#!/usr/bin/env python

# (c) 2013, Sebastien Goasguen <runseb@gmail.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/>.

######################################################################

'''
Apache Libcloud generic external inventory script
=================================

Generates inventory that Ansible can understand by making API request to
Cloud providers using the Apache libcloud library.

This script also assumes there is a libcloud.ini file alongside it

'''

import sys
import os
import argparse
import re
from time import time
import ConfigParser

from six import iteritems
from libcloud.compute.types import Provider
from libcloud.compute.providers import get_driver
import libcloud.security as sec

try:
    import json
except ImportError:
    import simplejson as json


class LibcloudInventory(object):
    def __init__(self):
        ''' Main execution path '''

        # Inventory grouped by instance IDs, tags, security groups, regions,
        # and availability zones
        self.inventory = {}

        # Index of hostname (address) to instance ID
        self.index = {}

        # Read settings and parse CLI arguments
        self.read_settings()
        self.parse_cli_args()

        # Cache
        if self.args.refresh_cache:
            self.do_api_calls_update_cache()
        elif not self.is_cache_valid():
            self.do_api_calls_update_cache()

        # Data to print
        if self.args.host:
            data_to_print = self.get_host_info()

        elif self.args.list:
            # Display list of instances for inventory
            if len(self.inventory) == 0:
                data_to_print = self.get_inventory_from_cache()
            else:
                data_to_print = self.json_format_dict(self.inventory, True)

        print(data_to_print)


    def is_cache_valid(self):
        ''' Determines if the cache files have expired, or if it 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_index):
                    return True

        return False


    def read_settings(self):
        ''' Reads the settings from the libcloud.ini file '''

        config = ConfigParser.SafeConfigParser()
        libcloud_default_ini_path = os.path.join(os.path.dirname(os.path.realpath(__file__)), 'libcloud.ini')
        libcloud_ini_path = os.environ.get('LIBCLOUD_INI_PATH', libcloud_default_ini_path)
        config.read(libcloud_ini_path)

        if not config.has_section('driver'):
            raise ValueError('libcloud.ini file must contain a [driver] section')

        if config.has_option('driver', 'provider'):
            self.provider = config.get('driver','provider')
        else:
            raise ValueError('libcloud.ini does not have a provider defined')

        if config.has_option('driver', 'key'):
            self.key = config.get('driver','key')
        else:
            raise ValueError('libcloud.ini does not have a key defined')

        if config.has_option('driver', 'secret'):
            self.secret = config.get('driver','secret')
        else:
            raise ValueError('libcloud.ini does not have a secret defined')

        if config.has_option('driver', 'host'):
            self.host = config.get('driver', 'host')
        if config.has_option('driver', 'secure'):
            self.secure = config.get('driver', 'secure')
        if config.has_option('driver', 'verify_ssl_cert'):
            self.verify_ssl_cert = config.get('driver', 'verify_ssl_cert')
        if config.has_option('driver', 'port'):
            self.port = config.get('driver', 'port')
        if config.has_option('driver', 'path'):
            self.path = config.get('driver', 'path')
        if config.has_option('driver', 'api_version'):
            self.api_version = config.get('driver', 'api_version')    

        Driver = get_driver(getattr(Provider, self.provider))

        self.conn = Driver(key=self.key, secret=self.secret, secure=self.secure,
                           host=self.host, path=self.path)

        # Cache related
        cache_path = config.get('cache', 'cache_path')
        self.cache_path_cache = cache_path + "/ansible-libcloud.cache"
        self.cache_path_index = cache_path + "/ansible-libcloud.index"
        self.cache_max_age = config.getint('cache', 'cache_max_age')
        

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

        parser = argparse.ArgumentParser(description='Produce an Ansible Inventory file based on libcloud supported providers')
        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 libcloud supported providers (default: False - use cache files)')
        self.args = parser.parse_args()


    def do_api_calls_update_cache(self):
        ''' 
        Do API calls to a location, and save data in cache files 
        '''

        self.get_nodes()

        self.write_to_cache(self.inventory, self.cache_path_cache)
        self.write_to_cache(self.index, self.cache_path_index)


    def get_nodes(self):
        '''
        Gets the list of all nodes
        '''

        for node in self.conn.list_nodes():
            self.add_node(node)


    def get_node(self, node_id):
        '''
        Gets details about a specific node
        '''

        return [node for node in self.conn.list_nodes() if node.id == node_id][0]


    def add_node(self, node):
        '''
        Adds a node to the inventory and index, as long as it is
        addressable 
        '''

