#!/usr/bin/env python
# -*- coding: utf-8 -*-
"""
Filter rigged low-poly meshes from multiple datasets.

A .glb is kept only if ALL of:
  - valid glTF 2.0 binary
  - has skins with joints, and at least one scene-reachable node binds mesh+skin
  - total vertex count of scene-reachable meshes < 10000

Kept meshes are normalized into [-0.5, 0.5]^3 by inserting a wrapper root node
(uniform scale + translation) into the scene graph. This preserves skeleton /
skin / animation data exactly (a re-export through trimesh would drop them).

Dedup: exact file sha256 + geometry hash over POSITION/JOINTS_0/WEIGHTS_0
buffer bytes. Sources are opened read-only; all output goes under OUT_ROOT.
Resumable: paths already listed in processed.log are skipped on restart.

Run:  python filter_meshes.py [--limit-per-source N]
"""
import argparse
import hashlib
import itertools
import json
import os
import struct
import sys
import time
from collections import Counter
from multiprocessing import Pool
from pathlib import Path

import numpy as np

# highest priority first: when duplicates exist, the earlier source wins
SOURCES = [
    ("dataset_rig", "/root/zhaotianhao/dataset_rig"),
    ("canoverse", "/root/youjiaZhang/topotex_data_CanoVerse/raw"),
    ("objaverse_xl", "/root/dataset/dataset.2/objaverse-xl/hf-objaverse-v1/glbs"),
]

OUT_ROOT = Path("/root/zhaotianhao/filtered_lowpoly_rig")
MESH_DIR = OUT_ROOT / "meshes"
TMP_DIR = OUT_ROOT / "tmp"
MANIFEST = OUT_ROOT / "manifest.jsonl"
PROCESSED = OUT_ROOT / "processed.log"
STATS = OUT_ROOT / "stats.json"

MAX_VERTS = 10000          # strict: keep only n_verts < MAX_VERTS
NORM_HALF = 0.5            # normalize longest axis into [-NORM_HALF, NORM_HALF]
MAX_FILE_BYTES = 300 << 20 # skip pathological files
WORKERS = 24
MESH_EXTS = {".glb", ".gltf", ".vrm", ".fbx", ".obj", ".dae", ".ply", ".stl"}

CHUNK_JSON = 0x4E4F534A
CHUNK_BIN = 0x004E4942


def _quat_to_mat(x, y, z, w):
    n = x * x + y * y + z * z + w * w
    if n < 1e-12:
        return np.eye(3)
    s = 2.0 / n
    xx, yy, zz = x * x * s, y * y * s, z * z * s
    xy, xz, yz = x * y * s, x * z * s, y * z * s
    wx, wy, wz = w * x * s, w * y * s, w * z * s
    return np.array([
        [1 - (yy + zz), xy - wz, xz + wy],
        [xy + wz, 1 - (xx + zz), yz - wx],
        [xz - wy, yz + wx, 1 - (xx + yy)],
    ])


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 "scale" in node:
        m[:3, :3] = np.diag(node["scale"])
    if "rotation" in node:
        x, y, z, w = node["rotation"]
        m[:3, :3] = _quat_to_mat(x, y, z, w) @ m[:3, :3]
    if "translation" in node:
        m[:3, 3] = node["translation"]
    return m


def _reject(rec, reason, **extra):
    rec.update(status="reject", reason=reason, **extra)
    return rec


def process_one(task):
    tag, path = task
    rec = {"src": path, "tag": tag}
    try:
        return _process_one(tag, path, rec)
    except Exception as e:  # noqa: BLE001 - any parse failure is a data reject
        return _reject(rec, "error:%s" % type(e).__name__)


def _process_one(tag, path, rec):
    ext = os.path.splitext(path)[1].lower()
    if ext != ".glb":
        # .obj cannot embed skin/skeleton; .fbx would need blender (unavailable)
        return _reject(rec, "non_glb:%s" % ext.lstrip("."))
    size = os.path.getsize(path)
    if size > MAX_FILE_BYTES:
        return _reject(rec, "too_large")

