From 63b8363da9886677cc529d37c251e6d4f1ccaa54 Mon Sep 17 00:00:00 2001
From: mikeplotean <mike@walt.id>
Date: Tue, 14 Jan 2025 17:20:42 +0200
Subject: [PATCH] refactor: revocation policy

---
 .../policies/policies/RevocationPolicy.jvm.kt | 50 +++++++++++--------
 1 file changed, 28 insertions(+), 22 deletions(-)

diff --git a/waltid-libraries/credentials/waltid-verification-policies/src/jvmMain/kotlin/id/walt/policies/policies/RevocationPolicy.jvm.kt b/waltid-libraries/credentials/waltid-verification-policies/src/jvmMain/kotlin/id/walt/policies/policies/RevocationPolicy.jvm.kt
index 8e59be4535..c333c4880c 100644
--- a/waltid-libraries/credentials/waltid-verification-policies/src/jvmMain/kotlin/id/walt/policies/policies/RevocationPolicy.jvm.kt
+++ b/waltid-libraries/credentials/waltid-verification-policies/src/jvmMain/kotlin/id/walt/policies/policies/RevocationPolicy.jvm.kt
@@ -33,31 +33,37 @@ actual class RevocationPolicy : RevocationPolicyMp() {
             }
         }
 
-        val response = runCatching { httpClient.get(statusListCredentialUrl!!).bodyAsText() }
-
-        if (response.isFailure) {
+        val response = runCatching { httpClient.get(statusListCredentialUrl!!).bodyAsText() }.getOrElse {
             return Result.failure(Throwable("Error when getting Status List Credential from  $statusListCredentialUrl"))
         }
-
-        return try {
-            // response is a jwt
-            val payload = response.getOrThrow().substringAfter(".").substringBefore(".")
-                .let { Json.decodeFromString<JsonObject>(Base64Utils.decode(it).decodeToString()) }
-
-            val credentialSubject = payload["vc"]!!.jsonObject["credentialSubject"]?.jsonObject!!
-            val encodedList = credentialSubject["encodedList"]?.jsonPrimitive?.content ?: ""
-            val bitValue = get(encodedList, statusListIndex)
-            // ensure bitValue always consists of valid binary characters (0,1)
-            require(!bitValue.isNullOrEmpty()) { "Null or empty bit value" }
-            require(isBinaryValue(bitValue)) { "Invalid bit value" }
-            if (StreamUtils.binToInt(bitValue.joinToString("")) == 0) {
-                Result.success(statusListCredentialUrl!!)
-            } else {
-                Result.failure(Throwable("Credential has been revoked"))
-            }
-        } catch (e: NumberFormatException) {
-            throw IllegalArgumentException()
+        // response is a jwt
+        val bitValue = getRevocationStatusValue(response, statusListIndex).getOrElse {
+            return Result.failure(Throwable(it.cause))
+        }
+        checkStatus(bitValue).getOrElse {
+            return Result.failure(Throwable("Credential has been revoked"))
         }
+        return Result.success(statusListCredentialUrl!!)
+    }
+
+    private fun checkStatus(it: List<Char>) = runCatching {
+        require(StreamUtils.binToInt(it.joinToString("")) == 0)
+    }
+
+    private fun getRevocationStatusValue(
+        response: String,
+        statusListIndex: ULong?
+    ) = runCatching {
+        val payload = response.substringAfter(".").substringBefore(".")
+            .let { Json.decodeFromString<JsonObject>(Base64Utils.decode(it).decodeToString()) }
+
+        val credentialSubject = payload["vc"]!!.jsonObject["credentialSubject"]?.jsonObject!!
+        val encodedList = credentialSubject["encodedList"]?.jsonPrimitive?.content ?: ""
+        val bitValue = get(encodedList, statusListIndex)
+        // ensure bitValue always consists of valid binary characters (0,1)
+        require(!bitValue.isNullOrEmpty()) { "Null or empty bit value" }
+        require(isBinaryValue(bitValue)) { "Invalid bit value: $bitValue" }
+        bitValue
     }
 
 }