class Excon::Socket

def connect
  @socket = nil
  exception = nil
  addrinfo = if @proxy
    ::Socket.getaddrinfo(@proxy[:host], @proxy[:port].to_i, nil, ::Socket::Constants::SOCK_STREAM)
  else
    ::Socket.getaddrinfo(@params[:host], @params[:port].to_i, nil, ::Socket::Constants::SOCK_STREAM)
  end
  addrinfo.each do |_, port, _, ip, a_family, s_type|
    # nonblocking connect
    begin
      sockaddr = ::Socket.sockaddr_in(port, ip)
      socket = ::Socket.new(a_family, s_type, 0)
      socket.connect_nonblock(sockaddr)
      @socket = socket
      break
    rescue Errno::EINPROGRESS
      IO.select(nil, [socket], nil, @params[:connect_timeout])
      begin
        socket.connect_nonblock(sockaddr)
        @socket = socket
        break
      rescue Errno::EISCONN
        @socket = socket
        break
      rescue SystemCallError => exception
        socket.close
        next
      end
    rescue SystemCallError => exception
      socket.close
      next
    end
  end
  unless @socket
    # this will be our last encountered exception
    raise exception
  end
end

def initialize(params = {}, proxy = nil)
  @params, @proxy = params, proxy
  @read_buffer, @write_buffer = '', ''
  @eof = false
  connect
end

def read(max_length=nil)
  return nil if @eof
  begin
    if max_length
      until @read_buffer.length >= max_length
        @read_buffer << @socket.read_nonblock(max_length - @read_buffer.length)
      end
    else
      while true
        @read_buffer << @socket.read_nonblock(CHUNK_SIZE)
      end
    end
  rescue OpenSSL::SSL::SSLError => error
    if error.message == 'read would block'
      if IO.select([@socket], nil, nil, @params[:read_timeout])
        retry
      else
        raise(Excon::Errors::Timeout.new("read timeout reached"))
      end
    end
  rescue Errno::EAGAIN, Errno::EWOULDBLOCK, IO::WaitReadable
    if IO.select([@socket], nil, nil, @params[:read_timeout])
      retry
    else
      raise(Excon::Errors::Timeout.new("read timeout reached"))
    end
  rescue EOFError
    @eof = true
  end
  if max_length
    @read_buffer.slice!(0, max_length)
  else
    # read until EOFError, so return everything
    @read_buffer.slice!(0, @read_buffer.length)
  end
end

def write(data)
  @write_buffer << data
  until @write_buffer.empty?
    begin
      max_length = [@write_buffer.length, Excon::CHUNK_SIZE].min
      written = @socket.write_nonblock(@write_buffer.slice(0, max_length))
      @write_buffer.slice!(0, written)
    rescue OpenSSL::SSL::SSLError => error
      if error.message == 'write would block'
        if IO.select(nil, [@socket], nil, @params[:write_timeout])
          retry
        else
          raise(Excon::Errors::Timeout.new("write timeout reached"))
        end
      end
    rescue Errno::EAGAIN, Errno::EWOULDBLOCK, IO::WaitWritable
      if IO.select(nil, [@socket], nil, @params[:write_timeout])
        retry
      else
        raise(Excon::Errors::Timeout.new("write timeout reached"))
      end
    end
  end
end