3. Teori: Core ML Runtime Pipeline

.mlpackage / .mlmodelc
        │
        ▼
  MLModel.load() ──── mengcompile model ke format native hardware
        │
        ├── Neural Engine path (ANE) ← operasi yang support ANE
        ├── GPU path (Metal) ← operasi yang support GPU
        └── CPU path (BNNS/Accelerate) ← fallback atau CPU-only ops
        │
        ▼
  model.prediction(input:) ──── dispatch ke compute unit terpilih
        │
        ├── Input preprocessing (normalization, reshape)
        ├── Layer-by-layer computation
        └── Output postprocessing
        │
        ▼
  MLFeatureProvider (output) ──── hasil dikembalikan ke caller

// Inspect compute plan — mana yang ANE, GPU, CPU
let modelURL = Bundle.main.url(forResource: "MyModel", withExtension: "mlpackage")!
let compiledURL = try await MLModel.compileModel(at: modelURL)
let model = try MLModel(contentsOf: compiledURL)

// iOS 17+: MLComputePlan
if #available(iOS 17, *) {
    let plan = try await MLComputePlan.load(contentsOf: modelURL, configuration: .init())

    // Inspect structure: mana layers yang jalan di ANE vs GPU vs CPU
    plan.modelStructure  // MLModelStructure object
}

// Download model dari server, compile, simpan
func downloadAndPrepareModel(from url: URL) async throws -> URL {
    // 1. Download
    let (downloadedURL, _) = try await URLSession.shared.download(from: url)

    // 2. Pindahkan ke lokasi permanen
    let modelsDirectory = try FileManager.default
        .url(for: .documentDirectory, in: .userDomainMask, appropriateFor: nil, create: true)
        .appending(component: "models")

    try FileManager.default.createDirectory(at: modelsDirectory, withIntermediateDirectories: true)

    let packageURL = modelsDirectory.appending(component: "downloaded.mlpackage")
    if FileManager.default.fileExists(atPath: packageURL.path) {
        try FileManager.default.removeItem(at: packageURL)
    }
    try FileManager.default.moveItem(at: downloadedURL, to: packageURL)

    // 3. Compile (async, bisa lama untuk model besar)
    let compiledURL = try await MLModel.compileModel(at: packageURL)

    // 4. Pindahkan compiled model ke lokasi permanen
    let permanentCompiledURL = modelsDirectory.appending(component: "model.mlmodelc")
    if FileManager.default.fileExists(atPath: permanentCompiledURL.path) {
        try FileManager.default.removeItem(at: permanentCompiledURL)
    }
    try FileManager.default.moveItem(at: compiledURL, to: permanentCompiledURL)

    return permanentCompiledURL
}