From 80498b921712e805fe253565867acd99cce18f0c Mon Sep 17 00:00:00 2001
From: Philip Gregor <pgregorr@amazon.com>
Date: Mon, 1 Apr 2024 11:13:52 -0700
Subject: [PATCH] Android - implement ChipDnssdStopBrowse in the core SDK

---
 .../casting/DiscoveryExampleFragment.java     | 48 ++++++-------------
 .../cpp/core/CastingPlayerDiscovery-JNI.cpp   |  7 +++
 .../fragment_matter_discovery_example.xml     | 16 +++++--
 .../App/app/src/main/res/values/strings.xml   |  6 ++-
 src/lib/dnssd/Discovery_ImplPlatform.cpp      |  2 +-
 src/lib/dnssd/platform/Dnssd.h                |  4 +-
 src/platform/android/DnssdImpl.cpp            | 22 ++++++++-
 .../platform/NsdManagerServiceBrowser.java    | 16 ++++++-
 8 files changed, 76 insertions(+), 45 deletions(-)

diff --git a/examples/tv-casting-app/android/App/app/src/main/java/com/matter/casting/DiscoveryExampleFragment.java b/examples/tv-casting-app/android/App/app/src/main/java/com/matter/casting/DiscoveryExampleFragment.java
index b847e17f5b7026..50b47c348d6f6b 100644
--- a/examples/tv-casting-app/android/App/app/src/main/java/com/matter/casting/DiscoveryExampleFragment.java
+++ b/examples/tv-casting-app/android/App/app/src/main/java/com/matter/casting/DiscoveryExampleFragment.java
@@ -38,9 +38,6 @@
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Optional;
-import java.util.concurrent.Executors;
-import java.util.concurrent.ScheduledExecutorService;
-import java.util.concurrent.ScheduledFuture;
 
 public class DiscoveryExampleFragment extends Fragment {
   private static final String TAG = DiscoveryExampleFragment.class.getSimpleName();
@@ -48,9 +45,7 @@ public class DiscoveryExampleFragment extends Fragment {
   private static final Long DISCOVERY_TARGET_DEVICE_TYPE = 35L;
   private static final int DISCOVERY_RUNTIME_SEC = 15;
   private TextView matterDiscoveryMessageTextView;
-  private static final ScheduledExecutorService executorService =
-      Executors.newSingleThreadScheduledExecutor();
-  private ScheduledFuture scheduledFutureTask;
+  private TextView matterDiscoveryErrorMessageTextView;
   private static final List<CastingPlayer> castingPlayerList = new ArrayList<>();
   private static ArrayAdapter<CastingPlayer> arrayAdapter;
 
@@ -164,15 +159,17 @@ public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
     matterDiscoveryMessageTextView.setText(
         getString(R.string.matter_discovery_message_initializing_text));
 
+      matterDiscoveryErrorMessageTextView =
+              getActivity().findViewById(R.id.matterDiscoveryErrorTextView);
+      matterDiscoveryErrorMessageTextView.setText(
+              getString(R.string.matter_discovery_error_message_initial));
+
     arrayAdapter = new CastingPlayerArrayAdapter(getActivity(), castingPlayerList);
     final ListView list = getActivity().findViewById(R.id.castingPlayerList);
     list.setAdapter(arrayAdapter);
 
     Log.d(TAG, "onViewCreated() creating callbacks");
 
-    // TODO: In following PRs. Enable startDiscoveryButton and stopDiscoveryButton when
-    //  stopDiscovery is implemented in the core Matter SDK DNS-SD API. Enable in
-    //  fragment_matter_discovery_example.xml
     Button startDiscoveryButton = getView().findViewById(R.id.startDiscoveryButton);
     startDiscoveryButton.setOnClickListener(
         v -> {
@@ -188,8 +185,6 @@ public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
         v -> {
           Log.i(TAG, "onViewCreated() stopDiscoveryButton button clicked. Calling stopDiscovery()");
           stopDiscovery();
-          Log.i(TAG, "onViewCreated() stopDiscoveryButton button clicked. Canceling future task");
-          scheduledFutureTask.cancel(true);
         });
 
