using StgSharp.Controlling.UsrActivity;
using StgSharp.Graphics;

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

namespace StgSharp
{
    public abstract class ViewResponder<TView> where TView: View
    {
        private View _viewbinding;
        private Dictionary<ITrigger, Action> keyCallbackIndex;
        private Dictionary<string, Action> nameToCallbackMap;
        private bool _isInitialized;


        protected ViewResponder()
        {
            keyCallbackIndex = new Dictionary<ITrigger, Action>();
            nameToCallbackMap = new Dictionary<string, Action>();
        }

        internal void ProcessUserInput()
        {
            foreach (var pair in keyCallbackIndex)
            {
                ITrigger t = pair.Key;
                if (InternalIO.glfwGetKey(_viewbinding.ViewHandle, t.TargetKeyOrButtonID) == t.TriggeredStatus)
                {
                    pair.Value();
                }
            }
        }

        public Action this[ITrigger trigger]
        {
            get => keyCallbackIndex.TryGetValue(trigger, out Action callback) ? callback : null;
            set
            {
                if (keyCallbackIndex.TryGetValue(trigger, out Action callback))
                {
                    callback += value;
                }
                else
                {
                    keyCallbackIndex.Add(trigger, value);
                }
            }
        }

        internal void Init(Func<string, Action> keyGetter)
        {
            if (_isInitialized)
            {
                return;
            }
            CustomizedInitialize(
                (trigger, name) =>
                {
                    if (!nameToCallbackMap.TryGetValue(name, out Action ret))
                    {
                        ret = keyGetter.Invoke(name)??
                            throw new InvalidOperationException($"Cannot find method named {name} in binded view model");
                    }
                    this[trigger] = ret;
                    return ret;
                }
                );
        }

        public void ProcessInput()
        {
            foreach (var pair in keyCallbackIndex)
            {
                if (InternalIO.glfwGetKey(_viewbinding.ViewHandle,(int)pair.Key.TargetKeyOrButtonID) == pair.Key.TriggeredStatus)
                {
                    pair.Value();
                }
            }
        }

        public abstract void CustomizedInitialize(Func<ITrigger, string, Action> keyRegister);

        public abstract bool ValidateInitializing();

    }


}