"""Check the station: the driver, the canister through its whole slide, topology. Nothing is saved.

    blender.exe -b ../CanisterStation.blend --python cs_check.py      -> build/check_report.json

Runs CanisterStation_Root["eject"] from 0 to 1 in 101 steps and tests the canister against the body (triangle overlap
in world space, BVH), and measures its smallest clearance to the body (vertices of the canister to the body's surface).
"""
import bpy, bmesh, json, os, math
from mathutils.bvhtree import BVHTree

HERE = os.path.dirname(os.path.abspath(__file__))
exec(open(os.path.join(HERE, "cs_lib.py")).read())


def bvh(ob, dg):
    ev = ob.evaluated_get(dg)
    me = ev.to_mesh()
    bm = bmesh.new()
    bm.from_mesh(me)
    bm.transform(ev.matrix_world)
    t = BVHTree.FromBMesh(bm)
    verts = [v.co.copy() for v in bm.verts]
    bm.free()
    ev.to_mesh_clear()
    return t, verts


def main():
    sc = bpy.context.scene
    root = bpy.data.objects["CanisterStation_Root"]
    body = bpy.data.objects["SM_CanisterStation_Body"]
    can = bpy.data.objects["SM_CanisterStation_Canister"]
    rep = {"drivers": {}, "travel": {}, "clashes": [], "audit": {}}
    for fc in can.animation_data.drivers:
        d = fc.driver
        rep["drivers"]["location[%d]" % fc.array_index] = dict(valid=d.is_valid, simple=d.is_simple_expression,
                                                               expression=d.expression)
    if root.animation_data:
        root.animation_data.action = None
    dg = bpy.context.evaluated_depsgraph_get()
    tb, _ = bvh(body, dg)
    gap, where = 1e9, None
    for k in range(101):
        root["eject"] = k / 100.0
        root.update_tag()                         # a property set from Python is not tagged by itself
        sc.frame_set(1 + (k % 2))
        dg = bpy.context.evaluated_depsgraph_get()
        dg.update()
        tc, vc = bvh(can, dg)
        pairs = tc.overlap(tb)
        n = len(pairs)
        if n:
            c = dict(eject=k / 100.0, pairs=n)
            if not rep["clashes"]:                # where, the first time: the body's faces and their materials
                me = body.data
                names = [m.name for m in me.materials]
                hit = sorted({j for _, j in pairs})[:12]
                c["body_faces"] = [(names[me.polygons[j].material_index],
                                    [round(x, 3) for x in body.matrix_world @ me.polygons[j].center]) for j in hit]
            rep["clashes"].append(c)
        for v in vc[::2]:
            hit = tb.find_nearest(v)
            if hit[0] is not None and hit[3] < gap:
                gap, where = hit[3], (k / 100.0, [round(c, 3) for c in v])
        if k in (0, 50, 100):
            rep["travel"]["eject %.2f" % (k / 100)] = [round(c, 5) for c in can.evaluated_get(dg).matrix_world.translation]
    rep["smallest_gap_mm"] = round(gap * 1000, 2)
    rep["smallest_gap_at"] = where
    for ob in (body, can):
        rep["audit"][ob.name] = audit(ob)
    with open(os.path.join(HERE, "check_report.json"), "w") as fh:
        json.dump(rep, fh, indent=1)
    print("CHECK OK" if not rep["clashes"] else "CHECK CLASH", json.dumps(rep))


main()