//-----------------------------------------------------------------------
//-----------------------------------------------------------------------
//     file="ViewResponder.cs"
//     Project: StgSharp
//     AuthorGroup: Nitload Space
//     Copyright (c) Nitload Space. All rights reserved.
//     
//     Permission is hereby granted, free of charge, to any person 
//     obtaining a copy of this software and associated documentation 
//     files (the “Software”), to deal in the Software without restriction, 
//     including without limitation the rights to use, copy, modify, merge,
//     publish, distribute, sublicense, and/or sell copies of the Software, 
//     and to permit persons to whom the Software is furnished to do so, 
//     subject to the following conditions:
//     
//     The above copyright notice and 
//     this permission notice shall be included in all copies 
//     or substantial portions of the Software.
//     
//     THE SOFTWARE IS PROVIDED “AS IS”, 
//     WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, 
//     INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 
//     FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. 
//     IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, 
//     DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, 
//     ARISING FROM, OUT OF OR IN CONNECTION WITH 
//     THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//     
//-----------------------------------------------------------------------
//-----------------------------------------------------------------------
using StgSharp.Controlling.UsrActivity;
using StgSharp.MVVM.ViewModel;

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

namespace StgSharp.MVVM.View
{
    public partial class ViewBase
    {

        protected interface IViewResponder<out TVIew> where TVIew: ViewBase
        {

            Action? this[ IClickTrigger trigger ]
            {
                get;
                set;
            }

            void CustomizedInitialize(
                Func<IClickTrigger, string, Action> keyRegister );

            void Initialize( MethodLookUpDelegate methodGetter );

            void ProcessUserInput();

            bool ValidateInitializing();

        }

        protected abstract class ViewResponder<TView> : IViewResponder<TView>
            where TView: ViewBase
        {

            private bool _isInitialized;
            private Dictionary<IClickTrigger, Action> keyCallbackIndex;
            private Dictionary<string, Action> nameToCallbackMap;
            private TView _binding;

            protected ViewResponder( TView binding )
            {
                keyCallbackIndex = new Dictionary<IClickTrigger, Action>();
                nameToCallbackMap = new Dictionary<string, Action>();
                _binding = binding;
            }

            #pragma warning disable CA1043
            public Action? this[ IClickTrigger trigger ]
            #pragma warning restore CA1043
            {
                get => keyCallbackIndex.TryGetValue(
                    trigger, out Action callback ) ?
                callback : null;
                set
                {
                    if( keyCallbackIndex.TryGetValue(
                        trigger, out Action callback ) ) {
                        callback += value;
                    } else {
                        keyCallbackIndex.Add(
                            trigger,
                            value ??
                                throw new ArgumentNullException(
                                    nameof( value ) ) );
                    }
                }
            }

            protected TView Binding => _binding;

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

            public void Initialize( MethodLookUpDelegate methodGetter )
            {
                if( _isInitialized ) {
                    return;
                }
                CustomizedInitialize(
                    ( trigger, name ) => {
                        if( !nameToCallbackMap.TryGetValue(
                            name, out Action ret ) ) {
                            if( methodGetter( name, out Action lookup ) ) {
                                this[ trigger ] = lookup;
                            } else {
                                throw new InvalidOperationException(
                                    $"Cannot find method named {name} in binded view model" );
                            }
                        }
                        return ret;
                    } );
            }

            public void ProcessUserInput()
            {
                foreach( KeyValuePair<IClickTrigger, Action> pair in keyCallbackIndex ) {
                    if( InternalIO.glfwGetKey(
                        _binding.ViewHandle,
                        pair.Key.TargetKeyOrButtonID ) == pair.Key.TriggeredStatus ) {
                        pair.Value();
                    }
                }
            }

            public abstract bool ValidateInitializing();

        }

    }
}