Merge pull request #161 from openHPI/feature/more-statistics

Feature/more statistics

Gemfile

@@ -40,7 +40,7 @@ gem 'tubesock'
 gem 'faye-websocket'
 gem 'eventmachine', '1.0.9.1' # explicitly added, this is used by faye-websocket, version 1.2.5 still has an error in eventmachine.rb:202: [BUG] Segmentation fault, which is not yet fixed and causes the whole ruby process to crash
 gem 'nokogiri'
-gem 'd3-rails'
+gem 'd3-rails', '~>4.0'
 gem 'rest-client'
 gem 'rubyzip'
 gem 'whenever', require: false

Gemfile.lock

@@ -388,7 +388,7 @@ DEPENDENCIES
   coffee-rails
   concurrent-ruby
   concurrent-ruby-ext
-  d3-rails
+  d3-rails (~> 4.0)
   database_cleaner
   docker-api
   eventmachine (= 1.0.9.1)

app/assets/javascripts/exercise_collections.js.erb

@@ -0,0 +1,102 @@
+$(function() {
+  if ($.isController('exercise_collections')) {
+    var data = $('#data').data('working-times');
+    var averageWorkingTimeValue = parseFloat($('#data').data('average-working-time'));
+
+    var margin = { top: 30, right: 40, bottom: 30, left: 50 },
+      width = 720 - margin.left - margin.right,
+      height = 500 - margin.top - margin.bottom;
+
+    var x = d3.scaleBand().range([0, width]);
+    var y = d3.scaleLinear().range([height, 0]);
+
+    var xAxis = d3.axisBottom(x);
+    var yAxisLeft = d3.axisLeft(y);
+
+    var tooltip = d3.select("#graph").append("div").attr("class", "exercise-id-tooltip");
+
+    var averageWorkingTime = d3.line()
+      .x(function (d) { return x(d.index) + x.bandwidth()/2; })
+      .y(function () { return y(averageWorkingTimeValue); });
+
+    var minWorkingTime = d3.line()
+      .x(function (d) { return x(d.index) + x.bandwidth()/2; })
+      .y(function () { return y(0.1*averageWorkingTimeValue); });
+
+    var maxWorkingTime = d3.line()
+      .x(function (d) { return x(d.index) + x.bandwidth()/2; })
+      .y(function () { return y(2*averageWorkingTimeValue); });
+
+    var svg = d3.select('#graph')
+      .append("svg")
+      .attr("width", width + margin.left + margin.right)
+      .attr("height", height + margin.top + margin.bottom)
+      .append("g")
+      .attr("transform",
+        "translate(" + margin.left + "," + margin.top + ")");
+
+    // Get the data
+    data = Object.keys(data).map(function (key, index) {
+      return {
+        index: index,
+        exercise_id: parseInt(key),
+        working_time: parseFloat(data[key])
+      };
+    });
+
+    // Scale the range of the data
+    x.domain(data.map(function (d) { return d.index; }));
+    y.domain([0, d3.max(data, function (d) { return d.working_time; })]);
+
+    // Add the X Axis
+    svg.append("g")
+      .attr("class", "x axis")
+      .attr("transform", "translate(0," + height + ")")
+      .call(xAxis);
+
+    // Add the Y Axis
+    svg.append("g")
+      .attr("class", "y axis")
+      .style("fill", "steelblue")
+      .call(yAxisLeft);
+
+    // Draw the bars
+    svg.selectAll("bar")
+      .data(data)
+      .enter()
+      .append("rect")
+      .attr("class", "value-bar")
+      .on("mousemove", function (d){
+        tooltip
+          .style("left", d3.event.pageX - 50 + "px")
+          .style("top", d3.event.pageY + 50 + "px")
+          .style("display", "inline-block")
+          .html("<%= I18n.t('activerecord.models.exercise.one') %> ID: " + d.exercise_id + "<br>" +
+            "<%= I18n.t('exercises.statistics.average_worktime') %>: " + d.working_time + "s");
+      })
+      .on("mouseout", function (){ tooltip.style("display", "none");})
+      .on("click", function (d) {
+        window.location.href = "/exercises/" + d.exercise_id + "/statistics";
+      })
+      .attr("x", function (d) { return x(d.index); })
+      .attr("width", x.bandwidth())
+      .attr("y", function (d) { return y(d.working_time); })
+      .attr("height", function (d) { return height - y(d.working_time); });
+
+    // Add the average working time path
+    svg.append("path")
+      .datum(data)
+      .attr("class", "line average-working-time")
+      .attr("d", averageWorkingTime);
+
+    // Add the anomaly paths (min/max average exercise working time)
+    svg.append("path")
+      .datum(data)
+      .attr("class", "line minimum-working-time")
+      .attr("d", minWorkingTime);
+    svg.append("path")
+      .datum(data)
+      .attr("class", "line maximum-working-time")
+      .attr("d", maxWorkingTime);
+  }
+});