    fhash = hashlib.sha256()
    with open(path, "rb") as f:
        hdr = f.read(12)
        if len(hdr) < 12 or hdr[:4] != b"glTF":
            return _reject(rec, "bad_magic")
        version, _total = struct.unpack("<II", hdr[4:])
        if version != 2:
            return _reject(rec, "gltf_v%d" % version)
        ch = f.read(8)
        if len(ch) < 8:
            return _reject(rec, "truncated")
        clen, ctype = struct.unpack("<II", ch)
        if ctype != CHUNK_JSON:
            return _reject(rec, "no_json_chunk")
        raw_json = f.read(clen)
        try:
            gltf = json.loads(raw_json)
        except Exception:
            return _reject(rec, "json_parse")

        # ---------- rig filter (cheap: JSON only) ----------
        skins = gltf.get("skins") or []
        joints_union = set()
        for s in skins:
            joints_union.update(s.get("joints") or [])
        if not joints_union:
            return _reject(rec, "no_skeleton")

        nodes = gltf.get("nodes") or []
        meshes = gltf.get("meshes") or []
        accessors = gltf.get("accessors") or []
        scenes = gltf.get("scenes") or []
        if not scenes:
            return _reject(rec, "no_scene")
        scene_idx = min(gltf.get("scene", 0), len(scenes) - 1)
        roots = scenes[scene_idx].get("nodes") or []
        if not roots:
            return _reject(rec, "empty_scene")

        mesh_nodes = []  # (node_index, world_matrix)
        has_skinned = False
        stack = [(r, np.eye(4)) for r in roots]
        seen = set()
        while stack:
            ni, pm = stack.pop()
            if ni in seen or not (0 <= ni < len(nodes)):
                continue
            seen.add(ni)
            nd = nodes[ni]
            wm = pm @ _node_matrix(nd)
            if nd.get("mesh") is not None:
                mesh_nodes.append((ni, wm))
                if nd.get("skin") is not None:
                    has_skinned = True
            for c in nd.get("children") or []:
                stack.append((c, wm))
        if not mesh_nodes:
            return _reject(rec, "no_mesh_in_scene")
        if not has_skinned:
            return _reject(rec, "no_skinned_mesh")

        # ---------- vertex budget ----------
        mesh_ids = sorted({nodes[ni]["mesh"] for ni, _ in mesh_nodes
                           if 0 <= nodes[ni]["mesh"] < len(meshes)})
        n_verts = 0
        n_faces = 0
        for mi in mesh_ids:
            for prim in meshes[mi].get("primitives") or []:
                pa = (prim.get("attributes") or {}).get("POSITION")
                if pa is None or not (0 <= pa < len(accessors)):
                    continue
                cnt = accessors[pa].get("count", 0)
                n_verts += cnt
                if prim.get("mode", 4) == 4:
                    ia = prim.get("indices")
                    if ia is not None and 0 <= ia < len(accessors):
                        n_faces += accessors[ia].get("count", 0) // 3
                    else:
                        n_faces += cnt // 3
        if n_verts == 0:
            return _reject(rec, "no_position")
        if n_verts >= MAX_VERTS:
            return _reject(rec, "too_many_verts", n_verts=n_verts)

        # ---------- world bbox from accessor min/max ----------
        mn = np.full(3, np.inf)
        mx = np.full(3, -np.inf)
        for ni, wm in mesh_nodes:
            mi = nodes[ni]["mesh"]
            if not (0 <= mi < len(meshes)):
                continue
            for prim in meshes[mi].get("primitives") or []:
                pa = (prim.get("attributes") or {}).get("POSITION")
                if pa is None or not (0 <= pa < len(accessors)):
                    continue
                acc = accessors[pa]
                amn, amx = acc.get("min"), acc.get("max")
                if not amn or not amx or len(amn) < 3 or len(amx) < 3:
                    return _reject(rec, "missing_bounds")
                cs = np.array(list(itertools.product(
                    (amn[0], amx[0]), (amn[1], amx[1]), (amn[2], amx[2]))))
                cs4 = np.hstack([cs, np.ones((8, 1))])
                w = (wm @ cs4.T).T[:, :3]
                mn = np.minimum(mn, w.min(axis=0))
                mx = np.maximum(mx, w.max(axis=0))
        extent = mx - mn
        max_extent = float(np.max(extent))
        if not np.isfinite(max_extent) or max_extent <= 1e-9:
            return _reject(rec, "degenerate_bbox")
        scale = (2.0 * NORM_HALF) / max_extent
        center = (mn + mx) / 2.0

