using CMSMicroservice.Application.Common.Interfaces;
using CMSMicroservice.Domain.Enums;
using MediatR;
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.Logging;

namespace CMSMicroservice.Application.OrderManagementCQ.Commands.CancelOrderByAdmin;

public class CancelOrderByAdminCommandHandler : IRequestHandler<CancelOrderByAdminCommand, Unit>
{
    private readonly IApplicationDbContext _context;
    private readonly ICurrentUserService _currentUser;
    private readonly IInventoryService _inventoryService;
    private readonly ILogger<CancelOrderByAdminCommandHandler> _logger;

    public CancelOrderByAdminCommandHandler(
        IApplicationDbContext context,
        ICurrentUserService currentUser,
        IInventoryService inventoryService,
        ILogger<CancelOrderByAdminCommandHandler> logger)
    {
        _context = context;
        _currentUser = currentUser;
        _inventoryService = inventoryService;
        _logger = logger;
    }

    public async Task<Unit> Handle(CancelOrderByAdminCommand request, CancellationToken cancellationToken)
    {
        // بررسی Admin
        if (string.IsNullOrEmpty(_currentUser.UserId))
        {
            throw new UnauthorizedAccessException("کاربر احراز هویت نشده است");
        }

        var order = await _context.UserOrders
            .Include(x => x.User)
            .ThenInclude(x => x.UserWallets)
            .Include(x => x.FactorDetails)
            .FirstOrDefaultAsync(x => x.Id == request.OrderId && !x.IsDeleted, cancellationToken);

        if (order == null)
        {
            throw new KeyNotFoundException($"سفارش با شناسه {request.OrderId} یافت نشد");
        }

        if (order.DeliveryStatus == DeliveryStatus.Cancelled)
        {
            throw new InvalidOperationException("این سفارش قبلاً لغو شده است");
        }

        if (order.DeliveryStatus == DeliveryStatus.Delivered)
        {
            throw new InvalidOperationException("سفارش تحویل داده شده را نمی‌توان لغو کرد");
        }

        // تغییر وضعیت به لغو شده
        order.DeliveryStatus = DeliveryStatus.Cancelled;
        order.DeliveryDescription = $"لغو توسط Admin: {request.CancelReason}";

        // بازگشت وجه به کیف پول
        if (request.RefundToWallet && order.PaymentMethod == PaymentMethod.Wallet)
        {
            var wallet = order.User.UserWallets.FirstOrDefault();
            if (wallet != null)
            {
                var walletLog = new UserWalletHistory
                {
                    WalletId = wallet.Id,
                    CurrentBalance = wallet.Balance,
                    CurrentNetworkBalance = wallet.NetworkBalance,
                    CurrentDiscountBalance = wallet.DiscountBalance,
                    ChangeValue = order.Amount,
                    ChangeDiscountValue = 0,
                    IsIncrease = true,
                    RefrenceId = order.Id
                };

                wallet.Balance += order.Amount;
                
                await _context.UserWalletHistories.AddAsync(walletLog, cancellationToken);
                
                _logger.LogInformation(
                    "Refund processed. OrderId: {OrderId}, Amount: {Amount}, UserId: {UserId}",
                    order.Id,
                    order.Amount,
                    order.UserId
                );
            }
        }

        await _context.SaveChangesAsync(cancellationToken);

        // Restore inventory for each item (only if order was not yet delivered)
        if (order.FactorDetails != null && order.FactorDetails.Any())
        {
            foreach (var item in order.FactorDetails)
            {
                var restored = await _inventoryService.ProcessReturnAsync(
                    item.ProductId, ProductType.RegularProduct,
                    item.Count, order.Id,
                    note: $"برگشت موجودی — لغو سفارش #{order.Id} توسط Admin",
                    ct: cancellationToken);

                if (!restored)
                {
                    _logger.LogWarning(
                        "Failed to restore inventory for ProductId={ProductId} on cancel OrderId={OrderId}",
                        item.ProductId, order.Id);
                }
            }
        }

        _logger.LogInformation(
            "Order cancelled by admin. OrderId: {OrderId}, Reason: {Reason}, Refunded: {Refunded}, Admin: {AdminId}",
            order.Id,
            request.CancelReason,
            request.RefundToWallet,
            _currentUser.UserId
        );

        return Unit.Value;
    }
}