Use cursored pagination, remove WillPaginate

Gemfile

@@ -22,8 +22,6 @@ gem 'haml', '~> 5.0'
 gem 'bootstrap-sass', '~> 3.4.0'
 gem 'bootswatch-rails'
 gem 'sweetalert-rails'
-gem 'will_paginate'
-gem 'will_paginate-bootstrap'
 gem 'devise', '~> 4.0'
 gem 'devise-i18n'
 gem 'devise-async'

Gemfile.lock

@@ -499,9 +499,6 @@ GEM
     websocket-driver (0.7.1)
       websocket-extensions (>= 0.1.0)
     websocket-extensions (0.1.4)
-    will_paginate (3.3.0)
-    will_paginate-bootstrap (1.0.2)
-      will_paginate (>= 3.0.3)
     xpath (3.2.0)
       nokogiri (~> 1.8)
 
@@ -584,8 +581,6 @@ DEPENDENCIES
   uglifier (>= 1.3.0)
   unicorn
   web-console (< 4.0.0)
-  will_paginate
-  will_paginate-bootstrap
 
 BUNDLED WITH
    2.1.4

app/controllers/group_controller.rb

@@ -3,6 +3,13 @@ class GroupController < ApplicationController
 
   def index
     @group = current_user.groups.find_by_name!(params[:group_name])
-    @timeline = @group.timeline.paginate(page: params[:page])
+    @timeline = @group.cursored_timeline(last_id: params[:last_id])
+    @timeline_last_id = @timeline.map(&:id).min
+    @more_data_available = !@group.cursored_timeline(last_id: @timeline_last_id, size: 1).count.zero?
+
+    respond_to do |format|
+      format.html
+      format.js
+    end
   end
 end

app/controllers/inbox_controller.rb

@@ -2,28 +2,37 @@ class InboxController < ApplicationController
   before_action :authenticate_user!
 
   def show
-    @inbox = Inbox.where(user: current_user)
-                  .order(:created_at).reverse_order
-                  .paginate(page: params[:page])
-    @inbox_count = Inbox.where(user: current_user).count
+    @inbox = current_user.cursored_inbox(last_id: params[:last_id])
+    @inbox_last_id = @inbox.map(&:id).min
+    @more_data_available = !current_user.cursored_inbox(last_id: @inbox_last_id, size: 1).count.zero?
+    @inbox_count = current_user.inboxes.count
+
     if params[:author].present?
       begin
         @author = true
         @target_user = User.where('LOWER(screen_name) = ?', params[:author].downcase).first!
-        @inbox_author = current_user.inboxes.joins(:question)
-                                            .where(questions: { user_id: @target_user.id, author_is_anonymous: false })
-                                            .paginate(page: params[:page])
-        @inbox_author_count = current_user.inboxes.joins(:question)
-                                                  .where(questions: { user_id: @target_user.id, author_is_anonymous: false })
-                                                  .count
+        @inbox_author = @inbox.joins(:question)
+                              .where(questions: { user_id: @target_user.id, author_is_anonymous: false })
+        @inbox_author_count = current_user.inboxes
+                                          .joins(:question)
+                                          .where(questions: { user_id: @target_user.id, author_is_anonymous: false })
+                                          .count
+
         if @inbox_author.empty?
           @empty = true
           flash.now[:info] = "No questions from @#{params[:author]} found, showing default entries instead!"
         else
           @inbox = @inbox_author
           @inbox_count = @inbox_author_count
+          @inbox_last_id = @inbox.map(&:id).min
+          @more_data_available = !current_user.cursored_inbox(last_id: @inbox_last_id, size: 1)
+                                              .joins(:question)
+                                              .where(questions: { user_id: @target_user.id, author_is_anonymous: false })
+                                              .count
+                                              .zero?
         end
-      rescue
+      rescue => e
+        NewRelic::Agent.notice_error(e)
         flash.now[:error] = "No user with the name @#{params[:author]} found, showing default entries instead!"
         @not_found = true
       end

app/controllers/notifications_controller.rb

@@ -3,16 +3,28 @@ class NotificationsController < ApplicationController
 
   def index
     @type = params[:type]
-    @notifications = if @type == 'all'
-                       Notification.for(current_user)
-                     elsif @type == 'new'
-                       Notification.for(current_user).where(new: true)
-                     else
-                       Notification.for(current_user).where('LOWER(target_type) = ?', @type)
-                     end.paginate(page: params[:page])
+    @notifications = cursored_notifications_for(type: @type, last_id: params[:last_id])
+    @notifications_last_id = @notifications.map(&:id).min
+    @more_data_available = !cursored_notifications_for(type: @type, last_id: @notifications_last_id, size: 1).count.zero?
+
     respond_to do |format|
       format.html
       format.js
     end
   end
+
+  private
+
+  def cursored_notifications_for(type:, last_id:, size: nil)
+    cursor_params = { last_id: last_id, size: size }.compact
+
+    case type
+    when 'all'
+      Notification.cursored_for(current_user, **cursor_params)
+    when 'new'
+      Notification.cursored_for(current_user, new: true, **cursor_params)
+    else
+      Notification.cursored_for_type(current_user, type, **cursor_params)
+    end
+  end
 end

app/controllers/public_controller.rb

@@ -2,7 +2,10 @@ class PublicController < ApplicationController
   before_action :authenticate_user!
 
