import subprocess
import urllib.request
import urllib.error

from time import sleep
from threading import Lock
import http.client


_print_lock = Lock()


def safe_print(*args, **kwargs):
    with _print_lock:
        print(*args, **kwargs)


def run(args: list, **kwargs):
    p = subprocess.run(args, **kwargs)
    if p.returncode != 0:
        raise OSError(f'convert returned {p.returncode} ('+' '.join(args)+')')


def download_file(url, output, handle_http_errors=True) -> bool:
    tries_left = 3
    ok = False
    while tries_left > 0:
        try:
            urllib.request.urlretrieve(url, output)
            ok = True
            break
        except http.client.RemoteDisconnected:
            ok = False
            print('    caught an exception, sleeping for 2 seconds and retrying...')
            sleep(2)
            tries_left -= 1
        except urllib.error.HTTPError as e:
            if not handle_http_errors:
                raise e
            else:
                print(f'    failed to download {url}: {str(e)}')
                return False
    return ok