1.1

.envrc

@@ -0,0 +1 @@
+use flake

.gitignore

@@ -21,3 +21,5 @@ gradle-app.setting
 # JDT-specific (Eclipse Java Development Tools)
 .classpath
 
+.direnv
+bin

README.md

@@ -1,2 +1,7 @@
 # Simply-minecraft-db
 
+## Features
+
+- [x] Configurable sharing options
+- [x] Store config to database
+- [x] Sync settings across multiple servers via a database

build.gradle.kts

@@ -1,7 +1,7 @@
 import net.minecrell.pluginyml.bukkit.BukkitPluginDescription
 
 group = "net.hareworks"
-version = "1.0"
+version = "1.1"
 
 val exposedVersion = "0.54.0"
 
@@ -9,14 +9,15 @@ plugins {
     kotlin("jvm") version "2.0.20"
     kotlin("plugin.serialization") version "2.0.20"
     id("net.minecrell.plugin-yml.bukkit") version "0.6.0"
-    id("com.github.johnrengelman.shadow") version "8.1.1"
+    id("com.gradleup.shadow") version "9.2.2"
 }
 repositories {
     mavenCentral()
     maven("https://repo.papermc.io/repository/maven-public/")
+    maven("https://repo.codemc.io/repository/maven-public/")
 }
 dependencies {
-    compileOnly("io.papermc.paper:paper-api:1.21.1-R0.1-SNAPSHOT")
+    compileOnly("io.papermc.paper:paper-api:1.21.10-R0.1-SNAPSHOT")
     implementation("net.kyori:adventure-api:4.17.0")
     implementation("net.kyori:adventure-text-minimessage:4.17.0")
     implementation("org.jetbrains.kotlinx:kotlinx-serialization-json:1.7.1")
@@ -26,11 +27,18 @@ dependencies {
     implementation("org.jetbrains.exposed:exposed-jdbc:$exposedVersion")
     implementation("org.jetbrains.kotlinx:kotlinx-datetime:0.6.1")
     implementation("org.jetbrains.exposed:exposed-kotlin-datetime:$exposedVersion")
+    implementation("de.tr7zw:item-nbt-api:2.15.3")
+    implementation("com.michael-bull.kotlin-result:kotlin-result:2.0.0")
 }
 tasks {
     shadowJar {
         archiveBaseName.set("SimplyMCDB")
         archiveClassifier.set("")
+        relocate("de.tr7zw.changeme.nbtapi", "net.hareworks.simplymcdb.libs.nbtapi")
+    }
+
+    build {
+        dependsOn(shadowJar)
     }
 }
 
@@ -39,11 +47,9 @@ bukkit {
     name = "Simply-Minecraft-DB"
     description = "It provides a simple way to manage player data through a database."
     version = getVersion().toString()
-		apiVersion = "1.21.1"
+		apiVersion = "1.21.10"
     authors =
-            listOf(
-                "Hare-K02",
-            )
+            listOf("Hare-K02")
     permissions {
         register("simplydb.*") {
             children = listOf("simplydb.command", "simplydb.admin")

flake.lock

@@ -0,0 +1,61 @@
+{
+  "nodes": {
+    "flake-utils": {
+      "inputs": {
+        "systems": "systems"
+      },
+      "locked": {
+        "lastModified": 1731533236,
+        "narHash": "sha256-l0KFg5HjrsfsO/JpG+r7fRrqm12kzFHyUHqHCVpMMbI=",
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "rev": "11707dc2f618dd54ca8739b309ec4fc024de578b",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "type": "github"
+      }
+    },
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1764020296,
+        "narHash": "sha256-6zddwDs2n+n01l+1TG6PlyokDdXzu/oBmEejcH5L5+A=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "a320ce8e6e2cc6b4397eef214d202a50a4583829",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixos-25.11",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "flake-utils": "flake-utils",
+        "nixpkgs": "nixpkgs"
+      }
+    },
+    "systems": {
+      "locked": {
+        "lastModified": 1681028828,
+        "narHash": "sha256-Vy1rq5AaRuLzOxct8nz4T6wlgyUR7zLU309k9mBC768=",
+        "owner": "nix-systems",
+        "repo": "default",
+        "rev": "da67096a3b9bf56a91d16901293e51ba5b49a27e",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-systems",
+        "repo": "default",
+        "type": "github"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}

flake.nix

@@ -0,0 +1,47 @@
+{
+  description = "Minecraft dev environment with JDK 21 and Gradle";
+
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/nixos-25.11";
+    flake-utils.url = "github:numtide/flake-utils";
+  };
+
+  outputs =
+    {
+      self,
+      nixpkgs,
+      flake-utils,
+      ...
+    }:
+    flake-utils.lib.eachDefaultSystem (
+      system:
+      let
+        pkgs = import nixpkgs {
+          inherit system;
+        };
+      in
+      {
+        devShells.default = pkgs.mkShell {
+          packages = with pkgs; [
+            jdk21
+            gradle
+            kotlin
+            git
+            unzip
+          ];
+
+          # 必要に応じて環境変数を設定
+          shellHook = ''
+            export JAVA_HOME=${pkgs.jdk21}/lib/openjdk
+            export PATH="$JAVA_HOME/bin:$PATH"
+
+            export GRADLE_USER_HOME="$PWD/.gradle"
+
+            echo "Loaded Minecraft dev env (JDK 21 + Gradle)"
+            java -version || true
+            gradle --version || true
+          '';
+        };
+      }
+    );
+}

gradle/gradle-daemon-jvm.properties

@@ -0,0 +1,2 @@
+#This file is generated by updateDaemonJvm
+toolchainVersion=21

gradle/wrapper/gradle-wrapper.properties

@@ -1,6 +1,7 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-8.10.1-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.14-bin.zip
 networkTimeout=10000
+validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists

gradlew

@@ -15,6 +15,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 #
+# SPDX-License-Identifier: Apache-2.0
+#
 
 ##############################################################################
 #
@@ -55,7 +57,7 @@
 #       Darwin, MinGW, and NonStop.
 #
 #   (3) This script is generated from the Groovy template
-#       https://github.com/gradle/gradle/blob/HEAD/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       https://github.com/gradle/gradle/blob/HEAD/platforms/jvm/plugins-application/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
 #       within the Gradle project.
 #
 #       You can find Gradle at https://github.com/gradle/gradle/.
@@ -83,10 +85,9 @@ done
 # This is normally unused
 # shellcheck disable=SC2034
 APP_BASE_NAME=${0##*/}
-APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
-
-# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+# Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
+APP_HOME=$( cd -P "${APP_HOME:-./}" > /dev/null && printf '%s
+' "$PWD" ) || exit
 
 # Use the maximum available, or set MAX_FD != -1 to use that value.
 MAX_FD=maximum
@@ -133,10 +134,13 @@ location of your Java installation."
     fi
 else
     JAVACMD=java
-    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+    if ! command -v java >/dev/null 2>&1
+    then
+        die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
 
