//-----------------------------------------------------------------------
//-----------------------------------------------------------------------
//     file="RenderStream.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.Graphics.OpenGL;
using StgSharp.Math;

using StgSharp.MVVM;
using StgSharp.Timing;

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Diagnostics.CodeAnalysis;
using System.Linq;
using System.Runtime.CompilerServices;
using System.Runtime.InteropServices;
using System.Text;
using System.Threading.Tasks;

namespace StgSharp.Graphics
{
    public abstract class RenderStream
    {

        private Camera nativeCamera;

        private protected ViewPort primeArgs;
        internal TimeSpanProvider _timeProvider;

        public (int width, int height) Size
        {
            get => (Width, Height);
        }

        public abstract bool IsContextSharable { get; }

        public int Height
        {
            get => primeArgs.Height;
        }

        public int Width
        {
            get => primeArgs.Width;
        }

        public IntPtr Monitor
        {
            get => primeArgs.Monitor;
            internal set => primeArgs.Monitor = value;
        }

        public string Name
        {
            get => primeArgs.Name;
        }

        public ViewPort BindedViewPortContext
        {
            get => primeArgs;
            internal set => primeArgs = value;
        }

        internal IntPtr CanvasHandle
        {
            get => primeArgs.ViewPortHandle;
        }

        internal IntPtr ContextHandle
        {
            get => primeArgs.GraphicHandle;
            private protected set => primeArgs.GraphicHandle = value;
        }

        protected internal Camera NativeCamera
        {
            get => nativeCamera;
            internal set => nativeCamera = value;
        }

        protected float FramePassed
        {
            get => _timeProvider.CurrentSpan;
        }

        protected int PassedFrames
        {
            get => _timeProvider.CurrentSpan;
        }

        protected float TimePassed
        {
            get => _timeProvider.CurrentSecond;
        }

        protected TimeSpanProvider TimeProvider
        {
            get => _timeProvider;
        }

        /// <summary>
        ///   Set the size limit of current form
        /// </summary>
        /// <param _label="minWidth">
        ///   Minimum width of current form
        /// </param>
        /// <param _label="minHeight">
        ///   Minimum height of current form
        /// </param>
        /// <param _label="maxWidth">
        ///   Maximum width of current form
        /// </param>
        /// <param _label="maxHeight">
        ///   Maximum height of current form
        /// </param>
        [MethodImpl( MethodImplOptions.AggressiveInlining )]
        public abstract void SetSizeLimit(
                             int minWidth,
                             int minHeight,
                             int maxWidth,
                             int maxHeight );

        public static TTarget ShareContextFrom<TSource, TTarget>( [NotNull]TSource source )
            where TSource: RenderStream
            where TTarget: RenderStream, new()
        {
            TTarget target = new TTarget();
            target.Initialize( source.BindedViewPortContext, source._timeProvider );
            return target;
        }

        /**/
        protected internal static void PollEvents()
        {
            InternalIO.glfwPollEvents();
        }

        private protected void SwapBuffers()
        {
            InternalIO.glfwSwapBuffers( CanvasHandle );
        }

        /**/

        #region native camera operation

        protected abstract void NativeCameraViewRange(
                                Radius fieldOfRange,
                                Vec2 offset,
                                (float frontDepth, float backDepth) viewDepth );

        protected abstract void NativeCameraViewTarget( Vec3 position, Vec3 direction, Vec3 up );

        /// <summary>
        ///   Get <see cref="Uniform{T}" />(TView is <see cref="Matrix44" />) uniform from a shader.
        ///   This uniform will be used as projection matrix of this camera. Additionally, for
        ///   multi- shader rendering, each shader requires a uniform,  so do not ignore return
        ///   value of this method.
        /// </summary>
        /// <param _label="source">
        ///   Shader using this camera
        /// </param>
        /// <param _label="name">
        ///   ContextName of projection camera named in shader
        /// </param>
        /// <returns>
        ///   <see cref="Uniform{T}" />(TView is <see cref="Matrix44" />) representing  projection
        ///   matrix in shader program.
        /// </returns>
        protected abstract Uniform<Matrix44> NativeCameraUniform(
                                             ShaderProgram source,
                                             string name );

        #endregion

        #region internal operation

        public void Initialize( ViewPort v, TimeSpanProvider timeProvider )
        {
            if( v == null ) {
                throw new ArgumentNullException( nameof( v ) );
            }
            primeArgs = v;
            this._timeProvider = timeProvider;
            nativeCamera = new Camera();
            PlatformSpecifiedInitialize();
            CustomizeInit();
            InternalIO.glfwMakeContextCurrent( IntPtr.Zero );
        }

        internal abstract void PlatformSpecifiedInitialize();

        internal abstract void Terminate();

        #endregion

        #region public operation

        protected abstract void CustomizeDeinit();

        protected abstract void CustomizeInit();

        /// <summary>
        ///   Marking the start of current render operations,  and set this renser context as
        ///   current.
        /// </summary>
        public abstract void RenderStart();

        /// <summary>
        ///   Marking the end of current render operations,  and release the binding of this renser
        ///   context to current,  making it available for another thread as current.
        /// </summary>
        public abstract void RenderEnd();

        #endregion

        #region public resource generator

        protected abstract Shader CreateShaderSegment( ShaderType type, int count );

        protected abstract ShaderProgram CreateShaderProgram();

    #endregion
    }
}