Create a helper to map the settings tab.

This is necessary because we need to map the specific values too and not just the keys in some cases like for the 'subtotal_mismatch_behavior'

modules/ppcp-compat/src/Settings/SettingsTabMapHelper.php

@@ -0,0 +1,73 @@
+<?php
+/**
+ * A helper for mapping the old/new settings tab settings.
+ *
+ * @package WooCommerce\PayPalCommerce\Compat\Settings
+ */
+
+declare(strict_types=1);
+
+namespace WooCommerce\PayPalCommerce\Compat\Settings;
+
+use WooCommerce\PayPalCommerce\ApiClient\Helper\PurchaseUnitSanitizer;
+use WooCommerce\PayPalCommerce\Button\Helper\ContextTrait;
+
+/**
+ * A map of old to new styling settings.
+ *
+ * @psalm-import-type newSettingsKey from SettingsMap
+ * @psalm-import-type oldSettingsKey from SettingsMap
+ */
+class SettingsTabMapHelper {
+
+	use ContextTrait;
+
+	/**
+	 * Maps old setting keys to new setting keys.
+	 *
+	 * @psalm-return array<oldSettingsKey, newSettingsKey>
+	 */
+	public function map(): array {
+		return array(
+			'disable_cards'              => 'disabled_cards',
+			'brand_name'                 => 'brand_name',
+			'soft_descriptor'            => 'soft_descriptor',
+			'subtotal_mismatch_behavior' => 'subtotal_adjustment',
+		);
+	}
+
+	/**
+	 * Retrieves the value of a mapped key from the new settings.
+	 *
+	 * @param string $old_key The key from the legacy settings.
+	 * @param array<string, scalar|array> $settings_model The new settings model data as an array.
+	 * @return mixed The value of the mapped setting, (null if not found).
+	 */
+	public function mapped_value( string $old_key, array $settings_model ) {
+		$settings_map = $this->map();
+		$new_key      = $settings_map[ $old_key ] ?? false;
+		switch ( $old_key ) {
+			case 'subtotal_mismatch_behavior':
+				return $this->mapped_mismatch_behavior_value( $settings_model );
+
+			default:
+				return $settings_model[ $new_key ] ?? null;
+		}
+	}
+
+	/**
+	 * Retrieves the mapped mismatch_behavior value from the new settings.
+	 *
+	 * @param array<string, scalar|array> $settings_model The new settings model data as an array.
+	 * @return 'extra_line'|'ditch'|null The mapped mismatch_behavior value.
+	 */
+	protected function mapped_mismatch_behavior_value( array $settings_model ): ?string {
+		$subtotal_adjustment = $settings_model[ 'subtotal_adjustment' ] ?? false;
+
+		if ( ! $subtotal_adjustment ) {
+			return null;
+		}
+
+		return $subtotal_adjustment === 'correction' ? PurchaseUnitSanitizer::MODE_EXTRA_LINE : PurchaseUnitSanitizer::MODE_DITCH;
+	}
+}