require "set"

require "log4r"

require "vagrant/util/network_ip"
require "vagrant/util/scoped_hash_override"

module VagrantPlugins
  module ProviderVirtualBox
    module Action
      # This middleware class sets up all networking for the VirtualBox
      # instance. This includes host only networks, bridged networking,
      # forwarded ports, etc.
      #
      # This handles all the `config.vm.network` configurations.
      class Network
        include Vagrant::Util::NetworkIP
        include Vagrant::Util::ScopedHashOverride

        def initialize(app, env)
          @logger = Log4r::Logger.new("vagrant::plugins::virtualbox::network")
          @app    = app
        end

        def call(env)
          # TODO: Validate network configuration prior to anything below
          @env = env

          # Get the list of network adapters from the configuration
          network_adapters_config = env[:machine].provider_config.network_adapters.dup

          # Assign the adapter slot for each high-level network
          available_slots = Set.new(1..8)
          network_adapters_config.each do |slot, _data|
            available_slots.delete(slot)
          end

          @logger.debug("Available slots for high-level adapters: #{available_slots.inspect}")
          @logger.info("Determining network adapters required for high-level configuration...")
          available_slots = available_slots.to_a.sort
          env[:machine].config.vm.networks.each do |type, options|
            # We only handle private and public networks
            next if type != :private_network && type != :public_network

            options = scoped_hash_override(options, :virtualbox)

            # Figure out the slot that this adapter will go into
            slot = options[:adapter]
            if !slot
              if available_slots.empty?
                raise Vagrant::Errors::VirtualBoxNoRoomForHighLevelNetwork
              end

              slot = available_slots.shift
            end

            # Configure it
            data = nil
            if type == :private_network
              # private_network = hostonly
              data        = [:hostonly, options]
            elsif type == :public_network
              # public_network = bridged
              data        = [:bridged, options]
            end

            # Store it!
            @logger.info(" -- Slot #{slot}: #{data[0]}")
            network_adapters_config[slot] = data
          end

          @logger.info("Determining adapters and compiling network configuration...")
          adapters = []
          networks = []
          network_adapters_config.each do |slot, data|
            type    = data[0]
            options = data[1]

            @logger.info("Network slot #{slot}. Type: #{type}.")

            # Get the normalized configuration for this type
            config = send("#{type}_config", options)
            config[:adapter] = slot
            @logger.debug("Normalized configuration: #{config.inspect}")

            # Get the VirtualBox adapter configuration
            adapter = send("#{type}_adapter", config)
            adapters << adapter
            @logger.debug("Adapter configuration: #{adapter.inspect}")

            # Get the network configuration
            network = send("#{type}_network_config", config)
            network[:auto_config] = config[:auto_config]
            networks << network
          end

          if !adapters.empty?
            # Enable the adapters
            @logger.info("Enabling adapters...")
            env[:ui].info I18n.t("vagrant.actions.vm.network.preparing")
            env[:machine].provider.driver.enable_adapters(adapters)
          end

          # Continue the middleware chain.
          @app.call(env)

          # If we have networks to configure, then we configure it now, since
          # that requires the machine to be up and running.
          if !adapters.empty? && !networks.empty?
            assign_interface_numbers(networks, adapters)

            # Only configure the networks the user requested us to configure
            networks_to_configure = networks.select { |n| n[:auto_config] }
            env[:ui].info I18n.t("vagrant.actions.vm.network.configuring")
            env[:machine].guest.configure_networks(networks_to_configure)
          end
        end

        def bridged_config(options)
          return {
            :auto_config                     => true,
            :bridge                          => nil,
            :mac                             => nil,
            :nic_type                        => nil,
            :use_dhcp_assigned_default_route => false
          }.merge(options || {})
        end

        def bridged_adapter(config)
          # Find the bridged interfaces that are available
          bridgedifs = @env[:machine].provider.driver.read_bridged_interfaces
          bridgedifs.delete_if { |interface| interface[:status] == "Down" }

          # The name of the chosen bridge interface will be assigned to this
          # variable.
          chosen_bridge = nil

          if config[:bridge]
            @logger.debug("Bridge was directly specified in config, searching for: #{config[:bridge]}")

