import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.Date;

public class MySQLAccess {

	private Connection connect = null;
	private Statement statement = null;
	private ResultSet resultSet = null;

	public void connectDB() {

		try {

			Class.forName("com.mysql.jdbc.Driver");

			connect = DriverManager
					.getConnection("jdbc:mysql://localhost/merx?"
							+ "user=root&password=admin");

			statement = connect.createStatement();

		} catch (Exception e) {

			System.out.println("Failed to connect to MySQL DB");
			e.printStackTrace();
		}


	}

	public void readDataBase() {

		try {

			connectDB();

			resultSet = statement
					.executeQuery("select * from merx.inventory;");

			writeResultSet(resultSet);

		} catch (Exception e) {

			e.printStackTrace();

		} finally {

			close();
		}
	}

	public int newTransaction(Date date) {

		int id = -1;

		try {

			int refNum = getNewReferenceId() + 1;
			System.out.println("refNum = " + refNum);

			connectDB();
			String[] values = { "FALSE", "SMS", "SMS", "SMS" + refNum, "", "DELIVERY_OUT", "" };
			String query = String.format("INSERT INTO merx.warehouse_transaction " +
										 "(approval_status, date_created, date_updated, delivered_by, received_by, reference_number, remarks, transaction_type, truck) " +
										 "values (\"%s\", now(), now(), \"%s\",\"%s\",\"%s\",\"%s\",\"%s\",\"%s\");",
										 values[0], values[1], values[2], values[3], values[4], values[5], values[6]);
			System.out.println(query);
			statement.executeUpdate(query);

			resultSet = statement.executeQuery("SELECT LAST_INSERT_ID();");
			if (resultSet.next())
				id = resultSet.getInt(1);
			System.out.println("transId = " + id);

		} catch (Exception e) {
			e.printStackTrace();
		}

		close();
		return id;

	}

	public void addItemToOrder(int transId, int invId, int qty) {
		try {
			connectDB();
			String query = String.format("INSERT INTO merx.warehouse_transaction_inventory " +
										"(quantity, inventory_id, warehouse_transaction_id) " +
										"values (%d, %d, %d);",
										qty, invId, transId);
			statement.executeUpdate(query);
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			close();
		}
	}

	public int getInventoryId(String code) {

		int id = -1;
		try {
			connectDB();
			String query = String.format("SELECT id FROM merx.inventory WHERE code = \"%s\";", code);
			resultSet = statement.executeQuery(query);
			if (resultSet.next())
				id = resultSet.getInt(1);
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			close();
		}
		return id;
	}

	private int getNewReferenceId(){
		int id = -1;
		try{
			connectDB();
			resultSet = statement.executeQuery("SELECT MAX(id) FROM warehouse_transaction;");
			if (resultSet.next())
				id = resultSet.getInt(1);
		}
		catch(Exception e){
			e.printStackTrace();
		} finally {
			close();
		}
		return id;
	}

	private void writeResultSet(ResultSet resultSet) throws SQLException {
		ResultSetMetaData resMeta = resultSet.getMetaData();
		int colCount = resMeta.getColumnCount();

		while (resultSet.next()) {
			for (int i = 1; i <= colCount - 1; i++) {
				System.out.print(resultSet.getObject(i).toString() + "|");
			}
			System.out.println(resultSet.getObject(colCount).toString());
		}
	}

	private void close() {

		try {
			if (resultSet != null) {
				resultSet.close();
			}

			if (statement != null) {
				statement.close();
			}

			if (connect != null) {
				connect.close();
			}
		} catch (Exception e) {

		}
	}

}