node = hou.pwd ( )
geo = node.geometry ( )

def filterEdgeGroup ( edgeGroup ):
    group = []
    names = edgeGroup.split ( ' ' )
    for name in names:
        try:
            edges = geo.globEdges ( name )
        except hou.OperationFailed:
            edges = ( )
        
        for edge in edges:
            p0 = edge.points ( ) [ 0 ]
            p1 = edge.points ( ) [ 1 ]
            
            try:
                isValidEdge = geo.findEdge ( p0, p1 )
            except:
                isValidEdge = False
            
            if not isValidEdge:
                continue
            
            if len ( edge.prims ( ) ):
                group.append ( edge )
    
    return group


def getPolysFromEdges ( edges ):
    polys = []
    for edge in edges:
        polys += edge.prims ( )
    
    return polys


def getPointsFromEdges ( edges ):
    points = set ( )
    for edge in edges:
        points.add ( edge.points ( ) [ 0 ] )
        points.add ( edge.points ( ) [ 1 ] )
    
    return points


def getPointsFromPolys ( polys ):
    points = set ( )
    for poly in polys:
        verts = poly.vertices ( )
        for vert in verts:
            points.add ( vert.point ( ) )
    
    return points


def isValidEdge ( point1, point2 ):
    try:
        group = geo.globEdges ( "p{0}-{1} ".format ( point1, point2 ) )
    except hou.OperationFailed:
        return False
    
    for edge in group:
        p0 = edge.points ( ) [ 0 ]
        p1 = edge.points ( ) [ 1 ]
        
        try:
            return geo.findEdge ( p0, p1 ) != None
        except:
            return False


def getEdgePointsOfPoint ( point ):
    points = hou.hscriptExpression ( "pointneighbours(\"" + node.inputs ( ) [ 0 ].path ( ) + "\", " + str ( point ) + ", 1)" )
    points = points.split ( ' ' )
    points = map ( int, points )
    edgePoints = set ( )
    for pt in points:
        if isValidEdge ( point, pt ):
            edgePoints.add ( geo.iterPoints ( ) [ pt ] )
    
    return edgePoints



group = hou.evalParm ( "group" )
amount = hou.evalParm ( "amount" )
edges = filterEdgeGroup ( group )

if not edges:
    raise hou.NodeWarning ( "No valid edges were found in the group." )

polys = getPolysFromEdges ( edges )
points = getPointsFromEdges ( edges )
outerPoints = getPointsFromPolys ( polys )
outerPoints -= points

if not outerPoints:
    raise hou.NodeWarning ( "No valid edges were found in the group." )

first = outerPoints.pop ( )
source = { first }
innerPoints = { first }

while source:
    edgePoints = getEdgePointsOfPoint ( source.pop ( ).number ( ) )
    shared = edgePoints.intersection ( outerPoints )
    source = source.union ( shared )
    innerPoints = innerPoints.union ( shared )
    outerPoints = outerPoints.difference ( edgePoints )

goals = outerPoints
if ( amount < 0 ):
    goals = innerPoints

for point in points:
    edgePoints = getEdgePointsOfPoint ( point.number ( ) )
    target = edgePoints.intersection ( goals )
    if target:
        p0 = target.pop ( ).position ( )
        p1 = point.position ( )
        point.setPosition ( p1 + ( p0 - p1 ) * abs ( amount ) )