using Fitness_core_BE.Interfaces;
using Fitness_core_BE.Interfaces.Services;
using Fitness_core_BE.Models;
using Fitness_core_BE.Infra.UoW;
using System.Text.Json;
using Fitness_core_BE.Helpers;

namespace Fitness_core_BE.Services.CustomerInvoice
{
    public class CustomerInvoiceService : ICustomerInvoiceService
    {
        private readonly ICustomerInvoiceRepository _customerInvoiceRepository;
        private readonly IPaymentRepository _paymentRepository;
        private readonly IUnitOfWork _uow;
        private readonly UserRoleHelper _userRoleHelper;

        public CustomerInvoiceService(ICustomerInvoiceRepository customerInvoiceRepository, IPaymentRepository paymentRepository, IUnitOfWork uow, UserRoleHelper userRoleHelper)
        {
            _customerInvoiceRepository = customerInvoiceRepository;
            _paymentRepository = paymentRepository;
            _uow = uow;
            _userRoleHelper = userRoleHelper;
        }

        public async Task<object> CreateCustomerInvoiceFromSubscription(object payload, HttpContext httpContext)
        {
            await _uow.BeginAsync();
            try
            {
                var data = DeserializePayload.Deserialize(payload);
                
                if (!data!.ContainsKey("subscriptionId"))
                {
                    throw new KeyNotFoundException("subscriptionId is required");
                }

                var subscriptionId = Guid.Parse(data["subscriptionId"].GetString()!);
                var result = await _customerInvoiceRepository.CreateCustomerInvoiceFromSubscription(subscriptionId);
                await _uow.CommitAsync();
                
                return result;
            }
            catch
            {
                await _uow.RollbackAsync();
                throw;
            }
        }

        public async Task<object> GetCustomerInvoiceById(object payload, HttpContext httpContext)
        {
            var data = DeserializePayload.Deserialize(payload);
            
            if (!data!.ContainsKey("customerInvoiceId"))
            {
                throw new KeyNotFoundException("customerInvoiceId is required");
            }

            var customerInvoiceId = Guid.Parse(data["customerInvoiceId"].GetString()!);
            var customerInvoice = await _customerInvoiceRepository.GetCustomerInvoiceById(customerInvoiceId);

            if (customerInvoice == null)
            {
                throw new KeyNotFoundException("CustomerInvoice not found");
            }

            var paid = await _paymentRepository.GetApprovedPaidAmountAsync(customerInvoice.CustomerInvoiceId);
            var carriedForward = await _customerInvoiceRepository.GetCarriedForwardAmountsAsync(
                new List<Guid> { customerInvoice.CustomerInvoiceId });
            carriedForward.TryGetValue(customerInvoice.CustomerInvoiceId, out var carriedForwardAmount);

            var link = customerInvoice.CustomerSubscription?.TenantCustomerLink;
            return new
            {
                customerInvoice.CustomerInvoiceId,
                customerInvoice.FKCustomerSubscriptionId,
                customerInvoice.FKClientId,
                customerInvoice.FKUserId,
                customerInvoice.Amount,
                // The portion of Amount that's a prior cycle's unpaid balance rolled forward
                // (vs. this cycle's own charge) -- see SubscriptionRenewalRunner/BuildAndAddInvoice.
                CarriedForwardAmount = carriedForwardAmount,
                customerInvoice.Status,
                customerInvoice.CustomerInvoiceDate,
                PaidAmount = paid,
                Balance = customerInvoice.Amount - paid,
                // Flattened for callers that don't want to reach through
                // CustomerSubscription.TenantCustomerLink for basic display fields.
                CustomerName = link?.DisplayName,
                CustomerPhone = link?.PrimaryPhoneCached,
                customerInvoice.CustomerSubscription
            };
        }

        public async Task<object> GetCustomerInvoicesByCustomerId(object payload, HttpContext httpContext)
        {
            var data = DeserializePayload.Deserialize(payload);
            
            if (!data!.ContainsKey("customerId"))
            {
                throw new KeyNotFoundException("customerId is required");
            }

            var customerId = Guid.Parse(data["customerId"].GetString()!);
            var invoices = await _customerInvoiceRepository.GetCustomerInvoicesByCustomerId(customerId);