app/assets/javascripts/exercise_graphs.js

@@ -1,9 +1,7 @@
 $(function() {
-    // http://localhost:3333/exercises/38/statistics good for testing
+    // /exercises/38/statistics good for testing
-    // originally at--> localhost:3333/exercises/69/statistics
 
     if ($.isController('exercises') && $('.graph-functions-2').isPresent()) {
-        // GET THE DATA
         var submissions = $('#data').data('submissions');
         var submissions_length = submissions.length;
 
@@ -14,10 +12,7 @@ $(function() {
         submissionsAutosaves = [];
         var maximumValue = 0;
 
-        var wtimes = $('#wtimes').data('working_times'); //.hidden#wtimes data-working_times=ActiveSupport::JSON.encode(working_times_until)
+        var wtimes = $('#wtimes').data('working_times');
-        
-        // console.log(submissions);
-        // console.log(wtimes);
 
         for (var i = 0;i<submissions_length;i++){
             var submission = submissions[i];
@@ -46,9 +41,6 @@ $(function() {
                 submissionsSaves.push(submissionArray[1]);
             }
         }
-        // console.log(submissionsScoreAndTimeAssess.length);
-        // console.log(submissionsScoreAndTimeSubmits);
-        // console.log(submissionsScoreAndTimeRuns);
 
         function get_minutes (time_stamp) {
             try {
@@ -94,33 +86,22 @@ $(function() {
                 height = (width * height_ratio) - margin.top - margin.bottom;
 
             // Set the ranges
-            var x = d3.scale.linear().range([0, width]);
+            var x = d3.scaleLinear().range([0, width]);
-            var y = d3.scale.linear().range([height,0]);
+            var y = d3.scaleLinear().range([height,0]);
 
-            //var x = d3.scale.linear()
+            //var x = d3.scaleLinear()
             //    .range([0, width]);
-            //var y = d3.scale.linear()
+            //var y = d3.scaleLinear()
             //    .range([0,height]); // - (height/20
 
-            var xAxis = d3.svg.axis()
+            var xAxis = d3.axisBottom(x).ticks(20);
-                .scale(x)
+            var yAxis = d3.axisLeft()
-                .orient("bottom")
+                .scale(d3.scaleLinear().domain([0,maximumValue]).range([height,0]))
-                .ticks(20);
-
-
-            var yAxis = d3.svg.axis()
-                .scale(d3.scale.linear().domain([0,maximumValue]).range([height,0]))//y
-                // .scale(y)
-                .orient("left")
                 .ticks(maximumValue)
-                .innerTickSize(-width)
+                .tickSizeInner(-width)
-                .outerTickSize(0);
+                .tickSizeOuter(0);
 
