/*
 * Copyright 2020 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 androidx.compose.ui.input.key

import androidx.compose.ui.ExperimentalComposeUiApi
import androidx.compose.ui.Modifier
import androidx.compose.ui.node.DelegatableNode
import androidx.compose.ui.node.modifierElementOf

/**
 * Implement this interface to create a [Modifier.Node] that can intercept hardware Key events.
 *
 * The event is routed to the focused item. Before reaching the focused item, [onPreKeyEvent]() is
 * called for parents of the focused item. If the parents don't consume the event, [onPreKeyEvent]()
 * is called for the focused item. If the event is still not consumed, [onKeyEvent]() is called on
 * the focused item's parents.
 */
@ExperimentalComposeUiApi
interface KeyInputModifierNode : DelegatableNode {

    /**
     * This function is called when a [KeyEvent] is received by this node during the upward
     * pass. While implementing this callback, return true to stop propagation of this event. If you
     * return false, the key event will be sent to this [KeyInputModifierNode]'s parent.
     */
    fun onKeyEvent(event: KeyEvent): Boolean

    /**
     * This function is called when a [KeyEvent] is received by this node during the
     * downward pass. It gives ancestors of a focused component the chance to intercept an event.
     * Return true to stop propagation of this event. If you return false, the event will be sent
     * to this [KeyInputModifierNode]'s child. If none of the children consume the event,
     * it will be sent back up to the root using the [onKeyEvent] function.
     */
    fun onPreKeyEvent(event: KeyEvent): Boolean
}

@ExperimentalComposeUiApi
internal class KeyInputInputModifierNodeImpl(
    var onEvent: ((KeyEvent) -> Boolean)?,
    var onPreEvent: ((KeyEvent) -> Boolean)?
) : KeyInputModifierNode, Modifier.Node() {
    override fun onKeyEvent(event: KeyEvent): Boolean = this.onEvent?.invoke(event) ?: false
    override fun onPreKeyEvent(event: KeyEvent): Boolean = this.onPreEvent?.invoke(event) ?: false
}

/**
 * Adding this [modifier][Modifier] to the [modifier][Modifier] parameter of a component will
 * allow it to intercept hardware key events when it (or one of its children) is focused.
 *
 * @param onKeyEvent This callback is invoked when the user interacts with the hardware keyboard.
 * While implementing this callback, return true to stop propagation of this event. If you return
 * false, the key event will be sent to this [onKeyEvent]'s parent.
 *
 * @sample androidx.compose.ui.samples.KeyEventSample
 */
@OptIn(ExperimentalComposeUiApi::class)
@Suppress("ModifierInspectorInfo") // b/251831790.
fun Modifier.onKeyEvent(onKeyEvent: (KeyEvent) -> Boolean): Modifier = this.then(
    modifierElementOf(
        key = onKeyEvent,
        create = { KeyInputInputModifierNodeImpl(onEvent = onKeyEvent, onPreEvent = null) },
        update = { it.onEvent = onKeyEvent },
        definitions = {
            name = "onKeyEvent"
            properties["onKeyEvent"] = onKeyEvent
        }
    )
)

/**
 * Adding this [modifier][Modifier] to the [modifier][Modifier] parameter of a component will
 * allow it to intercept hardware key events when it (or one of its children) is focused.
 *
 * @param onPreviewKeyEvent This callback is invoked when the user interacts with the hardware
 * keyboard. It gives ancestors of a focused component the chance to intercept a [KeyEvent].
 * Return true to stop propagation of this event. If you return false, the key event will be sent
 * to this [onPreviewKeyEvent]'s child. If none of the children consume the event, it will be
 * sent back up to the root [KeyInputModifierNode] using the onKeyEvent callback.
 *
 * @sample androidx.compose.ui.samples.KeyEventSample
 */
@OptIn(ExperimentalComposeUiApi::class)
@Suppress("ModifierInspectorInfo") // b/251831790.
fun Modifier.onPreviewKeyEvent(onPreviewKeyEvent: (KeyEvent) -> Boolean): Modifier = this.then(
    modifierElementOf(
        key = onPreviewKeyEvent,
        create = { KeyInputInputModifierNodeImpl(onEvent = null, onPreEvent = onPreviewKeyEvent) },
        update = { it.onPreEvent = onPreviewKeyEvent },
        definitions = {
            name = "onPreviewKeyEvent"
            properties["onPreviewKeyEvent"] = onPreviewKeyEvent
        }
    )
)