feat: added libphonenumber for phone number validation

Author: demolaf

auth/build.gradle.kts

@@ -106,6 +106,9 @@ dependencies {
     api(Config.Libs.Firebase.auth)
     api(Config.Libs.PlayServices.auth)
 
+    // Phone number validation
+    implementation(Config.Libs.Misc.libphonenumber)
+
     compileOnly(Config.Libs.Provider.facebook)
     implementation(Config.Libs.Androidx.legacySupportv4) // Needed to override deps
     implementation(Config.Libs.Androidx.cardView) // Needed to override Facebook

auth/src/main/java/com/firebase/ui/auth/compose/configuration/validators/PhoneNumberValidator.kt

@@ -0,0 +1,67 @@
+/*
+ * Copyright 2025 Google Inc. All Rights Reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
+ * in compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the
+ * License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
+ * express or implied. See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.firebase.ui.auth.compose.configuration.validators
+
+import com.firebase.ui.auth.compose.configuration.string_provider.AuthUIStringProvider
+import com.firebase.ui.auth.compose.data.CountryData
+import com.google.i18n.phonenumbers.NumberParseException
+import com.google.i18n.phonenumbers.PhoneNumberUtil
+
+internal class PhoneNumberValidator(
+    override val stringProvider: AuthUIStringProvider,
+    val selectedCountry: CountryData,
+) :
+    FieldValidator {
+    private var _validationStatus = FieldValidationStatus(hasError = false, errorMessage = null)
+    private val phoneNumberUtil = PhoneNumberUtil.getInstance()
+
+    override val hasError: Boolean
+        get() = _validationStatus.hasError
+
+    override val errorMessage: String
+        get() = _validationStatus.errorMessage ?: ""
+
+    override fun validate(value: String): Boolean {
+        if (value.isEmpty()) {
+            _validationStatus = FieldValidationStatus(
+                hasError = true,
+                errorMessage = stringProvider.missingPhoneNumber
+            )
+            return false
+        }
+
+        try {
+            val phoneNumber = phoneNumberUtil.parse(value, selectedCountry.countryCode)
+            val isValid = phoneNumberUtil.isValidNumber(phoneNumber)
+
+            if (!isValid) {
+                _validationStatus = FieldValidationStatus(
+                    hasError = true,
+                    errorMessage = stringProvider.invalidPhoneNumber
+                )
+                return false
+            }
+        } catch (_: NumberParseException) {
+            _validationStatus = FieldValidationStatus(
+                hasError = true,
+                errorMessage = stringProvider.invalidPhoneNumber
+            )
+            return false
+        }
+
+        _validationStatus = FieldValidationStatus(hasError = false, errorMessage = null)
+        return true
+    }
+}

buildSrc/src/main/kotlin/Config.kt

@@ -83,6 +83,7 @@ object Config {
             const val glideCompiler = "com.github.bumptech.glide:compiler:$glideVersion"
 
             const val permissions = "pub.devrel:easypermissions:3.0.0"
+            const val libphonenumber = "com.googlecode.libphonenumber:libphonenumber:9.0.16"
         }
 
         object Test {