package storage

import (
	"context"
	"log/slog"
	"time"
)

// RunRetention periodically deletes records older than retentionDays.
// It runs one prune immediately on startup, then on the given interval.
// It returns when ctx is cancelled.
func RunRetention(ctx context.Context, store Store, retentionDays int, interval time.Duration, logger *slog.Logger) {
	prune := func() {
		cutoff := time.Now().UTC().AddDate(0, 0, -retentionDays)
		n, err := store.DeleteRecordsBefore(ctx, cutoff)
		if err != nil {
			logger.Error("retention prune failed", "err", err)
			return
		}
		if n > 0 {
			logger.Info("retention prune completed", "deleted_rows", n)
		}
	}

	prune()

	ticker := time.NewTicker(interval)
	defer ticker.Stop()

	for {
		select {
		case <-ctx.Done():
			return
		case <-ticker.C:
			prune()
		}
	}
}