use rand;

use specs::{
	WriteStorage,
	Entities,
	System,
	Join,
	Read
};

use crate::{
	components::{
		Grow,
		TimeOffset,
		TriggerBox
	},
	resources::{Time}
};


pub struct Growth;
impl <'a> System<'a> for Growth{
	type SystemData = (
		Entities<'a>,
		WriteStorage<'a, Grow>,
		WriteStorage<'a, TriggerBox>,
		Read<'a, Time>,
		WriteStorage<'a, TimeOffset>
	);
	
	fn run(&mut self, (entities, mut grows, mut triggerboxes, time, mut time_offsets): Self::SystemData) {
		for (entity, grow) in (&entities, &mut grows).join(){
			if grow.target_time == None {
				let creation_time = time.time + time_offsets.get(entity).map(|ct| ct.dtime).unwrap_or(0);
				let mut r = 1.0 - rand::random::<f64>() * grow.spread;
				if rand::random() {
					r = 1.0 / r;
				}
				let duration = (grow.delay as f64 * r + 0.4) as i64;
				grow.target_time = Some(creation_time + duration);
			}
			let target_time = grow.target_time.unwrap();
			if target_time <= time.time {
				if target_time < time.time {
					time_offsets.insert(entity, TimeOffset{dtime: target_time.0 - time.time.0}).unwrap();
				} else {
					time_offsets.remove(entity);
				}
				TriggerBox::add_message(&mut triggerboxes, entity, grow.trigger);
				grow.target_time = None;
			}
		}
	}
}