Add email subscriptions (#38163)

app/controllers/unsubscriptions_controller.rb

@@ -0,0 +1,58 @@
+# frozen_string_literal: true
+
+class UnsubscriptionsController < ApplicationController
+  layout 'auth'
+
+  skip_before_action :require_functional!
+
+  before_action :set_recipient
+  before_action :set_type
+  before_action :set_scope
+  before_action :require_type_if_user!
+
+  protect_from_forgery with: :null_session
+
+  def show; end
+
+  def create
+    case @scope
+    when :user
+      @recipient.settings[@type] = false
+      @recipient.save!
+    when :email_subscription
+      @recipient.destroy!
+    end
+  end
+
+  private
+
+  def set_recipient
+    @recipient = GlobalID::Locator.locate_signed(params[:token], for: 'unsubscribe')
+    not_found unless @recipient
+  end
+
+  def set_scope
+    if @recipient.is_a?(User)
+      @scope = :user
+    elsif @recipient.is_a?(EmailSubscription)
+      @scope = :email_subscription
+    else
+      not_found
+    end
+  end
+
+  def set_type
+    @type = email_type_from_param
+  end
+
+  def require_type_if_user!
+    not_found if @recipient.is_a?(User) && @type.blank?
+  end
+
+  def email_type_from_param
+    case params[:type]
+    when 'follow', 'reblog', 'favourite', 'mention', 'follow_request'
+      "notification_emails.#{params[:type]}"
+    end
+  end
+end