package main

import (
	"bytes"
	"crypto/aes"
	stdcipher "crypto/cipher"
	"encoding/base64"
	"fmt"
	"strings"

	"github.com/dromara/dongle"
	"github.com/dromara/dongle/crypto/cipher"
)

func main() {
	key := []byte("dongle1234567890")
	iv := []byte("1234567890123456")
	c := cipher.NewAesCipher(cipher.CFB)
	c.SetKey(key)
	c.SetIV(iv)
	c.SetPadding(cipher.PKCS7)

	text := strings.Repeat("1", 48)
	ciphertext := dongle.Encrypt.FromString(text).ByAes(c).ToBase64String()
	plaintext := dongle.Decrypt.FromBase64String(ciphertext).ByAes(c).ToString()
	fmt.Println(plaintext == text)

	text = strings.Repeat("1", 49)
	ciphertext = dongle.Encrypt.FromString(text).ByAes(c).ToBase64String()
	plaintext = dongle.Decrypt.FromBase64String(ciphertext).ByAes(c).ToString()
	fmt.Println(plaintext == text)

	fmt.Println("---")

	text = strings.Repeat("1", 48)
	ciphertext = stdEncrypt(key, iv, text)
	plaintext = stdDecrypt(key, iv, ciphertext)
	fmt.Println(plaintext == text)

	text = strings.Repeat("1", 49)
	ciphertext = stdEncrypt(key, iv, text)
	plaintext = stdDecrypt(key, iv, ciphertext)
	fmt.Println(plaintext == text)
}

func pkcs7Padding(src []byte, blockSize int) []byte {
	paddingSize := blockSize - len(src)%blockSize
	paddingText := bytes.Repeat([]byte{byte(paddingSize)}, paddingSize)
	return append(src, paddingText...)
}

func pkcs7UnPadding(src []byte) []byte {
	if len(src) == 0 {
		return []byte("")
	}
	n := len(src) - int(src[len(src)-1])
	return src[0:n]
}

func stdEncrypt(key []byte, iv []byte, text string) string {
	block, err := aes.NewCipher(key)
	if err != nil {
		panic(err)
	}

	plaintext := pkcs7Padding([]byte(text), block.BlockSize())

	ciphertext := make([]byte, len(plaintext))

	stream := stdcipher.NewCFBEncrypter(block, iv[:])
	stream.XORKeyStream(ciphertext, plaintext)

	return base64.RawURLEncoding.EncodeToString(ciphertext)
}

func stdDecrypt(key []byte, iv []byte, text string) string {
	block, err := aes.NewCipher(key)
	if err != nil {
		panic(err)
	}

	ciphertext, err := base64.RawURLEncoding.DecodeString(text)
	if err != nil {
		panic(err)
	}

	plaintext := make([]byte, len(ciphertext))

	stream := stdcipher.NewCFBDecrypter(block, iv[:])
	stream.XORKeyStream(plaintext, ciphertext)

	return string(pkcs7UnPadding(plaintext))
}