Gradle: Add decompile task to projects (#1273)

* Gradle: Add decompile task to projects

* add ff as dependency rather than adding ti in buildsrc

* smh smh smh smh smh

* Add ff version in buildsrc build file

This doesn't work in ext as it officially isn't part of the project

* Add missing ''s

buildSrc/src/main/groovy/FernflowerPlugin.groovy

@@ -0,0 +1,16 @@
+import org.gradle.api.Plugin
+import org.gradle.api.Project
+import org.gradle.api.tasks.StopExecutionException
+
+class FernflowerPlugin implements Plugin<Project> {
+    void apply(Project project) {
+        project.task('decompile', type: FernflowerTask) {
+            it.dependsOn(project.tasks.jar)
+            it.doFirst {
+                if (!project.tasks.jar.didWork) {
+                    throw new StopExecutionException()
+                }
+            }
+        }
+    }
+}

buildSrc/src/main/groovy/FernflowerTask.groovy

@@ -0,0 +1,32 @@
+import org.gradle.api.DefaultTask
+import org.gradle.api.tasks.InputFile
+import org.gradle.api.tasks.OutputDirectory
+import org.gradle.api.tasks.TaskAction
+import org.jetbrains.java.decompiler.main.decompiler.ConsoleDecompiler
+
+class FernflowerTask extends DefaultTask {
+    List<String> extraArgs
+    String inputJar
+    String outputDir
+
+    @InputFile
+    File getInputJar() {
+        project.file(inputJar ?: project.buildDir.toString() + '/libs/' + project.getName() + '-' + project.version + '.jar')
+    }
+
+    @OutputDirectory
+    File getOutputDir() {
+        project.file(outputDir ?: project.buildDir.toString() + '/decompiled-sources')
+    }
+
+    @TaskAction
+    void decompile() {
+        getOutputDir().mkdirs()
+        def args = [getInputJar().toString(), getOutputDir().toString()]
+        if (extraArgs) {
+            args.addAll(extraArgs)
+        }
+
+        ConsoleDecompiler.main(args as String[])
+    }
+}

buildSrc/src/main/resources/META-INF/gradle-plugins/fernflower.properties

@@ -0,0 +1 @@
+implementation-class=FernflowerPlugin