Add configuration rules, refactor settings management, and enhance import functionality

- Introduced a new configuration file `.cursorrules` to define coding standards, error handling, testing requirements, and project-specific guidelines.
- Refactored `config.py` to implement a `Settings` dataclass for better management of environment variables, improving testability and maintainability.
- Updated the import duty schedule handler to utilize session management with `session_scope`, ensuring proper database session handling.
- Enhanced the import service to streamline the duty schedule import process, improving code organization and readability.
- Added new service layer functions to encapsulate business logic related to group duty pinning and duty schedule imports.
- Updated README documentation to reflect the new configuration structure and improved import functionality.

services/import_service.py

@@ -0,0 +1,70 @@
+"""Import duty schedule: delete range, insert duties/unavailable/vacation. Accepts session."""
+
+from datetime import date, timedelta
+
+from sqlalchemy.orm import Session
+
+from db.repository import (
+    get_or_create_user_by_full_name,
+    delete_duties_in_range,
+    insert_duty,
+)
+from importers.duty_schedule import DutyScheduleResult
+from utils.dates import day_start_iso, day_end_iso, duty_to_iso
+
+
+def _consecutive_date_ranges(dates: list[date]) -> list[tuple[date, date]]:
+    """Sort dates and merge consecutive ones into (first, last) ranges. Empty list -> []."""
+    if not dates:
+        return []
+    sorted_dates = sorted(set(dates))
+    ranges: list[tuple[date, date]] = []
+    start_d = end_d = sorted_dates[0]
+    for d in sorted_dates[1:]:
+        if (d - end_d).days == 1:
+            end_d = d
+        else:
+            ranges.append((start_d, end_d))
+            start_d = end_d = d
+    ranges.append((start_d, end_d))
+    return ranges
+
+
+def run_import(
+    session: Session,
+    result: DutyScheduleResult,
+    hour_utc: int,
+    minute_utc: int,
+) -> tuple[int, int, int, int]:
+    """Run import: delete range per user, insert duty/unavailable/vacation. Returns (num_users, num_duty, num_unavailable, num_vacation)."""
+    from_date_str = result.start_date.isoformat()
+    to_date_str = result.end_date.isoformat()
+    num_duty = num_unavailable = num_vacation = 0
+    for entry in result.entries:
+        user = get_or_create_user_by_full_name(session, entry.full_name)
+        delete_duties_in_range(session, user.id, from_date_str, to_date_str)
+        for d in entry.duty_dates:
+            start_at = duty_to_iso(d, hour_utc, minute_utc)
+            d_next = d + timedelta(days=1)
+            end_at = duty_to_iso(d_next, hour_utc, minute_utc)
+            insert_duty(session, user.id, start_at, end_at, event_type="duty")
+            num_duty += 1
+        for d in entry.unavailable_dates:
+            insert_duty(
+                session,
+                user.id,
+                day_start_iso(d),
+                day_end_iso(d),
+                event_type="unavailable",
+            )
+            num_unavailable += 1
+        for start_d, end_d in _consecutive_date_ranges(entry.vacation_dates):
+            insert_duty(
+                session,
+                user.id,
+                day_start_iso(start_d),
+                day_end_iso(end_d),
+                event_type="vacation",
+            )
+            num_vacation += 1
+    return (len(result.entries), num_duty, num_unavailable, num_vacation)