# Tasks: add-schedule-triggers

## Phase 1: Backend - Cron Support

- [x] 1.1 Add croniter dependency to requirements.txt
- [x] 1.2 Create TriggerSchedulerService (`backend/app/services/trigger_scheduler.py`)
- [x] 1.3 Implement cron expression validation in trigger creation
- [x] 1.4 Implement `evaluate_schedule_triggers()` method

## Phase 2: Backend - Scheduler Integration

- [x] 2.1 Add scheduled job to evaluate schedule triggers (every minute)
- [x] 2.2 Implement deadline reminder logic (check tasks N days before due)
- [x] 2.3 Update trigger logs for schedule trigger executions

## Phase 3: Backend - Testing

- [x] 3.1 Unit tests for cron expression parsing
- [x] 3.2 Unit tests for deadline reminder logic
- [x] 3.3 Integration tests for schedule trigger execution

## Validation Criteria

- [x] Cron expressions are validated on trigger creation
- [x] Schedule triggers execute at specified times
- [x] Deadline reminders sent N days before task due date