Implement Wi-Fi scanning flow and Android build plumbing

.gitignore

@@ -1,3 +1,16 @@
-# Generated binary assets
-__pycache__/
-gradle/wrapper/gradle-wrapper.jar
+# Gradle and build outputs
+.gradle/
+build/
+app/build/
+
+# Local Android Studio config
+.idea/
+*.iml
+local.properties
+
+# Generated assets from bootstrap
+app/src/main/assets/
+app/src/main/res/drawable/*.png
+
+# OS cruft
+.DS_Store

README.md

@@ -1,32 +1,39 @@
 # DroneDetectAndroid
 
-This repo hosts Android-side utilities for drone rotor detection.
-Binary assets (TensorFlow Lite model and icons) are stored in base64 to
-keep the repo lean for air-gapped deployments.
+Android-side utilities for rotor detection and Wi‑Fi reconnaissance. Assets ship as base64 to keep the repo lean for air-gapped deployments and are restored automatically during Gradle builds.
 
 ## Bootstrap
 
-After cloning, restore the binary assets:
+After cloning, restore the binary assets (TensorFlow Lite model and PNG drawables):
 
 ```bash
 python3 scripts/bootstrap_assets.py
 ```
 
-This will recreate the `rotor_v1.tflite` model and the required PNG
-drawables under `app/src/main/...`.
+Gradle also depends on this script via the `preBuild` hook, so IDE and CI builds will automatically decode assets into `app/src/main/...` if Python is available.
 
 ## Pipeline
 
-1. **Asset bootstrap** – Decode the model and icons from `assets/*.b64` using the script above. Generated files land under `app/src/main/...`.
-2. **Runtime wiring** – `MainActivity` creates a `DroneSignalDetector`, which launches a coroutine to fetch flight data and schedule Wi‑Fi scans.
-3. **Scan handling** – `WifiScanReceiver` receives scan results. Future work will feed the TFLite model for rotor classification.
+1. **Asset bootstrap** – Decode the model and icons from `assets/*.b64` using the script above (or let Gradle call it).
+2. **Runtime wiring** – `MainActivity` requests Wi‑Fi/location permissions, wires a simple UI, and calls `DroneSignalDetector.startScan()`.
+3. **Scan handling** – `DroneSignalDetector` schedules repeated `WifiManager.startScan()` calls, ingests stub flight data, and surfaces scan results plus the last telemetry snapshot to the UI via callbacks.
+
+## Building
+
+This repo ships a minimal Gradle wrapper script for offline/air-gapped work. Supply a compatible `gradle/wrapper/gradle-wrapper.jar` (from Gradle 8.2.1) in your environment, then run:
+
+```bash
+./gradlew assembleDebug
+```
+
+If you prefer a hosted toolchain, open the project in Android Studio (Giraffe+), accept SDK prompts, and build the `app` module. Remember to run the asset bootstrap script if Python is missing from your build host.
 
 ## Testing
 
-Verify the asset bootstrap step restores the binaries:
+To validate the asset bootstrap step:
 
 ```bash
 python3 scripts/bootstrap_assets.py
 ```
 
-Each asset should report a `decoded` message. Remove the generated `app/src/main/assets` and `app/src/main/res` directories after testing to keep the repo text‑only.
+Each asset should report a `decoded` message. Remove the generated `app/src/main/assets` and `app/src/main/res/drawable` contents after testing to keep the repo text‑only.

app/build.gradle

@@ -0,0 +1,68 @@
+plugins {
+    id "com.android.application"
+    id "org.jetbrains.kotlin.android"
+}
+
+android {
+    namespace "com.example.dronedetect"
+    compileSdk = 34
+
+    defaultConfig {
+        applicationId = "com.example.dronedetect"
+        minSdk = 26
+        targetSdk = 34
+        versionCode = 1
+        versionName = "1.0"
+
+        testInstrumentationRunner = "androidx.test.runner.AndroidJUnitRunner"
+        vectorDrawables {
+            useSupportLibrary = true
+        }
+    }
+
+    buildTypes {
+        release {
+            isMinifyEnabled = false
+            proguardFiles(
+                getDefaultProguardFile("proguard-android-optimize.txt"),
+                "proguard-rules.pro"
+            )
+        }
+        debug {
+            isMinifyEnabled = false
+        }
+    }
+
+    compileOptions {
+        sourceCompatibility = JavaVersion.VERSION_11
+        targetCompatibility = JavaVersion.VERSION_11
+    }
+    kotlinOptions {
+        jvmTarget = "11"
+    }
+
+    buildFeatures {
+        viewBinding = true
+    }
+
+    tasks.named("preBuild") {
+        dependsOn("bootstrapAssets")
+    }
+}
+
+val bootstrapAssets by tasks.registering { task ->
+    task.group = "assets"
+    task.description = "Decode bundled base64 assets into their binary forms"
+    task.doLast {
+        exec {
+            commandLine("python3", rootProject.file("scripts/bootstrap_assets.py").absolutePath)
+        }
+    }
+}
+
+dependencies {
+    implementation("androidx.core:core-ktx:1.12.0")
+    implementation("androidx.appcompat:appcompat:1.6.1")
+    implementation("com.google.android.material:material:1.11.0")
+    implementation("androidx.constraintlayout:constraintlayout:2.1.4")
+}

app/proguard-rules.pro

@@ -0,0 +1 @@
+# Keep file intentionally minimal; add rules when obfuscation is enabled.

