testplugin.gradle

import java.nio.file.Files
import java.nio.file.StandardCopyOption


abstract class TestPluginTask extends DefaultTask {
    @Input
    String serverVersion = '1.19.2'
    @Input
    String pluginJar = "${project.name}-${project.version}-${System.getenv('BUILD_NUMBER') ?: 'DEV'}.jar"

    @TaskAction
    void run() {
        def serverFolder = new File(project.buildDir, 'server')
        def serverFile = new File(serverFolder, 'server.jar')
        def eulaFile = new File(serverFolder, 'eula.txt')

        if (!serverFolder.exists()) {
            System.out.println("Downloading Paper ${serverVersion}...")
            serverFolder.mkdir()

            def url = "";
            switch (serverVersion) {
                case "1.19.2":
                    url = "https://api.papermc.io/v2/projects/paper/versions/1.19.2/builds/282/downloads/paper-1.19.2-282.jar"
                    break;
                case "1.12.2":
                    url = "https://api.papermc.io/v2/projects/paper/versions/1.12.2/builds/1620/downloads/paper-1.12.2-1620.jar"
                    break;
                case "1.8.8":
                    url = "https://api.papermc.io/v2/projects/paper/versions/1.8.8/builds/445/downloads/paper-1.8.8-445.jar"
                    break;
                default:
                    throw new IllegalArgumentException("Unsupported server version: ${serverVersion}")
            }

            serverFile.withOutputStream { os ->
                new URL(url).openStream().withStream { is ->
                    os << is
                }
            }
        }

        if (!eulaFile.exists()) {
            System.out.println("Applying EULA...")
            eulaFile.createNewFile()
            eulaFile << 'eula=true'
            System.out.println("EULA applied!")
        }

        def pluginsFolder = new File(serverFolder, 'plugins')
        if(!pluginsFolder.exists()) {
            System.out.println("Creating plugins folder...")
            pluginsFolder.mkdir()
            System.out.println("Plugins folder created!")
        }

        System.out.println("Copying plugin jar...")
        def pluginBuild = new File(project.buildDir, 'libs/'+ pluginJar)
        def finalPlugin = new File(pluginsFolder, pluginJar)
        Files.copy(pluginBuild.toPath(), finalPlugin.toPath(), StandardCopyOption.REPLACE_EXISTING)
        System.out.println("Plugin jar copied!")

        System.out.println("Starting server...")
        project.javaexec {
            args = ['-jar', serverFile.name, '--nogui']
            workingDir = serverFolder
            standardInput = System.in
            mainClass.set("-Dfile.encoding=UTF-8")
        }

        System.out.println("Server stopped!")
    }
}

tasks.register('testPlugin', TestPluginTask) {
    dependsOn 'shadowJar'
}