#pragma once

#include "GraphicsTags.hpp"
#include "RcPtr.hpp"
#include "SmallVector.hpp"

#include <glad/glad.h>
#include <cstddef>
#include <cstdint>
#include <vector>

struct GpuVertexBuffer : public RefCounted {
	GLuint handle;
	int sizeInBytes;

	GpuVertexBuffer();
	~GpuVertexBuffer();

	void Upload(const std::byte* data, size_t sizeInBytes);
};

struct GpuIndexBuffer : public RefCounted {
	GLuint handle;
	Tags::IndexType indexType;
	int count;

	GpuIndexBuffer();
	~GpuIndexBuffer();

	Tags::IndexType GetIndexType() const { return indexType; }
	GLenum GetIndexTypeGL() const { return Tags::FindGLType(indexType); }

	void Upload(const std::byte* data, Tags::IndexType type, size_t count);
};

struct BufferBindings {
	SmallVector<RcPtr<GpuVertexBuffer>, 4> bindings;

	int GetMaxBindingIndex() const;

	/// Safe. Returns nullptr if the index is not bound to any buffers.
	GpuVertexBuffer* GetBinding(int index) const;
	/// Adds or updates a buffer binding. Setting a binding to nullptr effectively removes the binding.
	void SetBinding(int index, GpuVertexBuffer* buffer);
	void Clear();
};

struct VertexElementFormat {
	/// NOTE:
	/// "Automatic" means it will be set inside VertexFormat::AddElement()
	/// "Parameter" means it must be set by the user
	/* Automatic */ int offset;
	/* Parameter */ int bindingIndex;
	/* Parameter */ Tags::VertexElementType type;
	/* Parameter */ Tags::VertexElementSemantic semantic;

	int GetStride() const;
};

struct VertexFormat : public RefCounted {
	SmallVector<VertexElementFormat, 4> elements;
	int vertexSize = 0;

	const decltype(elements)& GetElements() const { return elements; }
	void AddElement(VertexElementFormat element);
	void RemoveElement(int index);
};