module Orchestration::TFTP
  def self.included(base)
    base.send :include, InstanceMethods
    base.class_eval do
      after_validation :validate_tftp, :queue_tftp
      before_destroy :queue_tftp_destroy

      # required for pxe template url helpers
      include Rails.application.routes.url_helpers
    end
  end

  module InstanceMethods

    def tftp?
      !!(subnet and subnet.tftp?) and managed? and capabilities.include?(:build)
    end

    def tftp
      subnet.tftp_proxy(:variant => operatingsystem.pxe_variant) if tftp?
    end

    protected

    # Adds the host to the forward and reverse TFTP zones
    # +returns+ : Boolean true on success
    def setTFTP
      logger.info "Add the TFTP configuration for #{name}"
      tftp.set mac, :pxeconfig => generate_pxe_template
    rescue => e
      failure _("Failed to set TFTP: %s") % proxy_error(e)
    end

    # Removes the host from the forward and reverse TFTP zones
    # +returns+ : Boolean true on success
    def delTFTP
      logger.info "Delete the TFTP configuration for #{name}"
      tftp.delete mac
    rescue => e
      failure _("Failed to delete TFTP: %s") % proxy_error(e)
    end

    def setTFTPBootFiles
      logger.info "Fetching required TFTP boot files for #{name}"
      valid = true
      operatingsystem.pxe_files(medium, architecture).each do |bootfile_info|
        for prefix, path in bootfile_info do
          valid = false unless tftp.fetch_boot_file(:prefix => prefix.to_s, :path => path)
        end
      end
      failure _("Failed to fetch boot files") unless valid
      valid
    rescue => e
      failure _("Failed to fetch boot files: %s") % proxy_error(e)
    end

    #empty method for rollbacks
    def delTFTPBootFiles
    end

    private

    def validate_tftp
      return unless tftp?
      return unless operatingsystem
      return if Rails.env == "test"
      if configTemplate({:kind => operatingsystem.template_kind}).nil? and configTemplate({:kind => "gPXE"}).nil?
        failure _("No %{template_kind} templates were found for this host, make sure you define at least one in your %{os} settings") % { :template_kind => operatingsystem.template_kind, :os => os }
      end
    end

    def generate_pxe_template
      # this is the only place we generate a template not via a web request
      # therefore some workaround is required to "render" the template.

      prefix   = operatingsystem.pxe_prefix(arch)
      @kernel = os.kernel(arch)
      @initrd = os.initrd(arch)
      # work around for ensuring that people can use @host as well, as tftp templates were usually confusing.
      @host = self
      if build?
        pxe_render configTemplate({:kind => os.template_kind}).template
      else
        pxe_render ConfigTemplate.find_by_name("PXE Localboot Default").template
      end
    rescue => e
      failure _("Failed to generate %{template_kind} template: %{e}") % { :template_kind => os.template_kind, :e => e }
    end

    def queue_tftp
      return unless tftp? and errors.empty?
      # Jumpstart builds require only minimal tftp services. They do require a tftp object to query for the boot_server.
      return true if jumpstart?
      new_record? ? queue_tftp_create : queue_tftp_update
    end

    def queue_tftp_create
      queue.create(:name => _("TFTP Settings for %s") % self, :priority => 20,
                   :action => [self, :setTFTP])
      return unless build
      queue.create(:name => _("Fetch TFTP boot files for %s") % self, :priority => 25,
                   :action => [self, :setTFTPBootFiles])
    end

    def queue_tftp_update
      set_tftp = false
      # we switched build mode
      set_tftp = true unless old.build? != build?
      # medium or arch changed
      set_tftp = true if old.medium != medium or old.arch != arch
      # operating system changed
      set_tftp = true if os and old.os and (old.os.name != os.name or old.os != os)
      # MAC address changed
      if mac != old.mac
        set_tftp = true
        # clean up old TFTP reservation file
        if old.tftp?
          queue.create(:name => _("Remove old TFTP Settings for %s") % old, :priority => 19,
                       :action => [old, :delTFTP])
        end
      end
      queue_tftp_create  if set_tftp
    end

    def queue_tftp_destroy
      return unless tftp? and errors.empty?
      return true if jumpstart?
      queue.create(:name => _("TFTP Settings for %s") % self, :priority => 20,
                   :action => [self, :delTFTP])
    end

  end
end