KTH-snittet

kthsnittet.rb

require 'bundler/inline'

gemfile(true) do
  source 'https://rubygems.org'

  gem 'nokogiri', '~> 1.6'
end

require 'csv'
require 'date'
require 'nokogiri'

Result = Struct.new(:code, :name, :credits, :grade, :date)

File.open('resultat.html') do |f|
  doc = Nokogiri::HTML(f)
  clr = doc.at_css('table#courselistresults')

  results = clr.css('tr:not(.grayout):not(.listingHeader)').map do |r|
    next unless r.at_css('td:nth-child(4)').text.empty?

    code = r.at_css('td:nth-child(1)').text
    name = r.at_css('td:nth-child(2)').text
    credits = r.at_css('td:nth-child(3)').text
    grade = r.at_css('td:nth-child(5)').text
    date = r.at_css('td:nth-child(7)').text

    Result.new(code, name, credits.to_f, grade, Date.parse(date))
  end
  results = results.compact.sort_by(&:date)

  CSV.open('snitt.csv', 'w') do |csv|
    csv << ['date', 'gpa']

    numerator = denominator = 0
    results.each do |r|
      next if r.grade == 'P'

      p = case r.grade
          when 'A'
            5
          when 'B'
            4.5
          when 'C'
            4
          when 'D'
            3.5
          when 'E'
            3
          else
            raise ArgumentError.new("Unexpected grade \"#{r.grade}\"")
          end

      numerator += p * r.credits
      denominator += r.credits
      gpa = numerator / denominator

      csv << [r.date, gpa]
    end
  end
end