/*******************************************************************************
 * 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.dynamics.joints;

import org.jbox2d.common.Vec2;
import org.jbox2d.dynamics.Body;
import org.jbox2d.dynamics.SolverData;
import org.jbox2d.dynamics.World;
import org.jbox2d.pooling.IWorldPool;

// updated to rev 100
/** The base joint class. Joints are used to constrain two bodies together in various fashions. Some joints also feature limits
 * and motors.
 * 
 * @author Daniel Murphy */
public abstract class Joint {

	public static Joint create (World world, JointDef def) {
		// Joint joint = null;
		switch (def.type) {
		case MOUSE:
			return new MouseJoint(world.getPool(), (MouseJointDef)def);
		case DISTANCE:
			return new DistanceJoint(world.getPool(), (DistanceJointDef)def);
		case PRISMATIC:
			return new PrismaticJoint(world.getPool(), (PrismaticJointDef)def);
		case REVOLUTE:
			return new RevoluteJoint(world.getPool(), (RevoluteJointDef)def);
		case WELD:
			return new WeldJoint(world.getPool(), (WeldJointDef)def);
		case FRICTION:
			return new FrictionJoint(world.getPool(), (FrictionJointDef)def);
		case WHEEL:
			return new WheelJoint(world.getPool(), (WheelJointDef)def);
		case GEAR:
			return new GearJoint(world.getPool(), (GearJointDef)def);
		case PULLEY:
			return new PulleyJoint(world.getPool(), (PulleyJointDef)def);
		case CONSTANT_VOLUME:
			return new ConstantVolumeJoint(world, (ConstantVolumeJointDef)def);
		case ROPE:
			return new RopeJoint(world.getPool(), (RopeJointDef)def);
		case MOTOR:
			return new MotorJoint(world.getPool(), (MotorJointDef)def);
		case UNKNOWN:
		default:
			return null;
		}
	}

	public static void destroy (Joint joint) {
		joint.destructor();
	}

	private final JointType m_type;
	public Joint m_prev;
	public Joint m_next;
	public JointEdge m_edgeA;
	public JointEdge m_edgeB;
	protected Body m_bodyA;
	protected Body m_bodyB;

	public boolean m_islandFlag;
	private boolean m_collideConnected;

	public Object m_userData;

	protected IWorldPool pool;

	// Cache here per time step to reduce cache misses.
	// final Vec2 m_localCenterA, m_localCenterB;
	// float m_invMassA, m_invIA;
	// float m_invMassB, m_invIB;

	protected Joint (IWorldPool worldPool, JointDef def) {
		assert (def.bodyA != def.bodyB);

		pool = worldPool;
		m_type = def.type;
		m_prev = null;
		m_next = null;
		m_bodyA = def.bodyA;
		m_bodyB = def.bodyB;
		m_collideConnected = def.collideConnected;
		m_islandFlag = false;
		m_userData = def.userData;

		m_edgeA = new JointEdge();
		m_edgeA.joint = null;
		m_edgeA.other = null;
		m_edgeA.prev = null;
		m_edgeA.next = null;

		m_edgeB = new JointEdge();
		m_edgeB.joint = null;
		m_edgeB.other = null;
		m_edgeB.prev = null;
		m_edgeB.next = null;

		// m_localCenterA = new Vec2();
		// m_localCenterB = new Vec2();
	}

	/** get the type of the concrete joint.
	 * 
	 * @return */
	public JointType getType () {
		return m_type;
	}

	/** get the first body attached to this joint. */
	public final Body getBodyA () {
		return m_bodyA;
	}

	/** get the second body attached to this joint.
	 * 
	 * @return */
	public final Body getBodyB () {
		return m_bodyB;
	}

	/** get the anchor point on bodyA in world coordinates.
	 * 
	 * @return */
	public abstract void getAnchorA (Vec2 out);

	/** get the anchor point on bodyB in world coordinates.
	 * 
	 * @return */
	public abstract void getAnchorB (Vec2 out);

	/** get the reaction force on body2 at the joint anchor in Newtons.
	 * 
	 * @param inv_dt
	 * @return */
	public abstract void getReactionForce (float inv_dt, Vec2 out);

	/** get the reaction torque on body2 in N*m.
	 * 
	 * @param inv_dt
	 * @return */
	public abstract float getReactionTorque (float inv_dt);

	/** get the next joint the world joint list. */
	public Joint getNext () {
		return m_next;
	}

	/** get the user data pointer. */
	public Object getUserData () {
		return m_userData;
	}

	/** Set the user data pointer. */
	public void setUserData (Object data) {
		m_userData = data;
	}

	/** Get collide connected. Note: modifying the collide connect flag won't work correctly because the flag is only checked when
	 * fixture AABBs begin to overlap. */
	public final boolean getCollideConnected () {
		return m_collideConnected;
	}

	/** Short-cut function to determine if either body is inactive.
	 * 
	 * @return */
	public boolean isActive () {
		return m_bodyA.isActive() && m_bodyB.isActive();
	}

	/** Internal */
	public abstract void initVelocityConstraints (SolverData data);

	/** Internal */
	public abstract void solveVelocityConstraints (SolverData data);

	/** This returns true if the position errors are within tolerance. Internal. */
	public abstract boolean solvePositionConstraints (SolverData data);

	/** Override to handle destruction of joint */
	public void destructor () {
	}
}
