package shadow

import (
	"bytes"
	"crypto/md5"
	"io"
	"math/rand"
)

type RandReader struct {
	io.Reader
}

func (r RandReader) Read(p []byte) (n int, err error) {
	buf := make([]byte, 32)
	randBytes := md5.Sum(RandomByte(16))
	copy(buf[0:], randBytes[:])

	preHashData := bytes.NewBuffer(randBytes[:])
	sum := md5.Sum([]byte(HandshakePassword))
	preHashData.Write(sum[:])
	hash := md5.Sum(preHashData.Bytes())
	copy(buf[16:], hash[:])
	copy(p, buf)
	return 32, nil
}

func RandomByte(size int) []byte {
	buf := make([]byte, size)
	for i := 0; i < size; i++ {
		buf[i] = byte(rand.Intn(255))
	}
	return buf
}

func VerifyKey(p []byte, key string) bool {
	if len(p) != 32 {
		return false
	}
	buf := make([]byte, 16)
	copy(buf, p[0:16])
	buffer := bytes.NewBuffer(buf)
	sum := md5.Sum([]byte(key))
	buffer.Write(sum[:])

	hash := md5.Sum(buffer.Bytes())

	return bytes.Equal(hash[:], p[16:])
}