-            //var line = d3.svg.line()
+            var line = d3.line()
-            //    .x(function(d) { return x(d.date); })
-            //    .y(function(d) { return y(d.close); });
-
-            var line = d3.svg.line()
                 .x(function (d) {
                     // console.log(d[1]);
                     return x(d[1]);
@@ -288,23 +269,12 @@ $(function() {
                         .text(color_hash[String(i)][0]);
 
                 });
-
-
-
-            // function type(d) {
-            //     d.frequency = +d.frequency;
-            //     return d;
-            // }
-
-            //.on("mousemove", mMove)//new again
-            //.append("title");
-
         }
 
         try{
             graph_assesses();
         } catch(err){
-            alert("could not draw the graph");
+            console.error("Could not draw the graph", err);
         }
 
   }

app/assets/javascripts/working_time_graphs.js

@@ -38,18 +38,6 @@ $(function() {
           }
       }
 
-      // minutes_count[(maximum_minutes + 1)] = 0;
-      //$('.graph-functions').html("<p></p>")
-
-      // var minutes_count = new Array(10);
-      // var minutes_array_len = minutes_array.length;
-      // for (var i=0; i< minutes_count; i++){
-      //
-      //     for (var j = 0; j < minutes_array_len; j++){
-      //         if ()
-      //     }
-      // }
-
       function getWidth() {
           if (self.innerHeight) {
               return self.innerWidth;
@@ -81,22 +69,17 @@ $(function() {
 
           //var formatDate = d3.time.format("%M");
 
-          var x = d3.scale.linear()
+          var x = d3.scaleLinear()
               .range([0, width]);
-          var y = d3.scale.linear()
+          var y = d3.scaleLinear()
               .range([height, 0]); // - (height/20
-          var xAxis = d3.svg.axis()
+          var xAxis = d3.axisBottom(x).ticks(20);
-              .scale(x)
+          var yAxis = d3.axisLeft(y)
-              .orient("bottom")
-              .ticks(20);
-          var yAxis = d3.svg.axis()
-              .scale(y)
-              .orient("left")
               .ticks(20)
-              .innerTickSize(-width)
+              .tickSizeInner(-width)
-              .outerTickSize(0);
+              .tickSizeOuter(0);
 
-          var line = d3.svg.line()
+          var line = d3.line()
               .x(function (d, i) {
                   return x(i);
               })
@@ -225,7 +208,7 @@ $(function() {
           var x = d3.scale.ordinal()
               .rangeRoundBands([0, width], .1);
 
-          var y = d3.scale.linear()
+          var y = d3.scaleLinear()
               .range([0,height-(margin.top + margin.bottom)]);
 
 
@@ -236,7 +219,7 @@ $(function() {
 
 
           var yAxis = d3.svg.axis()
-              .scale(d3.scale.linear().domain([0,max_of_array]).range([height,0]))//y
+              .scale(d3.scaleLinear().domain([0,max_of_array]).range([height,0]))//y
               .orient("left")
               .ticks(10)
               .innerTickSize(-width);
@@ -299,7 +282,7 @@ $(function() {
               .text("Working Time (Minutes)")
               .style('font-size', 14);
 
-          y = d3.scale.linear()
+          y = d3.scaleLinear()
               .domain([(0),max_of_array])
               .range([0,height]);
 

