Show download exceptions properly in CLI

.gitignore

@@ -1,9 +1,9 @@
 
-# Created by https://www.gitignore.io/api/java,gradle,intellij
+# Created by https://www.toptal.com/developers/gitignore/api/java,gradle,intellij+all
-# Edit at https://www.gitignore.io/?templates=java,gradle,intellij
+# Edit at https://www.toptal.com/developers/gitignore?templates=java,gradle,intellij+all
 
-### Intellij ###
+### Intellij+all ###
-# Covers JetBrains IDEs: IntelliJ, RubyMine, PhpStorm, AppCode, PyCharm, CLion, Android Studio and WebStorm
+# Covers JetBrains IDEs: IntelliJ, RubyMine, PhpStorm, AppCode, PyCharm, CLion, Android Studio, WebStorm and Rider
 # Reference: https://intellij-support.jetbrains.com/hc/en-us/articles/206544839
 
 # User-specific stuff
@@ -33,6 +33,9 @@
 # When using Gradle or Maven with auto-import, you should exclude module files,
 # since they will be recreated, and may cause churn.  Uncomment if using
 # auto-import.
+# .idea/artifacts
+# .idea/compiler.xml
+# .idea/jarRepositories.xml
 # .idea/modules.xml
 # .idea/*.iml
 # .idea/modules
@@ -72,13 +75,18 @@ fabric.properties
 # Android studio 3.1+ serialized cache file
 .idea/caches/build_file_checksums.ser
 
-### Intellij Patch ###
+### Intellij+all Patch ###
-# Comment Reason: https://github.com/joeblau/gitignore.io/issues/186#issuecomment-215987721
+# Ignores the whole .idea folder and all .iml files
+# See https://github.com/joeblau/gitignore.io/issues/186 and https://github.com/joeblau/gitignore.io/issues/360
 
-# *.iml
+.idea/
-# modules.xml
+
-# .idea/misc.xml
+# Reason: https://github.com/joeblau/gitignore.io/issues/186#issuecomment-249601023
-# *.ipr
+
+*.iml
+modules.xml
+.idea/misc.xml
+*.ipr
 
 # Sonarlint plugin
 .idea/sonarlint
@@ -127,4 +135,4 @@ gradle-app.setting
 ### Gradle Patch ###
 **/build/
 
-# End of https://www.gitignore.io/api/java,gradle,intellij
+# End of https://www.toptal.com/developers/gitignore/api/java,gradle,intellij+all

.idea/codeStyles/codeStyleConfig.xml

@@ -1,5 +0,0 @@
-<component name="ProjectCodeStyleConfiguration">
-  <state>
-    <option name="PREFERRED_PROJECT_CODE_STYLE" value="Default" />
-  </state>
-</component>

.idea/inspectionProfiles/Project_Default.xml

@@ -1,36 +0,0 @@
-<component name="InspectionProjectProfileManager">
-  <profile version="1.0">
-    <option name="myName" value="Project Default" />
-    <inspection_tool class="JavaDoc" enabled="true" level="WARNING" enabled_by_default="true">
-      <option name="TOP_LEVEL_CLASS_OPTIONS">
-        <value>
-          <option name="ACCESS_JAVADOC_REQUIRED_FOR" value="none" />
-          <option name="REQUIRED_TAGS" value="" />
-        </value>
-      </option>
-      <option name="INNER_CLASS_OPTIONS">
-        <value>
-          <option name="ACCESS_JAVADOC_REQUIRED_FOR" value="none" />
-          <option name="REQUIRED_TAGS" value="" />
-        </value>
-      </option>
-      <option name="METHOD_OPTIONS">
-        <value>
-          <option name="ACCESS_JAVADOC_REQUIRED_FOR" value="none" />
-          <option name="REQUIRED_TAGS" value="@return@param@throws or @exception" />
-        </value>
-      </option>
-      <option name="FIELD_OPTIONS">
-        <value>
-          <option name="ACCESS_JAVADOC_REQUIRED_FOR" value="none" />
-          <option name="REQUIRED_TAGS" value="" />
-        </value>
-      </option>
-      <option name="IGNORE_DEPRECATED" value="false" />
-      <option name="IGNORE_JAVADOC_PERIOD" value="true" />
-      <option name="IGNORE_DUPLICATED_THROWS" value="false" />
-      <option name="IGNORE_POINT_TO_ITSELF" value="false" />
-      <option name="myAdditionalJavadocTags" value="wbp.parser.entryPoint" />
-    </inspection_tool>
-  </profile>
-</component>

