# vi: ts=4 expandtab
#
#    Copyright (C) 2009-2010 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
import cloudinit.SshUtil as sshutil
import os
import glob
import subprocess

DISABLE_ROOT_OPTS = "no-port-forwarding,no-agent-forwarding," \
"no-X11-forwarding,command=\"echo \'Please login as the user \\\"$USER\\\" " \
"rather than the user \\\"root\\\".\';echo;sleep 10\""


def handle(_name, cfg, cloud, log, _args):

    # remove the static keys from the pristine image
    if cfg.get("ssh_deletekeys", True):
        for f in glob.glob("/etc/ssh/ssh_host_*key*"):
            try:
                os.unlink(f)
            except:
                pass

    if "ssh_keys" in cfg:
        # if there are keys in cloud-config, use them
        key2file = {
            "rsa_private": ("/etc/ssh/ssh_host_rsa_key", 0600),
            "rsa_public": ("/etc/ssh/ssh_host_rsa_key.pub", 0644),
            "dsa_private": ("/etc/ssh/ssh_host_dsa_key", 0600),
            "dsa_public": ("/etc/ssh/ssh_host_dsa_key.pub", 0644),
            "ecdsa_private": ("/etc/ssh/ssh_host_ecdsa_key", 0600),
            "ecdsa_public": ("/etc/ssh/ssh_host_ecdsa_key.pub", 0644),
        }

        for key, val in cfg["ssh_keys"].items():
            if key in key2file:
                util.write_file(key2file[key][0], val, key2file[key][1])

        priv2pub = {'rsa_private': 'rsa_public', 'dsa_private': 'dsa_public',
                    'ecdsa_private': 'ecdsa_public', }

        cmd = 'o=$(ssh-keygen -yf "%s") && echo "$o" root@localhost > "%s"'
        for priv, pub in priv2pub.iteritems():
            if pub in cfg['ssh_keys'] or not priv in cfg['ssh_keys']:
                continue
            pair = (key2file[priv][0], key2file[pub][0])
            subprocess.call(('sh', '-xc', cmd % pair))
            log.debug("generated %s from %s" % pair)
    else:
        # if not, generate them
        for keytype in util.get_cfg_option_list_or_str(cfg, 'ssh_genkeytypes',
                                                      ['rsa', 'dsa', 'ecdsa']):
            keyfile = '/etc/ssh/ssh_host_%s_key' % keytype
            if not os.path.exists(keyfile):
                subprocess.call(['ssh-keygen', '-t', keytype, '-N', '',
                                 '-f', keyfile])

    util.restorecon_if_possible('/etc/ssh', recursive=True)

    try:
        user = util.get_cfg_option_str(cfg, 'user')
        disable_root = util.get_cfg_option_bool(cfg, "disable_root", True)
        disable_root_opts = util.get_cfg_option_str(cfg, "disable_root_opts",
            DISABLE_ROOT_OPTS)
        keys = cloud.get_public_ssh_keys()

        if "ssh_authorized_keys" in cfg:
            cfgkeys = cfg["ssh_authorized_keys"]
            keys.extend(cfgkeys)

        apply_credentials(keys, user, disable_root, disable_root_opts, log)
    except:
        util.logexc(log)
        log.warn("applying credentials failed!\n")


def apply_credentials(keys, user, disable_root,
                      disable_root_opts=DISABLE_ROOT_OPTS, log=None):
    keys = set(keys)
    if user:
        sshutil.setup_user_keys(keys, user, '', log)

    if disable_root:
        key_prefix = disable_root_opts.replace('$USER', user)
    else:
        key_prefix = ''

    sshutil.setup_user_keys(keys, 'root', key_prefix, log)