order-bak/docs/superpowers/specs/2026-04-21-backup-days-param-design.md

Backup Days Parameter Design

Summary

Replace the --start / --end date range parameters on the backup command with a single --days N parameter that backs up all orders older than N days. The minimum value is 1 (today's data is never backed up).

Current Behavior

order-bak backup --start 2025-01-01 --end 2025-02-01

Backs up orders where start <= OrderTime < end and state == 1.

New Behavior

order-bak backup --days 7

Backs up all orders where OrderTime < cutoff and state == 1, where cutoff = today_utc - timedelta(days=N).

Example: --days 7 on April 21 → cutoff is April 14 00:00 UTC → backs up all orders with OrderTime before April 14.

Changes

cli.py

• Remove --start and --end options
• Add --days option: required, int, must be >= 1
• Compute cutoff = datetime.now(timezone.utc).replace(hour=0, minute=0, second=0, microsecond=0) - timedelta(days=days)
• Pass cutoff to backup_orders()

backup.py

• Change signature from backup_orders(scan_path, backup_dir, start, end) to backup_orders(scan_path, backup_dir, cutoff)
• Replace filter if order_time < start or order_time >= end with if order_time >= cutoff

test_backup.py

• Update all existing tests to pass cutoff instead of start/end
• Add edge cases: cutoff exactly at midnight, N=1 (only today excluded)

Unchanged

• scan command, delete command, config, csv_utils
• State filtering (state == 1), OrderTime null check
• Output format (per-date CSV files in backups/)