///
///    This file is part of ILNumerics Community Edition.
///
///    ILNumerics Community Edition - high performance computing for applications.
///    Copyright (C) 2006 - 2012 Haymo Kutschbach, http://ilnumerics.net
///
///    ILNumerics Community Edition is free software: you can redistribute it and/or modify
///    it under the terms of the GNU General Public License version 3 as published by
///    the Free Software Foundation.
///
///    ILNumerics Community Edition is distributed in the hope that it will be useful,
///    but WITHOUT ANY WARRANTY; without even the implied warranty of
///    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
///    GNU General Public License for more details.
///
///    You should have received a copy of the GNU General Public License
///    along with ILNumerics Community Edition. See the file License.txt in the root
///    of your distribution package. If not, see <http://www.gnu.org/licenses/>.
///
///    In addition this software uses the following components and/or licenses: 
///
///    =================================================================================
///    The Open Toolkit Library License
///    
///    Copyright (c) 2006 - 2009 the Open Toolkit library.
///    
///    Permission is hereby granted, free of charge, to any person obtaining a copy
///    of this software and associated documentation files (the "Software"), to deal
///    in the Software without restriction, including without limitation the rights to 
///    use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
///    the Software, and to permit persons to whom the Software is furnished to do
///    so, subject to the following conditions:
///
///    The above copyright notice and this permission notice shall be included in all
///    copies or substantial portions of the Software.
///
///    =================================================================================
///    

using System;
using System.Collections.Generic;
using System.Collections;
using System.Text;
using ILNumerics.Drawing.Collections; 
using ILNumerics.Drawing.Shapes; 
using ILNumerics.Drawing; 

namespace ILNumerics.Drawing.Graphs {
    /// <summary>
    /// abstract base class for all scene graph nodes
    /// </summary>
    public abstract class ILSceneGraphNode : 
                //ICollection<ILSceneGraphNode>,
                IEnumerable<ILSceneGraphNode>
                ,IEnumerable {
        
        #region attributes 
        protected ILSceneGraphNode m_parent; 
        protected ILPoint3Df m_center;
        protected ILPoint3Df m_positionMin; 
        protected ILPoint3Df m_positionMax; 
        protected bool m_invalidated;
        protected bool m_visible;
        protected ILPanel m_panel; // needed for camera position
        protected bool m_eventingSuspended; 
        #endregion

        #region constructors
        internal ILSceneGraphNode(ILPanel panel) {
            m_panel = panel; 
            m_invalidated = true;
            m_visible = true; 
        }
        #endregion

        #region eventing
        /// <summary>
        /// fires when the size of the cube tigthly enclosing the shape has changed
        /// </summary>
        public event EventHandler SizeChanged;
        protected virtual void OnSizeChanged() {
            if (SizeChanged != null && !m_eventingSuspended)
                SizeChanged(this, new EventArgs());
        }
        /// <summary>
        /// fires when the (size)cache of the node was invalidated
        /// </summary>
        public event EventHandler Invalidated;
        protected virtual void OnInvalidated() {
            if (Invalidated != null && !m_eventingSuspended)
                Invalidated(this, new EventArgs());
        }
        protected virtual void OnNodeAdded(ILSceneGraphNode node) {
            if (m_parent != null && !m_eventingSuspended) {
                m_parent.OnNodeAdded(node); 
            }
        }
        protected virtual void OnNodeRemoved(ILSceneGraphNode node) {
            if (m_parent != null && !m_eventingSuspended) {
                m_parent.OnNodeRemoved(node); 
            }
        }
        /// <summary>
        /// stop firing events from this node
        /// </summary>
        public void EventingSuspend() {
            m_eventingSuspended = true; 
        }
        /// <summary>
        /// resume firing events from this node
        /// </summary>
        public void EventingResume() {
            m_eventingSuspended = false; 
        }

