import Foundation
import Darwin
#if ELIZA_IOS_FULL_BUN_ENGINE
import ElizaBunEngine
#endif

private let fullBunHostCallCallback: @convention(c) (
    UnsafePointer<CChar>?,
    UnsafePointer<CChar>?,
    Int32
) -> UnsafeMutablePointer<CChar>? = { methodPtr, payloadPtr, timeoutMs in
    let method = methodPtr.map { String(cString: $0) } ?? ""
    let payloadJson = payloadPtr.map { String(cString: $0) } ?? "null"
    let response = FullBunEngineHost.shared.handleHostCall(
        method: method,
        payloadJson: payloadJson,
        timeoutMs: timeoutMs
    )
    return strdup(response)
}

/// Host for the real Bun iOS engine framework.
///
/// Full-engine/App Store builds link `ElizaBunEngine.xcframework` directly so
/// the shipped app does not import dynamic loader APIs. Compatibility builds
/// keep the optional loader path only in DEBUG development builds without
/// embedding the full engine framework. Release builds without the direct-link
/// flag fail closed.
///
/// IPC security model (full-Bun path):
/// - Transport: NDJSON over anonymous stdio pipes. No TCP port is opened by the
///   native side. `bun_start(...)` receives the read end of the parent's stdin
///   pipe and the write end of its stdout pipe; no other network socket is
///   created by the shim.
/// - Input validation: the C shim (`eliza_bun_engine_shim.c`) validates all
///   NDJSON frames before dispatch: `id` must be numeric, `method` must be a
///   JSON string, `payload` is extracted as a bounded value field. The
///   `ELIZA_MAX_PROTOCOL_LINE_BYTES` (16 MiB) cap prevents unbounded reads.
/// - Host-call allowlist: only `llama_hardware_info`, `llama_load_model`,
///   `llama_generate`, `llama_free`, `llama_cancel`, `eliza_tts_synthesize`,
///   `eliza_asr_transcribe`, `keep_awake_set`, `stream_emit`,
///   `bg_download_start`, `bg_download_status`, and `bg_download_cancel` are
///   dispatched by `handleHostCall`. All other method names return
///   `{"ok":false,"error":"..."}`.
/// - `http_fetch` (JSContext compat path): loopback/local-agent URLs are
///   rejected at `HTTPBridge.isLocalLoopback` before a URLRequest is created.
///   External fetches go through URLSession with the standard iOS ATS policy.
/// - `http_request` IPC (both paths): the path must begin with `/` and must not
///   contain `://`. Validated in `MobileAgentBridgePlugin.proxyHttpRequest` and
///   enforced by the Bun bridge contract at the agent layer.
/// - Filesystem (JSContext compat path): `FSBridge` does not restrict paths
///   beyond what the iOS app sandbox enforces. The agent bundle is signed and
///   staged inside the app bundle; paths visible to the JSContext are limited to
///   the app container by the OS.
/// - ABI version check: `load()` verifies the framework reports ABI version "3"
///   before accepting any other symbols. A version mismatch is a hard error.
final class FullBunEngineHost {
    static let shared = FullBunEngineHost()
    private static let expectedAbiVersion = "3"

    private typealias AbiVersionFn = @convention(c) () -> UnsafePointer<CChar>?
    private typealias LastErrorFn = @convention(c) () -> UnsafePointer<CChar>?
    private typealias HostCallbackFn = @convention(c) (
        UnsafePointer<CChar>?,
        UnsafePointer<CChar>?,
        Int32
    ) -> UnsafeMutablePointer<CChar>?
    private typealias SetHostCallbackFn = @convention(c) (HostCallbackFn?) -> Int32
    private typealias StartFn = @convention(c) (
        UnsafePointer<CChar>,
        UnsafePointer<CChar>,
        UnsafePointer<CChar>,
        UnsafePointer<CChar>
    ) -> Int32
    private typealias StopFn = @convention(c) () -> Int32
    private typealias IsRunningFn = @convention(c) () -> Int32
    private typealias CallFn = @convention(c) (
        UnsafePointer<CChar>,
        UnsafePointer<CChar>
    ) -> UnsafeMutablePointer<CChar>?
    private typealias FreeFn = @convention(c) (UnsafeMutableRawPointer?) -> Void