 Please set the JAVA_HOME variable in your environment to match the
 location of your Java installation."
+    fi
 fi
 
 # Increase the maximum file descriptors if we can.
@@ -144,7 +148,7 @@ if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
     case $MAX_FD in #(
       max*)
         # In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
-        # shellcheck disable=SC3045
+        # shellcheck disable=SC2039,SC3045
         MAX_FD=$( ulimit -H -n ) ||
             warn "Could not query maximum file descriptor limit"
     esac
@@ -152,7 +156,7 @@ if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
       '' | soft) :;; #(
       *)
         # In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
-        # shellcheck disable=SC3045
+        # shellcheck disable=SC2039,SC3045
         ulimit -n "$MAX_FD" ||
             warn "Could not set maximum file descriptor limit to $MAX_FD"
     esac
@@ -197,11 +201,15 @@ if "$cygwin" || "$msys" ; then
     done
 fi
 
-# Collect all arguments for the java command;
-#   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
-#     shell script including quotes and variable substitutions, so put them in
-#     double quotes to make sure that they get re-expanded; and
-#   * put everything else in single quotes, so that it's not re-expanded.
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Collect all arguments for the java command:
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, JAVA_OPTS, and optsEnvironmentVar are not allowed to contain shell fragments,
+#     and any embedded shellness will be escaped.
+#   * For example: A user cannot expect ${Hostname} to be expanded, as it is an environment variable and will be
+#     treated as '${Hostname}' itself on the command line.
 
 set -- \
         "-Dorg.gradle.appname=$APP_BASE_NAME" \

gradlew.bat

@@ -13,6 +13,8 @@
 @rem See the License for the specific language governing permissions and
 @rem limitations under the License.
 @rem
+@rem SPDX-License-Identifier: Apache-2.0
+@rem
 
 @if "%DEBUG%"=="" @echo off
 @rem ##########################################################################
@@ -43,11 +45,11 @@ set JAVA_EXE=java.exe
 %JAVA_EXE% -version >NUL 2>&1
 if %ERRORLEVEL% equ 0 goto execute
 
-echo.
-echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -57,11 +59,11 @@ set JAVA_EXE=%JAVA_HOME%/bin/java.exe
 
 if exist "%JAVA_EXE%" goto execute
 
-echo.
-echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME% 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 

src/main/kotlin/net/hareworks/kommandlib/main.kt

@@ -1,5 +1,6 @@
 package net.hareworks.kommandlib
 
+import com.github.michaelbull.result.*
 import kotlin.collections.listOf
 import org.bukkit.Bukkit
 import org.bukkit.command.CommandMap
@@ -7,47 +8,52 @@ import org.bukkit.command.CommandSender
 import org.bukkit.command.PluginCommand
 import org.bukkit.command.TabCompleter
 import org.bukkit.plugin.java.JavaPlugin
+import net.hareworks.simplymcdb.App
 
-class KommandLib(plugin: JavaPlugin, vararg routes: Pair<String, Argument>) {
-  val routes = routes.toMap()
+class KommandLib(plugin: JavaPlugin, vararg routes: Argument) {
+  val entries = routes.toList()
   init {
     val f = Bukkit.getServer().javaClass.getDeclaredField("commandMap")
     f.isAccessible = true
     val commandMap = f.get(Bukkit.getServer()) as CommandMap
-    for ((name, _) in routes) {
+    for (route in routes) {
       commandMap.register(
-          plugin.getName(),
-          (PluginCommand::class
-                  .java
-                  .declaredConstructors
-                  .first()
-                  .apply { isAccessible = true }
-                  .newInstance(name, plugin) as
-                  PluginCommand)
-              .apply {
-                this.name = name
-                this.setExecutor { sender, _, alias, args ->
-                  val route = getLastRoute(arrayOf(alias, *args))
-                  if (route.size == args.size + 1) route.last().onCommand(sender, args)
-                  true
-                }
-                this.tabCompleter = TabCompleter { sender, _, alias, args ->
-                  val route = getLastRoute(arrayOf(alias, *args))
-                  if (route.size == args.size) route.last().getCompletList(sender, args)
-                  else listOf()
-                }
-              }
+              plugin.getName(),
+              (PluginCommand::class
+                              .java
+                              .declaredConstructors
+                              .first()
+                              .apply { isAccessible = true }
+                              .newInstance(route.name, plugin) as
+                              PluginCommand)
+                      .apply {
+                        this.name = name
+                        this.setExecutor { sender, _, alias, args ->
+                          val routeargs = routeTreeSearch(arrayOf(alias, *args))
+                          if (routeargs.size == args.size + 1)
+                                  routeargs.last().onCommand(sender, args)
+                          true
+                        }
+                        this.tabCompleter = TabCompleter { sender, _, alias, args ->
+                          val routeargs = routeTreeSearch(arrayOf(alias, *args))
+                          if (routeargs.size == args.size)
+                                  routeargs.last().getCompletList(sender, args)
+                          else listOf()
+                        }
+                      }
       )
     }
   }
 
-  fun getLastRoute(args: Array<String>): List<Argument> {
-    val list = mutableListOf<Argument>(routes[args[0]] ?: throw Exception("Invalid command"))
+  fun routeTreeSearch(args: Array<String>): List<Argument> {
+    val list =
+            mutableListOf<Argument>(
+                    entries.find { it.name == args[0] } ?: throw Exception("Invalid command")
+            )
     var i = 1
     while (i + 1 <= args.size) {
       if (list.last().routes.isEmpty()) break
-      val route =
-          list.last().routes.values.sortedBy { it.priority }.find { it.typeCheck(args[i]) } ?: break
+      val route = list.last().routes.sortedBy { it.priority }.find { it.name == args[i] } ?: break
       list.add(route)
       i += route.unit
     }
@@ -58,127 +64,82 @@ class KommandLib(plugin: JavaPlugin, vararg routes: Pair<String, Argument>) {
     val f = Bukkit.getServer().javaClass.getDeclaredField("commandMap")
     f.isAccessible = true
     val commandMap = f.get(Bukkit.getServer()) as CommandMap
-    for ((name, _) in routes) {
-      commandMap.getCommand(name)?.unregister(commandMap)
+    for (route in entries) {
+      commandMap.getCommand(route.name)?.unregister(commandMap)
     }
   }
 }
 
 abstract class Argument(
-    vararg routes: Pair<String, Argument>,
-    val execute: (CommandSender, Array<Any>) -> Unit
+        val argname: String,
+        vararg routes: Argument,
+        val execute: (CommandSender, Array<String>) -> Unit
 ) {
-  val routes = routes.toMap()
-  var name: String = ""
+  val name = argname
+  var routes = routes.toList()
   var permission: String = ""
     set(value) {
       field = value
       if (value.isEmpty()) return
-      for ((_, route) in routes) {
+      for (route in routes) {
         route.permission = value + "." + route.name
       }
-      println("permission setted to $value")
     }
-    var condition: (CommandSender) -> Boolean = { true }
+  var condition: (CommandSender) -> Boolean = { true }
 