            # Search for a matching bridged interface
            bridgedifs.each do |interface|
              if interface[:name].downcase == config[:bridge].downcase
                @logger.debug("Specific bridge found as configured in the Vagrantfile. Using it.")
                chosen_bridge = interface[:name]
                break
              end
            end

            # If one wasn't found, then we notify the user here.
            if !chosen_bridge
              @env[:ui].info I18n.t("vagrant.actions.vm.bridged_networking.specific_not_found",
                                    :bridge => config[:bridge])
            end
          end

          # If we still don't have a bridge chosen (this means that one wasn't
          # specified in the Vagrantfile, or the bridge specified in the Vagrantfile
          # wasn't found), then we fall back to the normal means of searchign for a
          # bridged network.
          if !chosen_bridge
            if bridgedifs.length == 1
              # One bridgable interface? Just use it.
              chosen_bridge = bridgedifs[0][:name]
              @logger.debug("Only one bridged interface available. Using it by default.")
            else
              # More than one bridgable interface requires a user decision, so
              # show options to choose from.
              @env[:ui].info I18n.t("vagrant.actions.vm.bridged_networking.available",
                                    :prefix => false)
              bridgedifs.each_index do |index|
                interface = bridgedifs[index]
                @env[:ui].info("#{index + 1}) #{interface[:name]}", :prefix => false)
              end

              # The range of valid choices
              valid = Range.new(1, bridgedifs.length)

              # The choice that the user has chosen as the bridging interface
              choice = nil
              while !valid.include?(choice)
                choice = @env[:ui].ask("What interface should the network bridge to? ")
                choice = choice.to_i
              end

              chosen_bridge = bridgedifs[choice - 1][:name]
            end
          end

          @logger.info("Bridging adapter #{config[:adapter]} to #{chosen_bridge}")

          # Given the choice we can now define the adapter we're using
          return {
            :adapter     => config[:adapter],
            :type        => :bridged,
            :bridge      => chosen_bridge,
            :mac_address => config[:mac],
            :nic_type    => config[:nic_type]
          }
        end

        def bridged_network_config(config)
          return {
            :type => :dhcp,
            :use_dhcp_assigned_default_route => config[:use_dhcp_assigned_default_route]
          }
        end

        def hostonly_config(options)
          options = {
            :auto_config => true,
            :netmask     => "255.255.255.0",
            :type        => :static
          }.merge(options)

          # Default IP is in the 20-bit private network block for DHCP based networks
          options[:ip] = "172.28.128.1" if options[:type] == :dhcp

          # Calculate our network address for the given IP/netmask
          netaddr  = network_address(options[:ip], options[:netmask])

          # Verify that a host-only network subnet would not collide
          # with a bridged networking interface.
          #
          # If the subnets overlap in any way then the host only network
          # will not work because the routing tables will force the
          # traffic onto the real interface rather than the VirtualBox
          # interface.
          @env[:machine].provider.driver.read_bridged_interfaces.each do |interface|
            that_netaddr = network_address(interface[:ip], interface[:netmask])
            raise Vagrant::Errors::NetworkCollision if \
              netaddr == that_netaddr && interface[:status] != "Down"
          end

          # Split the IP address into its components
          ip_parts = netaddr.split(".").map { |i| i.to_i }

          # Calculate the adapter IP, which we assume is the IP ".1" at
          # the end usually.
          adapter_ip    = ip_parts.dup
          adapter_ip[3] += 1
          options[:adapter_ip] ||= adapter_ip.join(".")

          dhcp_options = {}
          if options[:type] == :dhcp
            # Calculate the DHCP server IP, which is the network address
            # with the final octet + 2. So "172.28.0.0" turns into "172.28.0.2"
            dhcp_ip    = ip_parts.dup
            dhcp_ip[3] += 2
            dhcp_options[:dhcp_ip] ||= dhcp_ip.join(".")

