server: Allow to derive a SipHashKey from a Blockhash

server/app/com/xsn/explorer/gcs/SipHashKey.scala

@@ -1,6 +1,7 @@
 package com.xsn.explorer.gcs
 
 import com.google.common.primitives.Longs
+import com.xsn.explorer.models.values.Blockhash
 
 /**
  * Represents a SipHash key using a 128-bit value, compatible with Guava.
@@ -8,7 +9,12 @@ import com.google.common.primitives.Longs
  * @param k0 the first half of the key
  * @param k1 the second half of the key
  */
-case class SipHashKey(k0: Long, k1: Long)
+case class SipHashKey(k0: Long, k1: Long) {
+
+  override def toString: String = {
+    s"SipHashKey(${java.lang.Long.toUnsignedString(k0)}, ${java.lang.Long.toUnsignedString(k1)})"
+  }
+}
 
 object SipHashKey {
 
@@ -29,4 +35,15 @@ object SipHashKey {
     val k1 = Longs.fromByteArray(key.drop(8).reverse.toArray)
     SipHashKey(k0, k1)
   }
+
+  def fromBtcutil(hash: Blockhash): SipHashKey = {
+    val bytes = hash
+        .string
+        .take(32)
+        .grouped(2)
+        .map { hex => Integer.parseInt(hex, 16).asInstanceOf[Byte] }
+        .toList
+
+    fromBtcutil(bytes)
+  }
 }

server/test/com/xsn/explorer/gcs/SipHashKeySpec.scala

@@ -1,5 +1,6 @@
 package com.xsn.explorer.gcs
 
+import com.xsn.explorer.models.values.Blockhash
 import org.scalatest.MustMatchers._
 import org.scalatest.WordSpec
 
@@ -15,5 +16,12 @@ class SipHashKeySpec extends WordSpec {
       key.k0 must be(4692295987881554252L)
       key.k1 must be(1534194084347808571l)
     }
+
+    "allow to use a blockhash" in {
+      val blockhash = Blockhash.from("00000b59875e80b0afc6c657bc5318d39e03532b7d97fb78a4c7bd55c4840c32").get
+      val expected = "SipHashKey(12718269283101769728, 15210999809835452079)"
+      val key = SipHashKey.fromBtcutil(blockhash)
+      key.toString must be(expected)
+    }
   }
 }