/*
  * Copyright (c) 2006-2007 Erin Catto 
* This software is provided 'as-is', without any express or implied
* warranty.  In no event will the authors be held liable for any damages
* arising from the use of this software.
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked, and must not be
* misrepresented the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/

var b2ContactManager = Class.create();
Object.extend(b2ContactManager.prototype, b2PairCallback.prototype);
Object.extend(b2ContactManager.prototype, 
{
        initialize: function(){
                // The constructor for b2PairCallback
                //

                // initialize instance variables for references
                this.m_nullContact = new b2NullContact();
                //

                this.m_world = null;
                this.m_destroyImmediate = false;
        },

        // This is a callback from the broadphase when two AABB proxies begin
        // to overlap. We create a b2Contact to manage the narrow phase.
        PairAdded: function(proxyUserData1, proxyUserData2){
                var shape1 = proxyUserData1;
                var shape2 = proxyUserData2;

                var body1 = shape1.m_body;
                var body2 = shape2.m_body;

                if (body1.IsStatic() && body2.IsStatic())
                {
                        return this.m_nullContact;
                }

                if (shape1.m_body == shape2.m_body)
                {
                        return this.m_nullContact;
                }

                if (body2.IsConnected(body1))
                {
                        return this.m_nullContact;
                }

                if (this.m_world.m_filter != null && this.m_world.m_filter.ShouldCollide(shape1, shape2) == false)
                {
                        return this.m_nullContact;
                }

                // Ensure that body2 is dynamic (body1 is static or dynamic).
                if (body2.m_invMass == 0.0)
                {
                        var tempShape = shape1;
                        shape1 = shape2;
                        shape2 = tempShape;
                        //b2Math.b2Swap(shape1, shape2);
                        var tempBody = body1;
                        body1 = body2;
                        body2 = tempBody;
                        //b2Math.b2Swap(body1, body2);
                }

                // Call the factory.
                var contact = b2Contact.Create(shape1, shape2, this.m_world.m_blockAllocator);

                if (contact == null)
                {
                        return this.m_nullContact;
                }
                else
                {
                        // Insert into the world.
                        contact.m_prev = null;
                        contact.m_next = this.m_world.m_contactList;
                        if (this.m_world.m_contactList != null)
                        {
                                this.m_world.m_contactList.m_prev = contact;
                        }
                        this.m_world.m_contactList = contact;
                        this.m_world.m_contactCount++;
                }

                return contact;
        },

        // This is a callback from the broadphase when two AABB proxies cease
        // to overlap. We destroy the b2Contact.
        PairRemoved: function(proxyUserData1, proxyUserData2, pairUserData){

                if (pairUserData == null)
                {
                        return;
                }

                var c = pairUserData;
                if (c != this.m_nullContact)
                {
                        //b2Settings.b2Assert(this.m_world.m_contactCount > 0);
                        if (this.m_destroyImmediate == true)
                        {
                                this.DestroyContact(c);
                                c = null;
                        }
                        else
                        {
                                c.m_flags |= b2Contact.e_destroyFlag;
                        }
                }
        },

        DestroyContact: function(c)
        {

                //b2Settings.b2Assert(this.m_world.m_contactCount > 0);

                // Remove from the world.
                if (c.m_prev)
                {
                        c.m_prev.m_next = c.m_next;
                }

                if (c.m_next)
                {
                        c.m_next.m_prev = c.m_prev;
                }

                if (c == this.m_world.m_contactList)
                {
                        this.m_world.m_contactList = c.m_next;
                }

                // If there are contact points, then disconnect from the island graph.
                if (c.GetManifoldCount() > 0)
                {
                        var body1 = c.m_shape1.m_body;
                        var body2 = c.m_shape2.m_body;
                        var node1 = c.m_node1;
                        var node2 = c.m_node2;

                        // Wake up touching bodies.
                        body1.WakeUp();
                        body2.WakeUp();

                        // Remove from body 1
                        if (node1.prev)
                        {
                                node1.prev.next = node1.next;
                        }

                        if (node1.next)
                        {
                                node1.next.prev = node1.prev;
                        }

                        if (node1 == body1.m_contactList)
                        {
                                body1.m_contactList = node1.next;
                        }

                        node1.prev = null;
                        node1.next = null;

                        // Remove from body 2
                        if (node2.prev)
                        {
                                node2.prev.next = node2.next;
                        }

                        if (node2.next)
                        {
                                node2.next.prev = node2.prev;
                        }

                        if (node2 == body2.m_contactList)
                        {
                                body2.m_contactList = node2.next;
                        }

                        node2.prev = null;
                        node2.next = null;
                }

                // Call the factory.
                b2Contact.Destroy(c, this.m_world.m_blockAllocator);
                --this.m_world.m_contactCount;
        },

