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using System;
using System.Collections;
using System.Collections.Generic;
using System.Text;

using Autodesk.Revit;
using Autodesk.Revit.DB;

namespace Revit.SDK.Samples.Reinforcement.CS
{
   using GeoInstance = Autodesk.Revit.DB.GeometryInstance;
   using Autodesk.Revit.DB.Structure;

   /// <summary>
   /// The base class which support beamGeometrySupport and ColumnGeometrySupport etc.
   /// it store some common geometry information, and give some helper fuctions
   /// </summary>
   public class GeometrySupport
   {
      /// <summary>
      /// store the solid of beam or column
      /// </summary>
      protected Solid m_solid;

      /// <summary>
      /// the extend or sweep path of the beam or column
      /// </summary>
      protected Line m_drivingLine;

      /// <summary>
      /// the director vector of beam or column
      /// </summary>
      protected Autodesk.Revit.DB.XYZ m_drivingVector;

      /// <summary>
      /// a list to store the edges 
      /// </summary>
      protected List<Line> m_edges = new List<Line>();

      /// <summary>
      /// a list to store the point
      /// </summary>
      protected List<Autodesk.Revit.DB.XYZ> m_points = new List<Autodesk.Revit.DB.XYZ>();

      /// <summary>
      /// the transform value of the solid
      /// </summary>
      protected Transform m_transform;

      /// <summary>
      /// constructor
      /// </summary>
      /// <param name="element">the host object, must be family instance</param>
      /// <param name="geoOptions">the geometry option</param>
      public GeometrySupport(FamilyInstance element, Options geoOptions)
      {
         // get the geometry element of the selected element
         Autodesk.Revit.DB.GeometryElement geoElement = element.get_Geometry(new Options());
         IEnumerator<GeometryObject> Objects = geoElement.GetEnumerator();
         if (null == geoElement || !Objects.MoveNext())
         {
            throw new Exception("Can't get the geometry of selected element.");
         }

         SweptProfile swProfile = element.GetSweptProfile();
         if (swProfile == null || !(swProfile.GetDrivingCurve() is Line))
         {
            throw new Exception("The selected element driving curve is not a line.");
         }

         // get the driving path and vector of the beam or column
         Line line = swProfile.GetDrivingCurve() as Line;
         if (null != line)
         {
            m_drivingLine = line;   // driving path
            m_drivingVector = GeomUtil.SubXYZ(line.GetEndPoint(1), line.GetEndPoint(0));
         }

         //get the geometry object
         Objects.Reset();
         //foreach (GeometryObject geoObject in geoElement.Objects)
         while (Objects.MoveNext())
         {
            GeometryObject geoObject = Objects.Current;

            //get the geometry instance which contain the geometry information
            GeoInstance instance = geoObject as GeoInstance;
            if (null != instance)
            {
               //foreach (GeometryObject o in instance.SymbolGeometry.Objects)
               IEnumerator<GeometryObject> Objects1 = instance.SymbolGeometry.GetEnumerator();
               while (Objects1.MoveNext())
               {
                  GeometryObject o = Objects1.Current;

                  // get the solid of beam of column
                  Solid solid = o as Solid;

                  // do some checks.
                  if (null == solid)
                  {
                     continue;
                  }
                  if (0 == solid.Faces.Size || 0 == solid.Edges.Size)
                  {
                     continue;
                  }

                  m_solid = solid;
                  //get the transform value of instance
                  m_transform = instance.Transform;

                  // Get the swept profile curves information
                  if (!GetSweptProfile(solid))
                  {
                     throw new Exception("Can't get the swept profile curves.");
                  }
                  break;
               }
            }

         }

         // do some checks about profile curves information
         if (null == m_edges)
         {
            throw new Exception("Can't get the geometry edge information.");
         }
         if (4 != m_points.Count)
         {
            throw new Exception("The sample only work for rectangular beams or columns.");
         }
      }


      /// <summary>
      /// transform the point to new coordinates
      /// </summary>
      /// <param name="point">the point need to transform</param>
      /// <returns>the changed point</returns>
      protected Autodesk.Revit.DB.XYZ Transform(Autodesk.Revit.DB.XYZ point)
      {
         // only invoke the TransformPoint() method.
         return GeomUtil.TransformPoint(point, m_transform);
      }


      /// <summary>
      /// Get the length of driving line
      /// </summary>
      /// <returns>the length of the driving line</returns>
      protected double GetDrivingLineLength()
      {
         return GeomUtil.GetLength(m_drivingVector);
      }

      /// <summary>
      /// Get two vectors, which indicate some edge direction which contain given point, 
      /// set the given point as the start point, the other end point of the edge as end
      /// </summary>
      /// <param name="point">a point of the swept profile</param>
      /// <returns>two vectors indicate edge direction</returns>
      protected List<Autodesk.Revit.DB.XYZ> GetRelatedVectors(Autodesk.Revit.DB.XYZ point)
      {
         // Initialize the return vector list.
         List<Autodesk.Revit.DB.XYZ> vectors = new List<Autodesk.Revit.DB.XYZ>();

         // Get all the edge which contain this point.
         // And get the vector from this point to another point
         foreach (Line line in m_edges)
         {
            if (GeomUtil.IsEqual(point, line.GetEndPoint(0)))
            {
               Autodesk.Revit.DB.XYZ vector = GeomUtil.SubXYZ(line.GetEndPoint(1), line.GetEndPoint(0));
               vectors.Add(vector);
            }
            if (GeomUtil.IsEqual(point, line.GetEndPoint(1)))
            {
               Autodesk.Revit.DB.XYZ vector = GeomUtil.SubXYZ(line.GetEndPoint(0), line.GetEndPoint(1));
               vectors.Add(vector);
            }
         }

