Migrate user identity matching off stem user id drupal

app/controllers/api/users_controller.rb

@@ -9,7 +9,11 @@ def show
     end
 
     def forget
-      user = User.find_by!(stem_user_id: params[:stem_user_id])
+      user = if params[:stem_achiever_contact_no].present?
+        User.find_by!(stem_achiever_contact_no: params[:stem_achiever_contact_no])
+      else
+        User.find_by!(stem_user_id: params[:stem_user_id])
+      end
       user.forget!
       render json: as_json(user)
     end

app/controllers/auth_controller.rb

@@ -3,7 +3,7 @@ def callback
     auth = omniauth_params
     course_booking_uri = course_redirect_params
 
-    user_exists = User.exists?(stem_user_id: auth.info.stem_user_id)
+    user_exists = User.exists?(stem_achiever_contact_no: auth.info.achiever_contact_no)
     user = User.from_auth(auth.uid, auth.credentials, auth.info)
 
     session[:user_id] = user.id

app/models/user.rb

@@ -4,10 +4,10 @@
 class User < ApplicationRecord
   validates :first_name, presence: true
   validates :last_name, presence: true
-  validates :stem_achiever_contact_no, presence: true
+  validates :stem_achiever_contact_no, presence: true, uniqueness: true
   validates :stem_credentials_access_token, presence: true
   validates :stem_credentials_expires_at, presence: true
-  validates :stem_user_id, presence: true, uniqueness: true
+  validates :stem_user_id, uniqueness: true, allow_nil: true
   # WARNING: We are consiously choosing not to have a unique constraint on
   # emails
   validates :email, presence: true
@@ -35,7 +35,7 @@ class User < ApplicationRecord
   alias_method :support_audits, :audits
 
   def self.from_auth(id, credentials, info)
-    user = where(stem_user_id: info.stem_user_id).first_or_initialize
+    user = where(stem_achiever_contact_no: info.achiever_contact_no).first_or_initialize
 
     users_with_new_email_count = User.where(email: info.email.downcase).count
 
@@ -50,7 +50,7 @@ def self.from_auth(id, credentials, info)
     end
 
     user.auth0_id = id
-    user.stem_user_id = info.stem_user_id
+    user.stem_user_id = info.stem_user_id if info.stem_user_id.present?
     user.first_name = info.first_name
     user.last_name = info.last_name
     user.email = info.email.downcase

db/migrate/20260819124651_make_user_stem_user_id_nullable_on_user_report_entries.rb

@@ -0,0 +1,5 @@
+class MakeUserStemUserIdNullableOnUserReportEntries < ActiveRecord::Migration[8.1]
+  def change
+    change_column_null :user_report_entries, :user_stem_user_id, true
+  end
+end

db/migrate/20260820090000_add_unique_index_to_users_stem_achiever_contact_no.rb

@@ -0,0 +1,5 @@
+class AddUniqueIndexToUsersStemAchieverContactNo < ActiveRecord::Migration[8.1]
+  def change
+    add_index :users, :stem_achiever_contact_no, unique: true
+  end
+end