        # Only want running instances
        if node.state != 0:
            return

        # Select the best destination address
        if not node.public_ips == []:
            dest = node.public_ips[0]
        if not dest:
            # Skip instances we cannot address (e.g. private VPC subnet)
            return

        # Add to index
        self.index[dest] = node.name

        # Inventory: Group by instance ID (always a group of 1)
        self.inventory[node.name] = [dest]
        '''
        # Inventory: Group by region
        self.push(self.inventory, region, dest)

        # Inventory: Group by availability zone
        self.push(self.inventory, node.placement, dest)

        # Inventory: Group by instance type
        self.push(self.inventory, self.to_safe('type_' + node.instance_type), dest)
        '''
        # Inventory: Group by key pair
        if node.extra['key_name']:
            self.push(self.inventory, self.to_safe('key_' + node.extra['key_name']), dest)
            
        # Inventory: Group by security group, quick thing to handle single sg
        if node.extra['security_group']:
            self.push(self.inventory, self.to_safe('sg_' + node.extra['security_group'][0]), dest)

        # Inventory: Group by tag
        if node.extra['tags']:
            for tagkey in node.extra['tags'].keys():
                self.push(self.inventory, self.to_safe('tag_' + tagkey + '_' + node.extra['tags'][tagkey]), dest)

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

        if len(self.index) == 0:
            # Need to load index from cache
            self.load_index_from_cache()

        if not self.args.host in self.index:
            # try updating the cache
            self.do_api_calls_update_cache()
            if not self.args.host in self.index:
                # host migh not exist anymore
                return self.json_format_dict({}, True)

        node_id = self.index[self.args.host]

        node = self.get_node(node_id)
        instance_vars = {}
        for key in vars(instance):
            value = getattr(instance, key)
            key = self.to_safe('ec2_' + key)

            # Handle complex types
            if type(value) in [int, bool]:
                instance_vars[key] = value
            elif type(value) in [str, unicode]:
                instance_vars[key] = value.strip()
            elif type(value) == type(None):
                instance_vars[key] = ''
            elif key == 'ec2_region':
                instance_vars[key] = value.name
            elif key == 'ec2_tags':
                for k, v in iteritems(value):
                    key = self.to_safe('ec2_tag_' + k)
                    instance_vars[key] = v
            elif key == 'ec2_groups':
                group_ids = []
                group_names = []
                for group in value:
                    group_ids.append(group.id)
                    group_names.append(group.name)
                instance_vars["ec2_security_group_ids"] = ','.join(group_ids)
                instance_vars["ec2_security_group_names"] = ','.join(group_names)
            else:
                pass
                # TODO Product codes if someone finds them useful
                #print(key)
                #print(type(value))
                #print(value)

        return self.json_format_dict(instance_vars, True)


    def push(self, my_dict, key, element):
        '''
        Pushed an element onto an array that may not have been defined in
        the dict
        '''

        if key in my_dict:
            my_dict[key].append(element);
        else:
            my_dict[key] = [element]


    def get_inventory_from_cache(self):
        '''
        Reads the inventory from the cache file and returns it as a JSON
        object
        '''

        cache = open(self.cache_path_cache, 'r')
        json_inventory = cache.read()
        return json_inventory


    def load_index_from_cache(self):
        '''
        Reads the index from the cache file sets self.index
        '''

        cache = open(self.cache_path_index, 'r')
        json_index = cache.read()
        self.index = json.loads(json_index)


    def write_to_cache(self, data, filename):
        '''
        Writes data in JSON format to a file
        '''

        json_data = self.json_format_dict(data, True)
        cache = open(filename, 'w')
        cache.write(json_data)
        cache.close()


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

        return re.sub("[^A-Za-z0-9\-]", "_", word)


    def json_format_dict(self, 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)

def main():
    LibcloudInventory()

if __name__ == '__main__':
	main()