            // Same enriched shape as GetCustomerInvoicesByClientId -- this now backs a public
            // "view previous invoices" route the frontend renders as MemberInvoice rows.
            var result = new List<object>(invoices.Count);
            foreach (var invoice in invoices)
            {
                var paid = await _paymentRepository.GetApprovedPaidAmountAsync(invoice.CustomerInvoiceId);
                var link = invoice.CustomerSubscription?.TenantCustomerLink;
                result.Add(new
                {
                    invoice.CustomerInvoiceId,
                    invoice.FKCustomerSubscriptionId,
                    invoice.FKClientId,
                    invoice.Amount,
                    invoice.Status,
                    invoice.IsActive,
                    invoice.CustomerInvoiceDate,
                    PaidAmount = paid,
                    Balance = invoice.Amount - paid,
                    CustomerName = link?.DisplayName,
                    CustomerPhone = link?.PrimaryPhoneCached,
                    FKCustomerId = invoice.CustomerSubscription?.FKCustomerId,
                    invoice.CustomerSubscription
                });
            }
            return result;
        }

        public async Task<object> GetCustomerInvoicesByClientId(object payload, HttpContext httpContext)
        {
            Guid userId = DataExtractor.GetUserIdFromContext(httpContext);
            Guid clientId = await _userRoleHelper.GetClientId(userId);

            // scope=="latest": one row per customer (their latest approved invoice) instead of
            // every invoice they've ever had -- used by the regular invoices tab now that the
            // renewal-approval workflow can leave older invoices (Paid/RolledOver/Cancelled)
            // sitting alongside the current one. Default (no scope) keeps today's full-history
            // behavior for any other existing caller of this endpoint.
            var data = DeserializePayload.Deserialize(payload);
            var scope = data != null && data.ContainsKey("scope") ? data["scope"].GetString() : null;

            var invoices = scope == "latest"
                ? await _customerInvoiceRepository.GetLatestApprovedInvoicePerCustomerAsync(clientId)
                : await _customerInvoiceRepository.GetCustomerInvoicesByClientId(clientId);

            // Enrich each invoice with its approved paid total and outstanding balance,
            // preserving the nested shape the frontend reads.
            var result = new List<object>(invoices.Count);
            foreach (var invoice in invoices)
            {
                var paid = await _paymentRepository.GetApprovedPaidAmountAsync(invoice.CustomerInvoiceId);
                var link = invoice.CustomerSubscription?.TenantCustomerLink;
                result.Add(new
                {
                    invoice.CustomerInvoiceId,
                    invoice.FKCustomerSubscriptionId,
                    invoice.FKClientId,
                    invoice.Amount,
                    invoice.Status,
                    invoice.IsActive,
                    invoice.CustomerInvoiceDate,
                    PaidAmount = paid,
                    Balance = invoice.Amount - paid,
                    // Flattened for callers that don't want to reach through
                    // CustomerSubscription.TenantCustomerLink for basic display fields.
                    CustomerName = link?.DisplayName,
                    CustomerPhone = link?.PrimaryPhoneCached,
                    FKCustomerId = invoice.CustomerSubscription?.FKCustomerId,
                    invoice.CustomerSubscription
                });
            }
            return result;
        }

        public async Task<object> UpdateCustomerInvoiceStatus(object payload, HttpContext httpContext)
        {
            await _uow.BeginAsync();
            try
            {
                var data = DeserializePayload.Deserialize(payload);
                
                if (!data!.ContainsKey("customerInvoiceId") || !data.ContainsKey("status"))
                {
                    throw new KeyNotFoundException("customerInvoiceId and status are required");
                }

                var customerInvoiceId = Guid.Parse(data["customerInvoiceId"].GetString()!);
                var status = data["status"].GetString()!;
                
                // Validate status
                var validStatuses = new[] { "Pending", "Partial", "Paid", "Failed", "Cancelled", "Refunded", "RolledOver" };
                if (!validStatuses.Contains(status))
                {
                    throw new InvalidOperationException($"Invalid status. Valid statuses are: {string.Join(", ", validStatuses)}");
                }

                var result = await _customerInvoiceRepository.UpdateCustomerInvoiceStatus(customerInvoiceId, status);
                await _uow.CommitAsync();
                
                return result;
            }
            catch
            {
                await _uow.RollbackAsync();
                throw;
            }
        }


        public async Task<object> CalculateCustomerInvoiceTotal(object payload, HttpContext httpContext)
        {
            var data = DeserializePayload.Deserialize(payload);
            
            if (!data!.ContainsKey("customerInvoiceId"))
            {
                throw new KeyNotFoundException("customerInvoiceId is required");
            }

            var customerInvoiceId = Guid.Parse(data["customerInvoiceId"].GetString()!);
            var customerInvoice = await _customerInvoiceRepository.GetCustomerInvoiceById(customerInvoiceId);
            var total = customerInvoice?.Amount ?? 0;
            
            return new { Total = total };
        }
    }
}