//-----------------------------------------------------------------------
//-----------------------------------------------------------------------
//     file="ShowViewPort.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.Graphics;
using StgSharp.MVVM.View;

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

namespace StgSharp.MVVM.ViewModel
{
    public abstract partial class ViewModelBase
    {

        private ViewBase _nextView, _currentView;

        protected ViewBase CurrentView
        {
            get => _currentView;
            set => _nextView = value;
        }

        /// <summary>
        /// CustomizeInit this form and render it on screen, and respond with operation
        /// </summary>
        public unsafe void UseViewModel(string viewEntryName)
        {
            CustomizeInitialize();
            //BuildGlobalKeyControl();
            UseViewInNextFrame(viewEntryName);
            while (0 == InternalIO.glfwWindowShouldClose(this.viewPortDisplay.ViewPortID))
            {
                ShowFrameOnce();
            }
        }

        private void ShowFrameOnce()
        {
            viewPortDisplay.FlushSize();
            if (_nextView != _currentView)
            {
                Interlocked.Exchange(ref _currentView, _nextView);
            }
            CurrentView.Use();
            RenderStream.PollEvents();
            frameTimeProvider.WaitNextSpan();
            Interlocked.Add(ref _frameCount, 1);
        }

        protected void UseViewInNextFrame(string name)
        {
            if (!allView.TryGetValue(name, out ViewBase v))
            {
                throw new KeyNotFoundException($"{($"Cannot find View named {name} ")}{($"in current View Model of {GetType().FullName}")}");
            }
            CurrentView = v;
        }

        private unsafe void PrivateShow()
        {
            if (0 == InternalIO.glfwWindowShouldClose(this.viewPortDisplay.ViewPortID))
            {
                CurrentView.Use();
                RenderStream.PollEvents();
            }
        }

    }
}