require 'date'

class Date
  FOS_JD_OFFSET_DAYS = Date.parse('1899-12-31').jd unless defined?(FOS_JD_OFFSET_DAYS)

  def self.from_fos_days(days)
    self.jd(FOS_JD_OFFSET_DAYS + days)
  end

  def to_fos_days
    jd - FOS_JD_OFFSET_DAYS
  end

  ######## from Ruby Cookbook #########
  def to_gm_time
    to_time_special(new_offset, :gm)
  end

  def to_local_time
    to_time_special(new_offset(DateTime.now.offset-offset), :local)
  end

  private
  def to_time_special(dest, method)
    #Convert a fraction of a day to a number of microseconds
    usec = (dest.send(:sec_fraction) * 60 * 60 * 24 * (10**6)).to_i
    Time.send(method, dest.year, dest.month, dest.day, dest.send(:hour), dest.send(:min), dest.send(:sec), usec)
  end
end

module TimeFunctions
  def as_minutes
    hour*60 + min
  end

  def in_hundredths
    return 0 if hour + min == 0
    minutes = hour*60 + min
    val = "#{minutes/60}.#{((100*(minutes.modulo(60)))/60).to_s.rjust(2, '0')}"
    BigDecimal.new(val, 2).round(2).to_f
  end

  # xos is rounding XOJET STYLE, which is a funky copy of how ipc did it
  def in_hundredths_rounded_xos
    return 0 if hour + min == 0
    # It was determined that "ODD" increments of .05 (ie .15, .35, .55, .75, .95) of an hour (ie. 9,21,33,45,57 minutes) rounded UP whereas even increments of .05 rounded DOWN - sn
    minutes = as_minutes
    (minutes/60.0 + ([9, 21, 33, 45, 57].include?(min) ? 0.001 : -0.001)).round(2)
  end

  # xos is rounding XOJET STYLE, which is a funky copy of how ipc did it
  def in_tenths_rounded_xos
    return 0 if hour + min == 0
    # It was determined that "ODD" increments of .05 (ie .15, .35, .55, .75, .95) of an hour (ie. 9,21,33,45,57 minutes) rounded UP whereas even increments of .05 rounded DOWN - sn
    minutes = as_minutes
    (minutes/60.0 + ([9, 21, 33, 45, 57].include?(min) ? 0.01 : -0.01)).round(1)
  end

  def hm
    strftime("%H:%M")
  end

  def to_fos_days
    to_date.to_fos_days
  end
end

class Time
  include TimeFunctions

  alias :original_to_s :to_s

  def to_s(args=nil)
    return self.strftime('%H:%M') if args == :hm or !args
    self.original_to_s(args)
  end

  # using a date of 2000,1,1 is arbitrary
  def self.from_fos_time(minutes)
    minutes = 0 unless minutes
    Time.utc(2000, 1, 1) + minutes.minutes
  end

  class << self
    alias from_minutes from_fos_time
  end

  ######## from Ruby Cookbook #########
  def to_datetime
    # Convert seconds + microseconds into a fractional number of seconds
    seconds = sec + Rational(usec, 10**6)

    # Convert a UTC offset measured in minutes to one measured in a
    # fraction of a day.
    offset = Rational(utc_offset, 60 * 60 * 24)
    DateTime.new(year, month, day, hour, min, seconds, offset)
  end

  # This is a view "February 01, 2010 01:40" that be parsed directly by javascript
  # ie. in javascript you can say:  Date.parse( "this to long view" )   and you
  # will get a date object
  def long_view
    self.strftime('%B %d, %Y %H:%M')
  end
end

class DateTime
  include TimeFunctions

  # creates utc time from days and minutes
  def self.from_fos_date_time(days, minutes)
    days = 0 unless days
    minutes = 0 unless minutes
    (Date.from_fos_days(days).to_gm_time + minutes.minutes).to_datetime
  end

  def view
    to_s
  end

  # This is a view "February 01, 2010 01:40" that be parsed directly by javascript
  # ie. in javascript you can say:  Date.parse( "this to long view" )   and you
  # will get a date object
  def long_view
    self.strftime('%B %d, %Y %H:%M')
  end

  # Converts self to a Ruby Date object; time portion is discarded
  def to_date
    ::Date.new(year, month, day)
  end unless method_defined?(:to_date)
end