"""Spearfish: the moving parts through their travel against the static exterior (exec'd in Blender, or headless with
blender -b Tender_Spearfish.blend --python build/motion_check.py). Writes checks/motion.json; leaves the rig as found.
  * top hatch: 0 .. 100 deg in 2 deg steps, intersections with the hull and least gap;
  * whip masts: 0 .. 1 folded in 0.05 steps, intersections with the hull and least gap."""
import bpy, os, json
from mathutils import Vector
from mathutils.bvhtree import BVHTree
HERE = r"D:\HADAL - The Descent\models\tender-spearfish\build"
root = bpy.data.objects["Spearfish_Root"]
for ob in bpy.data.objects:
    if ob.animation_data:
        for fc in ob.animation_data.drivers:
            fc.driver.expression = fc.driver.expression
            fc.driver.is_valid = True


def world_tree(o):
    dg = bpy.context.evaluated_depsgraph_get()
    ev = o.evaluated_get(dg)
    me = ev.to_mesh()
    M = ev.matrix_world
    vs = [M @ v.co for v in me.vertices]
    ps = [tuple(p.vertices) for p in me.polygons]
    ev.to_mesh_clear()
    return BVHTree.FromPolygons(vs, ps), vs


hull_t, hull_v = world_tree(bpy.data.objects["SM_Spearfish_Hull"])


def probe(o, pivot=None, skip_r=0.0):
    """intersections and least gap; faces within skip_r of the pivot (a mast in its socket, a lid on its hinge) left out"""
    dg = bpy.context.evaluated_depsgraph_get()
    ev = o.evaluated_get(dg)
    me = ev.to_mesh()
    M = ev.matrix_world
    vs = [M @ v.co for v in me.vertices]
    pv = (M @ Vector(pivot)) if pivot is not None else None
    ps = [tuple(p.vertices) for p in me.polygons
          if pv is None or min((vs[i] - pv).length for i in p.vertices) > skip_r]
    ev.to_mesh_clear()
    used = sorted({i for p in ps for i in p})
    t = BVHTree.FromPolygons(vs, ps)
    vs = [vs[i] for i in used]
    hits = len(t.overlap(hull_t))
    gap = min(hull_t.find_nearest(p)[3] for p in vs[::3])
    return hits, round(gap, 4)


keep = (root["masts_folded"], root["hatch_open_deg"])
out = {"hatch": [], "masts": []}
for deg in range(0, 101, 2):
    root["hatch_open_deg"] = float(deg); root.update_tag(); bpy.context.view_layer.update()
    h, g = probe(bpy.data.objects["SM_Spearfish_Hatch"])          # the lid sits 14 mm proud; its hinge is its aft edge
    out["hatch"].append([deg, h, g])
root["hatch_open_deg"] = 0.0
for j in range(21):
    root["masts_folded"] = j / 20; root.update_tag(); bpy.context.view_layer.update()
    row = [j / 20]
    for nm in ("SM_Spearfish_Mast_L", "SM_Spearfish_Mast_R"):
        row += list(probe(bpy.data.objects[nm], pivot=(0, 0, 0), skip_r=0.075))   # the whip's foot turns in its socket
    out["masts"].append(row)
root["masts_folded"], root["hatch_open_deg"] = keep
root.update_tag(); bpy.context.view_layer.update()
summary = {"hatch_hits": sum(r[1] for r in out["hatch"]), "hatch_least_gap_m": min(r[2] for r in out["hatch"][1:]),
           "hatch_hits_shut": out["hatch"][0][1],
           "mast_hits": sum(r[1] + r[3] for r in out["masts"]), "mast_least_gap_m": min(min(r[2], r[4]) for r in out["masts"])}
out["summary"] = summary
json.dump(out, open(os.path.join(HERE, "checks", "motion.json"), "w"), indent=1)
print("MOTION", json.dumps(summary))
result = summary