@file:Suppress("DEPRECATION")

import org.gradle.api.Plugin
import org.gradle.api.Project
import org.gradle.api.Task
import org.gradle.api.artifacts.Dependency
import javax.xml.parsers.DocumentBuilderFactory

class CheckLibVersionsPlugin : Plugin<Project> {
    override fun apply(project: Project) {
        project.task("checkLibVersions") {
            description =
                "Find any 3rd party libraries which have released new versions to the central Maven repo since we last upgraded."
            doLast {
                project.configurations.flatMap { it.allDependencies }
                    .toSet()
                    .forEach { checkDependency(it) }
            }
        }
    }

    private fun Task.checkDependency(dependency: Dependency) {
        val version = dependency.version
        val group = dependency.group
        val path = group?.replace(".", "/") ?: ""
        val name = dependency.name
        val metaDataUrl = "https://repo1.maven.org/maven2/$path/$name/maven-metadata.xml"
        try {
            val dbf = DocumentBuilderFactory.newInstance()
            val db = dbf.newDocumentBuilder()
            val doc = db.parse(metaDataUrl);
            val newest = doc.getElementsByTagName("latest").item(0).textContent
            if (version != newest.toString()) {
                println("UPGRADE {\"group\": \"$group\", \"name\": \"$name\", \"current\": \"$version\", \"latest\": \"$newest\"}")
            }
        } catch (e: Throwable) {
            logger.debug("Unable to download or parse {}: {}", metaDataUrl, e.message)
        }
    }
}