package agzam.vyatsu.ui.settings

import agzam.vyatsu.BuildConfig
import agzam.vyatsu.update.UpdateState
import androidx.compose.foundation.clickable
import androidx.compose.foundation.layout.Column
import androidx.compose.foundation.layout.Row
import androidx.compose.foundation.layout.WindowInsets
import androidx.compose.foundation.layout.fillMaxWidth
import androidx.compose.foundation.layout.heightIn
import androidx.compose.foundation.layout.padding
import androidx.compose.foundation.layout.statusBars
import androidx.compose.foundation.layout.windowInsetsPadding
import androidx.compose.foundation.lazy.LazyColumn
import androidx.compose.material3.HorizontalDivider
import androidx.compose.material3.MaterialTheme
import androidx.compose.material3.Switch
import androidx.compose.material3.Text
import androidx.compose.runtime.Composable
import androidx.compose.runtime.collectAsState
import androidx.compose.runtime.getValue
import androidx.compose.ui.Alignment
import androidx.compose.ui.Modifier
import androidx.compose.ui.unit.dp

@Composable
fun SettingsScreen(viewModel: UpdateViewModel) {
    val autoEnabled by viewModel.autoEnabled.collectAsState()
    val updateState by viewModel.updateState.collectAsState()

    LazyColumn(
        Modifier
            .fillMaxWidth()
            .windowInsetsPadding(WindowInsets.statusBars)
    ) {
        item { SectionHeader("Обновления") }
        item {
            SettingsItem(
                title = "Автоматические обновления",
                subtitle = "Проверять и устанавливать новые версии при запуске",
                trailing = {
                    Switch(
                        checked = autoEnabled,
                        onCheckedChange = { viewModel.setAutoEnabled(it) }
                    )
                }
            )
            SettingsDivider()
        }
        item {
            SettingsItem(
                title = "Проверить наличие обновлений",
                subtitle = updateStatusText(updateState, autoEnabled),
                onClick = { viewModel.checkNow() }
            )
            SettingsDivider()
        }
        if (autoEnabled && (updateState is UpdateState.Available || updateState is UpdateState.ReadyToInstall)) {
            item {
                SettingsItem(
                    title = "Установить обновление",
                    subtitle = installHint(updateState, viewModel),
                    onClick = {
                        when (updateState) {
                            is UpdateState.Available -> viewModel.downloadAndInstall()
                            is UpdateState.ReadyToInstall -> viewModel.installDownloadedApk()
                            else -> {}
                        }
                    }
                )
                SettingsDivider()
            }
        }

        item { SectionHeader("О приложении") }
        item {
            SettingsItem(
                title = "Версия",
                trailing = {
                    Text(
                        BuildConfig.VERSION_NAME,
                        style = MaterialTheme.typography.bodyMedium,
                        color = MaterialTheme.colorScheme.onSurfaceVariant
                    )
                }
            )
            SettingsDivider()
        }
    }
}

private fun updateStatusText(state: UpdateState, autoEnabled: Boolean): String = when (state) {
    is UpdateState.Idle -> "Проверить сейчас"
    is UpdateState.Checking -> "Проверка…"
    is UpdateState.UpToDate -> "Установлена последняя версия"
    is UpdateState.Available ->
        if (autoEnabled) "Доступна версия ${state.version}"
        else "Доступна версия ${state.version} — включите автообновления для установки"
    is UpdateState.Downloading -> "Скачивание: ${state.progress?.let { "$it%" } ?: "…"}"
    is UpdateState.ReadyToInstall -> "Обновление скачано, нажмите для установки"
    is UpdateState.Failed -> "Ошибка: ${state.message}"
}

private fun installHint(state: UpdateState, viewModel: UpdateViewModel): String = when {
    state is UpdateState.ReadyToInstall && !viewModel.canRequestInstalls() ->
        "Разрешите установку приложений из этого источника"
    else -> "Нажмите, чтобы продолжить"
}

@Composable
private fun SectionHeader(title: String) {
    Text(
        title,
        style = MaterialTheme.typography.titleSmall,
        color = MaterialTheme.colorScheme.onSurfaceVariant,
        modifier = Modifier.padding(horizontal = 16.dp, vertical = 8.dp)
    )
}

@Composable
private fun SettingsItem(
    title: String,
    subtitle: String? = null,
    trailing: (@Composable () -> Unit)? = null,
    onClick: (() -> Unit)? = null
) {
    Row(
        Modifier
            .fillMaxWidth()
            .heightIn(min = 48.dp)
            .then(if (onClick != null) Modifier.clickable(onClick = onClick) else Modifier)
            .padding(horizontal = 16.dp, vertical = 12.dp),
        verticalAlignment = Alignment.CenterVertically
    ) {
        Column(Modifier.weight(1f)) {
            Text(title, style = MaterialTheme.typography.bodyLarge)
            if (subtitle != null) {
                Text(
                    subtitle,
                    style = MaterialTheme.typography.bodyMedium,
                    color = MaterialTheme.colorScheme.onSurfaceVariant
                )
            }
        }
        trailing?.invoke()
    }
}

@Composable
private fun SettingsDivider() {
    HorizontalDivider(Modifier.padding(horizontal = 16.dp))
}