From 17bc9de8ca648f8d30fc960e3c3283a1b21adaf3 Mon Sep 17 00:00:00 2001
From: Hossain Khan <hello@hossain.dev>
Date: Sat, 31 Jan 2026 21:10:59 -0500
Subject: [PATCH] feat: Add WiFi signal strength (RSSI) reporting for BYOD
 devices

- Add getWifiSignalStrength() method to AndroidDeviceInfoProvider to retrieve WiFi RSSI in dBm
- Add RSSI header parameter to TrmnlApiService.getNextDisplayData() API call
- Update TrmnlDisplayRepository to fetch and send WiFi signal strength to TRMNL API for BYOD devices
- Add ACCESS_WIFI_STATE permission to AndroidManifest.xml
- RSSI values match firmware implementation (dBm scale, -100 to 0)
- Only sends RSSI for BYOD device type to match firmware behavior

This enables the TRMNL API to receive WiFi signal strength data from Android
devices for monitoring and diagnostics, matching the functionality of the
TRMNL firmware devices.
---
 app/src/main/AndroidManifest.xml              |  1 +
 .../android/data/TrmnlDisplayRepository.kt    |  7 +++++
 .../trmnl/android/network/TrmnlApiService.kt  |  6 ++++
 .../android/util/AndroidDeviceInfoProvider.kt | 30 ++++++++++++++++++-
 4 files changed, 43 insertions(+), 1 deletion(-)

diff --git a/app/src/main/AndroidManifest.xml b/app/src/main/AndroidManifest.xml
index f020645..6c78770 100644
--- a/app/src/main/AndroidManifest.xml
+++ b/app/src/main/AndroidManifest.xml
@@ -2,6 +2,7 @@
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:tools="http://schemas.android.com/tools">
     <uses-permission android:name="android.permission.INTERNET" />
+    <uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
 
     <application
         android:name=".TrmnlDisplayMirrorApp"
diff --git a/app/src/main/java/ink/trmnl/android/data/TrmnlDisplayRepository.kt b/app/src/main/java/ink/trmnl/android/data/TrmnlDisplayRepository.kt
index 76401ff..0b11321 100644
--- a/app/src/main/java/ink/trmnl/android/data/TrmnlDisplayRepository.kt
+++ b/app/src/main/java/ink/trmnl/android/data/TrmnlDisplayRepository.kt
@@ -75,6 +75,13 @@ class TrmnlDisplayRepository
                         // TEMP FIX: Use Base64 encoding to avoid relative path issue
                         // See https://github.com/usetrmnl/trmnl-android/issues/76#issuecomment-2980018109
                         // useBase64 = trmnlDeviceConfig.type == TrmnlDeviceType.BYOS, // Disabled for now
+                        rssi =
+                            if (trmnlDeviceConfig.type == TrmnlDeviceType.BYOD) {
+                                // Send WiFi signal strength (RSSI) if available for BYOD devices only
+                                androidDeviceInfoProvider.getWifiSignalStrength()
+                            } else {
+                                null
+                            },
                     )
 
             when (result) {
diff --git a/app/src/main/java/ink/trmnl/android/network/TrmnlApiService.kt b/app/src/main/java/ink/trmnl/android/network/TrmnlApiService.kt
index f9f51a2..7b815e3 100644
--- a/app/src/main/java/ink/trmnl/android/network/TrmnlApiService.kt
+++ b/app/src/main/java/ink/trmnl/android/network/TrmnlApiService.kt
@@ -87,10 +87,13 @@ interface TrmnlApiService {
      *
      * NOTE: This API always loads the next plugin image from the playlist.
      *
+     * See [API Doc](https://docs.trmnl.com/go/private-api/screens) for additional details.
+     *
      * @param fullApiUrl The complete API URL to call
      * @param accessToken The device's API key (required)
      * @param deviceMacId The device's MAC address (optional)
      * @param useBase64 Whether to request Base64-encoded image data (optional)
+     * @param rssi WiFi signal strength in dBm (optional, -100 to 0). See https://github.com/usetrmnl/trmnl-firmware/blob/main/src/api-client/display.cpp for additional references.
      *
      * @see getCurrentDisplayData
      */
@@ -100,6 +103,7 @@ interface TrmnlApiService {
         @Header("access-token") accessToken: String,
         @Header("ID") deviceMacId: String? = null,
         @Header("BASE64") useBase64: Boolean? = null,
+        @Header("RSSI") rssi: Int? = null,
     ): ApiResult<TrmnlDisplayResponse, Unit>
 
     /**
@@ -107,6 +111,8 @@ interface TrmnlApiService {
      *
      * NOTE: This API always loads the current plugin image from the playlist.
      *
+     * See [API Doc](https://docs.trmnl.com/go/private-api/screens) for additional details.
+     *
      * @see getNextDisplayData
      */
     @GET
diff --git a/app/src/main/java/ink/trmnl/android/util/AndroidDeviceInfoProvider.kt b/app/src/main/java/ink/trmnl/android/util/AndroidDeviceInfoProvider.kt
index 933fb34..610a199 100644
--- a/app/src/main/java/ink/trmnl/android/util/AndroidDeviceInfoProvider.kt
+++ b/app/src/main/java/ink/trmnl/android/util/AndroidDeviceInfoProvider.kt
@@ -1,6 +1,7 @@
 package ink.trmnl.android.util
 
 import android.content.Context
+import android.net.wifi.WifiManager
 import android.os.BatteryManager
 import com.squareup.anvil.annotations.optional.SingleIn
 import ink.trmnl.android.di.AppScope
@@ -12,7 +13,7 @@ import javax.inject.Inject
  * Provider class for accessing Android device information.
  *
  * This class provides utility methods to retrieve device-specific information
- * such as battery level, which can be used for reporting to the TRMNL API.
+ * such as battery level and WiFi signal strength, which can be used for reporting to the TRMNL API.
  */
 @SingleIn(AppScope::class)
 class AndroidDeviceInfoProvider
@@ -36,4 +37,31 @@ class AndroidDeviceInfoProvider
                 Timber.e(e, "Failed to get battery level")
                 null
             }
+
+        /**
+         * Gets the current WiFi signal strength (RSSI) of the Android device.
+         *
+         * RSSI (Received Signal Strength Indicator) is measured in dBm and typically
+         * ranges from -100 (weakest) to 0 (strongest).
+         *
+         * @return WiFi signal strength in dBm, or null if unable to retrieve or WiFi is not connected
+         */
+        @Suppress("DEPRECATION") // WifiInfo.rssi is still the standard way to get signal strength
+        fun getWifiSignalStrength(): Int? =
+            try {
+                val wifiManager = context.applicationContext.getSystemService(Context.WIFI_SERVICE) as? WifiManager
+                val wifiInfo = wifiManager?.connectionInfo
+                val rssi = wifiInfo?.rssi
+
+                if (rssi != null && rssi != -127) { // -127 (`INVALID_RSSI`) indicates no signal
+                    Timber.i("Current WiFi signal strength (RSSI): $rssi dBm")
+                    rssi
+                } else {
+                    Timber.d("WiFi not connected or signal unavailable")
+                    null
+                }
+            } catch (e: Exception) {
+                Timber.e(e, "Failed to get WiFi signal strength")
+                null
+            }
     }