"""EXIF-aware dimensions without decoding original photo pixels."""

import os
import stat
from pathlib import Path

from PIL import Image, UnidentifiedImageError


def dimensions(root: Path, path: Path):
    parent_fd = os.open(root, os.O_RDONLY | os.O_DIRECTORY)
    try:
        parts = path.relative_to(root).parts
        for part in parts[:-1]:
            child = os.open(
                part, os.O_RDONLY | os.O_DIRECTORY | os.O_NOFOLLOW, dir_fd=parent_fd
            )
            os.close(parent_fd)
            parent_fd = child
        fd = os.open(
            parts[-1], os.O_RDONLY | os.O_NOFOLLOW | os.O_NONBLOCK, dir_fd=parent_fd
        )
        with os.fdopen(fd, "rb") as stream:
            if not stat.S_ISREG(os.fstat(stream.fileno()).st_mode):
                return None
            with Image.open(stream) as image:
                width, height = image.size
                if image.getexif().get(274, 1) in (5, 6, 7, 8):
                    width, height = height, width
                return width, height
    except (OSError, ValueError, UnidentifiedImageError, Image.DecompressionBombError):
        return None
    finally:
        os.close(parent_fd)


def orientation(width, height):
    return "landscape" if width > height else "portrait" if height > width else "square"