/*
 * Copyright (c) Contributors, https://github.com/jonc/osboids
 * https://github.com/JakDaniels/OpenSimBirds
 * See CONTRIBUTORS.TXT for a full list of copyright holders.
 *
 * 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.
 *     * Neither the name of the OpenSimulator Project nor the
 *       names of its contributors may be used to endorse or promote products
 *       derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``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 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.
 */

using System;
using System.Collections.Generic;
using OpenMetaverse;
using OpenSim.Region.Framework.Scenes;

namespace Flocking
{
	public class FlowMap
	{
		private Scene m_scene;
        private uint regionX;
        private uint regionY;
        private uint regionZ;
        private float regionBorder;

		private List<FlowEntry> m_flowMap = new List<FlowEntry>();

		public FlowMap (Scene scene, int maxHeight, float borderSize)
		{
			m_scene = scene;
            regionX = m_scene.RegionInfo.RegionSizeX;
            regionY = m_scene.RegionInfo.RegionSizeY;
            regionZ = (uint)maxHeight;
            regionBorder = borderSize;
		}
		
		public int LengthX {
			get {return (int)regionX;}
		}
		public int LengthY {
			get {return (int)regionY;}
		}
		public int LengthZ {
			get {return (int)regionZ;}
		}
        public int Border  {
            get {return (int)regionBorder;}
        }
		
		public void Initialise() {
			//fill in the boundaries
			for( int x = 0; x < regionX; x++ ) {
				for( int y = 0; y < regionY; y++ ) {
					m_flowMap.Add(new FlowEntry(x, y, 0, 100));
					m_flowMap.Add(new FlowEntry(x, y, regionZ - 1, 100));
				}
			}
			for( int x = 0; x < regionX; x++ ) {
				for( int z = 0; z < regionZ; z++ ) {
					m_flowMap.Add(new FlowEntry(x, 0, z, 100));
					m_flowMap.Add(new FlowEntry(x, regionY - 1, z, 100));
				}
			}
			for( int y = 0; y < regionY; y++ ) {
				for( int z = 0; z < regionZ; z++ ) {
					m_flowMap.Add(new FlowEntry(0, y, z, 100));
					m_flowMap.Add(new FlowEntry(regionX - 1, y, z, 100));
				}
			}
			
			//fill in the terrain
			for( int x = 0; x < regionX; x++ ) {
				for( int y = 0; y < regionY; y++ ) {
					int zMax = Convert.ToInt32(m_scene.GetGroundHeight( x, y ));
					for( int z = 1; z < zMax; z++ ) {
						if (x < regionX && y < regionY && z < zMax)
							m_flowMap.Add(new FlowEntry(x, y, z, 100));
					}
				}
			}
			
			// fill in the things
			foreach( EntityBase entity in m_scene.GetEntities() ) {
				if( entity is SceneObjectGroup ) {
					SceneObjectGroup sog = (SceneObjectGroup)entity;

					if (sog.IsPhantom)
						continue;

					float fmaxX, fminX, fmaxY, fminY, fmaxZ, fminZ;
					int maxX, minX, maxY, minY, maxZ, minZ;
					sog.GetAxisAlignedBoundingBoxRaw( out fminX, out fmaxX, out fminY, out fmaxY, out fminZ, out fmaxZ );
					
					minX = Convert.ToInt32(fminX);
					maxX = Convert.ToInt32(fmaxX);
					minY = Convert.ToInt32(fminY);
					maxY = Convert.ToInt32(fmaxX);
					minZ = Convert.ToInt32(fminZ);
					maxZ = Convert.ToInt32(fmaxZ);
					
					for( int x = minX; x < maxX; x++ ) {
						for( int y = minY; y < maxY; y++ ) {
							for( int z = minZ; z < maxZ; z++ ) {
								if(x < maxX && y < maxY && z < maxX)
									m_flowMap.Add(new FlowEntry(x, y, z, 100));
							}
						}
					}
				}
			}
		}

		public bool WouldHitObstacle (Vector3 currPos, Vector3 targetPos)
		{
			bool retVal = false;
			//fail fast
			if( IsOutOfBounds(targetPos) ) {
				retVal = true;
			} else if( IsWithinObstacle(targetPos) ) {
				retVal = true;
			} else if( IntersectsObstacle (currPos, targetPos) ) {
				retVal = true;
			}
			
			return retVal;
		}
		
		public bool IsOutOfBounds(Vector3 targetPos) {
			bool retVal = false;
			if( targetPos.X < regionBorder ||
				targetPos.X > regionX - regionBorder ||
                targetPos.Y < regionBorder ||
				targetPos.Y > regionY - regionBorder ||
				targetPos.Z < regionBorder ||
				targetPos.Z > regionZ - regionBorder ) {
				
				retVal = true;
			}
			
			return retVal;
		}

		public bool IntersectsObstacle (Vector3 currPos, Vector3 targetPos)
		{
			bool retVal = false;
			// Ray trace the Vector and fail as soon as we hit something
			Vector3 direction = targetPos - currPos;
			float length = direction.Length();
			// check every metre
			for( float i = 1f; i < length; i += 1f ) {
				Vector3 rayPos = currPos + ( direction * i );
				//give up if we go OOB on this ray
				if( IsOutOfBounds( rayPos ) ){ 
					retVal = true;
					break;
				}
				else if( IsWithinObstacle( rayPos ) ) {
					retVal = true;
					break;
				}
			}
			
			return retVal;
		}
		
		public bool IsWithinObstacle( Vector3 targetPos ) {
			return IsWithinObstacle(Convert.ToInt32(targetPos.X), Convert.ToInt32(targetPos.Y),Convert.ToInt32(targetPos.Z));
		}
		
		public bool IsWithinObstacle( int x, int y, int z ) {
			bool retVal = false;

			FlowEntry flow = m_flowMap.Find(X => X.X == x && X.Y == y && X.Z == z);

			if (flow == null)
				return retVal;

			if (x >= LengthX || y >= LengthY || z >= LengthZ)
            {
				retVal = true;
            }
            else if (x < 0 || y < 0 || z < 0)
            {
				retVal = true;
			} else if (flow.Value > 50) {
				retVal = true;
			}
			return retVal;	
		}
	}
	
	
}