[selectricity] / app / controllers / graph_controller.rb

# Selectricity: Voting Machinery for the Masses
# Copyright (C) 2007, 2008 Benjamin Mako Hill <mako@atdot.cc>
# Copyright (C) 2007 Massachusetts Institute of Technology
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as
# published by the Free Software Foundation, either version 3 of the
# License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
# Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public
# License along with this program.  If not, see
# <http://www.gnu.org/licenses/>.

require 'date'
class GraphController < ApplicationController  
  class GruffGraff
    
    COLORS = ['#74CE00', '#005CD9', '#DC0D13', '#131313', '#A214A4', '#EFF80E',
              '#90E5E6', '#F58313', '#437D3D', '#0E026C']
    BACKGROUND_COLORS = ['#74CE00', '#FFFFFF'] #for green and white background
    
    def initialize(options)
      size = options[:size] ? options[:size] : "400x300" #allow custom sizing
      @graph = options[:graph_type].new(size)
      
      @graph.no_data_message = "No Voters"
      
      @graph.theme = { :colors => COLORS,
                       :background_colors => ['#e5e5e5', '#FFFFFF']  }
      @graph.font = File.expand_path('/usr/X11R6/lib/X11/fonts/TTF/Vera.ttf',
                                   RAILS_ROOT)
      
      if options[:legend_font_size]
        @graph.legend_font_size = options[:legend_font_size] 
      end
      
      if options[:title_font_size]  
        @graph.title_font_size = options[:title_font_size]
      end
      
      #marker count doesn't include minimum value line, default is 4
      @graph.marker_count = options[:marker_count] if options[:marker_count]
      
      @graph.marker_font_size = options[:marker_font_size] if options[:marker_font_size]
      
      @graph.marker_color = options[:marker_color] if options[:marker_color]
      
      # fill in the data with the optional data name
      #Check to see if multiple datasets, if so, fill them all!
      #Sort by biggest first piece of data.
      if options[:data].is_a?(Hash) 
        options[:data].sort {|a,b| b[1][0] <=> a[1][0]}.each do |dataset|
          @graph.data(dataset[0], dataset[1])
        end
      #if each dataset nameless, will have only multiple arrays    
      elsif options[:data].size > 1 && options[:data].all?  {|i| i.is_a?(Array)}
        options[:data].each do |array|
          @graph.data( options.fetch(:data_name, "Data"), array)
        end
      else #one dimensional array, just pass it in
      @graph.data( options.fetch(:data_name, "Data"), options[:data] )
      @graph.hide_legend = true
      end
      
      # set the labels or create an empty hash
      @graph.labels = options[:interval_labels] \
        if options.has_key?(:interval_labels) and \
           options[:interval_labels].class == Hash
      @graph.x_axis_label = options[:x_axis_label] \
        if options.has_key?(:x_axis_label)
      @graph.y_axis_label = options[:y_axis_label] \
        if options.has_key?(:y_axis_label)
      @graph.title = options[:title] if options.has_key?(:title)
      
      @graph.minimum_value = 0.0

    end

    def output
      return([@graph.to_blob, {:disposition => 'inline', :type => 'image/png'}])
    end

  end

  # produce a graph of votes per day during an election
  def votes_per_day
    @election = Election.find(params[:id])
    data, labels = get_votes_per_day_data(@election)
    
    graph = GruffGraff.new( :graph_type => Gruff::Line,
                            :data_name => @election.name,
                            :data => data,
                            :interval_labels => labels,
                            :title => "Voters Per Day",
                            :x_axis_label => "Data",
                            :y_axis_label =>"Number of Votes")
    send_data(*graph.output)
  end
  
