// Copyright Jeron A. Lau 2017-2018.
// Copyright Douglas Lau 2017
// Dual-licensed under either the MIT License or the Boost Software License,
// Version 1.0.  (See accompanying file LICENSE_1_0.txt or copy at
// https://www.boost.org/LICENSE_1_0.txt)

// TODO: this thing.

use std::fmt;

use Vec3;

/// Bounding sphere
#[derive(Clone, Copy)]
pub struct BSphere {
	pub(crate) center: Vec3,
	pub(crate) half_d: Vec3,
}

impl fmt::Debug for BBox {
	fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
		write!(f, "{:?}±{:?}", self.center, self.half_d)
	}
}

impl BBox {
	/// Create an new `BBox` at position `p`.
	pub fn new(p: Vec3) -> BBox {
		BBox { center: p, half_len: 1.0 }
	}

	fn min_p(&self) -> f32 {
		if self.half_len > 0.0 {
			self.center.min_p() - self.half_len
		} else {
			self.center.min_p()
		}
	}

	fn max_p(&self) -> f32 {
		if self.half_len > 0.0 {
			self.center.max_p() + self.half_len
		} else {
			self.center.max_p()
		}
	}

	fn move_center(&self, p: Vec3) -> Vec3 {
		let min_p = self.min_p();
		if p.min_p() < min_p {
			return Vec3::new(min_p, min_p, min_p);
		} else {
			let max_p = self.max_p();
			return Vec3::new(max_p, max_p, max_p);
		}
	}

	/// Check if `BBox` contains point `p`.
	pub fn contains(&self, p: Vec3) -> bool {
		let Vec3 { x, y, z } = self.center;
		let hl = self.half_len;
		(p.x >= x - hl) &&
		(p.x <  x + hl) &&
		(p.y >= y - hl) &&
		(p.y <  y + hl) &&
		(p.z >= z - hl) &&
		(p.z <  z + hl)
	}

	/// Get two opposite points that are the bounds of the BBox.
	pub fn to_point_pair(&self) -> (Vec3, Vec3) {
		let half_box = Vec3::new(self.half_len, self.half_len,
			self.half_len);

		(self.center + half_box, self.center - half_box)
	}

	/// Get all 6 points or the `BBox`.
	pub fn all_points(&self) -> [Vec3; 7] {
		let z = 0.0;

		[
			self.center,
			self.center + Vec3::new(self.half_len, z, z),
			self.center + Vec3::new(z, self.half_len, z),
			self.center + Vec3::new(z, z, self.half_len),
			self.center + Vec3::new(-self.half_len, z, z),
			self.center + Vec3::new(z, -self.half_len, z),
			self.center + Vec3::new(z, z, -self.half_len),
		]
	}

	/// Get a positive and negative pair of opposite points that are the
	/// bounds of the BBox, based around a normal.
	pub fn pn_pair_from_normal(&self, normal: Vec3)
		-> (Vec3, Vec3)
	{
		let mut pvertex = self.center;
		let mut nvertex = self.center;

		if normal.x >= 0.0 {
			pvertex.x += self.half_len;
			nvertex.x -= self.half_len;
		} else {
			nvertex.x += self.half_len;
			pvertex.x -= self.half_len;
		}

		if normal.y >= 0.0 {
			pvertex.y += self.half_len;
			nvertex.y -= self.half_len;
		} else {
			nvertex.y += self.half_len;
			pvertex.y -= self.half_len;
		}

		if normal.z >= 0.0 {
			pvertex.z += self.half_len;
			nvertex.z -= self.half_len;
		} else {

		(nvertex, pvertex)
	}
}


			nvertex.z += self.half_len;
			pvertex.z -= self.half_len;
		}
