Display only existing stats

So if we don't have information regarding gender, age or geozone, stats
regarding those topics will not be shown.

Note we're using `spec/models/statisticable_spec.rb` because having the
same file in `spec/models/concerns` caused the tests to be executed
twice.

Also note the implementation behind the `gender?`, `age?` and `geozone?`
methods is a bit primitive. We might need to make it more robust in the
future.

app/models/concerns/statisticable.rb

@@ -1,5 +1,6 @@
 module Statisticable
   extend ActiveSupport::Concern
+  PARTICIPATIONS = %w[gender age geozone]
 
   included do
     attr_reader :resource
@@ -9,7 +10,27 @@ module Statisticable
     end
 
     def generate
-      self.class.stats_methods.each { |stat_name| send(stat_name) }
+      stats_methods.each { |stat_name| send(stat_name) }
+    end
+
+    def stats_methods
+      base_stats_methods + participation_methods
+    end
+
+    def participations
+      PARTICIPATIONS.select { |participation| send("#{participation}?") }
+    end
+
+    def gender?
+      participants.male.any? || participants.female.any?
+    end
+
+    def age?
+      participants.between_ages(age_groups.flatten.min, age_groups.flatten.max).any?
+    end
+
+    def geozone?
+      participants.where(geozone: geozones).any?
     end
 
     def total_male_participants
@@ -66,6 +87,14 @@ module Statisticable
 
     private
 
+      def base_stats_methods
+        self.class.base_stats_methods
+      end
+
+      def participation_methods
+        participations.map { |participation| self.class.send("#{participation}_methods") }.flatten
+      end
+
       def total_participants_with_gender
         participants.where.not(gender: nil).distinct.count
       end
@@ -115,10 +144,28 @@ module Statisticable
 
   class_methods do
     def stats_methods
-      %i[total_participants
+      base_stats_methods + gender_methods + age_methods + geozone_methods
-         total_male_participants total_female_participants total_unknown_gender_or_age
+    end
-         male_percentage female_percentage
+
-         participants_by_age participants_by_geozone]
+    def base_stats_methods
+      %i[total_participants participations] + participation_check_methods
+    end
+
+    def participation_check_methods
+      PARTICIPATIONS.map { |participation| :"#{participation}?" }
+    end
+
+    def gender_methods
+      %i[total_male_participants total_female_participants total_unknown_gender_or_age
+         male_percentage female_percentage]
+    end
+
+    def age_methods
+      [:participants_by_age]
+    end
+
+    def geozone_methods
+      [:participants_by_geozone]
     end
 
     def stats_cache(*method_names)

app/views/budgets/stats/show.html.erb

@@ -40,7 +40,7 @@
 
   <div class="row margin">
     <div class="small-12 medium-3 column sidebar">
-      <%= render "shared/stats/links" %>
+      <%= render "shared/stats/links", stats: @stats %>
 
       <p><strong><%= link_to t("stats.advanced"), "#advanced_statistics" %></strong></p>
       <ul class="menu vertical">

app/views/polls/stats.html.erb

@@ -7,7 +7,7 @@
 
   <div class="row margin">
     <div class="small-12 medium-3 column sidebar">
-      <%= render "shared/stats/links" %>
+      <%= render "shared/stats/links", stats: @stats %>
 
       <p><strong><%= link_to t("stats.advanced"), "#advanced_statistics" %></strong></p>
       <ul class="menu vertical">

app/views/shared/stats/_age.html.erb

@@ -0,0 +1,28 @@
+<div id="participants_by_age" class="stats-group">
+  <h4><%= t("stats.by_age") %></h4>
+
+  <table>
+    <thead>
+      <tr>
+        <th class="small-4"><%= t("stats.age") %></th>
+        <th><%= t("stats.total") %></th>
+      </tr>
+    </thead>
+
+    <tbody>
+      <% stats.participants_by_age.values.each do |group| %>
+        <tr>
+          <td><%= group[:range] %></td>
+          <td>
+            <strong>
+              <%= "#{group[:count]} (#{number_to_stats_percentage(group[:percentage])})" %>
+            </strong>
+            <div class="progress" tabindex="0">
+              <span class="progress-meter" style="width: <%= group[:percentage] %>%"></span>
+            </div>
+          </td>
+        </tr>
+      <% end %>
+    </tbody>
+  </table>
+</div>

