using Microsoft.IdentityModel.Tokens;
using Ryujinx.Common.Logging;
using Ryujinx.HLE.HOS.Kernel.Threading;
using Ryujinx.HLE.HOS.Services.Account.Acc.AsyncContext;
using System;
using System.IdentityModel.Tokens.Jwt;
using System.Security.Cryptography;
using System.Text;
using System.Threading;
using System.Threading.Tasks;

namespace Ryujinx.HLE.HOS.Services.Account.Acc.AccountService
{
    class ManagerServer
    {
        // TODO: Determine where and how NetworkServiceAccountId is set.
        private const long NetworkServiceAccountId = 0xcafe;

        private UserId _userId;

        public ManagerServer(UserId userId)
        {
            _userId = userId;
        }

        private static string GenerateIdToken()
        {
            using RSA provider = RSA.Create(2048);

            RSAParameters parameters = provider.ExportParameters(true);

            RsaSecurityKey secKey = new RsaSecurityKey(parameters);

            SigningCredentials credentials = new SigningCredentials(secKey, "RS256");

            credentials.Key.KeyId = parameters.ToString();

            var header = new JwtHeader(credentials)
            {
                { "jku", "https://e0d67c509fb203858ebcb2fe3f88c2aa.baas.nintendo.com/1.0.0/certificates" }
            };

            byte[] rawUserId = new byte[0x10];
            RandomNumberGenerator.Fill(rawUserId);

            byte[] deviceId = new byte[0x10];
            RandomNumberGenerator.Fill(deviceId);

            byte[] deviceAccountId = new byte[0x10];
            RandomNumberGenerator.Fill(deviceId);

            var payload = new JwtPayload
            {
                { "sub", BitConverter.ToString(rawUserId).Replace("-", "").ToLower() },
                { "aud", "ed9e2f05d286f7b8" },
                { "di", BitConverter.ToString(deviceId).Replace("-", "").ToLower() },
                { "sn", "XAW10000000000" },
                { "bs:did", BitConverter.ToString(deviceAccountId).Replace("-", "").ToLower() },
                { "iss", "https://e0d67c509fb203858ebcb2fe3f88c2aa.baas.nintendo.com" },
                { "typ", "id_token" },
                { "iat", DateTimeOffset.UtcNow.ToUnixTimeSeconds() },
                { "jti", Guid.NewGuid().ToString() },
                { "exp", (DateTimeOffset.UtcNow + TimeSpan.FromHours(3)).ToUnixTimeSeconds() }
            };

            JwtSecurityToken securityToken = new JwtSecurityToken(header, payload);

            return new JwtSecurityTokenHandler().WriteToken(securityToken);
        }

        public ResultCode CheckAvailability(ServiceCtx context)
        {
            // NOTE: This opens the file at "su/baas/USERID_IN_UUID_STRING.dat" where USERID_IN_UUID_STRING is formatted as "%08x-%04x-%04x-%02x%02x-%08x%04x".
            //       Then it searches the Availability of Online Services related to the UserId in this file and returns it.

            Logger.Stub?.PrintStub(LogClass.ServiceAcc);

            // NOTE: Even if we try to return different error codes here, the guest still needs other calls.
            return ResultCode.Success;
        }

        public ResultCode GetAccountId(ServiceCtx context)
        {
            // NOTE: This opens the file at "su/baas/USERID_IN_UUID_STRING.dat" (where USERID_IN_UUID_STRING is formatted
            //       as "%08x-%04x-%04x-%02x%02x-%08x%04x") in the account:/ savedata.
            //       Then it searches the NetworkServiceAccountId related to the UserId in this file and returns it.

            Logger.Stub?.PrintStub(LogClass.ServiceAcc, new { NetworkServiceAccountId });

            context.ResponseData.Write(NetworkServiceAccountId);

            return ResultCode.Success;
        }

        public ResultCode EnsureIdTokenCacheAsync(ServiceCtx context, out IAsyncContext asyncContext)
        {
            KEvent         asyncEvent     = new KEvent(context.Device.System.KernelContext);
            AsyncExecution asyncExecution = new AsyncExecution(asyncEvent);

            asyncExecution.Initialize(1000, EnsureIdTokenCacheAsyncImpl);

            asyncContext = new IAsyncContext(asyncExecution);

            // return ResultCode.NullObject if the IAsyncContext pointer is null. Doesn't occur in our case.

            return ResultCode.Success;
        }

        private async Task EnsureIdTokenCacheAsyncImpl(CancellationToken token)
        {
            // NOTE: This open the file at "su/baas/USERID_IN_UUID_STRING.dat" (where USERID_IN_UUID_STRING is formatted as "%08x-%04x-%04x-%02x%02x-%08x%04x")
            //       in the "account:/" savedata.
            //       Then its read data, use dauth API with this data to get the Token Id and probably store the dauth response
            //       in "su/cache/USERID_IN_UUID_STRING.dat" (where USERID_IN_UUID_STRING is formatted as "%08x-%04x-%04x-%02x%02x-%08x%04x") in the "account:/" savedata.
            //       Since we don't support online services, we can stub it.

            Logger.Stub?.PrintStub(LogClass.ServiceAcc);

            // TODO: Use a real function instead, with the CancellationToken.
            await Task.CompletedTask;
        }

        public ResultCode LoadIdTokenCache(ServiceCtx context)
        {
            ulong bufferPosition = context.Request.ReceiveBuff[0].Position;
            ulong bufferSize     = context.Request.ReceiveBuff[0].Size;

            // NOTE: This opens the file at "su/cache/USERID_IN_UUID_STRING.dat" (where USERID_IN_UUID_STRING is formatted as "%08x-%04x-%04x-%02x%02x-%08x%04x")
            //       in the "account:/" savedata and writes some data in the buffer.
            //       Since we don't support online services, we can stub it.

            Logger.Stub?.PrintStub(LogClass.ServiceAcc);

            /*
            if (internal_object != null)
            {
                if (bufferSize > 0xC00)
                {
                    return ResultCode.InvalidIdTokenCacheBufferSize;
                }
            }
            */

            byte[] tokenData = Encoding.ASCII.GetBytes(GenerateIdToken());

            context.Memory.Write(bufferPosition, tokenData);
            context.ResponseData.Write(tokenData.Length);

            return ResultCode.Success;
        }

        public ResultCode GetNintendoAccountUserResourceCacheForApplication(ServiceCtx context)
        {
            Logger.Stub?.PrintStub(LogClass.ServiceAcc, new { NetworkServiceAccountId });

            context.ResponseData.Write(NetworkServiceAccountId);

            // TODO: determine and fill the output IPC buffer.

            return ResultCode.Success;
        }

        public ResultCode StoreOpenContext(ServiceCtx context)
        {
            Logger.Stub?.PrintStub(LogClass.ServiceAcc);

            return ResultCode.Success;
        }
    }
}