Predict Soccer win streaks

.-soccer-predict

.gitignore

*#*
*~*
.bundle

.ruby-gemset

soccer-predict

.ruby-version

2.6.0

Gemfile

source 'https://rubygems.org'

gem 'nokogiri'
gem 'pry'

Gemfile.lock

GEM
  remote: https://rubygems.org/
  specs:
    coderay (1.1.2)
    method_source (0.9.2)
    mini_portile2 (2.3.0)
    nokogiri (1.8.2)
      mini_portile2 (~> 2.3.0)
    pry (0.12.2)
      coderay (~> 1.1.0)
      method_source (~> 0.9.0)

PLATFORMS
  ruby

DEPENDENCIES
  nokogiri
  pry

BUNDLED WITH
   1.17.3

predict.rb

require 'open-uri'
require 'nokogiri'


# previous_picks = ["Chelsea", 'Tottenham']

# Usage:
# load 'predict.rb'
# p = Predict.new(previous_picks)
# start = Time.now; p.realize_streaks!; Time.now - start
# p.scored_streaks
class Predict
  attr_accessor :teams, :matches, :upcoming_probabilities, :streaks, :scored_streaks, :previous_picks

  def initialize(previous_picks = [])
    @previous_picks = previous_picks
    @matches = matches_node_set.map do |e|
      {
        first_team_name(e) => first_team_prob(e),
        second_team_name(e) => second_team_prob(e)
      }
    end
    @teams = matches_node_set.map { |e| [e['data-team1'], e['data-team2']] }.flatten.uniq - @previous_picks
    @upcoming_probabilities = roi.map { |idx| next_n_matches.map { |ary| ary[idx] }.reduce({}, :merge) }
    @streaks = []
    @scored_streaks = []
    @prediction_weights = prediction_weights
    @evaluated_streaks = {}
  end

  def n
    7
  end

  def evaluate_streaks!(streak)
    score = 0
    evaluated_streak = streak.each_with_index.map do |team, idx|
      team_score = score_team(team, idx)
      score += team_score
      {team => team_score}
    end

    @evaluated_streaks[score] = evaluated_streak
  end

  def realize_streaks!
    puts "Evaluating possible streaks..."
    @teams.permutation(n) { |streak| evaluate_streaks!(streak) }
    puts "Determining top 10 streaks..."
    top_scores = @evaluated_streaks.keys.sort{|a, b| b <=> a}.take(10)
    @scored_streaks = top_scores.map{|k| [k, @evaluated_streaks[k]]}
  end


  def score_team(team, idx)
    score = @upcoming_probabilities[idx][team]
    score * @prediction_weights[idx]
  end

  def roi
    (0...n)
  end

  def prediction_weights
    [1.5, 1.2, 1.2, 1, 1, 1, 1]
  end

  def next_n_matches
    @teams.map do |team|
      @matches.partition { |h| h.keys.include? team }.first[roi]
    end
  end

  def percent_to_float(s)
    s.sub('%', '').to_f / 100
  end

  def first_team_name(match_node)
    match_node.css('tr.match-top').css('td.team')[0]['data-str']
  end

  def first_team_prob(match_node)
    percent_to_float(match_node.css('tr.match-top').css('td.prob')[0].children.text)
  end

  def second_team_name(match_node)
    match_node.css('tr.match-bottom').css('td.team')[0]['data-str']
  end

  def second_team_prob(match_node)
    percent_to_float(match_node.css('tr.match-bottom').css('td.prob')[0].children.text)
  end

  def matches_node_set
    upcoming_games.css('.match-container')
  end

  def url
    'https://projects.fivethirtyeight.com/soccer-predictions/premier-league/'
  end

  def doc
    Nokogiri::HTML(open(url))
  end

  def upcoming_games
    doc.css('.games-container.upcoming')
  end
end