app/views/shared/stats/_gender.html.erb

@@ -0,0 +1,15 @@
+<div id="participants_by_gender" class="stats-group">
+  <h4><%= t("stats.by_gender") %></h4>
+
+  <%= number_with_info_tags(
+    stats.total_male_participants,
+    t("stats.men_percentage", percentage: number_to_stats_percentage(stats.male_percentage)),
+    html_class: "participants male"
+  ) %>
+
+  <%= number_with_info_tags(
+    stats.total_female_participants,
+    t("stats.women_percentage", percentage: number_to_stats_percentage(stats.female_percentage)),
+    html_class: "participants female"
+  ) %>
+</div>

app/views/shared/stats/_geozone.html.erb

@@ -0,0 +1,23 @@
+<div id="participants_by_geozone" class="stats-group">
+  <h4><%= t("stats.by_geozone") %></h4>
+
+  <table>
+    <thead>
+      <tr>
+        <th><%= t("stats.geozone") %></th>
+        <th><%= t("stats.total") %></th>
+        <th><%= t("stats.geozone_participation") %></th>
+      </tr>
+    </thead>
+
+    <tbody>
+      <% stats.participants_by_geozone.each do |geozone, participants| %>
+        <tr>
+          <td><%= geozone %></td>
+          <td><%= "#{participants[:total][:count]} (#{number_to_stats_percentage(participants[:total][:percentage])})" %></td>
+          <td><%= number_to_stats_percentage(participants[:percentage]) %></td>
+        </tr>
+      <% end %>
+    </tbody>
+  </table>
+</div>

app/views/shared/stats/_links.html.erb

@@ -3,13 +3,10 @@
   <li>
     <%= link_to t("stats.total_participants"), "#total_participants" %>
   </li>
-  <li>
+
-    <%= link_to t("stats.by_gender"), "#participants_by_gender" %>
+  <% stats.participations.each do |stat| %>
-  </li>
+    <li>
-  <li>
+      <%= link_to t("stats.by_#{stat}"), "#participants_by_#{stat}" %>
-    <%= link_to t("stats.by_age"), "#participants_by_age" %>
+    </li>
-  </li>
+  <% end %>
-  <li>
-    <%= link_to t("stats.by_geozone"), "#participants_by_geozone" %>
-  </li>
 </ul>

app/views/shared/stats/_participation.html.erb

@@ -11,73 +11,7 @@
     ) %>
   </div>
 
-  <div id="participants_by_gender" class="stats-group">
+  <% stats.participations.each do |participation| %>
-    <h4><%= t("stats.by_gender") %></h4>
+    <%= render "shared/stats/#{participation}", stats: stats %>
-
+  <% end %>
-    <%= number_with_info_tags(
-      stats.total_male_participants,
-      t("stats.men_percentage", percentage: number_to_stats_percentage(stats.male_percentage)),
-      html_class: "participants male"
-    ) %>
-
-    <%= number_with_info_tags(
-      stats.total_female_participants,
-      t("stats.women_percentage", percentage: number_to_stats_percentage(stats.female_percentage)),
-      html_class: "participants female"
-    ) %>
-  </div>
-
-  <div id="participants_by_age" class="stats-group">
-    <h4><%= t("stats.by_age") %></h4>
-
-    <table>
-      <thead>
-        <tr>
-          <th class="small-4"><%= t("stats.age") %></th>
-          <th><%= t("stats.total") %></th>
-        </tr>
-      </thead>
-
-      <tbody>
-        <% stats.participants_by_age.values.each do |group| %>
-          <tr>
-            <td><%= group[:range] %></td>
-            <td>
-              <strong>
-                <%= "#{group[:count]} (#{number_to_stats_percentage(group[:percentage])})" %>
-              </strong>
-              <div class="progress" tabindex="0">
-                <span class="progress-meter" style="width: <%= group[:percentage] %>%">
-                </span>
-              </div>
-            </td>
-          </tr>
-        <% end %>
-      </tbody>
-    </table>
-  </div>
-
-  <div id="participants_by_geozone" class="stats-group">
-    <h4><%= t("stats.by_geozone") %></h4>
-
-    <table>
-      <thead>
-        <tr>
-          <th><%= t("stats.geozone") %></th>
-          <th><%= t("stats.total") %></th>
-          <th><%= t("stats.geozone_participation") %></th>
-        </tr>
-      </thead>
-
-      <tbody>
-        <% stats.participants_by_geozone.each do |geozone, participants| %>
-          <tr>
-            <td><%= geozone %></td>
-            <td><%= "#{participants[:total][:count]} (#{number_to_stats_percentage(participants[:total][:percentage])})" %></td>
-            <td><%= number_to_stats_percentage(participants[:percentage]) %></td>
-          </tr>
-        <% end %>
-      </tbody>
-    </table>
-  </div>
 </div>

