export module runtime;

import app;

import coral;
import coral.files;
import coral.io;
import coral.math;
import coral.sequence;

import kym;
import kym.environment;

extern "C" int main(int argc, char const * const * argv) {
	return app::display("Ona Runtime", [](app::system & system, app::graphics & graphics) -> int {
		constexpr coral::path config_path{"config.kym"};
		bool is_config_loaded{false};

		system.res_fs().read_file(config_path, [&](coral::reader & file) {
			coral::allocator * const allocator{&system.thread_safe_allocator()};

			kym::vm vm{allocator, [&system](coral::slice<char const> const & error_message) {
				system.log(app::log_level::error, error_message);
			}};

			if (!vm.init({.datastack_size = 64, .callstack_size = 64})) {
				system.log(app::log_level::error, "failed to allocate memory for config vm");

				return;
			}

			coral::stack<coral::u8> script_source{allocator};
			{
				coral::u8 stream_buffer[1024]{0};
				coral::sequence_writer script_writer{&script_source};

				if (!coral::stream(script_writer, file, stream_buffer).is_ok()) return;
			}

			vm.with_object(vm.compile(coral::slice{script_source.begin(), script_source.end()}.as_chars()), [&](kym::bound_object & script) {
				vm.with_object(script.call({}), [&](kym::bound_object & config) {
					constexpr auto as_u16 = [](coral::i64 value) -> coral::optional<coral::i16> {
						if ((value >= 0) && (value <= coral::u16_max))
							return static_cast<coral::u16>(value);

						return {};
					};

					coral::u16 const width{config.get_field("width").
						as_integer().map(as_u16).value_or(0)};

					if (width == 0) return system.log(app::log_level::error,
						"failed to decode `width` property of config");

					coral::u16 const height{config.get_field("height").
						as_integer().map(as_u16).value_or(0)};

					if (height == 0) return system.log(app::log_level::error,
						"failed to decode `height` property of config");

					if (graphics.show(width, height) != app::graphics::show_result::ok)
						return system.log(app::log_level::error, "failed to initialize window");

					vm.with_object(config.get_field("title"), [&](kym::bound_object & title) {
						// TODO: implement.
						is_config_loaded = true;
					});
				});
			});
		});

		if (!is_config_loaded) {
			coral::stack<coral::u8> error_message{&system.thread_safe_allocator()};
			{
				coral::sequence_writer error_writer{&error_message};

				if (!error_writer.write(coral::slice{"failed to load "}.as_bytes()).is_ok())
					return coral::u8_max;

				if (!error_writer.write(config_path.as_slice().as_bytes()).is_ok())
					return coral::u8_max;
			}

			return coral::u8_max;
		}

		// app::canvas canvas_2d();

		while (system.poll()) {
			// canvas_2d.render(graphics);
			graphics.present();
		}

		return 0;
	});
}