module God
  module CLI
    class Command
      def initialize(command, options, args)
        @command = command
        @options = options
        @args = args

        dispatch
      end

      def setup
        # connect to drb unix socket
        @server = DRbObject.new(nil, God::Socket.socket(@options[:port]))

        # ping server to ensure that it is responsive
        begin
          @server.ping
        rescue DRb::DRbConnError
          puts 'The server is not available (or you do not have permissions to access it)'
          abort
        end
      end

      def dispatch
        if %w[load status signal log quit terminate].include?(@command)
          setup
          send("#{@command}_command")
        elsif %w[start stop restart monitor unmonitor remove].include?(@command)
          setup
          lifecycle_command
        elsif @command == 'check'
          check_command
        else
          puts "Command '#{@command}' is not valid. Run 'god --help' for usage"
          abort
        end
      end

      def load_command
        file = @args[1]
        action = @args[2] || 'leave'

        unless ['stop', 'remove', 'leave', ''].include?(action)
          puts "Command '#{@command}' action must be either 'stop', 'remove' or 'leave'"
          exit(1)
        end

        puts "Sending '#{@command}' command with action '#{action}'"
        puts

        abort "File not found: #{file}" unless File.exist?(file)

        affected, errors, removed = *@server.running_load(File.read(file), File.expand_path(file), action)

        # output response
        unless affected.empty?
          puts 'The following tasks were affected:'
          affected.each do |w|
            puts "  #{w}"
          end
        end

        unless removed.empty?
          puts 'The following tasks were removed:'
          removed.each do |w|
            puts "  #{w}"
          end
        end

        return if errors.empty?

        puts errors
        exit(1)
      end

      def status_command
        exitcode = 0
        statuses = @server.status
        groups = {}
        statuses.each do |name, status|
          g = status[:group] || ''
          groups[g] ||= {}
          groups[g][name] = status
        end

        if (item = @args[1])
          if (single = statuses[item])
            # specified task (0 -> up, 1 -> unmonitored, 2 -> other)
            state = single[:state]
            puts "#{item}: #{state}"
            exitcode = case state
                       when :up
                         0
                       when :unmonitored
                         1
                       else
                         2
                       end
          elsif groups[item]
            # specified group (0 -> up, N -> other)
            puts "#{item}:"
            groups[item].keys.sort.each do |name|
              state = groups[item][name][:state]
              print '  '
              puts "#{name}: #{state}"
              exitcode += 1 unless state == :up
            end
          else
            puts "Task or Group '#{item}' not found."
            exit(1)
          end
        else
          # show all groups and watches
          groups.keys.sort.each do |group|
            puts "#{group}:" unless group.empty?
            groups[group].keys.sort.each do |name|
              state = groups[group][name][:state]
              print '  ' unless group.empty?
              puts "#{name}: #{state}"
            end
          end
        end

        exit(exitcode)
      end

      def signal_command
        # get the name of the watch/group
        name = @args[1]
        signal = @args[2]

        puts "Sending signal '#{signal}' to '#{name}'"

        t = Thread.new do
          loop do
            sleep(1)
            $stdout.print('.')
            $stdout.flush
            sleep(1)
          end
        end

        watches = @server.signal(name, signal)

        # output response
        t.kill
        $stdout.puts
        if watches.empty?
          puts 'No matching task or group'
        else
          puts 'The following watches were affected:'
          watches.each do |w|
            puts "  #{w}"
          end
        end
      end

      def log_command
        Signal.trap('INT') { exit }
        name = @args[1]

        unless name
          puts 'You must specify a Task or Group name'
          exit!
        end

        puts 'Please wait...'
        t = Time.at(0)
        loop do
          print @server.running_log(name, t)
          t = Time.now
          sleep 0.25
        end
      rescue God::NoSuchWatchError
        puts 'No such watch'
      rescue DRb::DRbConnError
        puts 'The server went away'
      end

      def quit_command
        @server.terminate
        abort 'Could not stop god'
      rescue DRb::DRbConnError
        puts 'Stopped god'
      end

      def terminate_command
        t = Thread.new do
          loop do
            $stdout.print('.')
            $stdout.flush
            sleep(1)
          end
        end
        stopped = @server.stop_all
        t.kill
        $stdout.puts
        if stopped
          puts 'Stopped all watches'
        else
          puts "Could not stop all watches within #{@server.terminate_timeout} seconds"
        end

        begin
          @server.terminate
          abort 'Could not stop god'
        rescue DRb::DRbConnError
          puts 'Stopped god'
        end
      end

      def check_command
        Thread.new do
          event_system = God::EventHandler.event_system
          puts "using event system: #{event_system}"

          if God::EventHandler.loaded?
            puts 'starting event handler'
            God::EventHandler.start
          else
            puts '[fail] event system did not load'
            exit(1)
          end

          puts 'forking off new process'

          pid = fork do
            loop { sleep(1) }
          end

          puts "forked process with pid = #{pid}"

          God::EventHandler.register(pid, :proc_exit) do
            puts '[ok] process exit event received'
            exit!(0)
          end

          sleep(1)

          puts 'killing process'

          ::Process.kill('KILL', pid)
          ::Process.waitpid(pid)
        rescue => e
          puts e.message
          puts e.backtrace.join("\n")
        end

        sleep(2)

        puts '[fail] never received process exit event'
        exit(1)
      end

      def lifecycle_command
        # get the name of the watch/group
        name = @args[1]

        puts "Sending '#{@command}' command"

        t = Thread.new do
          loop do
            sleep(1)
            $stdout.print('.')
            $stdout.flush
            sleep(1)
          end
        end

        # send @command
        watches = @server.control(name, @command)

        # output response
        t.kill
        $stdout.puts
        if watches.empty?
          puts 'No matching task or group'
        else
          puts 'The following watches were affected:'
          watches.each do |w|
            puts "  #{w}"
          end
        end
      end
    end
  end
end