app/assets/stylesheets/exercise_collections.scss

@@ -0,0 +1,69 @@
+$time-color: #008cba;
+$min-color: #8efa00;
+$avg-color: #ffca00;
+$max-color: #ff2600;
+
+path.line.minimum-working-time {
+  stroke: $min-color;
+}
+
+path.line.average-working-time {
+  stroke: $avg-color;
+}
+
+path.line.maximum-working-time {
+  stroke: $max-color;
+}
+
+rect.value-bar {
+  fill: $time-color;
+  cursor: pointer;
+}
+
+#legend {
+  display: flex;
+  margin-top: 20px;
+
+  .legend-entry {
+    flex-grow: 1;
+    display: flex;
+
+    .box {
+      width: 20px;
+      height: 20px;
+      border: solid 1px #000;
+    }
+
+    .box.time {
+      background-color: $time-color;
+    }
+
+    .box.min {
+      background-color: $min-color;
+    }
+
+    .box.avg {
+      background-color: $avg-color;
+    }
+
+    .box.max {
+      background-color: $max-color;
+    }
+
+    .box-label {
+      margin-left: 5px;
+      margin-right: 15px;
+    }
+  }
+}
+
+.exercise-id-tooltip {
+  position: absolute;
+  display: none;
+  min-width: 80px;
+  height: auto;
+  background: none repeat scroll 0 0 #ffffff;
+  border: 1px solid #008cba;
+  padding: 14px;
+  text-align: center;
+}

app/assets/stylesheets/statistics.css.scss

@@ -58,3 +58,46 @@ div.negative-result {
   box-shadow: 0px 0px 11px 1px rgba(222,0,0,1);
 }
 
+/////////////////////////////////////////////////////////////////////////////////////////////
+// StatisticsController:
+
+#statistics-container {
+  margin-bottom: 40px;
+}
+
+.statistics-wrapper {
+  display: grid;
+  grid-template-columns: repeat(4, 1fr);
+  grid-auto-rows: 150px;
+  grid-gap: 10px;
+
+  > a {
+    color: #fff;
+    text-decoration: none;
+
+    > div {
+      border: 2px solid #0055ba;
+      border-radius: 5px;
+      background-color: #008cba;
+      padding: 1em;
+      display: flex;
+      flex-flow: column-reverse;
+      text-align: center;
+
+      > .data {
+        flex-grow: 1;
+        font-size: 40px;
+        vertical-align: middle;
+        line-height: 50px;
+
+        > .unit {
+          font-size: 20px;
+        }
+      }
+
+      > .title {
+        height: 42px;
+      }
+    }
+  }
+}

app/controllers/exercise_collections_controller.rb

@@ -1,7 +1,7 @@
 class ExerciseCollectionsController < ApplicationController
   include CommonBehavior
 
-  before_action :set_exercise_collection, only: [:show, :edit, :update, :destroy]
+  before_action :set_exercise_collection, only: [:show, :edit, :update, :destroy, :statistics]
 
   def index
     @exercise_collections = ExerciseCollection.all.paginate(:page => params[:page])
@@ -35,6 +35,9 @@ class ExerciseCollectionsController < ApplicationController
     update_and_respond(object: @exercise_collection, params: exercise_collection_params)
   end
 
+  def statistics
+  end
+
   private
 
   def set_exercise_collection

app/controllers/statistics_controller.rb

@@ -0,0 +1,16 @@
+class StatisticsController < ApplicationController
+  include StatisticsHelper
+
+  def policy_class
+    StatisticsPolicy
+  end
+
+  def show
+    authorize self
+    respond_to do |format|
+      format.html
+      format.json { render(json: statistics_data) }
+    end
+  end
+
+end

