module EtOrbi

  @chronic_enabled = true
    #
  def self.chronic_enabled?
    @chronic_enabled
  end
  def self.chronic_enabled=(b)
    @chronic_enabled = b
  end

  class << self

    def now(zone=nil)

      EoTime.new(Time.now.to_f, zone)
    end

    def parse(str, opts={})

      str, str_zone = extract_zone(str)

      if t = chronic_parse(str, opts)
        str = [ t.strftime('%F %T'), str_zone ].compact.join(' ')
      end

      dt =
        begin
          DateTime.parse(str)
        rescue
          fail ArgumentError, "No time information in #{str.inspect}"
        end
        #end if RUBY_VERSION < '1.9.0'
        #end if RUBY_VERSION < '2.0.0'
          #
          # is necessary since Time.parse('xxx') in Ruby < 1.9 yields `now`

      zone =
        opts[:zone] ||
        get_tzone(str_zone) ||
        determine_local_tzone

      #local = Time.parse(str)
      #secs = zone.local_to_utc(local).to_f
      secs = zone.local_to_utc(dt).to_time.to_f

      EoTime.new(secs, zone)
    end

    def make_time(*a)

      zone = a.length > 1 ? get_tzone(a.last) : nil
      a.pop if zone

      o = a.length > 1 ? a : a.first

      case o
      when Time then make_from_time(o, zone)
      when Date then make_from_date(o, zone)
      when Array then make_from_array(o, zone)
      when String then make_from_string(o, zone)
      when Numeric then make_from_numeric(o, zone)
      when ::EtOrbi::EoTime then make_from_eotime(o, zone)
      else fail ArgumentError.new(
        "Cannot turn #{o.inspect} to a ::EtOrbi::EoTime instance")
      end
    end
    alias make make_time

    protected

    def chronic_parse(str, opts)

      return false unless defined?(::Chronic)
      return false unless opts.fetch(:enable_chronic) { self.chronic_enabled? }

      os = opts
        .select { |k, _| Chronic::Parser::DEFAULT_OPTIONS.keys.include?(k) }

      ::Chronic.parse(str, os)
    end

    def make_from_time(t, zone)

      z =
        zone ||
        get_as_tzone(t) ||
        get_local_tzone(t) ||
        get_tzone(t.zone)

      z ||= t.zone
        # pass the abbreviation anyway,
        # it will be used in the resulting error message

      EoTime.new(t, z)
    end

    def make_from_date(d, zone)

      make_from_time(
        d.respond_to?(:to_time) ?
        d.to_time :
        Time.parse(d.strftime('%Y-%m-%d %H:%M:%S')),
        zone)
    end

    def make_from_array(a, zone)

      parse(
        Time.utc(*a).strftime('%Y-%m-%d %H:%M:%S.%6N'), # not a Chronic string
        zone: zone, enable_chronic: false)
    end

    def make_from_string(s, zone)

      parse(s, zone: zone)
    end

    def make_from_numeric(f, zone)

      EoTime.new(Time.now.to_f + f, zone)
    end

    def make_from_eotime(eot, zone)

      return eot if zone == nil || zone == eot.zone
      EoTime.new(eot.to_f, zone)
    end
  end
end