feat: PhoneAuthScreen, enter phone number and verification code

Author: demolaf

auth/src/main/java/com/firebase/ui/auth/compose/configuration/string_provider/AuthUIStringProvider.kt

@@ -159,6 +159,9 @@ interface AuthUIStringProvider {
     /** Invalid phone number error */
     val invalidPhoneNumber: String
 
+    /** Missing phone number error */
+    val missingPhoneNumber: String
+
     /** Phone verification code entry form title */
     val enterConfirmationCode: String
 
@@ -171,6 +174,9 @@ interface AuthUIStringProvider {
     /** Resend code link text */
     val resendCode: String
 
+    /** Resend code with timer */
+    fun resendCodeTimer(seconds: Int): String
+
     /** Verifying progress text */
     val verifying: String
 
@@ -180,6 +186,42 @@ interface AuthUIStringProvider {
     /** SMS terms of service warning */
     val smsTermsOfService: String
 
+    /** Enter phone number title */
+    val enterPhoneNumberTitle: String
+
+    /** Phone number hint */
+    val phoneNumberHint: String
+
+    /** Send verification code button text */
+    val sendVerificationCode: String
+
+    /** Enter verification code title with phone number */
+    fun enterVerificationCodeTitle(phoneNumber: String): String
+
+    /** Verification code hint */
+    val verificationCodeHint: String
+
+    /** Verify code button text */
+    val verifyCode: String
+
+    /** Change phone number link text */
+    val changePhoneNumber: String
+
+    /** Missing verification code error */
+    val missingVerificationCode: String
+
+    /** Invalid verification code error */
+    val invalidVerificationCode: String
+
+    /** Country code label */
+    val countryCode: String
+
+    /** Select country dialog title */
+    val selectCountry: String
+
+    /** Search countries hint */
+    val searchCountries: String
+
     // Provider Picker Strings
     /** Common button text for sign in */
     val signInDefault: String

auth/src/main/java/com/firebase/ui/auth/compose/configuration/string_provider/DefaultAuthUIStringProvider.kt

@@ -159,6 +159,8 @@ class DefaultAuthUIStringProvider(
         get() = localizedContext.getString(R.string.fui_country_hint)
     override val invalidPhoneNumber: String
         get() = localizedContext.getString(R.string.fui_invalid_phone_number)
+    override val missingPhoneNumber: String
+        get() = localizedContext.getString(R.string.fui_required_field)
     override val enterConfirmationCode: String
         get() = localizedContext.getString(R.string.fui_enter_confirmation_code)
     override val verifyPhoneNumber: String
@@ -167,13 +169,53 @@ class DefaultAuthUIStringProvider(
         get() = localizedContext.getString(R.string.fui_resend_code_in)
     override val resendCode: String
         get() = localizedContext.getString(R.string.fui_resend_code)
+
+    override fun resendCodeTimer(seconds: Int): String =
+        localizedContext.getString(R.string.fui_resend_code_in, seconds)
+
     override val verifying: String
         get() = localizedContext.getString(R.string.fui_verifying)
     override val incorrectCodeDialogBody: String
         get() = localizedContext.getString(R.string.fui_incorrect_code_dialog_body)
     override val smsTermsOfService: String
         get() = localizedContext.getString(R.string.fui_sms_terms_of_service)
 