  #will place votes in a fixed number of intervals, and shows votes over time
  def votes_per_interval
    @election = Election.find(params[:id])
    data, labels, scale = get_votes_per_interval_data(@election)
    
    hide_legend = true
    
    graph = GruffGraff.new( :graph_type => Gruff::Line,
                            :data_name => @election.name,
                            :data => data,
                            :interval_labels => labels,
                            :title => "Voters Over Time",
                            :size => "330x232", 
                            :legend_font_size => 40,
                            :title_font_size => 50,
                            :marker_count => 2,
                            :marker_font_size => 30,
                            :marker_color => '#999999',
                            :x_axis_label => scale,
                            :y_axis_label => "Number of Votes")
    send_data(*graph.output)
  end
  
  def borda_bar
    @election = Election.find(params[:id])
    @election.results unless @election.borda_result
    data, labels = get_borda_points(@election.borda_result)
    
    size = "400x300"
    size = "580x300" if @election.candidates.size >= 5
    
   if @election.candidates.size >= 5
     marker_font_size = 17
   else
     marker_font_size = 20
   end
    
    graph = GruffGraff.new( :graph_type => Gruff::Bar,
                            :data_name => @election.name,
                            :data => data,
                            :interval_labels => labels,
                            :size => size,
                            :title => "Points Per Candidate",
                            :marker_color => '#999999',
                            :marker_font_size => marker_font_size,
                            :y_axis_label => "Points",
                            :x_axis_label => "Candidates")
    send_data(*graph.output)
  end
  #Acording to Tufte, small, concomparitive, highly labeled data sets usually
  #belong in tables. The following is a bar graph...but would it be better
  #as a table?
  def choices_positions
    @election = Election.find(params[:id])
    legend = Hash.new   
    alldata, labels = get_positions_info(@election)    
    @election.results unless @election.condorcet_result || @election.ssd_result
    ranked_candidates = @election.condorcet_result.ranked_candidates.flatten
    
    names = Hash.new
    candidates = @election.candidates.sort.collect {|candidate| candidate.id}
    candidates.each do |candidate|
      names[candidate]= (Candidate.find(candidate)).name
    end
    
    ranked_candidates.each_with_index \
    {|candidate, index| legend[names[candidate]] = alldata[index]}
    
    graph = GruffGraff.new( :graph_type => Gruff::Bar,
                            :data => legend,
                            :interval_labels => labels,
                            :title => "Times Voted in Each Position",
                            :y_axis_label => "Number of Times Ranked",
                            :x_axis_label => "Rank")
    send_data(*graph.output) 
  end
  
  def plurality_pie
    @election = Election.find(params[:id])
    @election.results unless @election.plurality_result || @election.approval_result
    votes = @election.votes.size
    data = Hash.new
    names = @election.names_by_id
    
    @election.plurality_result.points.each do |candidate, votes|
      data[names[candidate]] = votes
    end
    size = "400x300"
    size = "520x300" if @election.candidates.size >= 8

   if @election.candidates.size >= 8
     marker_font_size = 20
     legend_font_size = 17
   else
     marker_font_size = 17
     legend_font_size = 17
   end
 
    pie = GruffGraff.new( :graph_type => Gruff::Pie,
                           :title => "Percentage of First Place Votes",
                           :size => size,
                           :marker_font_size => marker_font_size,
                           :legend_font_size => legend_font_size,
                           :data => data)
    send_data(*pie.output)
                           
  end
  
 private 
  def get_positions_info(election)
    buckets = Hash.new
    buckets2= Hash.new
    rank_labels = Hash.new
    
    #attach the ranking to the candidate's array to which is belongs
    #creating a key if necessary
    election.votes.each do |vote|
      vote.rankings.each do |ranking|
        
         unless buckets.has_key?(ranking.candidate_id)
           buckets[ranking.candidate_id] = []
         end
        buckets[ranking.candidate_id] << ranking.rank
        
      end
    end
    
    #count how many times each candidate has been ranked at a certain level
    buckets.each_pair do |id, array|
      (1..election.candidates.size).each do |i|
        buckets2[id] = [] unless buckets2.has_key?(id)
        buckets2[id] << (array.find_all {|rank| rank == i}).size
      end
    end
    
    #sort by amount of 1st place votes
    sorted_data = buckets2.values.sort {|a,b| b[0] <=> a[0]}
    
    election.votes.each do |vote|
      vote.rankings.size.times do |i|
        rank_labels[i] = (i+1).to_s
      end
    end
    
    return sorted_data, rank_labels   
  end
   
  # generate the data and labels for each graph
  def get_votes_per_day_data(election)
    voter_days = Array.new
    unique_days = Array.new
    total_per_day = Array.new
    election_days = Hash.new
    
    #turn election startdate into date object, and create the range of election
    startdate = Date.parse(election.startdate.to_s)
    election_range = startdate..Date.today
    
    # create a hash with all the dates of the election in String format
    # referenced by their order in the election
    election_range.each_with_index do |day, index|
      election_days[index] = day.to_s
    end
    
    # Now I need to create an array with all the times votes were made
    election.votes.each do |vote|
      next unless vote.time
      voter_days << Date.parse(vote.time.to_s)
    end
    voter_days.sort!
    
