experimental chat example (#2148)

experimental/examples/chat-mpp/.gitignore

@@ -0,0 +1,2 @@
+local.properties
+.idea

experimental/examples/chat-mpp/README.md

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+# Chat example app
+
+## Run on Android:
+- connect device or emulator
+- `./gradlew installDebug`
+- open app
+
+## Run on Desktop jvm
+  `./gradlew run`
+
+## Run native on MacOS
+  `./gradlew runDebugExecutableMacosX64` (Works on Intel processors)
+
+## Run web assembly in browser
+  `./gradlew jsBrowserDevelopmentRun`
+
+## Run on iOS simulator
+  `./gradlew iosDeployIPhone8Debug`
+  `./gradlew iosDeployIPadDebug`
+
+## Run on iOS device
+- Read about iOS target in [falling-balls-mpp/README.md](../falling-balls-mpp/README.md)
+- `./gradlew iosDeployDeviceRelease`

experimental/examples/chat-mpp/build.gradle.kts

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+import org.jetbrains.compose.compose
+import org.jetbrains.compose.desktop.application.dsl.TargetFormat
+import org.jetbrains.kotlin.gradle.plugin.mpp.KotlinNativeTarget
+import org.jetbrains.kotlin.gradle.tasks.KotlinCompile
+import org.jetbrains.kotlin.gradle.targets.js.nodejs.NodeJsRootExtension
+import org.jetbrains.compose.experimental.dsl.IOSDevices
+
+plugins {
+    id("com.android.application")
+    kotlin("multiplatform")
+    id("org.jetbrains.compose")
+}
+
+version = "1.0-SNAPSHOT"
+
+repositories {
+    google()
+    mavenCentral()
+    maven("https://maven.pkg.jetbrains.space/public/p/compose/dev")
+}
+
+kotlin {
+    android()
+    jvm("desktop")
+    js(IR) {
+        browser()
+        binaries.executable()
+    }
+    macosX64 {
+        binaries {
+            executable {
+                entryPoint = "main"
+                freeCompilerArgs += listOf(
+                    "-linker-option", "-framework", "-linker-option", "Metal"
+                )
+            }
+        }
+    }
+    macosArm64 {
+        binaries {
+            executable {
+                entryPoint = "main"
+                freeCompilerArgs += listOf(
+                    "-linker-option", "-framework", "-linker-option", "Metal"
+                )
+            }
+        }
+    }
+    iosX64("uikitX64") {
+        binaries {
+            executable() {
+                entryPoint = "main"
+                freeCompilerArgs += listOf(
+                    "-linker-option", "-framework", "-linker-option", "Metal",
+                    "-linker-option", "-framework", "-linker-option", "CoreText",
+                    "-linker-option", "-framework", "-linker-option", "CoreGraphics"
+                )
+            }
+        }
+    }
+    iosArm64("uikitArm64") {
+         binaries {
+             executable() {
+                entryPoint = "main"
+                freeCompilerArgs += listOf(
+                    "-linker-option", "-framework", "-linker-option", "Metal",
+                    "-linker-option", "-framework", "-linker-option", "CoreText",
+                    "-linker-option", "-framework", "-linker-option", "CoreGraphics"
+                )
+            }
+        }
+    }
+
+    sourceSets {
+        val commonMain by getting {
+            dependencies {
+                implementation(compose.ui)
+                implementation(compose.foundation)
+                implementation(compose.material)
+                implementation(compose.runtime)
+                implementation("org.jetbrains.kotlinx:kotlinx-coroutines-core:1.6.3")
+            }
+        }
+
+        val commonTest by getting {
+            dependencies {
+                implementation(kotlin("test-common"))
+                implementation(kotlin("test-annotations-common"))
+            }
+        }
+
+        val androidMain by getting {
+            dependsOn(commonMain)
+            kotlin.srcDirs("src/jvmMain/kotlin")
+            dependencies {
+                api("androidx.appcompat:appcompat:1.4.1")
+                implementation("androidx.activity:activity-compose:1.4.0")
