using AutoMapper;
using Kean.Domain.Stock.Commands;
using Kean.Domain.Stock.Enums;
using Kean.Domain.Stock.Events;
using Kean.Domain.Stock.Repositories;
using Kean.Domain.Stock.Strategies;
using System;
using System.Threading;
using System.Threading.Tasks;

namespace Kean.Domain.Stock.CommandHandlers
{
    /// <summary>
    /// 重定位命令处理程序
    /// </summary>
    public sealed class RelocateCommandHandler : CommandHandler<RelocateCommand>
    {
        private readonly ICommandBus _commandBus; // 命令总线
        private readonly IMapper _mapper; // 模型映射
        private readonly IStockRepository _stockRepository; // 存储仓库
        private readonly IWarehouseRepository _warehouseRepository; // 库房仓库
        private readonly StateContext<StateStrategy_Default> _stateContext; // 库存状态判定策略

        /// <summary>
        /// 依赖注入
        /// </summary>
        public RelocateCommandHandler(
            IServiceProvider serviceProvider,
            IWarehouseRepository warehouseRepository,
            ICommandBus commandBus,
            IMapper mapper,
            IStockRepository stockRepository)
        {
            _commandBus = commandBus;
            _mapper = mapper;
            _stockRepository = stockRepository;
            _warehouseRepository = warehouseRepository;
            _stateContext = new(serviceProvider);
        }

        /// <summary>
        /// 处理程序
        /// </summary>
        public override async Task Handle(RelocateCommand command, CancellationToken cancellationToken)
        {
            var transfer = true;
            // 当前位置
            switch (await _warehouseRepository.IsCell(command.Original))
            {
                // 货位
                case true:
                    // 置空
                    await _warehouseRepository.UpdateCell(command.Original, CellState.Empty);
                    break;
            }
            var state = await _stateContext.GetState(command.Barcode);
            // 目标位置
            switch (await _warehouseRepository.IsCell(command.Destination))
            {
                // 货位
                case true:
                    // 空，认为是空托盘，创建库存
                    if (state == CellState.Empty)
                    {
                        transfer = false;
                        await _stockRepository.CreateStock(new()
                        {
                            Barcode = command.Barcode,
                            Cell = command.Destination,
                            Spec = command.Spec
                        });
                        await _warehouseRepository.UpdateCell(command.Destination, CellState.Pallet);
                    }
                    // 非空托盘，更新目标状态
                    else
                    {
                        await _stockRepository.CleanTag(command.Barcode);
                        await _warehouseRepository.UpdateCell(command.Destination, state);
                    }
                    break;
                // 站台
                case false:
                    // 空托盘，删除库存
                    if (state == CellState.Pallet)
                    {
                        //transfer = false;
                        //await _stockRepository.DeleteStock(new()
                        //{
                        //    Barcode = command.Barcode
                        //});
                    }
                    // 空，发生在站台到站台的空托盘移动，不做操作
                    else if (state == CellState.Empty)
                    {
                        transfer = false;
                    }
                    break;
            }
            if (transfer)
            {
                await _stockRepository.TransferStock(command.Barcode, command.Spec, command.Destination);
            }
            await _commandBus.Trigger(_mapper.Map<RelocateSuccessEvent>(command), cancellationToken);
        }
    }
}