using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;
using BTCPayServer.Abstractions.Constants;
using BTCPayServer.Client;
using BTCPayServer.Client.Models;
using BTCPayServer.Data;
using BTCPayServer.Filters;
using BTCPayServer.Models.PaymentRequestViewModels;
using BTCPayServer.PaymentRequest;
using BTCPayServer.Services.Invoices;
using BTCPayServer.Services.PaymentRequests;
using BTCPayServer.Services.Rates;
using BTCPayServer.Services.Stores;
using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.Identity;
using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Routing;
using PaymentRequestData = BTCPayServer.Data.PaymentRequestData;
using StoreData = BTCPayServer.Data.StoreData;

namespace BTCPayServer.Controllers
{
    [Authorize(Policy = Policies.CanModifyStoreSettings, AuthenticationSchemes = AuthenticationSchemes.Cookie)]
    [Route("payment-requests")]
    public class PaymentRequestController : Controller
    {
        private readonly InvoiceController _InvoiceController;
        private readonly UserManager<ApplicationUser> _UserManager;
        private readonly StoreRepository _StoreRepository;
        private readonly PaymentRequestRepository _PaymentRequestRepository;
        private readonly PaymentRequestService _PaymentRequestService;
        private readonly EventAggregator _EventAggregator;
        private readonly CurrencyNameTable _Currencies;
        private readonly InvoiceRepository _InvoiceRepository;
        private readonly LinkGenerator _linkGenerator;

        public PaymentRequestController(
            InvoiceController invoiceController,
            UserManager<ApplicationUser> userManager,
            StoreRepository storeRepository,
            PaymentRequestRepository paymentRequestRepository,
            PaymentRequestService paymentRequestService,
            EventAggregator eventAggregator,
            CurrencyNameTable currencies,
            InvoiceRepository invoiceRepository,
            LinkGenerator linkGenerator)
        {
            _InvoiceController = invoiceController;
            _UserManager = userManager;
            _StoreRepository = storeRepository;
            _PaymentRequestRepository = paymentRequestRepository;
            _PaymentRequestService = paymentRequestService;
            _EventAggregator = eventAggregator;
            _Currencies = currencies;
            _InvoiceRepository = invoiceRepository;
            _linkGenerator = linkGenerator;
        }

        [BitpayAPIConstraint(false)]
        [HttpGet("/stores/{storeId}/payment-requests")]
        public async Task<IActionResult> GetPaymentRequests(string storeId, ListPaymentRequestsViewModel model = null)
        {
            model = this.ParseListQuery(model ?? new ListPaymentRequestsViewModel());

            var includeArchived = new SearchString(model.SearchTerm).GetFilterBool("includearchived") == true;
            var result = await _PaymentRequestRepository.FindPaymentRequests(new PaymentRequestQuery
            {
                UserId = GetUserId(),
                StoreId = CurrentStore.Id,
                Skip = model.Skip,
                Count = model.Count,
                IncludeArchived = includeArchived
            });

            model.Total = result.Total;
            model.Items = result.Items.Select(data => new ViewPaymentRequestViewModel(data)).ToList();
            return View(model);
        }

        [HttpGet("/stores/{storeId}/payment-requests/edit/{payReqId?}")]
        public async Task<IActionResult> EditPaymentRequest(string storeId, string payReqId)
        {
            var data = await _PaymentRequestRepository.FindPaymentRequest(payReqId, GetUserId());
            if (data == null && !string.IsNullOrEmpty(payReqId))
            {
                return NotFound();
            }

            return View(nameof(EditPaymentRequest), new UpdatePaymentRequestViewModel(data)
            {
                StoreId = CurrentStore.Id
            });
        }

