Add room v3+ event ID calculator

vona/globals/__init__.py

@@ -169,7 +169,10 @@ def make_auth_header(
 	return authorization_headers[0].decode("utf-8")
 
 
-def redact_event(event):
+def redact_event(
+	event: dict,
+	for_event_id: bool = False,
+):
 	# Returns a redacted event as per
 	# the algorithm for v1/v2 rooms.
 
@@ -181,7 +184,6 @@ def redact_event(event):
 		"state_key",
 		"content",
 		"hashes",
-		"signatures",
 		"depth",
 		"prev_events",
 		"prev_state",
@@ -191,6 +193,9 @@ def redact_event(event):
 		"membership",
 	]
 
+	if not for_event_id:
+		allowed_keys.append("signatures")
+
 	redacted_event = {k: v for k, v in event.items() if k in allowed_keys}
 
 	if "type" in redacted_event and "content" in redacted_event:
@@ -236,6 +241,26 @@ def hash_and_sign_event(event_object):
 	return event_object
 
 
+def make_ref_hash(
+	event: dict,
+	room_ver: int = 3,
+):
+	stripped = redact_event(event, True)
+	evt_bytes = canonical_json(stripped)
+
+	evt_hash = base64.b64encode(
+		hashlib.sha256(evt_bytes).digest()
+	).decode("utf-8").rstrip("=")
+
+	if room_ver > 3:
+		while "+" in evt_hash:
+			evt_hash = evt_hash.replace("+", "-")
+		while "/" in evt_hash:
+			evt_hash = evt_hash.replace("/", "_")
+
+	return "$" + evt_hash
+
+
 def room_version_from_id(room):
 	room_id_no_sigil = room.replace("!", "")
 
@@ -345,7 +370,7 @@ class http_client:
 		)
 
 
-def strip_state(l) -> dict:
+def strip_state(l) -> list:
 	if not isinstance(l, list):
 		return l