/*******************************************************************************
 * Copyright (c) 2013, Daniel Murphy
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
 * 	* Redistributions of source code must retain the above copyright notice,
 * 	  this list of conditions and the following disclaimer.
 * 	* Redistributions in binary form must reproduce the above copyright notice,
 * 	  this list of conditions and the following disclaimer in the documentation
 * 	  and/or other materials provided with the distribution.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 ******************************************************************************/

package org.jbox2d.collision;

import org.jbox2d.common.MathUtils;
import org.jbox2d.common.Settings;
import org.jbox2d.common.Vec2;
import org.jbox2d.pooling.IWorldPool;
import org.jbox2d.pooling.normal.DefaultWorldPool;

/** An axis-aligned bounding box. */
public class AABB {
	/** Bottom left vertex of bounding box. */
	public final Vec2 lowerBound;
	/** Top right vertex of bounding box. */
	public final Vec2 upperBound;

	/** Creates the default object, with vertices at 0,0 and 0,0. */
	public AABB () {
		lowerBound = new Vec2();
		upperBound = new Vec2();
	}

	/** Copies from the given object
	 * 
	 * @param copy the object to copy from */
	public AABB (final AABB copy) {
		this(copy.lowerBound, copy.upperBound);
	}

	/** Creates an AABB object using the given bounding vertices.
	 * 
	 * @param lowerVertex the bottom left vertex of the bounding box
	 * @param maxVertex the top right vertex of the bounding box */
	public AABB (final Vec2 lowerVertex, final Vec2 upperVertex) {
		this.lowerBound = lowerVertex.clone(); // clone to be safe
		this.upperBound = upperVertex.clone();
	}

	/** Sets this object from the given object
	 * 
	 * @param aabb the object to copy from */
	public final void set (final AABB aabb) {
		Vec2 v = aabb.lowerBound;
		lowerBound.x = v.x;
		lowerBound.y = v.y;
		Vec2 v1 = aabb.upperBound;
		upperBound.x = v1.x;
		upperBound.y = v1.y;
	}

	/** Verify that the bounds are sorted */
	public final boolean isValid () {
		final float dx = upperBound.x - lowerBound.x;
		if (dx < 0f) {
			return false;
		}
		final float dy = upperBound.y - lowerBound.y;
		if (dy < 0) {
			return false;
		}
		return lowerBound.isValid() && upperBound.isValid();
	}

	/** Get the center of the AABB
	 * 
	 * @return */
	public final Vec2 getCenter () {
		final Vec2 center = new Vec2(lowerBound);
		center.addLocal(upperBound);
		center.mulLocal(.5f);
		return center;
	}

	public final void getCenterToOut (final Vec2 out) {
		out.x = (lowerBound.x + upperBound.x) * .5f;
		out.y = (lowerBound.y + upperBound.y) * .5f;
	}

	/** Get the extents of the AABB (half-widths).
	 * 
	 * @return */
	public final Vec2 getExtents () {
		final Vec2 center = new Vec2(upperBound);
		center.subLocal(lowerBound);
		center.mulLocal(.5f);
		return center;
	}

	public final void getExtentsToOut (final Vec2 out) {
		out.x = (upperBound.x - lowerBound.x) * .5f;
		out.y = (upperBound.y - lowerBound.y) * .5f; // thanks FDN1
	}

	public final void getVertices (Vec2[] argRay) {
		argRay[0].set(lowerBound);
		argRay[1].set(lowerBound);
		argRay[1].x += upperBound.x - lowerBound.x;
		argRay[2].set(upperBound);
		argRay[3].set(upperBound);
		argRay[3].x -= upperBound.x - lowerBound.x;
	}

	/** Combine two AABBs into this one.
	 * 
	 * @param aabb1
	 * @param aab */
	public final void combine (final AABB aabb1, final AABB aab) {
		lowerBound.x = aabb1.lowerBound.x < aab.lowerBound.x ? aabb1.lowerBound.x : aab.lowerBound.x;
		lowerBound.y = aabb1.lowerBound.y < aab.lowerBound.y ? aabb1.lowerBound.y : aab.lowerBound.y;
		upperBound.x = aabb1.upperBound.x > aab.upperBound.x ? aabb1.upperBound.x : aab.upperBound.x;
		upperBound.y = aabb1.upperBound.y > aab.upperBound.y ? aabb1.upperBound.y : aab.upperBound.y;
	}

	/** Gets the perimeter length
	 * 
	 * @return */
	public final float getPerimeter () {
		return 2.0f * (upperBound.x - lowerBound.x + upperBound.y - lowerBound.y);
	}

