require 'socket'

class UNIXSocket
  UNICORN_PEERADDR = '127.0.0.1'.freeze
  def unicorn_peeraddr
    UNICORN_PEERADDR
  end
end

class TCPSocket
  def unicorn_peeraddr
    peeraddr.last
  end
end

module Unicorn
  module SocketHelper
    include Socket::Constants

    def set_server_sockopt(sock, opt)
      opt ||= {}
      if opt[:rcvbuf] || opt[:sndbuf]
        log_buffer_sizes(sock, "before: ")
        sock.setsockopt(SOL_SOCKET, SO_RCVBUF, opt[:rcvbuf]) if opt[:rcvbuf]
        sock.setsockopt(SOL_SOCKET, SO_SNDBUF, opt[:sndbuf]) if opt[:sndbuf]
        log_buffer_sizes(sock, " after: ")
      end
      sock.listen(opt[:backlog] || 1024)
    end

    def log_buffer_sizes(sock, pfx = '')
      respond_to?(:logger) or return
      rcvbuf = sock.getsockopt(SOL_SOCKET, SO_RCVBUF).unpack('i')
      sndbuf = sock.getsockopt(SOL_SOCKET, SO_SNDBUF).unpack('i')
      logger.info "#{pfx}#{sock_name(sock)} rcvbuf=#{rcvbuf} sndbuf=#{sndbuf}"
    end

    # creates a new server, socket. address may be a HOST:PORT or
    # an absolute path to a UNIX socket.  address can even be a Socket
    # object in which case it is immediately returned
    def bind_listen(address = '0.0.0.0:8080', opt = { :backlog => 1024 })
      return address unless String === address

      sock = if address[0..0] == "/"
        if File.exist?(address)
          if File.socket?(address)
            if self.respond_to?(:logger)
              logger.info "unlinking existing socket=#{address}"
            end
            File.unlink(address)
          else
            raise ArgumentError,
                  "socket=#{address} specified but it is not a socket!"
          end
        end
        old_umask = File.umask(0)
        begin
          UNIXServer.new(address)
        ensure
          File.umask(old_umask)
        end
      elsif address =~ /^(\d+\.\d+\.\d+\.\d+):(\d+)$/
        TCPServer.new($1, $2.to_i)
      else
        raise ArgumentError, "Don't know how to bind: #{address}"
      end
      set_server_sockopt(sock, opt)
      sock
    end

    # Returns the configuration name of a socket as a string.  sock may
    # be a string value, in which case it is returned as-is
    # Warning: TCP sockets may not always return the name given to it.
    def sock_name(sock)
      case sock
      when String then sock
      when UNIXServer
        Socket.unpack_sockaddr_un(sock.getsockname)
      when TCPServer
        Socket.unpack_sockaddr_in(sock.getsockname).reverse!.join(':')
      when Socket
        begin
          Socket.unpack_sockaddr_in(sock.getsockname).reverse!.join(':')
        rescue ArgumentError
          Socket.unpack_sockaddr_un(sock.getsockname)
        end
      else
        raise ArgumentError, "Unhandled class #{sock.class}: #{sock.inspect}"
      end
    end

    # casts a given Socket to be a TCPServer or UNIXServer
    def server_cast(sock)
      begin
        Socket.unpack_sockaddr_in(sock.getsockname)
        TCPServer.for_fd(sock.fileno)
      rescue ArgumentError
        UNIXServer.for_fd(sock.fileno)
      end
    end

  end # module SocketHelper
end # module Unicorn