-  init {
-    for ((name, route) in routes) {
-      route.name = name
-    }
+  public fun addArgs(vararg routes: Argument): Argument {
+    this.routes += routes
+    return this
   }
 
   abstract var priority: Int
   open var unit: Int = 1
-  abstract fun onCommand(sender: CommandSender, args: Array<String>)
-  abstract fun typeCheck(arg: String): Boolean
-  abstract fun toValue(args: Array<String>): Any
+  open fun onCommand(sender: CommandSender, args: Array<String>) {
+    execute(sender, args)
+  }
 
   abstract fun suggest(sender: CommandSender, args: Array<String>): List<String>
 
   fun getCompletList(sender: CommandSender, args: Array<String>): List<String> {
     return routes
-        .values
-        .filter { sender.hasPermission(it.permission) && it.condition(sender) }
-        .map { it.suggest(sender, args) }
-        .flatten()
+            .filter { sender.hasPermission(it.permission) && it.condition(sender) }
+            .map { it.suggest(sender, args) }
+            .flatten()
   }
 }
 
-class Route(vararg routes: Pair<String, Argument>, execute: (CommandSender, Array<Any>) -> Unit) :
-    Argument(*routes, execute = execute) {
+class Route(
+        name: String,
+        vararg routes: Argument,
+        execute: (CommandSender, Array<String>) -> Unit
+) : Argument(name, *routes, execute = execute) {
   override var priority: Int = 2
-  override fun onCommand(sender: CommandSender, args: Array<String>) {
-    execute(sender, args.map { it }.toTypedArray())
-  }
-  override fun typeCheck(arg: String): Boolean {
-    return this.name == arg
-  }
-  override fun toValue(args: Array<String>): Any {
-    return args.joinToString(" ")
-  }
 
   override fun suggest(sender: CommandSender, args: Array<String>): List<String> {
-    return if (sender.hasPermission(this.permission) && this.condition(sender) && this.name.startsWith(args.last()))
-        listOf(this.name)
+    return if (sender.hasPermission(this.permission) &&
+                    this.condition(sender) &&
+                    this.name.startsWith(args.last())
+    )
+            listOf(this.name)
     else listOf()
   }
 }
 
-class Text(vararg routes: Pair<String, Argument>, execute: (CommandSender, Array<Any>) -> Unit) :
-    Argument(*routes, execute = execute) {
+class Text(name: String, vararg routes: Argument, execute: (CommandSender, Array<String>) -> Unit) :
+        Argument(name, *routes, execute = execute) {
   override var priority: Int = 0
-  override fun typeCheck(arg: String): Boolean {
-    return true
-  }
-  override fun toValue(args: Array<String>): Any {
-    return args.joinToString(" ")
-  }
-  override fun onCommand(sender: CommandSender, args: Array<String>) {
-    execute(sender, args.map { it }.toTypedArray())
-  }
 
   override fun suggest(sender: CommandSender, args: Array<String>): List<String> {
     return listOf(args.last())
   }
 }
 
-class Integer(vararg routes: Pair<String, Argument>, execute: (CommandSender, Array<Any>) -> Unit) :
-    Argument(*routes, execute = execute) {
+class Integer(
+        name: String,
+        vararg routes: Argument,
+        execute: (CommandSender, Array<String>) -> Unit
+) : Argument(name, *routes, execute = execute) {
   override var priority: Int = 1
-  override fun typeCheck(arg: String): Boolean {
-    return arg.toIntOrNull() != null
-  }
-
-  override fun onCommand(sender: CommandSender, args: Array<String>) {
-    execute(sender, args.map { it.toInt() }.toTypedArray())
-  }
-
-  override fun toValue(args: Array<String>): Any {
-    return args[0].toInt()
-  }
-
-  override fun suggest(sender: CommandSender, args: Array<String>): List<String> {
-    return listOf()
-  }
-}
-
-class Position(
-    vararg routes: Pair<String, Argument>,
-    execute: (CommandSender, Array<Any>) -> Unit
-) : Argument(*routes, execute = execute) {
-  override var priority: Int = 3
-  override var unit: Int = 3
-  override fun typeCheck(arg: String): Boolean {
-    return true
-  }
-
-  override fun onCommand(sender: CommandSender, args: Array<String>) {
-    execute(sender, args.map { it }.toTypedArray())
-  }
-
-  override fun toValue(args: Array<String>): Any {
-    return Triple(args[0].toDouble(), args[1].toDouble(), args[2].toDouble())
-  }
 
   override fun suggest(sender: CommandSender, args: Array<String>): List<String> {
     return listOf()

src/main/kotlin/net/hareworks/simplymcdb/App.kt

@@ -1,11 +1,11 @@
 package net.hareworks.simplymcdb
 
-import net.hareworks.simplymcdb.Config
-import net.hareworks.simplymcdb.database.Database
-import net.hareworks.simplymcdb.command.smcdb
 import net.hareworks.kommandlib.KommandLib
+import net.hareworks.simplymcdb.command.smcdb
+import net.hareworks.simplymcdb.database.Database
 import org.bukkit.plugin.java.JavaPlugin
 
+
 enum class State {
   ACTIVE,
   DISCONNECTED,
@@ -18,19 +18,25 @@ public class App : JavaPlugin() {
       field = value
       Config.config.set("enabled", !value.equals(State.DISABLED))
     }
+
   companion object {
     lateinit var instance: App
       private set
   }
+
   lateinit var command: KommandLib
     private set
+
   override fun onEnable() {
     instance = this
-    logger.info("simplymcdb enabled.")
-
     Config.init()
-    command = KommandLib(this, "smcdb" to smcdb)
+    command = KommandLib(this, smcdb)
+
+    server.pluginManager.registerEvents(EventListener, this)
+
+    if (Config.check()) enable()
   }
+
   override fun onDisable() {
     enabled = State.DISABLED
     Database.disconnect()

src/main/kotlin/net/hareworks/simplymcdb/Command.kt

@@ -1,119 +1,287 @@
 package net.hareworks.simplymcdb.command
 
+import com.github.michaelbull.result.*
 import net.hareworks.kommandlib.*
-import net.hareworks.simplymcdb.App
-import net.hareworks.simplymcdb.State
-import net.hareworks.simplymcdb.config.reload as reloadConfig
+import net.hareworks.simplymcdb.*
 import net.hareworks.simplymcdb.database.Database
+import net.kyori.adventure.audience.Audience
 import net.kyori.adventure.text.minimessage.MiniMessage
+import org.bukkit.entity.Player
 