app/src/main/AndroidManifest.xml

@@ -0,0 +1,34 @@
+<?xml version="1.0" encoding="utf-8"?>
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    package="com.example.dronedetect">
+
+    <uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
+    <uses-permission android:name="android.permission.CHANGE_WIFI_STATE" />
+    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
+    <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
+    <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
+    <uses-permission
+        android:name="android.permission.NEARBY_WIFI_DEVICES"
+        android:usesPermissionFlags="neverForLocation"
+        android:required="false" />
+
+    <uses-feature android:name="android.hardware.wifi" android:required="true" />
+
+    <application
+        android:allowBackup="true"
+        android:icon="@drawable/drone_icon"
+        android:label="@string/app_name"
+        android:roundIcon="@drawable/drone_icon"
+        android:supportsRtl="true"
+        android:theme="@style/Theme.DroneDetect">
+        <activity
+            android:name=".MainActivity"
+            android:exported="true">
+            <intent-filter>
+                <action android:name="android.intent.action.MAIN" />
+
+                <category android:name="android.intent.category.LAUNCHER" />
+            </intent-filter>
+        </activity>
+    </application>
+</manifest>

app/src/main/java/com/example/dronedetect/DroneSignalDetector.kt

@@ -3,42 +3,100 @@ package com.example.dronedetect
 import android.content.BroadcastReceiver
 import android.content.Context
 import android.content.Intent
+import android.content.IntentFilter
+import android.net.wifi.ScanResult
 import android.net.wifi.WifiManager
 import android.os.Handler
 import android.os.Looper
+import android.util.Log
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.SupervisorJob
 import kotlinx.coroutines.cancel
 import kotlinx.coroutines.launch
 import kotlinx.coroutines.withContext
+import java.time.Instant
 
-class DroneSignalDetector(private val context: Context) {
+class DroneSignalDetector(
+    private val context: Context,
+    private val onResults: (List<ScanResult>, FlightSnapshot) -> Unit = { _, _ -> }
+) {
     private val handler = Handler(Looper.getMainLooper())
     private val wifiManager = context.applicationContext.getSystemService(Context.WIFI_SERVICE) as WifiManager
-    private val receiver = WifiScanReceiver()
-    private val scope = CoroutineScope(SupervisorJob() + Dispatchers.IO)
+    private val receiver = WifiScanReceiver(wifiManager, ::handleScanResults)
+    private var scanScope = CoroutineScope(SupervisorJob() + Dispatchers.IO)
+    private var isScanning = false
+    private var latestFlightData: FlightSnapshot = FlightSnapshot(timestamp = Instant.now(), source = "bootstrap", payload = emptyMap())
 
     fun startScan() {
-        scope.launch {
-            fetchFlightData()
-            // TODO: implement scanning logic
-        }
+        if (isScanning) return
+        isScanning = true
+        context.registerReceiver(receiver, IntentFilter(WifiManager.SCAN_RESULTS_AVAILABLE_ACTION))
+        scanScope.launch { fetchFlightData() }
+        requestScan()
     }
 
     suspend fun fetchFlightData() = withContext(Dispatchers.IO) {
-        // TODO: implement fetching flight data
+        // Placeholder for real RF/telemetry ingestion.
+        // Here we stamp a deterministic payload so downstream processing can
+        // align Wi-Fi RSSI snapshots with the last known telemetry sample.
+        latestFlightData = FlightSnapshot(
+            timestamp = Instant.now(),
+            source = "local_stub",
+            payload = mapOf(
+                "note" to "Replace with CSI/telemetry feed",
+                "status" to "idle"
+            )
+        )
+        Log.d(TAG, "Flight data refreshed at ${latestFlightData.timestamp}")
     }
 
     fun stopScan() {
+        if (!isScanning) return
+        isScanning = false
         handler.removeCallbacksAndMessages(null)
-        context.unregisterReceiver(receiver)
-        scope.cancel()
+        runCatching { context.unregisterReceiver(receiver) }
+        scanScope.cancel()
+        scanScope = CoroutineScope(SupervisorJob() + Dispatchers.IO)
+    }
+
+    private fun requestScan() {
+        val started = wifiManager.startScan()
+        if (!started) {
+            Log.w(TAG, "Wi-Fi scan request rejected by platform")
+        }
+        handler.postDelayed({
+            if (isScanning) {
+                requestScan()
+            }
+        }, SCAN_INTERVAL_MS)
+    }
+
+    private fun handleScanResults(results: List<ScanResult>) {
+        if (!isScanning) return
+        onResults(results, latestFlightData)
+    }
+
+    companion object {
+        private const val TAG = "DroneSignalDetector"
+        private const val SCAN_INTERVAL_MS = 10_000L
     }
 }
 
-class WifiScanReceiver : BroadcastReceiver() {
+data class FlightSnapshot(
+    val timestamp: Instant,
+    val source: String,
+    val payload: Map<String, String>
+)
+
+private class WifiScanReceiver(
+    private val wifiManager: WifiManager,
+    private val onResults: (List<ScanResult>) -> Unit
+) : BroadcastReceiver() {
     override fun onReceive(context: Context?, intent: Intent?) {
-        // TODO: handle scan results
+        val action = intent?.action ?: return
+        if (action != WifiManager.SCAN_RESULTS_AVAILABLE_ACTION) return
+        val results = wifiManager.scanResults.orEmpty()
+        onResults(results)
     }
 }