.idea/jarRepositories.xml

@@ -1,20 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<project version="4">
-  <component name="RemoteRepositoriesConfiguration">
-    <remote-repository>
-      <option name="id" value="central" />
-      <option name="name" value="Maven Central repository" />
-      <option name="url" value="https://repo1.maven.org/maven2" />
-    </remote-repository>
-    <remote-repository>
-      <option name="id" value="jboss.community" />
-      <option name="name" value="JBoss Community repository" />
-      <option name="url" value="https://repository.jboss.org/nexus/content/repositories/public/" />
-    </remote-repository>
-    <remote-repository>
-      <option name="id" value="BintrayJCenter" />
-      <option name="name" value="BintrayJCenter" />
-      <option name="url" value="https://jcenter.bintray.com/" />
-    </remote-repository>
-  </component>
-</project>

.idea/misc.xml

@@ -1,10 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<project version="4">
-  <component name="EntryPointsManager">
-    <list size="1">
-      <item index="0" class="java.lang.String" itemvalue="com.google.gson.annotations.SerializedName" />
-    </list>
-  </component>
-  <component name="ExternalStorageConfigurationManager" enabled="true" />
-  <component name="ProjectRootManager" version="2" languageLevel="JDK_1_8" default="false" project-jdk-name="11" project-jdk-type="JavaSDK" />
-</project>

.idea/vcs.xml

@@ -1,6 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<project version="4">
-  <component name="VcsDirectoryMappings">
-    <mapping directory="" vcs="Git" />
-  </component>
-</project>

README.md

@@ -1,2 +1,2 @@
 # packwiz-installer
-An installer for launching packwiz modpacks with MultiMC.
+An installer for launching packwiz modpacks with MultiMC. You'll need [the bootstrapper](https://github.com/comp500/packwiz-installer-bootstrap/releases) to actually use this.

src/main/java/link/infra/packwiz/installer/metadata/hash/Murmur2Lib.java

@@ -74,13 +74,13 @@ public class Murmur2Lib {
     int left = length - len_m;
     if (left != 0) {
       if (left >= 3) {
-        h ^= (int) data[length - 3] << 16;
+        h ^= (int) data[length - (left - 2)] << 16;
       }
       if (left >= 2) {
-        h ^= (int) data[length - 2] << 8;
+        h ^= (int) data[length - (left - 1)] << 8;
       }
       if (left >= 1) {
-        h ^= (int) data[length - 1];
+        h ^= data[length - left];
       }
 
       h *= M_32;
@@ -152,7 +152,7 @@ public class Murmur2Lib {
       case 2:
         h ^= (long) (data[tailStart + 1] & 0xff) << 8;
       case 1:
-        h ^= (long) (data[tailStart] & 0xff);
+        h ^= data[tailStart] & 0xff;
         h *= M_64;
     }
 

src/main/kotlin/link/infra/packwiz/installer/DownloadTask.kt

@@ -152,6 +152,9 @@ internal class DownloadTask private constructor(val metadata: IndexFile.File, de
 			}
 		}
 
