require 'date'
require 'astro/moon'

class MoonPlugin < Plugin
  def help(plugin, topic="")
    "moon => shows the phase of the moon; moon on => announce full/new moon; moon off => don't announce full/new moon"
  end

  def initialize(*a)
    super
    @timers = Array.new
    self.init_timers
  end

  def init_timers
    now = DateTime.now
    ph = Astro::Moon.phasehunt
    add_timers(ph.moon_start, 'New', now)
    add_timers(ph.moon_full, 'Full', now)
    add_timers(ph.moon_end, 'New', now)
  end

  def add_timers(date, msg, now)
    [
      [-12 * 3600, "Be advised, #{msg} Moon tonight!"],
      [-15 * 60, "Be advised, #{msg} Moon in 15 minutes!"],
      [0, "The Moon is #{msg} *NOW*!"],
      [12 * 3600, "#{msg} Moon is over (12 hours ago)"]
    ].each do |_|
      delta = ((date - now) * 86400).to_i + _[0]
      next if delta <= 0
      @timers.push @bot.timer.add_once(delta) {
        self.announce(_[1])
        @timers.shift or self.init_timers
      }
    end
  end

  def cleanup(*a)
    super
    @timers.each { |_| @bot.timer.remove(_) }
  end

  def announce(msg)
    @registry['clients'].each_key { |c| @bot.say(c, msg) }
  end

  def p2s(p)
    case p
    when 0.00 .. 0.01
          'New (%.2f%%)'
    when 0.24 .. 0.26
          'First Quarter (%.2f%%)'
    when 0.49 .. 0.51
          'Full (%.2f%%)'
    when 0.74 .. 0.76
          'Last Quarter (%.2f%%)'
    when 0.99 .. 1.0
          'New (%.2f%%)'
    when 0.0 .. 0.25
          'Waxing Crescent (%.2f%% Full)'
    when 0.25 .. 0.5
          'Waxing Gibbous (%.2f%% Full)'
    when 0.5 .. 0.75
          'Waning Gibbous (%.2f%% Full)'
    else
          'Waning Crescent (%.2f%% Full)'
    end
  end

  def human_delta(dt)
    d = dt - DateTime.now
    return '' if d < -1 || d > 1
    d = (d * 86400).to_i
    return "(*NOW*!)" if d > -60 && d < 60
    fmt = " \002(in %s)\002"
    if d < 0
      d = -d
      fmt = " \002(%s ago)\002"
    end
    s = Time.at(d).utc.strftime(' %Hh %Mm %Ss')
    s.gsub!(/ 0/, ' ')
    s.gsub!(/ 0./, '')
    s.sub!(/^ /, '')
    fmt % s
  end

  def moon(m, params)
    begin
      p = Astro::Moon.phase
      ph = Astro::Moon.phasehunt
      s = ("moon age is %.1f, the moon is " + p2s(p.phase)) %
        [p.age, p.illumination * 100]
      s << ". last new moon: #{ph.moon_start.strftime('%b %d %Y, %H:%M')}"
      s << human_delta(ph.moon_start)
      s << ", full moon: #{ph.moon_full.strftime('%b %d %Y, %H:%M')}"
      s << human_delta(ph.moon_full)
      s << ", next new moon: #{ph.moon_end.strftime('%b %d %Y, %H:%M')}"
      s << human_delta(ph.moon_end)
      m.reply s
    rescue Exception => e
      m.reply "error: #{e.message}"
      error e.backtrace.join("\n")
    end
  end

  def moon_on(m, params)
    on = nil
    target = m.private? ? m.sourcenick : m.channel.to_s
    clients = @registry['clients'] || Hash.new

    if params[:on] =~ /^(on|yes|true)$/i
      on = true
      clients[target] = true
    elsif params[:on] =~ /^(off|no|false)$/i
      on = false
      clients.delete(target)
    else
      on = clients[target]
      m.reply "should be 'on' or 'off' (#{on ? 'on' : 'off'} for #{target})"
      return
    end
    @registry['clients'] = clients
    m.reply "moon phases will#{on ? '' : ' not'} be announced to #{target}"
  end
end

plugin = MoonPlugin.new
plugin.map 'moon'
plugin.map 'moon :on', :action => 'moon_on'