From b6e463714c6fd729c8f91a77b27a83128f097967 Mon Sep 17 00:00:00 2001
From: Konrad Feldmeier <konrad@brainbot.com>
Date: Thu, 16 Jan 2025 14:46:50 +0100
Subject: [PATCH] Experimental: add ComputeEpochID to WASM

---
 .../shcryptowasm/shutter_crypto_wasm.go          | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/rolling-shutter/shcryptowasm/shutter_crypto_wasm.go b/rolling-shutter/shcryptowasm/shutter_crypto_wasm.go
index d197ae0ff..e331b95b2 100644
--- a/rolling-shutter/shcryptowasm/shutter_crypto_wasm.go
+++ b/rolling-shutter/shcryptowasm/shutter_crypto_wasm.go
@@ -27,6 +27,7 @@ func main() {
 
 	jsRegistry.Set("encrypt", encrypt)
 	jsRegistry.Set("decrypt", decrypt)
+	jsRegistry.Set("computeEpochID", computeEpochID)
 	jsRegistry.Set("verifyDecryptionKey", verifyDecryptionKey)
 
 	// Tell JS we're loaded
@@ -116,6 +117,21 @@ var verifyDecryptionKey = js.FuncOf(func(this js.Value, args []js.Value) interfa
 	return ok
 })
 
+var computeEpochID = js.FuncOf(func(this js.Value, args []js.Value) interface{} {
+    if len(args) != 1 {
+        return encodeResult(nil, fmt.Errorf("expected 1 argument, got %d", len(args)))
+    }
+    b, err := decodeBytesArg(args[0], "epochIDBytes")
+    if err != nil {
+        return encodeResult(nil, err)
+    }
+    e, err := shcrypto.ComputeEpochID(b)
+    if err != nil {
+        return encodeResult(nil, err)
+    }
+    return encodeResult(e, nil)
+}
+
 func encodeResult(encryptedMessage []byte, err error) string {
 	if err != nil {
 		return "Error: " + err.Error()