car-interface-android/android/app/src/main/kotlin/com/wasp/cardash_launcher/SystemBridge.kt

package com.wasp.cardash_launcher

import android.app.Activity
import android.content.Intent
import android.content.IntentFilter
import android.media.AudioManager
import android.net.ConnectivityManager
import android.net.NetworkCapabilities
import android.os.BatteryManager
import android.util.Log
import android.view.KeyEvent
import android.view.WindowManager
import io.flutter.plugin.common.BinaryMessenger
import io.flutter.plugin.common.MethodCall
import io.flutter.plugin.common.MethodChannel

/** Battery, Wi-Fi and media-volume bridge. */
class SystemBridge(private val activity: Activity) : MethodChannel.MethodCallHandler {

    companion object {
        const val CHANNEL = "com.wasp.cardash_launcher/system"
        private const val VOLUME_TAG = "CarDashVolume"
    }

    private var channel: MethodChannel? = null
    private var lastVolumeLog: String? = null
    private val syu = SyuVolumeBridge(activity.applicationContext)

    fun attach(messenger: BinaryMessenger) {
        syu.start()
        channel = MethodChannel(messenger, CHANNEL).also { it.setMethodCallHandler(this) }
    }

    fun dispose() {
        syu.dispose()
        channel?.setMethodCallHandler(null)
        channel = null
    }

    override fun onMethodCall(call: MethodCall, result: MethodChannel.Result) {
        when (call.method) {
            "getStatus" -> result.success(readStatus())
            "getVolume" -> result.success(readVolume())
            "isMusicPlaying" -> result.success(isMusicPlaying())
            "setKeepScreenOn" -> {
                val enabled = call.argument<Boolean>("enabled")
                if (enabled == null) {
                    result.error("bad_arguments", "An enabled flag is required.", null)
                    return
                }
                setKeepScreenOn(enabled)
                result.success(true)
            }
            "mediaKey" -> {
                val action = call.argument<String>("action")
                if (action == null) {
                    result.error("bad_arguments", "A media key action is required.", null)
                    return
                }
                result.success(sendMediaKey(action))
            }
            "setVolume" -> {
                val index = call.argument<Int>("index")
                if (index == null) {
                    result.error("bad_arguments", "A volume index is required.", null)
                    return
                }
                result.success(setVolume(index))
            }
            else -> result.notImplemented()
        }
    }

    private fun readStatus(): Map<String, Any?> {
        val batteryIntent = activity.registerReceiver(
            null,
            IntentFilter(Intent.ACTION_BATTERY_CHANGED),
        )
        val level = batteryIntent?.getIntExtra(BatteryManager.EXTRA_LEVEL, -1) ?: -1
        val scale = batteryIntent?.getIntExtra(BatteryManager.EXTRA_SCALE, -1) ?: -1
        val percentage = if (level >= 0 && scale > 0) (level * 100f / scale).toInt() else 0
        val status = batteryIntent?.getIntExtra(BatteryManager.EXTRA_STATUS, -1) ?: -1
        val charging = status == BatteryManager.BATTERY_STATUS_CHARGING ||
            status == BatteryManager.BATTERY_STATUS_FULL

        val wifi = try {
            val connectivity = activity.getSystemService(ConnectivityManager::class.java)
            val network = connectivity?.activeNetwork
            val capabilities = network?.let { connectivity.getNetworkCapabilities(it) }
            capabilities?.hasTransport(NetworkCapabilities.TRANSPORT_WIFI) == true
        } catch (_: Throwable) {
            false
        }

        return mapOf(
            "batteryLevel" to percentage,
            "charging" to charging,
            "wifi" to wifi,
        )
    }

    private fun audioManager(): AudioManager =
        activity.getSystemService(AudioManager::class.java)

    private fun readVolume(): Map<String, Any?> {
        val audio = audioManager()
        // Until the MCU reports its current level we keep showing Android's
        // stream value; an absolute write based on the wrong scale could jump
        // the amplifier to full volume.
        val syuActive = syu.connected && syu.level != null
        val max = if (syuActive) {
            SyuVolumeBridge.MAX_LEVEL
        } else {
            audio.getStreamMaxVolume(AudioManager.STREAM_MUSIC)
        }
        val min = if (syuActive) 0 else minStreamVolume(audio, AudioManager.STREAM_MUSIC)
        val index = if (syuActive) {
            syu.level ?: 0
        } else {
            streamVolume(audio, AudioManager.STREAM_MUSIC)
        }
        val snapshot =
            mapOf(
                "index" to index,
                "max" to max,
                "min" to min,
                "fixed" to (if (syuActive) false else audio.isVolumeFixed),
                "source" to when {
                    syuActive -> "syu"
                    syu.connected -> "syu-wait"
                    else -> "system"
                },
                "vendor" to syu.status,
                "streams" to
                    mapOf(
                        "music" to streamVolume(audio, AudioManager.STREAM_MUSIC),
                        "voice" to streamVolume(audio, AudioManager.STREAM_VOICE_CALL),
                        "ring" to streamVolume(audio, AudioManager.STREAM_RING),
                        "alarm" to streamVolume(audio, AudioManager.STREAM_ALARM),
                        "notif" to streamVolume(audio, AudioManager.STREAM_NOTIFICATION),
                        "system" to streamVolume(audio, AudioManager.STREAM_SYSTEM),
                        "dtmf" to streamVolume(audio, AudioManager.STREAM_DTMF),
                        "access" to streamVolume(audio, AudioManager.STREAM_ACCESSIBILITY),
                    ),
            )
        val log = snapshot.toString()
        if (log != lastVolumeLog) {
            lastVolumeLog = log
            Log.i(VOLUME_TAG, "read $log")
        }
        return snapshot
    }

