Add defaults for script/text font pairings and guessing of script based on body contents.

Co-authored-by: Alex Hart <alex@signal.org>

app/src/main/java/org/thoughtcrime/securesms/util/LocaleUtil.kt

@@ -0,0 +1,33 @@
+package org.thoughtcrime.securesms.util
+
+import androidx.core.os.LocaleListCompat
+import org.thoughtcrime.securesms.keyvalue.SignalStore
+import org.thoughtcrime.securesms.util.dynamiclanguage.LanguageString
+import java.util.Locale
+
+object LocaleUtil {
+
+  fun getFirstLocale(): Locale {
+    return getLocaleDefaults().firstOrNull() ?: Locale.getDefault()
+  }
+
+  /**
+   * Get a user priority list of locales supported on the device, with the locale set via Signal settings
+   * as highest priority over system settings.
+   */
+  fun getLocaleDefaults(): List<Locale> {
+    val locales: MutableList<Locale> = mutableListOf()
+    val signalLocale: Locale? = LanguageString.parseLocale(SignalStore.settings().language)
+    val localeList: LocaleListCompat = LocaleListCompat.getDefault()
+
+    if (signalLocale != null) {
+      locales += signalLocale
+    }
+
+    for (index in 0 until localeList.size()) {
+      locales += localeList.get(index)
+    }
+
+    return locales
+  }
+}