//-----------------------------------------------------------------------
//-----------------------------------------------------------------------
//     file="glRenderStream.cs"
//     Project: StepVisualizer
//     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.Math;
using StgSharp.Threading;

using System;
using System.Collections.Concurrent;
using System.Collections.Generic;
using System.Linq;
using System.Reflection;
using System.Runtime.CompilerServices;
using System.Runtime.InteropServices;
using System.Text;
using System.Threading;
using System.Threading.Tasks;

namespace StgSharp.Graphics.OpenGL
{
    public abstract partial class glRender : RenderStream
    {

        private protected static readonly ConcurrentDictionary<glRender, Thread> renderToThread
            = new ConcurrentDictionary<glRender, Thread>();

        private OpenGLFunction _context;

        protected internal OpenGLFunction GL
        {
            get { return _context; }
        }

        /// <summary>
        ///   Initialize an opengl context and load all opengl functions.
        /// </summary>
        public unsafe void InitializeContext()
        {
            if( ContextHandle == default )
            {
                ContextHandle = Marshal.AllocHGlobal( Marshal.SizeOf( typeof( OpenglContext ) ) );
                OpenglContext* contextID = ( OpenglContext* )ContextHandle;
                contextID->glGetString = ( delegate*<uint, IntPtr> )IntPtr.Zero;
            }
            if( GL == null ) {
                _context = OpenGLFunction.BuildGlFunctionPackage( ContextHandle );
            }
        }

        /// <summary>
        ///   Initialize an OpenGl viewPortDisplay if current form has not been binded to any
        ///   viewPortDisplay.  and set the viewPortDisplay binded to current form as current OpenGL
        ///   viewPortDisplay.
        /// </summary>
        /// <exception cref="Exception">
        ///   Something goes wrong and World fails in creating a new OpenGL viewPortDisplay.
        /// </exception>
        public unsafe void MakeAsCurrentContext()
        {
            InternalIO.glfwMakeContextCurrent( CanvasHandle );
            OpenGLFunction.CurrentGL = this.GL;
        }

        /// <inheritdoc />
        public override void RenderEnd()
        {
            if( !renderToThread.TryGetValue( this, out Thread t ) || t != Thread.CurrentThread ) {
                throw new InvalidOperationException(
                    $"Current render has had been binded to thread {t!.ManagedThreadId}" );
            }
            SwapBuffers();
            renderToThread[ this ] = ThreadHelper.EmptyThread;
            InternalIO.glfwMakeContextCurrent( IntPtr.Zero );
            OpenGLFunction.CurrentGL = null;
        }

        /// <inheritdoc />
        public override void RenderStart()
        {
            Thread current = Thread.CurrentThread;
            if( !renderToThread.TryGetValue( this, out Thread t ) || t == ThreadHelper.EmptyThread )
            {
                renderToThread[ this ] = current;
                MakeAsCurrentContext();
                return;
            }
            if( t != current ) {
                throw new InvalidOperationException(
                    $"Current render has had been binded to thread {t!.ManagedThreadId}" );
            }
        }

        [MethodImpl( MethodImplOptions.AggressiveInlining )]
        public override void SetSizeLimit(
                             int minWidth,
                             int minHeight,
                             int maxWidth,
                             int maxHeight )
        {
            InternalIO.glfwSetWindowSizeLimits(
                this.CanvasHandle, minWidth, minHeight, maxWidth, maxHeight );
        }

        [MethodImpl( MethodImplOptions.AggressiveInlining )]
        internal override sealed void PlatformSpecifiedInitialize()
        {
            InitializeContext();
            MakeAsCurrentContext();
            glManager.LoadOpenGLApiTo( BindedViewPortContext.GraphicHandle );
        }

        [MethodImpl( MethodImplOptions.AggressiveInlining )]
        internal override sealed void Terminate()
        {
            CustomizeDeinit();
        }

        protected override sealed Uniform<Matrix44> NativeCameraUniform(
                                                    ShaderProgram source,
                                                    string name )
        {
            NativeCamera.GainAllUniforms( source, name );
            return NativeCamera.convertedUniform;
        }

        [MethodImpl( MethodImplOptions.AggressiveInlining )]
        protected override sealed void NativeCameraViewRange(
                                       Radius fieldOfRange,
                                       Vec2 offset,
                                       (float frontDepth, float backDepth) viewDepth )
        {
            NativeCamera.SetViewRange( fieldOfRange, this.Size, offset, viewDepth );
        }

        [MethodImpl( MethodImplOptions.AggressiveInlining )]
        protected override sealed void NativeCameraViewTarget(
                                       Vec3 position,
                                       Vec3 direction,
                                       Vec3 up )
        {
            NativeCamera.SetViewDirection( position, direction, up );
        }

        #region Key Control

        protected KeyStatus CheckKey( KeyboardKey key )
        {
            return InternalIO.glfwGetKey( this.CanvasHandle, ( int )key );
        }

        protected KeyStatus CheckKey( Mouse key )
        {
            return InternalIO.glfwGetKey( this.CanvasHandle, ( int )key );
        }

        protected KeyStatus CheckKey( Joystick key )
        {
            return InternalIO.glfwGetKey( this.CanvasHandle, ( int )key );
        }

        #endregion
    }
}