require 'rubygems'
require 'mailfactory'
require 'term/ansicolor'

class String
  include Term::ANSIColor
end

class Abyss
  attr_accessor :daemons, :daemons_alive, :daemons_dead, :interval

  DAEMON_PATH = '/etc/rc.d'
  STATUS_PATH = '/var/run'

  def initialize all_daemons = {}
    @daemons = []
    @interval = 60 * 15 # 15 minutes

    special_cases = {
      'courier-imap' => ['imapd', 'imapd-ssl', 'courier', 'pop3d', 'pop3d-ssl']
    }

    if all_daemons.empty?
      # fetch the list of started daemons from rc.conf
      daemons = File.readlines('/etc/rc.conf').find{|l| l =~ /^DAEMONS/}.chomp
      # get the daemons out of there
      daemons = daemons.scan(/DAEMONS=\((.*?)\)/).first.first
      # get all the daemons and split them into dead and alive ones
      # remove @ if it's there - background-started-processes
      dead, alive = daemons.split.map{|d| d.gsub('@', '')}.partition{|d| d =~ /!/}
      alive = alive.map { |d| special_cases[d].nil? ? d : special_cases[d] }.flatten
      all_daemons = {:alive => alive, :dead => dead}
    end

    all_daemons.each do |state, daemons|
      status = state.to_s.send(state == :dead ? :red : :green)

      daemons.each do |daemon|
        puts "adding daemon [#{status}] #{daemon.inspect}"
        add daemon, state
      end
    end

    puts "#{@daemons.size} Daemons registered:"
    puts "Starting up - Interval every #{@interval} seconds"
    startup
  end

  def startup
    loop do
      Thread.new do
        @daemons.each do |daemon|
          case daemon.should_be
          when :alive
            # puts "#{daemon.name} is #{daemon.is} and should be #{daemon.should_be} [#{daemon.alive?}]"
            daemon.start if daemon.dead?
          when :dead
            daemon.stop if daemon.alive?
          end
        end
        failures = @daemons.find_all { |d| d.failures >= 1 }
        p failures unless failures.empty?
        failures.each do |daemon|
          puts "Found #{daemon} erronous..."
          sendmail daemon
        end
      end
      sleep @interval
    end
  end

  def [](daemon)
    @daemons.find{|d| d.name == daemon.to_sym} || @daemons[daemon]
  end

  def add daemon, state = :alive
    remove daemon
    @daemons << Daemon.new(daemon, state)
  end

  def remove daemon
    @daemons.delete_if{|d| d.name == daemon.to_sym}
  end

  def sendmail daemon
    daemon_inspect = %{
    }
    mail = MailFactory.new
    mail.to = 'm.fellinger@gmail.com'
    mail.from = 'abyss@weez-int.com'
    mail.subject = "[Abyss] Failure - #{daemon.name} - #{daemon.failures} failures"
    mail.text = %{
Houston, we've got a problem

#{daemon.name} is #{daemon.is} and should be #{daemon.should_be} [#{daemon.should_be daemon.should_be}]

The Daemon:
  Name:      #{daemon.name}
  is:        #{daemon.is}
  should be: #{daemon.should_be}
  failures:  #{daemon.failures}
  command:   #{daemon.error[:cmd]}
  the error: #{daemon.error[:returned]}
    }
    sendmail = IO.popen "sendmail #{mail.to}", 'w+'
    sendmail.puts mail.to_s
    sendmail.close
  end
end

class Daemon
  attr_accessor :name, :should_be, :failures, :error

  def initialize name, state = :alive
    @name      = name.to_sym
    @should_be = state
    @failures  = 0
    @error     = nil
  end

  def is
    alive? ? :alive : :dead
  end

  def should_be sym = nil
    sym ? (@should_be == sym) : @should_be
  end

  def alive?
    File.exist? "#{Abyss::STATUS_PATH}/daemons/#{name}"
  end

  def should_be_alive?
    should_be :alive
  end

  def dead?
    !alive?
  end

  def should_be_dead?
    should_be :dead
  end

  def pid
    File.read("#{Abyss::STATUS_PATH}/#{name}.pid").to_i
  end

  def start
    handle :start
  end

  def stop
    handle :stop
  end

  def restart
    handle :restart
  end

  def handle demand
    if [:start, :stop, :restart].include? demand
      puts "#{demand} #{name}"
      cmd = "sudo #{Abyss::DAEMON_PATH}/#{name} #{demand}"
      action = `#{cmd}`.uncolored
      demand_fulfilled = lambda{ demand == :stop ? dead? : alive? }
      if demand_fulfilled.call
        @failures = 0
      else
        @failures += 1
        @error = {:cmd => cmd, :returned => action}
        unless @failures > 3
          puts "#{demand} failed, trying to restart"
          handle :restart
        end
      end
    else
      puts "unknown demand '#{demand}'"
    end
    demand_fulfilled.call
  end
end

Abyss.new