# encoding: utf-8
# copyright: 2015, Vulcano Security GmbH
# author: Christoph Hartmann
# author: Dominik Richter
# license: All rights reserved

# The file format consists of
# - group name
# - password - group's encrypted password
# - gid - group's decimal ID
# - member list - group members, comma seperated list
#
# Usage:
# describe etc_group do
#   its('gids') { should_not contain_duplicates }
#   its('groups') { should include 'my_user' }
#   its('users') { should include 'my_user' }
# end
#
# describe etc_group.where(name: 'my_group') do
#   its('users') { should include 'my_user' }
# end

require 'utils/convert'
require 'utils/parser'

class EtcGroup < Inspec.resource(1)
  include Converter
  include CommentParser

  name 'etc_group'
  desc 'Use the etc_group InSpec audit resource to test groups that are defined on Linux and UNIX platforms. The /etc/group file stores details about each group---group name, password, group identifier, along with a comma-separate list of users that belong to the group.'
  example "
    describe etc_group do
      its('gids') { should_not contain_duplicates }
      its('groups') { should include 'my_user' }
      its('users') { should include 'my_user' }
    end
  "

  attr_accessor :gid, :entries
  def initialize(path = nil)
    @path = path || '/etc/group'
    @entries = parse_group(@path)

    # skip resource if it is not supported on current OS
    return skip_resource 'The `etc_group` resource is not supported on your OS.' \
    unless %w{ubuntu debian redhat fedora centos arch darwin freebsd wrlinux}.include?(inspec.os[:family])
  end

  def groups(filter = nil)
    entries = filter || @entries
    entries.map { |x| x['name'] } if !entries.nil?
  end

  def gids(filter = nil)
    entries = filter || @entries
    entries.map { |x| x['gid'] } if !entries.nil?
  end

  def users(filter = nil)
    entries = filter || @entries
    return nil if entries.nil?
    # filter the user entry
    res = entries.map { |x|
      x['members'].split(',') if !x.nil? && !x['members'].nil?
    }.flatten
    # filter nil elements
    res.reject { |x| x.nil? || x.empty? }
  end

  def where(conditions = {})
    return if conditions.empty?
    fields = {
      name: 'name',
      group_name: 'name',
      password: 'password',
      gid: 'gid',
      group_id: 'gid',
      users: 'members',
      members: 'members',
    }
    res = entries

    conditions.each do |k, v|
      idx = fields[k.to_sym]
      next if idx.nil?
      res = res.select { |x| x[idx] == v.to_s }
    end

    EtcGroupView.new(self, res)
  end

  def to_s
    '/etc/group'
  end

  private

  def parse_group(path)
    @content = inspec.file(path).content
    if @content.nil?
      skip_resource "Can't access group file in #{path}"
      return []
    end
    # iterate over each line and filter comments
    @content.split("\n").each_with_object([]) do |line, lines|
      grp_info = parse_group_line(line)
      lines.push(grp_info) if !grp_info.nil? && grp_info.size > 0
    end
  end

  def parse_group_line(line)
    opts = {
      comment_char: '#',
      standalone_comments: false,
    }
    line, _idx_nl = parse_comment_line(line, opts)
    x = line.split(':')
    # abort if we have an empty or comment line
    return nil if x.size == 0
    # map data
    {
      'name' => x.at(0), # Name of the group.
      'password' => x.at(1), # Group's encrypted password.
      'gid' => convert_to_i(x.at(2)), # The group's decimal ID.
      'members' => x.at(3), # Group members.
    }
  end
end

# object that hold a specifc view on etc group
class EtcGroupView
  def initialize(parent, filter)
    @parent = parent
    @filter = filter
  end

  # returns the group object
  def entries
    @filter
  end

  # only returns group name
  def groups
    @parent.groups(@filter)
  end

  # only return gids
  def gids
    @parent.gids(@filter)
  end

  # only returns users
  def users
    @parent.users(@filter)
  end
end