#!/usr/bin/env python
# vim: set fileencoding=utf-8 :
#
# Copyright (C) 2016 Guido Günther <agx@sigxcpu.org>,
#                    Daniel Lobato Garcia <dlobatog@redhat.com>
#
# This script 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 it.  If not, see <http://www.gnu.org/licenses/>.
#
# This is somewhat based on cobbler inventory

# Stdlib imports
# __future__ imports must occur at the beginning of file
from __future__ import print_function
try:
    # Python 2 version
    import ConfigParser
except ImportError:
    # Python 3 version
    import configparser as ConfigParser
import json
import argparse
import copy
import os
import re
import sys
from time import time, sleep
from collections import defaultdict
from distutils.version import LooseVersion, StrictVersion

# 3rd party imports
import requests
if LooseVersion(requests.__version__) < LooseVersion('1.1.0'):
    print('This script requires python-requests 1.1 as a minimum version')
    sys.exit(1)

from requests.auth import HTTPBasicAuth

from ansible.module_utils._text import to_text


def json_format_dict(data, pretty=False):
    """Converts a dict to a JSON object and dumps it as a formatted string"""

    if pretty:
        return json.dumps(data, sort_keys=True, indent=2)
    else:
        return json.dumps(data)


class ForemanInventory(object):

    def __init__(self):
        self.inventory = defaultdict(list)  # A list of groups and the hosts in that group
        self.cache = dict()   # Details about hosts in the inventory
        self.params = dict()  # Params of each host
        self.facts = dict()   # Facts of each host
        self.hostgroups = dict()  # host groups
        self.hostcollections = dict()  # host collections
        self.session = None   # Requests session
        self.config_paths = [
            "/etc/ansible/foreman.ini",
            os.path.dirname(os.path.realpath(__file__)) + '/foreman.ini',
        ]
        env_value = os.environ.get('FOREMAN_INI_PATH')
        if env_value is not None:
            self.config_paths.append(os.path.expanduser(os.path.expandvars(env_value)))

    def read_settings(self):
        """Reads the settings from the foreman.ini file"""

        config = ConfigParser.SafeConfigParser()
        config.read(self.config_paths)

        # Foreman API related
        try:
            self.foreman_url = config.get('foreman', 'url')
            self.foreman_user = config.get('foreman', 'user')
            self.foreman_pw = config.get('foreman', 'password', raw=True)
            self.foreman_ssl_verify = config.getboolean('foreman', 'ssl_verify')
        except (ConfigParser.NoOptionError, ConfigParser.NoSectionError) as e:
            print("Error parsing configuration: %s" % e, file=sys.stderr)
            return False

        # Inventory Report Related
        try:
            self.foreman_use_reports_api = config.getboolean('foreman', 'use_reports_api')
        except (ConfigParser.NoOptionError, ConfigParser.NoSectionError):
            self.foreman_use_reports_api = True

        try:
            self.want_organization = config.getboolean('report', 'want_organization')
        except (ConfigParser.NoOptionError, ConfigParser.NoSectionError):
            self.want_organization = True

        try:
            self.want_location = config.getboolean('report', 'want_location')
        except (ConfigParser.NoOptionError, ConfigParser.NoSectionError):
            self.want_location = True

        try:
            self.want_IPv4 = config.getboolean('report', 'want_ipv4')
        except (ConfigParser.NoOptionError, ConfigParser.NoSectionError):
            self.want_IPv4 = True

        try:
            self.want_IPv6 = config.getboolean('report', 'want_ipv6')
        except (ConfigParser.NoOptionError, ConfigParser.NoSectionError):
            self.want_IPv6 = False

        try:
            self.want_host_group = config.getboolean('report', 'want_host_group')
        except (ConfigParser.NoOptionError, ConfigParser.NoSectionError):
            self.want_host_group = True

        try:
            self.want_host_params = config.getboolean('report', 'want_host_params')
        except (ConfigParser.NoOptionError, ConfigParser.NoSectionError):
            self.want_host_params = False

        try:
            self.want_subnet = config.getboolean('report', 'want_subnet')
        except (ConfigParser.NoOptionError, ConfigParser.NoSectionError):
            self.want_subnet = True

        try:
            self.want_subnet_v6 = config.getboolean('report', 'want_subnet_v6')
        except (ConfigParser.NoOptionError, ConfigParser.NoSectionError):
            self.want_subnet_v6 = False

