"""Pergola with string lights, over the bench at Tidewater. Writes pergola.json for bridge/slbuild.py.
Root = the SW post; everything else is relative to it (no rotation on the root). Claude Opus 5.5, 2026-10-10."""
import json
import math

W, D, H = 3.4, 2.3, 2.6          # x span between post centres, y span, post height
POST, BEAM = 0.12, 0.1
WOOD, DARK = "#8a5f38", "#5a3f28"
BULB = "#ffd9a0"
prims = []


def add(**p):
    p.setdefault("texture", "blank")
    prims.append(p)


# posts: root at local (0,0,0) is the SW post's centre; build bottom rests on the ground
corners = [(0, 0), (W, 0), (0, D), (W, D)]
for i, (x, y) in enumerate(corners):
    add(name="Tidewater Pergola" if i == 0 else "post", shape="box", size=[POST, POST, H],
        **({} if i == 0 else {"pos": [x, y, 0]}), color=DARK, bump="wood")
top = H / 2
# beams along x on both long sides, a little proud of the posts
for y in (0, D):
    add(name="beam", shape="box", size=[W + 0.5, BEAM, 0.16], pos=[W / 2, y, top + 0.04], color=WOOD, bump="wood")
# rafters across, resting on the beams
for k in range(6):
    x = -0.1 + k * (W + 0.2) / 5
    add(name="rafter", shape="box", size=[0.07, D + 0.5, 0.12], pos=[round(x, 3), D / 2, top + 0.17], color=WOOD, bump="wood")

# string lights: a sagging strand under each beam, bulbs at even steps, wire segments between them
n, sag = 8, 0.28
for side, y in (("n", D - 0.04), ("s", 0.04)):
    pts = []
    for k in range(n):
        t = k / (n - 1)
        x = 0.08 + t * (W - 0.16)
        z = top - 0.12 - sag * 4 * t * (1 - t)
        pts.append((x, z))
    for k, (x, z) in enumerate(pts):
        bulb = dict(name="bulb", shape="sphere", size=[0.07, 0.07, 0.09], pos=[round(x, 3), y, round(z - 0.05, 3)],
                    color=BULB, fullbright=True, glow=0.3)
        if side == "n" and k == n // 2:
            bulb["light"] = {"color": "#ffcf8a", "intensity": 0.8, "radius": 6, "falloff": 0.8}
        add(**bulb)
    for (x1, z1), (x2, z2) in zip(pts, pts[1:]):
        length = math.hypot(x2 - x1, z2 - z1)
        tilt = math.degrees(math.atan2(x2 - x1, z2 - z1))  # cylinder axis (+z) turned about y onto the segment
        add(name="wire", shape="cylinder", size=[0.012, 0.012, round(length, 3)],
            pos=[round((x1 + x2) / 2, 3), y, round((z1 + z2) / 2, 3)], rot=[0, round(tilt, 2), 0], color="#1a1a1a")

with open("pergola.json", "w") as f:
    f.write("// generated by gen_pergola.py\n{\n  \"name\": \"Tidewater Pergola\",\n  \"desc\": \"Made by Tessel the AI (Claude)\",\n  \"prims\": [\n")
    f.write(",\n".join("    " + json.dumps(p) for p in prims))
    f.write("\n  ]\n}\n")
print(len(prims), "prims")