    private var loaded = false
#if !ELIZA_IOS_FULL_BUN_ENGINE && DEBUG
    private var handle: UnsafeMutableRawPointer?
#endif
    private var abiVersionFn: AbiVersionFn?
    private var lastErrorFn: LastErrorFn?
    private var setHostCallbackFn: SetHostCallbackFn?
    private var startFn: StartFn?
    private var stopFn: StopFn?
    private var isRunningFn: IsRunningFn?
    private var callFn: CallFn?
    private var freeFn: FreeFn?
    private var running = false

    /// Delivers one `agentStream*` event to the WebView. Set by the plugin so
    /// the `stream_emit` host-call (fired per token while `http_request_stream`
    /// is in flight) reaches `CAPPlugin.notifyListeners` (#12354). Nil until the
    /// plugin wires it; a stream emit with no sink is a no-op envelope.
    var streamEventSink: ((_ eventName: String, _ data: [String: Any]) -> Void)?

    private init() {}

    var isAvailable: Bool {
        do {
            try load()
            return true
        } catch {
            return false
        }
    }

    var abiVersion: String {
        guard let abi = abiVersionFn?() else { return "unknown" }
        return String(cString: abi)
    }

    var isRunning: Bool {
        do {
            try load()
            let engineRunning = isRunningFn?() == 1
            if !engineRunning { running = false }
            return engineRunning
        } catch {
            running = false
            return false
        }
    }

    func start(
        bundlePath: String,
        argv: [String],
        env: [String: String],
        appSupportDir: String
    ) throws {
        let startedAt = Date()
        NSLog("[FullBunEngineHost] start requested bundle=\(bundlePath) appSupport=\(appSupportDir) argv=\(argv) envKeys=\(env.keys.sorted())")
        try load()
        if running {
            if isRunningFn?() == 1 { return }
            running = false
        }
        guard let startFn else {
            throw makeError("ElizaBunEngine missing start symbol")
        }
        let argvJson = try encodeJSON(argv)
        let envJson = try encodeJSON(env)
        let code = bundlePath.withCString { bundlePtr in
            argvJson.withCString { argvPtr in
                envJson.withCString { envPtr in
                    appSupportDir.withCString { supportPtr in
                        startFn(bundlePtr, argvPtr, envPtr, supportPtr)
                    }
                }
            }
        }
        guard code == 0 else {
            let detail = lastError()
            let durationMs = Int(Date().timeIntervalSince(startedAt) * 1000)
            NSLog("[FullBunEngineHost] start failed code=\(code) durationMs=\(durationMs) detail=\(detail)")
            throw makeError(
                "ElizaBunEngine start failed with code \(code)" +
                    (detail.isEmpty ? "" : ": \(detail)")
            )
        }
        running = true
        let durationMs = Int(Date().timeIntervalSince(startedAt) * 1000)
        NSLog("[FullBunEngineHost] start succeeded abi=\(abiVersion) durationMs=\(durationMs)")
    }

