1 files changed, 48 insertions, 0 deletions
diff --git a/src/systems/growth.rs b/src/systems/growth.rs
new file mode 100644
index 0000000..7472115
--- /dev/null
+++ b/src/systems/growth.rs
@@ -0,0 +1,48 @@
+
+use rand;
+
+use specs::{
+	ReadStorage,
+	WriteStorage,
+	Entities,
+	System,
+	Join,
+	Write,
+	Read
+};
+
+use crate::{
+	components::{
+		Position,
+		Grow,
+		Removed
+	},
+	resources::{NewEntities, Time}
+};
+
+
+pub struct Growth;
+impl <'a> System<'a> for Growth{
+	type SystemData = (
+		Entities<'a>,
+		ReadStorage<'a, Position>,
+		Write<'a, NewEntities>,
+		WriteStorage<'a, Grow>,
+		WriteStorage<'a, Removed>,
+		Read<'a, Time>
+	);
+	
+	fn run(&mut self, (entities, positions, mut new, mut grows, mut removeds, time): Self::SystemData) {
+		for (entity, position, grow) in (&entities, &positions, &mut grows).join(){
+			if grow.target_time == None {
+				let duration = grow.delay as f64 * (1.0 + rand::random::<f64>()) / (if rand::random() {1.0} else {2.0});
+				grow.target_time = Some(time.time + duration as i64);
+			}
+			if grow.target_time.unwrap() <= time.time {
+				removeds.insert(entity, Removed).unwrap();
+				// todo: error handling
+				new.create(position.pos, grow.into.clone()).unwrap();
+			}
+		}
+	}
+}