ARTICLES WE HAVE PUBLISHED

Business Hours #10

Last month I participated in the Ruby Programming Challenge #10 by Ryan Bates over on the Ruby Learning Blog. It was a great experience and I learned a lot just by working on this small exercise.

You can read more about the problem as presented by Ryan at the link above. It’s interesting to see all the various solutions people come up with - Below is my solution to the problem:

# Eric Hutzelman
# Ruby Challenge 10 (Business Hours)
# http://rubylearning.com/blog/2010/05/25/rpcfn-business-hours-10/
#
# Stores all exception days in a hash (@modified_days) and uses array
# method to retrieve the time range for any given date.
# Method #calculate_deadline is recursive and applies the available
# seconds for each date to the time required, stepping forward one day
# at a time until the required seconds have been fulfilled.

require 'time'
require 'date'

class Time
  def to_date
    Date.new(year, month, day)
  end
end

class BusinessHours

  def initialize(time_in, time_out)
    @default_range = TimeRange.new(time_in, time_out)
    @modified_days = {}
  end

  def update(day, time_in, time_out)
    key = day.is_a?(Symbol) ? day : Date.parse(day)
    @modified_days[key] = TimeRange.new(time_in, time_out)
  end

  def closed(*days)
    days.each {|day| update(day, '0:00', '0:00')}
  end

  def [](date)
    day_of_week = date.strftime("%a").downcase.to_sym
    range = @modified_days[date] || @modified_days[day_of_week] || @default_range
    # reset time range dates to match date param
    range.reset_date(date)
    range
  end

  def calculate_deadline(seconds, start_time)
    start_time = Time.parse(start_time)
    range = self[start_time.to_date]

    if range.applies?(start_time)
      start_time = [start_time, range.start].max
      available_seconds = range.stop - start_time

      return start_time + seconds if available_seconds > seconds
      seconds -= available_seconds
    end

    calculate_deadline(seconds, (start_time.to_date + 1).to_s)
  end

end

class TimeRange

  def initialize(time_in, time_out)
    @range = Time.parse(time_in)..Time.parse(time_out)
  end

  def reset_date(date)
    @range = Time.local(date.year, date.month, date.day, start.hour, start.min)..
      Time.local(date.year, date.month, date.day, stop.hour, stop.min)
  end

  def applies?(time)
    stop > time
  end

  def stop
    @range.end
  end

  def start
    @range.begin
  end

end