use super::RadianPoint;

fn wrap_longitude(lambda: f32) -> f32 {
	use std::f32::consts::PI;

	if lambda.abs() <= PI {
		lambda
	} else {
		lambda.signum() * ((lambda.abs() + PI) % (2.0 * PI) - PI)
	}
}

pub fn polygon_contains_south(polygon: &[Vec<RadianPoint>]) -> bool {
	let mut angle_sum = 0.0;
	for ring in polygon {
		if let Some(mut prev) = ring.last() {
			for point in ring {
				angle_sum += wrap_longitude(point.lambda - prev.lambda);
				prev = point;
			}
		}
	}

	angle_sum < -std::f32::consts::PI
}