class Rufus::Scheduler::ZoTime

def self.envtzable?(s)
  TIMEZONES.include?(s)
end

def self.is_timezone?(str)
  return false if str == nil
  return false if str == '*'
  return false if str.index('#')
    # "sun#2", etc... On OSX would go all the way to true
  return true if Time.zone_offset(str)
  return !! (::TZInfo::Timezone.get(str) rescue nil) if defined?(::TZInfo)
  return true if TIMEZONES.include?(str)
  return true if TIMEZONEs.include?(str)
  t = ZoTime.new(0, str).time
  return false if t.zone == ''
  return false if t.zone == 'UTC'
  return false if t.utc_offset == 0 && str.start_with?(t.zone)
    # 3 common fallbacks...
  return false if RUBY_PLATFORM.include?('java') && ! envtzable?(str)
  true
end

def self.parse(str, opts={})
  if defined?(::Chronic) && t = ::Chronic.parse(str, opts)
    return ZoTime.new(t, ENV['TZ'])
  end
  begin
    DateTime.parse(str)
  rescue
    raise ArgumentError, "no time information in #{o.inspect}"
  end if RUBY_VERSION < '1.9.0'
  zone = nil
  s =
    str.gsub(/\S+/) { |m|
      if envtzable?(m)
        zone ||= m
        ''
      else
        m
      end
    }
  return nil unless zone.nil? || is_timezone?(zone)
  zt = ZoTime.new(0, zone || ENV['TZ'])
  zt.in_zone { zt.seconds = Time.parse(s).to_f }
  zt.seconds == nil ? nil : zt
end

def add(s)
  @seconds += s.to_f
end

def in_zone(&block)
  current_timezone = ENV['TZ']
  ENV['TZ'] = @zone
  block.call
ensure
  ENV['TZ'] = current_timezone
end

def initialize(s, zone)
  @seconds = s.to_f
  @zone = zone
end

def substract(s)
  @seconds -= s.to_f
end

def time
  in_zone do
    t = Time.at(@seconds)
    if t.isdst
      t1 = Time.at(@seconds + 3600)
      t = t1 if t.zone != t1.zone && t.hour == t1.hour && t.min == t1.min
        # ambiguous TZ (getting out of DST)
    else
      t.hour # force t to compute itself
    end
    t
  end
end

def to_f
  @seconds
end

def utc
  time.utc
end