#!/usr/bin/env python
"""Bake the wrapper-node normalization of filtered_lowpoly_rig/meshes into
vertex data, writing self-normalized GLBs to meshes_norm/.

Input files are known products of filter_meshes.py: single scene root
"__normalized_root__" with uniform scale s + translation t (no rotation).
We remove the wrapper and bake W = T(t)*S(s) so that spec-correct world-space
output is EXACTLY unchanged while raw accessor data becomes normalized:

  node translations *= s (old roots += t)   =>  G' = W * G * D^-1
  skinned positions  p'' = (W*C) p, C = G_j0*IBM_j0 (any invertible C is
    exact):  IBM' = D * IBM * C^-1 * W^-1
  static non-skinned positions p'' = (W*G_node) p, mesh moved to an identity
    root (skipped for meshes on joint/animated nodes: those keep p*=s so they
    still follow their node)
  animation translation outputs *= s (+t on old roots; CUBICSPLINE tangents
    *= s only)
  normals by inverse-transpose, tangents by linear part, morph deltas by
  linear part; POSITION min/max recomputed.

Per-file fallback scheme A (M = D everywhere, nothing moved) when accessors
are shared across conflicting groups or IBMs are absent/unreadable.
Quantized/sparse POSITION: file copied unchanged with wrapper kept.
Every output is verified: skinning-evaluated world vertices before vs after,
compared per (mesh, primitive).
"""
import json
import os
import struct
import sys
import time
from multiprocessing import Pool
from pathlib import Path

import numpy as np

SRC_DIR = Path("/root/zhaotianhao/filtered_lowpoly_rig/meshes")
DST_DIR = Path("/root/zhaotianhao/filtered_lowpoly_rig/meshes_norm")
REPORT = Path("/root/zhaotianhao/filtered_lowpoly_rig/bake_report.jsonl")
JSON_CHUNK = 0x4E4F534A
BIN_CHUNK = 0x004E4942
FLOAT = 5126
WRAPPER_NAMES = {"__normalized_root__", "__normalize_root__"}
VERIFY_TOL = 5e-3


def read_glb(path):
    raw = open(path, "rb").read()
    if raw[:4] != b"glTF":
        raise ValueError("bad magic")
    off = 12
    gltf = None
    chunks = []
    while off + 8 <= len(raw):
        cl, ct = struct.unpack_from("<II", raw, off)
        payload = raw[off + 8: off + 8 + cl]
        if ct == JSON_CHUNK and gltf is None:
            gltf = json.loads(payload)
            chunks.append([ct, None])
        else:
            chunks.append([ct, bytearray(payload)])
        off += 8 + cl
    return gltf, chunks


def write_glb(path, gltf, chunks):
    jb = json.dumps(gltf, separators=(",", ":")).encode()
    jb += b" " * ((4 - len(jb) % 4) % 4)
    body = b""
    for ct, payload in chunks:
        if ct == JSON_CHUNK and payload is None:
            payload = jb
        payload = bytes(payload)
        if len(payload) % 4:
            payload += (b"\x00" if ct == BIN_CHUNK else b" ") * (4 - len(payload) % 4)
        body += struct.pack("<II", len(payload), ct) + payload
    blob = struct.pack("<4sII", b"glTF", 2, 12 + len(body)) + body
    tmp = str(path) + ".part"
    with open(tmp, "wb") as f:
        f.write(blob)
    os.replace(tmp, path)


NCOMP = {"SCALAR": 1, "VEC2": 2, "VEC3": 3, "VEC4": 4, "MAT4": 16}


def acc_view(gltf, bin_ba, ai):
    acc = gltf["accessors"][ai]
    if acc.get("componentType") != FLOAT or "sparse" in acc or "bufferView" not in acc:
        return None
    n = NCOMP.get(acc.get("type"))
    if n is None:
        return None
    bv = gltf["bufferViews"][acc["bufferView"]]
    if bv.get("buffer", 0) != 0:
        return None
    stride = bv.get("byteStride") or 4 * n
    off = bv.get("byteOffset", 0) + acc.get("byteOffset", 0)
    count = acc["count"]
    if off + (count - 1) * stride + 4 * n > len(bin_ba):
        return None
    return np.ndarray((count, n), dtype="<f4", buffer=memoryview(bin_ba),
                      offset=off, strides=(stride, 4))


