/*

* Copyright 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

*

* https://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.

*/

@file:Suppress("unused")

package com.example.compose.snippets.phases

import androidx.compose.foundation.Canvas

import androidx.compose.foundation.Image

import androidx.compose.foundation.layout.Box

import androidx.compose.foundation.layout.fillMaxWidth

import androidx.compose.foundation.layout.offset

import androidx.compose.foundation.layout.padding

import androidx.compose.foundation.lazy.LazyColumn

import androidx.compose.foundation.lazy.rememberLazyListState

import androidx.compose.material3.Text

import androidx.compose.runtime.Composable

import androidx.compose.runtime.MutableState

import androidx.compose.runtime.getValue

import androidx.compose.runtime.mutableStateOf

import androidx.compose.runtime.remember

import androidx.compose.runtime.setValue

import androidx.compose.ui.Modifier

import androidx.compose.ui.graphics.Color

import androidx.compose.ui.layout.onSizeChanged

import androidx.compose.ui.platform.LocalDensity

import androidx.compose.ui.res.painterResource

import androidx.compose.ui.unit.Dp

import androidx.compose.ui.unit.IntOffset

import androidx.compose.ui.unit.dp

@Composable

private fun StateReadWithoutPropertyDelegate() {

// [START android_compose_phases_state_read_without_property_delegate]

// State read without property delegate.

val paddingState: MutableState<Dp> = remember { mutableStateOf(8.dp) }

Text(

text = "Hello",

modifier = Modifier.padding(paddingState.value)

)

// [END android_compose_phases_state_read_without_property_delegate]

}

@Suppress("CanBeVal")

@Composable

private fun StateReadWithPropertyDelegate() {

// [START android_compose_phases_state_read_with_property_delegate]

// State read with property delegate.

var padding: Dp by remember { mutableStateOf(8.dp) }

Text(

text = "Hello",

modifier = Modifier.padding(padding)

)

// [END android_compose_phases_state_read_with_property_delegate]

}

@Suppress("CanBeVal")

@Composable

private fun CompositionSnippet() {

// [START android_compose_phases_composition]

var padding by remember { mutableStateOf(8.dp) }

Text(

text = "Hello",

// The `padding` state is read in the composition phase

// when the modifier is constructed.

// Changes in `padding` will invoke recomposition.

modifier = Modifier.padding(padding)

)

// [END android_compose_phases_composition]

}

@Suppress("CanBeVal")

@Composable

private fun LayoutSnippet() {

// [START android_compose_phases_layout]

var offsetX by remember { mutableStateOf(8.dp) }

Text(

text = "Hello",

modifier = Modifier.offset {

// The `offsetX` state is read in the placement step

// of the layout phase when the offset is calculated.

// Changes in `offsetX` restart the layout.

IntOffset(offsetX.roundToPx(), 0)

}

)

// [END android_compose_phases_layout]

}

@Suppress("CanBeVal")

@Composable

private fun DrawingSnippet(modifier: Modifier) {

// [START android_compose_phases_drawing]

var color by remember { mutableStateOf(Color.Red) }

Canvas(modifier = modifier) {

// The `color` state is read in the drawing phase

// when the canvas is rendered.

// Changes in `color` restart the drawing.

drawRect(color)

}

// [END android_compose_phases_drawing]

}

@Composable

private fun OptimizeStateReadsBefore() {

// [START android_compose_phases_optimize_state_reads_before]

Box {

val listState = rememberLazyListState()

Image(

// [START_EXCLUDE]

painterResource(id = android.R.drawable.star_on),

contentDescription = null,

// [END_EXCLUDE]

// Non-optimal implementation!

Modifier.offset(

with(LocalDensity.current) {

// State read of firstVisibleItemScrollOffset in composition

(listState.firstVisibleItemScrollOffset / 2).toDp()

}

)

)

LazyColumn(state = listState) {

// [START_EXCLUDE]

// [END_EXCLUDE]

}

}

// [END android_compose_phases_optimize_state_reads_before]

}

@Composable

private fun OptimizeStateReadsAfter() {

// [START android_compose_phases_optimize_state_reads_after]

Box {

val listState = rememberLazyListState()

Image(

// [START_EXCLUDE]

painterResource(id = android.R.drawable.star_on),

contentDescription = null,

// [END_EXCLUDE]

Modifier.offset {

// State read of firstVisibleItemScrollOffset in Layout

IntOffset(x = 0, y = listState.firstVisibleItemScrollOffset / 2)

}

)

LazyColumn(state = listState) {

// [START_EXCLUDE]

// [END_EXCLUDE]

}

}

// [END android_compose_phases_optimize_state_reads_after]

}

private object Loop {

@Suppress("ClassName")

object R {

object drawable {

const val rectangle = 1

}

}

@Composable

fun Loop() {

// [START android_compose_phases_loop]

Box {

var imageHeightPx by remember { mutableStateOf(0) }

Image(

painter = painterResource(R.drawable.rectangle),

contentDescription = "I'm above the text",

modifier = Modifier

.fillMaxWidth()

.onSizeChanged { size ->

// Don't do this

imageHeightPx = size.height

}

)

Text(

text = "I'm below the image",

modifier = Modifier.padding(

top = with(LocalDensity.current) { imageHeightPx.toDp() }

)

)

}

// [END android_compose_phases_loop]

}

}