Add optional MySQL support for statistics storage

src/main/java/us/tss3/blockparty/BlockPartyPlugin.java

@@ -42,7 +42,7 @@ public class BlockPartyPlugin extends JavaPlugin implements Listener {
         this.sessionManager = new SessionManager();
         this.soundUtil = new SoundUtil(this);
         this.rewardManager = new RewardManager(this);
-        this.statsManager = new StatsManager(this);
+        this.statsManager = new StatsManager(this, configManager.getStorageSettings());
         statsManager.init();
 
         this.arenaManager = new ArenaManager(this);

src/main/java/us/tss3/blockparty/config/ConfigManager.java

@@ -80,4 +80,27 @@ public class ConfigManager {
     public boolean isPlaceholderApiEnabled() {
         return config.getBoolean("integrations.placeholderapi", true);
     }
+
+    public StorageSettings getStorageSettings() {
+        String type = config.getString("storage.type", "sqlite");
+        return new StorageSettings(
+                type,
+                config.getString("storage.mysql.host", "localhost"),
+                config.getInt("storage.mysql.port", 3306),
+                config.getString("storage.mysql.database", "blockparty"),
+                config.getString("storage.mysql.username", "blockparty"),
+                config.getString("storage.mysql.password", ""),
+                config.getBoolean("storage.mysql.use-ssl", false),
+                config.getString("storage.mysql.table-prefix", "bp_")
+        );
+    }
+
+    /** Immutable snapshot of the storage.* config section. */
+    public record StorageSettings(String type, String host, int port, String database,
+                                   String username, String password, boolean useSsl, String tablePrefix) {
+
+        public boolean isMysql() {
+            return "mysql".equalsIgnoreCase(type);
+        }
+    }
 }

src/main/java/us/tss3/blockparty/persistence/StatsDatabase.java

@@ -1,6 +1,7 @@
 package us.tss3.blockparty.persistence;
 
 import org.bukkit.plugin.Plugin;
+import us.tss3.blockparty.config.ConfigManager.StorageSettings;
 
 import java.io.File;
 import java.sql.Connection;
@@ -12,37 +13,72 @@ import java.sql.Statement;
 import java.util.UUID;
 import java.util.logging.Level;
 
-/** SQLite-backed statistics storage. All public methods are safe to call from any thread;
- *  callers are expected to invoke them off the main thread (see StatsManager). */
+/** SQLite- or MySQL-backed statistics storage, selected via storage.type in config.yml.
+ *  All public methods are safe to call from any thread; callers are expected to invoke
+ *  them off the main thread (see StatsManager). */
 public class StatsDatabase {
 
     private final Plugin plugin;
+    private final StorageSettings settings;
+    private final String table;
     private Connection connection;
 
-    public StatsDatabase(Plugin plugin) {
+    public StatsDatabase(Plugin plugin, StorageSettings settings) {
         this.plugin = plugin;
+        this.settings = settings;
+        this.table = settings.isMysql() ? settings.tablePrefix() + "player_stats" : "player_stats";
     }
 
     public synchronized void connect() {
         try {
-            File dbFile = new File(plugin.getDataFolder(), "blockparty.db");
-            Class.forName("org.sqlite.JDBC");
-            connection = DriverManager.getConnection("jdbc:sqlite:" + dbFile.getAbsolutePath());
+            if (settings.isMysql()) {
+                connectMysql();
+            } else {
+                connectSqlite();
+            }
             try (Statement st = connection.createStatement()) {
-                st.execute("CREATE TABLE IF NOT EXISTS player_stats (" +
-                        "uuid TEXT PRIMARY KEY," +
-                        "games_played INTEGER NOT NULL DEFAULT 0," +
-                        "wins INTEGER NOT NULL DEFAULT 0," +
-                        "eliminations INTEGER NOT NULL DEFAULT 0," +
-                        "best_round INTEGER NOT NULL DEFAULT 0," +
-                        "total_rounds_survived INTEGER NOT NULL DEFAULT 0" +
-                        ")");
+                st.execute(createTableStatement());
             }
         } catch (Exception ex) {
-            plugin.getLogger().log(Level.SEVERE, "Failed to initialize SQLite stats database", ex);
+            plugin.getLogger().log(Level.SEVERE, "Failed to initialize " +
+                    (settings.isMysql() ? "MySQL" : "SQLite") + " stats database", ex);
         }
     }
 