def node_matrix(node):
    if "matrix" in node:
        return np.array(node["matrix"], dtype=np.float64).reshape(4, 4).T
    m = np.eye(4)
    if "rotation" in node:
        x, y, z, w = node["rotation"]
        nq = x * x + y * y + z * z + w * w
        if nq > 1e-12:
            f = 2.0 / nq
            m[:3, :3] = np.array([
                [1 - (y * y + z * z) * f, (x * y - w * z) * f, (x * z + w * y) * f],
                [(x * y + w * z) * f, 1 - (x * x + z * z) * f, (y * z - w * x) * f],
                [(x * z - w * y) * f, (y * z + w * x) * f, 1 - (x * x + y * y) * f]])
    if "scale" in node:
        m[:3, :3] = m[:3, :3] * np.asarray(node["scale"], dtype=np.float64)
    if "translation" in node:
        m[:3, 3] = node["translation"]
    return m


def globals_from(gltf, roots):
    out = {}
    stack = [(r, np.eye(4)) for r in roots]
    while stack:
        ni, pm = stack.pop()
        if ni in out:
            continue
        g = pm @ node_matrix(gltf["nodes"][ni])
        out[ni] = g
        for c in gltf["nodes"][ni].get("children", []):
            stack.append((c, g))
    return out


def scale_node_translation(node, s, add=None):
    if "matrix" in node:
        mm = list(node["matrix"])
        for k in (12, 13, 14):
            mm[k] = mm[k] * s
        if add is not None:
            mm[12] += add[0]; mm[13] += add[1]; mm[14] += add[2]
        node["matrix"] = mm
    else:
        t = [v * s for v in node.get("translation", [0.0, 0.0, 0.0])]
        if add is not None:
            t = [t[0] + add[0], t[1] + add[1], t[2] + add[2]]
        if any(abs(v) > 1e-12 for v in t) or "translation" in node or add is not None:
            node["translation"] = t


def world_verts(gltf, bin_ba, roots):
    """Spec-correct world vertices keyed by (mesh, prim). None if unsupported."""
    G = globals_from(gltf, roots)
    out = {}
    for ni in sorted(G):
        g = G[ni]
        nd = gltf["nodes"][ni]
        mi = nd.get("mesh")
        if mi is None:
            continue
        si = nd.get("skin")
        for pk, prim in enumerate(gltf["meshes"][mi].get("primitives", [])):
            key = (mi, pk)
            if key in out:
                continue
            pa = prim.get("attributes", {}).get("POSITION")
            if pa is None:
                continue
            P = acc_view(gltf, bin_ba, pa)
            if P is None:
                return None
            P = P[:, :3].astype(np.float64)
            if si is None:
                out[key] = P @ g[:3, :3].T + g[:3, 3]
                continue
            skin = gltf["skins"][si]
            joints = skin["joints"]
            ibm_ai = skin.get("inverseBindMatrices")
            if ibm_ai is None:
                IBM = np.tile(np.eye(4), (len(joints), 1, 1))
            else:
                raw = acc_view(gltf, bin_ba, ibm_ai)
                if raw is None:
                    return None
                IBM = raw.astype(np.float64).reshape(-1, 4, 4).transpose(0, 2, 1)
            JM = np.stack([G.get(j, np.eye(4)) @ IBM[k]
                           for k, j in enumerate(joints)])
            ja = prim["attributes"].get("JOINTS_0")
            wa = prim["attributes"].get("WEIGHTS_0")
            if ja is None or wa is None:
                out[key] = P @ g[:3, :3].T + g[:3, 3]
                continue
            jacc = gltf["accessors"][ja]
            jbv = gltf["bufferViews"][jacc["bufferView"]]
            dt = {5121: np.uint8, 5123: np.uint16, 5125: np.uint32}.get(
                jacc["componentType"])
            if dt is None:
                return None
            isz = np.dtype(dt).itemsize
            stride = jbv.get("byteStride") or 4 * isz
            off = jbv.get("byteOffset", 0) + jacc.get("byteOffset", 0)
            J = np.ndarray((jacc["count"], 4), dtype=dt, buffer=memoryview(bin_ba),
                           offset=off, strides=(stride, isz)).astype(np.int64)
            Wt = acc_view(gltf, bin_ba, wa)
            if Wt is None:
                return None
            Wt = Wt.astype(np.float64)
            Wn = Wt / np.maximum(Wt.sum(1, keepdims=True), 1e-9)
            J = np.clip(J, 0, len(joints) - 1)
            M = (JM[J] * Wn[..., None, None]).sum(1)
            hp = np.concatenate([P, np.ones((len(P), 1))], 1)
            out[key] = np.einsum("nij,nj->ni", M, hp)[:, :3]
    return out


