// Code extracted from vendor/github.com/ethereum/go-ethereum/common/types.go

package statusproto

import (
	"encoding/hex"
)

const (
	// HashLength is the expected length of the hash
	HashLength = 32
)

// Hash represents the 32 byte Keccak256 hash of arbitrary data.
type Hash [HashLength]byte

// Encode encodes b as a hex string with 0x prefix.
func encode(b []byte) string {
	enc := make([]byte, len(b)*2+2)
	copy(enc, "0x")
	hex.Encode(enc[2:], b)
	return string(enc)
}

// has0xPrefix validates str begins with '0x' or '0X'.
func has0xPrefix(str string) bool {
	return len(str) >= 2 && str[0] == '0' && (str[1] == 'x' || str[1] == 'X')
}

// Hex2Bytes returns the bytes represented by the hexadecimal string str.
func Hex2Bytes(str string) []byte {
	h, _ := hex.DecodeString(str)
	return h
}

// FromHex returns the bytes represented by the hexadecimal string s.
// s may be prefixed with "0x".
func FromHex(s string) []byte {
	if has0xPrefix(s) {
		s = s[2:]
	}
	if len(s)%2 == 1 {
		s = "0" + s
	}
	return Hex2Bytes(s)
}

// HexToHash sets byte representation of s to hash.
// If b is larger than len(h), b will be cropped from the left.
func HexToHash(s string) Hash { return BytesToHash(FromHex(s)) }

// Hex converts a hash to a hex string.
func (h *Hash) Hex() string { return encode(h[:]) }

// Bytes gets the byte representation of the underlying hash.
func (h Hash) Bytes() []byte { return h[:] }

// String implements the stringer interface and is used also by the logger when
// doing full logging into a file.
func (h *Hash) String() string {
	return h.Hex()
}

// SetBytes sets the hash to the value of b.
// If b is larger than len(h), b will be cropped from the left.
func (h *Hash) SetBytes(b []byte) {
	if len(b) > len(h) {
		b = b[len(b)-HashLength:]
	}

	copy(h[HashLength-len(b):], b)
}

// BytesToHash sets b to hash.
// If b is larger than len(h), b will be cropped from the left.
func BytesToHash(b []byte) Hash {
	var h Hash
	h.SetBytes(b)
	return h
}