/*
 * Copyright (C) 2022 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 */

package com.android.wallpaper.picker.undo.ui.viewmodel

import com.android.wallpaper.R
import com.android.wallpaper.module.logging.UserEventLogger
import com.android.wallpaper.picker.common.button.ui.viewmodel.ButtonStyle
import com.android.wallpaper.picker.common.button.ui.viewmodel.ButtonViewModel
import com.android.wallpaper.picker.common.dialog.ui.viewmodel.DialogViewModel
import com.android.wallpaper.picker.common.icon.ui.viewmodel.Icon
import com.android.wallpaper.picker.common.text.ui.viewmodel.Text
import com.android.wallpaper.picker.undo.domain.interactor.UndoInteractor
import kotlinx.coroutines.flow.Flow
import kotlinx.coroutines.flow.MutableStateFlow
import kotlinx.coroutines.flow.asStateFlow

/** Models the UI state of the undo system. */
class UndoViewModel(
    private val interactor: UndoInteractor,
    private val logger: UserEventLogger,
) {
    /** Whether the "revert" button should be visible. */
    val isRevertButtonVisible: Flow<Boolean> = interactor.isUndoable
    private val _dialog = MutableStateFlow<DialogViewModel?>(null)
    /**
     * A view-model of the undo confirmation dialog that should be shown, or `null` when no dialog
     * should be shown.
     */
    val dialog: Flow<DialogViewModel?> = _dialog.asStateFlow()

    /** Notifies that the "revert" button has been clicked by the user. */
    fun onRevertButtonClicked() {
        _dialog.value =
            DialogViewModel(
                icon =
                    Icon.Resource(
                        res = R.drawable.ic_device_reset,
                        contentDescription = null,
                    ),
                headline = Text.Resource(R.string.reset_confirmation_dialog_title),
                message = Text.Resource(R.string.reset_confirmation_dialog_message),
                buttons =
                    listOf(
                        ButtonViewModel(
                            text = Text.Resource(R.string.cancel),
                            style = ButtonStyle.Secondary,
                        ),
                        ButtonViewModel(
                            text = Text.Resource(R.string.reset),
                            style = ButtonStyle.Primary,
                            onClicked = {
                                interactor.revertAll()
                                logger.logResetApplied()
                                _dialog.value = null
                            },
                        ),
                    ),
                onDismissed = { _dialog.value = null },
            )
    }
}