feat(android): show proxy traffic stats in foreground notification

android/app/src/main/java/org/flowseal/tgwsproxy/ProxyForegroundService.kt

@@ -13,13 +13,19 @@ import androidx.core.app.TaskStackBuilder
 import androidx.core.app.NotificationCompat
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.Job
 import kotlinx.coroutines.SupervisorJob
 import kotlinx.coroutines.cancel
+import kotlinx.coroutines.delay
+import kotlinx.coroutines.isActive
 import kotlinx.coroutines.launch
+import java.util.Locale
 
 class ProxyForegroundService : Service() {
     private lateinit var settingsStore: ProxySettingsStore
     private val serviceScope = CoroutineScope(SupervisorJob() + Dispatchers.IO)
+    private var trafficJob: Job? = null
+    private var lastTrafficSample: TrafficSample? = null
 
     override fun onCreate() {
         super.onCreate()
@@ -69,6 +75,7 @@ class ProxyForegroundService : Service() {
     }
 
     override fun onDestroy() {
+        stopTrafficUpdates()
         serviceScope.cancel()
         runCatching { PythonProxyBridge.stop(this) }
         ProxyServiceState.markStopped()
@@ -104,6 +111,7 @@ class ProxyForegroundService : Service() {
 
         result.onSuccess {
             ProxyServiceState.markStarted(config)
+            lastTrafficSample = null
             updateNotification(
                 buildNotificationPayload(
                     config = config,
@@ -114,16 +122,19 @@ class ProxyForegroundService : Service() {
                     ),
                 ),
             )
+            startTrafficUpdates(config)
         }.onFailure { error ->
             ProxyServiceState.markFailed(
                 error.message ?: getString(R.string.proxy_start_failed_generic),
             )
+            stopTrafficUpdates()
             stopForeground(STOP_FOREGROUND_REMOVE)
             stopSelf()
         }
     }
 
     private fun stopProxyRuntime(removeNotification: Boolean, stopService: Boolean) {
+        stopTrafficUpdates()
         runCatching { PythonProxyBridge.stop(this) }
         ProxyServiceState.markStopped()
 
@@ -144,17 +155,15 @@ class ProxyForegroundService : Service() {
         config: NormalizedProxyConfig,
         statusText: String,
     ): NotificationPayload {
+        val trafficState = readTrafficState()
         val endpointText = getString(R.string.notification_endpoint, config.host, config.port)
         val detailsText = getString(
             R.string.notification_details,
-            config.host,
-            config.port,
             config.dcIpList.size,
-            if (config.verbose) {
-                getString(R.string.notification_verbose_on)
-            } else {
-                getString(R.string.notification_verbose_off)
-            },
+            formatRate(trafficState.upBytesPerSecond),
+            formatRate(trafficState.downBytesPerSecond),
+            formatBytes(trafficState.totalBytesUp),
+            formatBytes(trafficState.totalBytesDown),
         )
         return NotificationPayload(
             statusText = statusText,
@@ -163,6 +172,80 @@ class ProxyForegroundService : Service() {
         )
     }
 
+    private fun startTrafficUpdates(config: NormalizedProxyConfig) {
+        stopTrafficUpdates()
+        trafficJob = serviceScope.launch {
+            while (isActive && ProxyServiceState.isRunning.value) {
+                updateNotification(
+                    buildNotificationPayload(
+                        config = config,
+                        statusText = getString(
+                            R.string.notification_running,
+                            config.host,
+                            config.port,
+                        ),
+                    ),
+                )
+                delay(1000)
+            }
+        }
+    }
+
+    private fun stopTrafficUpdates() {
+        trafficJob?.cancel()
+        trafficJob = null
+        lastTrafficSample = null
+    }
+
+    private fun readTrafficState(): TrafficState {
+        val nowMillis = System.currentTimeMillis()
+        val current = PythonProxyBridge.getTrafficStats(this)
+        val previous = lastTrafficSample
+        lastTrafficSample = TrafficSample(
+            bytesUp = current.bytesUp,
+            bytesDown = current.bytesDown,
+            timestampMillis = nowMillis,
+        )
+
+        if (!current.running || previous == null) {
+            return TrafficState(
+                upBytesPerSecond = 0L,
+                downBytesPerSecond = 0L,
+                totalBytesUp = current.bytesUp,
+                totalBytesDown = current.bytesDown,
+            )
+        }
+
+        val elapsedMillis = (nowMillis - previous.timestampMillis).coerceAtLeast(1L)
+        val upDelta = (current.bytesUp - previous.bytesUp).coerceAtLeast(0L)
+        val downDelta = (current.bytesDown - previous.bytesDown).coerceAtLeast(0L)
+        return TrafficState(
+            upBytesPerSecond = (upDelta * 1000L) / elapsedMillis,
+            downBytesPerSecond = (downDelta * 1000L) / elapsedMillis,
+            totalBytesUp = current.bytesUp,
+            totalBytesDown = current.bytesDown,
+        )
+    }
+
+    private fun formatRate(bytesPerSecond: Long): String = formatBytes(bytesPerSecond)
+
+    private fun formatBytes(bytes: Long): String {
+        val units = arrayOf("B", "KB", "MB", "GB")
+        var value = bytes.toDouble().coerceAtLeast(0.0)
+        var unitIndex = 0
+
+        while (value >= 1024.0 && unitIndex < units.lastIndex) {
+            value /= 1024.0
+            unitIndex += 1
+        }
+
+        return if (unitIndex == 0) {
+            String.format(Locale.US, "%.0f %s", value, units[unitIndex])
+        } else {
+            String.format(Locale.US, "%.1f %s", value, units[unitIndex])
+        }
+    }
+
     private fun createOpenAppPendingIntent(): PendingIntent {
         val launchIntent = packageManager.getLaunchIntentForPackage(packageName)
             ?.apply {
@@ -249,3 +332,16 @@ private data class NotificationPayload(
     val endpointText: String,
     val detailsText: String,
 )
+
+private data class TrafficSample(
+    val bytesUp: Long,
+    val bytesDown: Long,
+    val timestampMillis: Long,
+)
+
+private data class TrafficState(
+    val upBytesPerSecond: Long,
+    val downBytesPerSecond: Long,
+    val totalBytesUp: Long,
+    val totalBytesDown: Long,
+)

