buildtools.gradle

import groovy.json.JsonSlurper

def buildToolsFolder = new File(project.buildDir, "buildtools")
def downloadFolder = new File(buildToolsFolder, "download")
def mcversion = '1.18.2'

private static def getVersions() {
    List<String> versionList = new ArrayList<>()
    Map versions = new JsonSlurper().parse(new URL('https://launchermeta.mojang.com/mc/game/version_manifest.json'))
    for(def versionObj : versions.versions) {
        if(versionObj.type == 'release') {
            versionList.add(versionObj.id)
        }
    }
    return versionList
}

task setMCVersion() {

}

task checkVersion() {
    def versionList = getVersions()
    if(!versionList.contains(mcversion)) {
        mcversion = 'latest'
        println "Version ${mcversion} is not available. Using latest version latest instead."
    }
}

task downloadBuildTools(type: Download) {
    dependsOn(checkVersion)
    downloadFolder.mkdirs()
    src 'https://hub.spigotmc.org/jenkins/job/BuildTools/lastSuccessfulBuild/artifact/target/BuildTools.jar'
    dest file(downloadFolder.absolutePath + '/BuildTools.jar')
    onlyIfModified true
}

task cleanBuildTools(type: Delete) {
    file(downloadFolder).delete()
}

task runBuildTools(type: Exec) {
    dependsOn(downloadBuildTools)
    finalizedBy(cleanBuildTools)
    def workingDirectory = new File(buildToolsFolder, mcversion)
    workingDirectory.mkdirs()
    setWorkingDir(workingDirectory.absolutePath)
    commandLine "java", '-jar', "${downloadFolder.absolutePath}/BuildTools.jar", '--remapped', '--compile-if-changed', "--rev", mcversion
}