/*
 * Copyright (C) 2024 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.keyguard.ui.viewmodel

import com.android.app.animation.Interpolators.EMPHASIZED
import com.android.systemui.common.ui.domain.interactor.ConfigurationInteractor
import com.android.systemui.dagger.SysUISingleton
import com.android.systemui.keyguard.shared.model.Edge
import com.android.systemui.keyguard.shared.model.KeyguardState.DREAMING
import com.android.systemui.keyguard.shared.model.KeyguardState.GLANCEABLE_HUB
import com.android.systemui.keyguard.ui.KeyguardTransitionAnimationFlow
import com.android.systemui.keyguard.ui.transitions.DeviceEntryIconTransition
import com.android.systemui.res.R
import com.android.systemui.scene.shared.model.Scenes
import javax.inject.Inject
import kotlin.time.Duration.Companion.milliseconds
import kotlin.time.Duration.Companion.seconds
import kotlinx.coroutines.ExperimentalCoroutinesApi
import kotlinx.coroutines.flow.Flow
import kotlinx.coroutines.flow.flatMapLatest
import kotlinx.coroutines.flow.map

@OptIn(ExperimentalCoroutinesApi::class)
@SysUISingleton
class DreamingToGlanceableHubTransitionViewModel
@Inject
constructor(
    animationFlow: KeyguardTransitionAnimationFlow,
    configurationInteractor: ConfigurationInteractor,
) : DeviceEntryIconTransition {
    private val transitionAnimation =
        animationFlow
            .setup(
                duration = TO_GLANCEABLE_HUB_DURATION,
                edge = Edge.create(from = DREAMING, to = Scenes.Communal),
            )
            .setupWithoutSceneContainer(
                edge = Edge.create(from = DREAMING, to = GLANCEABLE_HUB),
            )

    val dreamOverlayTranslationX: Flow<Float> =
        configurationInteractor
            .dimensionPixelSize(R.dimen.dreaming_to_hub_transition_dream_overlay_translation_x)
            .flatMapLatest { translatePx ->
                transitionAnimation.sharedFlow(
                    duration = TO_GLANCEABLE_HUB_DURATION,
                    onStep = { value -> value * translatePx },
                    interpolator = EMPHASIZED,
                    onCancel = { 0f },
                    name = "DREAMING->GLANCEABLE_HUB: overlayTranslationX",
                )
            }

    // Keep the dream visible while the hub swipes in over the dream.
    val dreamAlpha: Flow<Float> = transitionAnimation.immediatelyTransitionTo(1f)

    val dreamOverlayAlpha: Flow<Float> =
        transitionAnimation.sharedFlow(
            duration = 167.milliseconds,
            onStep = { 1f - it },
            name = "DREAMING->GLANCEABLE_HUB: dreamOverlayAlpha",
        )

    // Show UMO once the transition starts.
    val showUmo: Flow<Boolean> =
        transitionAnimation
            .sharedFlow(
                duration = TO_GLANCEABLE_HUB_DURATION,
                onStep = { it },
                onCancel = { 0f },
                onFinish = { 1f },
            )
            .map { step -> step != 0f }

    override val deviceEntryParentViewAlpha: Flow<Float> =
        transitionAnimation.sharedFlow(
            startTime = 167.milliseconds,
            duration = 167.milliseconds,
            onStep = { it },
            onCancel = { 0f },
            onFinish = { 1f },
        )

    private companion object {
        val TO_GLANCEABLE_HUB_DURATION = 1.seconds
    }
}