   def index
-    @timeline = Answer.joins(:user).where(users: { privacy_allow_public_timeline: true }).all.reverse_order.paginate(page: params[:page])
+    @timeline = Answer.cursored_public_timeline(last_id: params[:last_id])
+    @timeline_last_id = @timeline.map(&:id).min
+    @more_data_available = !Answer.cursored_public_timeline(last_id: @timeline_last_id, size: 1).count.zero?
+
     respond_to do |format|
       format.html
       format.js

app/controllers/question_controller.rb

@@ -1,7 +1,10 @@
 class QuestionController < ApplicationController
   def show
     @question = Question.find(params[:id])
-    @answers = @question.answers.reverse_order.paginate(page: params[:page])
+    @answers = @question.cursored_answers(last_id: params[:last_id])
+    @answers_last_id = @answers.map(&:id).min
+    @more_data_available = !@question.cursored_answers(last_id: @answers_last_id, size: 1).count.zero?
+
     respond_to do |format|
       format.html
       format.js

app/controllers/static_controller.rb

@@ -1,7 +1,12 @@
+# frozen_string_literal: true
+
 class StaticController < ApplicationController
   def index
     if user_signed_in?
-      @timeline = current_user.timeline.paginate(page: params[:page])
+      @timeline = current_user.cursored_timeline(last_id: params[:last_id])
+      @timeline_last_id = @timeline.map(&:id).min
+      @more_data_available = !current_user.cursored_timeline(last_id: @timeline_last_id, size: 1).count.zero?
+
       respond_to do |format|
         format.html
         format.js

app/controllers/user_controller.rb

@@ -5,7 +5,9 @@ class UserController < ApplicationController
 
   def show
     @user = User.where('LOWER(screen_name) = ?', params[:username].downcase).first!
-    @answers = @user.answers.reverse_order.paginate(page: params[:page])
+    @answers = @user.cursored_answers(last_id: params[:last_id])
+    @answers_last_id = @answers.map(&:id).min
+    @more_data_available = !@user.cursored_answers(last_id: @answers_last_id, size: 1).count.zero?
 
     if user_signed_in?
       notif = Notification.where(target_type: "Relationship", target_id: @user.active_relationships.where(target_id: current_user.id).pluck(:id), recipient_id: current_user.id, new: true).first
@@ -72,7 +74,9 @@ class UserController < ApplicationController
   def followers
     @title = 'Followers'
     @user = User.where('LOWER(screen_name) = ?', params[:username].downcase).first!
-    @users = @user.followers.reverse_order.paginate(page: params[:page])
+    @users = @user.cursored_followers(last_id: params[:last_id])
+    @users_last_id = @users.map(&:id).min
+    @more_data_available = !@user.cursored_followers(last_id: @users_last_id, size: 1).count.zero?
     @type = :friend
     render 'show_follow'
   end
@@ -80,7 +84,9 @@ class UserController < ApplicationController
   def friends
     @title = 'Following'
     @user = User.where('LOWER(screen_name) = ?', params[:username].downcase).first!
-    @users = @user.friends.reverse_order.paginate(page: params[:page])
+    @users = @user.cursored_friends(last_id: params[:last_id])
+    @users_last_id = @users.map(&:id).min
+    @more_data_available = !@user.cursored_friends(last_id: @users_last_id, size: 1).count.zero?
     @type = :friend
     render 'show_follow'
   end
@@ -88,7 +94,9 @@ class UserController < ApplicationController
   def questions
     @title = 'Questions'
     @user = User.where('LOWER(screen_name) = ?', params[:username].downcase).first!
-    @questions = @user.questions.where(author_is_anonymous: false).reverse_order.paginate(page: params[:page])
+    @questions = @user.cursored_questions(last_id: params[:last_id])
+    @questions_last_id = @questions.map(&:id).min
+    @more_data_available = !@user.cursored_questions(last_id: @questions_last_id, size: 1).count.zero?
   end
 
