#! /usr/bin/env python
"""
Utility functions for P4GF that are Python 2.6 compatible, for use by
the OVA management scripts. All other users should import p4gf_util.
"""

import os
import socket
import sys
import p4gf_const

Hostname = None
ServerID = None

                        # Localization/translation support.
                        # Don't let unwanted Python 3.3 code in p4gf_l10n prevent
                        # this script from running in 2.6.
try:
    from p4gf_l10n import _, NTR
except ImportError:
    def NTR(x):         # pylint: disable=invalid-name
        """No-TRanslate: Localization marker for string constants."""
        return x
    _ = NTR


def get_hostname():
    """Return the short name of the machine the Python interpreter is running on."""
    global Hostname
    if Hostname is None:
        Hostname = socket.gethostname()
        dot = Hostname.find('.')
        if dot > 0:
            Hostname = Hostname[:dot]
    return Hostname


def server_id_file_path():
    """Return the path to P4GF_HOME/server-id."""
    return os.path.join(p4gf_const.P4GF_HOME, p4gf_const.P4GF_ID_FILE)


def read_server_id_from_file():
    """If there is a P4GF_HOME/server_id file, return the ID from that.

    If not, return None.
    """
    path = server_id_file_path()
    if os.path.exists(path):
        with open(path, 'r') as f:
            words = f.read().split()
            if words:
                return words[0]
    return None


def get_server_id():
    """If there is a P4GF_HOME/server-id file, return the ID from that file.

    If not, return raise an exception.
    """
    global ServerID
    if ServerID is None:
        ServerID = read_server_id_from_file()
        if not ServerID:
            raise RuntimeError(_('server-id not set. Run configure-git-fusion.sh and try again.'))
    return ServerID


def get_object_client_name():
    """Produce the name of the host-specific object client for the Git Fusion depot."""
    return p4gf_const.P4GF_OBJECT_CLIENT.format(server_id=get_server_id())


def get_12_2_object_client_name():
    """Produce the name of the host-specific object client for the Git Fusion depot."""
    return p4gf_const.P4GF_OBJECT_CLIENT_12_2.format(hostname=get_hostname())


def has_server_id_or_exit(log=None):
    """Check if the server-id file is present, exiting if not."""
    if read_server_id_from_file() is None:
        formed = _("Git Fusion is missing '{0}' file '{1}'.").format(
            p4gf_const.P4GF_ID_FILE, server_id_file_path())
        sys.stderr.write(formed + _(' Please contact your administrator.\n'))
        if log is not None:
            log.error(formed + _(' Please contact your administrator.\n'))
        sys.exit(os.EX_SOFTWARE)