTTPRequestHandler):
         except Exception as e:
             self.send_json({'error': str(e)}, 500)
     
+    def handle_habits_uncheck(self):
+        """Uncheck a habit (remove completion for a specific date)."""
+        try:
+            # Extract habit ID from path (/api/habits/{id}/check)
+            path_parts = self.path.split('?')[0].split('/')
+            if len(path_parts) < 5:
+                self.send_json({'error': 'Invalid path'}, 400)
+                return
+            
+            habit_id = path_parts[3]
+            
+            # Parse query string for date parameter
+            parsed = urlparse(self.path)
+            query_params = parse_qs(parsed.query)
+            
+            # Get date from query string (required)
+            if 'date' not in query_params:
+                self.send_json({'error': 'date parameter is required (format: YYYY-MM-DD)'}, 400)
+                return
+            
+            target_date = query_params['date'][0]
+            
+            # Validate date format
+            try:
+                datetime.fromisoformat(target_date)
+            except ValueError:
+                self.send_json({'error': 'Invalid date format. Use YYYY-MM-DD'}, 400)
+                return
+            
+            # Read existing habits
+            if not HABITS_FILE.exists():
+                self.send_json({'error': 'Habit not found'}, 404)
+                return
+            
+            with open(HABITS_FILE, 'r', encoding='utf-8') as f:
+                habits_data = json.load(f)
+            
+            # Find habit
+            habit = None
+            for h in habits_data.get('habits', []):
+                if h['id'] == habit_id:
+                    habit = h
+                    break
+            
+            if not habit:
+                self.send_json({'error': 'Habit not found'}, 404)
+                return
+            
+            # Find and remove the completion for the specified date
+            completions = habit.get('completions', [])
+            completion_found = False
+            for i, completion in enumerate(completions):
+                if completion.get('date') == target_date:
+                    completions.pop(i)
+                    completion_found = True
+                    break
+            
+            if not completion_found:
+                self.send_json({'error': 'No completion found for the specified date'}, 404)
+                return
+            
+            # Recalculate streak after removing completion
+            current_streak = habits_helpers.calculate_streak(habit)
+            habit['streak']['current'] = current_streak
+            
+            # Update best streak if needed (best never decreases, but we keep it for consistency)
+            if current_streak > habit['streak']['best']:
+                habit['streak']['best'] = current_streak
+            
+            # Update timestamp
+            habit['updatedAt'] = datetime.now().isoformat()
+            habits_data['lastUpdated'] = habit['updatedAt']
+            
+            # Save to file
+            with open(HABITS_FILE, 'w', encoding='utf-8') as f:
+                json.dump(habits_data, f, indent=2)
+            
+            # Return updated habit
+            self.send_json(habit, 200)
+        except Exception as e:
+            self.send_json({'error': str(e)}, 500)
+    
     def handle_habits_skip(self):
         """Skip a day using a life to preserve streak."""
         try: