build: add Android release APK packaging script

apps/chanora_flutter/android/app/build.gradle.kts

@@ -33,6 +33,24 @@ val releaseStorePassword = resolveSigningProp("CHANORA_RELEASE_STORE_PASSWORD")
 val releaseKeyAlias = resolveSigningProp("CHANORA_RELEASE_KEY_ALIAS")
 val releaseKeyPassword = resolveSigningProp("CHANORA_RELEASE_KEY_PASSWORD")
 val hasReleaseSigning = listOf(releaseStoreFile, releaseStorePassword, releaseKeyAlias, releaseKeyPassword).all { !it.isNullOrBlank() }
+val splitPerAbiRequested = gradle.startParameter.taskNames.any { taskName ->
+    taskName.contains("split-per-abi", ignoreCase = true)
+}
+val configuredAbiSet = listOf("arm64-v8a", "x86_64")
+val flutterTargetPlatformArg = gradle.startParameter.projectProperties["target-platform"]
+    ?.split(',')
+    ?.map { it.trim() }
+    ?.firstOrNull()
+val singleAbiFromFlutterTargetPlatform = when (flutterTargetPlatformArg) {
+    "android-arm64" -> "arm64-v8a"
+    "android-x64" -> "x86_64"
+    else -> null
+}
+val effectivePackagingAbis: List<String> = when {
+    singleAbiFromFlutterTargetPlatform != null -> listOf(singleAbiFromFlutterTargetPlatform)
+    splitPerAbiRequested -> configuredAbiSet
+    else -> configuredAbiSet
+}
 
 android {
     namespace = "app.chanora.chanora_flutter"
@@ -77,7 +95,7 @@ android {
             // ANDROID_PLATFORM as -D variables to the child cmake
             // invocation). See Cargo.toml [patch.crates-io] block and
             // docs/governance/product-decision-register.md DEC-032.
-            abiFilters += listOf("arm64-v8a", "x86_64")
+            abiFilters += effectivePackagingAbis
         }
     }
 
@@ -137,6 +155,16 @@ android {
         }
     }
 
+    packaging {
+        jniLibs {
+            if (singleAbiFromFlutterTargetPlatform != null) {
+                val excludedAbis = configuredAbiSet.filter { it != singleAbiFromFlutterTargetPlatform } +
+                    listOf("armeabi-v7a", "x86")
+                excludes += excludedAbis.map { abi -> "lib/$abi/**" }
+            }
+        }
+    }
+
     // SDD-109 item 2: Android App Bundle (.aab) split configuration.
     // Combined with the SDD-073 abiFilters set, this yields two
     // native splits (arm64-v8a, x86_64), per-language resource
@@ -155,7 +183,7 @@ android {
     }
 }
 
-// ONNX Runtime native library for Silero / TEN VAD.
+// ONNX Runtime native library for Silero VAD.
 // The ort crate (Rust) loads libonnxruntime.so via dlopen at runtime
 // (`load-dynamic` feature).  The AAR ships the .so for arm64-v8a,
 // armeabi-v7a, x86_64, x86.  AGP merges these into the APK/AAB.
@@ -229,7 +257,11 @@ val abiToRustTriple: Map<String, String> = mapOf(
 // `android.defaultConfig.ndk.abiFilters` declaration owned by SDD-073 item 4
 // so that the build-automation list and the AGP packaging list are guaranteed
 // in sync. Any unsupported ABI fails fast.
-val configuredAbis: List<String> = android.defaultConfig.ndk.abiFilters.toList()
+val configuredAbis: List<String> = when {
+    singleAbiFromFlutterTargetPlatform != null -> listOf(singleAbiFromFlutterTargetPlatform)
+    splitPerAbiRequested -> configuredAbiSet
+    else -> android.defaultConfig.ndk.abiFilters.toList()
+}
 configuredAbis.forEach { abi ->
     require(abiToRustTriple.containsKey(abi)) {
         "[SDD-118] ABI '$abi' is not supported by SDD-118; see SDD-073 item 4. " +
@@ -458,7 +490,7 @@ val abiToNdkSysrootTriple: Map<String, String> = mapOf(
     "arm64-v8a" to "aarch64-linux-android",
     "x86_64" to "x86_64-linux-android",
 )
-fun registerJniLibsCopyTask(profile: String): TaskProvider<Copy> {
+fun registerJniLibsCopyTask(profile: String): TaskProvider<Task> {
     val capitalized = profile.replaceFirstChar { it.uppercase() }
     val buildTask = if (profile == "release") buildRustBridgeRelease else buildRustBridgeDebug
 