def bake_one(name):
    src = SRC_DIR / name
    dst = DST_DIR / name
    rec = {"file": name}
    try:
        gltf, chunks = read_glb(src)
        bin_ba = next((p for ct, p in chunks if ct == BIN_CHUNK), None)
        nodes = gltf["nodes"]
        scene = gltf["scenes"][gltf.get("scene", 0)]
        sroots = scene.get("nodes", [])
        if len(sroots) != 1 or nodes[sroots[0]].get("name") not in WRAPPER_NAMES:
            rec.update(status="error", reason="no_wrapper"); return rec
        wi = sroots[0]
        wrap = nodes[wi]
        s = float(wrap.get("scale", [1, 1, 1])[0])
        t = np.array(wrap.get("translation", [0, 0, 0]), dtype=np.float64)
        old_roots = list(wrap.get("children", []))
        W = np.eye(4); W[:3, :3] *= s; W[:3, 3] = t
        D = np.eye(4); D[:3, :3] *= s
        Dinv = np.eye(4); Dinv[:3, :3] /= s
        Winv = np.linalg.inv(W)

        v_before = world_verts(gltf, bin_ba, [wi])
        G = globals_from(gltf, old_roots)
        accessors = gltf["accessors"]

        joints_all = set()
        for sk in gltf.get("skins", []):
            joints_all.update(sk.get("joints", []))
        anim_nodes = set()
        for anim in gltf.get("animations", []):
            for ch in anim.get("channels", []):
                tgt = ch.get("target", {})
                if tgt.get("path") in ("translation", "rotation", "scale"):
                    anim_nodes.add(tgt.get("node"))
        # nodes whose world transform can change at runtime
        dyn = set()
        stack = [(r, False) for r in old_roots]
        while stack:
            ni, flag = stack.pop()
            flag = flag or ni in anim_nodes or ni in joints_all
            if flag:
                dyn.add(ni)
            for c in nodes[ni].get("children", []):
                stack.append((c, flag))

        full_ok = bin_ba is not None
        mesh_owner = {}   # mesh -> (node, skin, G, movable)
        for ni in sorted(G):
            nd = nodes[ni]
            mi = nd.get("mesh")
            if mi is None:
                continue
            movable = ni not in dyn
            if mi in mesh_owner:
                p_ni, p_si, p_g, p_mv = mesh_owner[mi]
                if p_si != nd.get("skin") or not np.allclose(p_g, G[ni], atol=1e-6):
                    full_ok = False
                mesh_owner[mi] = (p_ni, p_si, p_g, p_mv and movable)
            else:
                mesh_owner[mi] = (ni, nd.get("skin"), G[ni], movable)

        skin_C = {}
        if full_ok:
            for si, skin in enumerate(gltf.get("skins", [])):
                ibm_ai = skin.get("inverseBindMatrices")
                raw = acc_view(gltf, bin_ba, ibm_ai) if ibm_ai is not None else None
                if raw is None:
                    full_ok = False; break
                j0 = skin["joints"][0]
                IBM0 = raw[0].astype(np.float64).reshape(4, 4).T
                C = G.get(j0, np.eye(4)) @ IBM0
                if not np.all(np.isfinite(C)) or abs(np.linalg.det(C)) < 1e-12:
                    C = np.eye(4)
                skin_C[si] = C

        def group_key(mi):
            ni, si, g, movable = mesh_owner[mi]
            if si is not None:
                return ("s", si)
            return ("n", ni) if movable else ("d",)

