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

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

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

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

// TODO: document each duration

impl Timing {
	/// Create a new timing struct
	pub fn new() -> Self {
		Self {
			frame: Duration::ZERO,
			physics_sim: Duration::ZERO,
			physics_ship: Duration::ZERO,
			physics_sim_timer: Instant::now(),
			physics_ship_timer: Instant::now(),
			frame_timer: Instant::now(),
		}
	}

	/// Start frame timer
	pub fn start_frame(&mut self) {
		self.frame_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();
	}

	/// Record total frame compute time
	pub fn mark_frame(&mut self) {
		self.frame = self.frame_timer.elapsed();
	}

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

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