#pragma once

#include <filesystem>
#include <system_error>
#include <string_view>
#include "assets/data/mesh_data.hpp"
#include "assets/data_stores.hpp"
#include "assets/path_id_lookups.hpp"
#include <unordered_map>
#include "util/array_hash.hpp"

namespace assets::obj_parser_error
{
enum class codes {
	ok = 0,
	cannot_open_file,
	malformed_vertex,
	malformed_texture_coordinate,
	malformed_normal,
	malformed_face,
	face_index_out_of_range,
	unknown_line_begin,
	use_material_without_material_library,
	unknown_material_name
};
} // namespace obj_loader_error

namespace assets
{

struct obj_parser
{
	static constexpr auto name = std::string_view("obj");
	using data_type = mesh_data;
	using store_type = mesh_store;
	using lookup_type = mesh_id_lookup;

	// TODO port this mess to the new interface
	[[nodiscard]] std::error_code prefetch(
		path_id_lookups& lookups
	);

	[[nodiscard]] std::error_code load(
		path_id_lookups& lookups,
		data_stores& stores,
		bool pedantic = false
	);

protected:
	using component_indices = std::array<z3d::vertex_index, 3>;

	class prefetcher_context
	{
	public:
		prefetcher_context(
			path_id_lookups& id_lookups
		);

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

	private:
		path_id_lookups* m_id_lookups;
		std::vector<char> m_buffer{};
	};

	class parser_context
	{
	public:
		parser_context(
			path_id_lookups& m_id_lookups,
			data_stores& m_stores
		);

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

	protected:
		void reset();

		z3d::vertex_index find_or_push_vertex(const component_indices& vertex_comp_indices);

		[[nodiscard]] std::optional<texture_id> fetch_texture_id(
			const std::filesystem::path& mtl_dir,
			std::string_view filename,
			std::string_view texture_type_name
		);

	private:
		path_id_lookups* m_id_lookups;
		data_stores* m_stores;
		data_type m_mesh{};
		std::vector<mesh_vertex_components::position> m_position_buffer{};
		std::vector<mesh_vertex_components::normal> m_normal_buffer{};
		std::vector<mesh_vertex_components::tex_coord> m_tex_coord_buffer{};
		std::unordered_map<component_indices, z3d::vertex_index> m_vertex_comp_indices_to_vertex_index{};
	};

private:
	std::vector<lookup_type::const_pointer> m_path_buffer;
};
}