+		// TODO: if already exists and has correct hash, ignore?
+		// TODO: add .disabled support?
+
 		try {
 			val hash: Hash
 			val fileHashFormat: String
@@ -176,7 +179,14 @@ internal class DownloadTask private constructor(val metadata: IndexFile.File, de
 			}
 
 			if (fileSource.hashIsEqual(hash)) {
-				Files.createDirectories(destPath.parent)
+				// isDirectory follows symlinks, but createDirectories doesn't
+				try {
+					Files.createDirectories(destPath.parent)
+				} catch (e: FileAlreadyExistsException) {
+					if (!Files.isDirectory(destPath.parent)) {
+						throw e
+					}
+				}
 				Files.copy(data.inputStream(), destPath, StandardCopyOption.REPLACE_EXISTING)
 				data.clear()
 			} else {

src/main/kotlin/link/infra/packwiz/installer/Main.kt

@@ -1,3 +1,5 @@
+@file:JvmName("Main")
+
 package link.infra.packwiz.installer
 
 import link.infra.packwiz.installer.metadata.SpaceSafeURI
@@ -16,6 +18,9 @@ import kotlin.system.exitProcess
 
 @Suppress("unused")
 class Main(args: Array<String>) {
+	// Don't attempt to start a GUI if we are headless
+	var guiEnabled = !GraphicsEnvironment.isHeadless()
+
 	private fun startup(args: Array<String>) {
 		val options = Options()
 		addNonBootstrapOptions(options)
@@ -26,19 +31,24 @@ class Main(args: Array<String>) {
 			parser.parse(options, args)
 		} catch (e: ParseException) {
 			e.printStackTrace()
-			try {
+			if (guiEnabled) {
-				UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName())
+				EventQueue.invokeAndWait {
-			} catch (e1: Exception) {
+					try {
-				// Ignore the exceptions, just continue using the ugly L&F
+						UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName())
+					} catch (ignored: Exception) {
+						// Ignore the exceptions, just continue using the ugly L&F
+					}
+					JOptionPane.showMessageDialog(null, e.message, "packwiz-installer", JOptionPane.ERROR_MESSAGE)
+				}
 			}
-			JOptionPane.showMessageDialog(null, e.message, "packwiz-installer", JOptionPane.ERROR_MESSAGE)
 			exitProcess(1)
 		}
 
-		// if "headless", GUI creation will fail anyway!
+		if (guiEnabled && cmd.hasOption("no-gui")) {
-		val ui = if (cmd.hasOption("no-gui") || GraphicsEnvironment.isHeadless()) {
+			guiEnabled = false
-			CLIHandler()
+		}
-		} else InstallWindow()
+
+		val ui = if (guiEnabled) InstallWindow() else CLIHandler()
 
 		val unparsedArgs = cmd.args
 		if (unparsedArgs.size > 1) {
@@ -47,15 +57,13 @@ class Main(args: Array<String>) {
 			ui.handleExceptionAndExit(RuntimeException("URI to install from must be specified!"))
 		}
 
-		cmd.getOptionValue("title")?.also {
+		cmd.getOptionValue("title")?.also(ui::setTitle)
-			ui.setTitle(it)
-		}
 
 		val inputStateHandler = InputStateHandler()
 		ui.show(inputStateHandler)
 
 		val uOptions = UpdateManager.Options().apply {
-			side = cmd.getOptionValue("side")?.let { UpdateManager.Options.Side.from(it) } ?: side
+			side = cmd.getOptionValue("side")?.let((UpdateManager.Options.Side)::from) ?: side
 			packFolder = cmd.getOptionValue("pack-folder") ?: packFolder
 			manifestFile = cmd.getOptionValue("meta-file") ?: manifestFile
 		}
@@ -84,6 +92,7 @@ class Main(args: Array<String>) {
 
 	companion object {
 		// Called by packwiz-installer-bootstrap to set up the help command
+		@JvmStatic
 		fun addNonBootstrapOptions(options: Options) {
 			options.addOption("s", "side", true, "Side to install mods from (client/server, defaults to client)")
 			options.addOption(null, "title", true, "Title of the installer window")
@@ -92,6 +101,7 @@ class Main(args: Array<String>) {
 		}
 