   def data

app/models/answer.rb

@@ -1,4 +1,6 @@
 class Answer < ApplicationRecord
+  extend Answer::TimelineMethods
+
   belongs_to :user
   belongs_to :question
   has_many :comments, dependent: :destroy

app/models/answer/timeline_methods.rb

@@ -0,0 +1,14 @@
+# frozen_string_literal: true
+
+module Answer::TimelineMethods
+  include CursorPaginatable
+
+  define_cursor_paginator :cursored_public_timeline, :public_timeline
+
+  def public_timeline
+    joins(:user)
+      .where(users: { privacy_allow_public_timeline: true })
+      .order(:created_at)
+      .reverse_order
+  end
+end

app/models/concerns/cursor_paginatable.rb

@@ -0,0 +1,38 @@
+# frozen_string_literal: true
+
+module CursorPaginatable
+  extend ActiveSupport::Concern
+
+  module ClassMethods
+    # Defines a cursor paginator.
+    #
+    # This method will define a new method +name+, which accepts the keyword
+    # arguments +last_id+ for defining the last id the cursor will operate on,
+    # and +size+ for the amount of records it should return.
+    #
+    # @param name [Symbol] The name of the method for the cursor paginator
+    # @param scope [Symbol] The name of the method which returns an
+    #   ActiveRecord scope.
+    #
+    # @example
+    # class User
+    #   has_many :answers
+    #
+    #   include CursorPaginatable
+    #   define_cursor_paginator :cursored_answers, :recent_answers
+    #
+    #   def recent_answers
+    #     self.answers.order(:created_at).reverse_order
+    #   end
+    # end
+    def define_cursor_paginator(name, scope, default_size: APP_CONFIG.fetch('items_per_page'))
+      class_eval <<-RUBY, __FILE__, __LINE__ + 1
+        def #{name}(*args, last_id: nil, size: #{default_size}, **kwargs)
+          s = self.#{scope}(*args, **kwargs).limit(size)
+          s = s.where(s.arel_table[:id].lt(last_id)) if last_id.present?
+          s
+        end
+      RUBY
+    end
+  end
+end

app/models/group.rb

@@ -1,6 +1,8 @@
 # frozen_string_literal: true
 
 class Group < ApplicationRecord
+  include Group::TimelineMethods
+
   belongs_to :user
   has_many :group_members, dependent: :destroy
 
@@ -22,9 +24,4 @@ class Group < ApplicationRecord
   def remove_member(user)
     GroupMember.where(group: self, user: user).first!.destroy
   end
-
-  # @return [Array] the groups' timeline
-  def timeline
-    Answer.where("user_id in (?)", members.pluck(:user_id)).order(:created_at).reverse_order
-  end
 end

app/models/group/timeline_methods.rb

@@ -0,0 +1,12 @@
+# frozen_string_literal: true
+
+module Group::TimelineMethods
+  include CursorPaginatable
+
+  define_cursor_paginator :cursored_timeline, :timeline
+
+  # @return [Array] the groups' timeline
+  def timeline
+    Answer.where('user_id in (?)', members.pluck(:user_id)).order(:created_at).reverse_order
+  end
+end

app/models/notification.rb

@@ -3,10 +3,19 @@ class Notification < ApplicationRecord
   belongs_to :target, polymorphic: true
 
   class << self
+    include CursorPaginatable
+
+    define_cursor_paginator :cursored_for, :for
+    define_cursor_paginator :cursored_for_type, :for_type
+
     def for(recipient, options={})
       self.where(options.merge!(recipient: recipient)).order(:created_at).reverse_order
     end
 
+    def for_type(recipient, type, options={})
+      self.where(options.merge!(recipient: recipient)).where('LOWER(target_type) = ?', type).order(:created_at).reverse_order
+    end
+
     def notify(recipient, target)
       return nil unless target.respond_to? :notification_type
 

app/models/question.rb

@@ -1,4 +1,6 @@
 class Question < ApplicationRecord
+  include Question::AnswerMethods
+
   belongs_to :user
   has_many :answers, dependent: :destroy
   has_many :inboxes, dependent: :destroy

app/models/question/answer_methods.rb

@@ -0,0 +1,13 @@
+# frozen_string_literal: true
+
+module Question::AnswerMethods
+  include CursorPaginatable
+
+  define_cursor_paginator :cursored_answers, :ordered_answers
+
+  def ordered_answers
+    answers
+      .order(:created_at)
+      .reverse_order
+  end
+end

app/models/user.rb

@@ -1,4 +1,10 @@
 class User < ApplicationRecord
+  include User::AnswerMethods
+  include User::InboxMethods
+  include User::QuestionMethods
+  include User::RelationshipMethods
+  include User::TimelineMethods
+
   # Include default devise modules. Others available are:
   # :confirmable, :lockable, :timeoutable and :omniauthable
   devise :database_authenticatable, :async, :registerable,
@@ -100,11 +106,6 @@ class User < ApplicationRecord
     end
   end
 