+            }
+        }
+
+        val desktopMain by getting {
+             dependencies {
+                implementation(compose.desktop.currentOs)
+             }
+        }
+
+        val jsMain by getting {
+            dependencies {
+                implementation(compose.web.core)
+            }
+        }
+
+        val nativeMain by creating {
+            dependsOn(commonMain)
+        }
+        val macosMain by creating {
+            dependsOn(nativeMain)
+        }
+        val macosX64Main by getting {
+            dependsOn(macosMain)
+        }
+        val macosArm64Main by getting {
+            dependsOn(macosMain)
+        }
+        val uikitMain by creating {
+            dependsOn(nativeMain)
+        }
+        val uikitX64Main by getting {
+            dependsOn(uikitMain)
+        }
+        val uikitArm64Main by getting {
+            dependsOn(uikitMain)
+        }
+    }
+}
+
+compose.desktop {
+    application {
+        mainClass = "Main_desktopKt"
+    }
+}
+
+compose.experimental {
+    web.application {}
+    uikit.application {
+        bundleIdPrefix = "org.jetbrains"
+        projectName = "Chat"
+        deployConfigurations {
+            simulator("IPhone8") {
+                //Usage: ./gradlew iosDeployIPhone8Debug
+                device = IOSDevices.IPHONE_8
+            }
+            simulator("IPad") {
+                //Usage: ./gradlew iosDeployIPadDebug
+                device = IOSDevices.IPAD_MINI_6th_Gen
+            }
+            connectedDevice("Device") {
+                //First need specify your teamId here, or in local.properties (compose.ios.teamId=***)
+                //teamId="***"
+                //Usage: ./gradlew iosDeployDeviceRelease
+            }
+        }
+    }
+}
+
+tasks.withType<KotlinCompile> {
+    kotlinOptions.jvmTarget = "11"
+}
+
+compose.desktop.nativeApplication {
+    targets(kotlin.targets.getByName("macosX64"))
+    distributions {
+        targetFormats(TargetFormat.Dmg)
+        packageName = "Chat"
+        packageVersion = "1.0.0"
+    }
+}
+
+// a temporary workaround for a bug in jsRun invocation - see https://youtrack.jetbrains.com/issue/KT-48273
+afterEvaluate {
+    rootProject.extensions.configure<NodeJsRootExtension> {
+        versions.webpackDevServer.version = "4.0.0"
+        versions.webpackCli.version = "4.9.0"
+        nodeVersion = "16.0.0"
+    }
+}
+
+// TODO: remove when https://youtrack.jetbrains.com/issue/KT-50778 fixed
+project.tasks.withType(org.jetbrains.kotlin.gradle.dsl.KotlinJsCompile::class.java).configureEach {
+    kotlinOptions.freeCompilerArgs += listOf(
+        "-Xir-dce-runtime-diagnostic=log"
+    )
+}
+
+android {
+    compileSdk = 31
+
+    defaultConfig {
+        minSdk = 21
+        targetSdk = 31
+    }
+
+    compileOptions {
+        sourceCompatibility = JavaVersion.VERSION_11
+        targetCompatibility = JavaVersion.VERSION_11
+    }
+
+    sourceSets {
+        named("main") {
+            manifest.srcFile("src/androidMain/AndroidManifest.xml")
+            res.srcDirs("src/androidMain/res", "src/commonMain/resources")
+        }
+    }
+}
+

experimental/examples/chat-mpp/gradle.properties

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+org.gradle.jvmargs=-Xmx3g
+kotlin.code.style=official
+kotlin.native.cacheKind=none
+kotlin.native.useEmbeddableCompilerJar=true
+kotlin.native.enableDependencyPropagation=false
+kotlin.mpp.enableGranularSourceSetsMetadata=true
+kotlin.native.binary.memoryModel=experimental
+compose.desktop.verbose=true
+android.useAndroidX=true
+compose.version=1.2.0-alpha01-dev725
+kotlin.version=1.6.21
+agp.version=7.0.4
+kotlin.js.webpack.major.version=4

experimental/examples/chat-mpp/gradle/wrapper/gradle-wrapper.properties

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+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-7.4.2-bin.zip
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists

