#pragma once

#include <filesystem>

#include "assets/path_id_lookups.hpp"
#include "assets/data_stores/shader_source_store.hpp"
#include "assets/data/shader_source_data.hpp"

namespace assets
{

struct glsl_parser
{
	static constexpr auto name = std::string_view("glsl");
	using data_type = shader_source_data;
	using store_type = shader_source_store;
	using lookup_type = shader_source_id_lookup;

	[[nodiscard]] std::error_code prefetch(
		path_id_lookups& lookups
	);

	[[nodiscard]] std::error_code load(
		const path_id_lookups& lookups,
		store_type& store,
		bool pedantic = false
	);

protected:
	class parser_context
	{
	public:
		parser_context(store_type& m_store);

		void operator()(lookup_type::const_pointer entry) noexcept;

	protected:
		void reset();

		void tokenize_declarations();

		[[nodiscard]] bool parse_metadata_from_tokens();

		void remove_metadata_declarations();

	private:
		store_type* m_store;
		shader_source_data m_buffer{};
		std::vector<std::string_view> m_value_buffer{};
		std::vector<std::size_t> m_declaration_value_count_buffer{};
		std::array<std::size_t, 4> m_declaration_type_index_buffer{};
	};

	[[nodiscard]] static std::error_code read_file(
		const std::filesystem::path& filename,
		std::vector<char>& source
	);

	[[nodiscard]] static bool parse_geometry_declaration(
		std::span<const std::string_view> values,
		shader_source_data::metadata& meta
	);

	[[nodiscard]] static bool parse_stage_declaration(
		std::span<const std::string_view> values,
		shader_source_data::metadata& meta
	);

	[[nodiscard]] static bool parse_components_declaration(
		std::span<const std::string_view> values,
		shader_source_data::metadata& meta
	);

	[[nodiscard]] static bool parse_static_enable_declaration(
		std::span<const std::string_view> values,
		shader_source_data::metadata& meta
	);

	[[nodiscard]] static bool parse_dynamic_enable_declaration(
		std::span<const std::string_view> values,
		shader_source_data::metadata& meta
	);

	[[nodiscard]] static bool parse_component_tokens(
		std::span<const std::string_view> values,
		model_geometry::types geometry_type,
		shader_components::flags& components
	);

private:
	std::vector<std::string_view> m_value_token_buffer;
	std::vector<std::size_t> m_declaration_token_count_buffer;
	std::array<std::size_t, 4> m_declaration_type_index_buffer;
	std::vector<lookup_type::const_pointer> m_path_buffer;
};

}