using BTCPayServer.Data;
using BTCPayServer.Filters;
using BTCPayServer.Models.InvoicingModels;
using BTCPayServer.Services.Invoices;
using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.Cors;
using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Mvc.Rendering;
using NBitcoin;
using NBitpayClient;
using System;
using System.Collections.Generic;
using System.Globalization;
using System.Linq;
using System.Security.Claims;
using System.Text;
using System.Threading.Tasks;
using BTCPayServer.Services.Rates;
using System.Net.WebSockets;
using System.Threading;
using BTCPayServer.Events;

namespace BTCPayServer.Controllers
{
    public partial class InvoiceController
    {
        [HttpPost]
        [Route("invoices/{invoiceId}")]
        public IActionResult Invoice(string invoiceId, string command, string cryptoCode = null)
        {
            if (command == "refresh")
            {
                _Watcher.Watch(invoiceId);
            }
            StatusMessage = "Invoice is state is being refreshed, please refresh the page soon...";
            return RedirectToAction(nameof(Invoice), new
            {
                invoiceId = invoiceId
            });
        }

        [HttpGet]
        [Route("invoices/{invoiceId}")]
        public async Task<IActionResult> Invoice(string invoiceId, string cryptoCode = null)
        {
            if (cryptoCode == null)
                cryptoCode = "BTC";
            var invoice = (await _InvoiceRepository.GetInvoices(new InvoiceQuery()
            {
                UserId = GetUserId(),
                InvoiceId = invoiceId
            })).FirstOrDefault();
            if (invoice == null)
                return NotFound();

            var network = _NetworkProvider.GetNetwork(cryptoCode);
            if (network == null || !invoice.Support(network))
                return NotFound();

            var cryptoData = invoice.GetCryptoData(network);

            var dto = invoice.EntityToDTO(_NetworkProvider);
            var cryptoInfo = dto.CryptoInfo.First(o => o.CryptoCode.Equals(cryptoCode, StringComparison.OrdinalIgnoreCase));
            var store = await _StoreRepository.FindStore(invoice.StoreId);

            var accounting = cryptoData.Calculate();
            InvoiceDetailsModel model = new InvoiceDetailsModel()
            {
                StoreName = store.StoreName,
                StoreLink = Url.Action(nameof(StoresController.UpdateStore), "Stores", new { storeId = store.Id }),
                Id = invoice.Id,
                Status = invoice.Status,
                RefundEmail = invoice.RefundMail,
                CreatedDate = invoice.InvoiceTime,
                ExpirationDate = invoice.ExpirationTime,
                OrderId = invoice.OrderId,
                BuyerInformation = invoice.BuyerInformation,
                Rate = cryptoData.Rate,
                Fiat = dto.Price + " " + dto.Currency,
                BTC = accounting.TotalDue.ToString() + $" {network.CryptoCode}",
                BTCDue = accounting.Due.ToString() + $" {network.CryptoCode}",
                BTCPaid = accounting.Paid.ToString() + $" {network.CryptoCode}",
                NetworkFee = accounting.NetworkFee.ToString() + $" {network.CryptoCode}",
                NotificationUrl = invoice.NotificationURL,
                ProductInformation = invoice.ProductInformation,
                BitcoinAddress = BitcoinAddress.Create(cryptoInfo.Address, network.NBitcoinNetwork),
                PaymentUrl = cryptoInfo.PaymentUrls.BIP72
            };

            var payments = invoice
                .Payments
                .Select(async payment =>
                {
                    var m = new InvoiceDetailsModel.Payment();
                    m.DepositAddress = payment.GetScriptPubKey().GetDestinationAddress(network.NBitcoinNetwork);
                    m.Confirmations = (await _Explorer.GetTransactionAsync(payment.Outpoint.Hash))?.Confirmations ?? 0;
                    m.TransactionId = payment.Outpoint.Hash.ToString();
                    m.ReceivedTime = payment.ReceivedTime;
                    m.TransactionLink = string.Format(network.BlockExplorerLink, m.TransactionId);
                    return m;
                })
                .ToArray();
            await Task.WhenAll(payments);
            model.Payments = payments.Select(p => p.GetAwaiter().GetResult()).ToList();
            model.StatusMessage = StatusMessage;
            return View(model);
        }

