class Mongo::Error::Parser

def append(message, error)
  if message.length > 1
    message.concat(", #{error}")
  else
    message.concat(error)
  end
end

def initialize(document, replies = nil, options = nil)
  @document = document || {}
  @replies = replies
  @options = if options
    options.dup
  else
    {}
  end.freeze
  parse!
end

def parse!
  @message = ""
  parse_single(@message, ERR)
  parse_single(@message, ERROR)
  parse_single(@message, ERRMSG)
  parse_multiple(@message, 'writeErrors')
  if write_concern_error_document
    parse_single(@message, ERRMSG, write_concern_error_document)
  end
  parse_flag(@message)
  parse_code
  parse_labels
  parse_wtimeout
end

def parse_code
  if document['ok'] == 1 || @options[:legacy]
    @code = @code_name = nil
  else
    @code = document['code']
    @code_name = document['codeName']
  end
  # Since there is only room for one code, do not replace
  # codes of the top level response with write concern error codes.
  # In practice this should never be an issue as a write concern
  # can only fail after the operation succeeds on the primary.
  if @code.nil? && @code_name.nil?
    if subdoc = write_concern_error_document
      @code = subdoc['code']
      @code_name = subdoc['codeName']
    end
  end
  if @code.nil? && @code_name.nil?
    # If we have writeErrors, and all of their codes are the same,
    # use that code. Otherwise don't set the code
    if write_errors = document['writeErrors']
      codes = write_errors.map { |e| e['code'] }.compact
      if codes.uniq.length == 1
        @code = codes.first
        # code name may not be returned by the server
        @code_name = write_errors.map { |e| e['codeName'] }.compact.first
      end
    end
  end
end

def parse_flag(message)
  if replies && replies.first &&
      (replies.first.respond_to?(:cursor_not_found?)) && replies.first.cursor_not_found?
    append(message, CURSOR_NOT_FOUND)
  end
end

def parse_labels
  @labels = document['errorLabels'] || []
end

def parse_multiple(message, key)
  if errors = document[key]
    errors.each do |error|
      parse_single(message, ERRMSG, error)
    end
  end
end

def parse_single(message, key, doc = document)
  if error = doc[key]
    append(message ,"#{error} (#{doc[CODE]})")
  end
end

def parse_wtimeout
  @wtimeout = write_concern_error_document &&
    write_concern_error_document['errInfo'] &&
    write_concern_error_document['errInfo']['wtimeout']
end

def write_concern_error?
  !!write_concern_error_document
end

def write_concern_error_code
  write_concern_error_document && write_concern_error_document['code']
end

def write_concern_error_code_name
  write_concern_error_document && write_concern_error_document['codeName']
end

def write_concern_error_document
  document['writeConcernError']
end