-  # @return [Array] the users' timeline
-  def timeline
-    Answer.where("user_id in (?) OR user_id = ?", friend_ids, id).order(:created_at).reverse_order
-  end
-
   # follows an user.
   def follow(target_user)
     active_relationships.create(target: target_user)

app/models/user/answer_methods.rb

@@ -0,0 +1,13 @@
+# frozen_string_literal: true
+
+module User::AnswerMethods
+  include CursorPaginatable
+
+  define_cursor_paginator :cursored_answers, :ordered_answers
+
+  def ordered_answers
+    answers
+      .order(:created_at)
+      .reverse_order
+  end
+end

app/models/user/inbox_methods.rb

@@ -0,0 +1,14 @@
+# frozen_string_literal: true
+
+module User::InboxMethods
+  include CursorPaginatable
+
+  define_cursor_paginator :cursored_inbox, :ordered_inbox
+
+  def ordered_inbox
+    inboxes
+      .includes(:question, :user)
+      .order(:created_at)
+      .reverse_order
+  end
+end

app/models/user/question_methods.rb

@@ -0,0 +1,13 @@
+# frozen_string_literal: true
+
+module User::QuestionMethods
+  include CursorPaginatable
+
+  define_cursor_paginator :cursored_questions, :ordered_questions
+
+  def ordered_questions
+    questions
+      .order(:created_at)
+      .reverse_order
+  end
+end

app/models/user/relationship_methods.rb

@@ -0,0 +1,16 @@
+# frozen_string_literal: true
+
+module User::RelationshipMethods
+  include CursorPaginatable
+
+  define_cursor_paginator :cursored_friends, :ordered_friends
+  define_cursor_paginator :cursored_followers, :ordered_followers
+
+  def ordered_friends
+    friends.reverse_order
+  end
+
+  def ordered_followers
+    followers.reverse_order
+  end
+end

app/models/user/timeline_methods.rb

@@ -0,0 +1,12 @@
+# frozen_string_literal: true
+
+module User::TimelineMethods
+  include CursorPaginatable
+
+  define_cursor_paginator :cursored_timeline, :timeline
+
+  # @return [Array] the users' timeline
+  def timeline
+    Answer.where('user_id in (?) OR user_id = ?', friend_ids, id).order(:created_at).reverse_order
+  end
+end

app/views/group/index.html.haml

@@ -10,9 +10,9 @@
       - @timeline.each do |answer|
         = render 'shared/answerbox', a: answer
 
-    #pagination= will_paginate @timeline, renderer: BootstrapPagination::Rails, page_links: false
+    = render 'shared/cursored_pagination_dummy', more_data_available: @more_data_available, last_id: @timeline_last_id
 
-    - if @timeline.next_page
-      %button#load-more-btn.btn.btn-default{type: :button, data: { current_page: @timeline.current_page }}
+    - if @more_data_available
+      %button#load-more-btn.btn.btn-default{type: :button, data: { last_id: @timeline_last_id }}
         = t 'views.actions.load'
 .visible-xs= render 'shared/links'

app/views/group/index.js.erb

@@ -1,8 +1,8 @@
 $('#timeline').append('<% @timeline.each do |answer|
   %><%= j render 'shared/answerbox', a: answer
 %><% end %>');
-<% if @timeline.next_page %>
-  $('#pagination').html('<%= j will_paginate @timeline, renderer: BootstrapPagination::Rails, page_links: false %>');
+<% if @more_data_available %>
+  $('#pagination').html('<%= j render 'shared/cursored_pagination_dummy', more_data_available: @more_data_available, last_id: @timeline_last_id %>');
 <% else %>
   $('#pagination, #load-more-btn').remove();
-<% end %>
+<% end %>

app/views/inbox/show.html.haml

@@ -12,10 +12,10 @@
         - if @inbox.empty?
           = t 'views.inbox.empty'
 
-      #pagination= will_paginate @inbox, renderer: BootstrapPagination::Rails, page_links: false
+      = render 'shared/cursored_pagination_dummy', more_data_available: @more_data_available, last_id: @inbox_last_id
 
-      - if @inbox.next_page
-        %button#load-more-btn.btn.btn-default{type: :button, data: { current_page: @inbox.current_page }}
+      - if @more_data_available
+        %button#load-more-btn.btn.btn-default{type: :button, data: { last_id: @inbox_last_id }}
           = t 'views.actions.load'
 