experimental/examples/chat-mpp/gradlew

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+#!/usr/bin/env sh
+
+#
+# Copyright 2015 the original author or authors.
+#
+# 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.
+#
+
+##############################################################################
+##
+##  Gradle start up script for UN*X
+##
+##############################################################################
+
+# Attempt to set APP_HOME
+# Resolve links: $0 may be a link
+PRG="$0"
+# Need this for relative symlinks.
+while [ -h "$PRG" ] ; do
+    ls=`ls -ld "$PRG"`
+    link=`expr "$ls" : '.*-> \(.*\)$'`
+    if expr "$link" : '/.*' > /dev/null; then
+        PRG="$link"
+    else
+        PRG=`dirname "$PRG"`"/$link"
+    fi
+done
+SAVED="`pwd`"
+cd "`dirname \"$PRG\"`/" >/dev/null
+APP_HOME="`pwd -P`"
+cd "$SAVED" >/dev/null
+
+APP_NAME="Gradle"
+APP_BASE_NAME=`basename "$0"`
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Use the maximum available, or set MAX_FD != -1 to use that value.
+MAX_FD="maximum"
+
+warn () {
+    echo "$*"
+}
+
+die () {
+    echo
+    echo "$*"
+    echo
+    exit 1
+}
+
+# OS specific support (must be 'true' or 'false').
+cygwin=false
+msys=false
+darwin=false
+nonstop=false
+case "`uname`" in
+  CYGWIN* )
+    cygwin=true
+    ;;
+  Darwin* )
+    darwin=true
+    ;;
+  MINGW* )
+    msys=true
+    ;;
+  NONSTOP* )
+    nonstop=true
+    ;;
+esac
+
+CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
+
+
+# Determine the Java command to use to start the JVM.
+if [ -n "$JAVA_HOME" ] ; then
+    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+        # IBM's JDK on AIX uses strange locations for the executables
+        JAVACMD="$JAVA_HOME/jre/sh/java"
+    else
+        JAVACMD="$JAVA_HOME/bin/java"
+    fi
+    if [ ! -x "$JAVACMD" ] ; then
+        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+else
+    JAVACMD="java"
+    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+
+# Increase the maximum file descriptors if we can.
+if [ "$cygwin" = "false" -a "$darwin" = "false" -a "$nonstop" = "false" ] ; then
+    MAX_FD_LIMIT=`ulimit -H -n`
+    if [ $? -eq 0 ] ; then
+        if [ "$MAX_FD" = "maximum" -o "$MAX_FD" = "max" ] ; then
+            MAX_FD="$MAX_FD_LIMIT"
+        fi
+        ulimit -n $MAX_FD
+        if [ $? -ne 0 ] ; then
+            warn "Could not set maximum file descriptor limit: $MAX_FD"
+        fi
+    else
+        warn "Could not query maximum file descriptor limit: $MAX_FD_LIMIT"
+    fi
+fi
+
+# For Darwin, add options to specify how the application appears in the dock
+if $darwin; then
+    GRADLE_OPTS="$GRADLE_OPTS \"-Xdock:name=$APP_NAME\" \"-Xdock:icon=$APP_HOME/media/gradle.icns\""
+fi
+
+# For Cygwin or MSYS, switch paths to Windows format before running java
+if [ "$cygwin" = "true" -o "$msys" = "true" ] ; then
+    APP_HOME=`cygpath --path --mixed "$APP_HOME"`
+    CLASSPATH=`cygpath --path --mixed "$CLASSPATH"`
+
+    JAVACMD=`cygpath --unix "$JAVACMD"`
+
+    # We build the pattern for arguments to be converted via cygpath
+    ROOTDIRSRAW=`find -L / -maxdepth 1 -mindepth 1 -type d 2>/dev/null`
+    SEP=""
+    for dir in $ROOTDIRSRAW ; do
+        ROOTDIRS="$ROOTDIRS$SEP$dir"
+        SEP="|"
+    done
+    OURCYGPATTERN="(^($ROOTDIRS))"
+    # Add a user-defined pattern to the cygpath arguments
+    if [ "$GRADLE_CYGPATTERN" != "" ] ; then
+        OURCYGPATTERN="$OURCYGPATTERN|($GRADLE_CYGPATTERN)"
+    fi
+    # Now convert the arguments - kludge to limit ourselves to /bin/sh
+    i=0
+    for arg in "$@" ; do
+        CHECK=`echo "$arg"|egrep -c "$OURCYGPATTERN" -`
+        CHECK2=`echo "$arg"|egrep -c "^-"`                                 ### Determine if an option
+
+        if [ $CHECK -ne 0 ] && [ $CHECK2 -eq 0 ] ; then                    ### Added a condition
+            eval `echo args$i`=`cygpath --path --ignore --mixed "$arg"`
+        else
+            eval `echo args$i`="\"$arg\""
+        fi
+        i=`expr $i + 1`
+    done
+    case $i in
+        0) set -- ;;
+        1) set -- "$args0" ;;
+        2) set -- "$args0" "$args1" ;;
+        3) set -- "$args0" "$args1" "$args2" ;;
+        4) set -- "$args0" "$args1" "$args2" "$args3" ;;
+        5) set -- "$args0" "$args1" "$args2" "$args3" "$args4" ;;
+        6) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" ;;
+        7) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" ;;
+        8) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" ;;
+        9) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" "$args8" ;;
+    esac
+fi
+
+# Escape application args
+save () {
+    for i do printf %s\\n "$i" | sed "s/'/'\\\\''/g;1s/^/'/;\$s/\$/' \\\\/" ; done
+    echo " "
+}
+APP_ARGS=`save "$@"`
+
+# Collect all arguments for the java command, following the shell quoting and substitution rules
+eval set -- $DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS "\"-Dorg.gradle.appname=$APP_BASE_NAME\"" -classpath "\"$CLASSPATH\"" org.gradle.wrapper.GradleWrapperMain "$APP_ARGS"
+
+exec "$JAVACMD" "$@"