 		// TODO: link these somehow so they're only defined once?
+		@JvmStatic
 		private fun addBootstrapOptions(options: Options) {
 			options.addOption(null, "bootstrap-update-url", true, "Github API URL for checking for updates")
 			options.addOption(null, "bootstrap-update-token", true, "Github API Access Token, for private repositories")
@@ -109,11 +119,13 @@ class Main(args: Array<String>) {
 			startup(args)
 		} catch (e: Exception) {
 			e.printStackTrace()
-			EventQueue.invokeLater {
+			if (guiEnabled) {
-				JOptionPane.showMessageDialog(null,
+				EventQueue.invokeLater {
+					JOptionPane.showMessageDialog(null,
 						"A fatal error occurred: \n" + e.javaClass.canonicalName + ": " + e.message,
 						"packwiz-installer", JOptionPane.ERROR_MESSAGE)
-				exitProcess(1)
+					exitProcess(1)
+				}
 			}
 			// In case the EventQueue is broken, exit after 1 minute
 			Thread.sleep(60 * 1000.toLong())

src/main/kotlin/link/infra/packwiz/installer/UpdateManager.kt

@@ -126,7 +126,6 @@ class UpdateManager internal constructor(private val opts: Options, val ui: IUse
 
 		ui.submitProgress(InstallProgress("Loading pack file..."))
 		val packFileSource = try {
-			Objects.requireNonNull(opts.downloadURI)
 			val src = getFileSource(opts.downloadURI!!)
 			getHasher("sha256").getHashingSource(src)
 		} catch (e: Exception) {
@@ -191,12 +190,16 @@ class UpdateManager internal constructor(private val opts: Options, val ui: IUse
 			handleCancellation()
 		}
 		try {
-			// This is badly written, I'll probably heavily refactor it at some point
+			val index = pf.index!!
-			// The port to Kotlin made this REALLY messy!!!!
+			getNewLoc(opts.downloadURI, index.file)?.let { newLoc ->
-			getNewLoc(opts.downloadURI, Objects.requireNonNull(pf.index)!!.file)?.let {
+				index.hashFormat?.let { hashFormat ->
-				pf.index!!.hashFormat?.let { it1 ->
+					processIndex(
-					processIndex(it,
+						newLoc,
-							getHash(Objects.requireNonNull(pf.index!!.hashFormat)!!, Objects.requireNonNull(pf.index!!.hash)!!), it1, manifest, invalidatedUris)
+						getHash(index.hashFormat!!, index.hash!!),
+						hashFormat,
+						manifest,
+						invalidatedUris
+					)
 				}
 			}
 		} catch (e1: Exception) {
@@ -252,8 +255,7 @@ class UpdateManager internal constructor(private val opts: Options, val ui: IUse
 			return
 		}
 		if (!indexFileSource.hashIsEqual(indexHash)) {
-			// TODO: throw exception
+			ui.handleExceptionAndExit(RuntimeException("Your index hash is invalid! Please run packwiz refresh on the pack again"))
-			println("I was meant to put an error message here but I'll do that later")
 			return
 		}
 		if (stateHandler.cancelButton) {

src/main/kotlin/link/infra/packwiz/installer/metadata/hash/Murmur2Hasher.kt

@@ -10,7 +10,7 @@ class Murmur2Hasher : IHasher {
 		val tempBuffer = Buffer()
 
 		override val hash: Hash by lazy(LazyThreadSafetyMode.NONE) {
-			val data = computeNormalizedArray(internalBuffer.readByteArray())
+			val data = internalBuffer.readByteArray()
 			Murmur2Hash(Murmur2Lib.hash32(data, data.size, 1))
 		}
 