app/helpers/statistics_helper.rb

@@ -0,0 +1,125 @@
+module StatisticsHelper
+
+  def statistics_data
+    [
+        {
+            key: 'users',
+            name: t('statistics.sections.users'),
+            entries: user_statistics
+        },
+        {
+            key: 'exercises',
+            name: t('statistics.sections.exercises'),
+            entries: exercise_statistics
+        },
+        {
+            key: 'request_for_comments',
+            name: t('statistics.sections.request_for_comments'),
+            entries: rfc_statistics
+        }
+    ]
+  end
+
+  def user_statistics
+    [
+        {
+            key: 'internal_users',
+            name: t('activerecord.models.internal_user.other'),
+            data: InternalUser.count,
+            url: internal_users_path
+        },
+        {
+            key: 'external_users',
+            name: t('activerecord.models.external_user.other'),
+            data: ExternalUser.count,
+            url: external_users_path
+        },
+        {
+            key: 'currently_active',
+            name: t('statistics.entries.users.currently_active'),
+            data: ExternalUser.joins(:submissions)
+                      .where(['submissions.created_at >= ?', DateTime.now - 5.minutes])
+                      .distinct('external_users.id').count
+        }
+    ]
+  end
+
+  def exercise_statistics
+    [
+        {
+            key: 'exercises',
+            name: t('activerecord.models.exercise.other'),
+            data: Exercise.count,
+            url: exercises_path
+        },
+        {
+            key: 'average_submissions',
+            name: t('statistics.entries.exercises.average_number_of_submissions'),
+            data: (Submission.count.to_f / Exercise.count).round(2)
+        },
+        {
+            key: 'submissions_per_minute',
+            name: t('statistics.entries.exercises.submissions_per_minute'),
+            data: (Submission.where('created_at >= ?', DateTime.now - 1.hours).count.to_f / 60).round(2),
+            unit: '/min'
+        },
+        {
+            key: 'execution_environments',
+            name: t('activerecord.models.execution_environment.other'),
+            data: ExecutionEnvironment.count,
+            url: execution_environments_path
+        },
+        {
+            key: 'exercise_collections',
+            name: t('activerecord.models.exercise_collection.other'),
+            data: ExerciseCollection.count,
+            url: exercise_collections_path
+        }
+    ]
+  end
+
+  def rfc_statistics
+    [
+        {
+            key: 'rfcs',
+            name: t('activerecord.models.request_for_comment.other'),
+            data: RequestForComment.count,
+            url: request_for_comments_path
+        },
+        {
+            key: 'percent_solved',
+            name: t('statistics.entries.request_for_comments.percent_solved'),
+            data: (100.0 / RequestForComment.count * RequestForComment.where(solved: true).count).round(1),
+            unit: '%',
+            url: request_for_comments_path + '?q%5Bsolved_not_eq%5D=0'
+        },
+        {
+            key: 'percent_soft_solved',
+            name: t('statistics.entries.request_for_comments.percent_soft_solved'),
+            data: (100.0 / RequestForComment.count * RequestForComment.unsolved.where(full_score_reached: true).count).round(1),
+            unit: '%',
+            url: request_for_comments_path
+        },
+        {
+            key: 'percent_unsolved',
+            name: t('statistics.entries.request_for_comments.percent_unsolved'),
+            data: (100.0 / RequestForComment.count * RequestForComment.unsolved.count).round(1),
+            unit: '%',
+            url: request_for_comments_path + '?q%5Bsolved_not_eq%5D=1'
+        },
+        {
+            key: 'comments',
+            name: t('activerecord.models.comment.other'),
+            data: Comment.count
+        },
+        {
+            key: 'rfcs_with_comments',
+            name: t('statistics.entries.request_for_comments.with_comments'),
+            data: RequestForComment.joins('join "submissions" s on s.id = request_for_comments.submission_id
+                join "files" f on f.context_id = s.id and f.context_type = \'Submission\'
+                join "comments" c on c.file_id = f.id').group('request_for_comments.id').count.size
+        }
+    ]
+  end
+
+end

app/helpers/time_helper.rb

@@ -0,0 +1,12 @@
+module TimeHelper
+
+  # convert timestamps ('12:34:56.789') to seconds
+  def time_to_f(timestamp)
+    unless timestamp.nil?
+      timestamp = timestamp.split(':')
+      return timestamp[0].to_i * 60 * 60 + timestamp[1].to_i * 60 + timestamp[2].to_f
+    end
+    nil
+  end
+
+end

app/models/exercise_collection.rb

@@ -1,8 +1,21 @@
 class ExerciseCollection < ActiveRecord::Base
+  include TimeHelper
 
