
module Daemons
  class ApplicationGroup
    attr_reader :app_name
    attr_reader :script

    attr_reader :monitor

    attr_reader :options

    attr_reader :applications

    attr_accessor :controller_argv
    attr_accessor :app_argv

    attr_accessor :dir_mode
    attr_accessor :dir

    # true if the application is supposed to run in multiple instances
    attr_reader :multiple

    def initialize(app_name, options = {})
      @app_name = app_name
      @options = options

      if options[:script]
        @script = File.expand_path(options[:script])
      end

      @monitor = nil

      @multiple = options[:multiple] || false

      @dir_mode = options[:dir_mode] || :script
      @dir = options[:dir] || ''

      @keep_pid_files = options[:keep_pid_files] || false
      @no_pidfiles = options[:no_pidfiles] || false

      @applications = []
    end

    # Setup the application group.
    # Currently this functions calls <tt>find_applications</tt> which finds
    # all running instances of the application and populates the application array.
    #
    def setup
      @applications = find_applications(pidfile_dir)
    end

    def pidfile_dir
      PidFile.dir(@dir_mode, @dir, script)
    end

    def find_applications(dir)
      if @no_pidfiles
        return find_applications_by_app_name(app_name)
      else
        return find_applications_by_pidfiles(dir)
      end
    end

    # TODO: identifiy the monitor process
    def find_applications_by_app_name(app_name)
      pids = []

      begin
        x = `ps auxw | grep -v grep | awk '{print $2, $11, $12}' | grep #{app_name}`
        if x && x.chomp!
          processes = x.split(/\n/).compact
          processes = processes.delete_if do |p|
            pid, name, add = p.split(/\s/)
            # We want to make sure that the first part of the process name matches
            # so that app_name matches app_name_22

            app_name != name[0..(app_name.length - 1)] and not add.include?(app_name)
          end
          pids = processes.map { |p| p.split(/\s/)[0].to_i }
        end
        rescue ::Exception
      end

      pids.map do |f|
        app = Application.new(self, {}, PidMem.existing(f))
        setup_app(app)
        app
      end
    end

    def find_applications_by_pidfiles(dir)
      @monitor = Monitor.find(dir, app_name + '_monitor')

      pid_files = PidFile.find_files(dir, app_name, ! @keep_pid_files)
      pid_files.map do |f|
        app = Application.new(self, {}, PidFile.existing(f))
        setup_app(app)
        app
      end
    end

    def new_application(add_options = {})
      if @applications.size > 0 && !@multiple
        if options[:force]
          @applications.delete_if do |a|
            unless a.running?
              a.zap
              true
            end
          end
        end

        fail RuntimeException.new('there is already one or more instance(s) of the program running') unless @applications.empty?
      end

      app = Application.new(self, add_options)

      setup_app(app)

      @applications << app

      app
    end

    def setup_app(app)
      app.controller_argv = @controller_argv
      app.app_argv = @app_argv
      if @options[:show_status_callback]
        app.show_status_callback = @options[:show_status_callback]
      end
    end
    private :setup_app

    def create_monitor(an_app)
      if @monitor && options[:monitor]
        @monitor.stop
        @monitor = nil
      end

      if options[:monitor]
        @monitor = Monitor.new(an_app)
        @monitor.start(self)
      end
    end

    def start_all
      @monitor.stop if @monitor
      @monitor = nil

      pids = []
      @applications.each do |a|
        pids << fork do
          a.start
        end
      end
      pids.each { |pid| Process.waitpid(pid) }
    end

    def stop_all(no_wait = false)
      if @monitor
        @monitor.stop
        @monitor = nil
        setup
      end

      threads = []

      @applications.each do |a|
        threads << Thread.new do
          a.stop(no_wait)
        end
      end

      threads.each { |t| t.join }
    end

    def reload_all
      @applications.each { |a| a.reload }
    end

    def zap_all
      @monitor.stop if @monitor

      @applications.each { |a| a.zap }
    end

    def show_status
      @applications.each { |a| a.show_status }
    end
    
    # Check whether at least one of the applications in the group is running. If yes, return true.
    def running?
      @applications.each { |a| return true if a.running? }
      return false
    end
    
  end
end