    func stop() {
        _ = stopFn?()
        running = false
    }

    func call(method: String, payload: Any?) throws -> Any? {
        try load()
        guard let callFn else {
            throw makeError("ElizaBunEngine missing call symbol")
        }
        let previousError = lastError()
        let payloadJson = try encodeJSON(payload ?? NSNull())
        let resultPtr = method.withCString { methodPtr in
            payloadJson.withCString { payloadPtr in
                callFn(methodPtr, payloadPtr)
            }
        }
        guard let resultPtr else {
            NSLog("[FullBunEngineHost] call returned null method=\(method) lastError=\(lastError())")
            throw makeError("ElizaBunEngine call returned null for \(method)")
        }
        defer { freeFn?(UnsafeMutableRawPointer(resultPtr)) }
        let resultJson = String(cString: resultPtr)
        guard let data = resultJson.data(using: .utf8) else {
            throw makeError("ElizaBunEngine returned non-UTF8 payload")
        }
        let decoded = try JSONSerialization.jsonObject(with: data)
        if let dict = decoded as? [String: Any],
           let ok = dict["ok"] as? Bool,
           ok == false {
            let message = dict["error"] as? String ?? "unknown full Bun engine error"
            let currentError = lastError()
            let diagnostic = !currentError.isEmpty && currentError != message
                ? currentError
                : previousError
            let detail = diagnostic.isEmpty || diagnostic == message
                ? ""
                : " (engine error: \(diagnostic))"
            NSLog("[FullBunEngineHost] call failed method=\(method) error=\(message) diagnostic=\(diagnostic)")
            throw makeError("\(message)\(detail)")
        }
        if let dict = decoded as? [String: Any],
           let ok = dict["ok"] as? Bool,
           ok == true {
            return dict["result"] ?? NSNull()
        }
        return decoded
    }

    private func load() throws {
        if loaded { return }
        NSLog("[FullBunEngineHost] loading ElizaBunEngine")
#if ELIZA_IOS_FULL_BUN_ENGINE
        let loadedAbiVersionFn: AbiVersionFn = {
            eliza_bun_engine_abi_version()
        }
        let loadedLastErrorFn: LastErrorFn = {
            eliza_bun_engine_last_error()
        }
        let loadedSetHostCallbackFn: SetHostCallbackFn = { callback in
            eliza_bun_engine_set_host_callback(callback)
        }
        let loadedStartFn: StartFn = { bundlePath, argvJson, envJson, appSupportDir in
            eliza_bun_engine_start(bundlePath, argvJson, envJson, appSupportDir)
        }
        let loadedStopFn: StopFn = {
            eliza_bun_engine_stop()
        }
        let loadedIsRunningFn: IsRunningFn = {
            eliza_bun_engine_is_running()
        }
        let loadedCallFn: CallFn = { method, payload in
            eliza_bun_engine_call(method, payload)
        }
        let loadedFreeFn: FreeFn = { ptr in
            eliza_bun_engine_free(ptr)
        }
        try installLoadedEngineSymbols(
            abiVersionFn: loadedAbiVersionFn,
            lastErrorFn: loadedLastErrorFn,
            setHostCallbackFn: loadedSetHostCallbackFn,
            startFn: loadedStartFn,
            stopFn: loadedStopFn,
            isRunningFn: loadedIsRunningFn,
            callFn: loadedCallFn,
            freeFn: loadedFreeFn
        )
#elseif DEBUG
        let binaryPath = try locateFrameworkBinary()
        guard let openedHandle = dlopen(binaryPath, RTLD_NOW | RTLD_LOCAL) else {
            throw makeError(String(cString: dlerror()))
        }
        do {
            let loadedAbiVersionFn: AbiVersionFn = try symbol(
                "eliza_bun_engine_abi_version",
                in: openedHandle
            )
            let loadedLastErrorFn: LastErrorFn = try symbol(
                "eliza_bun_engine_last_error",
                in: openedHandle
            )
            let loadedSetHostCallbackFn: SetHostCallbackFn = try symbol(
                "eliza_bun_engine_set_host_callback",
                in: openedHandle
            )
            let loadedStartFn: StartFn = try symbol("eliza_bun_engine_start", in: openedHandle)
            let loadedStopFn: StopFn = try symbol("eliza_bun_engine_stop", in: openedHandle)
            let loadedIsRunningFn: IsRunningFn = try symbol(
                "eliza_bun_engine_is_running",
                in: openedHandle
            )
            let loadedCallFn: CallFn = try symbol("eliza_bun_engine_call", in: openedHandle)
            let loadedFreeFn: FreeFn = try symbol("eliza_bun_engine_free", in: openedHandle)
            try installLoadedEngineSymbols(
                abiVersionFn: loadedAbiVersionFn,
                lastErrorFn: loadedLastErrorFn,
                setHostCallbackFn: loadedSetHostCallbackFn,
                startFn: loadedStartFn,
                stopFn: loadedStopFn,
                isRunningFn: loadedIsRunningFn,
                callFn: loadedCallFn,
                freeFn: loadedFreeFn
            )
            self.handle = openedHandle
        } catch {
            _ = dlclose(openedHandle)
            throw error
        }
#else
        throw makeError(
            "ElizaBunEngine direct-link symbols are not compiled into this release build"
        )
#endif
    }