     Button clearDiscoveryResultsButton = getView().findViewById(R.id.clearDiscoveryResultsButton);
@@ -198,6 +193,7 @@ public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
           Log.i(
               TAG, "onViewCreated() clearDiscoveryResultsButton button clicked. Clearing results");
           arrayAdapter.clear();
+          matterDiscoveryErrorMessageTextView.setText(getString(R.string.matter_discovery_error_message_initial));
         });
   }
 
@@ -219,11 +215,7 @@ public void onResume() {
   public void onPause() {
     super.onPause();
     Log.i(TAG, "onPause() called");
-    // stopDiscovery();
-    // Don't crash the app
-    if (scheduledFutureTask != null) {
-      scheduledFutureTask.cancel(true);
-    }
+    stopDiscovery();
   }
 
   /** Interface for notifying the host. */
@@ -235,6 +227,7 @@ public interface Callback {
 
   private boolean startDiscovery() {
     Log.i(TAG, "startDiscovery() called");
+    matterDiscoveryErrorMessageTextView.setText(getString(R.string.matter_discovery_error_message_initial));
 
     arrayAdapter.clear();
 
@@ -244,6 +237,7 @@ private boolean startDiscovery() {
         matterCastingPlayerDiscovery.addCastingPlayerChangeListener(castingPlayerChangeListener);
     if (err.hasError()) {
       Log.e(TAG, "startDiscovery() addCastingPlayerChangeListener() called, err Add: " + err);
+        matterDiscoveryErrorMessageTextView.setText(getString(R.string.matter_discovery_error_message_stop_before_starting) + err);
       return false;
     }
     // Start discovery
@@ -251,6 +245,7 @@ private boolean startDiscovery() {
     err = matterCastingPlayerDiscovery.startDiscovery(DISCOVERY_TARGET_DEVICE_TYPE);
     if (err.hasError()) {
       Log.e(TAG, "startDiscovery() startDiscovery() called, err Start: " + err);
+      matterDiscoveryErrorMessageTextView.setText(getString(R.string.matter_discovery_error_message_start_error) + err);
       return false;
     }
 
@@ -259,28 +254,12 @@ private boolean startDiscovery() {
     matterDiscoveryMessageTextView.setText(
         getString(R.string.matter_discovery_message_discovering_text));
 
-    // TODO: In following PRs. Enable this to auto-stop discovery after stopDiscovery is
-    //  implemented in the core Matter SDK DNS-SD API.
-    // Schedule a service to stop discovery and remove the CastingPlayerChangeListener
-    // Safe to call if discovery is not running
-    //    scheduledFutureTask =
-    //        executorService.schedule(
-    //            () -> {
-    //              Log.i(
-    //                  TAG,
-    //                  "startDiscovery() executorService "
-    //                      + DISCOVERY_RUNTIME_SEC
-    //                      + " seconds timer expired. Auto-calling stopDiscovery()");
-    //              stopDiscovery();
-    //            },
-    //            DISCOVERY_RUNTIME_SEC,
-    //            TimeUnit.SECONDS);
-
     return true;
   }
 
   private void stopDiscovery() {
     Log.i(TAG, "stopDiscovery() called");
+    matterDiscoveryErrorMessageTextView.setText(getString(R.string.matter_discovery_error_message_initial));
 
     // Stop discovery
     MatterError err = matterCastingPlayerDiscovery.stopDiscovery();
@@ -288,8 +267,8 @@ private void stopDiscovery() {
       Log.e(
           TAG,
           "stopDiscovery() MatterCastingPlayerDiscovery.stopDiscovery() called, err Stop: " + err);
+      matterDiscoveryErrorMessageTextView.setText(getString(R.string.matter_discovery_error_message_stop_error) + err);
     } else {
-      // TODO: In following PRs. Implement stop discovery in the Android core API.
       Log.d(TAG, "stopDiscovery() MatterCastingPlayerDiscovery.stopDiscovery() success");
     }
 
