Billit Invoicing System

Automated invoice generation from Google Calendar work tracking.

How It Works

Uses Peter's brilliant overlay system:

1. Google Calendar work schedule defines normal working days
2. Exception events ("Ziek", "Holiday") mark time off
3. Billable days = Weekdays - Exception days
4. Invoice auto-generated from calendar data

Quick Start

# Generate this month's invoice (dry run)
./create-invoice.sh $(date +%Y-%m) --dry-run

# Create actual invoice  
./create-invoice.sh $(date +%Y-%m)

# Generate last month's invoice
./create-invoice.sh $(date -d "last month" +%Y-%m)

Scripts

• create-invoice.sh - Main script - generates invoice from calendar
• working-days-report-final.sh - Monthly performance analysis
• overlay-tracking-solution.sh - Calendar correlation analysis
• compare-calendar-vs-manual.sh - Compare methods

Workflow

1. Work normally with Google Calendar work schedule
2. Add exception events for time off ("Ziek", "Holiday")
3. End of month: Run ./create-invoice.sh YYYY-MM
4. Review and send invoice in Billit

Legacy Scripts

• add-workday.sh - Manual workday tracking (deprecated)
• create-invoice-manual-backup.sh - Old manual method
• workdays.json - Manual tracking file (no longer needed)

Configuration

Set in .envrc (gitignored):

• BILLIT_API_KEY - Your Billit API key
• BILLIT_CUSTOMER_ID - Default customer (optional)

Benefits

✅ Fully automated - no manual workday entry
✅ Perfect correlation - calendar matches billing
✅ Exception handling - time off automatically subtracted
✅ Elegant system - minimal calendar maintenance
✅ Audit trail - clear workday breakdown in invoices