Make relationships polymorphic

app/controllers/user_controller.rb

@@ -10,7 +10,7 @@ class UserController < ApplicationController
     @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
+      notif = Notification.where(target_type: "Relationship", target_id: @user.active_follow_relationships.where(target_id: current_user.id).pluck(:id), recipient_id: current_user.id, new: true).first
       unless notif.nil?
         notif.new = false
         notif.save
@@ -96,12 +96,12 @@ class UserController < ApplicationController
     end
   end
 
-  def friends
+  def followings
     @title = 'Following'
     @user = User.where('LOWER(screen_name) = ?', params[:username].downcase).includes(:profile).first!
-    @users = @user.cursored_friends(last_id: params[:last_id])
+    @users = @user.cursored_followings(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?
+    @more_data_available = !@user.cursored_followings(last_id: @users_last_id, size: 1).count.zero?
     @type = :friend
 
     respond_to do |format|

app/models/relationship.rb

@@ -5,24 +5,4 @@ class Relationship < ApplicationRecord
   validates :target_id, presence: true
 
   default_scope { order(created_at: :asc) }
-
-  after_create do
-    Notification.notify target, self
-
-    # increment counts
-    source.increment! :friend_count
-    target.increment! :follower_count
-  end
-
-  before_destroy do
-    Notification.denotify target, self
-
-    # decrement counts
-    source.decrement! :friend_count
-    target.decrement! :follower_count
-  end
-
-  def notification_type(*_args)
-    Notifications::StartedFollowing
-  end
 end

app/models/relationships/follow.rb

@@ -0,0 +1,19 @@
+class Relationships::Follow < Relationship
+  after_create do
+    Notification.notify target, self
+    # increment counts
+    source.increment! :friend_count
+    target.increment! :follower_count
+  end
+
+  before_destroy do
+    Notification.denotify target, self
+    # decrement counts
+    source.decrement! :friend_count
+    target.decrement! :follower_count
+  end
+
+  def notification_type(*_args)
+    Notifications::StartedFollowing
+  end
+end

app/models/user.rb

@@ -1,4 +1,6 @@
 class User < ApplicationRecord
+  include User::Relationship
+  include User::Relationship::Follow
   include User::AnswerMethods
   include User::InboxMethods
   include User::QuestionMethods
@@ -24,14 +26,6 @@ class User < ApplicationRecord
   has_many :answers, dependent: :destroy
   has_many :comments, dependent: :destroy
   has_many :inboxes, dependent: :destroy
-  has_many :active_relationships, class_name: 'Relationship',
-                                  foreign_key: 'source_id',
-                                  dependent: :destroy
-  has_many :passive_relationships, class_name: 'Relationship',
-                                   foreign_key: 'target_id',
-                                   dependent: :destroy
-  has_many :friends,   through: :active_relationships, source: :target
-  has_many :followers, through: :passive_relationships, source: :source
   has_many :smiles, dependent: :destroy
   has_many :comment_smiles, dependent: :destroy
   has_many :services, dependent: :destroy
@@ -111,11 +105,6 @@ class User < ApplicationRecord
     active_relationships.find_by(target: target_user).destroy
   end
 
-  # @return [Boolean] true if +self+ is following +target_user+
-  def following?(target_user)
-    friends.include? target_user
-  end
-
   # @param list [List]
   # @return [Boolean] true if +self+ is a member of +list+
   def member_of?(list)

app/models/user/relationship.rb

@@ -0,0 +1,23 @@
+# frozen_string_literal: true
+
+class User
+  module Relationship
+    extend ActiveSupport::Concern
+
+    private
+
+    # Create a relationship for `type` with `target_user` as target.
+    def create_relationship(type, target_user)
+      type.create(target: target_user)
+    end
+
+    # Destroy a relationship for `type` with `target_user` as target.
+    def destroy_relationship(type, target_user)
+      type.find_by(target: target_user)&.destroy
+    end
+
+    def relationship_active?(type, target_user)
+      type.include?(target_user)
+    end
+  end
+end

