[Paywalls] Add default locale (#1809)

### Motivation

Support new `default_locale` property in paywall data

### Description

If localization for preferred language isn't found, use the default
locale before falling back to the first locale.

#### Demo



https://github.com/user-attachments/assets/fae5bfb1-d22b-4d69-a944-ff3311c47ee5

---------

Co-authored-by: Toni Rico <toni.rico.diez@revenuecat.com>

examples/paywall-tester/src/main/java/com/revenuecat/paywallstester/Constants.kt

@@ -1,5 +1,5 @@
 package com.revenuecat.paywallstester
 
 object Constants {
- const val GOOGLE_API_KEY = "goog_uArAGtKQJeuXMWoSNXCAZBzTepD"
+ const val GOOGLE_API_KEY = "API_KEY"
 }

purchases/src/main/kotlin/com/revenuecat/purchases/paywalls/PaywallData.kt

@@ -49,6 +49,11 @@ data class PaywallData(
  @SerialName("zero_decimal_place_countries")
  @Serializable(with = GoogleListSerializer::class)
  val zeroDecimalPlaceCountries: List<String> = emptyList(),
+
+ /**
+ * The default locale to be used on a paywall if the preferred languages aren't found.
+ */
+ @SerialName("default_locale") val defaultLocale: String? = null,
 ) {
 
  /**
@@ -61,6 +66,7 @@ data class PaywallData(
  }
 
  @VisibleForTesting
+ @Suppress("ReturnCount")
  fun localizedConfiguration(locales: List<Locale>): Pair<Locale, LocalizedConfiguration> {
  for (locale in locales) {
  val localeToCheck = locale.convertToCorrectlyFormattedLocale()
@@ -69,6 +75,15 @@ data class PaywallData(
  }
  }
 
+ // Try finding default local
+ defaultLocale?.let { defaultLocale ->
+ localization.entries.firstOrNull { localization ->
+ localization.key.toLocale() == defaultLocale.toLocale()
+ }?.let { localization ->
+ return (localization.key.toLocale() to localization.value)
+ }
+ }
+
  // Fallback to first localization
  localization.entries.first().let { localization ->
  return (localization.key.toLocale() to localization.value)
@@ -92,6 +107,7 @@ data class PaywallData(
  return tieredConfigForLocales(locales = getDefaultLocales())
  }
 
+ @Suppress("ReturnCount")
  private fun tieredConfigForLocales(locales: List<Locale>): Pair<Locale, Map<String, LocalizedConfiguration>> {
  for (locale in locales) {
  val localeToCheck = locale.convertToCorrectlyFormattedLocale()
@@ -100,9 +116,18 @@ data class PaywallData(
  }
  }
 
+ // Try finding default locale
+ defaultLocale?.let { defaultLocale ->
+ localizationByTier.entries.firstOrNull { localization ->
+ localization.key.toLocale() == defaultLocale.toLocale()
+ }?.let { localization ->
+ return (localization.key.toLocale() to localization.value)
+ }
+ }
+
  // Fallback to first localization
  val first = localizationByTier.entries.first()
- return Pair(first.key.toLocale(), first.value)
+ return (first.key.toLocale() to first.value)
  }
 
  @VisibleForTesting

purchases/src/test/java/com/revenuecat/purchases/paywalls/PaywallDataTest.kt

@@ -16,6 +16,7 @@ import java.util.*
 private const val PAYWALLDATA_SAMPLE1 = "paywalldata-sample1.json"
 private const val PAYWALLDATA_CHINESE = "paywalldata-chinese.json"
 private const val PAYWALLDATA_MISSING_CURRENT_LOCALE = "paywalldata-missing_current_locale.json"
+private const val PAYWALLDATA_DEFAULT_LOCALE_WITH_MISSING_CURRENT_LOCALE = "paywalldata-default-locale-with-missing_current_locale.json"
 private const val PAYWALLDATA_EMPTY_IMAGES = "paywalldata-empty-images.json"
 
 @RunWith(AndroidJUnit4::class)
@@ -149,6 +150,15 @@ class PaywallDataTest {
  assertThat(localization.title).isEqualTo("Tienda")
  }
 
+ @Test
+ fun `if current locale is missing it loads default locale`() {
+ val paywall: PaywallData = decode(PAYWALLDATA_DEFAULT_LOCALE_WITH_MISSING_CURRENT_LOCALE)
+
+ val localization = paywall.localizedConfiguration.second
+ assertThat(localization.callToAction).isEqualTo("Kup")
+ assertThat(localization.title).isEqualTo("Sklep")
+ }
+
  @Test
  fun `localized configuration finds locale with different region`() {
  val paywall: PaywallData = decode(PAYWALLDATA_SAMPLE1)

purchases/src/test/resources/paywalldata-default-locale-with-missing_current_locale.json

@@ -0,0 +1,37 @@
+{
+ "template_name": "1",
+ "localized_strings": {
+ "es_ES": {
+ "title": "Tienda",
+ "subtitle": "Descripción",
+ "call_to_action": "Comprar",
+ "call_to_action_with_intro_offer": "Comprar",
+ "offer_details": "{{ sub_price_per_month }} cada mes",
+ "offer_details_with_intro_offer": "Comienza tu prueba de {{ sub_offer_duration }}, y después {{ sub_price_per_month }} cada mes"
+ },
+ "pl_PL": {
+ "title": "Sklep",
+ "subtitle": "Opis",
+ "call_to_action": "Kup",
+ "call_to_action_with_intro_offer": "Kup",
+ "offer_details": "{{ sub_price_per_month }} co miesiąc",
+ "offer_details_with_intro_offer": "Rozpocznij swój {{ sub_offer_duration }} okres próbny, a następnie {{ sub_price_per_month }} co miesiąc"
+ }
+ },
+ "config": {
+ "packages": ["$rc_monthly", "$rc_annual"],
+ "images_webp": {},
+ "colors": {
+ "light": {
+ "background": "#FFFFFF",
+ "text_1": "#FFFFFF",
+ "call_to_action_background": "#FFFFFF",
+ "call_to_action_foreground": "#FFFFFF",
+ "accent_1": "#FFFFFF"
+ },
+ "dark": null
+ }
+ },
+ "asset_base_url": "https://rc-paywalls.s3.amazonaws.com",
+ "default_locale": "pl_PL"
+}