From 6e595a0959224553f4d0133512031390dc4d585c Mon Sep 17 00:00:00 2001
From: Ravi Khadiwala <ravi@signal.org>
Date: Mon, 26 Sep 2022 10:26:13 -0500
Subject: [PATCH] add an optionals utility and fix push challenge metric

---
 .../controllers/AccountController.java        | 15 ++++++-------
 .../textsecuregcm/util/Optionals.java         | 21 +++++++++++++++++++
 2 files changed, 29 insertions(+), 7 deletions(-)
 create mode 100644 service/src/main/java/org/whispersystems/textsecuregcm/util/Optionals.java

diff --git a/service/src/main/java/org/whispersystems/textsecuregcm/controllers/AccountController.java b/service/src/main/java/org/whispersystems/textsecuregcm/controllers/AccountController.java
index 5185d6610..d5c219081 100644
--- a/service/src/main/java/org/whispersystems/textsecuregcm/controllers/AccountController.java
+++ b/service/src/main/java/org/whispersystems/textsecuregcm/controllers/AccountController.java
@@ -102,6 +102,7 @@ import org.whispersystems.textsecuregcm.util.ForwardedIpUtil;
 import org.whispersystems.textsecuregcm.util.Hex;
 import org.whispersystems.textsecuregcm.util.ImpossiblePhoneNumberException;
 import org.whispersystems.textsecuregcm.util.NonNormalizedPhoneNumberException;
+import org.whispersystems.textsecuregcm.util.Optionals;
 import org.whispersystems.textsecuregcm.util.UsernameGenerator;
 import org.whispersystems.textsecuregcm.util.Util;
 import org.whispersystems.textsecuregcm.util.VerificationCode;
@@ -832,14 +833,14 @@ public class AccountController {
       final Optional<StoredVerificationCode> storedVerificationCode) {
     final String countryCode = Util.getCountryCode(number);
     final String region = Util.getRegion(number);
-
-    final List<Tag> tags = new ArrayList<>();
-    tags.add(Tag.of(COUNTRY_CODE_TAG_NAME, countryCode));
-    tags.add(Tag.of(REGION_TAG_NAME, region));
-    tags.add(Tag.of(CHALLENGE_PRESENT_TAG_NAME, Boolean.toString(pushChallenge.isPresent())));
     Optional<String> storedPushChallenge = storedVerificationCode.map(StoredVerificationCode::getPushCode);
-    boolean match = pushChallenge.isPresent() && storedPushChallenge.isPresent() && pushChallenge.get().equals(storedPushChallenge.get());
-    tags.add(Tag.of(CHALLENGE_MATCH_TAG_NAME, Boolean.toString(match)));
+    boolean match = Optionals.zipWith(pushChallenge, storedPushChallenge, String::equals).orElse(false);
+    Metrics.counter(PUSH_CHALLENGE_COUNTER_NAME,
+            COUNTRY_CODE_TAG_NAME, countryCode,
+            REGION_TAG_NAME, region,
+            CHALLENGE_PRESENT_TAG_NAME, Boolean.toString(pushChallenge.isPresent()),
+            CHALLENGE_MATCH_TAG_NAME, Boolean.toString(match))
+        .increment();
     return match;
   }
 
diff --git a/service/src/main/java/org/whispersystems/textsecuregcm/util/Optionals.java b/service/src/main/java/org/whispersystems/textsecuregcm/util/Optionals.java
new file mode 100644
index 000000000..4e3e49038
--- /dev/null
+++ b/service/src/main/java/org/whispersystems/textsecuregcm/util/Optionals.java
@@ -0,0 +1,21 @@
+package org.whispersystems.textsecuregcm.util;
+
+import java.util.Optional;
+import java.util.function.BiFunction;
+
+public class Optionals {
+
+  private Optionals() {}
+
+  /**
+   * Apply a function to two optional arguments, returning empty if either argument is empty
+   *
+   * @param optionalT Optional of type T
+   * @param optionalU Optional of type U
+   * @param fun       Function of T and U that returns R
+   * @return The function applied to the values of optionalT and optionalU, or empty
+   */
+  public static <T, U, R> Optional<R> zipWith(Optional<T> optionalT, Optional<U> optionalU, BiFunction<T, U, R> fun) {
+    return optionalT.flatMap(t -> optionalU.map(u -> fun.apply(t, u)));
+  }
+}