bsdaily/cmd/bsdaily/main.go

package main

import (
	"fmt"
	"log/slog"
	"os"
	"time"

	"git.eeqj.de/sneak/bsdaily/internal/bsdaily"
	"github.com/spf13/cobra"
)

func main() {
	logger := slog.New(slog.NewTextHandler(os.Stderr, &slog.HandlerOptions{
		Level: slog.LevelInfo,
	}))
	slog.SetDefault(logger)

	var dateFlag string
	var fromFlag string
	var toFlag string

	rootCmd := &cobra.Command{
		Use:          "bsdaily",
		Short:        "Extract a single day's data from the latest daily snapshot",
		SilenceUsage: true,
		RunE: func(cmd *cobra.Command, args []string) error {
			hasDate := dateFlag != ""
			hasFrom := fromFlag != ""
			hasTo := toFlag != ""

			// Validate mutual exclusivity
			if hasDate && (hasFrom || hasTo) {
				return fmt.Errorf("--date and --from/--to are mutually exclusive")
			}
			if hasFrom != hasTo {
				if hasFrom {
					return fmt.Errorf("--from requires --to")
				}
				return fmt.Errorf("--to requires --from")
			}

			var targetDates []time.Time

			if hasDate {
				t, err := time.Parse("2006-01-02", dateFlag)
				if err != nil {
					return fmt.Errorf("invalid --date %q (expected YYYY-MM-DD): %w", dateFlag, err)
				}
				targetDates = []time.Time{t}
			} else if hasFrom {
				from, err := time.Parse("2006-01-02", fromFlag)
				if err != nil {
					return fmt.Errorf("invalid --from %q (expected YYYY-MM-DD): %w", fromFlag, err)
				}
				to, err := time.Parse("2006-01-02", toFlag)
				if err != nil {
					return fmt.Errorf("invalid --to %q (expected YYYY-MM-DD): %w", toFlag, err)
				}
				if from.After(to) {
					return fmt.Errorf("--from %s is after --to %s", fromFlag, toFlag)
				}
				for d := from; !d.After(to); d = d.AddDate(0, 0, 1) {
					targetDates = append(targetDates, d)
				}
			}
			// else: targetDates remains nil → Run() defaults to snapshot date minus one

			if err := bsdaily.Run(targetDates); err != nil {
				return err
			}
			slog.Info("completed successfully")
			return nil
		},
	}

	rootCmd.Flags().StringVarP(&dateFlag, "date", "d", "", "target date to extract (YYYY-MM-DD); defaults to snapshot date minus one day")
	rootCmd.Flags().StringVar(&fromFlag, "from", "", "start of date range to extract (YYYY-MM-DD, inclusive); use with --to")
	rootCmd.Flags().StringVar(&toFlag, "to", "", "end of date range to extract (YYYY-MM-DD, inclusive); use with --from")

	if err := rootCmd.Execute(); err != nil {
		os.Exit(1)
	}
}