/*
 * Copyright (C) 2023 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.systemui.mediaprojection.taskswitcher.ui.viewmodel

import android.app.ActivityManager.RunningTaskInfo
import android.util.Log
import androidx.annotation.VisibleForTesting
import com.android.systemui.dagger.qualifiers.Background
import com.android.systemui.mediaprojection.taskswitcher.domain.interactor.TaskSwitchInteractor
import com.android.systemui.mediaprojection.taskswitcher.domain.model.TaskSwitchState
import com.android.systemui.mediaprojection.taskswitcher.ui.model.TaskSwitcherNotificationUiState
import javax.inject.Inject
import kotlin.time.Duration.Companion.seconds
import kotlinx.coroutines.CoroutineDispatcher
import kotlinx.coroutines.delay
import kotlinx.coroutines.flow.Flow
import kotlinx.coroutines.flow.map
import kotlinx.coroutines.flow.transformLatest
import kotlinx.coroutines.withContext

class TaskSwitcherNotificationViewModel
@Inject
constructor(
    private val interactor: TaskSwitchInteractor,
    @Background private val backgroundDispatcher: CoroutineDispatcher,
) {

    val uiState: Flow<TaskSwitcherNotificationUiState> =
        interactor.taskSwitchChanges
            .map { taskSwitchChange ->
                Log.d(TAG, "taskSwitchChange: $taskSwitchChange")
                when (taskSwitchChange) {
                    is TaskSwitchState.TaskSwitched -> {
                        TaskSwitcherNotificationUiState.Showing(
                            projectedTask = taskSwitchChange.projectedTask,
                            foregroundTask = taskSwitchChange.foregroundTask,
                        )
                    }
                    is TaskSwitchState.NotProjectingTask,
                    is TaskSwitchState.TaskUnchanged -> {
                        TaskSwitcherNotificationUiState.NotShowing
                    }
                }
            }
            .transformLatest { uiState ->
                emit(uiState)
                if (uiState is TaskSwitcherNotificationUiState.Showing) {
                    delay(NOTIFICATION_MAX_SHOW_DURATION)
                    Log.d(TAG, "Auto hiding notification after $NOTIFICATION_MAX_SHOW_DURATION")
                    emit(TaskSwitcherNotificationUiState.NotShowing)
                }
            }

    suspend fun onSwitchTaskClicked(task: RunningTaskInfo) {
        interactor.switchProjectedTask(task)
    }

    suspend fun onGoBackToTaskClicked(task: RunningTaskInfo) =
        withContext(backgroundDispatcher) { interactor.goBackToTask(task) }

    companion object {
        @VisibleForTesting val NOTIFICATION_MAX_SHOW_DURATION = 5.seconds
        private const val TAG = "TaskSwitchNotifVM"
    }
}