    private fun streamVolume(audio: AudioManager, stream: Int): Int {
        return try {
            audio.getStreamVolume(stream)
        } catch (_: Throwable) {
            -1
        }
    }

    private fun minStreamVolume(audio: AudioManager, stream: Int): Int {
        return try {
            audio.getStreamMinVolume(stream)
        } catch (_: Throwable) {
            0
        }
    }

    private fun isMusicPlaying(): Boolean {
        return try {
            audioManager().isMusicActive
        } catch (_: Throwable) {
            false
        }
    }

    private fun setKeepScreenOn(enabled: Boolean) {
        activity.runOnUiThread {
            try {
                if (enabled) {
                    activity.window.addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON)
                } else {
                    activity.window.clearFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON)
                }
            } catch (_: Throwable) {
                // Window flags are best-effort.
            }
        }
    }

    private fun sendMediaKey(action: String): Boolean {
        val keyCode = when (action) {
            "play" -> KeyEvent.KEYCODE_MEDIA_PLAY
            "pause" -> KeyEvent.KEYCODE_MEDIA_PAUSE
            "playPause" -> KeyEvent.KEYCODE_MEDIA_PLAY_PAUSE
            else -> return false
        }
        return try {
            val audio = audioManager()
            audio.dispatchMediaKeyEvent(KeyEvent(KeyEvent.ACTION_DOWN, keyCode))
            audio.dispatchMediaKeyEvent(KeyEvent(KeyEvent.ACTION_UP, keyCode))
            true
        } catch (_: Throwable) {
            false
        }
    }

    private fun setVolume(index: Int): Boolean {
        // On FYT/Syu units the amplifier ignores Android's stream volume, so
        // hand the change to the MCU app first.
        if (syu.connected && syu.level != null) {
            val target = index.coerceIn(0, SyuVolumeBridge.MAX_LEVEL)
            if (syu.setLevel(target)) {
                Log.i(VOLUME_TAG, "set syu target=$target")
                return true
            }
        }
        return try {
            val audio = audioManager()
            // A fixed-volume policy means the car amplifier owns the level;
            // software volume changes are intentionally ignored by Android.
            if (audio.isVolumeFixed) {
                Log.i(VOLUME_TAG, "set $index rejected: fixed volume")
                return false
            }

            val max = audio.getStreamMaxVolume(AudioManager.STREAM_MUSIC)
            val target = index.coerceIn(0, max)
            val before = audio.getStreamVolume(AudioManager.STREAM_MUSIC)
            audio.setStreamVolume(AudioManager.STREAM_MUSIC, target, 0)
            var after = audio.getStreamVolume(AudioManager.STREAM_MUSIC)
            Log.i(VOLUME_TAG, "set target=$target before=$before after=$after max=$max")
            if (after == target) return true

            if (after == before) {
                // Some head units only route a volume change through their own
                // panel; asking Android to show it uses a different code path
                // than a silent write.
                audio.setStreamVolume(
                    AudioManager.STREAM_MUSIC,
                    target,
                    AudioManager.FLAG_SHOW_UI,
                )
                after = audio.getStreamVolume(AudioManager.STREAM_MUSIC)
                Log.i(VOLUME_TAG, "set with ui target=$target after=$after")
                if (after == target) return true
            }

            // Some head units ignore absolute volume writes but accept the
            // same relative steps as the hardware volume keys.
            val result = if (after == before) adjustTo(audio, target, after) else false
            Log.i(VOLUME_TAG, "relative fallback result=$result now=${streamVolume(audio, AudioManager.STREAM_MUSIC)}")
            result
        } catch (error: Throwable) {
            Log.i(VOLUME_TAG, "set $index failed: $error")
            false
        }
    }

    private fun adjustTo(audio: AudioManager, target: Int, start: Int): Boolean {
        var current = start
        var remainingSteps = audio.getStreamMaxVolume(AudioManager.STREAM_MUSIC) * 2 + 2
        while (current != target && remainingSteps-- > 0) {
            audio.adjustStreamVolume(
                AudioManager.STREAM_MUSIC,
                if (target > current) AudioManager.ADJUST_RAISE else AudioManager.ADJUST_LOWER,
                0,
            )
            val next = audio.getStreamVolume(AudioManager.STREAM_MUSIC)
            if (next == current) return false
            current = next
        }
        return current == target
    }
}