    private func installLoadedEngineSymbols(
        abiVersionFn loadedAbiVersionFn: AbiVersionFn,
        lastErrorFn loadedLastErrorFn: LastErrorFn,
        setHostCallbackFn loadedSetHostCallbackFn: SetHostCallbackFn,
        startFn loadedStartFn: StartFn,
        stopFn loadedStopFn: StopFn,
        isRunningFn loadedIsRunningFn: IsRunningFn,
        callFn loadedCallFn: CallFn,
        freeFn loadedFreeFn: FreeFn
    ) throws {
        guard let abiPointer = loadedAbiVersionFn() else {
            throw makeError("ElizaBunEngine ABI version returned null")
        }
        let loadedAbiVersion = String(cString: abiPointer)
        guard loadedAbiVersion == Self.expectedAbiVersion else {
            throw makeError(
                "ElizaBunEngine ABI mismatch: expected \(Self.expectedAbiVersion), got \(loadedAbiVersion)"
            )
        }
        let callbackCode = loadedSetHostCallbackFn(fullBunHostCallCallback)
        guard callbackCode == 0 else {
            throw makeError("ElizaBunEngine failed to install host callback: \(callbackCode)")
        }

        self.abiVersionFn = loadedAbiVersionFn
        self.lastErrorFn = loadedLastErrorFn
        self.setHostCallbackFn = loadedSetHostCallbackFn
        self.startFn = loadedStartFn
        self.stopFn = loadedStopFn
        self.isRunningFn = loadedIsRunningFn
        self.callFn = loadedCallFn
        self.freeFn = loadedFreeFn
        self.loaded = true
        NSLog("[FullBunEngineHost] loaded ElizaBunEngine abi=\(loadedAbiVersion)")
    }

#if !ELIZA_IOS_FULL_BUN_ENGINE && DEBUG
    private func locateFrameworkBinary() throws -> String {
        let relative = "ElizaBunEngine.framework/ElizaBunEngine"
        let candidates = [
            Bundle.main.privateFrameworksURL?.appendingPathComponent(relative).path,
            Bundle.main.bundleURL.appendingPathComponent("Frameworks").appendingPathComponent(relative).path,
            Bundle.main.url(
                forResource: "ElizaBunEngine",
                withExtension: nil,
                subdirectory: "Frameworks/ElizaBunEngine.framework"
            )?.path,
        ].compactMap { $0 }
        for candidate in candidates where FileManager.default.fileExists(atPath: candidate) {
            return candidate
        }
        throw makeError("ElizaBunEngine.framework is not embedded in the app bundle")
    }

    private func symbol<T>(_ name: String, in handle: UnsafeMutableRawPointer) throws -> T {
        guard let pointer = dlsym(handle, name) else {
            throw makeError("ElizaBunEngine missing symbol \(name)")
        }
        return unsafeBitCast(pointer, to: T.self)
    }
#endif

    private func encodeJSON(_ value: Any) throws -> String {
        let data = try JSONSerialization.data(withJSONObject: value)
        return String(data: data, encoding: .utf8) ?? "{}"
    }

    private func lastError() -> String {
        guard let pointer = lastErrorFn?() else { return "" }
        return String(cString: pointer)
    }

    private func makeError(_ message: String) -> NSError {
        NSError(
            domain: "ElizaBunEngine",
            code: -1,
            userInfo: [NSLocalizedDescriptionKey: message]
        )
    }

