"""Check the vat: separate parts against each other, topology. Nothing is saved.

    blender.exe -b ../NutritionVat.blend --python nv_check.py      -> build/check_report.json

Triangle overlap in world space (BVH) between every pair of separate meshes: the body, the liquid, the two canisters
and the hoses; the hoses also tube against tube. Smallest gaps from the liquid to the glass and from the canisters to
their clamp rings. Topology of each mesh.
"""
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, "nv_lib.py")).read())


def world_bm(ob):
    bm = bmesh.new()
    bm.from_mesh(ob.data)
    bm.transform(ob.matrix_world)
    return bm


def tree(ob):
    bm = world_bm(ob)
    t = BVHTree.FromBMesh(bm)
    vs = [v.co.copy() for v in bm.verts]
    bm.free()
    return t, vs


def parts_of(ob):
    """one BVH per connected piece (the hoses' tubes)"""
    bm = world_bm(ob)
    bm.verts.ensure_lookup_table()
    seen, out = set(), []
    for v0 in bm.verts:
        if v0.index in seen:
            continue
        comp, stack = [], [v0]
        seen.add(v0.index)
        while stack:
            v = stack.pop()
            comp.append(v)
            for e in v.link_edges:
                w = e.other_vert(v)
                if w.index not in seen:
                    seen.add(w.index)
                    stack.append(w)
        ids = {v.index for v in comp}
        faces = [f for f in bm.faces if f.verts[0].index in ids]
        out.append(BVHTree.FromPolygons([v.co.copy() for v in bm.verts], [[v.index for v in f.verts] for f in faces]))
    bm.free()
    return out


def gap(verts, t):
    best = 1e9
    for v in verts:
        hit = t.find_nearest(v)
        if hit[0] is not None:
            best = min(best, hit[3])
    return best


def main():
    bpy.context.view_layer.update()
    obs = {n: bpy.data.objects[n] for n in ("SM_NutritionVat_Body", "SM_NutritionVat_Fluid", "NutritionVat_Canister_R",
                                             "NutritionVat_Canister_L", "SM_NutritionVat_Hoses")}
    T = {n: tree(o) for n, o in obs.items()}
    rep = {"overlaps": {}, "gaps_mm": {}, "audit": {}}
    names = list(obs)
    for i in range(len(names)):
        for j in range(i + 1, len(names)):
            a, b = names[i], names[j]
            rep["overlaps"]["%s x %s" % (a, b)] = len(T[a][0].overlap(T[b][0]))
    tubes = parts_of(obs["SM_NutritionVat_Hoses"])
    hh = 0
    pairs = []
    for i in range(len(tubes)):
        for j in range(i + 1, len(tubes)):
            n = len(tubes[i].overlap(tubes[j]))
            if n:
                hh += n
                pairs.append((i, j, n))
    rep["overlaps"]["hose x hose"] = hh
    rep["hose_pairs_touching"] = pairs
    rep["hoses"] = len(tubes)
    rep["gaps_mm"]["liquid to body (glass)"] = round(gap(T["SM_NutritionVat_Fluid"][1], T["SM_NutritionVat_Body"][0]) * 1000, 2)
    for c in ("NutritionVat_Canister_R", "NutritionVat_Canister_L"):
        rep["gaps_mm"][c + " to body"] = round(gap(T[c][1], T["SM_NutritionVat_Body"][0]) * 1000, 2)
    rep["gaps_mm"]["hoses to body"] = round(gap(T["SM_NutritionVat_Hoses"][1][::4], T["SM_NutritionVat_Body"][0]) * 1000, 2)
    for n, o in obs.items():
        rep["audit"][n] = audit(o)
    clash = sum(v for v in rep["overlaps"].values())
    rep["clash_pairs_total"] = clash
    with open(os.path.join(HERE, "check_report.json"), "w") as fh:
        json.dump(rep, fh, indent=1)
    print("CHECK OK" if not clash else "CHECK CLASH", json.dumps(rep))


main()