experimental/examples/chat-mpp/settings.gradle.kts

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+pluginManagement {
+    repositories {
+        gradlePluginPortal()
+        maven("https://maven.pkg.jetbrains.space/public/p/compose/dev")
+        google()
+    }
+
+    plugins {
+        val kotlinVersion = extra["kotlin.version"] as String
+        val agpVersion = extra["agp.version"] as String
+        val composeVersion = extra["compose.version"] as String
+
+        kotlin("jvm").version(kotlinVersion)
+        kotlin("multiplatform").version(kotlinVersion)
+        kotlin("android").version(kotlinVersion)
+        id("com.android.base").version(agpVersion)
+        id("com.android.application").version(agpVersion)
+        id("com.android.library").version(agpVersion)
+        id("org.jetbrains.compose").version(composeVersion)
+    }
+}
+
+rootProject.name = "chat-mpp"

experimental/examples/chat-mpp/src/androidMain/AndroidManifest.xml

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+<?xml version="1.0" encoding="utf-8"?>
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    package="org.jetbrains.chat">
+
+    <application
+        android:allowBackup="true"
+        android:label="@string/app_name"
+        android:supportsRtl="true"
+        android:theme="@style/Theme.AppCompat.Light.NoActionBar">
+        <activity
+            android:exported="true"
+            android:name="MainActivity"
+            android:label="@string/app_name">
+            <intent-filter>
+                <action android:name="android.intent.action.MAIN" />
+
+                <category android:name="android.intent.category.LAUNCHER" />
+            </intent-filter>
+        </activity>
+    </application>
+
+</manifest>

experimental/examples/chat-mpp/src/androidMain/kotlin/MainActivity.kt

@@ -0,0 +1,17 @@
+package org.jetbrains.chat
+
+import android.os.Bundle
+import androidx.activity.compose.setContent
+import androidx.appcompat.app.AppCompatActivity
+import java.io.File
+import java.io.FileOutputStream
+import ChatApp
+
+class MainActivity : AppCompatActivity() {
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+        setContent {
+            ChatApp()
+        }
+    }
+}

experimental/examples/chat-mpp/src/androidMain/kotlin/currentTime.android.kt

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+actual fun timestampMs(): Long {
+    return System.currentTimeMillis()
+}