     .col-md-9.col-xs-12.col-sm-8.visible-xs

app/views/inbox/show.js.erb

@@ -1,9 +1,9 @@
 $('#entries').append('<% @inbox.each do |i|
   %><%= j render 'inbox/entry', i: i
 %><% end %>');
-<% if @inbox.next_page %>
-$('#pagination').html('<%= j will_paginate @inbox, renderer: BootstrapPagination::Rails, page_links: false %>');
+<% if @more_data_available %>
+$('#pagination').html('<%= j render 'shared/cursored_pagination_dummy', more_data_available: @more_data_available, last_id: @inbox_last_id %>');
 <% else %>
 $('#pagination, #load-more-btn').remove();
 <% end %>
-<% Inbox.where(id: @inbox.pluck(:id)).update_all(new: false) %>
+<% Inbox.where(id: @inbox.pluck(:id)).update_all(new: false) %>

app/views/notifications/index.html.haml

@@ -18,9 +18,9 @@
           - @notifications.each do |notification|
             = render 'notifications/notification', notification: notification
 
-    #pagination= will_paginate @notifications, renderer: BootstrapPagination::Rails, page_links: false
+    = render 'shared/cursored_pagination_dummy', more_data_available: @more_data_available, last_id: @notifications_last_id, permitted_params: %i[type]
 
-    - if @notifications.next_page
-      %button#load-more-btn.btn.btn-default{type: :button, data: { current_page: @notifications.current_page }}
+    - if @more_data_available
+      %button#load-more-btn.btn.btn-default{type: :button, data: { last_id: @notifications_last_id }}
         Load more
 - Notification.for(current_user).update_all(new: false)

app/views/notifications/index.js.erb

@@ -1,8 +1,8 @@
 $('#notifications').append('<% @notifications.each do |notification|
   %><%= j render 'notifications/notification', notification: notification
 %><% end %>');
-<% if @notifications.next_page %>
-  $('#pagination').html('<%= j will_paginate @notifications, renderer: BootstrapPagination::Rails, page_links: false %>');
+<% if @more_data_available %>
+  $('#pagination').html('<%= j render 'shared/cursored_pagination_dummy', more_data_available: @more_data_available, last_id: @notifications_last_id, permitted_params: %i[type] %>');
 <% else %>
   $('#pagination, #load-more-btn').remove();
-<% end %>
+<% end %>

app/views/public/index.html.haml

@@ -10,9 +10,9 @@
       - @timeline.each do |answer|
         = render 'shared/answerbox', a: answer
 
-    #pagination= will_paginate @timeline, renderer: BootstrapPagination::Rails, page_links: false
+    = render 'shared/cursored_pagination_dummy', more_data_available: @more_data_available, last_id: @timeline_last_id
 
-    - if @timeline.next_page
-      %button#load-more-btn.btn.btn-default{type: :button, data: { current_page: @timeline.current_page }}
+    - if @more_data_available
+      %button#load-more-btn.btn.btn-default{type: :button, data: { last_id: @timeline_last_id }}
         Load more
 .visible-xs= render 'shared/links'

app/views/public/index.js.erb

@@ -1,8 +1,8 @@
 $('#timeline').append('<% @timeline.each do |answer|
   %><%= j render 'shared/answerbox', a: answer
 %><% end %>');
-<% if @timeline.next_page %>
-  $('#pagination').html('<%= j will_paginate @timeline, renderer: BootstrapPagination::Rails, page_links: false %>');
+<% if @more_data_available %>
+  $('#pagination').html('<%= j render 'shared/cursored_pagination_dummy', more_data_available: @more_data_available, last_id: @timeline_last_id %>');
 <% else %>
   $('#pagination, #load-more-btn').remove();
-<% end %>
+<% end %>

app/views/question/show.html.haml

@@ -8,10 +8,10 @@
     - @answers.each do |a|
       = render 'shared/answerbox', a: a, show_question: false
 
-  #pagination= will_paginate @answers, renderer: BootstrapPagination::Rails, page_links: false
+  = render 'shared/cursored_pagination_dummy', more_data_available: @more_data_available, last_id: @answers_last_id
 
-  - if @answers.next_page
-    %button#load-more-btn.btn.btn-default{type: :button, data: { current_page: @answers.current_page }}
+  - if @more_data_available
+    %button#load-more-btn.btn.btn-default{type: :button, data: { last_id: @answers_last_id }}
       Load more
 
