# 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

module Inspec::Resources
  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
end