# frozen_string_literal: false
require_relative 'base'
require_relative '../config'

module Processing
  class WatchException < StandardError
  end

  # A sketch loader, observer, and reloader, to tighten
  # the feedback between code and effect.
  class Watcher
    # Sic a new Processing::Watcher on the sketch
    WATCH_MESSAGE ||= <<-EOS.freeze
    Warning:
    To protect you from running watch mode in a top level
    directory with lots of nested ruby or GLSL files we
    limit the number of files to watch to %d.
    If you really want to watch %d files you should
    increase MAX_WATCH in ~/.jruby_art/config.yml

    EOS
    SLEEP_TIME = 0.2
    def initialize
      reload_files_to_watch
      @time = Time.now
      start_watching
    end

    # Kicks off a thread to watch the sketch, reloading JRubyArt
    # and restarting the sketch whenever it changes.
    def start_watching
      start_original
      Kernel.loop do
        if @files.find { |file| FileTest.exist?(file) && File.stat(file).mtime > @time }
          puts 'reloading sketch...'
          Processing.app && Processing.app.close
          java.lang.System.gc
          @time = Time.now
          start_runner
          reload_files_to_watch
        end
        sleep SLEEP_TIME
      end
    end

    # Convenience function to report errors when loading and running a sketch,
    # instead of having them eaten by the thread they are loaded in.
    def report_errors
      yield
    rescue Exception => e
      wformat = 'Exception occured while running sketch %s...'
      tformat = "Backtrace:\n\t%s"
      warn format(wformat, File.basename(SKETCH_PATH))
      puts format(tformat, e.backtrace.join("\n\t"))
    end

    def start_original
      @runner = Thread.start do
        report_errors do
          Processing.load_and_run_sketch
        end
      end
    end

    def start_runner
      @runner.kill if @runner && @runner.alive?
      @runner.join
      @runner = nil
      start_original
    end

    def reload_files_to_watch
      @files = Dir.glob(File.join(SKETCH_ROOT, '**/*.{rb,glsl}'))
      count = @files.length
      max_watch = RP_CONFIG.fetch('MAX_WATCH', 32)
      return unless count > max_watch.to_i
      warn format(WATCH_MESSAGE, max_watch, count)
      abort
    end
  end
end

Processing::Watcher.new