        // Destroy any contacts marked for deferred destruction.
        CleanContactList: function()
        {
                var c = this.m_world.m_contactList;
                while (c != null)
                {
                        var c0 = c;
                        c = c.m_next;

                        if (c0.m_flags & b2Contact.e_destroyFlag)
                        {
                                this.DestroyContact(c0);
                                c0 = null;
                        }
                }
        },

        // This is the top level collision call for the time step. Here
        // all the narrow phase collision is processed for the world
        // contact list.
        Collide: function()
        {
 
  *
  * This software is provided 'as-is', without any express or implied
  * warranty.  In no event will the authors be held liable for any damages
  * arising from the use of this software.
  * Permission is granted to anyone to use this software for any purpose,
  * including commercial applications, and to alter it and redistribute it
  * freely, subject to the following restrictions:
  * 1. The origin of this software must not be misrepresented; you must not
  * claim that you wrote the original software. If you use this software
  * in a product, an acknowledgment in the product documentation would be
  * appreciated but is not required.
  * 2. Altered source versions must be plainly marked, and must not be
  * misrepresented the original software.
  * 3. This notice may not be removed or altered from any source distribution.
  */
  
  var b2ContactManager = Class.create();
  Object.extend(b2ContactManager.prototype, b2PairCallback.prototype);
  Object.extend(b2ContactManager.prototype, 
  {
          initialize: function(){
                  // The constructor for b2PairCallback
                  //
  
                  // initialize instance variables for references
                  this.m_nullContact = new b2NullContact();
                  //
  
                  this.m_world = null;
                  this.m_destroyImmediate = false;
          },
  
          // This is a callback from the broadphase when two AABB proxies begin
          // to overlap. We create a b2Contact to manage the narrow phase.
          PairAdded: function(proxyUserData1, proxyUserData2){
                  var shape1 = proxyUserData1;
                  var shape2 = proxyUserData2;
  
                  var body1 = shape1.m_body;
                  var body2 = shape2.m_body;
  
                  if (body1.IsStatic() && body2.IsStatic())
                  {
                          return this.m_nullContact;
                  }
  
                  if (shape1.m_body == shape2.m_body)
                  {
                          return this.m_nullContact;
                  }
  
                  if (body2.IsConnected(body1))
                  {
                          return this.m_nullContact;
                  }
  
                  if (this.m_world.m_filter != null && this.m_world.m_filter.ShouldCollide(shape1, shape2) == false)
                  {
                          return this.m_nullContact;
                  }
  
                  // Ensure that body2 is dynamic (body1 is static or dynamic).
                  if (body2.m_invMass == 0.0)
                  {
                          var tempShape = shape1;
                          shape1 = shape2;
                          shape2 = tempShape;
                          //b2Math.b2Swap(shape1, shape2);
                          var tempBody = body1;
                          body1 = body2;
                          body2 = tempBody;
                          //b2Math.b2Swap(body1, body2);
                  }
  
                  // Call the factory.
                  var contact = b2Contact.Create(shape1, shape2, this.m_world.m_blockAllocator);
  
                  if (contact == null)
                  {
                          return this.m_nullContact;
                  }
                  else
                  {
                          // Insert into the world.
                          contact.m_prev = null;
                          contact.m_next = this.m_world.m_contactList;
                          if (this.m_world.m_contactList != null)
                          {
                                  this.m_world.m_contactList.m_prev = contact;
                          }
                          this.m_world.m_contactList = contact;
                          this.m_world.m_contactCount++;
                  }
  
                  return contact;
          },
  
          // This is a callback from the broadphase when two AABB proxies cease
          // to overlap. We destroy the b2Contact.
          PairRemoved: function(proxyUserData1, proxyUserData2, pairUserData){
  
                  if (pairUserData == null)
                  {
                          return;
                  }
  
                  var c = pairUserData;
                  if (c != this.m_nullContact)
                  {
                          //b2Settings.b2Assert(this.m_world.m_contactCount > 0);
                          if (this.m_destroyImmediate == true)
                          {
                                  this.DestroyContact(c);
                                  c = null;
                          }
                          else
                          {
                                  c.m_flags |= b2Contact.e_destroyFlag;
                          }
                  }
          },
  
          DestroyContact: function(c)
          {
  
                  //b2Settings.b2Assert(this.m_world.m_contactCount > 0);
  
                  // Remove from the world.
                  if (c.m_prev)
                  {
                          c.m_prev.m_next = c.m_next;
                  }
  
                  if (c.m_next)
                  {
                          c.m_next.m_prev = c.m_prev;
                  }
  
                  if (c == this.m_world.m_contactList)
                  {
                          this.m_world.m_contactList = c.m_next;
                  }
  
