package tool

import (
	"crypto/aes"
	"crypto/cipher"
	"crypto/rand"
	"encoding/base64"
	"fmt"
	"io"
	"unicode"
)

func Encrypt(key []byte, text string) string {

	plaintext := []byte(text)

	block, err := aes.NewCipher(key)
	if err != nil {
		panic(err)
	}

	ciphertext := make([]byte, aes.BlockSize+len(plaintext))
	iv := ciphertext[:aes.BlockSize]
	if _, err := io.ReadFull(rand.Reader, iv); err != nil {
		panic(err)
	}

	stream := cipher.NewCFBEncrypter(block, iv)
	stream.XORKeyStream(ciphertext[aes.BlockSize:], plaintext)

	return base64.URLEncoding.EncodeToString(ciphertext)
}

func Decrypt(key []byte, cryptoText string) string {
	ciphertext, _ := base64.URLEncoding.DecodeString(cryptoText)

	block, err := aes.NewCipher(key)
	if err != nil {
		panic(err)
	}

	if len(ciphertext) < aes.BlockSize {
		panic("ciphertext too short")
	}
	iv := ciphertext[:aes.BlockSize]
	ciphertext = ciphertext[aes.BlockSize:]

	stream := cipher.NewCFBDecrypter(block, iv)

	stream.XORKeyStream(ciphertext, ciphertext)

	return fmt.Sprintf("%s", ciphertext)
}

func IsPasswordValid(s string) bool {
	var (
		hasMinLen  = false
		hasUpper   = false
		hasLower   = false
		hasNumber  = false
		hasSpecial = false
	)
	if len(s) >= 7 {
		hasMinLen = true
	}
	for _, char := range s {
		switch {
		case unicode.IsUpper(char):
			hasUpper = true
		case unicode.IsLower(char):
			hasLower = true
		case unicode.IsNumber(char):
			hasNumber = true
		case unicode.IsPunct(char) || unicode.IsSymbol(char):
			hasSpecial = true
		}
	}
	return hasMinLen && hasUpper && hasLower && hasNumber && hasSpecial
}