/*
 * 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.deviceentry.ui.view

import android.content.Context
import android.util.AttributeSet
import android.view.MotionEvent
import android.view.View
import com.android.systemui.deviceentry.ui.viewmodel.DeviceEntryUdfpsAccessibilityOverlayViewModel
import com.android.systemui.deviceentry.ui.viewmodel.UdfpsAccessibilityOverlayViewModel

/** Overlay to handle under-fingerprint sensor accessibility events. */
class UdfpsAccessibilityOverlay(context: Context?, attrs: AttributeSet? = null) :
    View(context, attrs) {
    lateinit var udfpsAccessibilityOverlayViewModel: UdfpsAccessibilityOverlayViewModel
    private var mLastHoverEnterEventTime: Long = -1
    private val tapDurationThreshold: Long = 600

    init {
        accessibilityLiveRegion = ACCESSIBILITY_LIVE_REGION_ASSERTIVE
        importantForAccessibility = IMPORTANT_FOR_ACCESSIBILITY_NO
        isClickable = false
    }

    /**
     * The UDFPS accessibility overlay should only react to motion events when the user's finger is
     * in contact with the view, and should be unfocusable with a null content description whenever
     * the user's finger is no longer in contact with the view.
     *
     * On ACTION_HOVER_ENTER (tap or drag gesture on view) or ACTION_HOVER_MOVE (user is performing
     * long drag gesture across view), we mark the view IMPORTANT_FOR_ACCESSIBILITY_YES to enable
     * the accessibilityLiveRegion, and update the content description of the view to the
     * appropriate UDFPS guidance message.
     *
     * On ACTION_HOVER_EXIT, (user's finger is lifted from view, or performs drag gesture out of
     * bounds of the view), we mark the view IMPORTANT_FOR_ACCESSIBILITY_NO to disable the
     * accessibilityLiveRegion, and clear the content description. This is to disable the
     * accessibilityLiveRegion and linear navigation to the overlay, ensure the overlay does not
     * retain a stale content description, and allow Talkback to send the same UDFPS guidance
     * message again in sequence on the next motion event if needed.
     *
     * If the ACTION_HOVER_EXIT event was part a tap gesture (vs. a drag gesture), we add a delay in
     * order to prevent clearing the content description before Talkback can process the
     * accessibility event generated by the accessibilityLiveRegion.
     */
    override fun dispatchGenericMotionEvent(event: MotionEvent): Boolean {
        if (!this::udfpsAccessibilityOverlayViewModel.isInitialized) {
            // ViewModel is not ready, skip processing event
            return true
        }

        if (event.action == MotionEvent.ACTION_HOVER_ENTER) {
            mLastHoverEnterEventTime = event.eventTime
        }

        if (
            event.action == MotionEvent.ACTION_HOVER_ENTER ||
                event.action == MotionEvent.ACTION_HOVER_MOVE
        ) {
            // Prepend the lockscreen content description for single taps on lock screen
            val includeLockscreenContentDescription =
                (event.eventTime - mLastHoverEnterEventTime) < 200
            val udfpsHint =
                if (
                    udfpsAccessibilityOverlayViewModel
                        is DeviceEntryUdfpsAccessibilityOverlayViewModel
                ) {
                    udfpsAccessibilityOverlayViewModel
                        .getUdfpsDirectionalFeedbackOnHoverEnterOrMove(
                            event,
                            includeLockscreenContentDescription,
                        )
                } else {
                    udfpsAccessibilityOverlayViewModel
                        .getUdfpsDirectionalFeedbackOnHoverEnterOrMove(event)
                }

            udfpsHint?.let {
                contentDescription = null
                importantForAccessibility = IMPORTANT_FOR_ACCESSIBILITY_YES
                contentDescription = it
            }
        } else if (event.action == MotionEvent.ACTION_HOVER_EXIT) {
            val delay: Long =
                if (event.eventTime - mLastHoverEnterEventTime < tapDurationThreshold) {
                    600
                } else {
                    0
                }
            postDelayed(
                {
                    importantForAccessibility = IMPORTANT_FOR_ACCESSIBILITY_NO
                    contentDescription = null
                },
                delay,
            )
        }
        return true
    }
}