feat: added update checker

Author: tarna

build.gradle.kts

@@ -77,6 +77,10 @@ bukkit {
             description = "Allows the player to use the plugin"
             default = Default.TRUE
         }
+        register("attollo.update") {
+            description = "Allows the player to see update notifications"
+            default = Default.OP
+        }
     }
     commands {
         register("attollo") {

src/main/kotlin/dev/themeinerlp/attollo/Attollo.kt

@@ -1,13 +1,14 @@
 package dev.themeinerlp.attollo
 
 import dev.themeinerlp.attollo.listener.AttolloListener
+import dev.themeinerlp.attollo.listener.UpdateCheckerListener
 import org.bukkit.Material
 import org.bukkit.plugin.java.JavaPlugin
 
 open class Attollo : JavaPlugin() {
 
-
     lateinit var elevatorBlock: Material
+
     override fun onLoad() {
         saveDefaultConfig()
     }
@@ -23,6 +24,7 @@ open class Attollo : JavaPlugin() {
         elevatorBlock = material ?: Material.DAYLIGHT_DETECTOR
         logger.info("Using elevatorBlock: $elevatorBlock")
         server.pluginManager.registerEvents(AttolloListener(this), this)
+        server.pluginManager.registerEvents(UpdateCheckerListener(this), this)
     }
 
-}
+}

src/main/kotlin/dev/themeinerlp/attollo/listener/UpdateCheckerListener.kt

@@ -0,0 +1,33 @@
+package dev.themeinerlp.attollo.listener
+
+import dev.themeinerlp.attollo.Attollo
+import org.bukkit.event.EventHandler
+import org.bukkit.event.Listener
+import org.bukkit.event.player.PlayerJoinEvent
+import java.net.URI
+
+class UpdateCheckerListener(private val attollo: Attollo) : Listener {
+
+    @EventHandler
+    fun onJoin(event: PlayerJoinEvent) {
+        val player = event.player
+        if (player.hasPermission("attollo.update")) {
+            attollo.server.scheduler.runTaskAsynchronously(attollo, Runnable {
+                val latestVersion = getLatestVersion()
+                if (attollo.description.version != latestVersion) {
+                    player.sendMessage(
+                        "§aAn update for Attollo is available! Version: $latestVersion",
+                        "§aYou can download it at: https://hangar.papermc.io/OneLiteFeather/Attollo"
+                    )
+                }
+            })
+        }
+    }
+
+    private fun getLatestVersion(): String {
+        val url = URI.create("https://hangar.papermc.io/api/v1/projects/Attollo/latestrelease").toURL()
+        val reader = url.openStream().bufferedReader()
+        val content = reader.use { it.readText() }
+        return content
+    }
+}