import logging
import subprocess
import re
import os
import configparser

logger = logging.getLogger ('boottools')

def run (args):
    cp = subprocess.run (args, text=True, capture_output=True)
    if cp.returncode:
        logger.error ('command "{}" failed with rc "{}"'.format (' '.join(args), cp.returncode))

        logger.error ('stdout follows:')
        for i in cp.stdout.strip().split('\n'): logger.error ('  ' + i)

        logger.error ('stderr follows:')
        for i in cp.stderr.strip().split('\n'): logger.error ('  ' + i)

        raise Exception ('command "{}" failed with rc "{}"'.format (' '.join(args), cp.returncode))
    stdout = cp.stdout.strip()
    stderr = cp.stderr.strip()
    return stdout, stderr

def grep (regex, file):
    with open (file, 'r') as f:
        for l in f:
            if (re.findall (regex, l)): return 1
        return 0

def is_mounted (mntpt):
    return grep (mntpt, '/proc/mounts')

def mount (dev, mntpt, opts=[]):
    if not is_mounted (mntpt):
        run (['mount', dev, mntpt] + opts)

def umount (mntpt):
    if (is_mounted (mntpt)):
        run (['umount', mntpt])

def read_config (fn):
    if not os.path.exists (fn):
        print (f'configuration file "{fn}" not found')
        return
    config = configparser.ConfigParser (comment_prefixes='#', inline_comment_prefixes='#')
    config.read (fn)
    return config

def write_md5 (fn):
    md5, _ = run (['md5sum', fn])
    md5, rest = md5.split (' ', 1)
    with open (f'{fn}.sum', 'w') as fd:
        fd.write (md5 + '\n')