Download WiX toolset on Windows

It is a non-optional dependency for jpackage
(see "Dependencies" section of https://openjdk.java.net/jeps/343).

gradle-plugins/compose-desktop-application/build.gradle.kts

@@ -1,8 +1,11 @@
+import com.github.jengelman.gradle.plugins.shadow.tasks.ShadowJar
+
 plugins {
     kotlin("jvm")
     id("com.gradle.plugin-publish")
     id("java-gradle-plugin")
     id("maven-publish")
+    id("com.github.johnrengelman.shadow") version "6.1.0"
 }
 
 gradlePluginConfig {
@@ -13,8 +16,32 @@ gradlePluginConfig {
     implementationClass = "org.jetbrains.compose.desktop.application.ApplicationPlugin"
 }
 
+val embedded by configurations.creating
+
 dependencies {
+    fun embeddedCompileOnly(dep: String) {
+        compileOnly(dep)
+        embedded(dep)
+    }
+
     compileOnly(gradleApi())
     compileOnly(kotlin("gradle-plugin-api"))
     compileOnly(kotlin("gradle-plugin"))
+    // include relocated download task to avoid potential runtime conflicts
+    embeddedCompileOnly("de.undercouch:gradle-download-task:4.1.1")
 }
+
+val shadow = tasks.named<ShadowJar>("shadowJar") {
+    val fromPackage = "de.undercouch"
+    val toPackage = "org.jetbrains.compose.$fromPackage"
+    relocate(fromPackage, toPackage)
+    archiveClassifier.set("shadow")
+    configurations = listOf(embedded)
+    exclude("META-INF/gradle-plugins/de.undercouch.download.properties")
+}
+
+val jar = tasks.named<Jar>("jar") {
+    dependsOn(shadow)
+    from(zipTree(shadow.get().archiveFile))
+    this.duplicatesStrategy = DuplicatesStrategy.INCLUDE
+}

gradle-plugins/compose-desktop-application/src/main/kotlin/org/jetbrains/compose/desktop/application/ApplicationPlugin.kt

@@ -12,6 +12,7 @@ import org.jetbrains.compose.desktop.DesktopExtension
 import org.jetbrains.compose.desktop.application.dsl.Application
 import org.jetbrains.compose.desktop.application.dsl.ConfigurationSource
 import org.jetbrains.compose.desktop.application.internal.OS
+import org.jetbrains.compose.desktop.application.internal.configureWix
 import org.jetbrains.compose.desktop.application.internal.currentOS
 import org.jetbrains.compose.desktop.application.internal.provider
 import org.jetbrains.compose.desktop.application.tasks.AbstractJPackageTask
@@ -22,7 +23,6 @@ import java.util.*
 
 private const val PLUGIN_ID = "org.jetbrains.compose.desktop.application"
 
-// todo: fix windows
 // todo: multiple launchers
 // todo: file associations
 // todo: use workers
@@ -43,6 +43,7 @@ open class ApplicationPlugin : Plugin<Project> {
         }
         project.afterEvaluate {
             project.configurePackagingTasks(listOf(mainApplication))
+            project.configureWix()
         }
     }
 }

gradle-plugins/compose-desktop-application/src/main/kotlin/org/jetbrains/compose/desktop/application/internal/wixToolset.kt

