package util

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

const (
	SECRET_KEY = ")VQbB(vpy=U(wcp)"
)

// 加密字符串
func Encrypt(plainText, key string) (string, error) {
	block, err := aes.NewCipher([]byte(key))
	if err != nil {
		return "", err
	}

	cipherText := make([]byte, aes.BlockSize+len(plainText))
	iv := cipherText[:aes.BlockSize]
	if _, err := io.ReadFull(rand.Reader, iv); err != nil {
		return "", err
	}

	stream := cipher.NewCFBEncrypter(block, iv)
	stream.XORKeyStream(cipherText[aes.BlockSize:], []byte(plainText))

	return base64.URLEncoding.EncodeToString(cipherText), nil
}

// 解密字符串
func Decrypt(cipherText, key string) (string, error) {
	cipherTextBytes, err := base64.URLEncoding.DecodeString(cipherText)
	if err != nil {
		return "", err
	}

	block, err := aes.NewCipher([]byte(key))
	if err != nil {
		return "", err
	}

	if len(cipherTextBytes) < aes.BlockSize {
		return "", fmt.Errorf("cipherText too short")
	}

	iv := cipherTextBytes[:aes.BlockSize]
	cipherTextBytes = cipherTextBytes[aes.BlockSize:]

	stream := cipher.NewCFBDecrypter(block, iv)
	stream.XORKeyStream(cipherTextBytes, cipherTextBytes)

	return string(cipherTextBytes), nil
}

func GetNowTime() int64 {
	T := time.Now()
	return T.Unix()
}

func Int(a interface{}) int {
	if a == nil {
		return 0
	}
	switch v := a.(type) {
	case int:
		return v
	case int32:
		return int(v)
	case int64:
		return int(v)
	case float64:
		return int(v)
	case string:
		r, err := strconv.Atoi(v)
		if err != nil {
			return 0
		}
		return r
	}
	return 0
}