import subprocess
import tempfile

from shutil import which

DEPENDENCIES = ('pdftoppm',)
IMAGE_OPENER = 'ristretto'


def ensure_dependencies():
    for s in DEPENDENCIES:
        if which(s) is None:
            return RuntimeError(f'required dependency not found: {s}')


def randomtempname(suffix=None):
    name = next(tempfile._get_candidate_names())
    if suffix is not None:
        name += suffix
    return name


def desktop_open_image(f):
    subprocess.run([IMAGE_OPENER, f])