        try:
            self.want_smart_proxies = config.getboolean('report', 'want_smart_proxies')
        except (ConfigParser.NoOptionError, ConfigParser.NoSectionError):
            self.want_smart_proxies = True

        try:
            self.want_content_facet_attributes = config.getboolean('report', 'want_content_facet_attributes')
        except (ConfigParser.NoOptionError, ConfigParser.NoSectionError):
            self.want_content_facet_attributes = False

        try:
            self.report_want_facts = config.getboolean('report', 'want_facts')
        except (ConfigParser.NoOptionError, ConfigParser.NoSectionError):
            self.report_want_facts = True

        try:
            self.poll_interval = config.getint('report', 'poll_interval')
        except (ConfigParser.NoOptionError, ConfigParser.NoSectionError):
            self.poll_interval = 10

        # Ansible related
        try:
            group_patterns = config.get('ansible', 'group_patterns')
        except (ConfigParser.NoOptionError, ConfigParser.NoSectionError):
            group_patterns = "[]"

        self.group_patterns = json.loads(group_patterns)

        try:
            self.group_prefix = config.get('ansible', 'group_prefix')
        except (ConfigParser.NoOptionError, ConfigParser.NoSectionError):
            self.group_prefix = "foreman_"

        try:
            self.want_facts = config.getboolean('ansible', 'want_facts')
        except (ConfigParser.NoOptionError, ConfigParser.NoSectionError):
            self.want_facts = True

        self.want_facts = self.want_facts and self.report_want_facts

        try:
            self.want_hostcollections = config.getboolean('ansible', 'want_hostcollections')
        except (ConfigParser.NoOptionError, ConfigParser.NoSectionError):
            self.want_hostcollections = False

        try:
            self.want_ansible_ssh_host = config.getboolean('ansible', 'want_ansible_ssh_host')
        except (ConfigParser.NoOptionError, ConfigParser.NoSectionError):
            self.want_ansible_ssh_host = False

        # Do we want parameters to be interpreted if possible as JSON? (no by default)
        try:
            self.rich_params = config.getboolean('ansible', 'rich_params')
        except (ConfigParser.NoOptionError, ConfigParser.NoSectionError):
            self.rich_params = False

        try:
            self.host_filters = config.get('foreman', 'host_filters')
        except (ConfigParser.NoOptionError, ConfigParser.NoSectionError):
            self.host_filters = None

        # Cache related
        try:
            cache_path = os.path.expanduser(config.get('cache', 'path'))
        except (ConfigParser.NoOptionError, ConfigParser.NoSectionError):
            cache_path = '.'
        (script, ext) = os.path.splitext(os.path.basename(__file__))
        self.cache_path_cache = cache_path + "/%s.cache" % script
        self.cache_path_inventory = cache_path + "/%s.index" % script
        self.cache_path_params = cache_path + "/%s.params" % script
        self.cache_path_facts = cache_path + "/%s.facts" % script
        self.cache_path_hostcollections = cache_path + "/%s.hostcollections" % script
        try:
            self.cache_max_age = config.getint('cache', 'max_age')
        except (ConfigParser.NoOptionError, ConfigParser.NoSectionError):
            self.cache_max_age = 60
        try:
            self.scan_new_hosts = config.getboolean('cache', 'scan_new_hosts')
        except (ConfigParser.NoOptionError, ConfigParser.NoSectionError):
            self.scan_new_hosts = False

        return True

    def parse_cli_args(self):
        """Command line argument processing"""

        parser = argparse.ArgumentParser(description='Produce an Ansible Inventory file based on foreman')
        parser.add_argument('--list', action='store_true', default=True, help='List instances (default: True)')
        parser.add_argument('--host', action='store', help='Get all the variables about a specific instance')
        parser.add_argument('--refresh-cache', action='store_true', default=False,
                            help='Force refresh of cache by making API requests to foreman (default: False - use cache files)')
        self.args = parser.parse_args()

    def _get_session(self):
        if not self.session:
            self.session = requests.session()
            self.session.auth = HTTPBasicAuth(self.foreman_user, self.foreman_pw)
            self.session.verify = self.foreman_ssl_verify
        return self.session

    def _get_json(self, url, ignore_errors=None, params=None):
        if params is None:
            params = {}
        params['per_page'] = 250

