#pragma once

#include <unordered_map>
#include <bit>
#include <format>
#include <ranges>
#include <bits/ranges_algo.h>

#include "assets/dynamic_data_stores/dynamic_shader_source_store.hpp"
#include "opengl/shader_program_lookup.hpp"
#include "opengl/handles/shader_handle.hpp"
#include "util/string_lookup.hpp"
#include "shader_preprocessor.hpp"
#include "opengl/metadata/shader_metadata.hpp"
#include "opengl/data/shader_data.hpp"
#include "opengl/handles/shader_handle_set.hpp"
#include "opengl/shading/requirements/shader_requirements.hpp"
#include "opengl/metadata/shader_set_metadata.hpp"
#include "opengl/shading/requirements/shader_set_requirements.hpp"

namespace zgl
{
class shader_program_compiler
{
	using shader_lookup_entry_type = std::pair<shader_metadata, shader_data>;

	static constexpr auto gl_shader_types = std::array<GLenum, shading::stage::count>{
		GL_VERTEX_SHADER,
		GL_TESS_CONTROL_SHADER,
		GL_TESS_EVALUATION_SHADER,
		GL_GEOMETRY_SHADER,
		GL_FRAGMENT_SHADER
	};


public:

	void preprocess(
		const dynamic_shader_source_store& shader_sources
	);

	void compile_shaders(
		const dynamic_shader_source_store& shader_sources,
		std::span<const shading::shader_set_requirements> requirements,
		std::span<shader_set_metadata> metadata,
		std::span<shader_handle_set> shader_sets
	);

protected:
	shader_handle find_shader(
		const shading::shader_requirements& requirements
	);

	bool compile_shader(
		GLenum shader_type,
		std::span<const char*> source_strings,
		shader_data& shader
	);

private:
	shader_preprocessor m_preprocessor{};

	std::vector<shading::shader_source_requirements> m_source_requirement_buffer{};
	std::vector<preprocessed_shader_source_metadata> m_preprocessed_shader_source_metadata_buffer;
	std::vector<const char*> m_source_strings_buffer;
	std::vector<shader_lookup_entry_type> m_shader_lookup;
};
}