Thinkful | Ruby on Rails | Tip Calculator Part 5

tip_calculator5.rb

require "optparse" 


def calculate_rate(base, percentage)
    return base * percentage/100
end

def calculate_meal_costs(meal_base, tax_rate, tip_rate)
    tax_value = calculate_rate(meal_base, tax_rate)
    meal_with_tax = tax_value + meal_base
    tip_value = calculate_rate(meal_with_tax, tip_rate)
    total = meal_with_tax + tip_value
    meal_info = {:meal_base => meal_base,
                :tax_rate => tax_rate,
                :tax_value => tax_value,
                :tip_rate => tip_rate,
                :tip_value => tip_value,
                :total  =>  total}
    return meal_info
end

options = {}
optparse = OptionParser.new do |opts|
    opts.on("-m", "--meal MEAL", Float, 
            "raw meal cost as integer or float") do |meal|
        options[:meal] = meal
    end
    opts.on("-x", "--tax TAX", Float, 
            "tax percent as integer or float") do |tax|
        options[:tax] = tax
    end
    opts.on("-t", "--tip TIP", Float, 
            "tip percent as integer or float") do |tip|
        options[:tip] = tip
    end
end

begin
  optparse.parse!
  mandatory = [:meal, :tax, :tip]
  missing = mandatory.select{ |param| options[param].nil? }
  if not missing.empty?
    puts "Missing inputs: #{missing.join(', ')}"
    puts optparse
    exit
  end
rescue OptionParser::InvalidOption, OptionParser::MissingArgument
  puts $!.to_s
  puts optparse
  exit
end

meal_info = calculate_meal_costs(options[:meal], options[:tax], options[:tip])

print "The pre-tax cost of your meal was $%.2f.\n" % meal_info[:meal_base]
print "At %d%%, tax for this meal is $%.2f.\n" % [meal_info[:tax_rate], meal_info[:tax_value]]
print "For a %d%% tip, you should leave $%.2f.\n" % [meal_info[:tip_rate], meal_info[:tip_value]]
print "The grand total for this meal is then $%.2f.\n" % meal_info[:total]