        [HttpGet]
        [Route("i/{invoiceId}")]
        [Route("invoice")]
        [AcceptMediaTypeConstraint("application/bitcoin-paymentrequest", false)]
        [XFrameOptionsAttribute(null)]
        public async Task<IActionResult> Checkout(string invoiceId, string id = null, string cryptoCode = null)
        {
            if (cryptoCode == null)
                cryptoCode = "BTC";
            //Keep compatibility with Bitpay
            invoiceId = invoiceId ?? id;
            id = invoiceId;
            ////

            var model = await GetInvoiceModel(invoiceId, cryptoCode);
            if (model == null)
                return NotFound();

            return View(nameof(Checkout), model);
        }

        private async Task<PaymentModel> GetInvoiceModel(string invoiceId, string cryptoCode)
        {
            if (cryptoCode == null)
                throw new ArgumentNullException(nameof(cryptoCode));
            var invoice = await _InvoiceRepository.GetInvoice(null, invoiceId);
            var network = _NetworkProvider.GetNetwork(cryptoCode);
            if (invoice == null || network == null || !invoice.Support(network))
                return null;

            var cryptoData = invoice.GetCryptoData(network);
            var store = await _StoreRepository.FindStore(invoice.StoreId);
            var dto = invoice.EntityToDTO(_NetworkProvider);
            var cryptoInfo = dto.CryptoInfo.First(o => o.CryptoCode == network.CryptoCode);
            var currency = invoice.ProductInformation.Currency;
            var accounting = cryptoData.Calculate();
            var model = new PaymentModel()
            {
                ServerUrl = HttpContext.Request.GetAbsoluteRoot(),
                OrderId = invoice.OrderId,
                InvoiceId = invoice.Id,
                BtcAddress = cryptoData.DepositAddress,
                BtcAmount = (accounting.TotalDue - cryptoData.TxFee).ToString(),
                BtcTotalDue = accounting.TotalDue.ToString(),
                BtcDue = accounting.Due.ToString(),
                CustomerEmail = invoice.RefundMail,
                ExpirationSeconds = Math.Max(0, (int)(invoice.ExpirationTime - DateTimeOffset.UtcNow).TotalSeconds),
                MaxTimeSeconds = (int)(invoice.ExpirationTime - invoice.InvoiceTime).TotalSeconds,
                ItemDesc = invoice.ProductInformation.ItemDesc,
                Rate = cryptoData.Rate.ToString("C", _CurrencyNameTable.GetCurrencyProvider(currency)) + $" ({currency})",
                MerchantRefLink = invoice.RedirectURL ?? "/",
                StoreName = store.StoreName,
                TxFees = cryptoData.TxFee.ToString(),
                InvoiceBitcoinUrl = cryptoInfo.PaymentUrls.BIP21,
                TxCount = accounting.TxCount,
                BtcPaid = accounting.Paid.ToString(),
                Status = invoice.Status
            };

            var expiration = TimeSpan.FromSeconds(model.ExpirationSeconds);
            model.TimeLeft = PrettyPrint(expiration);
            return model;
        }

        private string PrettyPrint(TimeSpan expiration)
        {
            StringBuilder builder = new StringBuilder();
            if (expiration.Days >= 1)
                builder.Append(expiration.Days.ToString());
            if (expiration.Hours >= 1)
                builder.Append(expiration.Hours.ToString("00"));
            builder.Append($"{expiration.Minutes.ToString("00")}:{expiration.Seconds.ToString("00")}");
            return builder.ToString();
        }

