Implement invitations

src/main/kotlin/Invite.kt

@@ -0,0 +1,33 @@
+import org.bukkit.Bukkit
+import org.bukkit.OfflinePlayer
+import java.nio.ByteBuffer
+import java.util.*
+
+private val threadLocalBuffer = ThreadLocal.withInitial { ByteBuffer.allocate(32) }
+
+data class Invite(val recipient: OfflinePlayer, val portalID: UUID) {
+    private constructor(data: Pair<OfflinePlayer, UUID>): this(data.first, data.second)
+    constructor(data: String): this(parseData(data))
+    constructor(recipient: OfflinePlayer, portal: Portal): this(recipient, portal.id)
+
+    override fun toString(): String {
+        val buffer = threadLocalBuffer.get().position(0)
+        buffer.putLong(recipient.uniqueId.mostSignificantBits)
+        buffer.putLong(recipient.uniqueId.leastSignificantBits)
+        buffer.putLong(portalID.mostSignificantBits)
+        buffer.putLong(portalID.leastSignificantBits)
+
+        return Base64.getEncoder().withoutPadding().encodeToString(buffer.array())
+    }
+
+
+    companion object {
+        private fun parseData(data: String): Pair<OfflinePlayer, UUID> {
+            val buffer = threadLocalBuffer.get().position(0)
+
+            Base64.getDecoder().decode(data.toByteArray(Charsets.ISO_8859_1), buffer.array())
+
+            return Bukkit.getOfflinePlayer(UUID(buffer.long, buffer.long)) to UUID(buffer.long, buffer.long)
+        }
+    }
+}