"""19-inch rack panel: a flat aluminium blank panel, 1U to 4U, with four open mounting slots at its ends, from Hammond Manufacturing's
PBPA series drawings (EIA-310 rack). The panel lies on the XY plane, its back face down and its front face up (+Z): its width along X,
centred on the origin, and its height along Y, the bottom edge on the X axis. Dimensions are in the README."""
from steve import Model

units = "1U"  # Rack units (panel height)
finish = "black"  # Finish

INCH = 25.4
# Each entry: (Hammond part number, panel height, first slot below the top edge, slot spacing), inches.
#   Hammond Manufacturing dimensional drawings PBPA19001, PBPA19003, PBPA19005 and PBPA19007 (no revision shown), front view, copies
#   hosted by AutomationDirect at cdn.automationdirect.com/static/drawings/PBPA19001BK.pdf (and ...19003BK, 19005BK, 19007BK):
#   1U 1.72 high, slots .23 below the top and 1.25 apart; 2U 3.47, .23, 3.00; 3U 5.22, 1.48, 2.25; 4U 6.97, 1.48, 4.00.
UNITS = {
    "1U": ("PBPA19001", 1.72, 0.23, 1.25),
    "2U": ("PBPA19003", 3.47, 0.23, 3.00),
    "3U": ("PBPA19005", 5.22, 1.48, 2.25),
    "4U": ("PBPA19007", 6.97, 1.48, 4.00),
}
# The same drawings, every size: width 19.00, slot centres 18.19 apart, 4X 0.250 x 0.531 slot (open at the end edge, 0.531 deep, a
# 0.250 wide slot with a round end), material 0.125" aluminium (notes), inches.
WIDTH = 19.00
SLOT_CENTRES = 18.19
SLOT_WIDTH = 0.250
SLOT_DEPTH = 0.531
THICKNESS = 0.125
# Finish: the drawings' part-number suffixes (BK2 painted black, CG2 RAL 7032 grey, GY2 ASA 61 grey, LG2 RAL 7035 grey, UNF unfinished);
# AutomationDirect's PBPA19001BK cut sheet names the alloy 5052-H32. Colours are for looks only.
FINISHES = {
    "black": ("BK2", "#1d1e20"),
    "ral7032-gray": ("CG2", "#b5b39a"),
    "asa61-gray": ("GY2", "#8e9294"),
    "ral7035-gray": ("LG2", "#c8cac7"),
    "unfinished": ("UNF", "#d4d7db"),
}

if units not in UNITS:
    raise ValueError(f"no size {units!r}: {', '.join(UNITS)}")
if finish not in FINISHES:
    raise ValueError(f"no finish {finish!r}: {', '.join(FINISHES)}")
_, height_in, first_in, pitch_in = UNITS[units]
W, H, t = WIDTH * INCH, height_in * INCH, THICKNESS * INCH
r = SLOT_WIDTH * INCH / 2
# The slot's round end: its centre is SLOT_DEPTH - radius in from the end edge, which puts the left and right centres
# 19.00 - 2 x 0.406 = 18.19 apart, the drawing's centre distance.
inset = SLOT_DEPTH * INCH - r
slot_y = [H - first_in * INCH, H - (first_in + pitch_in) * INCH]

model = Model()
with model.sketch("panel_sketch", on="XY", name="Panel") as sk:
    sk.rect("panel_rect", (-W / 2, 0), (W / 2, H))
model.extrude("panel", "panel_sketch", distance=t, op="new", body="panel_body", name="Panel")
# The slots, cut in two steps (the straight part from the end edge, then the round end) so that no sketch has overlapping shapes.
with model.sketch("slot_sketch", on="XY", name="Mounting slots") as sk:
    for i, y in enumerate(slot_y):
        for side, sx in (("left", -1), ("right", 1)):
            x_edge, x_centre = sx * (W / 2 + 1), sx * (W / 2 - inset)
            sk.rect(f"slot_{side}_{i}_rect", (min(x_edge, x_centre), y - r), (max(x_edge, x_centre), y + r))
model.extrude("slots", "slot_sketch", distance=t, op="cut", body="panel_body", name="Mounting slots")
with model.sketch("slot_end_sketch", on="XY", name="Slot ends") as sk:
    for i, y in enumerate(slot_y):
        for side, sx in (("left", -1), ("right", 1)):
            sk.circle(f"slot_{side}_{i}_end", (sx * (W / 2 - inset), y), r)
model.extrude("slot_ends", "slot_end_sketch", distance=t, op="cut", body="panel_body", name="Slot ends")
# Material: 5052-H32 aluminium (the cut sheet), painted in the chosen finish.
model.material("aluminum-5052-h32", bodies=["panel_body"], color=FINISHES[finish][1])
result = model.result()