    fileprivate func handleHostCall(
        method: String,
        payloadJson: String,
        timeoutMs: Int32
    ) -> String {
        _ = timeoutMs
        NSLog("[FullBunEngineHost] host call method=\(method) payloadBytes=\(payloadJson.lengthOfBytes(using: .utf8)) timeoutMs=\(timeoutMs)")
        do {
            let payload = try decodeHostPayload(payloadJson)
            switch method {
            case "llama_hardware_info":
                return encodeHostEnvelope(ok: true, result: LlamaBridgeImpl.shared.hardwareInfo().asDict())
            case "llama_load_model":
                return try handleLoadModel(payload)
            case "llama_generate":
                return try handleGenerate(payload)
            case "llama_free":
                return handleFree(payload)
            case "llama_cancel":
                return handleCancel(payload)
            case "eliza_tts_synthesize":
                return handleTtsSynthesize(payload)
            case "eliza_asr_transcribe":
                return handleAsrTranscribe(payload)
            case "keep_awake_set":
                // Hold the iOS idle timer open while an in-process model
                // download is active so auto-lock cannot suspend the runtime
                // mid-transfer (#11841). Reference-counted natively.
                let enabled = boolValue(payload, "enabled") ?? false
                KeepAwakeBridge.shared.setEnabled(enabled)
                return encodeHostEnvelope(ok: true, result: ["enabled": NSNumber(value: enabled)])
            case "stream_emit":
                // One chat-stream event (response head / token chunk / complete)
                // fired by the bridge's `http_request_stream` handler while it
                // runs. Forward it to the WebView as the matching `agentStream*`
                // Capacitor event so the TS adapter reconstructs a live
                // ReadableStream (#12354).
                return handleStreamEmit(payload)
            case "bg_download_start":
                // Route the large on-device model file through a native
                // background URLSession so the ~5 GB transfer survives the app
                // backgrounding / the device locking (#11841). The downloader
                // polls `bg_download_status` for progress + completion.
                guard let id = stringValue(payload, "id"), !id.isEmpty,
                      let url = stringValue(payload, "url"), !url.isEmpty,
                      let destPath = stringValue(payload, "destPath"), !destPath.isEmpty else {
                    return encodeHostEnvelope(
                        ok: false,
                        error: "bg_download_start requires id, url, and destPath"
                    )
                }
                let headers = stringMapValue(payload, "headers") ?? [:]
                let total = int64Value(payload, "expectedTotalBytes") ?? 0
                return encodeHostEnvelope(ok: true, result: BackgroundDownloadBridge.shared.start(
                    id: id,
                    urlString: url,
                    headers: headers,
                    destPath: destPath,
                    expectedTotalBytes: total
                ))
            case "bg_download_status":
                guard let id = stringValue(payload, "id"), !id.isEmpty else {
                    return encodeHostEnvelope(ok: false, error: "bg_download_status requires id")
                }
                return encodeHostEnvelope(ok: true, result: BackgroundDownloadBridge.shared.status(id: id))
            case "bg_download_cancel":
                guard let id = stringValue(payload, "id"), !id.isEmpty else {
                    return encodeHostEnvelope(ok: false, error: "bg_download_cancel requires id")
                }
                return encodeHostEnvelope(ok: true, result: BackgroundDownloadBridge.shared.cancel(id: id))
            default:
                return encodeHostEnvelope(
                    ok: false,
                    error: "Unknown native host call method: \(method)"
                )
            }
        } catch {
            return encodeHostEnvelope(ok: false, error: error.localizedDescription)
        }
    }

    private func handleLoadModel(_ payload: [String: Any]) throws -> String {
        guard let path = stringValue(payload, "path") ?? stringValue(payload, "modelPath"),
              !path.isEmpty else {
            return encodeHostEnvelope(ok: false, error: "llama_load_model requires path")
        }
        let contextSize = uint32Value(payload, "context_size")
            ?? uint32Value(payload, "contextSize")
            ?? 4096
        let useGPU = boolValue(payload, "use_gpu")
            ?? boolValue(payload, "useGpu")
            ?? true
        let threads = int32Value(payload, "threads")
            ?? int32Value(payload, "maxThreads")
        let result = LlamaBridgeImpl.shared.loadModel(
            path: path,
            contextSize: contextSize,
            useGPU: useGPU,
            threads: threads
        )
        if let error = result.error {
            return encodeHostEnvelope(ok: false, error: error)
        }
        guard let contextId = result.contextId else {
            return encodeHostEnvelope(ok: false, error: "llama_load_model returned no context_id")
        }
        return encodeHostEnvelope(ok: true, result: [
            "context_id": NSNumber(value: contextId),
            "contextId": NSNumber(value: contextId),
            "modelPath": path,
            "contextSize": NSNumber(value: contextSize),
            "useGpu": NSNumber(value: useGPU),
        ])
    }

