using System;
using System.Collections.Generic;
using OpenTK.Windowing.Desktop;
using OpenTK.Windowing.GraphicsLibraryFramework;
using Dashboard.CommandMachine;
using Dashboard.Media;
using Dashboard.OpenGL;
using Dashboard.PAL;

namespace Dashboard.OpenTK
{
    public class OpenTKPlatform : IDashboardPlatform
    {
        private readonly List<OpenTKPort> _ports = new List<OpenTKPort>();

        // These shall remain a sad nop for now.
        public string? Title { get; set; }
        public QImage? Icon { get; set; } = null;

        public event EventHandler? EventRaised;

        public NativeWindowSettings DefaultSettings { get; set; } = NativeWindowSettings.Default;

        public IReadOnlyList<OpenTKPort> Ports => _ports;

        private bool IsGLInitialized = false;

        public IDashHandle CreatePort()
        {
            NativeWindow window = new NativeWindow(DefaultSettings);
            OpenTKPort port = new OpenTKPort(window);
            _ports.Add(port);

            if (!IsGLInitialized)
            {
                window.Context.MakeCurrent();
                GL.LoadBindings(GLFW.GetProcAddress);
                IsGLInitialized = true;
            }

            window.Closing += (ea) =>
            {
                Environment.Exit(0);
            };

            return port;
        }

        public void Dispose()
        {
            // FIXME: dispose pattern here!

            // Copy the array to prevent collection modification exceptions.
            foreach (OpenTKPort port in _ports.ToArray())
            {
                port.Dispose();
            }
        }

        public void ProcessEvents(bool block)
        {
            NativeWindow.ProcessWindowEvents(block);
        }

        public void DestroyPort(IDashHandle port) => ((OpenTKPort)port).Dispose();

        public string PortGetTitle(IDashHandle port) => ((OpenTKPort)port).Title;

        public void PortSetTitle(IDashHandle port, string title) => ((OpenTKPort)port).Title = title;

        public QVec2 PortGetSize(IDashHandle port) => ((OpenTKPort)port).Size;

        public void PortSetSize(IDashHandle port, QVec2 size) => ((OpenTKPort)port).Size = size;

        public QVec2 PortGetPosition(IDashHandle port) => ((OpenTKPort)port).Position;

        public void PortSetPosition(IDashHandle port, QVec2 position) => ((OpenTKPort)port).Position = position;

        public bool PortIsValid(IDashHandle port) => ((OpenTKPort)port).IsValid;

        public void PortSubscribeEvent(IDashHandle port, EventHandler handler) => ((OpenTKPort)port).EventRaised += handler;

        public void PortUnsubscribeEvent(IDashHandle port, EventHandler handler) => ((OpenTKPort)port).EventRaised -= handler;

        public void PortFocus(IDashHandle port) => ((OpenTKPort)port).Focus();

        public void PortShow(IDashHandle port, bool shown = true) => ((OpenTKPort)port).Show(shown);

        public void PortPaint(IDashHandle port, CommandList commands) => ((OpenTKPort)port).Paint(commands);

        public void GetMaximumImage(out int width, out int height)
        {
            GL.Get(GLEnum.GL_MAX_TEXTURE_SIZE, out int value);
            width = height = value;
        }

        public void GetMaximumImage(out int width, out int height, out int depth)
        {
            GetMaximumImage(out width, out height);
            GL.Get(GLEnum.GL_MAX_ARRAY_TEXTURE_LAYERS, out int value);
            depth = value;
        }
    }
}