   - if user_signed_in? and !current_user.answered? @question and current_user != @question.user and @question.user.privacy_allow_stranger_answers

app/views/question/show.js.erb

@@ -1,8 +1,8 @@
 $('#answers').append('<% @answers.each do |answer|
   %><%= j render 'shared/answerbox', a: answer, show_question: false
 %><% end %>');
-<% if @answers.next_page %>
-  $('#pagination').html('<%= j will_paginate @answers, renderer: BootstrapPagination::Rails, page_links: false %>');
+<% if @more_data_available %>
+  $('#pagination').html('<%= j render 'shared/cursored_pagination_dummy', more_data_available: @more_data_available, last_id: @answers_last_id %>');
 <% else %>
   $('#pagination, #load-more-btn').remove();
-<% end %>
+<% end %>

app/views/shared/_cursored_pagination_dummy.haml

@@ -0,0 +1,11 @@
+-# this renders a pagination html to keep compatibility with the current pagination js
+-# it _should_ be replaced with something else entirely later on.
+- permitted_params ||= []
+#pagination
+  %ul.pagination
+    %li.next{class: more_data_available ? nil : "disabled"}
+      - if more_data_available
+        %a{rel: :next, href: url_for(params.permit(*permitted_params).merge(last_id: last_id))}
+          Next page
+      - else
+        Next page

app/views/static/index.html.haml

@@ -9,9 +9,9 @@
       - @timeline.each do |answer|
         = render 'shared/answerbox', a: answer
 
-    #pagination= will_paginate @timeline, renderer: BootstrapPagination::Rails, page_links: false
+    = render 'shared/cursored_pagination_dummy', more_data_available: @more_data_available, last_id: @timeline_last_id
 
-    - if @timeline.next_page
-      %button#load-more-btn.btn.btn-default{type: :button, data: { current_page: @timeline.current_page }}
+    - if @more_data_available
+      %button#load-more-btn.btn.btn-default{type: :button, data: { last_id: @timeline_last_id }}
         Load more
-  .visible-xs= render 'shared/links'
+  .visible-xs= render 'shared/links'

app/views/static/index.js.erb

@@ -1,8 +1,8 @@
 $('#timeline').append('<% @timeline.each do |answer|
   %><%= j render 'shared/answerbox', a: answer
 %><% end %>');
-<% if @timeline.next_page %>
-  $('#pagination').html('<%= j will_paginate @timeline, renderer: BootstrapPagination::Rails, page_links: false %>');
+<% if @more_data_available %>
+  $('#pagination').html('<%= j render 'shared/cursored_pagination_dummy', more_data_available: @more_data_available, last_id: @timeline_last_id %>');
 <% else %>
   $('#pagination, #load-more-btn').remove();
-<% end %>
+<% end %>

app/views/user/questions.html.haml

@@ -13,9 +13,9 @@
       - @questions.each do |q|
         = render 'shared/question', q: q, type: nil
 
-    #pagination= will_paginate @questions, renderer: BootstrapPagination::Rails, page_links: false
+    = render 'shared/cursored_pagination_dummy', more_data_available: @more_data_available, last_id: @questions_last_id
 
-    - if @questions.next_page
-      %button#load-more-btn.btn.btn-default{type: :button, data: { current_page: @questions.current_page }}
+    - if @more_data_available
+      %button#load-more-btn.btn.btn-default{type: :button, data: { last_id: @questions_last_id }}
         = t 'views.actions.load'
   .visible-xs= render 'shared/links'

app/views/user/questions.js.erb

@@ -1,8 +1,8 @@
 $('#questions').append('<% @questions.each do |q|
   %><%= j render 'shared/question', q: q, type: nil
 %><% end %>');
-<% if @questions.next_page %>
-$('#pagination').html('<%= j will_paginate @questions, renderer: BootstrapPagination::Rails, page_links: false %>');
+<% if @more_data_available %>
+$('#pagination').html('<%= j render 'shared/cursored_pagination_dummy', more_data_available: @more_data_available, last_id: @questions_last_id %>');
 <% else %>
 $('#pagination, #load-more-btn').remove();
 <% end %>

app/views/user/show.html.haml

@@ -14,10 +14,10 @@
         - @answers.each do |a|
           = render 'shared/answerbox', a: a
 
-      #pagination= will_paginate @answers, renderer: BootstrapPagination::Rails, page_links: false
+      = render 'shared/cursored_pagination_dummy', more_data_available: @more_data_available, last_id: @answers_last_id
 
-      - if @answers.next_page
-        %button#load-more-btn.btn.btn-default{type: :button, data: { current_page: @answers.current_page }}
+      - if @more_data_available
+        %button#load-more-btn.btn.btn-default{type: :button, data: { last_id: @answers_last_id }}
           = t 'views.actions.load'
   .visible-xs= render 'shared/links'
 - if user_signed_in?

