_noteworthy = []


def noteworthy(msg):
    """
    noteworthy can be use to take note things which we may not want to
    report to the user may but be worth including in bug report
    if something goes wrong later on
    """
    _noteworthy.append(msg)

def popen(command, flag='', shell=None, input=None, timeout=None, env=None,
          stdout=PIPE, stderr=PIPE, decode='utf-8'):
    """
    popen is a wrapper helper aound subprocess.Popen
    with it default setting it will return a tuple (out, err)
    out: the output of the program run
    err: the error code returned by the program

    it can be affected by the following flags:
    shell:   do not try to auto-detect if a shell is required
             for example if a pipe (|) or redirection (>, >>) is used
    input:   data to sent to the child process via STDIN
             the data should be bytes but string will be converted
    timeout: time after which the command will be considered to have failed
    env:     mapping that defines the environment variables for the new process
    stdout:  define how the output of the program should be handled
              - PIPE (default), sends stdout to the output
              - DEVNULL, discard the output
    stderr:  define how the output of the program should be handled
              - None (default), send/merge the data to/with stderr
              - PIPE, popen will append it to output
              - STDOUT, send the data to be merged with stdout
              - DEVNULL, discard the output
    decode:  specify the expected text encoding (utf-8, ascii, ...)
             the default is explicitely utf-8 which is python's own default

    usage:
    get both stdout and stderr: popen('command', stdout=PIPE, stderr=STDOUT)
    discard stdout and get stderr: popen('command', stdout=DEVNUL, stderr=PIPE)
    """

    # airbag must be left as an import in the function as otherwise we have a
    # a circual import dependency
    from vyos import debug
    from vyos import airbag

    # log if the flag is set, otherwise log if command is set
    if not debug.enabled(flag):
        flag = 'command'

    cmd_msg = f"cmd '{command}'"
    debug.message(cmd_msg, flag)

    use_shell = shell
    stdin = None
    if shell is None:
        use_shell = False
        if ' ' in command:
            use_shell = True
        if env:
            use_shell = True

    if input:
        stdin = PIPE
        input = input.encode() if type(input) is str else input

    p = Popen(command, stdin=stdin, stdout=stdout, stderr=stderr,
              env=env, shell=use_shell)

    pipe = p.communicate(input, timeout)

    pipe_out = b''
    if stdout == PIPE:
        pipe_out = pipe[0]

    pipe_err = b''
    if stderr == PIPE:
        pipe_err = pipe[1]

    str_out = pipe_out.decode(decode).replace('\r\n', '\n').strip()
    str_err = pipe_err.decode(decode).replace('\r\n', '\n').strip()

    out_msg = f"returned (out):\n{str_out}"
    if str_out:
        debug.message(out_msg, flag)

    if str_err:
        from sys import stderr
        err_msg = f"returned (err):\n{str_err}"
        # this message will also be send to syslog via airbag
        debug.message(err_msg, flag, destination=stderr)

        # should something go wrong, report this too via airbag
        airbag.noteworthy(cmd_msg)
        airbag.noteworthy(out_msg)
        airbag.noteworthy(err_msg)

    return str_out, p.returncode