@@ -309,6 +288,7 @@ private void stopDiscovery() {
           TAG,
           "stopDiscovery() matterCastingPlayerDiscovery.removeCastingPlayerChangeListener() called, err Remove: "
               + err);
+      matterDiscoveryErrorMessageTextView.setText(getString(R.string.matter_discovery_error_message_stop_error) + err);
     }
   }
 }
diff --git a/examples/tv-casting-app/android/App/app/src/main/jni/cpp/core/CastingPlayerDiscovery-JNI.cpp b/examples/tv-casting-app/android/App/app/src/main/jni/cpp/core/CastingPlayerDiscovery-JNI.cpp
index 5981ab80bbd52e..c42a6d05ff0cb0 100644
--- a/examples/tv-casting-app/android/App/app/src/main/jni/cpp/core/CastingPlayerDiscovery-JNI.cpp
+++ b/examples/tv-casting-app/android/App/app/src/main/jni/cpp/core/CastingPlayerDiscovery-JNI.cpp
@@ -246,6 +246,13 @@ JNI_METHOD(jobject, removeCastingPlayerChangeListener)(JNIEnv * env, jobject, jo
 
         return support::convertMatterErrorFromCppToJava(CHIP_NO_ERROR);
     }
+    else if (DiscoveryDelegateImpl::GetInstance()->castingPlayerChangeListenerJavaObject.ObjectRef() == nullptr)
+    {
+        ChipLogError(AppServer,
+                     "CastingPlayerDiscovery-JNI::removeCastingPlayerChangeListener() Warning: Cannot remove listener. No "
+                     "listener was added");
+        return support::convertMatterErrorFromCppToJava(CHIP_NO_ERROR);
+    }
     else
     {
         ChipLogError(AppServer,
diff --git a/examples/tv-casting-app/android/App/app/src/main/res/layout/fragment_matter_discovery_example.xml b/examples/tv-casting-app/android/App/app/src/main/res/layout/fragment_matter_discovery_example.xml
index 1c3eb13ce6c486..3f3e3d987a5644 100644
--- a/examples/tv-casting-app/android/App/app/src/main/res/layout/fragment_matter_discovery_example.xml
+++ b/examples/tv-casting-app/android/App/app/src/main/res/layout/fragment_matter_discovery_example.xml
@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="utf-8"?>
-<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
+<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:tools="http://schemas.android.com/tools"
     android:layout_width="match_parent"
     android:layout_height="match_parent"
@@ -15,14 +15,14 @@
         android:padding="10sp">
 
         <Button
-            android:enabled="false"
+            android:enabled="true"
             android:id="@+id/startDiscoveryButton"
             android:layout_width="match_parent"
             android:layout_height="wrap_content"
             android:text="@string/matter_start_discovery_button_text" />
 
         <Button
-            android:enabled="false"
+            android:enabled="true"
             android:id="@+id/stopDiscoveryButton"
             android:layout_width="match_parent"
             android:layout_height="wrap_content"
@@ -49,5 +49,13 @@
             android:fadeScrollbars = "false" />
     </LinearLayout>
 
+    <TextView
+        android:id="@+id/matterDiscoveryErrorTextView"
+        android:layout_width="match_parent"
+        android:layout_height = "wrap_content"
+        android:text="string/matter_discovery_error_default_text"
+        android:textAlignment="center"
+        android:textAppearance="@style/TextAppearance.AppCompat.Small"
+        android:layout_alignParentBottom="true"/>
 
-</FrameLayout>
\ No newline at end of file
+</RelativeLayout>
\ No newline at end of file
diff --git a/examples/tv-casting-app/android/App/app/src/main/res/values/strings.xml b/examples/tv-casting-app/android/App/app/src/main/res/values/strings.xml
index de7849cec3554e..17578cbdd2e871 100644
--- a/examples/tv-casting-app/android/App/app/src/main/res/values/strings.xml
+++ b/examples/tv-casting-app/android/App/app/src/main/res/values/strings.xml
@@ -31,8 +31,12 @@
     <string name="matter_stop_discovery_button_text">Stop Discovery"</string>
     <string name="matter_clear_results_button_text">Clear Results"</string>
     <string name="matter_discovery_message_initializing_text">Initializing</string>
-    <string name="matter_discovery_message_discovering_text">Casting Players on-network:</string>
+    <string name="matter_discovery_message_discovering_text">Discovering Casting Players on-network:</string>
     <string name="matter_discovery_message_stopped_text">Discovery Stopped</string>
+    <string name="matter_discovery_error_message_initial">No errors to report</string>
+    <string name="matter_discovery_error_message_start_error">START DISCOVERY error. -</string>
+    <string name="matter_discovery_error_message_stop_before_starting">START DISCOVERY error. Discovery ongoing, STOP before STARTING. -</string>
+    <string name="matter_discovery_error_message_stop_error">STOP DISCOVERY error. -</string>
     <string name="matter_connection_next_button_text">Next</string>
     <string name="matter_action_selector_text">Select an action</string>
     <string name="matter_select_content_launcher_launch_url_button_text">Content Launcher Launch URL</string>
diff --git a/src/lib/dnssd/Discovery_ImplPlatform.cpp b/src/lib/dnssd/Discovery_ImplPlatform.cpp
index 3369f8c00b3b3b..0801a2d9eec19d 100644
--- a/src/lib/dnssd/Discovery_ImplPlatform.cpp
+++ b/src/lib/dnssd/Discovery_ImplPlatform.cpp
@@ -754,7 +754,7 @@ CHIP_ERROR DiscoveryImplPlatform::StopDiscovery(DiscoveryContext & context)
     const auto browseIdentifier = context.GetBrowseIdentifier().Value();
     context.ClearBrowseIdentifier();
 
