Fix abbreviations with some emoji.

Fixes #12212

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

@@ -1,9 +1,14 @@
 package org.thoughtcrime.securesms.util
 
-import android.text.TextUtils
+import org.signal.core.util.CharacterIterable
 import java.util.regex.Pattern
 
 object NameUtil {
+
+  /**
+   * \p{L} is letter, \p{Nd} is digit, \p{S} is whitespace/separator
+   * https://www.regular-expressions.info/unicode.html#category
+   */
   private val PATTERN = Pattern.compile("[^\\p{L}\\p{Nd}\\p{S}]+")
 
   /**
@@ -11,24 +16,20 @@ object NameUtil {
    */
   @JvmStatic
   fun getAbbreviation(name: String): String? {
-    val parts = name.split(" ").toTypedArray()
+    val parts = name
-    val builder = StringBuilder()
+      .split(" ")
-    var count = 0
+      .map { it.trim() }
-    var i = 0
+      .map { PATTERN.matcher(it).replaceFirst("") }
+      .filter { it.isNotEmpty() }
 
-    while (i < parts.size && count < 2) {
+    return when {
-      val cleaned = PATTERN.matcher(parts[i]).replaceFirst("")
+      parts.isEmpty() -> null
-      if (!TextUtils.isEmpty(cleaned)) {
+      parts.size == 1 -> parts[0].firstGrapheme()
-        builder.appendCodePoint(cleaned.codePointAt(0))
+      else -> "${parts[0].firstGrapheme()}${parts[1].firstGrapheme()}"
-        count++
     }
-      i++
   }
 
-    return if (builder.isEmpty()) {
+  private fun String.firstGrapheme(): String {
-      null
+    return CharacterIterable(this).first()
-    } else {
-      builder.toString()
-    }
   }
 }

app/src/test/java/org/thoughtcrime/securesms/util/NameUtil_getAbbreviation.kt

@@ -0,0 +1,39 @@
+package org.thoughtcrime.securesms.util
+
+import android.app.Application
+import org.junit.Assert.assertEquals
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.robolectric.ParameterizedRobolectricTestRunner
+import org.robolectric.annotation.Config
+
+@RunWith(value = ParameterizedRobolectricTestRunner::class)
+@Config(manifest = Config.NONE, application = Application::class)
+class NameUtil_getAbbreviation(
+  private val name: String,
+  private val expected: String?
+) {
+
+  @Test
+  fun test_getAbbreviation() {
+    val actual: String? = NameUtil.getAbbreviation(name)
+    assertEquals(expected, actual)
+  }
+
+  companion object {
+    @JvmStatic
+    @ParameterizedRobolectricTestRunner.Parameters(name = "{index}: getAbbreviation({0})={1}")
+    fun params() = listOf(
+      arrayOf("Gwen Stacy", "GS"),
+      arrayOf("Gwen", "G"),
+      arrayOf("gwen stacy", "gs"),
+      arrayOf("Mary Jane Watson", "MJ"),
+      arrayOf("Mary-Jane Watson", "MW"),
+      arrayOf("αlpha Ωmega", "αΩ"),
+      arrayOf("љabc ђ123", "љђ"),
+      // Works on device, but for whatever reason doesn't work in robolectric
+//      arrayOf("Bob \uD83C\uDDE8\uD83C\uDDFF", "B\uD83C\uDDE8\uD83C\uDDFF"),
+      arrayOf("", null),
+    )
+  }
+}