using System.Data;
using System.Drawing;
using System.Numerics;
using System.Runtime.InteropServices;
using Dashboard.Layout;
using Dashboard.Pal;

namespace Dashboard.Drawing
{
    public record struct RectangleDrawInfo(Vector2 Position, ComputedBox Box, Brush Fill, Brush? Border = null);

    [StructLayout(LayoutKind.Explicit, Size = Size)]
    public struct ImmediateVertex()
    {
        [field: FieldOffset(PosOffset)]
        public Vector3 Position { get; init; }= Vector3.Zero;
        
        [field: FieldOffset(TexCoordsOffset)]
        public Vector2 TexCoords { get; init; } = Vector2.Zero;
        
        [field: FieldOffset(ColorOffset)]
        public Vector4 Color { get; init; } = Vector4.One;

        public ImmediateVertex(Vector3 position, Vector2 texCoords, Vector4 color) : this()
        {
            Position = position;
            TexCoords = texCoords;
            Color = color;
        }

        public ImmediateVertex(Vector3 position, Vector2 texCoords, Color color) 
            : this(
                position,
                texCoords,
                new Vector4(color.R / 255f, color.G / 255f, color.B / 255f, color.A / 255f))
        {
        }

        public const int Size = 16 * sizeof(float);
        public const int PosOffset = 0 * sizeof(float);
        public const int TexCoordsOffset = 4 * sizeof(float);
        public const int ColorOffset = 8 * sizeof(float);
    }

    public struct ImmediateDrawCall(MeshPrimitive primitive, ReadOnlyMemory<ImmediateVertex> vertices)
    {
        public MeshPrimitive Primitive { get; init; } = primitive;
        public ReadOnlyMemory<ImmediateVertex> Vertices { get; init; } = vertices;
        public PipelineState PipelineState { get; init; } = new PipelineState();
        public Matrix4x4 Transforms { get; init; } = Matrix4x4.Identity;
        public ITexture? Texture { get; init; } = null;
    }

    public interface IImmediateMode : IDeviceContextExtension
    {
        /// <summary>
        /// Enqueue a draw with the immediate mode shader pipeline.
        /// </summary>
        /// <param name="call">Information about this draw call.</param>
        void DrawImmediate(ImmediateDrawCall call);

        // TODO: move these to their own extension?
        void Line(Vector2 a, Vector2 b, float width, float depth, Vector4 color);
        void Rectangle(Box2d rectangle, float depth, Vector4 color);
        void Rectangle(in RectangleDrawInfo rectangle);
        void Image(Box2d rectangle, Box2d uv, float depth, ITexture texture);
    }
}