FitnessDroid/app/src/main/java/eu/brassepc/fitnessdroid/data/RestTimer.kt

package eu.brassepc.fitnessdroid.data

import android.content.Context
import android.media.RingtoneManager
import android.os.VibrationEffect
import android.os.VibratorManager
import kotlinx.coroutines.CoroutineScope
import kotlinx.coroutines.Job
import kotlinx.coroutines.delay
import kotlinx.coroutines.flow.MutableStateFlow
import kotlinx.coroutines.flow.StateFlow
import kotlinx.coroutines.flow.first
import kotlinx.coroutines.launch

data class RestState(
    val totalSeconds: Int,
    val endsAtEpochMs: Long,
    val secondsLeft: Int,
    val finished: Boolean = false,
)

/**
 * Vilotimern. Räknar mot en absolut sluttid (överlever att appen pausas)
 * och larmar enligt inställningarna när tiden är ute.
 */
class RestTimerController(
    private val context: Context,
    private val settingsStore: SettingsStore,
    private val scope: CoroutineScope,
) {
    private val _state = MutableStateFlow<RestState?>(null)
    val state: StateFlow<RestState?> = _state

    private var ticker: Job? = null

    fun start(seconds: Int? = null) {
        scope.launch {
            val settings = settingsStore.settings.first()
            val total = seconds ?: settings.defaultRestSeconds
            _state.value = RestState(
                totalSeconds = total,
                endsAtEpochMs = System.currentTimeMillis() + total * 1000L,
                secondsLeft = total,
            )
            startTicker()
        }
    }

    fun adjust(deltaSeconds: Int) {
        val current = _state.value ?: return
        if (current.finished) return
        _state.value = current.copy(
            endsAtEpochMs = (current.endsAtEpochMs + deltaSeconds * 1000L)
                .coerceAtLeast(System.currentTimeMillis()),
            totalSeconds = (current.totalSeconds + deltaSeconds).coerceAtLeast(5),
        )
    }

    fun dismiss() {
        ticker?.cancel()
        _state.value = null
    }

    private fun startTicker() {
        ticker?.cancel()
        ticker = scope.launch {
            while (true) {
                val current = _state.value ?: return@launch
                val left = (((current.endsAtEpochMs - System.currentTimeMillis()) + 999) / 1000)
                    .coerceAtLeast(0).toInt()
                if (left != current.secondsLeft) {
                    _state.value = current.copy(secondsLeft = left)
                }
                if (left <= 0) {
                    _state.value = _state.value?.copy(secondsLeft = 0, finished = true)
                    alert()
                    // Låt "klart"-läget synas en stund, försvinn sedan självmant.
                    delay(8_000)
                    if (_state.value?.finished == true) _state.value = null
                    return@launch
                }
                delay(250)
            }
        }
    }

    private suspend fun alert() {
        when (settingsStore.settings.first().restAlert) {
            RestAlert.SOUND -> runCatching {
                val uri = RingtoneManager.getDefaultUri(RingtoneManager.TYPE_NOTIFICATION)
                RingtoneManager.getRingtone(context, uri)?.play()
            }
            RestAlert.VIBRATE -> runCatching {
                val vm = context.getSystemService(Context.VIBRATOR_MANAGER_SERVICE) as VibratorManager
                vm.defaultVibrator.vibrate(
                    VibrationEffect.createWaveform(longArrayOf(0, 350, 150, 350, 150, 500), -1)
                )
            }
            RestAlert.VISUAL, RestAlert.NONE -> Unit
        }
    }
}