        page = 1
        results = []
        s = self._get_session()
        while True:
            params['page'] = page
            ret = s.get(url, params=params)
            if ignore_errors and ret.status_code in ignore_errors:
                break
            ret.raise_for_status()
            json = ret.json()
            # /hosts/:id has not results key
            if 'results' not in json:
                return json
            # Facts are returned as dict in results not list
            if isinstance(json['results'], dict):
                return json['results']
            # List of all hosts is returned paginaged
            results = results + json['results']
            if len(results) >= json['subtotal']:
                break
            page += 1
            if len(json['results']) == 0:
                print("Did not make any progress during loop. "
                      "expected %d got %d" % (json['total'], len(results)),
                      file=sys.stderr)
                break
        return results

    def _use_inventory_report(self):
        if not self.foreman_use_reports_api:
            return False
        status_url = "%s/api/v2/status" % self.foreman_url
        result = self._get_json(status_url)
        foreman_version = (LooseVersion(result.get('version')) >= LooseVersion('1.24.0'))
        return foreman_version

    def _fetch_params(self):
        options, params = ("no", "yes"), dict()
        params["Organization"] = options[self.want_organization]
        params["Location"] = options[self.want_location]
        params["IPv4"] = options[self.want_IPv4]
        params["IPv6"] = options[self.want_IPv6]
        params["Facts"] = options[self.want_facts]
        params["Host Group"] = options[self.want_host_group]
        params["Host Collections"] = options[self.want_hostcollections]
        params["Subnet"] = options[self.want_subnet]
        params["Subnet v6"] = options[self.want_subnet_v6]
        params["Smart Proxies"] = options[self.want_smart_proxies]
        params["Content Attributes"] = options[self.want_content_facet_attributes]
        params["Host Parameters"] = options[self.want_host_params]
        if self.host_filters:
            params["Hosts"] = self.host_filters
        return params

    def _post_request(self):
        url = "%s/ansible/api/v2/ansible_inventories/schedule" % self.foreman_url
        session = self._get_session()
        params = {'input_values': self._fetch_params()}
        ret = session.post(url, json=params)
        if not ret:
            raise Exception("Error scheduling inventory report on foreman. Please check foreman logs!")
        url = "{0}/{1}".format(self.foreman_url, ret.json().get('data_url'))
        response = session.get(url)
        while response:
            if response.status_code != 204:
                break
            else:
                sleep(self.poll_interval)
                response = session.get(url)
        if not response:
            raise Exception("Error receiving inventory report from foreman. Please check foreman logs!")
        else:
            return response.json()

    def _get_hosts(self):
        url = "%s/api/v2/hosts" % self.foreman_url

        params = {}
        if self.host_filters:
            params['search'] = self.host_filters

        return self._get_json(url, params=params)

    def _get_host_data_by_id(self, hid):
        url = "%s/api/v2/hosts/%s" % (self.foreman_url, hid)
        return self._get_json(url)

    def _get_facts_by_id(self, hid):
        url = "%s/api/v2/hosts/%s/facts" % (self.foreman_url, hid)
        return self._get_json(url)

    def _resolve_params(self, host_params):
        """Convert host params to dict"""
        params = {}

        for param in host_params:
            name = param['name']
            if self.rich_params:
                try:
                    params[name] = json.loads(param['value'])
                except ValueError:
                    params[name] = param['value']
            else:
                params[name] = param['value']

        return params

    def _get_facts(self, host):
        """Fetch all host facts of the host"""
        if not self.want_facts:
            return {}

        ret = self._get_facts_by_id(host['id'])
        if len(ret.values()) == 0:
            facts = {}
        elif len(ret.values()) == 1:
            facts = list(ret.values())[0]
        else:
            raise ValueError("More than one set of facts returned for '%s'" % host)
        return facts

    def write_to_cache(self, data, filename):
        """Write data in JSON format to a file"""
        json_data = json_format_dict(data, True)
        cache = open(filename, 'w')
        cache.write(json_data)
        cache.close()

    def _write_cache(self):
        self.write_to_cache(self.cache, self.cache_path_cache)
        self.write_to_cache(self.inventory, self.cache_path_inventory)
        self.write_to_cache(self.params, self.cache_path_params)
        self.write_to_cache(self.facts, self.cache_path_facts)
        self.write_to_cache(self.hostcollections, self.cache_path_hostcollections)

    def to_safe(self, word):
        '''Converts 'bad' characters in a string to underscores
        so they can be used as Ansible groups

