thoughtsync/android/app/build.gradle.kts

import javax.inject.Inject

plugins {
    alias(libs.plugins.android.application)
    alias(libs.plugins.compose.compiler)
}

// The Cargo workspace root — two levels up from android/app.
val workspaceRoot: Directory = layout.projectDirectory.dir("../..")

// The ABIs a release APK carries. arm64 is essentially every real device; armv7
// covers older 32-bit hardware; the two x86 targets are what emulators run on, and
// dropping them would make the app untestable on a desktop emulator (the reason
// x86_64 was added to the old Tauri lane in task 1864).
val androidAbis = listOf("arm64-v8a", "armeabi-v7a", "x86", "x86_64")

/**
 * Cross-compile `thoughtsync-ffi` for each Android ABI and drop the resulting
 * `.so` into jniLibs, where AGP packages it.
 *
 * `ExecOperations` injected rather than `project.exec`: the latter was REMOVED in
 * Gradle 9, and reaching for `project` at execution time is also what breaks the
 * configuration cache this build has enabled.
 */
abstract class CargoNdkBuild : DefaultTask() {
    @get:Inject
    abstract val execOps: ExecOperations

    @get:InputFiles
    abstract val rustSources: ConfigurableFileCollection

    @get:Input
    abstract val abis: ListProperty<String>

    @get:Input
    abstract val cargoProfile: Property<String>

    @get:Internal
    abstract val workspaceDir: DirectoryProperty

    @get:OutputDirectory
    abstract val jniLibsDir: DirectoryProperty

    @TaskAction
    fun build() {
        val args = mutableListOf("ndk")
        abis.get().forEach { abi ->
            args += "-t"
            args += abi
        }
        args += listOf("-o", jniLibsDir.get().asFile.absolutePath, "build", "-p", "thoughtsync-ffi")
        // --locked so an Android build cannot silently re-resolve the workspace
        // lockfile the desktop lanes are gated on.
        args += "--locked"
        if (cargoProfile.get() == "release") args += "--release"

        execOps.exec {
            commandLine(listOf("cargo") + args)
            workingDir = workspaceDir.get().asFile
        }
    }
}

/**
 * Generate the Kotlin bindings FROM the freshly built `.so`.
 *
 * `--library` mode reads uniffi's metadata straight out of the compiled artifact,
 * so the bindings can never describe a different version of the Rust than the one
 * being packaged — which is the failure the whole in-workspace generator setup
 * exists to prevent.
 */
abstract class UniffiBindgen : DefaultTask() {
    @get:Inject
    abstract val execOps: ExecOperations

    @get:InputFile
    abstract val libraryFile: RegularFileProperty

    @get:Internal
    abstract val workspaceDir: DirectoryProperty

    @get:OutputDirectory
    abstract val outputDir: DirectoryProperty

    @TaskAction
    fun generate() {
        val out = outputDir.get().asFile
        out.deleteRecursively()
        out.mkdirs()
        execOps.exec {
            commandLine(
                "cargo",
                "run",
                "--locked",
                "-p",
                "thoughtsync-uniffi-bindgen",
                "--",
                "generate",
                "--library",
                libraryFile.get().asFile.absolutePath,
                "--language",
                "kotlin",
                "--out-dir",
                out.absolutePath,
            )
            workingDir = workspaceDir.get().asFile
        }
    }
}

// Only the Rust that actually affects the .so. Deliberately NOT the workspace
// directory: that would make Gradle hash target/, which is gigabytes.
val rustInputs =
    files(
        workspaceRoot.dir("core/src"),
        workspaceRoot.dir("android/ffi/src"),
        workspaceRoot.file("core/Cargo.toml"),
        workspaceRoot.file("android/ffi/Cargo.toml"),
        workspaceRoot.file("Cargo.toml"),
        workspaceRoot.file("Cargo.lock"),
    )

val jniLibsOut = layout.buildDirectory.dir("rustJniLibs")
val bindingsOut = layout.buildDirectory.dir("generated/uniffi")

val cargoNdkDebug =
    tasks.register<CargoNdkBuild>("cargoNdkDebug") {
        description = "Cross-compile thoughtsync-ffi for the Android ABIs (debug)."
        rustSources.from(rustInputs)
        abis.set(androidAbis)
        cargoProfile.set("debug")
        workspaceDir.set(workspaceRoot)
        jniLibsDir.set(jniLibsOut)
    }

