using System.Collections.Generic;
using Microsoft.Xna.Framework.Graphics;

namespace Kav
{
    public static class Renderer
    {
        public static void Render(GraphicsDevice graphicsDevice, Camera camera, IEnumerable<Model> models, IEnumerable<PointLight> pointLights)
        {
            var view = camera.View;
            var projection = camera.Projection;

            foreach (var model in models)
            {
                foreach (var modelMesh in model.Meshes)
                {
                    foreach (var meshPart in modelMesh.MeshParts)
                    {
                        graphicsDevice.SetVertexBuffer(meshPart.VertexBuffer);
                        graphicsDevice.Indices = meshPart.IndexBuffer;

                        if (meshPart.Effect is TransformEffect transformEffect)
                        {
                            transformEffect.View = view;
                            transformEffect.Projection = projection;
                        }

                        if (meshPart.Effect is PointLightEffect pointLightEffect)
                        {
                            int i = 0;
                            foreach (var pointLight in pointLights)
                            {
                                if (i > pointLightEffect.MaxPointLights) { break; }
                                pointLightEffect.PointLights[i] = pointLight;
                                i++;
                            }
                        }

                        foreach (var pass in meshPart.Effect.CurrentTechnique.Passes)
                        {
                            pass.Apply();

                            graphicsDevice.DrawIndexedPrimitives(
                                PrimitiveType.TriangleList,
                                0,
                                0,
                                meshPart.VertexBuffer.VertexCount,
                                0,
                                meshPart.Triangles.Length
                            );
                        }
                    }
                }
            }
        }
    }
}