package me.ollie_2411.t2.mysql;

import java.sql.*;

/**
 * Created by Ollie on 04/01/2017.
 */
public class MySQL {

    private String host, database, username, password;
    private int port;
    private Connection connection;

    public MySQL(String host, int port, String database, String username, String password) {
        this.host = host; // retrieves the details of the database from when the class is initialised in the Game class
        this.port = port;
        this.database = database;
        this.username = username;
        this.password = password;
    }

    public void openConnection() { // opens the connection with the databse
        try {
            Class.forName("com.mysql.jdbc.Driver"); // the jdbc driver class must be loaded in order to use the MySQL connection
        } catch (ClassNotFoundException e) { // throws the error if the jdbc driver class is not present
            e.printStackTrace(); // prints the error log to the console
            return; // returns out of the method as the jdbc drivers have not be installed
        }

        try {
            if (connection != null) { // if there already is an open connection
                closeConnection(); // close the connection as multiple connections could cause problems
            }
            connection = DriverManager.getConnection("jdbc:mysql://" + host + ":" + port + "/" + database, username, password); // connects to the database
        } catch (SQLException e) { // the above code could throw a SQL exception
            e.printStackTrace(); // prints the SQL error to console
        }
    }

    public void closeConnection() { // closes the connection with the database
        try {
            if (connection != null) { // if there already is an open connection
                connection.close(); // close the connection as multiple connections could cause problems
            }
        } catch (SQLException e) { // the above code could throw a SQL exception
            e.printStackTrace(); // prints the SQL error to console
        }
    }

    public Statement createStatement(String query) {
        Statement statement = null; // used for executing a SQL query
        try {
            if (connection != null) { // if there already is an open connection
                statement = connection.createStatement(); // creates a statement object for sending SQL queries to the database
                statement.executeQuery(query); // executes the given SQL statement
            }
        } catch (SQLException e) { // the above code could throw a SQL exception
            e.printStackTrace(); // prints the SQL error to console
        }
        return statement; // returns the statement
    }

    public PreparedStatement preparedStatement(String query) {
        PreparedStatement statement = null; // an object that represents a precompiled SQL statement
        try {
            if (connection != null) { // if there already is an open connection
                statement = connection.prepareStatement(query); // generates a ResultSet object with the given type
            }
        } catch (SQLException e) { // the above code could throw a SQL exception
            e.printStackTrace(); // prints the SQL error to console
        }
        return statement; // returns the statement
    }

    public void executeUpdate(PreparedStatement statement) { // used if no result is returned when executing the query
        try {
            statement.executeUpdate(); // executes the given SQL statement which doesn't return any results
        } catch (SQLException e) { // could throw a SQL exception
            e.printStackTrace(); // print the SQL error to console
        } finally { // the code within the finally block will run not matter whether an exception is thrown or not
            try {
                if (!statement.isClosed()) { // checks if the SQL query is still running
                    statement.close(); // closes the SQL query
                }
            } catch (SQLException e) { // could throw a SQL exception
                e.printStackTrace(); // prints the SQL error to console
            }
        }
    }
}