package sign

import (
	"fmt"

	"git.sigsum.org/sigsum-go/pkg/hex"
	"git.sigsum.org/sigsum-go/pkg/types"
	"git.sigsum.org/sigsum-tools-go/internal/util"
)

func Main(_ []string, optPriv string, optShardHint uint64) error {
	data, err := util.BytesFromStdin()
	if err != nil {
		return fmt.Errorf("sign: %v", err)
	}
	priv, err := util.SignerFromHex(optPriv)
	if err != nil {
		return fmt.Errorf("sign: %v", err)
	}
	preimage := types.HashFn(data)
	stm := types.Statement{
		ShardHint: optShardHint,
		Checksum:  *types.HashFn(preimage[:]),
	}
	sig, err := stm.Sign(priv)
	if err != nil {
		fmt.Errorf("sign: %v", err)
	}

	fmt.Printf("%s\n", hex.Serialize(sig[:]))
	return nil
}