-public val smcdb: Route =
-  Route(
-      "config" to
-        Route(
-            "reload" to
-              Route { sender, _ ->
-                sender.sendMessage("reloading config...")
-                reloadConfig()
-                sender.sendMessage("reloaded.")
-              }
-                .apply {
-                  permission =
-                    "simplydb.command.config.reload"
-                },
-            "fetch" to
-              Route { sender, _ ->
-                sender.sendMessage("fetching config...")
-              }
-                .apply {
-                  permission =
-                    "simplydb.command.config.fetch"
-                },
-            "upload" to
-              Route { sender, _ ->
-                sender.sendMessage("uploading config...")
-              }
-                .apply {
-                  permission =
-                    "simplydb.command.config.upload"
-                },
-            "help" to
-              Route { sender, _ ->
-                var help =
-                  MiniMessage.miniMessage()
-                    .deserialize(
-                      "<red>simplymcdb config help<newline><gray>reload: <green>reload the config from config.yml<newline><gray>fetch: <green>fetch the config from the database<newline><gray>upload: <green>upload the current config to the database"
-                    )
-                sender.sendMessage(help)
-              }
-                .apply {
-                  permission =
-                    "simplydb.command.config"
-                },
-            "on" to
-              Route { sender, _ ->
-                if (App.instance.enabled == State.ACTIVE
-                ) {
-                  sender.sendMessage(
-                    "simplymcdb is already enabled."
-                  )
-                  return@Route
-                }
-                App.instance.enable()
-                sender.sendMessage("simplymcdb enabled.")
-              }
-                .apply {
-                  permission = "simplydb.command.config.on"
-                },
-            "off" to
-              Route { sender, _ ->
-                if (App.instance.enabled != State.ACTIVE
-                ) {
-                  sender.sendMessage(
-                    "simplymcdb is already disabled."
-                  )
-                  return@Route
-                }
-                App.instance.disable()
-                sender.sendMessage("simplymcdb disabled.")
-              }
-                .apply {
-                  permission =
-                    "simplydb.command.config.off"
-                },
-          ) { sender, _ ->
-          (sender as   ).performCommand("smcdb config help")
-        }
-          .apply { permission = "simplydb.command.config" },
-      "help" to Route { sender, _ ->
-        var help =
-          MiniMessage.miniMessage()
-            .deserialize(
-              "<red>simplymcdb help<newline><gray>config: <green>configre the plugin<newline><gray>activate: <green>when the plugin is disabled, activate it<newline><gray>deactivate: <green>when the plugin is enabled, deactivate it"
-            )
-        sender.sendMessage(help)
-      }
-        .apply { permission = "simplydb.command" },
-      "activate" to Route { sender, _ ->
-        if (App.instance.enabled == State.ACTIVE
-        ) {
-          sender.sendMessage(
-            "simplymcdb is already enabled."
-          )
-          return@Route
-        }
-        App.instance.enable()
-        sender.sendMessage("simplymcdb enabled.")
-      }
-        .apply { permission = "simplydb.command.activate" },
-      "initialize" to Route { sender, _ ->
-        sender.sendMessage("database initializing...")
-        Database.initialize()
-      }
-        .apply { permission = "simplydb.command.setup" },
-      "confirm" to Route { sender, _ ->
-        
-      }
-        .apply { permission = "simplydb.command.confirm" },
-    ) { sender, _ -> sender.sendMessage("simplymcdb command") }
-    .apply { name = "simplymcdb" }
+public fun Audience.sendMM(message: String) {
+  this.sendMessage(MiniMessage.miniMessage().deserialize(message))
+}
+
+val command_buffer = mutableMapOf<java.util.UUID, String>()
+public val smcdb =
+        Route("smcdb") { sender, _ -> sender.sendMessage("simptlymcdb command") }
+                .addArgs(
+                        Route("config") { sender, _ ->
+                                  (sender as Player).performCommand("smcdb config help")
+                                }
+                                .addArgs(
+                                        Route("reload") { sender, _ ->
+                                          sender.sendMessage("reloading config...")
+                                          Config.reload()
+                                          sender.sendMessage("reloaded.")
+                                        },
+                                        Route("fetch") { sender, _ ->
+                                          sender.sendMessage("fetching config...")
+                                        },
+                                        Route("upload") { sender, _ ->
+                                          sender.sendMessage("uploading config...")
+                                        },
+                                        Route("help") { sender, _ ->
+                                          var help =
+                                                  MiniMessage.miniMessage()
+                                                          .deserialize(
+                                                                  "<red>simplymcdb config help<newline><gray>reload: <green>reload the config from config.yml<newline><gray>fetch: <green>fetch the config from the database<newline><gray>upload: <green>upload the current config to the database"
+                                                          )
+                                          sender.sendMessage(help)
+                                        }
+                                ),
+                        Route("help") { sender, _ ->
+                          sender.sendMM(
+                                  "<red>simplymcdb help<newline><gray>config: <green>configre the plugin<newline><gray>activate: <green>when the plugin is disabled, activate it<newline><gray>deactivate: <green>when the plugin is enabled, deactivate it"
+                          )
+                        },
+                        Route("activate") { sender, _ ->
+                          if (App.instance.enabled == State.ACTIVE) {
+                            sender.sendMessage("simplymcdb is already enabled.")
+                            return@Route
+                          }
+                          App.instance.enable()
+                          sender.sendMessage("simplymcdb enabled.")
+                        },
+                        Route("deactivate") { sender, _ ->
+                          if (App.instance.enabled == State.DISABLED) {
+                            sender.sendMessage("simplymcdb is already disabled.")
+                            return@Route
+                          }
+                          App.instance.disable()
+                          sender.sendMessage("simplymcdb disabled.")
+                        },
+                        Route("database") { _, _ -> }
+                                .addArgs(
+                                        Route("init") { sender, _ ->
+                                          Database.initialize()
+                                          sender.sendMessage("database initialized.")
+                                        },
+                                        Route("reset") { sender, _ ->
+                                          Database.reset()
+                                          sender.sendMessage("database reset.")
+                                        },
+                                ),
+                        Route("migrate") { sender, _ ->
+                          if (sender !is Player) {
+                            sender.sendMM("<red>[SMCDB] This command can only be run by players.")
+                            return@Route
+                          }
+                          when (App.instance.enabled) {
+                            State.DISABLED -> {
+                              sender.sendMM("<red>[SMCDB] simplymcdb is disabled.")
+                              return@Route
+                            }
+                            State.DISCONNECTED -> {
+                              sender.sendMM("<yellow>[SMCDB] Database disconnected. Try again later.")
+                              return@Route
+                            }
+                            else -> {}
+                          }
+                          if (!isRegistered(sender.uniqueId)) {
+                            sender.sendMM("<red>[SMCDB] You are not registered in the database.")
+                            return@Route
+                          }
+                          try {
+                            sender.sendMM("<gray>[SMCDB] Applying legacy data...")
+                            fetch(sender)
+                            update(sender)
+                            sender.sendMM("<green>[SMCDB] Migration complete. Data updated to the latest format.")
+                          } catch (e: Exception) {
+                            App.instance.logger.warning("Failed to migrate data for ${sender.uniqueId}: ${e.message}")
+                            sender.sendMM("<red>[SMCDB] Migration failed. Check server logs.")
+                          }
+                        }.addArgs(
+                                Route("all") { sender, _ ->
+                                  if (sender !is Player) {
+                                    sender.sendMM("<red>[SMCDB] This command can only be run by players.")
+                                    return@Route
+                                  }
+                                  when (App.instance.enabled) {
+                                    State.DISABLED -> {
+                                      sender.sendMM("<red>[SMCDB] simplymcdb is disabled.")
+                                      return@Route
+                                    }
+                                    State.DISCONNECTED -> {
+                                      sender.sendMM(
+                                              "<yellow>[SMCDB] Database disconnected. Try again later."