@@ -19,27 +19,42 @@ class Murmur2Hasher : IHasher {
 			val out = delegate.read(tempBuffer, byteCount)
 			if (out > -1) {
 				sink.write(tempBuffer.clone(), out)
-				internalBuffer.write(tempBuffer, out)
+				computeNormalizedBufferFaster(tempBuffer, internalBuffer)
 			}
 			return out
 		}
 
 		// Credit to https://github.com/modmuss50/CAV2/blob/master/murmur.go
-		private fun computeNormalizedArray(input: ByteArray): ByteArray {
+//		private fun computeNormalizedArray(input: ByteArray): ByteArray {
-			val output = ByteArray(input.size)
+//			val output = ByteArray(input.size)
+//			var index = 0
+//			for (b in input) {
+//				when (b) {
+//					9.toByte(), 10.toByte(), 13.toByte(), 32.toByte() -> {}
+//					else -> {
+//						output[index] = b
+//						index++
+//					}
+//				}
+//			}
+//			val outputTrimmed = ByteArray(index)
+//			System.arraycopy(output, 0, outputTrimmed, 0, index)
+//			return outputTrimmed
+//		}
+
+		private fun computeNormalizedBufferFaster(input: Buffer, output: Buffer) {
 			var index = 0
-			for (b in input) {
+			val arr = input.readByteArray()
-				when (b.toInt()) {
+			for (b in arr) {
-					9, 10, 13, 32 -> {}
+				when (b) {
+					9.toByte(), 10.toByte(), 13.toByte(), 32.toByte() -> {}
 					else -> {
-						output[index] = b
+						arr[index] = b
 						index++
 					}
 				}
 			}
-			val outputTrimmed = ByteArray(index)
+			output.write(arr, 0, index)
-			System.arraycopy(output, 0, outputTrimmed, 0, index)
-			return outputTrimmed
 		}
 
 	}

src/main/kotlin/link/infra/packwiz/installer/request/HandlerManager.kt

@@ -1,6 +1,7 @@
 package link.infra.packwiz.installer.request
 
 import link.infra.packwiz.installer.metadata.SpaceSafeURI
+import link.infra.packwiz.installer.request.handlers.RequestHandlerFile
 import link.infra.packwiz.installer.request.handlers.RequestHandlerGithub
 import link.infra.packwiz.installer.request.handlers.RequestHandlerHTTP
 import okio.Source
@@ -9,7 +10,8 @@ object HandlerManager {
 
 	private val handlers: List<IRequestHandler> = listOf(
 			RequestHandlerGithub(),
-			RequestHandlerHTTP()
+			RequestHandlerHTTP(),
+			RequestHandlerFile()
 	)
 
 	@JvmStatic

src/main/kotlin/link/infra/packwiz/installer/request/handlers/RequestHandlerFile.kt

@@ -0,0 +1,18 @@
+package link.infra.packwiz.installer.request.handlers
+
+import link.infra.packwiz.installer.metadata.SpaceSafeURI
+import link.infra.packwiz.installer.request.IRequestHandler
+import okio.Source
+import okio.source
+import java.nio.file.Paths
+
+open class RequestHandlerFile : IRequestHandler {
+	override fun matchesHandler(loc: SpaceSafeURI): Boolean {
+		return "file" == loc.scheme
+	}
+
+	override fun getFileSource(loc: SpaceSafeURI): Source? {
+		val path = Paths.get(loc.toURL().toURI())
+		return path.source()
+	}
+}

src/main/kotlin/link/infra/packwiz/installer/request/handlers/RequestHandlerGithub.kt

@@ -65,7 +65,7 @@ class RequestHandlerGithub : RequestHandlerZip(true) {
 		if (!("http" == scheme || "https" == scheme)) {
 			return false
 		}
-		return "github.com" == loc.host
+		// TODO: more match testing?
-		// TODO: sanity checks, support for more github urls
+		return "github.com" == loc.host && branchMatcherPattern.matcher(loc.path).matches()
 	}
 }

src/main/kotlin/link/infra/packwiz/installer/request/handlers/RequestHandlerHTTP.kt

