# Copyright (c) 2018 Red Hat, Inc.
# GNU General Public License v3.0+ (see COPYING.GPL or https://www.gnu.org/licenses/gpl-3.0.txt)

import fnmatch
import os
import re

from ansible.parsing.yaml.objects import AnsibleMapping
from ansible.plugins.inventory import BaseFileInventoryPlugin

DOCUMENTATION = '''
    inventory: yamlgroup
    version_added: "2.8"
    short_description: Simple group manipulation for existing hosts
    description:
        - YAML based inventory that only manipulates group membership for
          existing hosts.
    options:
      yaml_extensions:
        description: list of 'valid' extensions for files containing YAML
        type: list
        default: ['.yaml', '.yml', '.json']
        env:
          - name: ANSIBLE_YAML_FILENAME_EXT
          - name: ANSIBLE_INVENTORY_PLUGIN_EXTS
        ini:
          - key: yaml_valid_extensions
            section: defaults
          - section: inventory_plugin_yaml
            key: yaml_valid_extensions
      groups:
        description: |
          dict with group name as key. If the list item starts with a
          ^ it will be considered a regex pattern (i.e. passed to
          re.match), otherwise it is considered a fnmatch pattern.
        type: dict
        default: {}
'''
EXAMPLES = '''
plugin: yamlgroup
groups:
  amazing:
    - fullhost.example.com
    - amazing*
    - ^regex.*pattern
'''


class InventoryModule(BaseFileInventoryPlugin):

    NAME = 'yamlgroup'

    def verify_file(self, path):

        valid = False
        if super(InventoryModule, self).verify_file(path):
            file_name, ext = os.path.splitext(path)
            if ext in self.get_option('yaml_extensions'):
                valid = True
        return valid

    def parse(self, inventory, loader, path, cache=True):
        ''' parses the inventory file '''

        super(InventoryModule, self).parse(inventory, loader, path)

        self._read_config_data(path)

        groups = self.get_option('groups')

        found_groups = {}

        for group, hosts in groups.items():
            if not isinstance(hosts, list):
                hosts = [hosts]
            for candidate in hosts:
                # If someone accidentally puts a dict into the list of hosts,
                # the errors are ... obscure at best and the entire inventory
                # will fail. Grab the dict key in those cases rather than
                # failing.
                if isinstance(candidate, AnsibleMapping):
                    candidate = list(candidate.keys())[0]

                # Starts with ^ means it is already a regex.
                # Otherwise it's a fnmatch compatible string; use it's
                # helper to turn that into a regex so we have a common
                # match below.
                if not candidate.startswith('^'):
                    candidate = fnmatch.translate(candidate)

                for existing in self.inventory.hosts.values():
                    if re.match(candidate, existing.get_name()):
                        found_groups.setdefault(group, [])
                        found_groups[group].append(existing)

        for group, hosts in found_groups.items():
            self.inventory.add_group(group)
            for host in hosts:
                self.inventory.add_child(group, host.get_name())