    private func handleGenerate(_ payload: [String: Any]) throws -> String {
        guard let contextId = int64Value(payload, "context_id")
            ?? int64Value(payload, "contextId") else {
            return encodeHostEnvelope(ok: false, error: "llama_generate requires context_id")
        }
        guard let prompt = stringValue(payload, "prompt"), !prompt.isEmpty else {
            return encodeHostEnvelope(ok: false, error: "llama_generate requires prompt")
        }
        let maxTokens = int32Value(payload, "max_tokens")
            ?? int32Value(payload, "maxTokens")
            ?? 256
        let temperature = floatValue(payload, "temperature") ?? 0.7
        let topP = floatValue(payload, "top_p") ?? floatValue(payload, "topP") ?? 0.95
        let topK = int32Value(payload, "top_k") ?? int32Value(payload, "topK") ?? 40
        let stopSequences = stringArrayValue(payload, "stop")
            ?? stringArrayValue(payload, "stopSequences")
            ?? []

        let generate = {
            LlamaBridgeImpl.shared.generate(
                contextId: contextId,
                prompt: prompt,
                maxTokens: maxTokens,
                temperature: temperature,
                topP: topP,
                topK: topK,
                stopSequences: stopSequences
            )
        }
        let result: LlamaGenerateResult
        if let queue = LlamaBridgeImpl.shared.workQueue(for: contextId) {
            result = queue.sync(execute: generate)
        } else {
            result = generate()
        }
        if let error = result.error {
            return encodeHostEnvelope(ok: false, error: error)
        }
        return encodeHostEnvelope(ok: true, result: [
            "text": result.text,
            "promptTokens": NSNumber(value: result.promptTokens),
            "outputTokens": NSNumber(value: result.outputTokens),
            "durationMs": NSNumber(value: result.durationMs),
        ])
    }

    private func handleFree(_ payload: [String: Any]) -> String {
        guard let contextId = int64Value(payload, "context_id")
            ?? int64Value(payload, "contextId") else {
            return encodeHostEnvelope(ok: true, result: ["freed": false])
        }
        LlamaBridgeImpl.shared.free(contextId: contextId)
        return encodeHostEnvelope(ok: true, result: [
            "freed": true,
            "context_id": NSNumber(value: contextId),
        ])
    }

    private func handleCancel(_ payload: [String: Any]) -> String {
        guard let contextId = int64Value(payload, "context_id")
            ?? int64Value(payload, "contextId") else {
            return encodeHostEnvelope(ok: true, result: ["cancelled": false])
        }
        LlamaBridgeImpl.shared.cancel(contextId: contextId)
        return encodeHostEnvelope(ok: true, result: [
            "cancelled": true,
            "context_id": NSNumber(value: contextId),
        ])
    }

    /// Translate one `stream_emit` frame into the matching `agentStream*`
    /// Capacitor event and hand it to the WebView. The frame `kind` mirrors the
    /// Android streaming contract so `createNativeStreamingResponse` consumes it
    /// unmodified: `response` → `agentStreamResponse`, `chunk` →
    /// `agentStreamChunk`, `complete` → `agentStreamComplete` (#12354).
    private func handleStreamEmit(_ payload: [String: Any]) -> String {
        guard let streamId = stringValue(payload, "streamId"), !streamId.isEmpty else {
            return encodeHostEnvelope(ok: false, error: "stream_emit requires streamId")
        }
        guard let kind = stringValue(payload, "kind") else {
            return encodeHostEnvelope(ok: false, error: "stream_emit requires kind")
        }
        guard let sink = streamEventSink else {
            // No WebView listener is wired (e.g. a smoke harness). Acknowledge so
            // the bridge keeps streaming rather than tearing the turn down.
            return encodeHostEnvelope(ok: true, result: ["delivered": false])
        }