+                                      )
+                                      return@Route
+                                    }
+                                    else -> {}
+                                  }
+                                  val targets = findPlayersNeedingMigration()
+                                  if (targets.isEmpty()) {
+                                    sender.sendMM("<gray>[SMCDB] No legacy data found.")
+                                    return@Route
+                                  }
+                                  sender.sendMM(
+                                          "<gray>[SMCDB] Migrating ${targets.size} legacy profiles... Please wait."
+                                  )
+                                  val backup = PlayerSerializer.serialize(sender)
+                                  var migrated = 0
+                                  try {
+                                    targets.forEach { entry ->
+                                      try {
+                                        PlayerSerializer.deserialize(sender, entry.serialized)
+                                        val updatedSnapshot = PlayerSerializer.serialize(sender)
+                                        overwritePlayerData(entry.uuid, updatedSnapshot)
+                                        migrated++
+                                      } catch (ex: Exception) {
+                                        App.instance.logger.warning(
+                                                "Failed to migrate data for ${entry.uuid}: ${ex.message}"
+                                        )
+                                      }
+                                    }
+                                  } finally {
+                                    try {
+                                      PlayerSerializer.deserialize(sender, backup)
+                                    } catch (restoreEx: Exception) {
+                                      App.instance.logger.warning(
+                                              "Failed to restore migration executor state: ${restoreEx.message}"
+                                      )
+                                    }
+                                  }
+                                  sender.sendMM(
+                                          "<green>[SMCDB] Migration finished ($migrated/${targets.size}). Check logs for failures."
+                                  )
+                                }
+                        ),
+                        Route("check") { sender, _ ->
+                          sender.sendMM(
+                                  "${when (App.instance.enabled) {
+                                              State.ACTIVE -> "<green>●"
+                                              State.DISCONNECTED -> "<yellow>■"
+                                              State.DISABLED -> "<red>○"
+                                            }}<white> simply-minecraft-database"
+                          )
+                          sender.sendMM(
+                                  "status: ${when (App.instance.enabled) {
+                                                          State.ACTIVE -> "<green>active" 
+                                                          State.DISCONNECTED -> "<yellow>disconnected"
+                                                          State.DISABLED -> "<red>disabled"}}"
+                          )
+                          sender.sendMM(
+                                  "<gray>- <white>database test: ${if (Database.ping()) "success" else "failed"}"
+                          )
+                          sender.sendMM(
+                                  "<gray>- <white>config test: ${if (Config.config.getBoolean("enabled")) "enabled" else "disabled"}"
+                          )
+                        },
+                        Route("register") { sender, _ ->
+                          if (sender !is Player) {
+                            sender.sendMM("This command is only available for players.")
+                            return@Route
+                          } else
+                                  when (App.instance.enabled) {
+                                    State.DISABLED ->
+                                            sender.sendMM(
+                                                    "<red>[SMCDB] simplymcdb is disabled.<br>Run /smcdb check to check the status."
+                                            )
+                                    State.DISCONNECTED ->
+                                            sender.sendMM(
+                                                    "<red>[SMCDB] simplymcdb is enabled but disconnected.<br>Run /smcdb check to check the status."
+                                            )
+                                    else -> {
+                                      if (!isRegistered(sender.uniqueId)) {
+                                        sender.sendMM(
+                                                "<gray>[SMCDB] <red>The inventory of the other servers will be overwritten.<newline>" +
+                                                        "Are you sure you want to register?<newline>" +
+                                                        "<green>/smcdb confirm<gray> to confirm."
+                                        )
+                                      } else {
+                                        sender.sendMM("<gray>[SMCDB] You are already registered.")
+                                      }
+                                    }
+                                  }
+                        },
+                        Route("confirm") { sender, _ ->
+                          if (sender !is Player) return@Route
+                          when (command_buffer[sender.uniqueId]) {
+                            "register" -> {
+                              if (App.instance.enabled == State.ACTIVE) {
+                                register(sender)
+                                sender.sendMM("<gray>[SMCDB] Successfully registered.")
+                              } else {
+                                sender.sendMM("<red>[SMCDB] simplymcdb is disabled.")
+                              }
+                            }
+                            else -> {
+                              sender.sendMM("<red>[SMCDB] Invalid command.")
+                            }
+                          }
+                          command_buffer.remove(sender.uniqueId)
+                        }
+                        // Route("update") { sender, _ ->
+                        //   if (sender !is Player) {
+                        //     sender.sendMM("This command is only available for players.")
+                        //     return@Route
+                        //   } else
+                        //           when (App.instance.enabled) {
+                        //             State.DISABLED ->
+                        //                     sender.sendMM(
+                        //                             "<red>[SMCDB] simplymcdb is disabled.<br>Run
+                        // /smcdb check to check the status."
+                        //                     )
+                        //             State.DISCONNECTED ->
+                        //                     sender.sendMM(
+                        //                             "<red>[SMCDB] simplymcdb is enabled but
+                        // disconnected.<br>Run /smcdb check to check the status."
+                        //                     )
+                        //             else -> {
+                        //               if (isRegistered(sender.uniqueId)) {
+                        //                 update(sender)
+                        //                 sender.sendMM("<gray>[SMCDB] Successfully updated.")
+                        //               } else {
+                        //                 sender.sendMM("<red>[SMCDB] You are not registered.")
+                        //               }
+                        //             }
+                        //           }
+                        // },
+                        // Route("fetch") { sender, _ ->
+                        //   if (sender !is Player) {
+                        //     sender.sendMM("This command is only available for players.")
+                        //     return@Route
+                        //   } else
+                        //           when (App.instance.enabled) {
+                        //             State.DISABLED ->
+                        //                     sender.sendMM(
+                        //                             "<red>[SMCDB] simplymcdb is disabled.<br>Run
+                        // /smcdb check to check the status."
+                        //                     )
+                        //             State.DISCONNECTED ->
+                        //                     sender.sendMM(
+                        //                             "<red>[SMCDB] simplymcdb is enabled but
+                        // disconnected.<br>Run /smcdb check to check the status."
+                        //                     )
+                        //             else -> {
+                        //               if (isRegistered(sender.uniqueId)) {
+                        //                 sender.sendMM(
+                        //                         "<gray>[SMCDB] Welcome back,
+                        // ${sender.name}.<newline>Fetching your data..."
+                        //                 )
+                        //                 fetch(sender)
+                        //               } else {
+                        //                 sender.sendMM(
+                        //                         "<gray>[SMCDB] Welcome, ${sender.name}.<newline>"
+                        // +
+                        //                                 "SMCDB is active but you have already
+                        // played before.<newline>" +
+                        //                                 "Run <green>/smcdb register<gray> to
+                        // register yourself."
+                        //                 )
+                        //               }
+                        //             }
+                        //           }
+                        // },
+                        )