        if full_ok:
            acc_grp = {}
            for mi in mesh_owner:
                key = group_key(mi)
                for prim in gltf["meshes"][mi].get("primitives", []):
                    sets = [prim.get("attributes", {})] + prim.get("targets", [])
                    for aset in sets:
                        for an in ("POSITION", "NORMAL", "TANGENT"):
                            ai = aset.get(an)
                            if ai is None:
                                continue
                            if acc_grp.get(ai, key) != key:
                                full_ok = False
                            acc_grp[ai] = key
                    pa = prim.get("attributes", {}).get("POSITION")
                    if pa is not None and acc_view(gltf, bin_ba, pa) is None:
                        rec.update(status="kept_wrapper",
                                   reason="unbakeable_positions")
                        write_glb(dst, gltf, chunks)
                        return rec

        scheme = "full" if full_ok else "A"

        # ---- 1. node translations ----
        for ni in G:
            scale_node_translation(nodes[ni], s,
                                   add=t.tolist() if ni in old_roots else None)

        # ---- 2. vertex data ----
        done_acc = set()
        for mi, (ni, si, g, movable) in mesh_owner.items():
            if scheme == "full":
                if si is not None:
                    M = W @ skin_C[si]
                elif movable:
                    M = W @ g
                else:
                    M = D
            else:
                M = D
            L = M[:3, :3]
            if abs(np.linalg.det(L)) < 1e-15:
                # degenerate node transform: keep mesh in place, scale only
                M = D
                L = M[:3, :3]
                mesh_owner[mi] = (ni, si, g, False)
            Mt = M[:3, 3]
            it = np.linalg.inv(L).T
            for prim in gltf["meshes"][mi].get("primitives", []):
                attrs = prim.get("attributes", {})
                sets = [(attrs, False)] + [(tg, True) for tg in prim.get("targets", [])]
                for aset, is_delta in sets:
                    for an in ("POSITION", "NORMAL", "TANGENT"):
                        ai = aset.get(an)
                        if ai is None or ai in done_acc:
                            continue
                        done_acc.add(ai)
                        V = acc_view(gltf, bin_ba, ai)
                        if V is None:
                            continue
                        if an == "POSITION":
                            X = V[:, :3].astype(np.float64) @ L.T
                            if not is_delta:
                                X = X + Mt
                            V[:, :3] = X.astype(np.float32)
                            acc = accessors[ai]
                            acc["min"] = np.min(V[:, :3], 0).astype(float).tolist()
                            acc["max"] = np.max(V[:, :3], 0).astype(float).tolist()
                        elif scheme == "full":
                            R3 = it if an == "NORMAL" else L
                            X = V[:, :3].astype(np.float64) @ R3.T
                            nn = np.linalg.norm(X, axis=1, keepdims=True)
                            V[:, :3] = (X / np.maximum(nn, 1e-12)).astype(np.float32)

        # ---- 3. IBMs ----
        for si, skin in enumerate(gltf.get("skins", [])):
            ibm_ai = skin.get("inverseBindMatrices")
            if ibm_ai is None:
                if scheme == "full":
                    rec.update(status="error", reason="ibm_missing_full"); return rec
                continue
            raw = acc_view(gltf, bin_ba, ibm_ai)
            if raw is None:
                rec.update(status="error", reason="ibm_unreadable"); return rec
            R = (np.linalg.inv(skin_C[si]) @ Winv) if scheme == "full" else Dinv
            for k in range(len(raw)):
                ib = raw[k].astype(np.float64).reshape(4, 4).T
                raw[k] = (D @ ib @ R).T.reshape(16).astype(np.float32)

        # ---- 4. animation translation outputs ----
        anim_shared = False
        out_rule = {}
        for anim in gltf.get("animations", []):
            samplers = anim.get("samplers", [])
            for ch in anim.get("channels", []):
                tgt = ch.get("target", {})
                if tgt.get("path") != "translation":
                    continue
                sm = samplers[ch["sampler"]]
                rule = (tgt.get("node") in old_roots,
                        sm.get("interpolation") == "CUBICSPLINE")
                oa = sm["output"]
                if out_rule.get(oa, rule) != rule:
                    anim_shared = True
                out_rule[oa] = rule
        for oa, (is_root, cubic) in out_rule.items():
            V = acc_view(gltf, bin_ba, oa)
            if V is None:
                continue
            V[:] = V[:] * s
            if is_root:
                if cubic:
                    V[1::3, :3] += t.astype(np.float32)
                else:
                    V[:, :3] += t.astype(np.float32)

