kiafumi/src/main/java/moe/oko/Kiafumi/model/KiafumiDB.java

package moe.oko.Kiafumi.model;

import com.mysql.cj.xdevapi.Type;
import net.dv8tion.jda.api.entities.Guild;

import java.sql.*;

import static moe.oko.Kiafumi.Kiafumi.error;
import static moe.oko.Kiafumi.Kiafumi.info;

/**
 * Kiafumi DB Class
 * Basically our helpful MySQL functions that pertain to data persistence.
 */
public class KiafumiDB {
    //Our actual MySQL Connection, this is created on class construction.
    private Connection connection;

    //The prepared statement strings
    private final String CREATE_SERVERINFO_TABLE = "CREATE TABLE IF NOT EXISTS `serverInfo`" +
            "(`id` LONGTEXT NOT NULL,`welcomeEnabled` TINYINT NOT NULL,`welcomeChannel` LONGTEXT NULL);";
    private final String INSERT_SERVERINFO_DEFAULT = "INSERT INTO serverInfo(id,welcomeEnabled,welcomeChannel) values (?,?,?)";
    private final String SERVERINFO_EXISTS = "select * from serverInfo where id = ?";

    /**
     * KiafumiDB Config Constructor
     * @param username - username to access database
     * @param password - password to access database
     * @param host - host for server
     * @param port - port for server (3306 is default)
     * @param db - database name
     */
    public KiafumiDB(String username, String password, String host, int port, String db) {
        try {
            connection = DriverManager.getConnection("jdbc:mysql://" + host + ":" + port + "/" + db, username, password);
        } catch (Exception ex) {
            error("Failed to initialize the MySQL instance. Contact a developer.");
            ex.printStackTrace();
            return;
        }

        initializeTables();
    }

    /**
     * Table initialization function, ran on every startup.
     */
    private void initializeTables() {
        try {
            connection.prepareStatement(CREATE_SERVERINFO_TABLE).execute();
        } catch (Exception ex) {
            ex.printStackTrace();
            error("Failed to initialize SQL tables. They may need to be created manually.");
        }
    }

    /**
     * Creates the default server information when the bot joins a discord.
     * @param guild - the guild that the bot joined
     * @return whether the function succeeded.
     */
    public boolean createServerInformation(Guild guild) {
        try {
            PreparedStatement prep = connection.prepareStatement(SERVERINFO_EXISTS);
            prep.setInt(1, (int) guild.getIdLong());
            ResultSet rsCheck = prep.executeQuery();
            while (rsCheck.next()) {
                //Server already exists, no need to initialize a section for it.
                if(rsCheck.getInt(1) != 0) {
                    info("Server already existed. Skipping initialization.");
                    return true;
                }
            }
            //Proceed with making defaults.
            PreparedStatement ps = connection.prepareStatement(INSERT_SERVERINFO_DEFAULT);
            ps.setString(1, guild.getId());
            ps.setInt(2, 0); //default is false.
            ps.setNull(3, Types.LONGVARCHAR);
            ps.execute();
            return true;
        } catch (Exception ex) {
            error("Failed to create default server info for guild " + guild.getId());
            ex.printStackTrace();
            return false;
        }
    }
}