app/views/user/show.js.erb

@@ -1,8 +1,8 @@
 $('#answers').append('<% @answers.each do |a|
   %><%= j render 'shared/answerbox', a: a
 %><% end %>');
-<% if @answers.next_page %>
-  $('#pagination').html('<%= j will_paginate @answers, renderer: BootstrapPagination::Rails, page_links: false %>');
+<% if @more_data_available %>
+  $('#pagination').html('<%= j render 'shared/cursored_pagination_dummy', more_data_available: @more_data_available, last_id: @answers_last_id %>');
 <% else %>
   $('#pagination, #load-more-btn').remove();
-<% end %>
+<% end %>

app/views/user/show_follow.html.haml

@@ -14,10 +14,10 @@
         .col-md-4.col-sm-6.col-xs-12
           = render 'shared/userbox', user: user
 
-    #pagination= will_paginate @users, renderer: BootstrapPagination::Rails, page_links: false
+    = render 'shared/cursored_pagination_dummy', more_data_available: @more_data_available, last_id: @users_last_id
 
-    - if @users.next_page
-      %button#load-more-btn.btn.btn-default{type: :button, data: { current_page: @users.current_page }}
+    - if @more_data_available
+      %button#load-more-btn.btn.btn-default{type: :button, data: { last_id: @users_last_id }}
         = t 'views.actions.load'
   .visible-xs= render 'shared/links'
 - if user_signed_in?

app/views/user/show_follow.js.erb

@@ -1,8 +1,8 @@
 $('#users').append('<% @users.each do |user|
   %><div class="col-md-4 col-sm-6 col-xs-12"><%= j render 'shared/userbox', user: user
 %></div><% end %>');
-<% if @users.next_page %>
-  $('#pagination').html('<%= j will_paginate @users, renderer: BootstrapPagination::Rails, page_links: false %>');
+<% if @more_data_available %>
+  $('#pagination').html('<%= j render 'shared/cursored_pagination_dummy', more_data_available: @more_data_available, last_id: @users_last_id %>');
 <% else %>
   $('#pagination, #load-more-btn').remove();
 <% end %>

config/initializers/20_will_paginate.rb

@@ -1 +0,0 @@
-WillPaginate.per_page = APP_CONFIG['items_per_page']

config/initializers/rails_admin.rb

@@ -1,12 +1,6 @@
 # frozen_string_literal: true
 
 # workaround to get pagination right
-if defined? WillPaginate
-  Kaminari.configure do |config|
-    config.page_method_name = :per_page_kaminari
-  end
-end
-
 RailsAdmin.config do |config|
   config.main_app_name = ['justask', 'Kontrollzentrum']
 

spec/factories/answer.rb

@@ -0,0 +1,12 @@
+# frozen_string_literal: true
+
+FactoryBot.define do
+  factory :answer do
+    transient do
+      question_content { Faker::Lorem.sentence }
+    end
+
+    content { Faker::Lorem.sentence }
+    question { FactoryBot.build(:question, content: question_content) }
+  end
+end

spec/factories/question.rb

@@ -0,0 +1,9 @@
+# frozen_string_literal: true
+
+FactoryBot.define do
+  factory :question do
+    user { nil }
+    content { Faker::Lorem.sentence }
+    author_is_anonymous { true }
+  end
+end

spec/factories/user.rb

@@ -2,9 +2,9 @@
 
 FactoryBot.define do
   factory :user do
-    sequence(:screen_name) { |i| "#{Faker::Internet.username(specifier: 0..12, separators: %w(_))}#{i}" }
+    sequence(:screen_name) { |i| "#{Faker::Internet.username(specifier: 0..12, separators: %w[_])}#{i}" }
     sequence(:email) { |i| "#{i}#{Faker::Internet.email}" }
-    password { "P4s5w0rD" }
+    password { 'P4s5w0rD' }
     confirmed_at { Time.now.utc }
     display_name { Faker::Name.name }
 

spec/models/user_spec.rb

@@ -1,28 +1,158 @@
+# frozen_string_literal: true
+
 require 'rails_helper'
 
-RSpec.describe User, :type => :model do
-  before :each do
-    @user = User.new(
+RSpec.describe User, type: :model do
+  let!(:me) { FactoryBot.create :user }
+
+  describe 'basic assigns' do
+    before :each do
+      @user = User.new(
         screen_name: 'FunnyMeme2004',
         password: 'y_u_no_secure_password?',
         email: 'nice.meme@nsa.gov'
-    )
+      )
+    end
+
+    subject { @user }
+
+    it { should respond_to(:email) }
+
+    it '#email returns a string' do
+      expect(@user.email).to match 'nice.meme@nsa.gov'
+    end
+
+    it '#motivation_header has a default value' do
+      expect(@user.motivation_header).to match ''
+    end
+
+    it 'does not save an invalid screen name' do
+      @user.screen_name = '$Funny-Meme-%&2004'
+      expect { @user.save! }.to raise_error(ActiveRecord::RecordInvalid)
+    end
   end
 
