using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Security.Cryptography;
using System.Text;
using System.Threading.Tasks;

namespace Module.Socket.Tool
{
    /// <summary>
    /// AES加密
    /// </summary>
    public class AesEncryption
    {
        private static readonly byte[] Key = Encoding.UTF8.GetBytes("YourSecretKeyHere12345678"); // 必须是32字节（256位）  
        private static readonly byte[] Iv = Encoding.UTF8.GetBytes("YourInitializationVectorHere"); // 必须是16字节（128位）  

        public static byte[] EncryptStringToBytes(string plainText)
        {
            if (plainText == null || plainText.Length <= 0)
                throw new ArgumentNullException(nameof(plainText));
            if (Key == null || Key.Length != 32)
                throw new ArgumentNullException(nameof(Key));
            if (Iv == null || Iv.Length != 16)
                throw new ArgumentNullException(nameof(Iv));

            byte[] encrypted;

            using (Aes aesAlg = Aes.Create())
            {
                aesAlg.Key = Key;
                aesAlg.IV = Iv;

                ICryptoTransform encryptor = aesAlg.CreateEncryptor(aesAlg.Key, aesAlg.IV);

                using (MemoryStream msEncrypt = new MemoryStream())
                {
                    using (CryptoStream csEncrypt = new CryptoStream(msEncrypt, encryptor, CryptoStreamMode.Write))
                    using (StreamWriter swEncrypt = new StreamWriter(csEncrypt))
                    {
                        swEncrypt.Write(plainText);
                    }
                    encrypted = msEncrypt.ToArray();
                }
            }

            return encrypted;
        }

        public static string DecryptBytesToString(byte[] cipherText)
        {
            if (cipherText == null || cipherText.Length <= 0)
                throw new ArgumentNullException(nameof(cipherText));
            if (Key == null || Key.Length != 32)
                throw new ArgumentNullException(nameof(Key));
            if (Iv == null || Iv.Length != 16)
                throw new ArgumentNullException(nameof(Iv));

            string plaintext = null;

            using (Aes aesAlg = Aes.Create())
            {
                aesAlg.Key = Key;
                aesAlg.IV = Iv;

                ICryptoTransform decryptor = aesAlg.CreateDecryptor(aesAlg.Key, aesAlg.IV);

                using (MemoryStream msDecrypt = new MemoryStream(cipherText))
                using (CryptoStream csDecrypt = new CryptoStream(msDecrypt, decryptor, CryptoStreamMode.Read))
                using (StreamReader srDecrypt = new StreamReader(csDecrypt))
                {
                    plaintext = srDecrypt.ReadToEnd();
                }
            }

            return plaintext;
        }
    }
}