src/main/kotlin/net/hareworks/simplymcdb/Config.kt

@@ -3,7 +3,6 @@ package net.hareworks.simplymcdb
 import org.bukkit.configuration.file.YamlConfiguration
 import org.jetbrains.exposed.sql.Table
 
-
 object ConfigTable : Table() {
   val uuid = varchar("uuid", 36)
   val name = varchar("name", 16)
@@ -34,4 +33,8 @@ public object Config {
     config.save(App.instance.dataFolder.resolve("config.yml"))
     App.instance.logger.info("config saved.")
   }
+
+  public fun check(): Boolean {
+    return config.getBoolean("enabled")
+  }
 }

src/main/kotlin/net/hareworks/simplymcdb/Event.kt

@@ -1,14 +1,11 @@
-package net.hareworks.simplymcdb.event
+package net.hareworks.simplymcdb
 
-import net.hareworks.simplymcdb.App
-import net.hareworks.simplymcdb.State
-import net.hareworks.simplymcdb.database.Database
 import net.kyori.adventure.text.minimessage.MiniMessage
 import org.bukkit.event.EventHandler
 import org.bukkit.event.Listener
 import org.bukkit.event.player.PlayerJoinEvent
+import org.bukkit.event.player.PlayerQuitEvent
 import org.jetbrains.exposed.sql.*
-import org.jetbrains.exposed.sql.transactions.transaction
 
 public object EventListener : Listener {
   @EventHandler
@@ -16,27 +13,53 @@ public object EventListener : Listener {
     if (event.player.hasPermission("simplymcdb.admin")) {
       when (App.instance.enabled) {
         State.DISABLED -> {
-          val mm = MiniMessage.miniMessage().deserialize("<red>simplymcdb is disabled.")
+          val mm =
+                  MiniMessage.miniMessage()
+                          .deserialize(
+                                  "<red>[SMCDB:admin] simplymcdb is disabled.<br>Run /smcdb check to check the status."
+                          )
           event.player.sendMessage(mm)
         }
         State.DISCONNECTED -> {
-          val mm = MiniMessage.miniMessage().deserialize("<red>simplymcdb is enabled but disconnected.<br><gray>Check the database connection and try /smcdb on.")
+          val mm =
+                  MiniMessage.miniMessage()
+                          .deserialize(
+                                  "<red>[SMCDB:admin] simplymcdb is enabled but disconnected.<br>Run /smcdb check to check the status."
+                          )
           event.player.sendMessage(mm)
         }
         else -> {
-          val mm = MiniMessage.miniMessage().deserialize("<green>simplymcdb is enabled.")
+          val mm =
+                  MiniMessage.miniMessage()
+                          .deserialize("<green>[SMCDB:admin] simplymcdb is enabled.")
           event.player.sendMessage(mm)
         }
       }
     }
-    if (App.instance.enabled == State.ACTIVE) {
-      val player = event.player
-      // if player has already registered in the database, load the data
-      Database.instance?.let {
-        transaction(it) {
-          
-        }
-      }
-    }
+
+    if (App.instance.enabled !== State.ACTIVE) return
+
+    /*-----------+-------------------+
+    |            | played     not    |
+    +------------+-------------------+
+    | registered |  fetch    fetch   |
+    |    not     | confirm  register |
+    +------------+------------------*/
+    if (isRegistered(event.player.uniqueId)) fetch(event.player)
+    else if (event.player.hasPlayedBefore()) register(event.player)
+    else event.player.sendMessage(
+      MiniMessage.miniMessage()
+        .deserialize(
+          "<gray>[SMCDB] Welcome, ${event.player.name}.<newline>" +
+          "SMCDB is active but you have already played before.<newline>" +
+          "Run <green>/smcdb register<gray> to register yourself."
+      )
+    )
+  }
+
+  @EventHandler
+  fun onQuit(event: PlayerQuitEvent) {
+    if (App.instance.enabled !== State.ACTIVE) return
+    if (isRegistered(event.player.uniqueId)) update(event.player)
   }
 }

src/main/kotlin/net/hareworks/simplymcdb/PlayerData.kt

@@ -1,49 +0,0 @@
-package net.hareworks.simplymcdb.playerdata
-
-import net.hareworks.simplymcdb.App
-import net.hareworks.simplymcdb.database.Database
-import org.bukkit.entity.Player as BukkitPlayer
-import org.jetbrains.exposed.sql.*
-import org.jetbrains.exposed.sql.transactions.transaction
-
-public object Player : Table() {
-  val uuid = varchar("uuid", 36)
-  val name = varchar("name", 16)
-  val lastLogin = long("last_login")
-  val lastLogout = long("last_logout")
-  val playTime = long("play_time")
-  val firstLogin = long("first_login")
-  val lastIp = varchar("last_ip", 15)
-
-  val data = text("data").nullable()
-
-  override val primaryKey = PrimaryKey(uuid)
-}
-
-public fun register(player: BukkitPlayer) {
-  App.instance.logger.info("Registering player data for ${player.name}")
-  Database.instance?.let {
-    transaction {
-      Player.insert {
-        it[uuid] = player.uniqueId.toString()
-        it[name] = player.name
-        it[lastLogin] = System.currentTimeMillis()
-        it[firstLogin] = System.currentTimeMillis()
-        it[lastIp] = player.address?.address?.hostAddress ?: "unknown"
-      }
-    }
-  }
-}
-
-public fun push(player: BukkitPlayer) {
-  App.instance.logger.info("Creating player data for ${player.name}")
-  Database.instance?.let {
-    transaction {
-      Player.update({ Player.uuid eq player.uniqueId.toString() }) {
-        it[lastLogin] = System.currentTimeMillis()
-        it[lastIp] = player.address?.address?.hostAddress ?: "unknown"
-        
-      }
-    }
-  }
-}

src/main/kotlin/net/hareworks/simplymcdb/PlayerSerializer.kt

@@ -1,31 +1,179 @@
 package net.hareworks.simplymcdb
 
+import de.tr7zw.changeme.nbtapi.NBT
+import java.util.Base64
+import java.util.function.Function
+import io.papermc.paper.registry.RegistryAccess
+import io.papermc.paper.registry.RegistryKey
+import kotlinx.serialization.Serializable
+import kotlinx.serialization.SerializationException
+import kotlinx.serialization.json.Json
+import org.bukkit.NamespacedKey
+import org.bukkit.Registry
+import org.bukkit.attribute.Attribute
 import org.bukkit.entity.Player as BukkitPlayer
 import org.bukkit.inventory.ItemStack
+import org.bukkit.potion.PotionEffect
+import org.bukkit.potion.PotionEffectType
 
