events.rb

=begin
 Crowdint logical skills test.
=end

require 'rubygems'
require 'faster_csv'

@stats = {}

FasterCSV.foreach("events.csv", :col_sep =>"\t", :headers => :first_row) do |row|
  user = row["user_id"]
  date = row["when"].to_i

  @stats.merge!( user => [{ :start => date, :last => date, :visits => [{:events_per_visit =>0, :visit_duration => 0}] }]) unless @stats.has_key?(user)

  start_time = (date - @stats[user].last[:start] > 3600)
  current_time = (date - @stats[user].last[:last] > 3600)

  @stats[user].last[:visits].last[:events_per_visit] += 1 unless start_time || current_time
  @stats[user].last[:visits].last[:visit_duration] = (date - @stats[user].last[:start]).abs

  if start_time || current_time
    @stats[user].last[:visits].last[:visit_duration] = (@stats[user].last[:last] - @stats[user].last[:start]).abs
    @stats[user].last[:last] = @stats[user].last[:start] = date
    @stats[user].last[:visits] << {:events_per_visit =>1, :visit_duration => 0}
  end

  @stats[user].last[:last] = date
end

pp @stats