package cash.z.ecc.android.ui.settings

import androidx.lifecycle.ViewModel
import cash.z.ecc.android.di.DependenciesHolder
import cash.z.ecc.android.ext.Const
import cash.z.ecc.android.lockbox.LockBox
import cash.z.ecc.android.sdk.Synchronizer
import cash.z.ecc.android.util.twig
import kotlinx.coroutines.flow.MutableStateFlow
import kotlin.properties.Delegates.observable
import kotlin.reflect.KProperty

class SettingsViewModel : ViewModel() {

    private val synchronizer: Synchronizer = DependenciesHolder.synchronizer

    private val prefs: LockBox = DependenciesHolder.prefs

    lateinit var uiModels: MutableStateFlow<UiModel>

    private lateinit var initialServer: UiModel

    var pendingHost by observable("", ::onUpdateModel)
    var pendingPortText by observable("", ::onUpdateModel)

    private fun getHost(): String {
        return prefs[Const.Pref.SERVER_HOST] ?: Const.Default.Server.HOST
    }

    private fun getPort(): Int {
        return prefs[Const.Pref.SERVER_PORT] ?: Const.Default.Server.PORT
    }

    fun init() {
        initialServer = UiModel(getHost(), getPort().toString())
        uiModels = MutableStateFlow(initialServer)
    }

    suspend fun resetServer() {
        UiModel(
            Const.Default.Server.HOST,
            Const.Default.Server.PORT.toString()
        ).let { default ->
            uiModels.value = default
            submit()
        }
    }

    suspend fun submit() {
        // Note: this only takes effect after the app is relaunched
        val host = uiModels.value.host
        val port = uiModels.value.portInt
        prefs[Const.Pref.SERVER_HOST] = host
        prefs[Const.Pref.SERVER_PORT] = port
        uiModels.value = uiModels.value.copy(changeError = null, complete = true)
    }

    private fun onUpdateModel(kProperty: KProperty<*>, old: String, new: String) {
        val pendingPort = pendingPortText.toIntOrNull() ?: -1
        uiModels.value = UiModel(
            pendingHost,
            pendingPortText,
            pendingHost != initialServer.host || pendingPortText != initialServer.portText,
            if (!pendingHost.isValidHost()) "Please enter a valid host name or IP" else null,
            if (pendingPort >= 65535) "Please enter a valid port number below 65535" else null
        ).also {
            twig("updated model with $it")
        }
    }

    data class UiModel(
        val host: String = "",
        val portText: String = "",
        val submitEnabled: Boolean = false,
        val hostErrorMessage: String? = null,
        val portErrorMessage: String? = null,
        val changeError: Throwable? = null,
        val complete: Boolean = false
    ) {
        val portInt get() = portText.toIntOrNull() ?: -1
        val hasError get() = hostErrorMessage != null || portErrorMessage != null
    }

    // we can beef this up later if we want to but this is enough for now
    private fun String.isValidHost(): Boolean {
        return !contains("://")
    }
}