"""Parallel key, form A (both ends rounded), DIN 6885-1: width b, height h, overall length l. Centred on the origin: length
along X, width along Y, base on the XY plane."""
from steve import Model

size = "5x5"  # Key width x height
length = 20  # mm Key length

# b x h: (width b, height h). DIN 6885-1:1968, table of key sizes, as listed at
# https://fasten.it/en/norms/norm/din_6885-1 (shaft ranges there too).
KEYS = {"2x2": (2, 2), "3x3": (3, 3), "4x4": (4, 4), "5x5": (5, 5), "6x6": (6, 6), "8x7": (8, 7), "10x8": (10, 8), "12x8": (12, 8)}

b, h = KEYS[size]
if length <= b:
    raise ValueError(f"A {size} key is longer than its {b} mm width.")

model = Model()
with model.sketch("outline", on="XY", name="Key") as sk:
    sk.slot("key", (-(length - b) / 2, 0), ((length - b) / 2, 0), b / 2)
model.extrude("key", "outline", distance=h, name="Key")
model.material("steel-generic", color="#a7abb0")
result = model.result()