        # ---- 5. restructure scene ----
        new_roots = list(old_roots)
        if scheme == "full":
            parent = {}
            for ni in G:
                for c in nodes[ni].get("children", []):
                    parent[c] = ni
            newG = globals_from(gltf, old_roots)
            for mi, (ni, si, g, movable) in mesh_owner.items():
                if si is None and movable:
                    for nj in G:
                        if nodes[nj].get("mesh") == mi:
                            nodes[nj].pop("mesh", None)
                    nodes.append({"name": "baked_mesh_%d" % mi, "mesh": mi})
                    new_roots.append(len(nodes) - 1)
                elif (si is not None and not nodes[ni].get("children")
                      and ni not in joints_all and ni not in anim_nodes):
                    pg = newG.get(parent.get(ni), np.eye(4)) if ni in parent \
                        else np.eye(4)
                    try:
                        inv = np.linalg.inv(pg)
                    except np.linalg.LinAlgError:
                        continue
                    nd = nodes[ni]
                    for k in ("matrix", "translation", "rotation", "scale"):
                        nd.pop(k, None)
                    if not np.allclose(inv, np.eye(4), atol=1e-9):
                        nd["matrix"] = inv.T.reshape(16).tolist()

        scene["nodes"] = new_roots
        wrap.pop("children", None)
        wrap.pop("scale", None)
        wrap.pop("translation", None)
        if wi == len(nodes) - 1:
            nodes.pop()

        # ---- verify ----
        v_after = world_verts(gltf, bin_ba, new_roots)
        err = None
        if v_before is not None and v_after is not None:
            errs = [float(np.abs(v_before[k] - v_after[k]).max())
                    for k in v_before if k in v_after
                    and v_before[k].shape == v_after[k].shape]
            if len(errs) != len(v_before) or len(v_before) != len(v_after):
                rec.update(status="error", reason="verify_key_mismatch"); return rec
            err = max(errs) if errs else 0.0
            if err > VERIFY_TOL:
                rec.update(status="error", reason="verify_failed", max_err=err)
                return rec
        lo = hi = None
        if v_after:
            allv = np.concatenate(list(v_after.values()), 0)
            lo, hi = float(allv.min()), float(allv.max())

        write_glb(dst, gltf, chunks)
        rec.update(status="ok", scheme=scheme, max_err=err,
                   anim_shared=anim_shared, world_min=lo, world_max=hi)
        return rec
    except Exception as e:  # noqa: BLE001
        rec.update(status="error", reason="exc:%s:%s" % (type(e).__name__, e))
        return rec


def main():
    import argparse
    ap = argparse.ArgumentParser()
    ap.add_argument("--limit", type=int, default=0)
    ap.add_argument("--workers", type=int, default=16)
    args = ap.parse_args()
    DST_DIR.mkdir(parents=True, exist_ok=True)
    names = sorted(os.listdir(SRC_DIR))
    done = set(os.listdir(DST_DIR))
    todo = [n for n in names if n not in done and n.endswith(".glb")]
    if args.limit:
        todo = todo[: args.limit]
    print("[bake] %d total, %d todo" % (len(names), len(todo)), flush=True)
    stats = {}
    t0 = time.time()
    with open(REPORT, "a") as rep, Pool(args.workers) as pool:
        for i, rec in enumerate(pool.imap_unordered(bake_one, todo, chunksize=8), 1):
            key = rec["status"] + (":" + rec.get("reason", "") if rec["status"] == "error"
                                   else ":" + rec.get("scheme", rec.get("reason", "")))
            stats[key] = stats.get(key, 0) + 1
            if rec["status"] != "ok" or i % 2000 == 0:
                rep.write(json.dumps(rec) + "\n")
                rep.flush()
            if i % 2000 == 0:
                print("[bake] %d/%d (%.0f/s) %s" % (
                    i, len(todo), i / max(time.time() - t0, 1e-9), stats), flush=True)
    print("[bake] DONE %s" % stats, flush=True)


if __name__ == "__main__":
    sys.exit(main())