use glyphon::{Attrs, Buffer, Color, Family, Metrics, Shaping, TextArea, TextBounds};

use crate::{RenderInput, RenderState};

pub(super) struct FpsIndicator {
	buffer: Buffer,
	update_counter: u32,
}

impl FpsIndicator {
	pub fn new(state: &mut RenderState) -> Self {
		let mut buffer = Buffer::new(&mut state.text_font_system, Metrics::new(15.0, 20.0));
		buffer.set_size(
			&mut state.text_font_system,
			state.window_size.width as f32,
			state.window_size.height as f32,
		);
		buffer.shape_until_scroll(&mut state.text_font_system);

		Self {
			buffer,
			update_counter: 0,
		}
	}
}

impl FpsIndicator {
	pub fn update(&mut self, input: &RenderInput, state: &mut RenderState) {
		// Update once every n frames
		if self.update_counter > 0 {
			self.update_counter -= 1;
			return;
		}
		self.update_counter = 100;

		self.buffer.set_text(
			&mut state.text_font_system,
			&format!(
				"Frame:  {:#?} ({:05.00})\nShips:  {:05.02}%\nPhys:   {:05.02}%\n",
				input.timing.frame,
				1.0 / input.timing.frame.as_secs_f32(),
				100.0 * (input.timing.physics_sim.as_secs_f32() / input.timing.frame.as_secs_f32()),
				100.0
					* (input.timing.physics_ship.as_secs_f32() / input.timing.frame.as_secs_f32()),
			),
			Attrs::new().family(Family::Monospace),
			Shaping::Basic,
		);
	}

	pub fn get_textarea(&self) -> TextArea {
		TextArea {
			buffer: &self.buffer,
			left: 10.0,
			top: 400.0,
			scale: 1.0,
			bounds: TextBounds {
				left: 10,
				top: 400,
				right: 300,
				bottom: 800,
			},
			default_color: Color::rgb(255, 255, 255),
		}
	}
}