using Fitness_core_BE.Exceptions;
using Fitness_core_BE.Interfaces;
using Fitness_core_BE.Interfaces.Services;
using Fitness_core_BE.Models;
using Fitness_core_BE.Models.Receipt;
using QuestPDF.Fluent;
using QuestPDF.Helpers;
using QuestPDF.Infrastructure;

namespace Fitness_core_BE.Services
{
    public class ReceiptService : IReceiptService
    {
        private readonly ICustomerInvoiceRepository _customerInvoiceRepository;
        private readonly ICustomerSubscriptionRepository _customerSubscriptionRepository;
        private readonly IClientRepository _clientRepository;
        private readonly IClientInvoiceRepository _clientInvoiceRepository;
        private readonly IPaymentRepository _paymentRepository;
        private readonly IThirdPartyService _thirdPartyService;

        public ReceiptService(
            ICustomerInvoiceRepository customerInvoiceRepository,
            ICustomerSubscriptionRepository customerSubscriptionRepository,
            IClientRepository clientRepository,
            IClientInvoiceRepository clientInvoiceRepository,
            IPaymentRepository paymentRepository,
            IThirdPartyService thirdPartyService)
        {
            _customerInvoiceRepository = customerInvoiceRepository;
            _customerSubscriptionRepository = customerSubscriptionRepository;
            _clientRepository = clientRepository;
            _clientInvoiceRepository = clientInvoiceRepository;
            _paymentRepository = paymentRepository;
            _thirdPartyService = thirdPartyService;
        }

        public async Task<ReceiptModel> BuildForInvoiceAsync(Guid customerInvoiceId, decimal? paymentAmount = null, Guid? requireClientId = null)
        {
            var invoice = await _customerInvoiceRepository.GetCustomerInvoiceById(customerInvoiceId)
                ?? throw new NotFoundException("Invoice not found");

            if (requireClientId.HasValue && invoice.FKClientId != requireClientId.Value)
                throw new UnauthorizedException("This invoice does not belong to your gym.");

            var subscription = await _customerSubscriptionRepository.GetCustomerSubscriptionById(invoice.FKCustomerSubscriptionId);
            string planName = subscription?.CustomerPlan?.PlanName ?? "Membership";
            Guid? customerId = subscription?.FKCustomerId;

            Customer? customer = customerId.HasValue ? await _clientRepository.GetCustomerById(customerId.Value) : null;
            var client = await _clientRepository.GetClientByIdAsync(invoice.FKClientId);
            string gymName = client?.ClientBusinesses?.FirstOrDefault()?.BusinessName
                             ?? client?.ClientName
                             ?? "GYM OS";

            decimal paid = await _paymentRepository.GetApprovedPaidAmountAsync(customerInvoiceId);

            return new ReceiptModel
            {
                ClientId = invoice.FKClientId,
                ReceiptNo = $"GYMOS-{customerInvoiceId.ToString("N")[..8].ToUpperInvariant()}",
                Date = DateTime.UtcNow,
                GymName = gymName,
                MemberName = customer?.CusName ?? "Member",
                MemberPhone = customer?.PrimaryPH,
                MemberEmail = customer?.Email,
                PlanName = planName,
                AmountPaid = paymentAmount ?? paid,
                InvoiceAmount = invoice.Amount,
                Balance = invoice.Amount - paid,
                Currency = "LKR"
            };
        }

        public async Task<ReceiptModel> BuildForClientInvoiceAsync(Guid clientInvoiceId, decimal? paymentAmount = null, Guid? requireClientId = null)
        {
            var invoice = await _clientInvoiceRepository.GetClientInvoiceById(clientInvoiceId)
                ?? throw new NotFoundException("Invoice not found");

            var clientId = invoice.ClientSubscription?.FKClientId ?? Guid.Empty;
            if (requireClientId.HasValue && clientId != requireClientId.Value)
                throw new UnauthorizedException("This invoice does not belong to your gym.");

            var client = invoice.ClientSubscription?.Client ?? await _clientRepository.GetClientByIdAsync(clientId);
            string gymName = client?.ClientBusinesses?.FirstOrDefault()?.BusinessName
                             ?? client?.ClientName
                             ?? "Gym";

            var payments = await _paymentRepository.GetPaymentsByClientInvoiceIdAsync(clientInvoiceId);
            decimal paid = payments.Where(p => p.IsApproved == true).Sum(p => p.PayAmount);

            string itemSummary = invoice.Items?.FirstOrDefault()?.ItemName ?? "Platform fee";

            return new ReceiptModel
            {
                ClientId = clientId,
                ReceiptNo = $"HEXA-{clientInvoiceId.ToString("N")[..8].ToUpperInvariant()}",
                Date = DateTime.UtcNow,
                GymName = "HexaFitness",
                MemberName = gymName,
                MemberPhone = client?.ClientPhone,
                MemberEmail = client?.ClientEmail,
                PlanName = itemSummary,
                AmountPaid = paymentAmount ?? paid,
                InvoiceAmount = invoice.Amount,
                Balance = invoice.Amount - paid,
                Currency = "LKR"
            };
        }

        public byte[] GeneratePdf(ReceiptModel m)
        {
            string money(decimal v) => $"{m.Currency} {v:N2}";

            var document = QuestPDF.Fluent.Document.Create(container =>
            {
                container.Page(page =>
                {
                    page.Size(PageSizes.A5);
                    page.Margin(28);
                    page.DefaultTextStyle(x => x.FontSize(11).FontColor(Colors.Grey.Darken3));

                    page.Header().Column(col =>
                    {
                        col.Item().Text("GYM OS").FontSize(20).Bold().FontColor(Colors.Blue.Darken2);
                        col.Item().Text(m.GymName).FontSize(13).SemiBold();
                        col.Item().PaddingTop(2).Text("Payment Receipt").FontSize(10).FontColor(Colors.Grey.Medium);
                        col.Item().PaddingTop(6).LineHorizontal(1).LineColor(Colors.Grey.Lighten2);
                    });

                    page.Content().PaddingVertical(12).Column(col =>
                    {
                        col.Spacing(6);