@@ -4,6 +4,7 @@ import link.infra.packwiz.installer.metadata.SpaceSafeURI
 import link.infra.packwiz.installer.request.IRequestHandler
 import okio.Source
 import okio.source
+import java.net.HttpURLConnection
 
 open class RequestHandlerHTTP : IRequestHandler {
 	override fun matchesHandler(loc: SpaceSafeURI): Boolean {
@@ -12,14 +13,17 @@ open class RequestHandlerHTTP : IRequestHandler {
 	}
 
 	override fun getFileSource(loc: SpaceSafeURI): Source? {
-		val conn = loc.toURL().openConnection()
+		val conn = loc.toURL().openConnection() as HttpURLConnection
 		// TODO: when do we send specific headers??? should there be a way to signal this?
-		// github *sometimes* requires it, sometimes not!
+		conn.addRequestProperty("Accept", "application/octet-stream")
-		//conn.addRequestProperty("Accept", "application/octet-stream");
+		// TODO: include version?
+		conn.addRequestProperty("User-Agent", "packwiz-installer")
+
 		conn.apply {
 			// 30 second read timeout
 			readTimeout = 30 * 1000
+			requestMethod = "GET"
 		}
-		return conn.getInputStream().source()
+		return conn.inputStream.source()
 	}
 }

src/main/kotlin/link/infra/packwiz/installer/ui/CLIHandler.kt

@@ -3,6 +3,7 @@ package link.infra.packwiz.installer.ui
 import link.infra.packwiz.installer.ui.IUserInterface.ExceptionListResult
 import java.util.concurrent.CompletableFuture
 import java.util.concurrent.Future
+import kotlin.system.exitProcess
 
 class CLIHandler : IUserInterface {
 	override fun handleException(e: Exception) {
@@ -40,8 +41,11 @@ class CLIHandler : IUserInterface {
 	}
 
 	override fun showExceptions(exceptions: List<ExceptionDetails>, numTotal: Int, allowsIgnore: Boolean): Future<ExceptionListResult> {
-		val future = CompletableFuture<ExceptionListResult>()
+		println("Failed to download modpack, the following errors were encountered:")
-		future.complete(ExceptionListResult.CANCEL)
+		for (ex in exceptions) {
-		return future
+			println(ex.name + ": ")
+			ex.exception.printStackTrace()
+		}
+		exitProcess(1)
 	}
 }

src/main/kotlin/link/infra/packwiz/installer/ui/InstallWindow.kt

@@ -10,10 +10,10 @@ import javax.swing.border.EmptyBorder
 import kotlin.system.exitProcess
 
 class InstallWindow : IUserInterface {
-	private val frmPackwizlauncher: JFrame
+	private lateinit var frmPackwizlauncher: JFrame
-	private val lblProgresslabel: JLabel
+	private lateinit var lblProgresslabel: JLabel
-	private val progressBar: JProgressBar
+	private lateinit var progressBar: JProgressBar
-	private val btnOptions: JButton
+	private lateinit var btnOptions: JButton
 
 	private var inputStateHandler: InputStateHandler? = null
 	private var title = "Updating modpack..."
@@ -23,55 +23,57 @@ class InstallWindow : IUserInterface {
 	// TODO: separate JFrame junk from IUserInterface junk?
 
 	init {
-		frmPackwizlauncher = JFrame().apply {
+		EventQueue.invokeAndWait {
-			title = this@InstallWindow.title
+			frmPackwizlauncher = JFrame().apply {
-			setBounds(100, 100, 493, 95)
+				title = this@InstallWindow.title
-			defaultCloseOperation = JFrame.EXIT_ON_CLOSE
+				setBounds(100, 100, 493, 95)
-			setLocationRelativeTo(null)
+				defaultCloseOperation = JFrame.EXIT_ON_CLOSE
+				setLocationRelativeTo(null)
 
