class Listen::Adapter::Base

def _log_exception(msg, caller_stack)
  formatted = format(
    msg,
    $ERROR_INFO,
    $ERROR_POSITION * "\n",
    caller_stack * "\n"
  )
  Listen.logger.error(formatted)
end

def _queue_change(type, dir, rel_path, options)
  @snapshots[dir].invalidate(type, rel_path, options)
end

def _stop
  @run_thread&.kill
  @run_thread = nil
end

def _timed(title)
  start = MonotonicTime.now
  yield
  diff = MonotonicTime.now - start
  Listen.logger.info format('%s: %.05f seconds', title, diff)
rescue
  Listen.logger.warn "#{title} crashed: #{$ERROR_INFO.inspect}"
  raise
end

def configure
  if @configured
    Listen.logger.warn('Adapter already configured!')
    return
  end
  @configured = true
  @callbacks ||= {}
  config.directories.each do |dir|
    callback = @callbacks[dir] || lambda do |event|
      _process_event(dir, event)
    end
    @callbacks[dir] = callback
    _configure(dir, &callback)
  end
  @snapshots ||= {}
  # TODO: separate config per directory (some day maybe)
  change_config = Change::Config.new(config.queue, config.silencer)
  config.directories.each do |dir|
    record = Record.new(dir, config.silencer)
    snapshot = Change.new(change_config, record)
    @snapshots[dir] = snapshot
  end
end

def initialize(config)
  @started = false
  @config = config
  @configured = nil
  fail 'No directories to watch!' if config.directories.empty?
  defaults = self.class.const_get('DEFAULTS')
  @options = Listen::Options.new(config.adapter_options, defaults)
rescue
  _log_exception 'adapter config failed: %s:%s called from: %s', caller
  raise
end

def start
  configure
  if started?
    Listen.logger.warn('Adapter already started!')
    return
  end
  @started = true
  @run_thread = Listen::Thread.new("run_thread") do
    @snapshots.each_value do |snapshot|
      _timed('Record.build()') { snapshot.record.build }
    end
    _run
  end
end

def started?
  @started
end

def stop
  _stop
  config.queue.close # this causes queue.pop to return `nil` to the front-end
end

def usable?
  const_get('OS_REGEXP') =~ RbConfig::CONFIG['target_os']
end