using System;
using System.Diagnostics;
using System.IO;
using System.Linq;
using System.Security.Cryptography;
using System.Text;
using System.Text.Json;
using System.Text.Json.Serialization;
using System.Threading;
using System.Windows;

namespace AnotherReplayReader.Utils
{
    internal class VerifierPayload
    {
        public string Data { get; }
        public string Signature { get; }
        [JsonIgnore]
        public Lazy<byte[]> ByteData { get; }
        [JsonIgnore]
        public Lazy<byte[]> ByteSignature { get; }

        public VerifierPayload(string data, string signature)
        {
            Data = data;
            Signature = signature;
            ByteData = new(() => Convert.FromBase64String(Data),
                           LazyThreadSafetyMode.PublicationOnly);
            ByteSignature = new(() => Convert.FromBase64String(Signature),
                                LazyThreadSafetyMode.PublicationOnly);
        }

        public static VerifierPayload FromBytes(byte[] data, byte[] signature)
        {
            return new(Convert.ToBase64String(data), Convert.ToBase64String(signature));
        }
    }

    internal class Verifier
    {
        private const string _publicKey = @"<RSAKeyValue><Modulus>3vw5CoFRDFt2ri4jLDTu75cw1U/tCRjya7q8X/IdULaOJOYG8C+uqrF2Atb4ou+4SrmF+bvJM9cFsf3yO7XpeIDpkxD3KGbIEw+0JixTIIm+y5xlLKDDwbZHnYjJOBTt6JBn0yqwx7vY2UEZIcRU6wlOmUapnkpiaC2anNhSPqk=</Modulus><Exponent>AQAB</Exponent></RSAKeyValue>";

        public static bool Verify(VerifierPayload payload)
        {
            using var rsa = new RSACng();
            rsa.FromXmlString(_publicKey);
            return rsa.VerifyData(payload.ByteData.Value, payload.ByteSignature.Value, HashAlgorithmName.SHA256, RSASignaturePadding.Pss);
        }

        public static void Sign(object sample)
        {
            var fileName = Path.GetTempFileName();
            try
            {
                var ea = Enumerable.Repeat<byte>(0xEA, 1024).ToArray();
                const string splitter = "|DuplexBarrier|";
                var isByteArray = false;
                if (sample is string sampleText)
                {
                    File.WriteAllText(fileName, $"输入私钥信息以及需要签名的数据，用 `{splitter}` 分开\r\n\r\n{sampleText}");
                }
                else if (sample is byte[] readyArray)
                {
                    isByteArray = true;
                    File.WriteAllText(fileName, $"输入私钥信息以及需要签名的数据{splitter}{Convert.ToBase64String(readyArray)}{splitter}");
                }
                using (var process = Process.Start("notepad.exe", fileName))
                {
                    process.WaitForExit();
                }
                var splitted = File.ReadAllText(fileName).Split(new[] { splitter }, StringSplitOptions.RemoveEmptyEntries);
                File.WriteAllBytes(fileName, ea);
                byte[] bytes;
                byte[] signature;

                using (var rsa = new RSACng())
                {
                    rsa.FromXmlString(splitted[0]);
                    var text = splitted[1];
                    splitted = null;
                    GC.Collect();
                    MessageBox.Show(text, $"快来确认一下~");
                    bytes = isByteArray
                        ? Convert.FromBase64String(text)
                        : Encoding.UTF8.GetBytes(text);
                    signature = rsa.SignData(bytes, HashAlgorithmName.SHA256, RSASignaturePadding.Pss);
                }
                GC.Collect();
                var payload = VerifierPayload.FromBytes(bytes, signature);
                var serialized = JsonSerializer.Serialize(payload, Network.CommonJsonOptions);
                var choice = MessageBox.Show(serialized, "嗯哼", MessageBoxButton.YesNo);
                while (choice == MessageBoxResult.Yes)
                {
                    File.WriteAllText(fileName, serialized);
                    using (var process = Process.Start("notepad.exe", fileName))
                    {
                        process.WaitForExit();
                    }
                    using var rsa = new RSACng();
                    rsa.FromXmlString(_publicKey);
                    var checkContent = File.ReadAllText(fileName);
                    var check = JsonSerializer.Deserialize<VerifierPayload>(checkContent, Network.CommonJsonOptions) ?? new("", "");
                    var checkData = Convert.FromBase64String(check.Data);
                    var checkSignature = Convert.FromBase64String(check.Signature);
                    var verified = rsa.VerifyData(checkData, checkSignature, HashAlgorithmName.SHA256, RSASignaturePadding.Pss);
                    choice = MessageBox.Show($"结果：{verified}", "嗯哼", MessageBoxButton.YesNo);
                }
            }
            finally
            {
                File.Delete(fileName);
            }
        }
    }
}