⚡ Optimize SQLManager.getMainMedal with JOIN query

modules/MedalCabinet/pom.xml

@@ -81,5 +81,23 @@
             <version>2.11.1</version>
             <scope>provided</scope>
         </dependency>
+        <dependency>
+            <groupId>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter</artifactId>
+            <version>5.9.2</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.mockito</groupId>
+            <artifactId>mockito-core</artifactId>
+            <version>4.11.0</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.mockito</groupId>
+            <artifactId>mockito-junit-jupiter</artifactId>
+            <version>4.11.0</version>
+            <scope>test</scope>
+        </dependency>
     </dependencies>
 </project>

modules/MedalCabinet/src/main/java/com/mcatk/medalcabinet/sql/SQLManager.java

@@ -15,6 +15,14 @@ public static SQLManager getInstance() {
         return instance == null ? instance = new SQLManager() : instance;
     }
 
+    public static void setInstance(SQLManager newInstance) {
+        instance = newInstance;
+    }
+
+    protected SQLManager(Connection connection) {
+        this.connection = connection;
+    }
+
     private SQLManager() {
         connectMySQL();
     }
@@ -168,12 +176,17 @@ public boolean setMainMedal(String playerID, String medalID) {
     public Medal getMainMedal(String playerID) {
         Medal medal = null;
         try (PreparedStatement ps = connection.prepareStatement(
-                "SELECT medal_id FROM `player_main_medal` WHERE player_id = ?"
+                "SELECT m.* FROM medal m INNER JOIN player_main_medal pmm ON m.medal_id = pmm.medal_id WHERE pmm.player_id = ?"
         )) {
             ps.setString(1, playerID);
             ResultSet rs = ps.executeQuery();
             if (rs.next()) {
-                medal = getMedal(rs.getString("medal_id"));
+                medal = new Medal(
+                        rs.getString("medal_id"),
+                        rs.getString("medal_name"),
+                        rs.getString("medal_material"),
+                        rs.getString("medal_description")
+                );
             }
         } catch (SQLException e) {
             e.printStackTrace();

modules/MedalCabinet/src/test/java/com/mcatk/medalcabinet/sql/SQLManagerTest.java

@@ -0,0 +1,79 @@
+package com.mcatk.medalcabinet.sql;
+
+import com.mcatk.medalcabinet.medal.Medal;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.Mock;
+import org.mockito.junit.jupiter.MockitoExtension;
+
+import java.sql.Connection;
+import java.sql.PreparedStatement;
+import java.sql.ResultSet;
+import java.sql.SQLException;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.mockito.ArgumentMatchers.anyString;
+import static org.mockito.Mockito.*;
+
+@ExtendWith(MockitoExtension.class)
+public class SQLManagerTest {
+
+    @Mock
+    private Connection connection;
+
+    @Mock
+    private PreparedStatement preparedStatement1;
+    @Mock
+    private PreparedStatement preparedStatement2;
+
+    @Mock
+    private ResultSet resultSet1;
+    @Mock
+    private ResultSet resultSet2;
+
+    private SQLManager sqlManager;
+
+    @BeforeEach
+    public void setUp() {
+        // Use the protected constructor to inject the mock connection
+        // We can do this because the test class is in the same package
+        sqlManager = new SQLManager(connection);
+        // Set the singleton instance
+        SQLManager.setInstance(sqlManager);
+    }
+
+    @Test
+    public void testGetMainMedal_Optimized() throws SQLException {
+        // Arrange
+        String playerId = "testPlayer";
+        String medalId = "medal123";
+        String medalName = "Gold Medal";
+        String medalMat = "GOLD_INGOT";
+        String medalDesc = "A shiny gold medal";
+
+        // Mock the JOIN query: SELECT m.* FROM medal m INNER JOIN player_main_medal pmm ...
+        when(connection.prepareStatement(contains("INNER JOIN"))).thenReturn(preparedStatement1);
+        when(preparedStatement1.executeQuery()).thenReturn(resultSet1);
+        when(resultSet1.next()).thenReturn(true);
+        when(resultSet1.getString("medal_id")).thenReturn(medalId);
+        when(resultSet1.getString("medal_name")).thenReturn(medalName);
+        when(resultSet1.getString("medal_material")).thenReturn(medalMat);
+        when(resultSet1.getString("medal_description")).thenReturn(medalDesc);
+
+        // Act
+        Medal result = sqlManager.getMainMedal(playerId);
+
+        // Assert
+        assertNotNull(result);
+        assertEquals(medalId, result.getId());
+        assertEquals(medalName, result.getName());
+
+        // Verify that prepareStatement was called only once (optimized behavior)
+        verify(connection, times(1)).prepareStatement(anyString());
+
+        // Specific verification
+        verify(connection).prepareStatement(contains("INNER JOIN"));
+    }
+}