                  // If there are contact points, then disconnect from the island graph.
                  if (c.GetManifoldCount() > 0)
                  {
                          var body1 = c.m_shape1.m_body;
                          var body2 = c.m_shape2.m_body;
                          var node1 = c.m_node1;
                          var node2 = c.m_node2;
  
                          // Wake up touching bodies.
                          body1.WakeUp();
                          body2.WakeUp();
  
                          // Remove from body 1
                          if (node1.prev)
                          {
                                  node1.prev.next = node1.next;
                          }
  
                          if (node1.next)
                          {
                                  node1.next.prev = node1.prev;
                          }
  
                          if (node1 == body1.m_contactList)
                          {
                                  body1.m_contactList = node1.next;
                          }
  
                          node1.prev = null;
                          node1.next = null;
  
                          // Remove from body 2
                          if (node2.prev)
                          {
                                  node2.prev.next = node2.next;
                          }
  
                          if (node2.next)
                          {
                                  node2.next.prev = node2.prev;
                          }
  
                          if (node2 == body2.m_contactList)
                          {
                                  body2.m_contactList = node2.next;
                          }
  
                          node2.prev = null;
                          node2.next = null;
                  }
  
                  // Call the factory.
                  b2Contact.Destroy(c, this.m_world.m_blockAllocator);
                  --this.m_world.m_contactCount;
          },
  
          // Destroy any contacts marked for deferred destruction.
          CleanContactList: function()
          {
                  var c = this.m_world.m_contactList;
                  while (c != null)
                  {
                          var c0 = c;
                          c = c.m_next;
  
                          if (c0.m_flags & b2Contact.e_destroyFlag)
                          {
                                  this.DestroyContact(c0);
                                  c0 = null;
                          }
                  }
          },
  
          // This is the top level collision call for the time step. Here
          // all the narrow phase collision is processed for the world
          // contact list.
          Collide: function()
          {
                  var body1;
                  var body2;
                  var node1;
                  var node2;
  
                  for (var c = this.m_world.m_contactList; c != null; c = c.m_next)
                  {
                          if (c.m_shape1.m_body.IsSleeping() &&
                                  c.m_shape2.m_body.IsSleeping())
                          {
                                  continue;
                          }
  
                          var oldCount = c.GetManifoldCount();
                          c.Evaluate();
  
                          var newCount = c.GetManifoldCount();
  
                          if (oldCount == 0 && newCount > 0)
                          {
                                  //b2Settings.b2Assert(c.GetManifolds().pointCount > 0);
  
                                  // Connect to island graph.
                                  body1 = c.m_shape1.m_body;
                                  body2 = c.m_shape2.m_body;
                                  node1 = c.m_node1;
                                  node2 = c.m_node2;
  
                                  // Connect to body 1
                                  node1.contact = c;
                                  node1.other = body2;
  
                                  node1.prev = null;
                                  node1.next = body1.m_contactList;
                                  if (node1.next != null)
                                  {
                                          node1.next.prev = c.m_node1;
                                  }
                                  body1.m_contactList = c.m_node1;
  
                                  // Connect to body 2
                                  node2.contact = c;
                                  node2.other = body1;
  
                                  node2.prev = null;
                                  node2.next = body2.m_contactList;
                                  if (node2.next != null)
                                  {
                                          node2.next.prev = node2;
                                  }
                                  body2.m_contactList = node2;
                          }
                          else if (oldCount > 0 && newCount == 0)
                          {
                                  // Disconnect from island graph.
                                  body1 = c.m_shape1.m_body;
                                  body2 = c.m_shape2.m_body;
                                  node1 = c.m_node1;
                                  node2 = c.m_node2;
  
                                  // Remove from body 1
                                  if (node1.prev)
                                  {
                                          node1.prev.next = node1.next;
                                  }
  
                                  if (node1.next)
                                  {
                                          node1.next.prev = node1.prev;
                                  }
  
                                  if (node1 == body1.m_contactList)
                                  {
                                          body1.m_contactList = node1.next;
                                  }
  
                                  node1.prev = null;
                                  node1.next = null;
  
                                  // Remove from body 2
                                  if (node2.prev)
                                  {
                                          node2.prev.next = node2.next;
                                  }
  
                                  if (node2.next)
                                  {
                                          node2.next.prev = node2.prev;
                                  }
  
                                  if (node2 == body2.m_contactList)
                                  {
                                          body2.m_contactList = node2.next;
                                  }
  
                                  node2.prev = null;
                                  node2.next = null;
                          }
                  }
          },
  
          m_world: null,
  
          // This lets us provide broadphase proxy pair user data for
          // contacts that shouldn't exist.
          m_nullContact: new b2NullContact(),
          m_destroyImmediate: null});