	/** Combines another aabb with this one
	 * 
	 * @param aabb */
	public final void combine (final AABB aabb) {
		lowerBound.x = lowerBound.x < aabb.lowerBound.x ? lowerBound.x : aabb.lowerBound.x;
		lowerBound.y = lowerBound.y < aabb.lowerBound.y ? lowerBound.y : aabb.lowerBound.y;
		upperBound.x = upperBound.x > aabb.upperBound.x ? upperBound.x : aabb.upperBound.x;
		upperBound.y = upperBound.y > aabb.upperBound.y ? upperBound.y : aabb.upperBound.y;
	}

	/** Does this aabb contain the provided AABB.
	 * 
	 * @return */
	public final boolean contains (final AABB aabb) {
		/*
		 * boolean result = true; result = result && lowerBound.x <= aabb.lowerBound.x; result = result && lowerBound.y <=
		 * aabb.lowerBound.y; result = result && aabb.upperBound.x <= upperBound.x; result = result && aabb.upperBound.y <=
		 * upperBound.y; return result;
		 */
		// djm: faster putting all of them together, as if one is false we leave the logic
		// early
		return lowerBound.x <= aabb.lowerBound.x && lowerBound.y <= aabb.lowerBound.y && aabb.upperBound.x <= upperBound.x
			&& aabb.upperBound.y <= upperBound.y;
	}

	/** @deprecated please use {@link #raycast(RayCastOutput, RayCastInput, IWorldPool)} for better performance
	 * @param output
	 * @param input
	 * @return */
	public final boolean raycast (final RayCastOutput output, final RayCastInput input) {
		return raycast(output, input, new DefaultWorldPool(4, 4));
	}

	/** From Real-time Collision Detection, p179.
	 * 
	 * @param output
	 * @param input */
	public final boolean raycast (final RayCastOutput output, final RayCastInput input, IWorldPool argPool) {
		float tmin = -Float.MAX_VALUE;
		float tmax = Float.MAX_VALUE;

		final Vec2 p = argPool.popVec2();
		final Vec2 d = argPool.popVec2();
		final Vec2 absD = argPool.popVec2();
		final Vec2 normal = argPool.popVec2();

		p.set(input.p1);
		d.set(input.p2).subLocal(input.p1);
		Vec2.absToOut(d, absD);

		// x then y
		if (absD.x < Settings.EPSILON) {
			// Parallel.
			if (p.x < lowerBound.x || upperBound.x < p.x) {
				argPool.pushVec2(4);
				return false;
			}
		} else {
			final float inv_d = 1.0f / d.x;
			float t1 = (lowerBound.x - p.x) * inv_d;
			float t2 = (upperBound.x - p.x) * inv_d;

			// Sign of the normal vector.
			float s = -1.0f;

			if (t1 > t2) {
				final float temp = t1;
				t1 = t2;
				t2 = temp;
				s = 1.0f;
			}

			// Push the min up
			if (t1 > tmin) {
				normal.setZero();
				normal.x = s;
				tmin = t1;
			}

			// Pull the max down
			tmax = MathUtils.min(tmax, t2);

			if (tmin > tmax) {
				argPool.pushVec2(4);
				return false;
			}
		}

		if (absD.y < Settings.EPSILON) {
			// Parallel.
			if (p.y < lowerBound.y || upperBound.y < p.y) {
				argPool.pushVec2(4);
				return false;
			}
		} else {
			final float inv_d = 1.0f / d.y;
			float t1 = (lowerBound.y - p.y) * inv_d;
			float t2 = (upperBound.y - p.y) * inv_d;

			// Sign of the normal vector.
			float s = -1.0f;

			if (t1 > t2) {
				final float temp = t1;
				t1 = t2;
				t2 = temp;
				s = 1.0f;
			}

			// Push the min up
			if (t1 > tmin) {
				normal.setZero();
				normal.y = s;
				tmin = t1;
			}

			// Pull the max down
			tmax = MathUtils.min(tmax, t2);

			if (tmin > tmax) {
				argPool.pushVec2(4);
				return false;
			}
		}

		// Does the ray start inside the box?
		// Does the ray intersect beyond the max fraction?
		if (tmin < 0.0f || input.maxFraction < tmin) {
			argPool.pushVec2(4);
			return false;
		}

		// Intersection.
		output.fraction = tmin;
		output.normal.x = normal.x;
		output.normal.y = normal.y;
		argPool.pushVec2(4);
		return true;
	}

	public static final boolean testOverlap (final AABB a, final AABB b) {
		if (b.lowerBound.x - a.upperBound.x > 0.0f || b.lowerBound.y - a.upperBound.y > 0.0f) {
			return false;
		}

		if (a.lowerBound.x - b.upperBound.x > 0.0f || a.lowerBound.y - b.upperBound.y > 0.0f) {
			return false;
		}

		return true;
	}

	@Override
	public final String toString () {
		final String s = "AABB[" + lowerBound + " . " + upperBound + "]";
		return s;
	}
}