        >>> ForemanInventory.to_safe("foo-bar baz")
        'foo_barbaz'
        '''
        regex = r"[^A-Za-z0-9\_]"
        return re.sub(regex, "_", word.replace(" ", ""))

    def update_cache(self, scan_only_new_hosts=False):
        """Make calls to foreman and save the output in a cache"""
        use_inventory_report = self._use_inventory_report()
        if use_inventory_report:
            self._update_cache_inventory(scan_only_new_hosts)
        else:
            self._update_cache_host_api(scan_only_new_hosts)

    def _update_cache_inventory(self, scan_only_new_hosts):
        self.groups = dict()
        self.hosts = dict()
        try:
            inventory_report_response = self._post_request()
        except Exception:
            self._update_cache_host_api(scan_only_new_hosts)
            return
        host_data = json.loads(inventory_report_response)
        for host in host_data:
            if not(host) or (host["name"] in self.cache.keys() and scan_only_new_hosts):
                continue
            dns_name = host['name']

            host_params = host.pop('host_parameters', {})
            fact_list = host.pop('facts', {})
            content_facet_attributes = host.get('content_attributes', {}) or {}

            # Create ansible groups for hostgroup
            group = 'host_group'
            val = host.get(group)
            if val:
                safe_key = self.to_safe('%s%s_%s' % (
                    to_text(self.group_prefix),
                    group,
                    to_text(val).lower()
                ))
                self.inventory[safe_key].append(dns_name)

            # Create ansible groups for environment, location and organization
            for group in ['environment', 'location', 'organization']:
                val = host.get('%s' % group)
                if val:
                    safe_key = self.to_safe('%s%s_%s' % (
                        to_text(self.group_prefix),
                        group,
                        to_text(val).lower()
                    ))
                    self.inventory[safe_key].append(dns_name)

            for group in ['lifecycle_environment', 'content_view']:
                val = content_facet_attributes.get('%s_name' % group)
                if val:
                    safe_key = self.to_safe('%s%s_%s' % (
                        to_text(self.group_prefix),
                        group,
                        to_text(val).lower()
                    ))
                    self.inventory[safe_key].append(dns_name)

            params = host_params

            # Ansible groups by parameters in host groups and Foreman host
            # attributes.
            groupby = dict()
            for k, v in params.items():
                groupby[k] = self.to_safe(to_text(v))

            # The name of the ansible groups is given by group_patterns:
            for pattern in self.group_patterns:
                try:
                    key = pattern.format(**groupby)
                    self.inventory[key].append(dns_name)
                except KeyError:
                    pass  # Host not part of this group

            if self.want_hostcollections:
                hostcollections = host.get('host_collections')

                if hostcollections:
                    # Create Ansible groups for host collections
                    for hostcollection in hostcollections:
                        safe_key = self.to_safe('%shostcollection_%s' % (self.group_prefix, hostcollection.lower()))
                        self.inventory[safe_key].append(dns_name)

                self.hostcollections[dns_name] = hostcollections

            self.cache[dns_name] = host
            self.params[dns_name] = params
            self.facts[dns_name] = fact_list
            self.inventory['all'].append(dns_name)
        self._write_cache()

    def _update_cache_host_api(self, scan_only_new_hosts):
        """Make calls to foreman and save the output in a cache"""

        self.groups = dict()
        self.hosts = dict()

        for host in self._get_hosts():
            if host['name'] in self.cache.keys() and scan_only_new_hosts:
                continue
            dns_name = host['name']

            host_data = self._get_host_data_by_id(host['id'])
            host_params = host_data.get('all_parameters', {})

            # Create ansible groups for hostgroup
            group = 'hostgroup'
            val = host.get('%s_title' % group) or host.get('%s_name' % group)
            if val:
                safe_key = self.to_safe('%s%s_%s' % (
                    to_text(self.group_prefix),
                    group,
                    to_text(val).lower()
                ))
                self.inventory[safe_key].append(dns_name)

            # Create ansible groups for environment, location and organization
            for group in ['environment', 'location', 'organization']:
                val = host.get('%s_name' % group)
                if val:
                    safe_key = self.to_safe('%s%s_%s' % (
                        to_text(self.group_prefix),
                        group,
                        to_text(val).lower()
                    ))
                    self.inventory[safe_key].append(dns_name)

            for group in ['lifecycle_environment', 'content_view']:
                val = host.get('content_facet_attributes', {}).get('%s_name' % group)
                if val:
                    safe_key = self.to_safe('%s%s_%s' % (
                        to_text(self.group_prefix),
                        group,
                        to_text(val).lower()
                    ))
                    self.inventory[safe_key].append(dns_name)

            params = self._resolve_params(host_params)

