using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Threading;
using System.Threading;

using OpenSEMI.Core.Msg;

namespace OpenSEMI.ClientBase.Handlers
{
    public class StatesHandler : IHandler
    {
        public StatesHandler(Func<List<string>, List<State>> funcGetStates,List<string> allkeys)
        {
            this.Keys = new List<string>();
            this.CommonKeys = new List<string>();
            this.States = new Dictionary<string, State>();
            this.looper = new MsgPool(500, Do);

            //define an external function to let client implement 
            this.GetStates = funcGetStates;

            //init states list
            allkeys.ForEach(key => { this.States.Add(key, new State() { Key = key, DisplayValue = string.Empty }); });
        }

        public void Handle()
        {
            this.looper.Run();
        }

        public void Do(MsgPool pool)
        {
            List<string> summarykeys = new List<string>();

            lock (lockObj)
            {
                if (this.CommonKeys.Count == 0 && this.Keys.Count == 0)
                    return;

                if (Application.Current == null || Application.Current.Dispatcher == null)
                    return;
                //common and current page keys 
                
                if (this.CommonKeys.Count > 0)
                    summarykeys.AddRange(this.CommonKeys);
                if (this.Keys.Count > 0)
                    summarykeys.AddRange(this.Keys);
            }

            List<State> states = GetStates(summarykeys);
                Application.Current.Dispatcher.BeginInvoke(DispatcherPriority.Normal, (ThreadStart)delegate
                {
                    if (states == null) return;
                    states.ForEach(
                            state =>
                            {
                                if (this.States.ContainsKey(state.Key))
                                {
                                    this.States[state.Key].DisplayValue = state.DisplayValue;
                                }
                            }
                        );
                });

        }

        /// <summary>
        /// Register keys for each page or common page
        /// </summary>
        /// <param name="keys"></param>
        /// <param name="isCommon"></param>
        public void Register(List<string> keys, bool isCommon = false)
        {
            lock (lockObj)
            {         
                if (isCommon)
                {
                    keys.ForEach(e =>
                        {
                            if (!this.CommonKeys.Contains(e))
                                this.CommonKeys.Add(e);
                        });
                }
                else
                {
                    this.Keys.Clear();
                    this.Keys.AddRange(keys);
                }
            }
        }

        /// <summary>
        ///remove a page's key
        /// </summary>
        /// <param name="keys"></param>
        public void UnRegister(List<string> keys)
        {
            lock(lockObj)
            {
                this.Keys.Clear();
            }
        }

        public Dictionary<string, State> States { get; private set; }

        public MsgPool looper { get; private set; }
        private List<string> Keys { get; set; }
        private List<string> CommonKeys { get; set; }
        private Func<List<string>, List<State>> GetStates;
        private static object lockObj = new object();
    }
}