// Copyright © 2022 Weald Technology Trading.
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package validatorcredentialsget

import (
	"context"
	"encoding/hex"
	"fmt"
	"strings"

	ethutil "github.com/wealdtech/go-eth2-util"
)

func (c *command) output(_ context.Context) (string, error) {
	if c.quiet {
		return "", nil
	}

	builder := strings.Builder{}

	switch c.validatorInfo.Validator.WithdrawalCredentials[0] {
	case 0:
		builder.WriteString("BLS credentials: ")
		builder.WriteString(fmt.Sprintf("%#x", c.validatorInfo.Validator.WithdrawalCredentials))
	case 1:
		builder.WriteString("Ethereum execution address: ")
		builder.WriteString(addressBytesToEIP55(c.validatorInfo.Validator.WithdrawalCredentials[12:]))
		if c.verbose {
			builder.WriteString("\n")
			builder.WriteString("Withdrawal credentials: ")
			builder.WriteString(fmt.Sprintf("%#x", c.validatorInfo.Validator.WithdrawalCredentials))
		}
	}

	return builder.String(), nil
}

// addressBytesToEIP55 converts a byte array in to an EIP-55 string format.
func addressBytesToEIP55(address []byte) string {
	bytes := []byte(hex.EncodeToString(address))
	hash := ethutil.Keccak256(bytes)
	for i := 0; i < len(bytes); i++ {
		hashByte := hash[i/2]
		if i%2 == 0 {
			hashByte >>= 4
		} else {
			hashByte &= 0xf
		}
		if bytes[i] > '9' && hashByte > 7 {
			bytes[i] -= 32
		}
	}

	return fmt.Sprintf("0x%s", string(bytes))
}