require 'log4r'
require 'rexml/document'

module VagrantPlugins
  module ProviderLibvirt
    module Action
      # Just start the domain.
      class StartDomain
        def initialize(app, env)
          @logger = Log4r::Logger.new("vagrant_libvirt::action::start_domain")
          @app = app
        end

        def call(env)
          env[:ui].info(I18n.t("vagrant_libvirt.starting_domain"))

          domain = env[:machine].provider.driver.connection.servers.get(env[:machine].id.to_s)
          raise Errors::NoDomainError if domain == nil
          config = env[:machine].provider_config

          begin
            # update domain settings on change.

            libvirt_domain =  env[:machine].provider.driver.connection.client.lookup_domain_by_uuid(env[:machine].id)

            if config.memory*1024 != libvirt_domain.max_memory
              libvirt_domain.max_memory = config.memory*1024
              libvirt_domain.memory = libvirt_domain.max_memory
            end
            begin
              # XML definition manipulation
              descr = libvirt_domain.xml_desc(1)
              xml_descr = REXML::Document.new descr
              descr_changed = false

              # additional disk bus
              config.disks.each {|disk|
                device = disk[:device]
                bus = disk[:bus]
                REXML::XPath.each(xml_descr,'/domain/devices/disk[@device="disk"]/target[@dev="'+device+'"]') {|disk_target|
                  if disk_target.attributes['bus'] != bus
                    descr_changed = true
                    disk_target.attributes['bus'] = bus
                    disk_target.parent.delete_element("#{disk_target.parent.xpath}/address")
                  end
                }
              }

              # disk_bus
              REXML::XPath.each(xml_descr,'/domain/devices/disk[@device="disk"]/target[@dev="vda"]') {|disk_target|
                if disk_target.attributes['bus'] != config.disk_bus
                  descr_changed = true
                  disk_target.attributes['bus'] = config.disk_bus
                  disk_target.parent.delete_element("#{disk_target.parent.xpath}/address")
                end
              }

              # Iterface type
              REXML::XPath.each(xml_descr,'/domain/devices/interface/model') {|iface_model|
                if iface_model.attributes['type'] != config.nic_model_type
                  descr_changed = true
                  iface_model.attributes['type'] = config.nic_model_type
                end
              }

              # vCpu count
              if config.cpus.to_i != libvirt_domain.vcpus.length
                descr_changed = true
                REXML::XPath.first(xml_descr,'/domain/vcpu').text = config.cpus
              end

              # cpu_mode
              cpu = REXML::XPath.first(xml_descr,'/domain/cpu')
              if cpu.nil?
                descr_changed = true
                cpu = REXML::Element.new('cpu', REXML::XPath.first(xml_descr,'/domain'))
                cpu.attributes['mode'] = config.cpu_mode
              else
                if cpu.attributes['mode'] != config.cpu_mode
                  descr_changed = true
                  cpu.attributes['mode'] = config.cpu_mode
                end
              end

              if config.cpu_mode != 'host-passthrough'
                cpu_model = REXML::XPath.first(xml_descr,'/domain/cpu/model')
                if cpu_model.nil?
                  descr_changed = true
                  cpu_model = REXML::Element.new('model', REXML::XPath.first(xml_descr,'/domain/cpu'))
                  cpu_model.attributes['fallback'] = 'allow'
                  cpu_model.text = 'qemu64'
                end
                vmx_feature = REXML::XPath.first(xml_descr,'/domain/cpu/feature[@name="vmx"]')
                svm_feature = REXML::XPath.first(xml_descr,'/domain/cpu/feature[@name="svm"]')
                if config.nested
                  if vmx_feature.nil?
                    descr_changed = true
                    vmx_feature = REXML::Element.new('feature', REXML::XPath.first(xml_descr,'/domain/cpu'))
                    vmx_feature.attributes['policy'] = 'optional'
                    vmx_feature.attributes['name'] = 'vmx'
                  end
                  if svm_feature.nil?
                    descr_changed = true
                    svm_feature = REXML::Element.new('feature', REXML::XPath.first(xml_descr,'/domain/cpu'))
                    svm_feature.attributes['policy'] = 'optional'
                    svm_feature.attributes['name'] = 'svm'
                  end
                else
                  if !vmx_feature.nil?
                    descr_changed = true
                    cpu.delete_element(vmx_feature)
                  end
                  if !svm_feature.nil?
                    descr_changed = true
                    cpu.delete_element(svm_feature)
                  end
                end
              else
                if cpu.elements.to_a.length > 0
                  descr_changed = true
                  cpu.elements.each {|elem|
                    cpu.delete_element(elem)
                  }
                end
              end

              # Graphics
              graphics = REXML::XPath.first(xml_descr,'/domain/devices/graphics')
              if graphics.attributes['type'] != config.graphics_type
                descr_changed = true
                graphics.attributes['type'] = config.graphics_type
              end
              if graphics.attributes['listen'] != config.graphics_ip
                descr_changed = true
                graphics.attributes['listen'] = config.graphics_ip
                graphics.delete_element('//listen')
              end
              if graphics.attributes['autoport'] != config.graphics_autoport
                descr_changed = true
                graphics.attributes['autoport'] = config.graphics_autoport
                if config.graphics_autoport == 'no'
                  graphics.attributes['port'] = config.graphics_port
                end
              end
              if graphics.attributes['keymap'] != config.keymap
                descr_changed = true
                graphics.attributes['keymap'] = config.keymap
              end
              if graphics.attributes['passwd'] != config.graphics_passwd
                descr_changed = true
                if config.graphics_passwd.nil?
                  graphics.attributes.delete 'passwd'
                else
                  graphics.attributes['passwd'] = config.graphics_passwd
                end
              end

              # Video device
              video = REXML::XPath.first(xml_descr,'/domain/devices/video/model')
              if video.attributes['type'] != config.video_type || video.attributes['vram'] != config.video_vram
                descr_changed = true
                video.attributes.each_attribute {|attr| video.attributes.delete attr}
                video.attributes['type'] = config.video_type
                video.attributes['vram'] = config.video_vram
              end

              # Apply
              if descr_changed
                begin
                  libvirt_domain.undefine
                  new_descr = ""
                  xml_descr.write new_descr
                  server = env[:machine].provider.driver.connection.servers.create(xml: new_descr)
                rescue Fog::Errors::Error => e
                  server = env[:machine].provider.driver.connection.servers.create(xml: descr)
                  raise Errors::FogCreateServerError, error_message:  e.message
                end
              end
            rescue => e
              env[:ui].error("Error when updating domain settings: #{e.message}")
            end
            # Actually start the domain
            domain.start
          rescue => e
            raise Errors::FogError, :message => e.message
          end

          @app.call(env)
        end
      end

    end
  end
end