"""Dashpot / gas strut envelope: a cylinder body and a piston rod as two bodies, as step.parts' published models draw
them, any stroke.

The body (diameter BODY_D, length 30 + stroke) lies along +X from the origin; the rod (diameter ROD_D, length
50 + stroke) runs inside it on the same axis and comes out at +X, 10 + stroke / 2 beyond the body. The rod starts
stroke / 2 - 10 from the body's left end (for strokes under 20 mm it shows behind the body, as in the models). End
fittings, the piston and the seals are not modelled.
"""
from steve import Model

stroke = 50  # mm Stroke
material = "unspecified"  # Material

# mm, measured on step.parts' models dashpot_stroke<s>_envelope and gas_strut_stroke<s>_envelope (s = 10, 15, 25, 50,
# 100; the cylinders of their two solids): body and rod diameters, and lengths that grow with the stroke as below
BODY_D = 10.0
ROD_D = 5.0
BODY_BASE = 30.0      # body length = BODY_BASE + stroke
ROD_BASE = 50.0       # rod length = ROD_BASE + stroke
ROD_OUT_BASE = 10.0   # rod end beyond the body = ROD_OUT_BASE + stroke / 2
MATERIALS = {"unspecified": (None, None), "steel": ("steel-generic", "#9da2a8")}

body_length = BODY_BASE + stroke
rod_length = ROD_BASE + stroke
rod_end = body_length + ROD_OUT_BASE + stroke / 2
material_id, colour = MATERIALS[material]

model = Model()
model.cylinder("body", BODY_D / 2, body_length, direction=(1, 0, 0), name="Body")
model.cylinder("rod", ROD_D / 2, rod_length, at=(rod_end - rod_length, 0, 0), direction=(1, 0, 0), op="new",
               name="Rod")
if material_id:
    model.material(material_id, color=colour)
result = model.result()