app/models/user/relationship/follow.rb

@@ -0,0 +1,39 @@
+# frozen_string_literal: true
+
+require "errors"
+
+class User
+  module Relationship
+    module Follow
+      extend ActiveSupport::Concern
+
+      included do
+        has_many :active_follow_relationships, class_name: "Relationships::Follow",
+                                               foreign_key: "source_id",
+                                               dependent: :destroy
+        has_many :passive_follow_relationships, class_name: "Relationships::Follow",
+                                                foreign_key: "target_id",
+                                                dependent: :destroy
+        has_many :followings, through: :active_follow_relationships, source: :target
+        has_many :followers,  through: :passive_follow_relationships, source: :source
+      end
+
+      # Follow an user
+      def follow(target_user)
+        raise Justask::Errors::FollowingOtherBlockedSelf if target_user.blocking?(self)
+        raise Justask::Errors::FollowingSelfBlockedOther if blocking?(target_user)
+        raise Justask::Errors::FollowingSelf if target_user == self
+        create_relationship(active_follow_relationships, target_user)
+      end
+
+      # Unfollow an user
+      def unfollow(target_user)
+        destroy_relationship(active_follow_relationships, target_user)
+      end
+
+      def following?(target_user)
+        relationship_active?(followings, target_user)
+      end
+    end
+  end
+end

app/models/user/relationship_methods.rb

@@ -3,11 +3,11 @@
 module User::RelationshipMethods
   include CursorPaginatable
 
-  define_cursor_paginator :cursored_friends, :ordered_friends
+  define_cursor_paginator :cursored_followings, :ordered_followings
   define_cursor_paginator :cursored_followers, :ordered_followers
 
-  def ordered_friends
-    friends.reverse_order.includes(:profile)
+  def ordered_followings
+    followings.reverse_order.includes(:profile)
   end
 
   def ordered_followers

app/models/user/timeline_methods.rb

@@ -7,6 +7,6 @@ module User::TimelineMethods
 
   # @return [Array] the users' timeline
   def timeline
-    Answer.where('user_id in (?) OR user_id = ?', friend_ids, id).order(:created_at).reverse_order.includes(comments: [:user, :smiles], question: [:user], user: [:profile], smiles: [:user])
+    Answer.where('user_id in (?) OR user_id = ?', following_ids, id).order(:created_at).reverse_order.includes(comments: [:user, :smiles], question: [:user], user: [:profile], smiles: [:user])
   end
 end

app/views/tabs/_profile.haml

@@ -2,5 +2,5 @@
   .list-group.list-group-horizontal-sm.text-center
     = list_group_item 'Answers', show_user_profile_path(user.screen_name), badge: user.answered_count
     = list_group_item 'Questions', show_user_questions_path(user.screen_name), badge: user.asked_count
-    = list_group_item 'Followers', show_user_followers_path(user.screen_name), badge: user.follower_count
-    = list_group_item 'Following', show_user_friends_path(user.screen_name), badge: user.friend_count
+    = list_group_item 'Followers', show_user_followers_path(user.screen_name), badge: user.followers.count
+    = list_group_item 'Following', show_user_followings_path(user.screen_name), badge: user.followings.count

config/routes.rb

@@ -135,12 +135,12 @@ Rails.application.routes.draw do
   match '/@:username/a/:id', to: 'answer#show', via: 'get', as: :show_user_answer_alt
   match '/@:username/q/:id', to: 'question#show', via: 'get', as: :show_user_question_alt
   match '/@:username/followers(/p/:page)', to: 'user#followers', via: 'get', as: :show_user_followers_alt, defaults: {page: 1}
-  match '/@:username/friends(/p/:page)', to: 'user#friends', via: 'get', as: :show_user_friends_alt, defaults: {page: 1}
+  match '/@:username/followings(/p/:page)', to: 'user#followings', via: 'get', as: :show_user_followings_alt, defaults: {page: 1}
   match '/:username(/p/:page)', to: 'user#show', via: 'get', as: :show_user_profile, defaults: {page: 1}
   match '/:username/a/:id', to: 'answer#show', via: 'get', as: :show_user_answer
   match '/:username/q/:id', to: 'question#show', via: 'get', as: :show_user_question
   match '/:username/followers(/p/:page)', to: 'user#followers', via: 'get', as: :show_user_followers, defaults: {page: 1}
-  match '/:username/friends(/p/:page)', to: 'user#friends', via: 'get', as: :show_user_friends, defaults: {page: 1}
+  match '/:username/followings(/p/:page)', to: 'user#followings', via: 'get', as: :show_user_followings, defaults: {page: 1}
   match '/:username/lists(/p/:page)', to: 'user#lists', via: 'get', as: :show_user_lists, defaults: {page: 1}
   match '/:username/questions(/p/:page)', to: 'user#questions', via: 'get', as: :show_user_questions, defaults: {page: 1}
 