experimental/examples/chat-mpp/src/androidMain/res/res/values/strings.xml

@@ -0,0 +1,3 @@
+<resources>
+    <string name="app_name">Chat app</string>
+</resources>

experimental/examples/chat-mpp/src/androidMain/res/values/strings.xml

@@ -0,0 +1,3 @@
+<resources>
+    <string name="app_name">Chat app</string>
+</resources>

experimental/examples/chat-mpp/src/commonMain/kotlin/ChatApp.kt

@@ -0,0 +1,62 @@
+import androidx.compose.foundation.layout.*
+import androidx.compose.material.*
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.*
+import androidx.compose.ui.Modifier
+import kotlinx.coroutines.delay
+
+val myUser = User("Me")
+val friends = listOf(User("Alex"), User("Lily"), User("Sam"))
+val friendMessages = listOf(
+    "Hi, have a nice day!",
+    "Nice to see you!",
+    "Multiline\ntext\nmessage"
+)
+
+@Composable
+fun ChatApp() {
+    val coroutineScope = rememberCoroutineScope()
+    val store = remember { coroutineScope.createStore() }
+    val state by store.stateFlow.collectAsState()
+
+    MaterialTheme {
+        Box(modifier = Modifier.fillMaxSize()) {
+            Scaffold(
+                topBar = {
+                    TopAppBar(
+                        title = { Text("Chat sample") }
+                    )
+                }
+            ) {
+                Column(
+                    modifier = Modifier.fillMaxSize()
+                ) {
+                    Box(Modifier.weight(1f)) {
+                        Messages(state.messages)
+                    }
+                    SendMessage { text ->
+                        store.send(
+                            Action.SendMessage(
+                                Message(myUser, timeMs = timestampMs(), text)
+                            )
+                        )
+                    }
+                }
+            }
+        }
+    }
+    LaunchedEffect(Unit) {
+        while (true) {
+            store.send(
+                Action.SendMessage(
+                    message = Message(
+                        user = friends.random(),
+                        timeMs = timestampMs(),
+                        text = friendMessages.random()
+                    )
+                )
+            )
+            delay(5000)
+        }
+    }
+}

experimental/examples/chat-mpp/src/commonMain/kotlin/Data.kt

@@ -0,0 +1,29 @@
+import androidx.compose.ui.graphics.Color
+import kotlin.random.Random
+
+data class Message private constructor(
+    val user: User,
+    val timeMs: Long,
+    val text: String,
+    val id: Long
+) {
+    constructor(
+        user: User,
+        timeMs: Long,
+        text: String
+    ) : this(
+        user = user,
+        timeMs = timeMs,
+        text = text,
+        id = Random.nextLong()
+    )
+}
+
+data class User(
+    val name: String,
+    val pictureColor: Color = Color(
+        red = Random.nextInt(0xff),
+        green = Random.nextInt(0xff),
+        blue = Random.nextInt(0xff)
+    ),
+)