        [HttpPost("/stores/{storeId}/payment-requests/edit/{payReqId?}")]
        public async Task<IActionResult> EditPaymentRequest(string payReqId, UpdatePaymentRequestViewModel viewModel)
        {
            if (string.IsNullOrEmpty(viewModel.Currency) ||
                _Currencies.GetCurrencyData(viewModel.Currency, false) == null)
                ModelState.AddModelError(nameof(viewModel.Currency), "Invalid currency");

            var data = await _PaymentRequestRepository.FindPaymentRequest(payReqId, GetUserId());
            if (data == null && !string.IsNullOrEmpty(payReqId))
            {
                return NotFound();
            }

            if (data?.Archived is true && viewModel.Archived is true)
            {
                ModelState.AddModelError(string.Empty, "You cannot edit an archived payment request.");
            }

            if (!ModelState.IsValid)
            {
                return View(nameof(EditPaymentRequest), viewModel);
            }

            if (data == null)
            {
                data = new PaymentRequestData();
            }

            data.StoreDataId = viewModel.StoreId;
            data.Archived = viewModel.Archived;
            var blob = data.GetBlob();

            blob.Title = viewModel.Title;
            blob.Email = viewModel.Email;
            blob.Description = viewModel.Description;
            blob.Amount = viewModel.Amount;
            blob.ExpiryDate = viewModel.ExpiryDate?.ToUniversalTime();
            blob.Currency = viewModel.Currency;
            blob.EmbeddedCSS = viewModel.EmbeddedCSS;
            blob.CustomCSSLink = viewModel.CustomCSSLink;
            blob.AllowCustomPaymentAmounts = viewModel.AllowCustomPaymentAmounts;

            data.SetBlob(blob);
            if (string.IsNullOrEmpty(payReqId))
            {
                data.Created = DateTimeOffset.UtcNow;
            }

            data = await _PaymentRequestRepository.CreateOrUpdatePaymentRequest(data);
            _EventAggregator.Publish(new PaymentRequestUpdated { Data = data, PaymentRequestId = data.Id, });

            TempData[WellKnownTempData.SuccessMessage] = "Saved";
            return RedirectToAction(nameof(EditPaymentRequest), new { storeId = CurrentStore.Id, payReqId = data.Id });
        }

        [HttpGet("{payReqId}")]
        [AllowAnonymous]
        public async Task<IActionResult> ViewPaymentRequest(string payReqId)
        {
            var result = await _PaymentRequestService.GetPaymentRequest(payReqId, GetUserId());
            if (result == null)
            {
                return NotFound();
            }

            result.HubPath = PaymentRequestHub.GetHubPath(Request);
            return View(result);
        }

        [HttpGet("{payReqId}/pay")]
        [AllowAnonymous]
        public async Task<IActionResult> PayPaymentRequest(string payReqId, bool redirectToInvoice = true,
            decimal? amount = null, CancellationToken cancellationToken = default)
        {
            if (amount.HasValue && amount.Value <= 0)
            {
                return BadRequest("Please provide an amount greater than 0");
            }

            var result = await _PaymentRequestService.GetPaymentRequest(payReqId, GetUserId());
            if (result == null)
            {
                return NotFound();
            }

            if (result.Archived)
            {
                if (redirectToInvoice)
                {
                    return RedirectToAction("ViewPaymentRequest", new { Id = payReqId });
                }

                return BadRequest("Payment Request cannot be paid as it has been archived");
            }

            result.HubPath = PaymentRequestHub.GetHubPath(Request);
            if (result.AmountDue <= 0)
            {
                if (redirectToInvoice)
                {
                    return RedirectToAction("ViewPaymentRequest", new { Id = payReqId });
                }

                return BadRequest("Payment Request has already been settled.");
            }

            if (result.ExpiryDate.HasValue && DateTime.UtcNow >= result.ExpiryDate)
            {
                if (redirectToInvoice)
                {
                    return RedirectToAction("ViewPaymentRequest", new { Id = payReqId });
                }

                return BadRequest("Payment Request has expired");
            }

            var stateAllowedToDisplay = new HashSet<InvoiceState>
            {
                new InvoiceState(InvoiceStatusLegacy.New, InvoiceExceptionStatus.None),
                new InvoiceState(InvoiceStatusLegacy.New, InvoiceExceptionStatus.PaidPartial),
            };
            var currentInvoice = result
                .Invoices
                .FirstOrDefault(invoice => stateAllowedToDisplay.Contains(invoice.State));
            if (currentInvoice != null)
            {
                if (redirectToInvoice)
                {
                    return RedirectToAction("Checkout", "Invoice", new { currentInvoice.Id });
                }