db/migrate/20211231155702_add_type_to_relationships.rb

@@ -0,0 +1,16 @@
+class AddTypeToRelationships < ActiveRecord::Migration[5.2]
+  def up
+    add_column :relationships, :type, :string
+
+    execute %(update relationships set type = 'Relationships::Follow')
+
+    change_column_null :relationships, :type, false
+    add_index :relationships, :type
+  end
+
+  def down
+    execute %(delete from relationships where type <> 'Relationships::Follow')
+
+    remove_column :relationships, :type
+  end
+end

db/schema.rb

@@ -157,9 +157,11 @@ ActiveRecord::Schema.define(version: 2022_01_05_171216) do
     t.bigint "target_id"
     t.datetime "created_at"
     t.datetime "updated_at"
+    t.string "type", null: false
     t.index ["source_id", "target_id"], name: "index_relationships_on_source_id_and_target_id", unique: true
     t.index ["source_id"], name: "index_relationships_on_source_id"
     t.index ["target_id"], name: "index_relationships_on_target_id"
+    t.index ["type"], name: "index_relationships_on_type"
   end
 
   create_table "reports", id: :serial, force: :cascade do |t|

spec/controllers/ajax/friend_controller_spec.rb

@@ -28,9 +28,9 @@ describe Ajax::FriendController, :ajax_controller, type: :controller do
         end
 
         it "creates a follow relationship" do
-          expect(user.friends.ids).not_to include(target_user.id)
-          expect { subject }.to(change { user.friends.count }.by(1))
-          expect(user.friends.ids).to include(target_user.id)
+          expect(user.followings.ids).not_to include(target_user.id)
+          expect { subject }.to(change { user.followings.count }.by(1))
+          expect(user.followings.ids).to include(target_user.id)
         end
 
         include_examples "returns the expected response"
@@ -48,7 +48,7 @@ describe Ajax::FriendController, :ajax_controller, type: :controller do
         end
 
         it "does not create a follow relationship" do
-          expect { subject }.not_to(change { user.friends.count })
+          expect { subject }.not_to(change { user.followings.count })
         end
 
         include_examples "returns the expected response"
@@ -99,9 +99,9 @@ describe Ajax::FriendController, :ajax_controller, type: :controller do
           before(:each) { user.follow target_user }
 
           it "destroys a follow relationship" do
-            expect(user.friends.ids).to include(target_user.id)
-            expect { subject }.to(change { user.friends.count }.by(-1))
-            expect(user.friends.ids).not_to include(target_user.id)
+            expect(user.followings.ids).to include(target_user.id)
+            expect { subject }.to(change { user.followings.count }.by(-1))
+            expect(user.followings.ids).not_to include(target_user.id)
           end
 
           include_examples "returns the expected response"
@@ -117,7 +117,7 @@ describe Ajax::FriendController, :ajax_controller, type: :controller do
           end
 
           it "does not destroy a follow relationship" do
-            expect { subject }.not_to(change { user.friends.count })
+            expect { subject }.not_to(change { user.followings.count })
           end
 
           include_examples "returns the expected response"
@@ -136,7 +136,7 @@ describe Ajax::FriendController, :ajax_controller, type: :controller do
         end
 
         it "does not destroy a follow relationship" do
-          expect { subject }.not_to(change { user.friends.count })
+          expect { subject }.not_to(change { user.followings.count })
         end
 
         include_examples "returns the expected response"