experimental/examples/chat-mpp/src/commonMain/kotlin/Messages.kt

@@ -0,0 +1,125 @@
+import androidx.compose.foundation.Image
+import androidx.compose.foundation.background
+import androidx.compose.foundation.clickable
+import androidx.compose.foundation.layout.*
+import androidx.compose.foundation.lazy.LazyColumn
+import androidx.compose.foundation.lazy.items
+import androidx.compose.foundation.lazy.rememberLazyListState
+import androidx.compose.foundation.shape.CircleShape
+import androidx.compose.foundation.shape.RoundedCornerShape
+import androidx.compose.material.*
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.Favorite
+import androidx.compose.material.icons.outlined.Favorite
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.*
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.draw.clip
+import androidx.compose.ui.geometry.Size
+import androidx.compose.ui.graphics.Brush
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.graphics.drawscope.DrawScope
+import androidx.compose.ui.graphics.painter.Painter
+import androidx.compose.ui.layout.ContentScale
+import androidx.compose.ui.unit.dp
+
+@Composable
+internal inline fun Messages(messages: List<Message>) {
+    val listState = rememberLazyListState()
+    if (messages.isNotEmpty()) {
+        LaunchedEffect(messages.last()) {
+            listState.animateScrollToItem(messages.lastIndex, scrollOffset = 2)
+        }
+    }
+    LazyColumn(
+        modifier = Modifier.fillMaxSize(),
+        verticalArrangement = Arrangement.spacedBy(8.dp),
+        state = listState,
+    ) {
+        messages.forEach { message ->
+            item(key = message.id) {
+                ChatMessage(isMyMessage = message.user == myUser, message)
+            }
+        }
+//        items(messages, key = { it.id }) { message -> //TODO not working in JS
+//            ChatMessage(isMyMessage = message.user == myUser, message)
+//        }
+    }
+}
+
+@Composable
+private inline fun ChatMessage(isMyMessage: Boolean, message: Message) {
+    Box(modifier = Modifier.fillMaxWidth()) {
+        Surface(
+            modifier = Modifier.padding(4.dp)
+                .align(if (isMyMessage) Alignment.CenterStart else Alignment.CenterEnd),
+            shape = RoundedCornerShape(size = 20.dp),
+            elevation = 8.dp
+        ) {
+            Box(
+                Modifier.background(brush = Brush.horizontalGradient(listOf(Color(0xff8888ff), Color(0xffddddff))))
+                    .padding(10.dp),
+            ) {
+                Row(verticalAlignment = Alignment.Top) {
+                    if (isMyMessage) {
+                        UserPic(message.user)
+                        Spacer(Modifier.size(8.dp))
+                    }
+                    Column {
+                        Row(verticalAlignment = Alignment.Bottom) {
+                            Text(
+                                text = message.user.name,
+                                style = MaterialTheme.typography.h5
+                            )
+                            Spacer(Modifier.size(10.dp))
+                            Text(
+                                text = timeToString(message.timeMs),
+                                style = MaterialTheme.typography.h6
+                            )
+                        }
+                        Text(
+                            text = message.text
+                        )
+                    }
+                    if (!isMyMessage) {
+                        Spacer(Modifier.size(8.dp))
+                        UserPic(message.user)
+                    }
+                }
+            }
+        }
+        if (!isMyMessage) {
+            var liked by remember { mutableStateOf(false) }
+            Icon(
+                modifier = Modifier.align(Alignment.BottomEnd)
+                    .clickable {
+                        liked = !liked
+                    }
+                    .padding(4.dp),
+                imageVector = if (liked) Icons.Filled.Favorite else Icons.Outlined.Favorite,
+                contentDescription = "Like",
+                tint = if (liked) Color.Red else Color.Gray
+            )
+        }
+    }
+}
+
+@Composable
+private fun UserPic(user: User) {
+    val imageSize = 64f
+    Image(
+        modifier = Modifier
+            .size(imageSize.dp)
+            .clip(CircleShape),
+        contentScale = ContentScale.Crop,
+        painter = object : Painter() {
+            override val intrinsicSize: Size = Size(imageSize, imageSize)
+            override fun DrawScope.onDraw() {
+                drawRect(user.pictureColor, size = Size(imageSize * 4, imageSize * 4))
+            }
+        },
+        contentDescription = "User picture"
+    )
+}

experimental/examples/chat-mpp/src/commonMain/kotlin/Reducer.kt

@@ -0,0 +1,16 @@
+sealed interface Action {
+    data class SendMessage(val message: Message) : Action
+}
+
+data class State(
+    val messages: List<Message> = emptyList()
+)
+
+fun chatReducer(state: State, action: Action): State =
+    when (action) {
+        is Action.SendMessage -> {
+            state.copy(
+                messages = (state.messages + action.message).takeLast(100)
+            )
+        }
+    }

