feat: create invoice to join

helpers.py

@@ -0,0 +1,19 @@
+from bech32 import bech32_decode, convertbits
+
+
+def normalize_public_key(pubkey: str) -> str:
+    if pubkey.startswith('npub1'):
+        _, decoded_data = bech32_decode(pubkey)
+        if not decoded_data:
+            raise ValueError("Public Key is not valid npub")
+
+        decoded_data_bits = convertbits(decoded_data, 5, 8, False)
+        if not  decoded_data_bits:
+            raise ValueError("Public Key is not valid npub")
+        return bytes(decoded_data_bits).hex()
+    
+    #check if valid hex
+    if len(pubkey) != 64:
+        raise ValueError("Public Key is not valid hex")
+    int(pubkey, 16)
+    return pubkey