class Middleman::CoreExtensions::FileWatcher::API

def changed(matcher=nil, &block)
  @_changed << [block, matcher] if block_given?
  @_changed
end

def deleted(matcher=nil, &block)
  @_deleted << [block, matcher] if block_given?
  @_deleted
end

def did_change(path)
  path = Pathname(path)
  return if ignored?(path)
  logger.debug "== File Change: #{path}"
  @known_paths << path
  self.run_callbacks(path, :changed)
end

def did_delete(path)
  path = Pathname(path)
  return if ignored?(path)
  logger.debug "== File Deletion: #{path}"
  @known_paths.delete(path)
  self.run_callbacks(path, :deleted)
end

def exists?(path)
  p = Pathname(path)
  p = p.relative_path_from(Pathname(@app.root)) if !p.relative?
  @known_paths.include?(p)
end

def find_new_files(path)
  reload_path(path, true)
end

def ignored?(path)
  path = path.to_s
  app.config[:file_watcher_ignore].any? { |r| path =~ r }
end

def initialize(app)
  @app = app
  @known_paths = Set.new
  @_changed = []
  @_deleted = []
end

def reload_path(path, only_new=false)
  # chdir into the root directory so Pathname can work with relative paths
  Dir.chdir @app.root_path do
    path = Pathname(path)
    return unless path.exist?
    glob = (path + "**").to_s
    subset = @known_paths.select { |p| p.fnmatch(glob) }
    ::Middleman::Util.all_files_under(path).each do |filepath|
      next if only_new && subset.include?(filepath)
      subset.delete(filepath)
      did_change(filepath)
    end
    subset.each(&method(:did_delete)) unless only_new
  end
end

def run_callbacks(path, callbacks_name)
  path = path.to_s
  self.send(callbacks_name).each do |callback, matcher|
    next unless matcher.nil? || path.match(matcher)
    @app.instance_exec(path, &callback)
  end
end