experimental/examples/chat-mpp/src/commonMain/kotlin/SendMessage.kt

@@ -0,0 +1,54 @@
+import androidx.compose.foundation.background
+import androidx.compose.foundation.clickable
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.padding
+import androidx.compose.material.Icon
+import androidx.compose.material.MaterialTheme
+import androidx.compose.material.Text
+import androidx.compose.material.TextField
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.Send
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.*
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.unit.dp
+
+@Composable
+internal fun SendMessage(sendMessage: (String) -> Unit) {
+    var inputText by remember { mutableStateOf("") }
+    TextField(
+        modifier = Modifier.fillMaxWidth()
+            .background(MaterialTheme.colors.background)
+            .padding(10.dp),
+        value = inputText,
+        placeholder = {
+            Text("type message here")
+        },
+        onValueChange = {
+            inputText = it
+        },
+        trailingIcon = {
+            if (inputText.isNotEmpty()) {
+                Row(
+                    modifier = Modifier
+                        .clickable {
+                            sendMessage(inputText)
+                            inputText = ""
+                        }
+                        .padding(10.dp),
+                    verticalAlignment = Alignment.CenterVertically,
+                ) {
+                    Icon(
+                        imageVector = Icons.Default.Send,
+                        contentDescription = "Send",
+                        tint = MaterialTheme.colors.primary
+                    )
+                    Text("Send")
+                }
+            }
+        }
+    )
+}

experimental/examples/chat-mpp/src/commonMain/kotlin/Store.kt

@@ -0,0 +1,35 @@
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.channels.Channel
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.consumeAsFlow
+import kotlinx.coroutines.launch
+
+interface Store {
+    fun send(action: Action)
+    val stateFlow: StateFlow<State>
+    val state get() = stateFlow.value
+}
+
+fun CoroutineScope.createStore(): Store {
+    val mutableStateFlow = MutableStateFlow(State())
+    val channel: Channel<Action> = Channel(Channel.UNLIMITED)
+
+    return object : Store {
+        init {
+            launch {
+                channel.consumeAsFlow().collect { action ->
+                    mutableStateFlow.value = chatReducer(mutableStateFlow.value, action)
+                }
+            }
+        }
+
+        override fun send(action: Action) {
+            launch {
+                channel.send(action)
+            }
+        }
+
+        override val stateFlow: StateFlow<State> = mutableStateFlow
+    }
+}

experimental/examples/chat-mpp/src/commonMain/kotlin/currentTime.common.kt

@@ -0,0 +1,22 @@
+fun timeToString(timestampMs: Long): String {
+    val seconds = timestampMs
+    val minutes = seconds / 1000 / 60
+    val hours = minutes / 24
+
+    val m = minutes % 60
+    val h = hours % 24
+
+    val mm = if (m < 10) {
+        "0$m"
+    } else {
+        m.toString()
+    }
+    val hh = if (h < 10) {
+        "0$h"
+    } else {
+        h.toString()
+    }
+    return "$hh:$mm"
+}
+
+expect fun timestampMs(): Long

experimental/examples/chat-mpp/src/desktopMain/kotlin/currentTime.desktop.kt

@@ -0,0 +1,3 @@
+actual fun timestampMs(): Long {
+    return System.currentTimeMillis()
+}

experimental/examples/chat-mpp/src/desktopMain/kotlin/main.desktop.kt

@@ -0,0 +1,20 @@
+import androidx.compose.desktop.ui.tooling.preview.Preview
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.unit.DpSize
+import androidx.compose.ui.unit.dp
+import androidx.compose.ui.window.WindowState
+import androidx.compose.ui.window.singleWindowApplication
+
+fun main() =
+    singleWindowApplication(
+        title = "Chat",
+        state = WindowState(size = DpSize(500.dp, 800.dp))
+    ) {
+        ChatApp()
+    }
+
+@Preview
+@Composable
+fun ChatPreview() {
+    ChatApp()
+}

experimental/examples/chat-mpp/src/jsMain/kotlin/currentTime.js.kt

@@ -0,0 +1,5 @@
+import kotlin.js.Date
+
+actual fun timestampMs(): Long {
+    return Date.now().toLong()
+}

experimental/examples/chat-mpp/src/jsMain/kotlin/main.js.kt

@@ -0,0 +1,16 @@
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.window.Window
+import org.jetbrains.skiko.wasm.onWasmReady
+
+fun main() {
+    onWasmReady {
+        Window("Chat") {
+            Column(modifier = Modifier.fillMaxSize()) {
+                ChatApp()
+            }
+        }
+    }
+}
+