-    return ChipDnssdStopBrowse(browseIdentifier);
+    return ChipDnssdStopBrowse(browseIdentifier, HandleNodeBrowse);
 }
 
 CHIP_ERROR DiscoveryImplPlatform::ReconfirmRecord(const char * hostname, Inet::IPAddress address, Inet::InterfaceId interfaceId)
diff --git a/src/lib/dnssd/platform/Dnssd.h b/src/lib/dnssd/platform/Dnssd.h
index 778e9bc05f1d9c..cb4a07e510a0cf 100644
--- a/src/lib/dnssd/platform/Dnssd.h
+++ b/src/lib/dnssd/platform/Dnssd.h
@@ -230,8 +230,10 @@ CHIP_ERROR ChipDnssdBrowse(const char * type, DnssdServiceProtocol protocol, chi
  *
  * @param browseIdentifier an identifier for a browse operation that came from
  *                         ChipDnssdBrowse.
+ * @param callback         The callback to call when the browse is stopped.
+ *
  */
-CHIP_ERROR ChipDnssdStopBrowse(intptr_t browseIdentifier);
+CHIP_ERROR ChipDnssdStopBrowse(intptr_t browseIdentifier, DnssdBrowseCallback callback = {});
 
 #if CHIP_DEVICE_LAYER_TARGET_DARWIN
 /**
diff --git a/src/platform/android/DnssdImpl.cpp b/src/platform/android/DnssdImpl.cpp
index 5f2e79b27b258f..ca503f7274ac9c 100644
--- a/src/platform/android/DnssdImpl.cpp
+++ b/src/platform/android/DnssdImpl.cpp
@@ -44,6 +44,7 @@ JniGlobalReference sBrowserObject;
 JniGlobalReference sMdnsCallbackObject;
 jmethodID sResolveMethod          = nullptr;
 jmethodID sBrowseMethod           = nullptr;
+jmethodID sStopBrowseMethod       = nullptr;
 jmethodID sGetTextEntryKeysMethod = nullptr;
 jmethodID sGetTextEntryDataMethod = nullptr;
 jclass sMdnsCallbackClass         = nullptr;
@@ -207,9 +208,24 @@ CHIP_ERROR ChipDnssdBrowse(const char * type, DnssdServiceProtocol protocol, Ine
     return CHIP_NO_ERROR;
 }
 
-CHIP_ERROR ChipDnssdStopBrowse(intptr_t browseIdentifier)
+CHIP_ERROR ChipDnssdStopBrowse(intptr_t browseIdentifier, DnssdBrowseCallback callback)
 {
-    return CHIP_ERROR_NOT_IMPLEMENTED;
+    VerifyOrReturnError(callback != nullptr, CHIP_ERROR_INVALID_ARGUMENT);
+    VerifyOrReturnError(sMdnsCallbackObject.HasValidObjectRef(), CHIP_ERROR_INCORRECT_STATE);
+
+    JNIEnv * env = JniReferences::GetInstance().GetEnvForCurrentThread();
+
+    env->CallVoidMethod(sBrowserObject.ObjectRef(), sStopBrowseMethod, reinterpret_cast<jlong>(callback), sMdnsCallbackObject.ObjectRef());
+
+    if (env->ExceptionCheck())
+    {
+        ChipLogError(Discovery, "Java exception in ChipDnssdStopBrowse");
+        env->ExceptionDescribe();
+        env->ExceptionClear();
+        return CHIP_JNI_ERROR_EXCEPTION_THROWN;
+    }
+    ChipLogProgress(AppServer, "PHILIPGREGOR DnssdlImpl.cpp ChipDnssdStopBrowse() success, return CHIP_NO_ERROR; 2");
+    return CHIP_NO_ERROR;
 }
 
