Add language when new user visit context is detected (#20263)

* Add language when new user visit context is detected

* Finalize tests

app/models/user_visit_context.rb

@@ -1,4 +1,27 @@
 class UserVisitContext < ApplicationRecord
   belongs_to :user
   has_many :ahoy_visits, class_name: "Ahoy::Visit", dependent: :nullify
+
+  after_create :set_user_language
+
+  def set_user_language
+    # When we detect a new user context, we automatically
+    # add languages with a weight of greater than 0.7
+    languages = accept_language.split(",")
+
+    languages.map! do |lang|
+      lang, q = lang.split(";q=")
+      [lang[0..1], (q || "1").to_f]
+    end
+
+    filtered_languages = languages
+      .select { |_, q| q >= 0.7 }
+      .uniq { |lang, _| lang }
+
+    filtered_languages.map(&:first).each do |lang|
+      UserLanguage.where(user_id: user_id, language: lang).first_or_create
+    end
+  rescue StandardError => e
+    Rails.logger.error(e)
+  end
 end

spec/models/user_visit_context_spec.rb

@@ -1,5 +1,41 @@
-require 'rails_helper'
+require "rails_helper"
 
-RSpec.describe UserVisitContext, type: :model do
-  pending "add some examples to (or delete) #{__FILE__}"
+RSpec.describe UserVisitContext do
+  describe "associations" do
+    it { is_expected.to belong_to(:user) }
+    it { is_expected.to have_many(:ahoy_visits).class_name("Ahoy::Visit").dependent(:nullify) }
+  end
+
+  describe "callbacks" do
+    let(:user) { create(:user) }
+    let(:user_visit_context) { build(:user_visit_context, user: user) }
+
+    it "calls set_user_language after create" do
+      allow(user_visit_context).to receive(:set_user_language)
+      user_visit_context.save!
+      expect(user_visit_context).to have_received(:set_user_language)
+    end
+  end
+
+  describe "#set_user_language" do
+    let(:user) { create(:user) }
+    let(:user_visit_context) { build(:user_visit_context, user: user, accept_language: "en-US;q=0.9,fr-FR;q=0.8") }
+
+    it "creates UserLanguage records" do
+      expect { user_visit_context.set_user_language }
+        .to change(UserLanguage, :count).by(2)
+    end
+
+    it "logs an error if something goes wrong" do
+      allow(UserLanguage).to receive(:where).and_raise(StandardError)
+      allow(Rails.logger).to receive(:error).with(instance_of(StandardError))
+      user_visit_context.set_user_language
+      expect(Rails.logger).to have_received(:error).with(instance_of(StandardError))
+    end
+
+    it "matches specific languages" do
+      user_visit_context.set_user_language
+      expect(UserLanguage.pluck(:language)).to match_array(%w[en fr])
+    end
+  end
 end