experimental/examples/chat-mpp/src/jsMain/resources/index.html

@@ -0,0 +1,15 @@
+<!DOCTYPE html>
+<html lang="en">
+<head>
+    <meta charset="UTF-8">
+    <title>compose multiplatform web demo</title>
+    <script src="skiko.js"> </script>
+    <link type="text/css" rel="stylesheet" href="styles.css" />
+</head>
+<body>
+    <div>
+        <canvas id="ComposeTarget" width="600" height="600"></canvas>
+    </div>
+    <script src="chat-mpp.js"> </script>
+</body>
+</html>

experimental/examples/chat-mpp/src/jsMain/resources/styles.css

@@ -0,0 +1,8 @@
+#root {
+    width: 100%;
+    height: 100vh;
+}
+
+#root > .compose-web-column > div {
+    position: relative;
+}

experimental/examples/chat-mpp/src/macosMain/kotlin/currentTime.macos.kt

@@ -0,0 +1,6 @@
+import platform.Foundation.NSDate
+import platform.Foundation.timeIntervalSince1970
+
+actual fun timestampMs(): Long {
+    return NSDate().timeIntervalSince1970().toLong()
+}

experimental/examples/chat-mpp/src/macosMain/kotlin/main.macos.kt

@@ -0,0 +1,11 @@
+import androidx.compose.ui.window.Window
+import platform.AppKit.NSApp
+import platform.AppKit.NSApplication
+
+fun main() {
+    NSApplication.sharedApplication()
+    Window("Chat App") {
+        ChatApp()
+    }
+    NSApp?.run()
+}

experimental/examples/chat-mpp/src/uikitMain/kotlin/currentTime.uikit.kt

@@ -0,0 +1,6 @@
+import platform.Foundation.NSDate
+import platform.Foundation.timeIntervalSince1970
+
+actual fun timestampMs(): Long {
+    return (NSDate().timeIntervalSince1970() * 1000).toLong()
+}

experimental/examples/chat-mpp/src/uikitMain/kotlin/main.uikit.kt

@@ -0,0 +1,37 @@
+import androidx.compose.ui.window.Application
+import kotlinx.cinterop.*
+import platform.UIKit.*
+import platform.Foundation.*
+
+fun main() {
+    val args = emptyArray<String>()
+    memScoped {
+        val argc = args.size + 1
+        val argv = (arrayOf("skikoApp") + args).map { it.cstr.ptr }.toCValues()
+        autoreleasepool {
+            UIApplicationMain(argc, argv, null, NSStringFromClass(SkikoAppDelegate))
+        }
+    }
+}
+
+class SkikoAppDelegate : UIResponder, UIApplicationDelegateProtocol {
+    companion object : UIResponderMeta(), UIApplicationDelegateProtocolMeta
+
+    @ObjCObjectBase.OverrideInit
+    constructor() : super()
+
+    private var _window: UIWindow? = null
+    override fun window() = _window
+    override fun setWindow(window: UIWindow?) {
+        _window = window
+    }
+
+    override fun application(application: UIApplication, didFinishLaunchingWithOptions: Map<Any?, *>?): Boolean {
+        window = UIWindow(frame = UIScreen.mainScreen.bounds)
+        window!!.rootViewController = Application("Chat") {
+            ChatApp()
+        }
+        window!!.makeKeyAndVisible()
+        return true
+    }
+}

experimental/examples/falling-balls-mpp/src/uikitMain/kotlin/main.uikit.kt

@@ -3,7 +3,6 @@
  * Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE.txt file.
  */
 
-// Use `xcodegen` first, then `open ./ComposeFallingBalls.xcodeproj` and then Run button in XCode.
 import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.height

experimental/examples/minesweeper/src/uikitMain/kotlin/main.uikit.kt

@@ -3,7 +3,6 @@
  * Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE.txt file.
  */
 
-// Use `xcodegen` first, then `open ./ComposeMinesweeper.xcodeproj` and then Run button in XCode.
 import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.height