Added replay saving/loading and score database auto-updater.

- Added 'info' table to score database to store the database version.  Upon startup, if the stored version is less than the source version, all update queries defined in ScoreDB.getUpdateQueries() will be run.
- Created "Replays" directory to store replay files.  Replay files are created after gameplay.
- Added 'replay' column to the score database to hold replay file names.
- Created a Game.loadOsuFile() method to load game data.

Signed-off-by: Jeffrey Han <itdelatrisu@gmail.com>

src/itdelatrisu/opsu/db/ScoreDB.java

@@ -32,6 +32,7 @@ import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.HashMap;
+import java.util.LinkedList;
 import java.util.List;
 import java.util.Map;
 
@@ -39,6 +40,29 @@ import java.util.Map;
  * Handles connections and queries with the scores database.
  */
 public class ScoreDB {
+	/**
+	 * Current database version.
+	 * This value should be changed whenever the database format changes.
+	 * Add any update queries to the {@link #getUpdateQueries(int)} method.
+	 */
+	private static final int DATABASE_VERSION = 20140311;
+
+	/**
+	 * Returns a list of SQL queries to apply, in order, to update from
+	 * the given database version to the latest version.
+	 * @param version the current version
+	 * @return a list of SQL queries
+	 */
+	private static List<String> getUpdateQueries(int version) {
+		List<String> list = new LinkedList<String>();
+		if (version < 20140311)
+			list.add("ALTER TABLE scores ADD COLUMN replay TEXT");
+
+		/* add future updates here */
+
+		return list;
+	}
+
 	/** Database connection. */
 	private static Connection connection;
 
@@ -63,13 +87,16 @@ public class ScoreDB {
 		if (connection == null)
 			return;
 
+		// run any database updates
+		updateDatabase();
+
 		// create the database
 		createDatabase();
 
 		// prepare sql statements
 		try {
 			insertStmt = connection.prepareStatement(
-				"INSERT INTO scores VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)"
+				"INSERT INTO scores VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)"
 			);
 			selectMapStmt = connection.prepareStatement(
 				"SELECT * FROM scores WHERE " +
@@ -109,15 +136,75 @@ public class ScoreDB {
 					"score INTEGER, " +
 					"combo INTEGER, " +
 					"perfect BOOLEAN, " +
-					"mods INTEGER" +
+					"mods INTEGER, " +
+					"replay TEXT" +
 				");" +
+				"CREATE TABLE IF NOT EXISTS info (" +
+					"key TEXT NOT NULL UNIQUE, value TEXT" +
+				"); " +
 				"CREATE INDEX IF NOT EXISTS idx ON scores (MID, MSID, title, artist, creator, version);";
 			stmt.executeUpdate(sql);
+
+			// set the version key, if empty
+			sql = String.format("INSERT OR IGNORE INTO info(key, value) VALUES('version', %d)", DATABASE_VERSION);
+			stmt.executeUpdate(sql);
 		} catch (SQLException e) {
 			ErrorHandler.error("Could not create score database.", e, true);
 		}
 	}
 
+	/**
+	 * Applies any database updates by comparing the current version to the
+	 * stored version.  Does nothing if tables have not been created.
+	 */
+	private static void updateDatabase() {
+		try (Statement stmt = connection.createStatement()) {
+			int version = 0;
+
+			// if 'info' table does not exist, assume version 0 and apply all updates
+			String sql = "SELECT name FROM sqlite_master WHERE type = 'table' AND name = 'info'";
+			ResultSet rs = stmt.executeQuery(sql);
+			boolean infoExists = rs.isBeforeFirst();
+			rs.close();
+			if (!infoExists) {
+				// if 'scores' table also does not exist, databases not yet created
+				sql = "SELECT name FROM sqlite_master WHERE type = 'table' AND name = 'scores'";
+				ResultSet scoresRS = stmt.executeQuery(sql);
+				boolean scoresExists = scoresRS.isBeforeFirst();
+				scoresRS.close();
+				if (!scoresExists)
+					return;
+			} else {
+				// try to retrieve stored version
+				sql = "SELECT value FROM info WHERE key = 'version'";
+				ResultSet versionRS = stmt.executeQuery(sql);
+				String versionString = (versionRS.next()) ? versionRS.getString(1) : "0";
+				versionRS.close();
+				try {
+					version = Integer.parseInt(versionString);
+				} catch (NumberFormatException e) {}
+			}
+
+			// database versions match
+			if (version >= DATABASE_VERSION)
+				return;
+
+			// apply updates
+			for (String query : getUpdateQueries(version))
+				stmt.executeUpdate(query);
+
+			// update version
+			if (infoExists) {
+				PreparedStatement ps = connection.prepareStatement("REPLACE INTO info (key, value) VALUES ('version', ?)");
+				ps.setString(1, Integer.toString(DATABASE_VERSION));
+				ps.executeUpdate();
+				ps.close();
+			}
+		} catch (SQLException e) {
+			ErrorHandler.error("Failed to update score database.", e, true);
+		}
+	}
+
 	/**
 	 * Adds the game score to the database.
 	 * @param data the GameData object
@@ -128,6 +215,7 @@ public class ScoreDB {
 
 		try {
 			setStatementFields(insertStmt, data);
+			insertStmt.setString(18, data.replayString);
 			insertStmt.executeUpdate();
 		} catch (SQLException e) {
 			ErrorHandler.error("Failed to save score to database.", e, true);