try:
    del App.Flatpack
except:
    pass

ad = Gui.ActiveDocument.Document

def selectionContainsAssembly():
    sel = Gui.Selection.getSelection()

    if not sel or not hasattr(sel[0], 'Type') or sel[0].Type != 'Assembly':
        return False

    return sel[0]

class FlatpackGroupViewProvider():
    def __init__(self, group):
        self.Proxy = group

class FlatpackWBTools():
    def createDatumPlaneOnLink(self, part, link):
        plane = part.newObject('PartDesign::Plane', 'DatumPlane')

        return plane

    def createGroup(self, asm):
        pack = ad.addObject('App::Part', 'Flatpack')
        pack.Type = 'Flatpack'

        FlatpackGroupViewProvider(pack)

        #asm.Visibility = False

        self.links = self.findLinks(asm)

        for link in self.links:
            attached_to = ad.getObject(link.AttachedTo.split('#')[1])
            
            # not much to do when attached to the root
            if attached_to.Name == 'LCS_Origin':
                print('Skipping LCS_Origin')
                continue

            print(link.Name, link.Placement)

            # find all the App::Links that are on the same Plane as this one
            coplaner_links = []
            for i in [ l for l in link.OutList if l.TypeId == 'PartDesign::CoordinateSystem' ]:
                if l not in coplaner_links and abs(link.Placement.Base.z - l.Placement.Base.z) < 0.000001:
                    print(link.Label, l.Label, abs(link.Placement.Base.z- l.Placement.Base.z), link.Placement.Base.z==l.Placement.Base.z)
                    coplaner_links.append(l)

            print('coplaner_links', coplaner_links)
            for cp_link in coplaner_links:
                base = cp_link.Placement.Base

                # create DatumPlane for Sketch Support
                # TODO track planes per Z offset
                plane = self.createDatumPlaneOnLink(link.LinkedObject, link)
                plane.Visibility = False
                plane.Placement.Base.z = base.z

                # create Sketch for drawing attachment features
                sketch = self.createSketch(link.LinkedObject, plane)
                sketch.Visibility = False

                # TODO needs input parameters from 1) the Flatpack object 2) the depth of the LinkedObject
                sketch.addGeometry(Part.LineSegment(App.Vector(base.x-10, base.y, 0), App.Vector(base.x+10, base.y, 0)), False)
                sketch.addGeometry(Part.LineSegment(App.Vector(base.x+10, base.y, 0), App.Vector(base.x+10, base.y + 5, 0)), False)
                sketch.addGeometry(Part.LineSegment(App.Vector(base.x+10, base.y + 5, 0), App.Vector(base.x-10, base.y + 5, 0)), False)
                sketch.addGeometry(Part.LineSegment(App.Vector(base.x-10, base.y + 5, 0), App.Vector(base.x-10, base.y, 0)), False)
                
                # TODO determine if Feature should be Pad or Pocket, based on inside/outside of BoundingBox
                pad = link.LinkedObject.newObject('PartDesign::Pad', 'Pad')
                pad.Profile = sketch
                # TODO get value from elsewhere
                pad.Length = 10
                pad.Midplane = 1
                pad.Refine = 1

    def createSketch(self, part, attached_to):
        sketch = part.newObject('Sketcher::SketchObject', 'Sketch')

        # determine face orientation....

        sketch.Support = (attached_to, ['Face001'])
        sketch.MapMode = 'FlatFace'

        return sketch

    def findAssembly(self):
        sel = selectionContainsAssembly()

        if not sel:
            return False

        return sel

    def findLinks(self, asm, discard_origin = False):
        return [] if not asm else [el for el in asm.OutList if el.TypeId == 'App::Link']

    def getLinkOwner(self, link):
        return link.LinkedObject

FP = App.Flatpack = FlatpackWBTools()
asm = Gui.ActiveDocument.Document.getObject('Model')

asm = FP.findAssembly()

if asm:
    FP.createGroup(asm)
else:
    print('No Assembly selected.')

ad.recompute()