import logging
import os
import subprocess
import time

import sau

def exec_cmd(cmd, timeout=900, env = None):
    my_env = os.environ.copy()
    if env:
        my_env.update(env)
    log = logging.getLogger(sau.LOGNAME)
    log.debug('Executing "{}"'.format(' '.join(cmd)))
    proc = subprocess.Popen(
            cmd,
            stdout=subprocess.PIPE,
            stderr=subprocess.PIPE,
            env = my_env)
    out = b""
    err = b""

    try:
        out, err = proc.communicate(timeout=timeout)
    except subprocess.TimeoutExpired as ex:
        log.error('Command "{}" timed out, killing it.'.format(' '.join(cmd)))
        proc.kill()
        time.sleep(30)
        if proc.poll() != None:
            log.error('Command "{}" would not be killed, forcing a termination'.format(' '.join(cmd)))
            proc.terminate()
            time.sleep(5)
    return (proc.returncode, out.decode('utf-8'), err.decode('utf-8'))


def version_diff(new, old):
    """ This will return the number of common fields in the version scheme,
    counted from the left. """
    new_list = list(new.split('.'))
    old_list = list(old.split('.'))
    common = min(len(new_list), len(old_list))
    for i in range(0, common):
        if new_list[i] == old_list[i]:
            continue
        return i
    return common