using Kean.Domain.Stock.Enums;
using System;
using System.Linq;
using System.Threading.Tasks;

namespace Kean.Domain.Stock.Strategies
{
    /// <summary>
    /// 库存状态判定策略上下文
    /// </summary>
    public sealed class StateContext<T> where T : StateStrategy
    {
        private readonly T _strategy; // 策略实例

        /// <summary>
        /// 初始化 Kean.Domain.Stock.Strategies.StateContext 类的新实例
        /// </summary>
        public StateContext(IServiceProvider serviceProvider) =>
            _strategy = Activator.CreateInstance(typeof(T),
                typeof(T).GetConstructors().First().GetParameters().Select(p => serviceProvider.GetService(p.ParameterType)).ToArray()) as T;


        /// <summary>
        /// 判定库存状态
        /// </summary>
        /// <param name="barcode">托盘条码</param>
        /// <returns>库存状态</returns>
        public Task<CellState> GetState(string barcode) =>
            _strategy.GetState(barcode);
    }
}