"""Corner bracket for 20, 30 and 40 mm aluminium extrusions, simplified as step.parts' published models draw it: two
flat legs at a right angle, no holes.

The legs stand on the XY plane and rise along +Z by the bracket's height (the extrusion size). One leg runs along +X,
the other along +Y, each `t` thick and centred on its axis, `leg` long from the origin; the small square at the
outside of the corner (-t/2..0, -t/2..0) is open, as in the models.
"""
from steve import Model

series = "2020"  # Extrusion series
variant = "single"  # Leg length: single or double
material = "unspecified"  # Material

# mm, measured on step.parts' models corner_bracket_<series>_<variant>_simple (their outline, a polygon read edge by
# edge at mid-height, and their height): {series: (height, thickness t, {variant: leg length})}
BRACKETS = {
    "2020": (20.0, 3.0, {"single": 30.0, "double": 40.0}),
    "3030": (30.0, 4.5, {"single": 45.0, "double": 60.0}),
    "4040": (40.0, 6.0, {"single": 60.0, "double": 80.0}),
}
MATERIALS = {
    "unspecified": (None, None),       # the models name no material
    "aluminum": ("aluminum-generic", "#cfd2d6"),
    "steel": ("steel-generic", "#7d8085"),
}

height, t, legs = BRACKETS[series]
leg = legs[variant]
h = t / 2
material_id, colour = MATERIALS[material]

model = Model()
with model.sketch("outline_sketch", on="XY", name="Outline") as sk:
    sk.polyline("outline", [(0, 0), (0, -h), (leg, -h), (leg, h), (h, h), (h, leg), (-h, leg), (-h, 0)])
model.extrude("bracket", "outline_sketch", distance=height, name="Bracket")
if material_id:
    model.material(material_id, color=colour)
result = model.result()