        switch kind {
        case "response":
            var data: [String: Any] = [
                "streamId": streamId,
                "status": NSNumber(value: intValue(payload, "status") ?? 200),
            ]
            if let statusText = stringValue(payload, "statusText") {
                data["statusText"] = statusText
            }
            if let headers = stringMapValue(payload, "headers") {
                data["headers"] = headers
            }
            sink("agentStreamResponse", data)
        case "chunk":
            guard let dataBase64 = stringValue(payload, "dataBase64") else {
                return encodeHostEnvelope(ok: false, error: "stream_emit chunk requires dataBase64")
            }
            sink("agentStreamChunk", ["streamId": streamId, "dataBase64": dataBase64])
        case "complete":
            var data: [String: Any] = ["streamId": streamId]
            if let error = stringValue(payload, "error") {
                data["error"] = error
            }
            sink("agentStreamComplete", data)
        default:
            return encodeHostEnvelope(ok: false, error: "stream_emit unknown kind: \(kind)")
        }
        return encodeHostEnvelope(ok: true, result: ["delivered": true])
    }

    private func handleTtsSynthesize(_ payload: [String: Any]) -> String {
        guard let bundleDir = stringValue(payload, "bundleDir")
            ?? stringValue(payload, "bundle_dir"),
            !bundleDir.isEmpty else {
            return encodeHostEnvelope(ok: false, error: "eliza_tts_synthesize requires bundleDir")
        }
        guard let text = stringValue(payload, "text"), !text.isEmpty else {
            return encodeHostEnvelope(ok: false, error: "eliza_tts_synthesize requires text")
        }
        let speakerPresetId = stringValue(payload, "speakerPresetId")
            ?? stringValue(payload, "speaker_preset_id")
            ?? stringValue(payload, "voice")
            ?? stringValue(payload, "voiceId")
        let maxSamples = intValue(payload, "maxSamples")
            ?? intValue(payload, "max_samples")
            ?? 24_000 * 60
        let result = LlamaBridgeImpl.shared.synthesizeSpeech(
            bundleDir: bundleDir,
            text: text,
            speakerPresetId: speakerPresetId,
            maxSamples: maxSamples
        )
        if let error = result.error {
            return encodeHostEnvelope(ok: false, error: error)
        }
        var payload: [String: Any] = [
            "contentType": result.contentType,
            "sampleRate": NSNumber(value: result.sampleRate),
            "samples": NSNumber(value: result.samples),
            "durationMs": NSNumber(value: result.durationMs),
        ]
        if let audioFilePath = result.audioFilePath, !audioFilePath.isEmpty {
            payload["audioFilePath"] = audioFilePath
        } else {
            payload["audioBase64"] = result.audioBase64
        }
        return encodeHostEnvelope(ok: true, result: payload)
    }

    /// Wire format: `pcm` is mono fp32 audio in [-1, 1] carried as a JSON number
    /// array (no base64). `bridge.ts` encodes the same way. `sampleRate` is the
    /// source rate in Hz; the inference slice resamples internally as needed.
    private func handleAsrTranscribe(_ payload: [String: Any]) -> String {
        guard let bundleDir = stringValue(payload, "bundleDir")
            ?? stringValue(payload, "bundle_dir"),
            !bundleDir.isEmpty else {
            return encodeHostEnvelope(ok: false, error: "eliza_asr_transcribe requires bundleDir")
        }
        guard let pcm = floatArrayValue(payload, "pcm"), !pcm.isEmpty else {
            return encodeHostEnvelope(ok: false, error: "eliza_asr_transcribe requires pcm")
        }
        let sampleRate = intValue(payload, "sampleRate")
            ?? intValue(payload, "sample_rate")
            ?? 16_000
        let result = LlamaBridgeImpl.shared.transcribeSpeech(
            bundleDir: bundleDir,
            pcm: pcm,
            sampleRate: sampleRate
        )
        if let error = result.error {
            return encodeHostEnvelope(ok: false, error: error)
        }
        return encodeHostEnvelope(ok: true, result: [
            "text": result.text,
            "durationMs": NSNumber(value: result.durationMs),
        ])
    }

