Fix timezone handling in task date analysis

Date comparisons for overdue/due-today detection were using UTC instead
of the user's timezone, causing tasks due today to appear overdue and
tasks due tomorrow to appear as due today for users in non-UTC timezones.

Now fetches user's timezone from RTM settings and converts dates to the
user's local timezone before comparison.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: ljadach

src/rtm_mcp/tools/tasks.py

@@ -76,12 +76,20 @@ async def list_tasks(
         if not include_completed:
             tasks = [t for t in tasks if not t.get("completed")]
 
+        # Get user's timezone for accurate date analysis
+        timezone = None
+        try:
+            settings_result = await client.call("rtm.settings.getList")
+            timezone = settings_result.get("settings", {}).get("timezone")
+        except Exception:
+            pass
+
         return build_response(
             data={
                 "tasks": [format_task(t) for t in tasks],
                 "count": len(tasks),
             },
-            analysis=_analyze_tasks(tasks) if tasks else None,
+            analysis=_analyze_tasks(tasks, timezone=timezone) if tasks else None,
         )
 
     @mcp.tool()
@@ -887,8 +895,14 @@ async def _resolve_task_ids(
     }
 
 
-def _analyze_tasks(tasks: list[dict[str, Any]]) -> dict[str, Any]:
-    """Generate analysis insights for tasks."""
+def _analyze_tasks(tasks: list[dict[str, Any]], timezone: str | None = None) -> dict[str, Any]:
+    """Generate analysis insights for tasks.
+
+    Args:
+        tasks: List of task dictionaries
+        timezone: User's IANA timezone (e.g., 'Europe/Warsaw'). If not provided,
+                  falls back to UTC which may cause incorrect date comparisons.
+    """
     if not tasks:
         return {}
 
@@ -898,8 +912,21 @@ def _analyze_tasks(tasks: list[dict[str, Any]]) -> dict[str, Any]:
     tags_used: set[str] = set()
 
     from datetime import UTC, datetime
-
-    now = datetime.now(UTC)
+    from zoneinfo import ZoneInfo
+
+    # Get current date in user's timezone for accurate comparison
+    # RTM due dates are relative to the user's timezone
+    user_tz = None
+    if timezone:
+        try:
+            user_tz = ZoneInfo(timezone)
+        except Exception:
+            pass
+
+    if user_tz:
+        now = datetime.now(user_tz)
+    else:
+        now = datetime.now(UTC)
     today = now.date()
 
     for task in tasks:
@@ -918,10 +945,18 @@ def _analyze_tasks(tasks: list[dict[str, Any]]) -> dict[str, Any]:
         due = task.get("due")
         if due:
             try:
+                # Parse the due date from RTM
+                # RTM returns dates in UTC with 'Z' suffix
                 due_dt = datetime.fromisoformat(due.replace("Z", "+00:00"))
-                if due_dt.date() < today:
+
+                # Convert to user's timezone for comparison
+                if user_tz:
+                    due_dt = due_dt.astimezone(user_tz)
+
+                due_date = due_dt.date()
+                if due_date < today:
                     overdue_count += 1
-                elif due_dt.date() == today:
+                elif due_date == today:
                     due_today_count += 1
             except ValueError:
                 pass

tests/test_tools/test_tasks.py

@@ -44,3 +44,71 @@ def test_analyze_overdue_tasks(self) -> None:
         result = _analyze_tasks(tasks)
 
         assert result["summary"]["overdue"] == 1
+
+    def test_analyze_tasks_with_timezone(self) -> None:
+        """Test that timezone is properly applied for date comparisons."""
+        from datetime import UTC, datetime, timedelta
+        from zoneinfo import ZoneInfo
+
+        from rtm_mcp.tools.tasks import _analyze_tasks
+
+        # Create a task due "today" in a specific timezone
+        # Use a timezone that's ahead of UTC (e.g., Europe/Warsaw = UTC+1 or UTC+2)
+        test_tz = ZoneInfo("Europe/Warsaw")
+        now_local = datetime.now(test_tz)
+        today_local = now_local.date()
+
+        # Create a due date at midnight local time, converted to UTC
+        due_midnight_local = datetime(
+            today_local.year, today_local.month, today_local.day, 0, 0, 0, tzinfo=test_tz
+        )
+        due_utc = due_midnight_local.astimezone(UTC)
+
+        tasks = [
+            {
+                "priority": "N",
+                "due": due_utc.strftime("%Y-%m-%dT%H:%M:%SZ"),
+                "tags": [],
+            },
+        ]
+
+        # With correct timezone, task should be "due today"
+        result = _analyze_tasks(tasks, timezone="Europe/Warsaw")
+        assert result["summary"]["due_today"] == 1
+        assert result["summary"]["overdue"] == 0
+
+    def test_analyze_tasks_timezone_overdue(self) -> None:
+        """Test that overdue detection works correctly with timezone."""
+        from datetime import datetime, timedelta
+        from zoneinfo import ZoneInfo
+
+        from rtm_mcp.tools.tasks import _analyze_tasks
+
+        # Create a task that was due yesterday in the user's timezone
+        test_tz = ZoneInfo("Europe/Warsaw")
+        now_local = datetime.now(test_tz)
+        yesterday_local = (now_local - timedelta(days=1)).date()
+
+        # Due at noon yesterday local time
+        due_yesterday = datetime(
+            yesterday_local.year,
+            yesterday_local.month,
+            yesterday_local.day,
+            12,
+            0,
+            0,
+            tzinfo=test_tz,
+        )
+        due_utc = due_yesterday.astimezone(ZoneInfo("UTC"))
+
+        tasks = [
+            {
+                "priority": "N",
+                "due": due_utc.strftime("%Y-%m-%dT%H:%M:%SZ"),
+                "tags": [],
+            },
+        ]
+
+        result = _analyze_tasks(tasks, timezone="Europe/Warsaw")
+        assert result["summary"]["overdue"] == 1
+        assert result["summary"]["due_today"] == 0