        [HttpGet]
        [Route("i/{invoiceId}/status")]
        public async Task<IActionResult> GetStatus(string invoiceId, string cryptoCode)
        {
            if (cryptoCode == null)
                cryptoCode = "BTC";
            var model = await GetInvoiceModel(invoiceId, cryptoCode);
            if (model == null)
                return NotFound();
            return Json(model);
        }

        [HttpGet]
        [Route("i/{invoiceId}/status/ws")]
        public async Task<IActionResult> GetStatusWebSocket(string invoiceId)
        {
            if (!HttpContext.WebSockets.IsWebSocketRequest)
                return NotFound();
            var invoice = await _InvoiceRepository.GetInvoice(null, invoiceId);
            if (invoice == null || invoice.Status == "complete" || invoice.Status == "invalid" || invoice.Status == "expired")
                return NotFound();
            var webSocket = await HttpContext.WebSockets.AcceptWebSocketAsync();
            CompositeDisposable leases = new CompositeDisposable();
            try
            {
                _EventAggregator.Subscribe<Events.InvoiceDataChangedEvent>(async o => await NotifySocket(webSocket, o.InvoiceId, invoiceId));
                _EventAggregator.Subscribe<Events.InvoicePaymentEvent>(async o => await NotifySocket(webSocket, o.InvoiceId, invoiceId));
                _EventAggregator.Subscribe<Events.InvoiceStatusChangedEvent>(async o => await NotifySocket(webSocket, o.InvoiceId, invoiceId));
                while (true)
                {
                    var message = await webSocket.ReceiveAsync(DummyBuffer, default(CancellationToken));
                    if (message.MessageType == WebSocketMessageType.Close)
                        break;
                }
            }
            finally
            {
                leases.Dispose();
                await CloseSocket(webSocket);
            }
            return new EmptyResult();
        }
        
        ArraySegment<Byte> DummyBuffer = new ArraySegment<Byte>(new Byte[1]);
        private async Task NotifySocket(WebSocket webSocket, string invoiceId, string expectedId)
        {
            if (invoiceId != expectedId || webSocket.State != WebSocketState.Open)
                return;
            CancellationTokenSource cts = new CancellationTokenSource();
            cts.CancelAfter(5000);
            try
            {
                await webSocket.SendAsync(DummyBuffer, WebSocketMessageType.Binary, true, cts.Token);
            }
            catch { await CloseSocket(webSocket); }
        }

        private static async Task CloseSocket(WebSocket webSocket)
        {
            try
            {
                if (webSocket.State == WebSocketState.Open)
                {
                    CancellationTokenSource cts = new CancellationTokenSource();
                    cts.CancelAfter(5000);
                    await webSocket.CloseAsync(WebSocketCloseStatus.NormalClosure, "Closing", cts.Token);
                }
            }
            catch { }
            finally { webSocket.Dispose(); }
        }

        [HttpPost]
        [Route("i/{invoiceId}/UpdateCustomer")]
        public async Task<IActionResult> UpdateCustomer(string invoiceId, [FromBody]UpdateCustomerModel data)
        {
            if (!ModelState.IsValid)
            {
                return BadRequest(ModelState);
            }
            await _InvoiceRepository.UpdateInvoice(invoiceId, data).ConfigureAwait(false);
            return Ok();
        }

        [HttpGet]
        [Route("invoices")]
        [Authorize(AuthenticationSchemes = "Identity.Application")]
        [BitpayAPIConstraint(false)]
        public async Task<IActionResult> ListInvoices(string searchTerm = null, int skip = 0, int count = 20)
        {
            var model = new InvoicesModel();
            var filterString = new SearchString(searchTerm);
            foreach (var invoice in await _InvoiceRepository.GetInvoices(new InvoiceQuery()
            {
                TextSearch = filterString.TextSearch,
                Count = count,
                Skip = skip,
                UserId = GetUserId(),
                Status = filterString.Filters.TryGet("status"),
                StoreId = filterString.Filters.TryGet("storeid")
            }))
            {
                model.SearchTerm = searchTerm;
                model.Invoices.Add(new InvoiceModel()
                {
                    Status = invoice.Status,
                    Date = invoice.InvoiceTime,
                    InvoiceId = invoice.Id,
                    AmountCurrency = $"{invoice.ProductInformation.Price.ToString(CultureInfo.InvariantCulture)} {invoice.ProductInformation.Currency}"
                });
            }
            model.Skip = skip;
            model.Count = count;
            model.StatusMessage = StatusMessage;
            return View(model);
        }