@@ -468,16 +500,30 @@ fun registerJniLibsCopyTask(profile: String): TaskProvider<Copy> {
         .takeUnless { it.isNullOrBlank() }
         ?: android.ndkDirectory.absolutePath
 
-    return tasks.register<Copy>("copyRustBridgeJniLibs$capitalized") {
+    return tasks.register("copyRustBridgeJniLibs$capitalized") {
         group = "chanora_bridge"
-        description = "SDD-118 item 6 (extended): stage per-ABI libchanora_bridge.so + libc++_shared.so (profile=$profile) into src/main/jniLibs/."
+        description = "SDD-118 item 6 (extended): strip and stage per-ABI libchanora_bridge.so + libc++_shared.so (profile=$profile) into src/main/jniLibs/."
         dependsOn(buildTask)
-        duplicatesStrategy = DuplicatesStrategy.INCLUDE
-
+        val jniLibsDir = layout.projectDirectory.dir("src/main/jniLibs").asFile
+        val llvmStrip = file(
+            "$effectiveNdkPath/toolchains/llvm/prebuilt/$ndkHostTag/bin/llvm-strip"
+        )
+        doFirst {
+            jniLibsDir
+                .listFiles()
+                ?.filter { it.isDirectory && !configuredAbis.contains(it.name) }
+                ?.forEach { staleDir ->
+                    staleDir.deleteRecursively()
+                }
+        }
         configuredAbis.forEach { abi ->
             val triple = abiToRustTriple.getValue(abi)
             val sysrootTriple = abiToNdkSysrootTriple.getValue(abi)
             val bridgeSo = cargoWorkspaceRoot.resolve("target/$triple/$profile/libchanora_bridge.so")
+            val strippedBridgeSo = layout.buildDirectory
+                .file("intermediates/stripped_rust_jni/$profile/$abi/libchanora_bridge.so")
+                .get()
+                .asFile
             // SDD-118 item 6 (extended): also stage libc++_shared.so from the
             // NDK sysroot. libchanora_bridge.so is dynamically linked against
             // the NDK's shared C++ runtime (via audiopus_sys / opus-cpp and
@@ -487,28 +533,37 @@ fun registerJniLibsCopyTask(profile: String): TaskProvider<Copy> {
             val cxxSharedSo = file(
                 "$effectiveNdkPath/toolchains/llvm/prebuilt/$ndkHostTag/sysroot/usr/lib/$sysrootTriple/libc++_shared.so"
             )
-            from(bridgeSo) {
-                into(abi)
-            }
-            from(cxxSharedSo) {
-                into(abi)
-            }
             // SDD-118 item 8: input tracking for both staged sources so
             // Gradle correctly invalidates when either changes (e.g. NDK
             // version bump replacing libc++_shared.so).
             inputs.file(bridgeSo).withPropertyName("bridgeSo_$abi")
             inputs.file(cxxSharedSo).withPropertyName("cxxSharedSo_$abi")
-        }
-        into(layout.projectDirectory.dir("src/main/jniLibs"))
+            inputs.file(llvmStrip).withPropertyName("llvmStrip")
+            outputs.file(strippedBridgeSo)
+            outputs.file(File(jniLibsDir, "$abi/libchanora_bridge.so"))
+            outputs.file(File(jniLibsDir, "$abi/libc++_shared.so"))
 
-        // SDD-118 item 8: declare staged outputs so Gradle can track them.
-        configuredAbis.forEach { abi ->
-            outputs.file(
-                layout.projectDirectory.file("src/main/jniLibs/$abi/libchanora_bridge.so")
-            )
-            outputs.file(
-                layout.projectDirectory.file("src/main/jniLibs/$abi/libc++_shared.so")
-            )
+            doLast {
+                val abiDir = File(jniLibsDir, abi)
+                abiDir.mkdirs()
+                strippedBridgeSo.parentFile.mkdirs()
+                bridgeSo.copyTo(strippedBridgeSo, overwrite = true)
+                project.exec {
+                    commandLine(
+                        llvmStrip.absolutePath,
+                        "--strip-debug",
+                        strippedBridgeSo.absolutePath,
+                    )
+                }
+                strippedBridgeSo.copyTo(
+                    File(abiDir, "libchanora_bridge.so"),
+                    overwrite = true,
+                )
+                cxxSharedSo.copyTo(
+                    File(abiDir, "libc++_shared.so"),
+                    overwrite = true,
+                )
+            }
         }
     }
 }