# find and store LINE, ARC, CIRCLE entities into a list of dicts
'''
Line group codes
Group codes 	Description

100 Subclass marker (AcDbLine)
39 Thickness (optional; default = 0)
10 Start point (in WCS). DXF: X value; APP: 3D point
20, 30 DXF: Y and Z values of start point (in WCS)
11 End point (in WCS). DXF: X value; APP: 3D point
21, 31 DXF: Y and Z values of end point (in WCS)
210 Extrusion direction. (optional; default = 0, 0, 1). DXF: X value; APP: 3D vector
220, 230 DXF: Y and Z values of extrusion direction

Arc group codes
Group codes 	Description
100 Subclass marker (AcDbCircle)
39 Thickness (optional; default = 0)
10 Center point (in OCS). DXF: X value; APP: 3D point
20, 30 DXF: Y and Z values of center point (in OCS)
40 Radius
100 Subclass marker (AcDbArc)
50 Start angle
51 End angle
210 Extrusion direction. (optional; default = 0, 0, 1). DXF: X value; APP: 3D vector
220, 230 DXF: Y and Z values of extrusion direction

Circle group codes
Group codes 	Description

100 Subclass marker (AcDbCircle)
39 Thickness (optional; default = 0)
10 Center point (in OCS). DXF: X value; APP: 3D point
20, 30 DXF: Y and Z values of center point (in OCS)
40 Radius
210 Extrusion direction. (optional; default = 0, 0, 1). DXF: X value; APP: 3D vector
220, 230 DXF: Y and Z values of extrusion direction
'''

def readdxf(fn):
  startEntities = False
  startLine = False
  startArc = False
  startCircle = False
  storePoint = False
  entities = []

  with open(fn, 'r') as f:
    for line in f:
      if line.strip() == 'ENTITIES':
        startEntities = True

      if startEntities:
        if line.strip() == 'LINE':
          dd = dict.fromkeys(('10','20','30','11','21','31'), 0.0)
          dd['type'] = line.strip()
          startLine = True

        if line.strip() == 'ARC':
          dd = dict.fromkeys(('10','20','30','40','50','51'), 0.0)
          dd['type'] = line.strip()
          startArc = True

        if line.strip() == 'CIRCLE':
          dd = dict.fromkeys(('10','20','30','11','21','31'), 0.0)
          dd['type'] = line.strip()
          startCircle = True

        if line.strip() == 'ENDSEC':
          startEntities = False

      if startLine:
        if storePoint:
          dd[entity] = line.strip()
          storePoint = False

        if line.strip() in dd:
          entity = line.strip()
          storePoint = True

        if line == '  0\r\n':
          startLine = False
          entities.append(dd)

      if startArc:
        if storePoint:
          dd[entity] = line.strip()
          storePoint = False

        if line.strip() in dd:
          entity = line.strip()
          storePoint = True

        if line == '  0\r\n':
          startArc = False
          entities.append(dd)

      if startCircle:
        if storePoint:
          dd[entity] = line.strip()
          storePoint = False

        if line.strip() in dd:
          entity = line.strip()
          storePoint = True

        if line == '  0\r\n':
          startCircle = False
          entities.append(dd)

  return entities