package com.novoyuuparosk.iperf3gui

import io.flutter.embedding.engine.plugins.FlutterPlugin
import io.flutter.plugin.common.MethodChannel

/**
 * Kotlin binding layer for native iperf3 via JNI.
 *
 * This class loads the native library (libiperf3jni.so) and exposes
 * iperf3 functionality to Flutter via MethodChannel callbacks.
 *
 * iperf3 runs natively inside the app process — no Process.start() needed,
 * no SELinux restrictions. Output is streamed live to the Flutter UI via
 * the IperfCallback interface.
 */
object IperfRunner : FlutterPlugin {

    private var channel: MethodChannel? = null

    init {
        // Load native library at class initialization
        try {
            android.util.Log.i("IperfRunner", "Loading native library...")
            System.loadLibrary("iperf3jni")
            android.util.Log.i("IperfRunner", "Native library loaded successfully")
        } catch (e: UnsatisfiedLinkError) {
            android.util.Log.e("IperfRunner", "Failed to load native library: ${e.message}")
            e.printStackTrace()
        }
    }

    override fun onAttachedToEngine(binding: FlutterPlugin.FlutterPluginBinding) {
        channel = MethodChannel(binding.binaryMessenger, "com.novoyuuparosk.iperf3gui/iperf")
        channel?.setMethodCallHandler { call, result ->
            when (call.method) {
                "runIperf" -> {
                    val args = call.argument<List<String>>("args")?.toTypedArray()
                    if (args != null) {
                        runIperfLive(args, object : IperfCallback {
                            override fun onOutput(line: String) {
                                channel?.invokeMethod("onOutput", mapOf("output" to line))
                            }
                            override fun onError(error: String) {
                                channel?.invokeMethod("onError", mapOf("error" to error))
                            }
                            override fun onComplete() {
                                channel?.invokeMethod("onComplete", emptyMap<String, Any>())
                            }
                        })
                        result.success(null)
                    } else {
                        result.error("INVALID_ARGS", "args must be a String array", null)
                    }
                }
                "stopIperf" -> {
                    forceStopIperfTest(object : IperfCallback {
                        override fun onOutput(line: String) {
                            channel?.invokeMethod("onOutput", mapOf("output" to line))
                        }
                        override fun onError(error: String) {
                            channel?.invokeMethod("onError", mapOf("error" to error))
                        }
                        override fun onComplete() {
                            channel?.invokeMethod("onComplete", emptyMap<String, Any>())
                        }
                    })
                    result.success(null)
                }
                "isTestRunning" -> {
                    result.success(isTestRunning())
                }
                else -> {
                    result.notImplemented()
                }
            }
        }
    }

    override fun onDetachedFromEngine(binding: FlutterPlugin.FlutterPluginBinding) {
        channel = null
    }

    // ─────────────────────────────────────────────────────────────────
    // Native method bindings
    // ─────────────────────────────────────────────────────────────────

    /**
     * Start an iperf3 test with the given arguments.
     * This calls the native C function via JNI.
     */
    external fun runIperfLive(arguments: Array<String>, callback: IperfCallback)

    /**
     * Gracefully stop a running iperf3 test.
     */
    external fun forceStopIperfTest(callback: IperfCallback)

    /**
     * Check if an iperf3 test is currently running.
     * @return true if a test is in progress, false otherwise
     */
    external fun isTestRunning(): Boolean

    /**
     * Callback interface for iperf3 test output.
     *
     * Used by the native layer to stream test results back to Flutter
     * in real-time.
     */
    interface IperfCallback {
        /** Called with each line of iperf3 output (stdout/stderr) */
        fun onOutput(line: String)

        /** Called when an error occurs */
        fun onError(error: String)

        /** Called when the test completes (success or failure) */
        fun onComplete()
    }
}