import logging
from pathlib import Path

from sqlalchemy.orm import Session

from app.models.stl_cache import StlCache

logger = logging.getLogger("pops")

_ANALYSABLE = {".stl", ".3mf"}


def analyse(filename: str, db: Session) -> StlCache | None:
    """Return cached analysis for filename, computing it if missing."""
    existing = db.query(StlCache).filter(StlCache.filename == filename).first()
    if existing:
        return existing

    from app.stl import get_stl_dir
    filepath = get_stl_dir() / filename
    if Path(filename).suffix.lower() not in _ANALYSABLE or not filepath.exists():
        return None

    try:
        import trimesh
        mesh = trimesh.load(str(filepath), force="mesh")
        extents = mesh.extents          # [size_x, size_y, size_z] in mm
        volume_mm3 = abs(mesh.volume)   # mm³ (negative for inverted normals)
        entry = StlCache(
            filename=filename,
            cube_x=round(float(extents[0]), 2),
            cube_y=round(float(extents[1]), 2),
            cube_z=round(float(extents[2]), 2),
            volume_ccm=round(volume_mm3 / 1000, 3),
        )
        db.add(entry)
        db.commit()
        return entry
    except Exception:
        logger.exception("STL analysis failed for %s", filename)
        return None


def get_cache_map(filenames: list[str], db: Session) -> dict[str, StlCache]:
    """Bulk-fetch cached entries for a list of filenames."""
    rows = db.query(StlCache).filter(StlCache.filename.in_(filenames)).all()
    return {r.filename: r for r in rows}