@@ -0,0 +1,55 @@
+package org.jetbrains.compose.desktop.application.internal
+
+import de.undercouch.gradle.tasks.download.Download
+import org.gradle.api.Project
+import org.gradle.api.tasks.Copy
+import org.jetbrains.compose.desktop.application.tasks.AbstractJPackageTask
+import java.io.File
+
+internal const val DOWNLOAD_WIX_TOOLSET_TASK_NAME = "downloadWix"
+internal const val UNZIP_WIX_TOOLSET_TASK_NAME = "unzipWix"
+internal const val WIX_PATH_ENV_VAR = "WIX_PATH"
+internal const val DOWNLOAD_WIX_PROPERTY = "compose.desktop.application.downloadWix"
+
+internal fun Project.configureWix() {
+    if (currentOS != OS.Windows) return
+
+    val wixPath = System.getenv()[WIX_PATH_ENV_VAR]
+    if (wixPath != null) {
+        val wixDir = File(wixPath)
+        check(wixDir.isDirectory) { "$WIX_PATH_ENV_VAR value is not a valid directory: $wixDir" }
+        eachWindowsPackageTask {
+            wixToolsetDir.set(wixDir)
+        }
+        return
+    }
+
+    if (project.findProperty(DOWNLOAD_WIX_PROPERTY) == "false") return
+
+    val root = project.rootProject
+    val wixDir = root.buildDir.resolve("wixToolset")
+    val zipFile = wixDir.resolve("wix311.zip")
+    val unzipDir = wixDir.resolve("unpacked")
+    val download = root.tasks.maybeCreate(DOWNLOAD_WIX_TOOLSET_TASK_NAME, Download::class.java).apply {
+        onlyIf { !zipFile.isFile }
+        src("https://github.com/wixtoolset/wix3/releases/download/wix3112rtm/wix311-binaries.zip")
+        dest(zipFile)
+    }
+    val unzip = root.tasks.maybeCreate(UNZIP_WIX_TOOLSET_TASK_NAME, Copy::class.java).apply {
+        dependsOn(download)
+        from(zipTree(zipFile))
+        destinationDir = unzipDir
+    }
+    eachWindowsPackageTask {
+        dependsOn(unzip)
+        wixToolsetDir.set(unzipDir)
+    }
+}
+
+private fun Project.eachWindowsPackageTask(fn: AbstractJPackageTask.() -> Unit) {
+    tasks.withType(AbstractJPackageTask::class.java).configureEach { packageTask ->
+        if (packageTask.targetOS == OS.Windows) {
+            packageTask.fn()
+        }
+    }
+}

gradle-plugins/compose-desktop-application/src/main/kotlin/org/jetbrains/compose/desktop/application/tasks/AbstractJPackageTask.kt

@@ -12,6 +12,7 @@ import org.gradle.api.provider.ProviderFactory
 import org.gradle.api.tasks.*
 import org.gradle.api.tasks.Optional
 import org.gradle.process.ExecOperations
+import org.gradle.process.ExecSpec
 import org.jetbrains.compose.desktop.application.dsl.TargetFormat
 import org.jetbrains.compose.desktop.application.internal.OS
 import org.jetbrains.compose.desktop.application.internal.cliArg
@@ -54,6 +55,11 @@ abstract class AbstractJPackageTask @Inject constructor(
         set(providers.provider { logger.isDebugEnabled }.orElse(composeVerbose))
     }
 
+    @get:InputDirectory
+    @get:Optional
+    /** @see internal/wixToolset.kt */
+    val wixToolsetDir: DirectoryProperty = objects.directoryProperty()
+
     @get:Input
     @get:Optional
     val installationPath: Property<String?> = objects.nullableProperty()
@@ -285,12 +291,22 @@ abstract class AbstractJPackageTask @Inject constructor(
             val argsFile = composeBuildDir.resolve("${name}.args.txt")
             argsFile.writeText(args.joinToString("\n"))
 
-            execOperations.exec {
-                it.executable = jpackage.absolutePath
-                it.setArgs(listOf("@${argsFile.absolutePath}"))
+            execOperations.exec { exec ->
+                configureWixPathIfNeeded(exec)
+                exec.executable = jpackage.absolutePath
+                exec.setArgs(listOf("@${argsFile.absolutePath}"))
             }.assertNormalExitValue()
         } finally {
             tmpDir.deleteRecursively()
         }
     }
+
+    private fun configureWixPathIfNeeded(exec: ExecSpec) {
+        if (currentOS == OS.Windows) {
+            val wixDir = wixToolsetDir.asFile.orNull ?: return
+            val wixPath = wixDir.absolutePath
+            val path = System.getenv("PATH") ?: ""
+            exec.environment("PATH", "$wixPath;$path")
+        }
+    }
 }