         // only two vector(direction) should be found
         if (2 != vectors.Count)
         {
            throw new Exception("a point on swept profile should have only two direction.");
         }

         return vectors;
      }


      /// <summary>
      /// Offset the points of the swept profile to make the points inside swept profile
      /// </summary>
      /// <param name="offset">indicate how long to offset on two directions</param>
      /// <returns>the offset points</returns>
      protected List<Autodesk.Revit.DB.XYZ> OffsetPoints(double offset)
      {
         // Initialize the offset point list.
         List<Autodesk.Revit.DB.XYZ> points = new List<Autodesk.Revit.DB.XYZ>();

         // Get all points of the swept profile, and offset it in two related direction
         foreach (Autodesk.Revit.DB.XYZ point in m_points)
         {
            // Get two related directions
            List<Autodesk.Revit.DB.XYZ> directions = GetRelatedVectors(point);
            Autodesk.Revit.DB.XYZ firstDir = directions[0];
            Autodesk.Revit.DB.XYZ secondDir = directions[1];

            // offset the point in two direction
            Autodesk.Revit.DB.XYZ movedPoint = GeomUtil.OffsetPoint(point, firstDir, offset);
            movedPoint = GeomUtil.OffsetPoint(movedPoint, secondDir, offset);

            // add the offset point into the array
            points.Add(movedPoint);
         }

         return points;
      }


      /// <summary>
      /// Find the inforamtion of the swept profile(face), 
      /// and store the points and edges of the profile(face) 
      /// </summary>
      /// <param name="solid">the solid reference</param>
      /// <returns>true if the swept profile can be gotten, otherwise false</returns>
      private bool GetSweptProfile(Solid solid)
      {
         // get the swept face
         Face sweptFace = GetSweptProfileFace(solid);
         // do some checks
         if (null == sweptFace || 1 != sweptFace.EdgeLoops.Size)
         {
            return false;
         }

         // get the points of the swept face
         foreach (Autodesk.Revit.DB.XYZ point in sweptFace.Triangulate().Vertices)
         {
            m_points.Add(Transform(point));
         }

         // get the edges of the swept face
         m_edges = ChangeEdgeToLine(sweptFace.EdgeLoops.get_Item(0));

         // do some checks
         return (null != m_edges);
      }

      /// <summary>
      /// Get the swept profile(face) of the host object(family instance)
      /// </summary>
      /// <param name="solid">the solid reference</param>
      /// <returns>the swept profile</returns>
      private Face GetSweptProfileFace(Solid solid)
      {
         // Get a point on the swept profile from all points in solid
         Autodesk.Revit.DB.XYZ refPoint = new Autodesk.Revit.DB.XYZ();   // the point on swept profile
         foreach (Edge edge in solid.Edges)
         {
            List<XYZ> points = edge.Tessellate() as List<XYZ>;    //get end points of the edge
            if (2 != points.Count)                   // make sure all edges are lines
            {
               throw new Exception("All edge should be line.");
            }

            // get two points of the edge. All points in solid should be transform first
            Autodesk.Revit.DB.XYZ first = Transform(points[0]);  // start point of edge
            Autodesk.Revit.DB.XYZ second = Transform(points[1]); // end point of edge

            // some edges should be parallelled with the driving line,
            // and the start point of that edge should be the wanted point
            Autodesk.Revit.DB.XYZ edgeVector = GeomUtil.SubXYZ(second, first);
            if (GeomUtil.IsSameDirection(edgeVector, m_drivingVector))
            {
               refPoint = first;
               break;
            }
            if (GeomUtil.IsOppositeDirection(edgeVector, m_drivingVector))
            {
               refPoint = second;
               break;
            }
         }

         // Find swept profile(face)
         Face sweptFace = null;  // define the swept face
         foreach (Face face in solid.Faces)
         {
            if (null != sweptFace)
            {
               break;
            }
            // the swept face should be perpendicular with the driving line
            if (!GeomUtil.IsVertical(face, m_drivingLine, m_transform, null))
            {
               continue;
            }
            // use the gotted point to get the swept face
            foreach (Autodesk.Revit.DB.XYZ point in face.Triangulate().Vertices)
            {
               Autodesk.Revit.DB.XYZ pnt = Transform(point); // all points in solid should be transform
               if (GeomUtil.IsEqual(refPoint, pnt))
               {
                  sweptFace = face;
                  break;
               }
            }
         }

         return sweptFace;
      }

      /// <summary>
      /// Change the swept profile edges from EdgeArray type to line list
      /// </summary>
      /// <param name="edges">the swept profile edges</param>
      /// <returns>the line list which stores the swept profile edges</returns>
      private List<Line> ChangeEdgeToLine(EdgeArray edges)
      {
         // create the line list instance.
         List<Line> edgeLines = new List<Line>();

         // get each edge from swept profile,
         // and changed the geometry information in line list
         foreach (Edge edge in edges)
         {
            //get the two points of each edge
            List<XYZ> points = edge.Tessellate() as List<XYZ>;
            Autodesk.Revit.DB.XYZ first = Transform(points[0]);
            Autodesk.Revit.DB.XYZ second = Transform(points[1]);

            // create new line and add them into line list
            edgeLines.Add(Line.CreateBound(first, second));
         }

         return edgeLines;
      }
   }
}