            # Calculate the lower and upper bound for the DHCP server
            dhcp_lower    = ip_parts.dup
            dhcp_lower[3] += 3
            dhcp_options[:dhcp_lower] ||= dhcp_lower.join(".")

            dhcp_upper    = ip_parts.dup
            dhcp_upper[3] = 254
            dhcp_options[:dhcp_upper] ||= dhcp_upper.join(".")
          end

          return {
            :adapter_ip  => options[:adapter_ip],
            :auto_config => options[:auto_config],
            :ip          => options[:ip],
            :mac         => nil,
            :netmask     => options[:netmask],
            :nic_type    => nil,
            :type        => options[:type]
          }.merge(dhcp_options)
        end

        def hostonly_adapter(config)
          @logger.info("Searching for matching hostonly network: #{config[:ip]}")
          interface = hostonly_find_matching_network(config)

          if !interface
            @logger.info("Network not found. Creating if we can.")

            # It is an error if a specific host only network name was specified
            # but the network wasn't found.
            if config[:name]
              raise Vagrant::Errors::NetworkNotFound, :name => config[:name]
            end

            # Create a new network
            interface = hostonly_create_network(config)
            @logger.info("Created network: #{interface[:name]}")
          end

          if config[:type] == :dhcp
            # Check that if there is a DHCP server attached on our interface,
            # then it is identical. Otherwise, we can't set it.
            if interface[:dhcp]
              valid = interface[:dhcp][:ip] == config[:dhcp_ip] &&
                  interface[:dhcp][:lower] == config[:dhcp_lower] &&
                  interface[:dhcp][:upper] == config[:dhcp_upper]

              raise Errors::NetworkDHCPAlreadyAttached if !valid

              @logger.debug("DHCP server already properly configured")
            else
              # Configure the DHCP server for the network.
              @logger.debug("Creating a DHCP server...")
              @env[:machine].provider.driver.create_dhcp_server(interface[:name], config)
            end
          end

          return {
            :adapter  => config[:adapter],
            :hostonly => interface[:name],
            :mac      => config[:mac],
            :nic_type => config[:nic_type],
            :type     => :hostonly
          }
        end

        def hostonly_network_config(config)
          return {
            :type       => config[:type],
            :adapter_ip => config[:adapter_ip],
            :ip         => config[:ip],
            :netmask    => config[:netmask]
          }
        end

        def nat_config(options)
          return {
            :auto_config => false
          }
        end

        def nat_adapter(config)
          return {
            :adapter => config[:adapter],
            :type    => :nat,
          }
        end

        def nat_network_config(config)
          return {}
        end

        #-----------------------------------------------------------------
        # Misc. helpers
        #-----------------------------------------------------------------
        # Assigns the actual interface number of a network based on the
        # enabled NICs on the virtual machine.
        #
        # This interface number is used by the guest to configure the
        # NIC on the guest VM.
        #
        # The networks are modified in place by adding an ":interface"
        # field to each.
        def assign_interface_numbers(networks, adapters)
          current = 0
          adapter_to_interface = {}

          # Make a first pass to assign interface numbers by adapter location
          vm_adapters = @env[:machine].provider.driver.read_network_interfaces
          vm_adapters.sort.each do |number, adapter|
            if adapter[:type] != :none
              # Not used, so assign the interface number and increment
              adapter_to_interface[number] = current
              current += 1
            end
          end

          # Make a pass through the adapters to assign the :interface
          # key to each network configuration.
          adapters.each_index do |i|
            adapter = adapters[i]
            network = networks[i]

            # Figure out the interface number by simple lookup
            network[:interface] = adapter_to_interface[adapter[:adapter]]
          end
        end

        #-----------------------------------------------------------------
        # Hostonly Helper Functions
        #-----------------------------------------------------------------
        # This creates a host only network for the given configuration.
        def hostonly_create_network(config)
          @env[:machine].provider.driver.create_host_only_network(
            :adapter_ip => config[:adapter_ip],
            :netmask    => config[:netmask]
          )
        end

        # This finds a matching host only network for the given configuration.
        def hostonly_find_matching_network(config)
          this_netaddr = network_address(config[:ip], config[:netmask])

          @env[:machine].provider.driver.read_host_only_interfaces.each do |interface|
            return interface if config[:name] && config[:name] == interface[:name]
            return interface if this_netaddr == \
              network_address(interface[:ip], interface[:netmask])
          end

          nil
        end
      end
    end
  end
end