    # Now I need to count how many times each each date appears in voter_days,
    # and put that number into a votes_per_day array, the 'data' for the graph    
    #Create an array of unique days from voter_days
    voter_days.each do |day|
      unless unique_days.any? {|date| date.eql?(day)}
        unique_days << day
      end
    end
    unique_days.sort!
    
    #find all dates where those days = date at current index, put size of returned
    #array into total_per_day
    unique_days.each_with_index do |date, index|
      total_per_day << (voter_days.select {|day| day.eql?(date)}).size
    end    

    # return the data and the labels
    return total_per_day, election_days
   
  end
  
  def get_votes_per_interval_data(election)
    labels_hash = Hash.new
    buckets = Hash.new
    total_per_interval = Array.new
    interval_type = ""
    
    starttime = election.startdate
    timedelta = Time.now - starttime
    numcols = 10
    interval_length = timedelta/numcols
    
    # Make a hash, buckets, indexed by time intervals and containing empty arrays
    # The time object must come first in addition! 
    # i would start at 0, i+1 goes from 1 up till numcols
    numcols.times {|i| buckets[starttime + ((i+1)*interval_length)] = []}
     
    # Put votes into bucket according to the time interval to which they belong,
    # referenced by their key
    # Will build a graph over time, as each successive interval will have more
    # vote objects  
    election.votes.each do |vote|
      next unless vote.time
      buckets.keys.sort.each do |inter|
        if vote.time < inter
          buckets[inter] << vote
        end
      end
    end
  
    total_per_interval = buckets.keys.sort.collect {|key| buckets[key].size}
    
    # Create the hash for the labels. Each graph has ten columns, and three
    # will be labeled
    if timedelta < 2.hours #under two hours use minutes for labels
      labels_hash[0] = "Start"
      labels_hash[(numcols/2)-1] = fmt_decimal((timedelta/120)) #halfway
      labels_hash[numcols-1] = fmt_decimal((timedelta/60))
      interval_type = "Minutes After Start"
    elsif timedelta < 2.days #more than 2 hours means use hours for labels
      labels_hash[0] = "Start"
      labels_hash[(numcols/2)-1] = fmt_decimal((timedelta/7200))
      labels_hash[numcols-1] = fmt_decimal((timedelta/3600))
      interval_type = "Hours After Start (Up to 48)"
    else #more than 2 days means use dates for labels
      labels_hash[0] = (Date.parse(starttime.to_s)).to_s
      labels_hash[(numcols/2)-1] = (Date.parse((starttime + (timedelta/2)).to_s)).to_s
      labels_hash[numcols-1] = (Date.today).to_s
      interval_type = "The Date"
    end
    
    # Make sure to return an array for data and hash for labels
    return total_per_interval, labels_hash, interval_type   
  end
  
  def fmt_decimal(number)
    sprintf( "%0.1f", number)
  end
  
  def get_borda_points(result)
    points = Array.new
    labels = Hash.new

    #Populate points with an sorted array from election.votes hash
    #biggest to smallest will go from left to right
    points = result.points.sort do |a, b|
      b[1] <=> a[1]
    end.collect {|i| i[1]}

    #make the labels  
    result.ranked_candidates.each_with_index do |candidate, index|
      labels[index] = Candidate.find(candidate).name
    end

    return points, labels
  end

  #most vote result objects require an array of vote arrays, which this will make
  def make_preference_tally(election)
    preference_tally = Array.new
    @election.voters.each do |voter|
      next unless voter.voted?
      preference_tally << voter.vote.rankings.sort.collect \
        { |ranking| ranking.candidate.id }
    end
  return preference_tally
  end
end