+    private void connectSqlite() throws Exception {
+        File dbFile = new File(plugin.getDataFolder(), "blockparty.db");
+        Class.forName("org.sqlite.JDBC");
+        connection = DriverManager.getConnection("jdbc:sqlite:" + dbFile.getAbsolutePath());
+    }
+
+    private void connectMysql() throws Exception {
+        Class.forName("com.mysql.cj.jdbc.Driver");
+        String url = "jdbc:mysql://" + settings.host() + ":" + settings.port() + "/" + settings.database()
+                + "?useSSL=" + settings.useSsl() + "&autoReconnect=true&characterEncoding=utf8";
+        connection = DriverManager.getConnection(url, settings.username(), settings.password());
+    }
+
+    private String createTableStatement() {
+        if (settings.isMysql()) {
+            return "CREATE TABLE IF NOT EXISTS " + table + " (" +
+                    "uuid VARCHAR(36) PRIMARY KEY," +
+                    "games_played INT NOT NULL DEFAULT 0," +
+                    "wins INT NOT NULL DEFAULT 0," +
+                    "eliminations INT NOT NULL DEFAULT 0," +
+                    "best_round INT NOT NULL DEFAULT 0," +
+                    "total_rounds_survived INT NOT NULL DEFAULT 0" +
+                    ")";
+        }
+        return "CREATE TABLE IF NOT EXISTS " + table + " (" +
+                "uuid TEXT PRIMARY KEY," +
+                "games_played INTEGER NOT NULL DEFAULT 0," +
+                "wins INTEGER NOT NULL DEFAULT 0," +
+                "eliminations INTEGER NOT NULL DEFAULT 0," +
+                "best_round INTEGER NOT NULL DEFAULT 0," +
+                "total_rounds_survived INTEGER NOT NULL DEFAULT 0" +
+                ")";
+    }
+
     public synchronized void close() {
         try {
             if (connection != null && !connection.isClosed()) {
@@ -53,8 +89,10 @@ public class StatsDatabase {
     }
 
     private synchronized void ensureRow(String uuid) throws SQLException {
-        try (PreparedStatement ps = connection.prepareStatement(
-                "INSERT OR IGNORE INTO player_stats(uuid) VALUES (?)")) {
+        String sql = settings.isMysql()
+                ? "INSERT IGNORE INTO " + table + "(uuid) VALUES (?)"
+                : "INSERT OR IGNORE INTO " + table + "(uuid) VALUES (?)";
+        try (PreparedStatement ps = connection.prepareStatement(sql)) {
             ps.setString(1, uuid);
             ps.executeUpdate();
         }
@@ -67,7 +105,7 @@ public class StatsDatabase {
         try {
             ensureRow(uuid.toString());
             try (PreparedStatement ps = connection.prepareStatement(
-                    "SELECT games_played, wins, eliminations, best_round, total_rounds_survived FROM player_stats WHERE uuid=?")) {
+                    "SELECT games_played, wins, eliminations, best_round, total_rounds_survived FROM " + table + " WHERE uuid=?")) {
                 ps.setString(1, uuid.toString());
                 try (ResultSet rs = ps.executeQuery()) {
                     if (rs.next()) {
@@ -100,7 +138,7 @@ public class StatsDatabase {
         try {
             ensureRow(uuid.toString());
             try (PreparedStatement ps = connection.prepareStatement(
-                    "UPDATE player_stats SET best_round = MAX(best_round, ?), total_rounds_survived = total_rounds_survived + 1 WHERE uuid=?")) {
+                    "UPDATE " + table + " SET best_round = MAX(best_round, ?), total_rounds_survived = total_rounds_survived + 1 WHERE uuid=?")) {
                 ps.setInt(1, round);
                 ps.setString(2, uuid.toString());
                 ps.executeUpdate();
@@ -117,7 +155,7 @@ public class StatsDatabase {
         try {
             ensureRow(uuid.toString());
             try (PreparedStatement ps = connection.prepareStatement(
-                    "UPDATE player_stats SET " + setClause + " WHERE uuid=?")) {
+                    "UPDATE " + table + " SET " + setClause + " WHERE uuid=?")) {
                 ps.setString(1, uuid.toString());
                 ps.executeUpdate();
             }

src/main/java/us/tss3/blockparty/persistence/StatsManager.java

@@ -1,6 +1,7 @@
 package us.tss3.blockparty.persistence;
 
 import org.bukkit.plugin.Plugin;
+import us.tss3.blockparty.config.ConfigManager.StorageSettings;
 
 import java.util.UUID;
 import java.util.concurrent.CompletableFuture;
@@ -11,9 +12,9 @@ public class StatsManager {
     private final Plugin plugin;
     private final StatsDatabase database;
 
-    public StatsManager(Plugin plugin) {
+    public StatsManager(Plugin plugin, StorageSettings settings) {
         this.plugin = plugin;
-        this.database = new StatsDatabase(plugin);
+        this.database = new StatsDatabase(plugin, settings);
     }
 
     public void init() {