 template <size_t N>
@@ -306,6 +322,8 @@ void InitializeWithObjects(jobject resolverObject, jobject browserObject, jobjec
 
     sBrowseMethod = env->GetMethodID(browserClass, "browse", "(Ljava/lang/String;JJLchip/platform/ChipMdnsCallback;)V");
 
+    sStopBrowseMethod = env->GetMethodID(browserClass, "stopDiscover", "(JLchip/platform/ChipMdnsCallback;)V");
+
     if (sResolveMethod == nullptr)
     {
         ChipLogError(Discovery, "Failed to access Resolver 'resolve' method");
diff --git a/src/platform/android/java/chip/platform/NsdManagerServiceBrowser.java b/src/platform/android/java/chip/platform/NsdManagerServiceBrowser.java
index f98acdfb1c7278..16cb6d1e7441d0 100644
--- a/src/platform/android/java/chip/platform/NsdManagerServiceBrowser.java
+++ b/src/platform/android/java/chip/platform/NsdManagerServiceBrowser.java
@@ -23,6 +23,7 @@
 import android.net.wifi.WifiManager;
 import android.net.wifi.WifiManager.MulticastLock;
 import android.os.Handler;
+import android.os.MessageQueue;
 import android.os.Looper;
 import android.util.Log;
 import java.util.ArrayList;
@@ -97,17 +98,22 @@ public void startDiscover(
 
   public void stopDiscover(final long callbackHandle, final ChipMdnsCallback chipMdnsCallback) {
     if (!callbackMap.containsKey(callbackHandle)) {
-      Log.d(TAG, "Invalid callbackHandle");
       return;
     }
 
+    MessageQueue queue = mainThreadHandler.getLooper().getQueue();
+    if (!queue.isIdle()) {
+      Log.i(TAG, "canceling scheduled browse timeout runnable");
+      mainThreadHandler.removeCallbacksAndMessages(null);
+    }
+
     NsdManagerDiscovery discovery = callbackMap.remove(callbackHandle);
     if (multicastLock.isHeld()) {
       multicastLock.release();
     }
 
+    discovery.setChipMdnsCallback(chipMdnsCallback);
     this.nsdManager.stopServiceDiscovery(discovery);
-    discovery.handleServiceBrowse(chipMdnsCallback);
   }
 
   public class NsdManagerDiscovery implements NsdManager.DiscoveryListener {
@@ -115,6 +121,7 @@ public class NsdManagerDiscovery implements NsdManager.DiscoveryListener {
     private long callbackHandle;
     private long contextHandle;
     private ArrayList<String> serviceNameList = new ArrayList<>();
+    private ChipMdnsCallback chipMdnsCallback;
 
     public NsdManagerDiscovery(String serviceType, long callbackHandle, long contextHandle) {
       this.serviceType = serviceType;
@@ -151,6 +158,7 @@ public void onStopDiscoveryFailed(String serviceType, int errorCode) {
     @Override
     public void onDiscoveryStopped(String serviceType) {
       Log.w(TAG, "Succeed to stop discovery service '" + serviceType);
+      this.handleServiceBrowse(chipMdnsCallback);
     }
 
     public void handleServiceBrowse(ChipMdnsCallback chipMdnsCallback) {
@@ -160,5 +168,9 @@ public void handleServiceBrowse(ChipMdnsCallback chipMdnsCallback) {
           callbackHandle,
           contextHandle);
     }
+
+    public void setChipMdnsCallback (final ChipMdnsCallback chipMdnsCallback) {
+      this.chipMdnsCallback = chipMdnsCallback;
+    }
   }
 }