val generateBindings =
    tasks.register<UniffiBindgen>("generateUniffiBindings") {
        description = "Generate the Kotlin bindings from the compiled .so."
        dependsOn(cargoNdkDebug)
        // arm64 is arbitrary — every ABI carries the same uniffi metadata, and
        // reading one is cheaper than reading four.
        libraryFile.set(jniLibsOut.map { it.file("arm64-v8a/libthoughtsync_ffi.so") })
        workspaceDir.set(workspaceRoot)
        outputDir.set(bindingsOut)
    }

android {
    namespace = "com.fabledsword.thoughtsync"
    compileSdk = 36

    defaultConfig {
        applicationId = "com.fabledsword.thoughtsync"
        // 26 (Android 8, 2017) matches Minstrel and clears the NDK's floor with
        // room to spare.
        minSdk = 26
        targetSdk = 36
        // Injected by CI from the git tag + commit count for a release; "dev"
        // locally so the About screen reads honestly rather than claiming 1.0.
        val nameOverride =
            (project.findProperty("THOUGHTSYNC_VERSION_NAME") as String?)?.takeIf { it.isNotBlank() }
        val codeOverride =
            (project.findProperty("THOUGHTSYNC_VERSION_CODE") as String?)?.toIntOrNull()
        versionCode = codeOverride ?: 1
        versionName = nameOverride ?: "dev"

        // Package ONLY the ABIs we build for.
        //
        // Without this the APK also carries armeabi, mips and mips64 — dead
        // architectures Android dropped years ago, which arrive because JNA's
        // .aar still ships a libjnidispatch.so for each. They can never be
        // loaded on any device this app supports, so they are pure payload.
        ndk {
            abiFilters += androidAbis
        }
    }

    buildTypes {
        release {
            isMinifyEnabled = false
            proguardFiles(getDefaultProguardFile("proguard-android-optimize.txt"), "proguard-rules.pro")
            // Signing is deliberately absent. A release keystore that has passed
            // through an agent session or shell history is compromised by
            // construction (Scribe task 2136) — it has to be generated by the
            // operator and reach CI only as a secret. Until then a release build
            // is unsigned and CI builds debug.
        }
    }

    compileOptions {
        sourceCompatibility = JavaVersion.VERSION_17
        targetCompatibility = JavaVersion.VERSION_17
    }

    buildFeatures {
        compose = true
    }

    packaging {
        resources.excludes += "/META-INF/{AL2.0,LGPL2.1}"
    }
}

/**
 * Register the `.so` and the generated bindings as GENERATED sources.
 *
 * NOT `sourceSets { ... srcDir(task) }`: AGP 9 rejects a Provider there outright,
 * because it cannot tell whether the directory holds generated (read-only) or
 * hand-written (read-write) files — a distinction the IDE needs. The Variant API
 * is the supported route and, unlike a bare path, `addGeneratedSourceDirectory`
 * carries the task dependency, so Kotlin cannot compile before the bindings
 * exist and the APK cannot package a stale `.so`.
 */
androidComponents {
    onVariants { variant ->
        variant.sources.kotlin?.addGeneratedSourceDirectory(generateBindings, UniffiBindgen::outputDir)
        variant.sources.jniLibs?.addGeneratedSourceDirectory(cargoNdkDebug, CargoNdkBuild::jniLibsDir)
    }
}

dependencies {
    implementation(libs.androidx.core.ktx)
    implementation(libs.androidx.activity.compose)
    implementation(libs.androidx.lifecycle.viewmodel.compose)
    implementation(libs.androidx.lifecycle.runtime.compose)
    implementation(libs.kotlinx.coroutines.android)

    // Required by the uniffi bindings — see the catalog note on the @aar
    // classifier; the plain jar builds fine and fails at runtime.
    implementation(variantOf(libs.jna) { artifactType("aar") })

    implementation(platform(libs.compose.bom))
    implementation(libs.compose.ui)
    implementation(libs.compose.ui.graphics)
    implementation(libs.compose.material3)
    implementation(libs.compose.ui.tooling.preview)
    debugImplementation(libs.compose.ui.tooling)

    testImplementation(libs.junit)
}