   has_and_belongs_to_many :exercises
   belongs_to :user, polymorphic: true
 
+  def exercise_working_times
+    working_times = {}
+    exercises.each do |exercise|
+      working_times[exercise.id] = time_to_f exercise.average_working_time
+    end
+    working_times
+  end
+
+  def average_working_time
+    exercise_working_times.values.reduce(:+) / exercises.size
+  end
+
   def to_s
     "#{I18n.t('activerecord.models.exercise_collection.one')}: #{name} (#{id})"
   end

app/policies/exercise_collection_policy.rb

@@ -1,3 +1,7 @@
 class ExerciseCollectionPolicy < AdminOnlyPolicy
 
+  def statistics?
+    admin?
+  end
+
 end

app/policies/statistics_policy.rb

@@ -0,0 +1,2 @@
+class StatisticsPolicy < AdminOnlyPolicy
+end

app/views/application/_navigation.html.slim

@@ -7,6 +7,7 @@
       ul.dropdown-menu role='menu'
         - if current_user.admin?
           li = link_to(t('breadcrumbs.dashboard.show'), admin_dashboard_path)
+          li = link_to(t('breadcrumbs.statistics.show'), statistics_path)
           li.divider
         - models = [ExecutionEnvironment, Exercise, ExerciseCollection, ProxyExercise, Tag, Consumer, CodeHarborLink, UserExerciseFeedback,
                 ErrorTemplate, ErrorTemplateAttribute, ExternalUser, FileType, FileTemplate, InternalUser].sort_by {|model| model.model_name.human(count: 2) }

app/views/exercise_collections/index.html.slim

@@ -8,7 +8,7 @@ h1 = ExerciseCollection.model_name.human(count: 2)
         th = t('activerecord.attributes.exercise_collections.name')
         th = t('activerecord.attributes.exercise_collections.updated_at')
         th = t('activerecord.attributes.exercise_collections.exercises')
-        th colspan=3 = t('shared.actions')
+        th colspan=4 = t('shared.actions')
     tbody
       - @exercise_collections.each do |collection|
         tr
@@ -18,6 +18,7 @@ h1 = ExerciseCollection.model_name.human(count: 2)
           td = collection.exercises.size
           td = link_to(t('shared.show'), collection)
           td = link_to(t('shared.edit'), edit_exercise_collection_path(collection))
+          td = link_to(t('shared.statistics'), statistics_exercise_collection_path(collection))
           td = link_to(t('shared.destroy'), collection, data: {confirm: t('shared.confirm_destroy')}, method: :delete)
 
 = render('shared/pagination', collection: @exercise_collections)

app/views/exercise_collections/statistics.html.slim

@@ -0,0 +1,17 @@
+h1 = @exercise_collection
+
+= row(label: 'exercise_collections.name', value: @exercise_collection.name)
+= row(label: 'exercise_collections.updated_at', value: @exercise_collection.updated_at)
+= row(label: 'exercise_collections.exercises', value: @exercise_collection.exercises.count)
+= row(label: 'exercises.statistics.average_worktime', value: @exercise_collection.average_working_time.round(3).to_s + 's')
+
+#graph
+  #data.hidden(data-working-times=ActiveSupport::JSON.encode(@exercise_collection.exercise_working_times) data-average-working-time=@exercise_collection.average_working_time)
+  #legend
+    - {time: t('exercises.statistics.average_worktime'),
+        min: 'min. anomaly threshold',
+        avg: 'average time',
+        max: 'max. anomaly threshold'}.each_pair do |klass, label|
+      .legend-entry
+        div(class="box #{klass}")
+        .box-label = label

app/views/statistics/show.html.slim

@@ -0,0 +1,12 @@
+
+#statistics-container
+  - statistics_data.each do | section |
+    h2 = section[:name]
+    .statistics-wrapper data-key=section[:key]
+      - section[:entries].each do | entry |
+        a href=entry[:url]
+          div data-key=entry[:key]
+            .title = entry[:name]
+            .data
+              span = entry[:data].to_s
+              span.unit = entry[:unit] if entry.key? :unit

