Merge pull request #58 from capcom6/issue/52-local-ip-tethering

Try to get local IP from iface in tethering mode

app/src/main/java/me/capcom/smsgateway/providers/LocalIPProvider.kt

@@ -1,29 +1,54 @@
 package me.capcom.smsgateway.providers
 
 import android.content.Context
-import android.content.Context.WIFI_SERVICE
 import android.net.wifi.WifiManager
-import java.math.BigInteger
-import java.net.InetAddress
-import java.nio.ByteOrder
+import java.net.Inet4Address
+import java.net.NetworkInterface
 
 
 class LocalIPProvider(private val context: Context): IPProvider {
     override suspend fun getIP(): String? {
-        return try {
-            var ipAddress =
-                (context.applicationContext.getSystemService(WIFI_SERVICE) as WifiManager).connectionInfo.ipAddress
-            // Convert little-endian to big-endianif needed
-            if (ByteOrder.nativeOrder().equals(ByteOrder.LITTLE_ENDIAN)) {
-                ipAddress = Integer.reverseBytes(ipAddress)
+        try {
+            val wifiManager =
+                context.applicationContext.getSystemService(Context.WIFI_SERVICE) as WifiManager
+
+            // If the device is in tethering mode, the following method may return null or a default IP
+            wifiManager.connectionInfo?.let { connectionInfo ->
+                val ipInt = connectionInfo.ipAddress
+                if (ipInt != 0) {
+                    return (ipInt and 0xFF).toString() + "." +
+                            ((ipInt shr 8) and 0xFF) + "." +
+                            ((ipInt shr 16) and 0xFF) + "." +
+                            ((ipInt shr 24) and 0xFF)
+                }
             }
 
-            val ipByteArray: ByteArray = BigInteger.valueOf(0L + ipAddress).toByteArray()
+            // If the above doesn't work, try to find the WiFi network interface directly
+            val wifiInterface = NetworkInterface.getNetworkInterfaces().asSequence()
+                .find { it.name.contains("wlan", ignoreCase = true) }
+
+            wifiInterface?.inetAddresses?.asSequence()
+                ?.find { !it.isLoopbackAddress && it is Inet4Address }
+                ?.let { inetAddress ->
+                    return inetAddress.hostAddress
+                }
 
-            (InetAddress.getByAddress(ipByteArray).hostAddress)
+            // Check any other network interface
+            val interfaces = NetworkInterface.getNetworkInterfaces()
+            while (interfaces.hasMoreElements()) {
+                val intf = interfaces.nextElement()
+                val addrs = intf.inetAddresses
+                while (addrs.hasMoreElements()) {
+                    val addr = addrs.nextElement()
+                    if (!addr.isLoopbackAddress && addr is Inet4Address) {
+                        return addr.hostAddress
+                    }
+                }
+            }
         } catch (e: Exception) {
             e.printStackTrace()
-            null
         }
+
+        return null
     }
 }