# The Futures constant is currently for testing purposes. It guesses the front month
# currency future using a crude algorithm that does not take into account expiry/rollover day.
# This will be valid most of the time, but near/after expiry day the next quarter's contract
# takes over as the volume leader.
#
#
# Note that the :description field is particular to ib-ruby, and is NOT part of the standard TWS API.
# It is never transmitted to IB. It's purely used clientside, and you can store any arbitrary string that
# you may find useful there.
#

module IB
  module Symbols

    # Get the next valid quarter month >= today, for finding the
    # front month of quarterly futures.
    #
    # N.B. This will not work as expected near/after expiration during that month, as
    # volume rolls over to the next quarter even though the current month is still valid!
    #
    def self.next_quarter_month(time)
      sprintf("%02d", [3, 6, 9, 12].find { |month| month >= time.month })
    end

    def self.next_quarter_year(time)
      if self.next_quarter_month(time).to_i < time.month
        time.year + 1
      else
        time.year
      end
    end

    def self.next_expiry(time)
      "#{ self.next_quarter_year(time) }#{ self.next_quarter_month(time) }"
    end

    Futures ={
        :ym => Models::Contract.new(:symbol => "YM",
                                    :expiry => self.next_expiry(Time.now),
                                    :exchange => "ECBOT",
                                    :currency => "USD",
                                    :sec_type => SECURITY_TYPES[:future],
                                    :description => "Mini Dow Jones Industrial"),

        :es => Models::Contract.new(:symbol => "ES",
                                    :expiry => self.next_expiry(Time.now),
                                    :exchange => "GLOBEX",
                                    :currency => "USD",
                                    :sec_type => SECURITY_TYPES[:future],
                                    :multiplier => 50,
                                    :description => "E-Mini S&P 500"),

        :gbp => Models::Contract.new(:symbol => "GBP",
                                     :expiry => self.next_expiry(Time.now),
                                     :exchange => "GLOBEX",
                                     :currency => "USD",
                                     :sec_type => SECURITY_TYPES[:future],
                                     :multiplier => 62500,
                                     :description => "British Pounds"),

        :eur => Models::Contract.new(:symbol => "EUR",
                                     :expiry => self.next_expiry(Time.now),
                                     :exchange => "GLOBEX",
                                     :currency => "USD",
                                     :sec_type => SECURITY_TYPES[:future],
                                     :multiplier => 12500,
                                     :description => "Euro FX"),

        :jpy => Models::Contract.new(:symbol => "JPY",
                                     :expiry => self.next_expiry(Time.now),
                                     :exchange => "GLOBEX",
                                     :currency => "USD",
                                     :sec_type => SECURITY_TYPES[:future],
                                     :multiplier => 12500000,
                                     :description => "Japanese Yen"),

        :hsi => Models::Contract.new(:symbol => "HSI",
                                     :expiry => self.next_expiry(Time.now),
                                     :exchange => "HKFE",
                                     :currency => "HKD",
                                     :sec_type => SECURITY_TYPES[:future],
                                     :multiplier => 50,
                                     :description => "Hang Seng Index")
    }
  end
end