android/app/src/main/java/org/flowseal/tgwsproxy/PythonProxyBridge.kt

@@ -4,6 +4,7 @@ import android.content.Context
 import com.chaquo.python.Python
 import com.chaquo.python.android.AndroidPlatform
 import java.io.File
+import org.json.JSONObject
 
 object PythonProxyBridge {
     private const val MODULE_NAME = "android_proxy_bridge"
@@ -27,6 +28,20 @@ object PythonProxyBridge {
         getModule(context).callAttr("stop_proxy")
     }
 
+    fun getTrafficStats(context: Context): ProxyTrafficStats {
+        if (!Python.isStarted()) {
+            return ProxyTrafficStats()
+        }
+
+        val payload = getModule(context).callAttr("get_runtime_stats_json").toString()
+        val json = JSONObject(payload)
+        return ProxyTrafficStats(
+            bytesUp = json.optLong("bytes_up", 0L),
+            bytesDown = json.optLong("bytes_down", 0L),
+            running = json.optBoolean("running", false),
+        )
+    }
+
     private fun getModule(context: Context) =
         getPython(context.applicationContext).getModule(MODULE_NAME)
 
@@ -37,3 +52,9 @@ object PythonProxyBridge {
         return Python.getInstance()
     }
 }
+
+data class ProxyTrafficStats(
+    val bytesUp: Long = 0L,
+    val bytesDown: Long = 0L,
+    val running: Boolean = false,
+)

android/app/src/main/python/android_proxy_bridge.py

@@ -1,10 +1,12 @@
 import os
 import threading
 import time
+import json
 from pathlib import Path
 from typing import Iterable, Optional
 
 from proxy.app_runtime import ProxyAppRuntime
+import proxy.tg_ws_proxy as tg_ws_proxy
 
 
 _RUNTIME_LOCK = threading.RLock()
@@ -49,6 +51,7 @@ def start_proxy(app_dir: str, host: str, port: int,
 
         _LAST_ERROR = None
         os.environ["TG_WS_PROXY_CRYPTO_BACKEND"] = "python"
+        tg_ws_proxy.reset_stats()
 
         runtime = ProxyAppRuntime(
             Path(app_dir),
@@ -107,3 +110,12 @@ def is_running() -> bool:
 
 def get_last_error() -> Optional[str]:
     return _LAST_ERROR
+
+
+def get_runtime_stats_json() -> str:
+    with _RUNTIME_LOCK:
+        running = bool(_RUNTIME and _RUNTIME.is_proxy_running())
+
+    payload = dict(tg_ws_proxy.get_stats_snapshot())
+    payload["running"] = running
+    return json.dumps(payload)

android/app/src/main/res/values/strings.xml

@@ -36,9 +36,7 @@
     <string name="notification_starting">SOCKS5 %1$s:%2$d • starting embedded Python</string>
     <string name="notification_running">SOCKS5 %1$s:%2$d • proxy active</string>
     <string name="notification_endpoint">%1$s:%2$d</string>
-    <string name="notification_details">SOCKS5 endpoint: %1$s:%2$d\nDC mappings: %3$d\nVerbose logging: %4$s\nTap to open the app, or stop the service from this notification.</string>
-    <string name="notification_verbose_on">enabled</string>
-    <string name="notification_verbose_off">disabled</string>
+    <string name="notification_details">DC mappings: %1$d\nTraffic: ↑ %2$s/s ↓ %3$s/s\nTransferred: ↑ %4$s ↓ %5$s</string>
     <string name="notification_action_stop">Stop</string>
     <string name="saved_config_invalid">Saved proxy settings are invalid.</string>
     <string name="proxy_start_failed_generic">Failed to start embedded Python proxy.</string>