using Serein.Library.Api;
using Serein.Library.Utils;
using System.Collections.Concurrent;

namespace Serein.Library.Core.NodeFlow
{

    /// <summary>
    /// 动态流程上下文
    /// </summary>
    public class DynamicContext: IDynamicContext
    {
        /// <summary>
        /// 动态流程上下文
        /// </summary>
        /// <param name="flowEnvironment"></param>
        public DynamicContext(IFlowEnvironment flowEnvironment)
        {
            Env = flowEnvironment;
            RunState = RunState.Running;
        }

        /// <summary>
        /// 运行环境
        /// </summary>
        public IFlowEnvironment Env { get; }

        /// <summary>
        /// 运行状态
        /// </summary>
        public RunState RunState { get; set; } = RunState.NoStart;

        /// <summary>
        /// 当前节点执行完成后，设置该属性，让运行环境判断接下来要执行哪个分支的节点。
        /// </summary>
        public ConnectionInvokeType NextOrientation { get; set; }

        /// <summary>
        /// 每个流程上下文分别存放节点的当前数据
        /// </summary>
        private readonly ConcurrentDictionary<string, object?> dictNodeFlowData = new ConcurrentDictionary<string, object?>();

        /// <summary>
        /// 每个流程上下文存储运行时节点的调用关系
        /// </summary>
        private readonly ConcurrentDictionary<NodeModelBase, NodeModelBase> dictPreviousNodes = new ConcurrentDictionary<NodeModelBase, NodeModelBase>();

        /// <summary>
        /// 设置运行时上一节点
        /// </summary>
        /// <param name="currentNodeModel">当前节点</param>
        /// <param name="PreviousNode">上一节点</param>
        public void SetPreviousNode(NodeModelBase currentNodeModel, NodeModelBase PreviousNode)
        {
            dictPreviousNodes.AddOrUpdate(currentNodeModel, (_)=> PreviousNode, (_,_) => PreviousNode);
        }

        /// <summary>
        /// 获取当前节点的运行时上一节点
        /// </summary>
        /// <param name="currentNodeModel"></param>
        /// <returns></returns>
        public NodeModelBase GetPreviousNode(NodeModelBase currentNodeModel)
        {
            if (dictPreviousNodes.TryGetValue(currentNodeModel, out var node))
            {
                return node;
            }
            else
            {
                return null;
            }
        }


        /// <summary>
        /// 获取节点当前数据
        /// </summary>
        /// <param name="nodeGuid">节点</param>
        /// <returns></returns>
        public object? GetFlowData(string nodeGuid)
        {
            if(dictNodeFlowData.TryGetValue(nodeGuid, out var data))
            {
                return data;
            }
            else
            {
                return null;
            }
        }

        /// <summary>
        /// 添加或更新当前节点数据
        /// </summary>
        /// <param name="nodeGuid">节点</param>
        /// <param name="flowData">新的数据</param>
        public void AddOrUpdate(string nodeGuid, object? flowData)
        {
            // this.dictNodeFlowData.TryGetValue(nodeGuid, out var oldFlowData);
            this.dictNodeFlowData.AddOrUpdate(nodeGuid, _ => flowData, (_, _) => flowData);
        }

        /// <summary>
        /// 上一节点数据透传到下一节点
        /// </summary>
        /// <param name="nodeModel"></param>
        public object? TransmissionData(NodeModelBase nodeModel)
        {
            if (dictPreviousNodes.TryGetValue(nodeModel, out var previousNode)) // 首先获取当前节点的上一节点
            { 
               if (dictNodeFlowData.TryGetValue(previousNode.Guid, out var data)) // 其次获取上一节点的数据
               {
                    return data;
                    //AddOrUpdate(nodeModel.Guid, data); // 然后作为当前节点的数据记录在上下文中
               }
            }
            return null;
        }


        /// <summary>
        /// 结束流程
        /// </summary>
        public void Exit()
        {
            foreach (var nodeObj in dictNodeFlowData.Values)
            {
                if (nodeObj is not null)
                {
                    if (typeof(IDisposable).IsAssignableFrom(nodeObj?.GetType()) && nodeObj is IDisposable disposable)
                    {
                        disposable?.Dispose();
                    }
                }
            }
            this.dictNodeFlowData?.Clear();
            RunState = RunState.Completion;
        }

    }
}