import FreeCAD as App
import FreeCADGui as Gui
import Part

# ============================================================
# CONFIG
# ============================================================

TARGET_X = 75.0
TARGET_Y = 75.0
TARGET_Z = 50.0

LAYER_THICKNESS = 2.5  # mm (card/MDF range)

DEBUG_STEP_VISUALS = True

# ============================================================
# LOG
# ============================================================

def log(msg):
    App.Console.PrintMessage(str(msg) + "\n")

# ============================================================
# GET OBJECT
# ============================================================

sel = Gui.Selection.getSelection()

if len(sel) == 0:
    raise Exception("Select a single solid first")

obj = sel[0]

if not hasattr(obj, "Shape"):
    raise Exception("Selected object has no Shape")

shape = obj.Shape.copy()

log("Selected: " + obj.Name)

# ============================================================
# SCALE TO FIT BBOX
# ============================================================

bb = shape.BoundBox

sx = TARGET_X / bb.XLength
sy = TARGET_Y / bb.YLength
sz = TARGET_Z / bb.ZLength

scale = min(sx, sy, sz)

log("Scale factor: " + str(scale))

m = App.Matrix()
m.scale(scale, scale, scale)

shape = shape.transformGeometry(m)

bb = shape.BoundBox

log("Scaled bbox:")
log(str(bb.XLength) + " x " + str(bb.YLength) + " x " + str(bb.ZLength))

# ============================================================
# CREATE OUTPUT DOC
# ============================================================

doc = App.newDocument("SLICES_OUTPUT")

# optional: copy scaled model for reference
ref = doc.addObject("Part::Feature", "ScaledModel")
ref.Shape = shape

# ============================================================
# SLICING LOOP
# ============================================================

z = bb.ZMin
index = 0

while z <= bb.ZMax:

    log("Slice " + str(index) + " at Z=" + str(z))

    # large plane for intersection
    plane = Part.makePlane(
        bb.XLength * 3,
        bb.YLength * 3,
        App.Vector(bb.XMin - bb.XLength, bb.YMin - bb.YLength, z)
    )

    section = shape.section(plane)

    # IMPORTANT: section can be compound
    if section.isNull() or len(section.Edges) == 0:
        log("  empty slice")
        z += LAYER_THICKNESS
        index += 1
        continue

    # store slice
    slice_obj = doc.addObject("Part::Feature", f"Slice_{index:03d}")
    slice_obj.Shape = section

    # visually offset slices in X so you can inspect them
    if DEBUG_STEP_VISUALS:
        slice_obj.Placement.Base = App.Vector(index * 5, 0, 0)

    log("  edges: " + str(len(section.Edges)))

    z += LAYER_THICKNESS
    index += 1

# ============================================================
# FINALIZE
# ============================================================

doc.recompute()

Gui.ActiveDocument.ActiveView.fitAll()

log("DONE - generated " + str(index) + " slices")