Please help me with this Ruby code

Question

Hi,

I am new to Ruby and I know that I am not using the simple and powerful methods available within it. I made my code work but it has to be simple not this huge (especially I feel I am very bad at loop variables)

i = 0
j = 0

loop_count = ((to_date-from_date)/(60*60*24)).to_i#diff b/w two dates in days

loop_count.times do
   48.times do

    event = Icalendar::Event.new

    status = get_availability_on_date_and_hour(@templates, @availabilities, from_date+j.days, i).downcase

    if(status != 'unavailable')
      #Initialize start and end dates in DateTime's civil format
      bias_date_time = DateTime.civil(from_date.year, from_date.month, from_date.day)

      event.dtstart = bias_date_time + j.day + (i/2).to_i.hour + (i%2*30).to_i.minutes
      event.dtend = event.dtstart + 30.minutes

      event.summary = status.upcase
      cal.add_event(event)
    end

    i += 1
  end
  i = 0
  j += 1
end

Answer 1

You can get rid of the initializing and incrementing of the counter variables i and j like this:

0.upto(((to_date-from_date)/(60*60*24)).to_i) do |j|
  0.upto(48) do |i|
    event = Icalendar::Event.new

    status = get_availability_on_date_and_hour(@templates, @availabilities, from_date+j.days, i).downcase

    if(status != 'unavailable')
      #Initialize start and end dates in DateTime's civil format
      bias_date_time = DateTime.civil(from_date.year, from_date.month, from_date.day)

      event.dtstart = bias_date_time + j.day + (i/2).to_i.hour + (i%2*30).to_i.minutes
      event.dtend = event.dtstart + 30.minutes

      event.summary = status.upcase
      cal.add_event(event)
    end
  end
end

This code is 6 lines shorter than yours, can't do anything about the code within the loops, because I don't really understand what you're doing there.

Update: An Alternative that works too:

((to_date-from_date)/(60*60*24)).to_i.times do |j|
  48.times do |i|
    event = Icalendar::Event.new

    status = get_availability_on_date_and_hour(@templates, @availabilities, from_date+j.days, i).downcase

    if(status != 'unavailable')
      #Initialize start and end dates in DateTime's civil format
      bias_date_time = DateTime.civil(from_date.year, from_date.month, from_date.day)

      event.dtstart = bias_date_time + j.day + (i/2).to_i.hour + (i%2*30).to_i.minutes
      event.dtend = event.dtstart + 30.minutes

      event.summary = status.upcase
      cal.add_event(event)
    end
  end
end

Answer 2

Nothing particularly Ruby specific, but in general keep your methods short..

I would extract the loop contents into a separate method. The method name is used to describe what is going on.

I would also extract the calculation into a separate method to describe what it is you are trying to do and keep the complicated bits (the parts most likely to need changing) separate..

Something like :

0.upto(((to_date-from_date)/(60*60*24)).to_i) do |j|
  0.upto(48) do |i|
      status = get_availability_on_date_and_hour(@templates, @availabilities, from_date+j.days, i).downcase

      add_event(from_date, to_date, i, j, status) if status != 'unavailable'
  end
end


def add_event(from_date, to_date, i, j, status)
      event = Icalendar::Event.new

      event.dtstart = whatever_i_am_trying_to_calculate(from_date, i, j)
      event.dtend = event.dtstart + 30.minutes
      event.summary = status.upcase

      cal.add_event(event)
end

def whatever_i_am_trying_to_calculate(from_date, i, j)
  bias_date_time = DateTime.civil(from_date.year, from_date.month, from_date.day)
  bias_date_time + j.day + (i/2).to_i.hour + (i%2*30).to_i.minutes
end

Also give your variables i and j useful names. i and j don't mean very much.

Answer 3

We can get rid of the j variable and avoid addition of j.days everywhere and use date

from_date.to_i.step(to_date.to_i, 24*60*60) do |date|
  0.upto(48) do |half_hour|
    each_date = Time.at(date)
    event = Icalendar::Event.new

    status = get_availability_on_date_and_hour(@templates, @availabilities, each_date, half_hour).downcase

    if(status != 'unavailable')
      #Initialize start and end dates in DateTime's civil format

      bias_date_time = DateTime.civil(each_date.year, each_date.month, each_date.day)

      event.dtstart = bias_date_time + (i/2).to_i.hour + (i%2*30).to_i.minutes
      event.dtend = event.dtstart + 30.minutes

      event.summary = status.upcase
      cal.add_event(event)
    end
  end
end