        [HttpGet]
        [Route("invoices/create")]
        [Authorize(AuthenticationSchemes = "Identity.Application")]
        [BitpayAPIConstraint(false)]
        public async Task<IActionResult> CreateInvoice()
        {
            var stores = await GetStores(GetUserId());
            if (stores.Count() == 0)
            {
                StatusMessage = "Error: You need to create at least one store before creating a transaction";
                return RedirectToAction(nameof(StoresController.ListStores), "Stores");
            }
            return View(new CreateInvoiceModel() { Stores = stores });
        }

        [HttpPost]
        [Route("invoices/create")]
        [Authorize(AuthenticationSchemes = "Identity.Application")]
        [BitpayAPIConstraint(false)]
        public async Task<IActionResult> CreateInvoice(CreateInvoiceModel model)
        {
            model.Stores = await GetStores(GetUserId(), model.StoreId);
            if (!ModelState.IsValid)
            {
                return View(model);
            }
            var store = await _StoreRepository.FindStore(model.StoreId, GetUserId());
            if (store.GetDerivationStrategies(_NetworkProvider).Count() == 0)
            {
                StatusMessage = "Error: You need to configure the derivation scheme in order to create an invoice";
                return RedirectToAction(nameof(StoresController.UpdateStore), "Stores", new
                {
                    storeId = store.Id
                });
            }

            try
            {
                var result = await CreateInvoiceCore(new Invoice()
                {
                    Price = model.Amount.Value,
                    Currency = model.Currency,
                    PosData = model.PosData,
                    OrderId = model.OrderId,
                    //RedirectURL = redirect + "redirect",
                    NotificationURL = model.NotificationUrl,
                    ItemDesc = model.ItemDesc,
                    FullNotifications = true,
                    BuyerEmail = model.BuyerEmail,
                }, store, HttpContext.Request.GetAbsoluteRoot());

                StatusMessage = $"Invoice {result.Data.Id} just created!";
                return RedirectToAction(nameof(ListInvoices));
            }
            catch (RateUnavailableException)
            {
                ModelState.TryAddModelError(nameof(model.Currency), "Unsupported currency");
                return View(model);
            }
        }

        private async Task<SelectList> GetStores(string userId, string storeId = null)
        {
            return new SelectList(await _StoreRepository.GetStoresByUserId(userId), nameof(StoreData.Id), nameof(StoreData.StoreName), storeId);
        }

        [HttpPost]
        [Authorize(AuthenticationSchemes = "Identity.Application")]
        [BitpayAPIConstraint(false)]
        public IActionResult SearchInvoice(InvoicesModel invoices)
        {
            return RedirectToAction(nameof(ListInvoices), new
            {
                searchTerm = invoices.SearchTerm,
                skip = invoices.Skip,
                count = invoices.Count,
            });
        }

        [HttpPost]
        [Route("invoices/invalidatepaid")]
        [Authorize(AuthenticationSchemes = "Identity.Application")]
        [BitpayAPIConstraint(false)]
        public async Task<IActionResult> InvalidatePaidInvoice(string invoiceId)
        {
            await _InvoiceRepository.UpdatePaidInvoiceToInvalid(invoiceId);
            return RedirectToAction(nameof(ListInvoices));
        }

        [TempData]
        public string StatusMessage
        {
            get;
            set;
        }

        private string GetUserId()
        {
            return _UserManager.GetUserId(User);
        }
    }
}