        #endregion

        #region properties

        /// <summary>
        /// Get/set visiblility for the scene graph branch 
        /// </summary>
        public bool Visible {
            get { return m_visible; }
            set { m_visible = value; 
            }
        }
        /// <summary>
        /// reference to the scene graph node this node is a child of
        /// </summary>
        public ILSceneGraphNode Parent {
            get {
                return m_parent; 
            }
            set {
                m_parent = value; 
            }
        }
        /// <summary>
        /// the minimum coordinate of a cube tightly enclosing the node (and all childs) 
        /// </summary>
        /// <returns></returns>
        public virtual ILPoint3Df PositionMin {
            get {
                if (m_positionMin.IsEmtpy()) {
                    ComputeNodeLimits();
                }
                return m_positionMin;
            }
        }
        /// <summary>
        /// the maximum coordinate of a cube tightly enclosing the node (and all childs) 
        /// </summary>
        /// <returns></returns>
        public virtual ILPoint3Df PositionMax {
            get {
                if (m_positionMax.IsEmtpy()) {
                    ComputeNodeLimits();
                }
                return m_positionMax;
            }
        }
        /// <summary>
        /// current geometric center according of scene graph branch
        /// </summary>
        public virtual ILPoint3Df Center {
            get {
                if (m_center.IsEmtpy()) {
                    ComputeNodeLimits(); 
                }
                return m_center;
            }
        }
        #endregion

        #region public interface 
        /// <summary>
        /// invalidate geometry cache for this and all nodes up to root
        /// </summary>
        public virtual void Invalidate() {
            m_center = ILPoint3Df.Empty;
            m_positionMin = ILPoint3Df.Empty;
            m_positionMax = ILPoint3Df.Empty;
            m_invalidated = true;
            if (Parent != null) {
                Parent.Invalidate();
            } else {
                OnInvalidated();
            }
        }
        /// <summary>
        /// recompute the size spanned by this node, may fires Changed() event
        /// </summary>
        internal abstract void Configure(); 
        /// <summary>
        /// draw all children contained in this node
        /// </summary>
        /// <param name="props">extended rendering properties</param>
        internal abstract void Draw(ILRenderProperties props);

        #endregion

        #region private helper 
        /// <summary>
        /// compute limits of the cube tightly enclosing the branch below this node
        /// </summary>
        /// <returns></returns>
        protected abstract void ComputeNodeLimits(); 

        //protected void invalidateChilds(ILSceneGraphNode parent) {
        //    parent.m_center = ILPoint3Df.Empty;
        //    parent.m_positionMin = ILPoint3Df.Empty;
        //    parent.m_positionMax = ILPoint3Df.Empty;
        //    foreach (ILSceneGraphNode child in parent.m_childs) {
        //        child.invalidateChilds(child);
        //    }
        //}
        #endregion

        #region IEnumerable<ILSceneGraphNode> Member

        /// <summary>
        /// Create &amp; returns a typed enumerator
        /// </summary>
        /// <returns>enumerator of all scene graph nodes below this node</returns>
        public IEnumerator<ILSceneGraphNode> GetEnumerator() {
            List<ILSceneGraphNode> ret = new List<ILSceneGraphNode>();
            CollectAllChildren(ret);
            return ret.GetEnumerator(); 
        }
        #endregion

        #region IEnumerable Member
        /// <summary>
        /// Create and return untyped enumerator
        /// </summary>
        /// <returns>IEnumerator of all scene graph nodes below this node</returns>
        System.Collections.IEnumerator System.Collections.IEnumerable.GetEnumerator() {
            List<ILSceneGraphNode> children = new List<ILSceneGraphNode>();
            CollectAllChildren(children);
            foreach (ILSceneGraphNode node in children) {
                yield return node; 
            }
        }
        internal virtual void CollectAllChildren(List<ILSceneGraphNode> nodes) {
            nodes.Add(this); 
        }
        
        #endregion

    }

}