spec/models/statisticable_spec.rb

@@ -0,0 +1,148 @@
+require "rails_helper"
+
+describe Statisticable do
+  class DummyStats
+    include Statisticable
+
+    def participants
+      User.all
+    end
+  end
+
+  let(:stats) { DummyStats.new(nil) }
+
+  describe "#gender?" do
+    context "No participants" do
+      it "is false" do
+        expect(stats.gender?).to be false
+      end
+    end
+
+    context "All participants have no defined gender" do
+      before { create(:user, gender: nil) }
+
+      it "is false" do
+        expect(stats.gender?).to be false
+      end
+    end
+
+    context "There's a male participant" do
+      before { create(:user, gender: "male") }
+
+      it "is true" do
+        expect(stats.gender?).to be true
+      end
+    end
+
+    context "There's a female participant" do
+      before { create(:user, gender: "female") }
+
+      it "is true" do
+        expect(stats.gender?).to be true
+      end
+    end
+  end
+
+  describe "#age?" do
+    context "No participants" do
+      it "is false" do
+        expect(stats.age?).to be false
+      end
+    end
+
+    context "All participants have no defined age" do
+      before { create(:user, date_of_birth: nil) }
+
+      it "is false" do
+        expect(stats.age?).to be false
+      end
+    end
+
+    context "All participants have impossible ages" do
+      before do
+        create(:user, date_of_birth: 3.seconds.ago)
+        create(:user, date_of_birth: 3000.years.ago)
+      end
+
+      it "is false" do
+        expect(stats.age?).to be false
+      end
+    end
+
+    context "There's a participant with a defined age" do
+      before { create(:user, date_of_birth: 30.years.ago) }
+
+      it "is true" do
+        expect(stats.age?).to be true
+      end
+    end
+  end
+
+  describe "#geozone?" do
+    context "No participants" do
+      it "is false" do
+        expect(stats.geozone?).to be false
+      end
+    end
+
+    context "All participants have no defined geozone" do
+      before { create(:user, geozone: nil) }
+
+      it "is false" do
+        expect(stats.geozone?).to be false
+      end
+    end
+
+    context "There's a participant with a defined geozone" do
+      before { create(:user, geozone: create(:geozone)) }
+
+      it "is true" do
+        expect(stats.geozone?).to be true
+      end
+    end
+  end
+
+  describe "#stats_methods" do
+    it "includes total participants" do
+      expect(stats.stats_methods).to include(:total_participants)
+    end
+
+    context "no gender stats" do
+      before { allow(stats).to receive(:gender?).and_return(false) }
+
+      it "doesn't include gender methods" do
+        expect(stats.stats_methods).not_to include(:total_male_participants)
+      end
+    end
+
+    context "no age stats" do
+      before { allow(stats).to receive(:age?).and_return(false) }
+
+      it "doesn't include age methods" do
+        expect(stats.stats_methods).not_to include(:participants_by_age)
+      end
+    end
+
+    context "no geozone stats" do
+      before { allow(stats).to receive(:geozone?).and_return(false) }
+
+      it "doesn't include age methods" do
+        expect(stats.stats_methods).not_to include(:participants_by_geozone)
+      end
+    end
+
+    context "all gender, age and geozone stats" do
+      before do
+        allow(stats).to receive(:gender?).and_return(true)
+        allow(stats).to receive(:age?).and_return(true)
+        allow(stats).to receive(:geozone?).and_return(true)
+      end
+
+      it "includes all stats methods" do
+        expect(stats.stats_methods).to include(:total_male_participants)
+        expect(stats.stats_methods).to include(:participants_by_age)
+        expect(stats.stats_methods).to include(:participants_by_geozone)
+      end
+    end
+  end
+end