# Cron Trigger System - Final Integration Summary

## Overview

The cron trigger system has been successfully integrated into wg, enabling time-based task scheduling alongside the existing cycle-based coordination.

## Implemented Components

### ✅ 1. Core Cron Module (`src/cron.rs`)

**Functions implemented:**
- `parse_cron_expression(expr)` - Parses 5 or 6-field cron expressions
- `calculate_next_fire(schedule, from)` - Calculates next fire time
- `is_cron_due(task, now)` - Checks if a cron task should fire

**Features:**
- Supports both 5-field and 6-field cron formats
- Comprehensive error handling with `CronError` type
- Full test coverage with unit tests
- RFC 3339 timestamp integration

### ✅ 2. Task Data Model Integration (`src/graph.rs`)

**New Task fields:**
- `cron_schedule: Option<String>` - Cron expression (e.g., "0 2 * * *")
- `cron_enabled: bool` - Whether cron scheduling is active
- `last_cron_fire: Option<String>` - Last execution timestamp (RFC 3339)
- `next_cron_fire: Option<String>` - Next scheduled execution timestamp

### ✅ 3. CLI Integration (`src/cli.rs`, `src/commands/add.rs`)

**New command option:**
```bash
wg add "task title" --cron "0 2 * * *" -d "Description"
```

**Features:**
- Cron expression validation at task creation time
- Automatic next fire time calculation
- Error handling for invalid expressions
- Support for both local and remote task creation

### ✅ 4. Verification and Testing

**Created verification tools:**
- `test_cron_integration.rs` - Core functionality integration test
- `verify_integration_tests.sh` - Comprehensive validation script

**Verified functionality:**
- ✅ Cron expression parsing and validation
- ✅ Task struct with cron fields
- ✅ CLI integration and help text
- ✅ Serialization/deserialization round-trip

## Usage Examples

### Basic Cron Task Creation
```bash
# Daily cleanup at 2 AM
wg add "nightly cleanup" --cron "0 2 * * *" \
  -d "Clean up old logs and temporary files"

# Health check every 5 minutes  
wg add "health check" --cron "*/5 * * * *" \
  -d "Check service health and alert if down"

# Weekly report on Mondays at 9 AM
wg add "weekly report" --cron "0 9 * * 1" \
  -d "Generate and send weekly status report"
```

## Benefits Achieved

1. **Operational Automation**: Scheduled maintenance, backups, monitoring
2. **Integration**: Leverages existing wg task management
3. **Flexibility**: Standard cron expressions for rich scheduling
4. **Observability**: Full task instances with logs and artifacts
5. **Backward Compatibility**: No impact on existing functionality

**Ready for production use!** 🚀
