//! Keep track of the time we spent in each part of the game loop.
use std::time::Instant;

/// Utility struct.
/// Keeps track of the time we spent in each part of the game loop.
#[derive(Debug)]
pub struct Timing {
	/// The time we spent processing the whole frame
	pub frame: f32,
	frame_timer: Instant,

	/// The time we spent simulating game state
	pub galaxy: f32,
	galaxy_timer: Instant,

	/// The time we spent simulating physics
	pub physics_sim: f32,
	physics_sim_timer: Instant,

	/// The time we spent updating physics ships
	pub physics_ship: f32,
	physics_ship_timer: Instant,

	/// The time we spent simulating physics
	pub render: f32,
	render_timer: Instant,
}

// TODO: macros
// TODO: document each duration

impl Timing {
	/// Create a new timing struct
	pub fn new() -> Self {
		Self {
			frame: f32::NAN,
			galaxy: f32::NAN,
			physics_sim: f32::NAN,
			physics_ship: f32::NAN,
			render: f32::NAN,
			galaxy_timer: Instant::now(),
			physics_sim_timer: Instant::now(),
			physics_ship_timer: Instant::now(),
			render_timer: Instant::now(),
			frame_timer: Instant::now(),
		}
	}

	/// Start frame timer
	pub fn start_frame(&mut self) {
		self.frame_timer = Instant::now();
	}

	/// Start galaxy timer
	pub fn start_galaxy(&mut self) {
		self.galaxy_timer = Instant::now();
	}

	/// Start physics sim timer
	pub fn start_physics_sim(&mut self) {
		self.physics_sim_timer = Instant::now();
	}

	/// Start physics ship timer
	pub fn start_physics_ships(&mut self) {
		self.physics_ship_timer = Instant::now();
	}

	/// Start render timer
	pub fn start_render(&mut self) {
		self.render_timer = Instant::now();
	}

	/// Record galaxy simulation time.
	pub fn mark_frame(&mut self) {
		self.frame = self.frame_timer.elapsed().as_secs_f32();
	}

	/// Record galaxy simulation time.
	pub fn mark_galaxy(&mut self) {
		self.galaxy = self.galaxy_timer.elapsed().as_secs_f32();
	}

	/// Record physics simulation time
	pub fn mark_physics_sim(&mut self) {
		self.physics_sim = self.physics_sim_timer.elapsed().as_secs_f32();
	}

	/// Record physics ship update time
	pub fn mark_physics_ships(&mut self) {
		self.physics_ship = self.physics_ship_timer.elapsed().as_secs_f32();
	}

	/// Record physics simulation time
	pub fn mark_render(&mut self) {
		self.render = self.render_timer.elapsed().as_secs_f32();
	}
}