#!/usr/bin/python
# -*- coding: utf-8 -*-

"""
Ansible module to import third party repo keys to your rpm db
(c) 2013, Héctor Acosta <hector.acosta@gazzang.com>

This file is part of Ansible

Ansible is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

Ansible 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 Ansible.  If not, see <http://www.gnu.org/licenses/>.
"""

DOCUMENTATION = '''
---
module: rpm_key
author: Hector Acosta <hector.acosta@gazzang.com>
short_description: Adds or removes a gpg key from the rpm db
description:
    - Adds or removes (rpm --import) a gpg key to your rpm database.
version_added: "1.3"
options:
    key:
      required: true
      default: null
      aliases: []
      description:
          - Key that will be modified. Can be a url, a file, or a keyid if the key already exists in the database.
    state:
      required: false
      default: "present"
      choices: [present, absent]
      description:
          - Wheather the key will be imported or removed from the rpm db.
'''

EXAMPLES = '''
# Example action to import a key from a url
- rpm_key: state=present key=http://apt.sw.be/RPM-GPG-KEY.dag.txt

# Example action to import a key from a file
- rpm_key: state=present key=/path/to/key.gpg

# Example action to ensure a key is not present in the db
- rpm_key: state=absent key=DEADB33F
'''
import syslog
import os.path
import re
import urllib2
import tempfile

# Attempt to download at most 8192 bytes.
# Should be more than enough for all keys
MAXBYTES = 8192

def is_pubkey(string):
    """Verifies if string is a pubkey"""
    pgp_regex = ".*?(-----BEGIN PGP PUBLIC KEY BLOCK-----.*?-----END PGP PUBLIC KEY BLOCK-----).*"
    return re.match(pgp_regex, string, re.DOTALL)

class RpmKey:

    def __init__(self, module):
        self.syslogging = False
        # If the key is a url, we need to check if it's present to be idempotent,
        # to do that, we need to check the keyid, which we can get from the armor.
        keyfile = None
        should_cleanup_keyfile = False
        self.module = module
        self.rpm = self.module.get_bin_path('rpm', True)
        state = module.params['state']
        key = module.params['key']

        if '://' in key:
            keyfile = self.fetch_key(key)
            keyid = self.getkeyid(keyfile)
            should_cleanup_keyfile = True
        elif self.is_keyid(key):
            keyid = key
        elif os.path.isfile(key):
            keyfile = key
            keyid = self.getkeyid(keyfile)
        else:
            self.module.fail_json(msg="Not a valid key %s" % key)
        keyid = self.normalize_keyid(keyid)

        if state == 'present':
            if self.is_key_imported(keyid):
                module.exit_json(changed=False)
            else:
                if not keyfile:
                    self.module.fail_json(msg="When importing a key, a valid file must be given")
                self.import_key(keyfile, dryrun=module.check_mode)
                if should_cleanup_keyfile:
                    self.module.cleanup(keyfile)
                module.exit_json(changed=True)
        else:
            if self.is_key_imported(keyid):
                self.drop_key(keyid, dryrun=module.check_mode)
                module.exit_json(changed=True)
            else:
                module.exit_json(changed=False)


    def fetch_key(self, url, maxbytes=MAXBYTES):
        """Downloads a key from url, returns a valid path to a gpg key"""
        try:
            fd = urllib2.urlopen(url)
            key = fd.read(maxbytes)
            if not is_pubkey(key):
                self.module.fail_json(msg="Not a public key: %s" % url)
            tmpfd, tmpname = tempfile.mkstemp()
            tmpfile = os.fdopen(tmpfd, "w+b")
            tmpfile.write(key)
            tmpfile.close()
            return tmpname
        except urllib2.URLError, e:
            self.module.fail_json(msg=str(e))

    def normalize_keyid(self, keyid):
        """Ensure a keyid doesn't have a leading 0x, has leading or trailing whitespace, and make sure is lowercase"""
        ret = keyid.strip().lower()
        if ret.startswith(('0x', '0X')):
            return ret[2:]
        else:
            return ret

    def getkeyid(self, keyfile):
        gpg = self.module.get_bin_path('gpg', True)
        stdout, stderr = self.execute_command([gpg, '--no-tty', '--batch', '--with-colons', '--fixed-list-mode', '--list-packets', keyfile])
        for line in stdout.splitlines():
            line = line.strip()
            if line.startswith('keyid:'):
                # We want just the last 8 characters of the keyid
                keyid = line.split(':')[1].strip()[8:]
                return keyid
        self.json_fail(msg="Unexpected gpg output")

    def is_keyid(self, keystr):
        """Verifies if a key, as provided by the user is a keyid"""
        return re.match('(0x)?(0-9a-f){8}', keystr, flags=re.IGNORECASE)

    def execute_command(self, cmd):
        if self.syslogging:
            syslog.openlog('ansible-%s' % os.path.basename(__file__))
            syslog.syslog(syslog.LOG_NOTICE, 'Command %s' % '|'.join(cmd))
        rc, stdout, stderr = self.module.run_command(cmd)
        if rc != 0:
            self.module.fail_json(msg=stderr)
        return stdout, stderr

    def is_key_imported(self, keyid):
        stdout, stderr = self.execute_command([self.rpm, '-q', 'gpg-pubkey'])
        for line in stdout.splitlines():
            line = line.strip()
            if not line:
                continue
            match = re.match('gpg-pubkey-([0-9a-f]+)-([0-9a-f]+)', line)
            if not match:
                self.module.fail_json(msg="rpm returned unexpected output [%s]" % line)
            else:
                if keyid == match.group(1):
                    return True
        return False

    def import_key(self, keyfile, dryrun=False):
        if not dryrun:
            self.execute_command([self.rpm, '--import', keyfile])

    def drop_key(self, key, dryrun=False):
        if not dryrun:
            self.execute_command([self.rpm, '--erase', '--allmatches', "gpg-pubkey-%s" % key])


def main():
    module = AnsibleModule(
            argument_spec = dict(
                state=dict(default='present', choices=['present', 'absent'], type='str'),
                key=dict(required=True, type='str')
                ),
            supports_check_mode=True
            )

    RpmKey(module)



# import module snippets
from ansible.module_utils.basic import *
main()