+    override val enterPhoneNumberTitle: String
+        get() = localizedContext.getString(R.string.fui_verify_phone_number_title)
+
+    override val phoneNumberHint: String
+        get() = localizedContext.getString(R.string.fui_phone_hint)
+
+    override val sendVerificationCode: String
+        get() = localizedContext.getString(R.string.fui_next_default)
+
+    override fun enterVerificationCodeTitle(phoneNumber: String): String =
+        localizedContext.getString(R.string.fui_enter_confirmation_code) + " " + phoneNumber
+
+    override val verificationCodeHint: String
+        get() = localizedContext.getString(R.string.fui_enter_confirmation_code)
+
+    override val verifyCode: String
+        get() = localizedContext.getString(R.string.fui_verify_phone_number)
+
+    override val changePhoneNumber: String
+        get() = localizedContext.getString(R.string.fui_change_phone_number)
+
+    override val missingVerificationCode: String
+        get() = localizedContext.getString(R.string.fui_required_field)
+
+    override val invalidVerificationCode: String
+        get() = localizedContext.getString(R.string.fui_incorrect_code_dialog_body)
+
+    override val countryCode: String
+        get() = localizedContext.getString(R.string.fui_country_hint)
+
+    override val selectCountry: String
+        get() = localizedContext.getString(R.string.fui_country_hint)
+
+    override val searchCountries: String
+        get() = localizedContext.getString(R.string.fui_country_hint)
+
     /**
      * Multi-Factor Authentication Strings
      */

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

@@ -0,0 +1,51 @@
+/*
+ * 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
+
+internal class VerificationCodeValidator(override val stringProvider: AuthUIStringProvider) :
+    FieldValidator {
+    private var _validationStatus = FieldValidationStatus(hasError = false, errorMessage = null)
+
+    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.missingVerificationCode
+            )
+            return false
+        }
+
+        // Verification codes are typically 6 digits
+        val digitsOnly = value.replace(Regex("[^0-9]"), "")
+        if (digitsOnly.length != 6) {
+            _validationStatus = FieldValidationStatus(
+                hasError = true,
+                errorMessage = stringProvider.invalidVerificationCode
+            )
+            return false
+        }
+
+        _validationStatus = FieldValidationStatus(hasError = false, errorMessage = null)
+        return true
+    }
+}

auth/src/main/java/com/firebase/ui/auth/compose/data/CountryUtils.kt

@@ -68,6 +68,44 @@ object CountryUtils {
         }
     }
 
+    /**
+     * Searches for countries by name, country code, or dial code.
+     * Supports partial matching and diacritic-insensitive search.
+     *
+     * @param query The search query (country name, country code, or dial code).
+     * @return List of countries matching the query, sorted by relevance.
+     */
+    fun search(query: String): List<CountryData> {
+        val trimmedQuery = query.trim()
+        if (trimmedQuery.isEmpty()) return emptyList()
+
+        val normalizedQuery = normalizeString(trimmedQuery)
+        val uppercaseQuery = trimmedQuery.uppercase()
+
+        return ALL_COUNTRIES.filter { country ->
+            // Match by country name (partial, case-insensitive, diacritic-insensitive)
+            normalizeString(country.name).contains(normalizedQuery, ignoreCase = true) ||
+            // Match by country code (partial, case-insensitive)
+            country.countryCode.uppercase().contains(uppercaseQuery) ||
+            // Match by dial code (partial)
+            country.dialCode.contains(trimmedQuery)
+        }.sortedWith(
+            compareBy(
+                // Prioritize exact matches first
+                { country ->
+                    when {
+                        country.countryCode.uppercase() == uppercaseQuery -> 0
+                        country.dialCode == trimmedQuery -> 1
+                        normalizeString(country.name) == normalizedQuery -> 2
+                        else -> 3
+                    }
+                },
+                // Then sort alphabetically by name
+                { country -> country.name }
+            )
+        )
+    }
+
     /**
      * Filters countries by allowed country codes.
      *

auth/src/main/java/com/firebase/ui/auth/compose/ui/components/AuthTextField.kt

@@ -130,7 +130,7 @@ fun AuthTextField(
                 {
                     Icon(
                         imageVector = Icons.Default.Email,
-                        contentDescription = ""
+                        contentDescription = "Email Input Icon"
                     )
                 }
             }
@@ -139,7 +139,7 @@ fun AuthTextField(
                 {
                     Icon(
                         imageVector = Icons.Default.Lock,
-                        contentDescription = ""
+                        contentDescription = "Password Input Icon"
                     )
                 }
             }