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

# Usage:
# describe interface('eth0') do
#   it { should exist }
#   it { should be_up }
#   its(:speed) { should eq 1000 }
# end

require 'utils/convert'

class NetworkInterface < Inspec.resource(1)
  name 'interface'

  def initialize(iface)
    @iface = iface

    @interface_provider = nil
    if inspec.os.linux?
      @interface_provider = LinuxInterface.new(inspec)
    elsif inspec.os.windows?
      @interface_provider = WindowsInterface.new(inspec)
    else
      return skip_resource 'The `interface` resource is not supported on your OS yet.'
    end
  end

  def exists?
    !interface_info.nil? && !interface_info[:name].nil?
  end

  def up?
    interface_info.nil? ? false : interface_info[:up]
  end

  # returns link speed in Mbits/sec
  def speed
    interface_info.nil? ? nil : interface_info[:speed]
  end

  def to_s
    "Interface #{@iface}"
  end

  private

  def interface_info
    return @cache if defined?(@cache)
    @cache = @interface_provider.interface_info(@iface) if !@interface_provider.nil?
  end
end

class InterfaceInfo
  include Converter
  attr_reader :inspec
  def initialize(inspec)
    @inspec = inspec
  end
end

class LinuxInterface < InterfaceInfo
  def interface_info(iface)
    # will return "[mtu]\n1500\n[type]\n1"
    cmd = inspec.command("find /sys/class/net/#{iface}/ -type f -maxdepth 1 -exec sh -c 'echo \"[$(basename {})]\"; cat {} || echo -n' \\;")
    return nil if cmd.exit_status.to_i != 0

    # parse values, we only recieve values, therefore we threat them as keys
    params = SimpleConfig.new(cmd.stdout.chomp).params

    # abort if we got an empty result-set
    return nil if params.empty?

    # parse state
    state = false
    if params.key?('operstate')
      operstate, _value = params['operstate'].first
      state = operstate == 'up'
    end

    # parse speed
    speed = nil
    if params.key?('speed')
      speed, _value = params['speed'].first
      speed = convert_to_i(speed)
    end

    {
      name: iface,
      up: state,
      speed: speed,
    }
  end
end

class WindowsInterface < InterfaceInfo
  def interface_info(iface)
    # gather all network interfaces
    cmd = inspec.command('Get-NetAdapter | Select-Object -Property Name, InterfaceDescription, Status, State, MacAddress, LinkSpeed, ReceiveLinkSpeed, TransmitLinkSpeed, Virtual | ConvertTo-Json')

    # filter network interface
    begin
      net_adapter = JSON.parse(cmd.stdout)
    rescue JSON::ParserError => _e
      return nil
    end

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

    # select the requested interface
    adapters = net_adapter.each_with_object([]) do |adapter, adapter_collection|
      # map object
      info = {
        name: adapter['Name'],
        up: adapter['State'] == 2,
        speed: adapter['ReceiveLinkSpeed'] / 1000,
      }
      adapter_collection.push(info) if info[:name].casecmp(iface) == 0
    end

    return nil if adapters.size == 0
    warn "[Possible Error] detected multiple network interfaces with the name #{iface}" if adapters.size > 1
    adapters[0]
  end
end