module ElasticAPM

def self.add_filter(key, callback = nil, &block)
  if callback.nil? && !block_given?
    raise ArgumentError, '#add_filter needs either `callback\' or a block'
  end
  agent && agent.add_filter(key, block || callback)
end

def self.agent
  Agent.instance
end

def self.build_context(rack_env)
  agent && agent.build_context(rack_env)
end

def self.current_transaction
  agent && agent.current_transaction
end

def self.report(exception, handled: true)
  agent && agent.report(exception, handled: handled)
end

def self.report_message(message, **attrs)
  agent && agent.report_message(message, backtrace: caller, **attrs)
end

def self.running?
  Agent.running?
end

def self.set_custom_context(custom)
  agent && agent.set_custom_context(custom)
end

def self.set_tag(key, value)
  agent && agent.set_tag(key, value)
end

def self.set_user(user)
  agent && agent.set_user(user)
end

def self.span(name, type = nil, context: nil, include_stacktrace: true,
  &block)
  return (block_given? ? yield : nil) unless agent
  agent.span(
    name,
    type,
    context: context,
    backtrace: include_stacktrace ? caller : nil,
    &block
  )
end

def self.start(config = {})
  Agent.start config
end

def self.stop
  Agent.stop
end

def self.transaction(name, type = nil, context: nil, &block)
  return (block_given? ? yield : nil) unless agent
  agent.transaction(name, type, context: context, &block)
end