-  subject { @user }
+  # -- User::TimelineMethods --
 
-  it { should respond_to(:email) }
-
-  it '#email returns a string' do
-    expect(@user.email).to match 'nice.meme@nsa.gov'
+  shared_examples_for 'result is blank' do
+    it 'result is blank' do
+      expect(subject).to be_blank
+    end
   end
 
-  it '#motivation_header has a default value' do
-    expect(@user.motivation_header).to match ''
+  describe '#timeline' do
+    subject { me.timeline }
+
+    context 'user answered nothing and is not following anyone' do
+      include_examples 'result is blank'
+    end
+
+    context 'user answered something and is not following anyone' do
+      let(:answer) { FactoryBot.create(:answer, user: me) }
+
+      let(:expected) { [answer] }
+
+      it 'includes the answer' do
+        expect(subject).to eq(expected)
+      end
+    end
+
+    context 'user answered something and follows users with answers' do
+      let(:user1) { FactoryBot.create(:user) }
+      let(:user2) { FactoryBot.create(:user) }
+      let(:answer1) { FactoryBot.create(:answer, user: user1, created_at: 12.hours.ago) }
+      let(:answer2) { FactoryBot.create(:answer, user: me, created_at: 1.day.ago) }
+      let(:answer3) { FactoryBot.create(:answer, user: user2, created_at: 10.minutes.ago) }
+      let(:answer4) { FactoryBot.create(:answer, user: user1, created_at: Time.now.utc) }
+
+      let!(:expected) do
+        [answer4, answer3, answer1, answer2]
+      end
+
+      before(:each) do
+        me.follow(user1)
+        me.follow(user2)
+      end
+
+      it 'includes all answers' do
+        expect(subject).to include(answer1)
+        expect(subject).to include(answer2)
+        expect(subject).to include(answer3)
+        expect(subject).to include(answer4)
+      end
+
+      it 'result is ordered by created_at in reverse order' do
+        expect(subject).to eq(expected)
+      end
+    end
   end
 
-  it 'does not save an invalid screen name' do
-    @user.screen_name = '$Funny-Meme-%&2004'
-    expect{@user.save!}.to raise_error(ActiveRecord::RecordInvalid)
+  describe '#cursored_timeline' do
+    let(:last_id) { nil }
+
+    subject { me.cursored_timeline(last_id: last_id, size: 3) }
+
+    context 'user answered nothing and is not following anyone' do
+      include_examples 'result is blank'
+    end
+
+    context 'user answered something and is not following anyone' do
+      let(:answer) { FactoryBot.create(:answer, user: me) }
+
+      let(:expected) { [answer] }
+
+      it 'includes the answer' do
+        expect(subject).to eq(expected)
+      end
+    end
+
+    context 'user answered something and follows users with answers' do
+      let(:user1) { FactoryBot.create(:user) }
+      let(:user2) { FactoryBot.create(:user) }
+      let!(:answer1) { FactoryBot.create(:answer, user: me, created_at: 1.day.ago) }
+      let!(:answer2) { FactoryBot.create(:answer, user: user1, created_at: 12.hours.ago) }
+      let!(:answer3) { FactoryBot.create(:answer, user: user2, created_at: 10.minutes.ago) }
+      let!(:answer4) { FactoryBot.create(:answer, user: user1, created_at: Time.now.utc) }
+
+      before(:each) do
+        me.follow(user1)
+        me.follow(user2)
+      end
+
+      context 'last_id is nil' do
+        let(:last_id) { nil }
+        let(:expected) do
+          [answer4, answer3, answer2]
+        end
+
+        it 'includes three answers' do
+          expect(subject).not_to include(answer1)
+          expect(subject).to include(answer2)
+          expect(subject).to include(answer3)
+          expect(subject).to include(answer4)
+        end
+
+        it 'result is ordered by created_at in reverse order' do
+          expect(subject).to eq(expected)
+        end
+      end
+
+      context 'last_id is answer2.id' do
+        let(:last_id) { answer2.id }
+
+        it 'includes answer1' do
+          expect(subject).to include(answer1)
+          expect(subject).not_to include(answer2)
+          expect(subject).not_to include(answer3)
+          expect(subject).not_to include(answer4)
+        end
+      end
+
+      context 'last_id is answer1.id' do
+        let(:last_id) { answer1.id }
+
+        include_examples 'result is blank'
+      end
+    end
   end
 end