                return Ok(currentInvoice.Id);
            }

            if (result.AllowCustomPaymentAmounts && amount != null)
                amount = Math.Min(result.AmountDue, amount.Value);
            else
                amount = result.AmountDue;
            
            var pr = await _PaymentRequestRepository.FindPaymentRequest(payReqId, null, cancellationToken);
            var blob = pr.GetBlob();
            var store = pr.StoreData;
            try
            {
                var redirectUrl = _linkGenerator.PaymentRequestLink(payReqId, Request.Scheme, Request.Host, Request.PathBase);

                var invoiceMetadata =
                    new InvoiceMetadata
                    {
                        OrderId = PaymentRequestRepository.GetOrderIdForPaymentRequest(payReqId),
                        PaymentRequestId = payReqId,
                        BuyerEmail = result.Email
                    };

                var invoiceRequest =
                    new CreateInvoiceRequest
                    {
                        Metadata = invoiceMetadata.ToJObject(),
                        Currency = blob.Currency,
                        Amount = amount.Value,
                        Checkout = {RedirectURL = redirectUrl}
                    };

                var additionalTags = new List<string> {PaymentRequestRepository.GetInternalTag(payReqId)};
                var newInvoice = await _InvoiceController.CreateInvoiceCoreRaw(invoiceRequest,store, Request.GetAbsoluteRoot(), additionalTags, cancellationToken);

                if (redirectToInvoice)
                {
                    return RedirectToAction("Checkout", "Invoice", new { newInvoice.Id });
                }

                return Ok(newInvoice.Id);
            }
            catch (BitpayHttpException e)
            {
                return BadRequest(e.Message);
            }
        }

        [HttpGet("{payReqId}/cancel")]
        public async Task<IActionResult> CancelUnpaidPendingInvoice(string payReqId, bool redirect = true)
        {
            var result = await _PaymentRequestService.GetPaymentRequest(payReqId, GetUserId());
            if (result == null)
            {
                return NotFound();
            }

            if (!result.AllowCustomPaymentAmounts) {
                return BadRequest("Not allowed to cancel this invoice");
            }

            var invoices = result.Invoices.Where(requestInvoice =>
                requestInvoice.State.Status == InvoiceStatusLegacy.New && !requestInvoice.Payments.Any());

            if (!invoices.Any())
            {
                return BadRequest("No unpaid pending invoice to cancel");
            }

            foreach (var invoice in invoices)
            {
                await _InvoiceRepository.MarkInvoiceStatus(invoice.Id, InvoiceStatus.Invalid);
            }

            if (redirect)
            {
                TempData[WellKnownTempData.SuccessMessage] = "Payment cancelled";
                return RedirectToAction(nameof(ViewPaymentRequest), new { Id = payReqId });
            }

            return Ok("Payment cancelled");
        }

        [HttpGet("{payReqId}/clone")]
        public async Task<IActionResult> ClonePaymentRequest(string payReqId)
        {
            var result = await EditPaymentRequest(CurrentStore.Id, payReqId);
            if (result is ViewResult viewResult)
            {
                var model = (UpdatePaymentRequestViewModel)viewResult.Model;
                model.Id = null;
                model.Archived = false;
                model.ExpiryDate = null;
                model.Title = $"Clone of {model.Title}";
                return View("EditPaymentRequest", model);
            }

            return NotFound();
        }

        [HttpGet("{payReqId}/archive")]
        public async Task<IActionResult> TogglePaymentRequestArchival(string payReqId)
        {
            var result = await EditPaymentRequest(CurrentStore.Id, payReqId);
            if (result is ViewResult viewResult)
            {
                var model = (UpdatePaymentRequestViewModel)viewResult.Model;
                model.Archived = !model.Archived;
                await EditPaymentRequest(payReqId, model);
                TempData[WellKnownTempData.SuccessMessage] = model.Archived
                    ? "The payment request has been archived and will no longer appear in the  payment request list by default again."
                    : "The payment request has been unarchived and will appear in the  payment request list by default.";
                return RedirectToAction("GetPaymentRequests");
            }

            return NotFound();
        }

        private string GetUserId()
        {
            return _UserManager.GetUserId(User);
        }
        
        private StoreData CurrentStore
        {
            get => HttpContext.GetStoreData();
        }
    }
}