fix: address validation

app/src/main/java/to/bitkit/models/Network.kt

@@ -24,3 +24,10 @@ fun Network.toCoreNetworkType(): NetworkType = when (this) {
     Network.SIGNET -> NetworkType.SIGNET
     Network.REGTEST -> NetworkType.REGTEST
 }
+
+fun NetworkType.toLdkNetwork(): Network = when (this) {
+    NetworkType.BITCOIN -> Network.BITCOIN
+    NetworkType.TESTNET -> Network.TESTNET
+    NetworkType.SIGNET -> Network.SIGNET
+    NetworkType.REGTEST -> Network.REGTEST
+}

app/src/main/java/to/bitkit/utils/Bip21Utils.kt

@@ -4,6 +4,22 @@ import to.bitkit.models.SATS_IN_BTC
 
 object Bip21Utils {
 
+    private const val BIP21_PREFIX = "bitcoin:"
+
+    /**
+     * Checks if a BIP21 URI is duplicated (contains multiple bitcoin: prefixes).
+     * Workaround for https://github.com/synonymdev/bitkit-core/issues/63
+     * @return true if the input contains duplicated BIP21 URIs, false otherwise
+     */
+    fun isDuplicatedBip21(input: String): Boolean {
+        val lowercased = input.lowercase()
+        val firstIndex = lowercased.indexOf(BIP21_PREFIX)
+        if (firstIndex == -1) return false
+
+        val secondIndex = lowercased.indexOf(BIP21_PREFIX, firstIndex + BIP21_PREFIX.length)
+        return secondIndex != -1
+    }
+
     fun buildBip21Url(
         bitcoinAddress: String,
         amountSats: ULong? = null,

app/src/main/java/to/bitkit/utils/NetworkValidationHelper.kt

@@ -0,0 +1,25 @@
+package to.bitkit.utils
+
+import org.lightningdevkit.ldknode.Network
+
+/**
+ * Helper for validating Bitcoin network compatibility of addresses and invoices
+ */
+object NetworkValidationHelper {
+    /**
+     * Check if an address/invoice network mismatches the current app network
+     * @param addressNetwork The network detected from the address/invoice
+     * @param currentNetwork The app's current network (typically Env.network)
+     * @return true if there's a mismatch (address won't work on current network)
+     */
+    fun isNetworkMismatch(addressNetwork: Network?, currentNetwork: Network): Boolean {
+        if (addressNetwork == null) return false
+
+        // Special case: regtest uses testnet prefixes (m, n, 2, tb1)
+        if (currentNetwork == Network.REGTEST && addressNetwork == Network.TESTNET) {
+            return false
+        }
+
+        return addressNetwork != currentNetwork
+    }
+}