            # Ansible groups by parameters in host groups and Foreman host
            # attributes.
            groupby = dict()
            for k, v in params.items():
                groupby[k] = self.to_safe(to_text(v))

            # The name of the ansible groups is given by group_patterns:
            for pattern in self.group_patterns:
                try:
                    key = pattern.format(**groupby)
                    self.inventory[key].append(dns_name)
                except KeyError:
                    pass  # Host not part of this group

            if self.want_hostcollections:
                hostcollections = host_data.get('host_collections')

                if hostcollections:
                    # Create Ansible groups for host collections
                    for hostcollection in hostcollections:
                        safe_key = self.to_safe('%shostcollection_%s' % (self.group_prefix, hostcollection['name'].lower()))
                        self.inventory[safe_key].append(dns_name)

                self.hostcollections[dns_name] = hostcollections

            self.cache[dns_name] = host
            self.params[dns_name] = params
            self.facts[dns_name] = self._get_facts(host)
            self.inventory['all'].append(dns_name)
        self._write_cache()

    def is_cache_valid(self):
        """Determines if the cache is still valid"""
        if os.path.isfile(self.cache_path_cache):
            mod_time = os.path.getmtime(self.cache_path_cache)
            current_time = time()
            if (mod_time + self.cache_max_age) > current_time:
                if (os.path.isfile(self.cache_path_inventory) and
                    os.path.isfile(self.cache_path_params) and
                        os.path.isfile(self.cache_path_facts)):
                    return True
        return False

    def load_inventory_from_cache(self):
        """Read the index from the cache file sets self.index"""

        with open(self.cache_path_inventory, 'r') as fp:
            self.inventory = json.load(fp)

    def load_params_from_cache(self):
        """Read the index from the cache file sets self.index"""

        with open(self.cache_path_params, 'r') as fp:
            self.params = json.load(fp)

    def load_facts_from_cache(self):
        """Read the index from the cache file sets self.facts"""

        if not self.want_facts:
            return
        with open(self.cache_path_facts, 'r') as fp:
            self.facts = json.load(fp)

    def load_hostcollections_from_cache(self):
        """Read the index from the cache file sets self.hostcollections"""

        if not self.want_hostcollections:
            return
        with open(self.cache_path_hostcollections, 'r') as fp:
            self.hostcollections = json.load(fp)

    def load_cache_from_cache(self):
        """Read the cache from the cache file sets self.cache"""

        with open(self.cache_path_cache, 'r') as fp:
            self.cache = json.load(fp)

    def get_inventory(self):
        if self.args.refresh_cache or not self.is_cache_valid():
            self.update_cache()
        else:
            self.load_inventory_from_cache()
            self.load_params_from_cache()
            self.load_facts_from_cache()
            self.load_hostcollections_from_cache()
            self.load_cache_from_cache()
            if self.scan_new_hosts:
                self.update_cache(True)

    def get_host_info(self):
        """Get variables about a specific host"""

        if not self.cache or len(self.cache) == 0:
            # Need to load index from cache
            self.load_cache_from_cache()

        if self.args.host not in self.cache:
            # try updating the cache
            self.update_cache()

            if self.args.host not in self.cache:
                # host might not exist anymore
                return json_format_dict({}, True)

        return json_format_dict(self.cache[self.args.host], True)

    def _print_data(self):
        data_to_print = ""
        if self.args.host:
            data_to_print += self.get_host_info()
        else:
            self.inventory['_meta'] = {'hostvars': {}}
            for hostname in self.cache:
                self.inventory['_meta']['hostvars'][hostname] = {
                    'foreman': self.cache[hostname],
                    'foreman_params': self.params[hostname],
                }
                if self.want_ansible_ssh_host and 'ip' in self.cache[hostname]:
                    self.inventory['_meta']['hostvars'][hostname]['ansible_ssh_host'] = self.cache[hostname]['ip']
                if self.want_facts:
                    self.inventory['_meta']['hostvars'][hostname]['foreman_facts'] = self.facts[hostname]

            data_to_print += json_format_dict(self.inventory, True)

        print(data_to_print)

    def run(self):
        # Read settings and parse CLI arguments
        if not self.read_settings():
            return False
        self.parse_cli_args()
        self.get_inventory()
        self._print_data()
        return True


if __name__ == '__main__':
    sys.exit(not ForemanInventory().run())