config/locales/de.yml

@@ -219,6 +219,8 @@ de:
       show: Dashboard
     sessions:
       destroy_through_lti: Code-Abgabe
+    statistics:
+      show: "Statistiken"
   consumers:
     show:
       link: Konsument
@@ -734,3 +736,19 @@ de:
   subscriptions:
     successfully_unsubscribed: "Ihr Abonnement für weitere Kommentare auf dieser Kommentaranfrage wurde erfolgreich beendet."
     subscription_not_existent: "Das Abonnement, von dem Sie sich abmelden wollen, existiert nicht."
+  statistics:
+    sections:
+      users: "Benutzer"
+      exercises: "Aufgaben"
+      request_for_comments: "Kommentaranfragen"
+    entries:
+      exercises:
+        average_number_of_submissions: "Durchschnittliche Zahl von Abgaben"
+        submissions_per_minute: "Aktuelle Abgabenhäufigkeit (1h)"
+      request_for_comments:
+        percent_solved: "Beantwortete Anfragen"
+        percent_unsolved: "Unbeantwortete Anfragen"
+        percent_soft_solved: "Ungelöst mit voller Punktzahl"
+        with_comments: "Anfragen mit Kommentaren"
+      users:
+        currently_active: "Aktiv (5 Minuten)"

config/locales/en.yml

@@ -219,6 +219,8 @@ en:
       show: Dashboard
     sessions:
       destroy_through_lti: Code Submission
+    statistics:
+      show: "Statistics"
   consumers:
     show:
       link: Consumer
@@ -734,3 +736,19 @@ en:
   subscriptions:
     successfully_unsubscribed: "You successfully unsubscribed from this Request for Comment"
     subscription_not_existent: "The subscription you want to unsubscribe from does not exist."
+  statistics:
+    sections:
+      users: "Users"
+      exercises: "Exercises"
+      request_for_comments: "Requests for Comment"
+    entries:
+      exercises:
+        average_number_of_submissions: "Average Number of Submissions"
+        submissions_per_minute: "Current Submission Volume (1h)"
+      request_for_comments:
+        percent_solved: "Solved Requests"
+        percent_unsolved: "Unsolved Requests"
+        percent_soft_solved: "Unsolved with full score"
+        with_comments: "RfCs with Comments"
+      users:
+        currently_active: "Active (5 minutes)"

config/routes.rb

@@ -42,6 +42,8 @@ Rails.application.routes.draw do
 
   get '/help', to: 'application#help'
 
+  get 'statistics/', to: 'statistics#show'
+
   concern :statistics do
     member do
       get :statistics
@@ -82,7 +84,11 @@ Rails.application.routes.draw do
     end
   end
 
-  resources :exercise_collections
+  resources :exercise_collections do
+    member do
+      get :statistics
+    end
+  end
 
   resources :proxy_exercises do
     member do

lib/tasks/detect_exercise_anomalies.rake

@@ -22,6 +22,8 @@ namespace :detect_exercise_anomalies do
   AVERAGE_WORKING_TIME_CACHE = {}
 
   task :with_at_least, [:number_of_exercises, :number_of_solutions] => :environment do |task, args|
+    include TimeHelper
+
     number_of_exercises = args[:number_of_exercises]
     number_of_solutions = args[:number_of_solutions]
 
@@ -71,14 +73,6 @@ namespace :detect_exercise_anomalies do
     end
   end
 
-  def time_to_f(timestamp)
-    unless timestamp.nil?
-      timestamp = timestamp.split(':')
-      return timestamp[0].to_i * 60 * 60 + timestamp[1].to_i * 60 + timestamp[2].to_f
-    end
-    nil
-  end
-
   def get_average_working_time(exercise)
     unless AVERAGE_WORKING_TIME_CACHE.key?(exercise.id)
       seconds = time_to_f exercise.average_working_time