                        col.Item().Row(row =>
                        {
                            row.RelativeItem().Text($"Receipt No: {m.ReceiptNo}");
                            row.RelativeItem().AlignRight().Text($"Date: {m.Date:yyyy-MM-dd}");
                        });

                        col.Item().PaddingTop(4).Text("Billed to").FontColor(Colors.Grey.Medium).FontSize(9);
                        col.Item().Text(m.MemberName).SemiBold();
                        if (!string.IsNullOrWhiteSpace(m.MemberPhone))
                            col.Item().Text(m.MemberPhone!).FontSize(10);
                        if (!string.IsNullOrWhiteSpace(m.MemberEmail))
                            col.Item().Text(m.MemberEmail!).FontSize(10);

                        col.Item().PaddingTop(10).Table(table =>
                        {
                            table.ColumnsDefinition(c =>
                            {
                                c.RelativeColumn(3);
                                c.RelativeColumn(2);
                            });

                            table.Cell().Element(HeaderCell).Text("Description");
                            table.Cell().Element(HeaderCell).AlignRight().Text("Amount");

                            table.Cell().Element(BodyCell).Text(m.PlanName);
                            table.Cell().Element(BodyCell).AlignRight().Text(money(m.AmountPaid));

                            static IContainer HeaderCell(IContainer c) =>
                                c.Background(Colors.Grey.Lighten3).PaddingVertical(5).PaddingHorizontal(8).DefaultTextStyle(t => t.SemiBold());
                            static IContainer BodyCell(IContainer c) =>
                                c.BorderBottom(1).BorderColor(Colors.Grey.Lighten2).PaddingVertical(5).PaddingHorizontal(8);
                        });

                        col.Item().PaddingTop(10).AlignRight().Column(totals =>
                        {
                            totals.Item().Text($"Amount paid: {money(m.AmountPaid)}").SemiBold();
                            totals.Item().Text($"Invoice total: {money(m.InvoiceAmount)}").FontSize(10).FontColor(Colors.Grey.Medium);
                            totals.Item().Text($"Balance due: {money(m.Balance)}").FontSize(10)
                                .FontColor(m.Balance > 0 ? Colors.Red.Medium : Colors.Green.Darken1);
                        });
                    });

                    page.Footer().AlignCenter().Column(col =>
                    {
                        col.Item().PaddingTop(6).LineHorizontal(1).LineColor(Colors.Grey.Lighten2);
                        col.Item().PaddingTop(6).Text("Thank you for your payment.").FontSize(10);
                        col.Item().Text($"{m.GymName} · powered by GYM OS").FontSize(8).FontColor(Colors.Grey.Medium);
                    });
                });
            });

            return document.GeneratePdf();
        }

        public async Task SendReceiptAsync(ReceiptModel m)
        {
            byte[] pdf;
            try
            {
                pdf = GeneratePdf(m);
            }
            catch (Exception ex)
            {
                Console.WriteLine($"Receipt PDF generation failed (non-critical): {ex.Message}");
                return;
            }

            if (!string.IsNullOrWhiteSpace(m.MemberEmail))
            {
                try
                {
                    string html =
                        $"<p>Hi {m.MemberName},</p>" +
                        $"<p>Thank you for your payment of <b>{m.Currency} {m.AmountPaid:N2}</b> for <b>{m.PlanName}</b> at {m.GymName}.</p>" +
                        (m.Balance > 0 ? $"<p>Outstanding balance: {m.Currency} {m.Balance:N2}.</p>" : "") +
                        $"<p>Your receipt ({m.ReceiptNo}) is attached.</p>" +
                        $"<p>— {m.GymName}<br/><small>powered by GYM OS</small></p>";
                    await _thirdPartyService.SendEmailAsync(m.MemberEmail!, $"Receipt {m.ReceiptNo} — {m.GymName}", html, pdf, $"{m.ReceiptNo}.pdf");
                }
                catch (Exception ex)
                {
                    Console.WriteLine($"Receipt email failed (non-critical): {ex.Message}");
                }
            }

            if (!string.IsNullOrWhiteSpace(m.MemberPhone))
            {
                try
                {
                    string sms = $"You paid {m.Currency} {m.AmountPaid:N2} for {m.PlanName} at {m.GymName}. Thank you! - GYM OS";
                    await _thirdPartyService.SendSmsAsync(m.MemberPhone!, null, sms);
                }
                catch (Exception ex)
                {
                    Console.WriteLine($"Receipt SMS failed (non-critical): {ex.Message}");
                }
            }
        }
    }
}