# vi: ts=4 expandtab
#
#    Copyright (C) 2011 Canonical Ltd.
#
#    Author: Scott Moser <scott.moser@canonical.com>
#
#    This program is free software: you can redistribute it and/or modify
#    it under the terms of the GNU General Public License version 3, as
#    published by the Free Software Foundation.
#
#    This program is distributed in the hope that it will be useful,
#    but WITHOUT ANY WARRANTY; without even the implied warranty of
#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#    GNU General Public License for more details.
#
#    You should have received a copy of the GNU General Public License
#    along with this program.  If not, see <http://www.gnu.org/licenses/>.
import cloudinit.util as util
from cloudinit.CloudConfig import per_always
import platform
import StringIO

frequency = per_always

def handle(name,cfg,cloud,log,args):
    if not util.get_cfg_option_bool(cfg,"manage_etc_hosts",False):
        log.debug("manage_etc_hosts is not set, checking sanity of /etc/hosts")
        with open('/etc/hosts', 'r') as etchosts:
            current_hostname = platform.node()
            hosts_line = "# Added by cloud-init\n127.0.1.1\t%s.localdomain %s\n" % (current_hostname, current_hostname)
            need_write = False
            need_change = True
            new_etchosts = StringIO.StringIO()
            for line in etchosts:
                split_line = [s.strip() for s in line.split()]
                # skip over malformed /etc/hosts entries
                if len(split_line) < 2:
                    continue
                ip, hostnames = split_line[0], split_line[1:]
                if ip == "127.0.1.1":
                    for hostname in hostnames:
                        if hostname == current_hostname:
                            need_change = False
                    if need_change == True:
                        line = hosts_line
                        need_change = False
                        need_write = True
                new_etchosts.write(line)
            etchosts.close()
            if need_change == True:
                new_etchosts.write(hosts_line)
                need_write = True
            if need_write == True:
                new_etcfile = open ('/etc/hosts','wb')
                new_etcfile.write(new_etchosts.getvalue())
                new_etcfile.close()
            new_etchosts.close()
        return

    try:
        hostname = util.get_cfg_option_str(cfg,"hostname",cloud.get_hostname())
        if not hostname:
            hostname = cloud.get_hostname()

        if not hostname:
            log.info("manage_etc_hosts was set, but no hostname found")
            return

        util.render_to_file('hosts', '/etc/hosts', { 'hostname' : hostname })

    except Exception as e:
        log.warn("failed to update /etc/hosts")
        raise