chore: Contact import improvements (#7787)

- Ensure existing contact information is updated on data import
- Refactor the existing job to make it more readable
- Fixes issues with import files in the wrong encoding
fixes: #7307

app/jobs/data_import_job.rb

@@ -6,15 +6,15 @@ class DataImportJob < ApplicationJob
 
   def perform(data_import)
     @data_import = data_import
+    @contact_manager = DataImport::ContactManager.new(@data_import.account)
     process_import_file
-    send_failed_records_to_admin
+    send_import_notification_to_admin
   end
 
   private
 
   def process_import_file
     @data_import.update!(status: :processing)
-
     contacts, rejected_contacts = parse_csv_and_build_contacts
 
     import_contacts(contacts)
@@ -25,21 +25,28 @@ class DataImportJob < ApplicationJob
   def parse_csv_and_build_contacts
     contacts = []
     rejected_contacts = []
-    csv = CSV.parse(@data_import.import_file.download, headers: true)
+    # Ensuring that importing non utf-8 characters will not throw error
+    data = @data_import.import_file.download
+    clean_data = data.encode('UTF-8', 'binary', invalid: :replace, undef: :replace, replace: '')
+    csv = CSV.parse(clean_data, headers: true)
 
     csv.each do |row|
-      current_contact = build_contact(row.to_h.with_indifferent_access, @data_import.account)
+      current_contact = @contact_manager.build_contact(row.to_h.with_indifferent_access)
       if current_contact.valid?
         contacts << current_contact
       else
-        row['errors'] = current_contact.errors.full_messages.join(', ')
-        rejected_contacts << row
+        append_rejected_contact(row, current_contact, rejected_contacts)
       end
     end
 
     [contacts, rejected_contacts]
   end
 
+  def append_rejected_contact(row, contact, rejected_contacts)
+    row['errors'] = contact.errors.full_messages.join(', ')
+    rejected_contacts << row
+  end
+
   def import_contacts(contacts)
     # <struct ActiveRecord::Import::Result failed_instances=[], num_inserts=1, ids=[444, 445], results=[]>
     Contact.import(contacts, synchronize: contacts, on_duplicate_key_ignore: true, track_validation_failures: true, validate: true, batch_size: 1000)
@@ -49,63 +56,13 @@ class DataImportJob < ApplicationJob
     @data_import.update!(status: :completed, processed_records: processed_records, total_records: processed_records + rejected_records)
   end
 
-  def build_contact(params, account)
-    contact = find_or_initialize_contact(params, account)
-    contact.name = params[:name] if params[:name].present?
-    contact.additional_attributes ||= {}
-    contact.additional_attributes[:company] = params[:company] if params[:company].present?
-    contact.additional_attributes[:city] = params[:city] if params[:city].present?
-    contact.assign_attributes(custom_attributes: contact.custom_attributes.merge(params.except(:identifier, :email, :name, :phone_number)))
-    contact
-  end
-
-  def find_or_initialize_contact(params, account)
-    contact = find_existing_contact(params, account)
-    contact ||= account.contacts.new(params.slice(:email, :identifier, :phone_number))
-    contact
-  end
-
-  def find_existing_contact(params, account)
-    contact = find_contact_by_identifier(params, account)
-    contact ||= find_contact_by_email(params, account)
-    contact ||= find_contact_by_phone_number(params, account)
-
-    update_contact_with_merged_attributes(params, contact) if contact.present? && contact.valid?
-    contact
-  end
-
-  def find_contact_by_identifier(params, account)
-    return unless params[:identifier]
-
-    account.contacts.find_by(identifier: params[:identifier])
-  end
-
-  def find_contact_by_email(params, account)
-    return unless params[:email]
-
-    account.contacts.find_by(email: params[:email])
-  end
-
-  def find_contact_by_phone_number(params, account)
-    return unless params[:phone_number]
-
-    account.contacts.find_by(phone_number: params[:phone_number])
-  end
-
-  def update_contact_with_merged_attributes(params, contact)
-    contact.email = params[:email] if params[:email].present?
-    contact.phone_number = params[:phone_number] if params[:phone_number].present?
-    contact.save
-  end
-
   def save_failed_records_csv(rejected_contacts)
     csv_data = generate_csv_data(rejected_contacts)
-
     return if csv_data.blank?
 
     @data_import.failed_records.attach(io: StringIO.new(csv_data), filename: "#{Time.zone.today.strftime('%Y%m%d')}_contacts.csv",
                                        content_type: 'text/csv')
-    send_failed_records_to_admin
+    send_import_notification_to_admin
   end
 
   def generate_csv_data(rejected_contacts)
@@ -121,7 +78,7 @@ class DataImportJob < ApplicationJob
     end
   end
 
-  def send_failed_records_to_admin
-    AdministratorNotifications::ChannelNotificationsMailer.with(account: @data_import.account).failed_records(@data_import).deliver_later
+  def send_import_notification_to_admin
+    AdministratorNotifications::ChannelNotificationsMailer.with(account: @data_import.account).contact_import_complete(@data_import).deliver_later
   end
 end