-			// Progress bar and loading text
+				// Progress bar and loading text
-			add(JPanel().apply {
+				add(JPanel().apply {
-				border = EmptyBorder(10, 10, 10, 10)
+					border = EmptyBorder(10, 10, 10, 10)
-				layout = BorderLayout(0, 0)
+					layout = BorderLayout(0, 0)
 
-				progressBar = JProgressBar().apply {
+					progressBar = JProgressBar().apply {
-					isIndeterminate = true
+						isIndeterminate = true
-				}
-				add(progressBar, BorderLayout.CENTER)
-
-				lblProgresslabel = JLabel("Loading...")
-				add(lblProgresslabel, BorderLayout.SOUTH)
-			}, BorderLayout.CENTER)
-
-			// Buttons
-			add(JPanel().apply {
-				border = EmptyBorder(0, 5, 0, 5)
-				layout = GridBagLayout()
-
-				btnOptions = JButton("Optional mods...").apply {
-					alignmentX = Component.CENTER_ALIGNMENT
-
-					addActionListener {
-						text = "Loading..."
-						isEnabled = false
-						inputStateHandler?.pressOptionsButton()
 					}
-				}
+					add(progressBar, BorderLayout.CENTER)
-				add(btnOptions, GridBagConstraints().apply {
-					gridx = 0
-					gridy = 0
-				})
 
-				add(JButton("Cancel").apply {
+					lblProgresslabel = JLabel("Loading...")
-					addActionListener {
+					add(lblProgresslabel, BorderLayout.SOUTH)
-						isEnabled = false
+				}, BorderLayout.CENTER)
-						inputStateHandler?.pressCancelButton()
+
+				// Buttons
+				add(JPanel().apply {
+					border = EmptyBorder(0, 5, 0, 5)
+					layout = GridBagLayout()
+
+					btnOptions = JButton("Optional mods...").apply {
+						alignmentX = Component.CENTER_ALIGNMENT
+
+						addActionListener {
+							text = "Loading..."
+							isEnabled = false
+							inputStateHandler?.pressOptionsButton()
+						}
 					}
-				}, GridBagConstraints().apply {
+					add(btnOptions, GridBagConstraints().apply {
-					gridx = 0
+						gridx = 0
-					gridy = 1
+						gridy = 0
-				})
+					})
-			}, BorderLayout.EAST)
+
+					add(JButton("Cancel").apply {
+						addActionListener {
+							isEnabled = false
+							inputStateHandler?.pressCancelButton()
+						}
+					}, GridBagConstraints().apply {
+						gridx = 0
+						gridy = 1
+					})
+				}, BorderLayout.EAST)
+			}
 		}
 	}
 
@@ -178,9 +180,16 @@ class InstallWindow : IUserInterface {
 	override fun showOptions(options: List<IOptionDetails>): Future<Boolean> {
 		val future = CompletableFuture<Boolean>()
 		EventQueue.invokeLater {
-			OptionsSelectWindow(options, future, frmPackwizlauncher).apply {
+			if (options.isEmpty()) {
-				defaultCloseOperation = JDialog.DISPOSE_ON_CLOSE
+				JOptionPane.showMessageDialog(null,
-				isVisible = true
+					"This modpack has no optional mods!",
+					"Optional mods", JOptionPane.INFORMATION_MESSAGE)
+				future.complete(false)
+			} else {
+				OptionsSelectWindow(options, future, frmPackwizlauncher).apply {
+					defaultCloseOperation = JDialog.DISPOSE_ON_CLOSE
+					isVisible = true
+				}
 			}
 		}
 		return future
@@ -199,7 +208,7 @@ class InstallWindow : IUserInterface {
 
 	override fun disableOptionsButton() {
 		btnOptions.apply {
-			text = "Optional mods..."
+			text = "No optional mods"
 			isEnabled = false
 		}
 	}