solution.rb

# Quiz Exercise, Part One
#
# Quiz for a list of names & birthdays,
# then list out their ages
#
# For example:
#
#   Hey there! Please enter a list of names:
#   > John, Sam, Bob, Alisha, Henry
#
#   Thanks. When is John's birthday? 10/13/2000
#
#   OK, and Sam's birthday? 8/3/1987
#   And Bob's? 2/17/1957
#   Alisha's? 4/21/1978
#   Henry's? 6/23/1980
#
#   OK, all done. You have 5 guests. Here are their ages:
#
#   * John: 13
#   * Sam: 26
#   * Bob: 56
#   * Alisha: 35
#   * Henry: 33
#
#   Enjoy your party!
#



##
## OUTLINE
##

# We're going to want to break the problem down into steps.
# First, let's ask for the user's input:


puts "Hey there! Please enter a list of names:"

guest_names = 'John, Sam, Bob, Alisha, Henry' # TODO: ask for input
# guest_names = gets.chomp



# We want to loop (or iterate) over each name.
# * What type of data do we have in the `guest_names` variable?
# * What type of data supports iteration?
# * How do we transform the first into the second?


list_of_guest_names = guest_names.split(',').map do |name|
  name.strip
end

guests = list_of_guest_names.map do |guest_name|
  guest_birthday     = '10/27/1978' # TODO: ask them their birthday
  is_bringing_a_gift = rand(2).to_i.zero? ? true : false
  how_many_friends   = rand(2).to_i

  age = Time.now.year - guest_birthday.split('/').last.to_i

  {
    :age     => age,  # TODO: calculate this based on their birthday,
    :gift    => is_bringing_a_gift,
    :friends => how_many_friends,
    :name    => guest_name
  }
end

number_of_gifts   = guests.select { |g| g[:gift] }.length
number_of_people  = guests.length + guests.reject do |guest|
  raise 'only 0 or 1 friends' if guest[:friends] > 1

  guest[:friends].zero? # right now they can only bring 1 friend,
                  # if we let them bring more later,
                  # this logic will fail
end.length

# We want to display the data onto the screen.
#
# * How many guests do we have total?
# * What are their names and ages?

puts "All done. You have #{guests.length} guests with friends for a total of #{number_of_people} people."
puts "#{number_of_gifts} of them are bringing gifts."
puts "Here is everyone's ages: "

# TODO: loop over each guest

guests.each do |guest|

  puts "* #{guest[:name]} is #{guest[:age]} years old"

end




##
## EXTENSION #1
##

# Ask for a few more pieces of information:
#
# * Are they bringing a gift? (true or false)
# * Display how many people are bringing a gift.





##
## EXTENSION #2
##

# * How many friends are they bringing? (0, 1)
# * Update the "number of guests" to take the friends' numbers into account:
#
# "You have 5 guests who are bringing 2 friends for a total of 7 people."





##
## EXTENSION #3
##

# Calculate how much the party will cost.
# * Estimate $5 for each person, including the friends that guests are bringing.
# * Add an extra $3 for each person over 21, as they will drink our alcohol
# * Provide a $2 discount for each senior citizen







##
## EXTENSION #4
##

# Display a receipt for the total party cost
# * Display each person as a line-item ($5)
# * Display each alcohol addition
# * Display each discount
# * `rjust` or `ljust` (string methods) each column and value so everything lines up nicely

# EXAMPLE:
# *      Nathaniel:  $5
# *           John:  $5
# *            Sam:  $5
# *   John Alcohol:  $3
# *    Sam Alcohol:  $3
# *    John Senior: ($2)
# *       Subtotal: $19
# *            Tax:  $1.90
# *          Total: $21.90