require 'trollop'
require 'resque/pool'

module Resque
  class Pool
    module CLI
      extend self

      def run
        opts = parse_options
        daemonize if opts[:daemon]
        pidfile opts[:pidfile]
        redirect opts
        setup_environment opts
        start_pool
      end

      def parse_options
        opts = Trollop::options do
          version "resque-pool #{VERSION} (c) nicholas a. evans"
          banner <<-EOS
resque-pool is the best way to manage a group (pool) of resque workers

When daemonized, stdout and stderr default to resque-pool.stdxxx.log files in
the log directory and pidfile defaults to resque-pool.pid in the current dir.

Usage:
   resque-pool [options]
where [options] are:
          EOS
          opt :config, "Alternate path to config file",                 :short => "-c"
          opt :daemon, "Run as a background daemon", :default => false, :short => "-d"
          opt :stdout, "Redirect stdout to logfile", :type => String,   :short => '-o'
          opt :stderr, "Redirect stderr to logfile", :type => String,   :short => '-e'
          opt :nosync, "Don't sync logfiles on every write"
          opt :pidfile, "PID file location",         :type => String,   :short => "-p"
          opt :environment, "Set RAILS_ENV/RACK_ENV/RESQUE_ENV", :type => String, :short => "-E"
        end
        if opts[:daemon]
          opts[:stdout]  ||= "log/resque-pool.stdout.log"
          opts[:stderr]  ||= "log/resque-pool.stderr.log"
          opts[:pidfile] ||= "tmp/pids/resque-pool.pid"
        end
        opts
      end

      def daemonize
        raise 'First fork failed' if (pid = fork) == -1
        exit unless pid.nil?
        Process.setsid
        raise 'Second fork failed' if (pid = fork) == -1
        exit unless pid.nil?
      end

      def pidfile(pidfile)
        pid = Process.pid
        if pidfile
          if File.exist? pidfile
            raise "Pidfile already exists at #{pidfile}.  Check to make sure process is not already running."
          end
          File.open pidfile, "w" do |f|
            f.write pid
          end
          at_exit do
            if Process.pid == pid
              File.delete pidfile
            end
          end
        end
      end

      def redirect(opts)
        $stdin.reopen  '/dev/null'        if opts[:daemon]
        $stdout.reopen opts[:stdout], "a" if opts[:stdout] && !opts[:stdout].empty?
        $stderr.reopen opts[:stderr], "a" if opts[:stderr] && !opts[:stderr].empty?
        $stdout.sync = $stderr.sync = true unless opts[:nosync]
      end

      def setup_environment(opts)
        ENV["RACK_ENV"] = ENV["RAILS_ENV"] = ENV["RESQUE_ENV"] = opts[:environment] if opts[:environment]
        puts "Resque Pool running in #{ENV["RAILS_ENV"] || "development"} environment."
        ENV["RESQUE_POOL_CONFIG"] = opts[:config] if opts[:config]
      end

      def start_pool
        require 'rake'
        require 'resque/pool/tasks'
        Rake.application.init
        Rake.application.load_rakefile
        Rake.application["resque:pool"].invoke
      end

    end
  end
end