        # ---------- read remaining chunks, hash file ----------
        fhash.update(hdr)
        fhash.update(ch)
        fhash.update(raw_json)
        rest = []
        while True:
            h = f.read(8)
            if len(h) < 8:
                break
            fhash.update(h)
            cl, ct = struct.unpack("<II", h)
            payload = f.read(cl)
            fhash.update(payload)
            rest.append((ct, payload))
    file_hash = fhash.hexdigest()

    bin_data = None
    for ct, payload in rest:
        if ct == CHUNK_BIN:
            bin_data = payload
            break

    # ---------- geometry hash (positions + skin binding bytes) ----------
    bvs = gltf.get("bufferViews") or []
    buffers = gltf.get("buffers") or []
    bin_usable = bin_data is not None and buffers and "uri" not in buffers[0]
    if bin_usable:
        gh = hashlib.sha256()
        gh.update(b"%d/%d/%d" % (n_verts, n_faces, len(joints_union)))
        for mi in mesh_ids:
            for prim in meshes[mi].get("primitives") or []:
                attrs = prim.get("attributes") or {}
                for name in ("POSITION", "JOINTS_0", "WEIGHTS_0"):
                    ai = attrs.get(name)
                    if ai is None or not (0 <= ai < len(accessors)):
                        continue
                    bvi = accessors[ai].get("bufferView")
                    if bvi is None or not (0 <= bvi < len(bvs)):
                        continue
                    bv = bvs[bvi]
                    if bv.get("buffer", 0) != 0:
                        continue
                    off = bv.get("byteOffset", 0)
                    gh.update(bin_data[off:off + bv.get("byteLength", 0)])
        geo_hash = gh.hexdigest()
    else:
        geo_hash = "file:" + file_hash

    # ---------- insert normalization wrapper node ----------
    wrapper = {
        "name": "__normalized_root__",
        "children": list(roots),
        "scale": [scale, scale, scale],
        "translation": [float(-center[0] * scale),
                        float(-center[1] * scale),
                        float(-center[2] * scale)],
    }
    gltf.setdefault("nodes", nodes).append(wrapper)
    scenes[scene_idx]["nodes"] = [len(gltf["nodes"]) - 1]

    new_json = json.dumps(gltf, separators=(",", ":")).encode("utf-8")
    new_json += b" " * ((4 - len(new_json) % 4) % 4)
    body = bytearray()
    for ct, payload in rest:
        if len(payload) % 4:
            payload = payload + b"\x00" * (4 - len(payload) % 4)
        body += struct.pack("<II", len(payload), ct)
        body += payload
    total = 12 + 8 + len(new_json) + len(body)
    blob = (struct.pack("<4sII", b"glTF", 2, total)
            + struct.pack("<II", len(new_json), CHUNK_JSON) + new_json + bytes(body))

    tmp = TMP_DIR / ("%d_%s.glb" % (os.getpid(), hashlib.md5(path.encode()).hexdigest()[:12]))
    tmp.write_bytes(blob)

    rec.update(
        status="accept", tmp=str(tmp), file_hash=file_hash, geo_hash=geo_hash,
        n_verts=n_verts, n_faces=n_faces, n_joints=len(joints_union),
        n_skins=len(skins), scale=round(scale, 6),
        bbox_min=[round(v, 5) for v in mn.tolist()],
        bbox_max=[round(v, 5) for v in mx.tolist()],
    )
    return rec


