module SemanticLogger::Appender

def self.build(io: nil, file_name: nil, appender: nil, metric: nil, logger: nil, **args, &block)
  if file_name
    SemanticLogger::Appender::File.new(file_name, **args, &block)
  elsif io
    SemanticLogger::Appender::IO.new(io, **args, &block)
  elsif logger
    SemanticLogger::Appender::Wrapper.new(logger: logger, **args, &block)
  elsif appender
    if appender.is_a?(Symbol)
      SemanticLogger::Utils.constantize_symbol(appender).new(**args)
    elsif appender.is_a?(Subscriber)
      appender
    else
      raise(ArgumentError,
            "Parameter :appender must be either a Symbol or an object derived from SemanticLogger::Subscriber, not: #{appender.inspect}")
    end
  elsif metric
    if metric.is_a?(Symbol)
      SemanticLogger::Utils.constantize_symbol(metric, "SemanticLogger::Metric").new(**args)
    elsif metric.is_a?(Subscriber)
      metric
    else
      raise(ArgumentError,
            "Parameter :metric must be either a Symbol or an object derived from SemanticLogger::Subscriber, not: #{appender.inspect}")
    end
  else
    raise(ArgumentError,
          "To create an appender it must supply one of the following: :io, :file_name, :appender, :metric, or :logger")
  end
end

def self.factory(async: false, batch: nil,
                 max_queue_size: 10_000, lag_check_interval: 1_000, lag_threshold_s: 30,
                 batch_size: 300, batch_seconds: 5,
                 **args,
                 &block)
  appender = build(**args, &block)
  # If appender implements #batch, then it should use the batch proxy by default.
  batch    = true if batch.nil? && appender.respond_to?(:batch)
  if batch == true
    Appender::AsyncBatch.new(
      appender:        appender,
      max_queue_size:  max_queue_size,
      lag_threshold_s: lag_threshold_s,
      batch_size:      batch_size,
      batch_seconds:   batch_seconds
    )
  elsif async == true
    Appender::Async.new(
      appender:           appender,
      max_queue_size:     max_queue_size,
      lag_check_interval: lag_check_interval,
      lag_threshold_s:    lag_threshold_s
    )
  else
    appender
  end
end