#!/usr/bin/env python3
"""Find VFMSH tiles intersecting a small region without reading mesh payloads."""
import argparse
import glob
import os
import resource
import struct


def main():
    parser = argparse.ArgumentParser()
    parser.add_argument("directory")
    parser.add_argument("--lod", type=int, required=True)
    parser.add_argument("--bounds", nargs=6, type=float, required=True,
                        metavar=("XMIN", "XMAX", "YMIN", "YMAX", "ZMIN", "ZMAX"))
    args = parser.parse_args()
    xmin, xmax, ymin, ymax, zmin, zmax = args.bounds
    matches = 0
    for path in sorted(glob.glob(os.path.join(args.directory, "*.vfmesh"))):
        with open(path, "rb") as stream:
            if stream.read(8) != b"VFMSH001":
                continue
            version, voxel_um, tile_count = struct.unpack("<3I", stream.read(12))
            stream.seek(40, 1)
            if version != 1:
                continue
            for _ in range(tile_count):
                key = struct.unpack("<4i", stream.read(16))
                surface_count, _, vertex_count, index_count, mask_count = struct.unpack(
                    "<5I", stream.read(20))
                extent = 32.0 * (1 << key[3]) * voxel_um / 1_000_000.0
                x0, y0, z0 = (key[axis] * extent for axis in range(3))
                intersects = (key[3] == args.lod and index_count > 0
                    and x0 <= xmax and x0 + extent >= xmin
                    and y0 <= ymax and y0 + extent >= ymin
                    and z0 <= zmax and z0 + extent >= zmin)
                if intersects:
                    matches += 1
                    print(f"[VFMeshTileWindow] scene={os.path.basename(path)} key={key} "
                          f"vertices={vertex_count} indices={index_count} "
                          f"extent_m={extent:.3f}")
                stream.seek(vertex_count * 24 + index_count * 4 + mask_count, 1)
    print(f"[VFMeshTileWindowSummary] matching_tiles={matches} "
          f"peak_rss_kib={resource.getrusage(resource.RUSAGE_SELF).ru_maxrss}")


if __name__ == "__main__":
    main()