# ---------------------------------------------------------------- main driver

def iter_source_files(root):
    for dirpath, dirnames, filenames in os.walk(root):
        dirnames[:] = sorted(d for d in dirnames if not d.startswith("."))
        for fn in sorted(filenames):
            if os.path.splitext(fn)[1].lower() in MESH_EXTS:
                yield os.path.join(dirpath, fn)


def main():
    ap = argparse.ArgumentParser()
    ap.add_argument("--limit-per-source", type=int, default=0,
                    help="smoke test: only process first N files of each source")
    args = ap.parse_args()

    MESH_DIR.mkdir(parents=True, exist_ok=True)
    TMP_DIR.mkdir(parents=True, exist_ok=True)
    for stale in TMP_DIR.glob("*.glb"):
        stale.unlink(missing_ok=True)

    processed = set()
    if PROCESSED.exists():
        with open(PROCESSED) as f:
            processed = {ln.rstrip("\n") for ln in f}
    seen_file, seen_geo, used_names = set(), set(), set()
    if MANIFEST.exists():
        with open(MANIFEST) as f:
            for ln in f:
                try:
                    r = json.loads(ln)
                except Exception:
                    continue
                seen_file.add(r["file_hash"])
                seen_geo.add(r["geo_hash"])
                used_names.add(r["out"])
    print("[init] resume: %d processed, %d accepted so far"
          % (len(processed), len(seen_file)), flush=True)

    def tasks():
        for tag, root in SOURCES:
            it = iter_source_files(root)
            if args.limit_per_source:
                it = itertools.islice(it, args.limit_per_source)
            for p in it:
                if p not in processed:
                    yield (tag, p)

    stats = Counter()
    t0 = time.time()
    n_done = 0
    man_f = open(MANIFEST, "a")
    proc_f = open(PROCESSED, "a")

    def dump_stats():
        payload = {
            "done_this_run": n_done,
            "elapsed_sec": round(time.time() - t0, 1),
            "accepted_total": len(seen_file),
            "counts": dict(stats),
        }
        STATS.write_text(json.dumps(payload, indent=2))

    with Pool(WORKERS, maxtasksperchild=500) as pool:
        for rec in pool.imap(process_one, tasks(), chunksize=16):
            n_done += 1
            tag = rec["tag"]
            if rec["status"] == "reject":
                reason = rec["reason"].split(":")[0]
                stats["%s.reject.%s" % (tag, rec["reason"])] += 1
            else:
                tmp = Path(rec.pop("tmp"))
                if rec["file_hash"] in seen_file or rec["geo_hash"] in seen_geo:
                    tmp.unlink(missing_ok=True)
                    stats["%s.dup" % tag] += 1
                else:
                    seen_file.add(rec["file_hash"])
                    seen_geo.add(rec["geo_hash"])
                    stem = Path(rec["src"]).stem[:64]
                    name = stem + ".glb"
                    if name in used_names:
                        name = "%s_%s.glb" % (stem, rec["file_hash"][:8])
                    used_names.add(name)
                    os.replace(tmp, MESH_DIR / name)
                    rec["out"] = name
                    man_f.write(json.dumps(rec) + "\n")
                    stats["%s.accept" % tag] += 1
            proc_f.write(rec["src"] + "\n")
            if n_done % 200 == 0:
                man_f.flush()
                proc_f.flush()
            if n_done % 5000 == 0:
                acc = sum(v for k, v in stats.items() if k.endswith(".accept"))
                print("[%.0fs] %d files done, %d accepted, %d dup"
                      % (time.time() - t0, n_done, acc,
                         sum(v for k, v in stats.items() if k.endswith(".dup"))),
                      flush=True)
                dump_stats()

    man_f.close()
    proc_f.close()
    dump_stats()
    print("[DONE] %d files in %.0fs" % (n_done, time.time() - t0), flush=True)
    print(json.dumps(dict(stats), indent=2, sort_keys=True), flush=True)


if __name__ == "__main__":
    main()