-class PlayerInventory(
-  val contents: Array<ItemStack>,
-  val armor: Array<ItemStack>,
+const val PLAYER_DATA_CURRENT_VERSION = 1
+
+@Serializable
+data class PlayerSnapshot(
+        val version: Int = PLAYER_DATA_CURRENT_VERSION,
+        val health: Double,
+        val foodLevel: Int,
+        val xpProgress: Float,
+        val selectedItemSlot: Int,
+        val potionEffects: List<PotionEffectSnapshot>,
+        val inventory: List<ItemStackSnapshot?>,
+        val enderChest: List<ItemStackSnapshot?>
 )
 
+@Serializable
+data class PotionEffectSnapshot(
+        val type: String,
+        val amplifier: Int,
+        val duration: Int,
+        val ambient: Boolean,
+        val particles: Boolean,
+        val icon: Boolean
+)
+
+@Serializable data class ItemStackSnapshot(val payload: String)
+
+private val json =
+        Json {
+          encodeDefaults = true
+          ignoreUnknownKeys = true
+        }
+private val mobEffectRegistry: Registry<PotionEffectType>?
+  get() = RegistryAccess.registryAccess().getRegistry(RegistryKey.MOB_EFFECT)
+
 object PlayerSerializer {
   fun serialize(player: BukkitPlayer): String {
-    val inv = player.inventory.storageContents
-    val armor = player.inventory.armorContents
-    val enderChest = player.enderChest
-
-    return "" // base64 encoded string
+    val snapshot =
+            PlayerSnapshot(
+                    health = player.health,
+                    foodLevel = player.foodLevel,
+                    xpProgress = player.exp,
+                    selectedItemSlot = player.inventory.heldItemSlot,
+                    potionEffects = player.activePotionEffects.map(::serializePotionEffect),
+                    inventory = player.inventory.contents.map { it?.let(::serializeItemStack) },
+                    enderChest = player.enderChest.contents.map { it?.let(::serializeItemStack) }
+            )
+    return json.encodeToString(PlayerSnapshot.serializer(), snapshot)
   }
 
-  fun deserialize(data: String): Map<String, Any> {
-    return mapOf()
+  fun deserialize(player: BukkitPlayer, data: String) {
+    val snapshot =
+            try {
+              json.decodeFromString(PlayerSnapshot.serializer(), data)
+            } catch (ex: SerializationException) {
+              if (LegacySerializer.deserialize(player, data)) return else throw ex
+            } catch (ex: IllegalArgumentException) {
+              if (LegacySerializer.deserialize(player, data)) return else throw ex
+            }
+    applySnapshot(player, migrateIfNeeded(snapshot))
+  }
+
+  private fun migrateIfNeeded(snapshot: PlayerSnapshot): PlayerSnapshot {
+    var current = snapshot
+    var version = snapshot.version
+    while (version < PLAYER_DATA_CURRENT_VERSION) {
+      current = migrateOnce(version, current)
+      version++
+    }
+    return current
+  }
+
+  private fun migrateOnce(fromVersion: Int, snapshot: PlayerSnapshot): PlayerSnapshot {
+    return when (fromVersion) {
+      1 -> snapshot
+      else -> snapshot
+    }
+  }
+
+  private fun applySnapshot(player: BukkitPlayer, snapshot: PlayerSnapshot) {
+    val maxHealth = player.getAttribute(Attribute.MAX_HEALTH)?.value ?: player.health
+    player.health = snapshot.health.coerceIn(0.0, maxHealth)
+    player.foodLevel = snapshot.foodLevel.coerceIn(0, 20)
+    player.exp = snapshot.xpProgress.coerceIn(0f, 1f)
+    player.inventory.heldItemSlot =
+            snapshot.selectedItemSlot.coerceIn(0, player.inventory.contents.size - 1)
+
+    player.activePotionEffects.forEach { player.removePotionEffect(it.type) }
+    snapshot.potionEffects.forEach { eff ->
+      val typeKey = NamespacedKey.fromString(eff.type)
+      val type = typeKey?.let { key -> mobEffectRegistry?.get(key) }
+      if (type == null) {
+        App.instance.logger.warning("Unknown potion effect key during restore: ${eff.type}")
+        return@forEach
+      }
+      val potion = PotionEffect(type, eff.duration, eff.amplifier, eff.ambient, eff.particles, eff.icon)
+      player.addPotionEffect(potion)
+    }
+
+    player.inventory.clear()
+    snapshot.inventory.forEachIndexed { index, item ->
+      player.inventory.setItem(index, item?.let(::deserializeItemStack))
+    }
+
+    player.enderChest.clear()
+    snapshot.enderChest.forEachIndexed { index, item ->
+      player.enderChest.setItem(index, item?.let(::deserializeItemStack))
+    }
   }
 }
 
-fun ItemStacksToBase64(item: Array<ItemStack>): String {
-  return ""
+private fun serializePotionEffect(effect: PotionEffect): PotionEffectSnapshot {
+  val typeKey = effect.type.key().toString()
+  return PotionEffectSnapshot(
+          type = typeKey,
+          amplifier = effect.amplifier,
+          duration = effect.duration,
+          ambient = effect.isAmbient,
+          particles = effect.hasParticles(),
+          icon = effect.hasIcon()
+  )
 }
 
-fun fromBase64(data: String): ByteArray {
-  return byteArrayOf()
-}
+private fun serializeItemStack(item: ItemStack): ItemStackSnapshot {
+  val bytes = item.ensureServerConversions().serializeAsBytes()
+  return ItemStackSnapshot(Base64.getEncoder().encodeToString(bytes))
+}
+
+private fun deserializeItemStack(snapshot: ItemStackSnapshot): ItemStack {
+  val data = Base64.getDecoder().decode(snapshot.payload)
+  return ItemStack.deserializeBytes(data)
+}
+
+private object LegacySerializer {
+  fun deserialize(player: BukkitPlayer, data: String): Boolean {
+    return try {
+      NBT.modify(
+              player,
+              Function { nbt ->
+                val input = NBT.parseNBT(data)
+                nbt.setFloat("Health", input.getFloat("Health"))
+                nbt.setInteger("foodLevel", input.getInteger("foodLevel"))
+                nbt.setFloat("XpP", input.getFloat("XpP"))
+                nbt.setInteger("SelectedItemSlot", input.getInteger("SelectedItemSlot"))
+                val activeEffects = nbt.getCompoundList("active_effects")
+                activeEffects.clear()
+                input.getCompoundList("active_effects").forEach { activeEffects.addCompound(it) }
+                val inventory = nbt.getCompoundList("Inventory")
+                inventory.clear()
+                input.getCompoundList("Inventory").forEach { inventory.addCompound(it) }
+                val enderchest = nbt.getCompoundList("EnderItems")
+                enderchest.clear()
+                input.getCompoundList("EnderItems").forEach { enderchest.addCompound(it) }
+              }
+      )
+      App.instance.logger.info("Legacy player data applied; will be migrated on next save.")
+      true
+    } catch (_: Exception) {
+      false
+    }
+  }
+}