    private func decodeHostPayload(_ json: String) throws -> [String: Any] {
        guard let data = json.data(using: .utf8) else { return [:] }
        let value = try JSONSerialization.jsonObject(with: data)
        return value as? [String: Any] ?? [:]
    }

    private func encodeHostEnvelope(
        ok: Bool,
        result: Any? = nil,
        error: String? = nil
    ) -> String {
        var object: [String: Any] = ["ok": ok]
        if let result {
            object["result"] = result
        } else if ok {
            object["result"] = NSNull()
        }
        if let error {
            object["error"] = error
        }
        guard JSONSerialization.isValidJSONObject(object),
              let data = try? JSONSerialization.data(withJSONObject: object),
              let json = String(data: data, encoding: .utf8) else {
            let fallback = (error ?? "Failed to encode native host response")
                .replacingOccurrences(of: "\"", with: "\\\"")
            return "{\"ok\":false,\"error\":\"\(fallback)\"}"
        }
        return json
    }

    private func stringValue(_ payload: [String: Any], _ key: String) -> String? {
        payload[key] as? String
    }

    private func boolValue(_ payload: [String: Any], _ key: String) -> Bool? {
        if let value = payload[key] as? Bool { return value }
        if let value = payload[key] as? NSNumber { return value.boolValue }
        if let value = payload[key] as? String {
            if value == "true" || value == "1" { return true }
            if value == "false" || value == "0" { return false }
        }
        return nil
    }

    private func int32Value(_ payload: [String: Any], _ key: String) -> Int32? {
        if let value = payload[key] as? NSNumber { return value.int32Value }
        if let value = payload[key] as? String, let parsed = Int32(value) { return parsed }
        return nil
    }

    private func intValue(_ payload: [String: Any], _ key: String) -> Int? {
        if let value = payload[key] as? NSNumber { return value.intValue }
        if let value = payload[key] as? String, let parsed = Int(value) { return parsed }
        return nil
    }

    private func int64Value(_ payload: [String: Any], _ key: String) -> Int64? {
        if let value = payload[key] as? NSNumber { return value.int64Value }
        if let value = payload[key] as? String, let parsed = Int64(value) { return parsed }
        return nil
    }

    private func uint32Value(_ payload: [String: Any], _ key: String) -> UInt32? {
        if let value = payload[key] as? NSNumber { return value.uint32Value }
        if let value = payload[key] as? String, let parsed = UInt32(value) { return parsed }
        return nil
    }

    private func floatValue(_ payload: [String: Any], _ key: String) -> Float? {
        if let value = payload[key] as? NSNumber { return value.floatValue }
        if let value = payload[key] as? String, let parsed = Float(value) { return parsed }
        return nil
    }

    private func stringMapValue(_ payload: [String: Any], _ key: String) -> [String: String]? {
        guard let raw = payload[key] as? [String: Any] else { return nil }
        var out: [String: String] = [:]
        for (mapKey, value) in raw {
            if let string = value as? String {
                out[mapKey] = string
            } else if let number = value as? NSNumber {
                out[mapKey] = number.stringValue
            }
        }
        return out
    }

    private func stringArrayValue(_ payload: [String: Any], _ key: String) -> [String]? {
        if let values = payload[key] as? [String] { return values }
        if let values = payload[key] as? [Any] {
            return values.compactMap { $0 as? String }
        }
        return nil
    }

    private func floatArrayValue(_ payload: [String: Any], _ key: String) -> [Float]? {
        if let values = payload[key] as? [NSNumber] {
            return values.map { $0.floatValue }
        }
        if let values = payload[key] as? [Any] {
            return values.compactMap { ($0 as? NSNumber)?.floatValue }
        }
        return nil
    }
}