using AutoMapper;
using Kean.Domain.Order.Commands;
using Kean.Domain.Order.Events;
using Kean.Domain.Order.Models;
using Kean.Domain.Order.Repositories;
using System.Threading;
using System.Threading.Tasks;

namespace Kean.Domain.Order.CommandHandlers
{
    /// <summary>
    /// 修改工作流命令处理程序
    /// </summary>
    public sealed class ModifyFlowCommandHandler : CommandHandler<ModifyFlowCommand>
    {
        private readonly ICommandBus _commandBus; // 命令总线
        private readonly IMapper _mapper; // 模型映射
        private readonly IOrderRepository _orderRepository; // 订单仓库

        /// <summary>
        /// 依赖注入
        /// </summary>
        public ModifyFlowCommandHandler(
            ICommandBus commandBus,
            IMapper mapper,
            IOrderRepository orderRepository)
        {
            _commandBus = commandBus;
            _mapper = mapper;
            _orderRepository = orderRepository;
        }

        /// <summary>
        /// 处理程序
        /// </summary>
        public override async Task Handle(ModifyFlowCommand command, CancellationToken cancellationToken)
        {
            if (command.ValidationResult.IsValid)
            {
                if (!await _orderRepository.IsFlowExist(command.Id))
                {
                    await _commandBus.Notify(nameof(command.Id), "工作流不存在", command.Id, nameof(ErrorCode.Gone),
                        cancellationToken: cancellationToken);
                    return;
                }
                if (await _orderRepository.IsFlowNameExist(command.Name, command.Id))
                {
                    await _commandBus.Notify(nameof(command.Name), "工作流描述已存在", command.Name, nameof(ErrorCode.Conflict),
                        cancellationToken: cancellationToken);
                    return;
                }
                if (command.Nodes != null || command.Paths != null)
                {
                    if (await _orderRepository.IsFlowUsing(command.Id))
                    {
                        await _commandBus.Notify(nameof(command.Id), "存在未完成实例", command.Id, nameof(ErrorCode.Locked),
                            cancellationToken: cancellationToken);
                        return;
                    }
                }
                await _orderRepository.ModifyFlow(_mapper.Map<Flow>(command));
                await _commandBus.Trigger(_mapper.Map<ModifyFlowSuccessEvent>(command), cancellationToken);
            }
            else
            {
                await _commandBus.Notify(command.ValidationResult,
                    cancellationToken: cancellationToken);
            }
        }
    }
}