src/main/kotlin/net/hareworks/simplymcdb/Players.kt

@@ -0,0 +1,95 @@
+package net.hareworks.simplymcdb
+
+import java.util.UUID
+import net.hareworks.simplymcdb.database.Database
+import org.bukkit.entity.Player as BukkitPlayer
+import org.jetbrains.exposed.sql.*
+import org.jetbrains.exposed.sql.transactions.transaction
+
+public object Players : Table() {
+  val id = integer("id").autoIncrement()
+
+  val uuid = varchar("uuid", 36)
+  val name = varchar("name", 16)
+  val firstLogin = long("first_login")
+  val playTime = long("play_time").default(0)
+  val lastOnline = long("last_online").default(0)
+  val lastIp = varchar("last_ip", 15)
+
+  val data = text("data").default("")
+  val dataVersion = integer("data_version").default(0)
+
+  override val primaryKey = PrimaryKey(uuid)
+}
+
+public fun isRegistered(player: UUID): Boolean {
+  return transaction(Database.instance) {
+    val data =
+            Players.select(Players.uuid).where { Players.uuid eq player.toString() }.map {
+              it[Players.uuid]
+            }
+    data.isNotEmpty()
+  }
+}
+
+public fun register(player: BukkitPlayer) {
+  transaction(Database.instance) {
+    Players.insert {
+      it[uuid] = player.uniqueId.toString()
+      it[name] = player.name
+      it[firstLogin] = System.currentTimeMillis()
+      it[lastOnline] = System.currentTimeMillis()
+      it[lastIp] = player.address?.address?.hostAddress ?: "unknown"
+      it[dataVersion] = 0
+    }
+  }
+}
+
+public fun update(player: BukkitPlayer) {
+  val dat = PlayerSerializer.serialize(player)
+  transaction(Database.instance) {
+    Players.update({ Players.uuid eq player.uniqueId.toString() }) {
+      it[lastOnline] = System.currentTimeMillis()
+      it[lastIp] = player.address?.address?.hostAddress ?: "unknown"
+
+      // player.sendMessage(dat)
+      it[data] = dat
+      it[dataVersion] = PLAYER_DATA_CURRENT_VERSION
+    }
+  }
+}
+
+public fun fetch(player: BukkitPlayer) {
+  val dat =
+          transaction(Database.instance) {
+            Players.select(Players.uuid, Players.data)
+                    .where { Players.uuid eq player.uniqueId.toString() }
+                    .withDistinct()
+                    .map { it[Players.data] }
+                    .first()
+          }
+  // player.sendMessage(dat)
+  PlayerSerializer.deserialize(player, dat)
+}
+
+data class PlayerDataEntry(val uuid: UUID, val serialized: String, val version: Int)
+
+public fun findPlayersNeedingMigration(): List<PlayerDataEntry> {
+  return transaction(Database.instance) {
+    Players
+            .selectAll()
+            .where { (Players.dataVersion less PLAYER_DATA_CURRENT_VERSION) and (Players.data neq "") }
+            .map {
+              PlayerDataEntry(UUID.fromString(it[Players.uuid]), it[Players.data], it[Players.dataVersion])
+            }
+  }
+}
+
+public fun overwritePlayerData(uuid: UUID, data: String, version: Int = PLAYER_DATA_CURRENT_VERSION) {
+  transaction(Database.instance) {
+    Players.update({ Players.uuid eq uuid.toString() }) {
+      it[Players.data] = data
+      it[Players.dataVersion] = version
+    }
+  }
+}

src/main/kotlin/net/hareworks/simplymcdb/database/Database.kt

@@ -1,8 +1,8 @@
 package net.hareworks.simplymcdb.database
 
 import net.hareworks.simplymcdb.App
-import net.hareworks.simplymcdb.config.config
-import net.hareworks.simplymcdb.playerdata.Player
+import net.hareworks.simplymcdb.Config
+import net.hareworks.simplymcdb.Players
 import org.jetbrains.exposed.sql.*
 import org.jetbrains.exposed.sql.Database
 import org.jetbrains.exposed.sql.transactions.transaction
@@ -10,7 +10,9 @@ import org.jetbrains.exposed.sql.transactions.transaction
 public object Database {
   public var instance: Database? = null
     private set
+
   public fun connect() {
+    var config = Config.config
     val type = config.getString("database.type")
     val host = config.getString("database.host")
     val port = config.getInt("database.port")
@@ -49,11 +51,7 @@ public object Database {
     }
     if (instance == null) return
     App.instance.logger.info("Database connected: $host:$port/$database")
-    if (!ping()) {
-      App.instance.logger.warning("Database ping failed")
-    } else {
-      App.instance.logger.info("Database ping successful")
-    }
+    transaction(instance) { SchemaUtils.createMissingTablesAndColumns(Players) }
   }
   public fun disconnect() {
     instance?.let {
@@ -66,20 +64,23 @@ public object Database {
   }
 
   public fun ping(): Boolean {
+    val flag = (instance == null)
+    if (flag) connect()
     return try {
-      transaction {
-        addLogger(StdOutSqlLogger)
-        exec("SELECT 1")
-      }
+      transaction(instance) { exec("SELECT 1") }
       true
     } catch (e: Exception) {
       false
+    } finally {
+      if (flag) disconnect()
     }
   }
 
   public fun initialize() {
-    transaction {
-      SchemaUtils.create(Player)
-    }
+    transaction(instance) { SchemaUtils.create(Players) }
+  }
+
+  public fun reset() {
+    transaction(instance) { SchemaUtils.drop(Players) }
   }
 }

src/main/resources/config.yml

@@ -1,18 +1,24 @@
-enable: false
 database:
-  type: postgresql
+  type: postgresql  # Supported: mysql, postgresql
   host: localhost
   port: 5432
+  # You must have created a database and user.
   database: smcdb
   user: smcdb
-  password: SaN1m_wk2eh9
-playerdata:
+  password: password
+
+playerdata: # README for more details.
   health: true
   hunger: true
   experience: true
-  status: true
+  effects: true
   inventory: true
   enderchest: true
   # achievements: true
   # recipebook: true
-  gamemode: true
+  gamemode: true
+  
+
+# Do not change this value manually,
+# If the plugin settings are OK, enable it with the command.
+enabled: false