Bring timezone support to user model

app/jobs/one_time/set_user_timezone_from_slack_job.rb

@@ -4,26 +4,8 @@ class OneTime::SetUserTimezoneFromSlackJob < ApplicationJob
   def perform
     User.where.not(slack_uid: nil).find_each(batch_size: 100) do |user|
       begin
-        user_response = HTTP.auth("Bearer #{user.slack_access_token}")
-          .get("https://slack.com/api/users.info?user=#{user.slack_uid}")
-
-        user_data = JSON.parse(user_response.body.to_s)
-
-        next unless user_data["ok"]
-
-        timezone = user_data.dig("user", "tz")
-        next unless timezone.present?
-
-        # Convert IANA timezone to ActiveSupport timezone
-        begin
-          tz = ActiveSupport::TimeZone.find_tzinfo(timezone)
-          user.update!(
-            timezone: tz.name,
-          )
-          Rails.logger.info "Updated timezone for user #{user.id} to #{tz.name}"
-        rescue TZInfo::InvalidTimezoneIdentifier => e
-          Rails.logger.error "Invalid timezone #{timezone} for user #{user.id}: #{e.message}"
-        end
+        user.set_timezone_from_slack
+        user.save!
       rescue => e
         Rails.logger.error "Failed to update timezone for user #{user.id}: #{e.message}"
       end

app/models/user.rb

@@ -47,6 +47,32 @@ class User < ApplicationRecord
     end
   end
 
+  def set_timezone_from_slack
+    return unless slack_uid.present?
+
+    user_response = HTTP.auth("Bearer #{slack_access_token}")
+      .get("https://slack.com/api/users.info?user=#{slack_uid}")
+
+    user_data = JSON.parse(user_response.body.to_s)
+
+    return unless user_data["ok"]
+
+    timezone_string = user_data.dig("user", "tz")
+
+    return unless timezone_string.present?
+
+    parse_and_set_timezone(timezone_string)
+  end
+
+  def parse_and_set_timezone(timezone)
+    begin
+      tz = ActiveSupport::TimeZone.find_tzinfo(timezone)
+      self.timezone = tz.name
+    rescue TZInfo::InvalidTimezoneIdentifier => e
+      Rails.logger.error "Invalid timezone #{timezone} for user #{id}: #{e.message}"
+    end
+  end
+
   def admin?
     is_admin
   end