class Solargraph::LanguageServer::Transport::DataReader

def initialize
  @in_header = true
  @content_length = 0
  @buffer = ''
end

def parse_message_from_buffer
  begin
    msg = JSON.parse(@buffer)
    @message_handler.call msg unless @message_handler.nil?
  rescue JSON::ParserError => e
    STDERR.puts "Failed to parse request: #{e.message}"
    STDERR.puts "Buffer: #{@buffer}"
  ensure
    @buffer.clear
    @in_header = true
    @content_length = 0
  end
end

def prepare_to_parse_message
  @in_header = false
  @buffer.each_line do |line|
    parts = line.split(':').map(&:strip)
    if parts[0] == 'Content-Length'
      @content_length = parts[1].to_i
      break
    end
  end
  @buffer.clear
end

def receive data
  data.each_char do |char|
    @buffer.concat char
    if @in_header
      prepare_to_parse_message if @buffer.end_with?("\r\n\r\n")
    else
      parse_message_from_buffer if @buffer.bytesize == @content_length
    end
  end
end

def set_message_handler &block
  @message_handler = block
end