# encoding: utf-8
# author: Christoph Hartmann
# author: Dominik Richter

# Usage:
# describe group('root') do
#   it { should exist }
#   its('gid') { should eq 0 }
# end
#
# deprecated has matcher
# describe group('root') do
#  it { should have_gid 0 }
# end

class Group < Inspec.resource(1)
  name 'group'
  desc 'Use the group InSpec audit resource to test groups on the system.'
  example "
    describe group('root') do
      it { should exist }
      its('gid') { should eq 0 }
    end
  "

  def initialize(groupname, domain = nil)
    @group = groupname.downcase
    @domain = domain
    @domain = @domain.downcase unless @domain.nil?

    @cache = nil

    # select group manager
    @group_provider = nil
    if inspec.os.unix?
      @group_provider = UnixGroup.new(inspec)
    elsif inspec.os.windows?
      @group_provider = WindowsGroup.new(inspec)
    else
      return skip_resource 'The `group` resource is not supported on your OS yet.'
    end
  end

  # verifies if a group exists
  def exists?
    # ensure that we found one group
    !group_info.nil? && group_info.size > 0
  end

  def gid
    return nil if group_info.nil? || group_info.size == 0

    # the default case should be one group
    return group_info[0][:gid] if group_info.size == 1

    # return array if we got multiple gids
    group_info.map { |grp| grp[:gid] }
  end

  # implements rspec has matcher, to be compatible with serverspec
  def has_gid?(compare_gid)
    gid == compare_gid
  end

  def local
    return nil if group_info.nil? || group_info.size == 0

    # the default case should be one group
    return group_info[0][:local] if group_info.size == 1

    # return array if we got multiple gids
    group_info.map { |grp| grp[:local] }
  end

  def to_s
    "Group #{@group}"
  end

  private

  def group_info
    return @cache if !@cache.nil?
    @cache = @group_provider.group_info(@group, @domain) if !@group_provider.nil?
  end
end

class GroupInfo
  attr_reader :inspec
  def initialize(inspec)
    @inspec = inspec
  end
end

# implements generic unix groups via /etc/group
class UnixGroup < GroupInfo
  def group_info(group, _domain = nil)
    inspec.etc_group.where(name: group).entries.map { |grp|
      {
        name: grp['name'],
        gid: grp['gid'],
      }
    }
  end
end

class WindowsGroup < GroupInfo
  def group_info(compare_group, compare_domain = nil)
    cmd = inspec.command('Get-WmiObject Win32_Group | Select-Object -Property Caption, Domain, Name, SID, LocalAccount | ConvertTo-Json')

    # cannot rely on exit code for now, successful command returns exit code 1
    # return nil if cmd.exit_status != 0, try to parse json
    begin
      groups = JSON.parse(cmd.stdout)
    rescue JSON::ParserError => _e
      return nil
    end

    # ensure we have an array of groups
    groups = [groups] if !groups.is_a?(Array)

    # reduce list
    groups.each_with_object([]) do |grp, grp_collection|
      # map object
      grp_info = {
        name: grp['Name'],
        domain: grp['Domain'],
        caption: grp['Caption'],
        gid: nil,
        sid: grp['SID'],
        local: grp['LocalAccount'],
      }
      return grp_collection.push(grp_info) if grp_info[:name].casecmp(compare_group) == 0 && (compare_domain.nil? || grp_info[:domain].casecmp(compare_domain) == 0)
    end
  end
end