import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;


public class GasStation {
    //Constants to provide information that should probably be pulled from a DB
    private static final float LEADED_FEDERAL_TAX = 0.10F;
    private static final float UNLEADED_FEDERAL_TAX = 0.15F;
    private static final float STATE_TAX = 0.05F;
    private static final float LEADED_GALLON_COST = 3.0F;
    private static final float UNLEADED_GALLON_COST = 3.5F;
    private static final float FULL_SERVICE_CHARGE = 2.0F;
    private static final float GASNGO_SERVICE_CHARGE = 2.0F;

    //Variable to hold the command line arguments so they're easier to read
    private static String gasType = "Leaded";
    private static float gallons = 10;
    private static String serviceType = "FullService";

    private static float federalTax;
    private static float gallonCost;
    private static float serviceCharge;
    private static float gasCharge;
    private static float totalBill;

    public static void main(String[] args) {
        //Create a connection object
        Connection con = null;

        //Error handling try/catch
        try {
            //get the jdbc driver
          Class.forName("com.mysql.jdbc.Driver").newInstance();
          //try to connect to my db
          con = DriverManager.getConnection("jdbc:mysql:///gascharges", "root", "14142135");

          //if the connection succeeded
          if(!con.isClosed()) {
            System.out.println("Successfully connected to MySQL server...");
            //Make a statement object to hold our sql statement
            Statement stmt = con.createStatement();
            //Make a result set to hold the result of our sql statement
            ResultSet rs = stmt.executeQuery("SELECT * FROM pumprecords;");
            //Move to the first record
            rs.next();

            while (!rs.isLast()) {
                //Set the main variables using the passed command line args.  Should catch invalid args
                //  but wanted to keep it simple.
                gasType = rs.getString("gasType");
                gallons = Float.valueOf(rs.getString("gallons")); //An argument is a string and must be forced to convert to a float
                serviceType = rs.getString("serviceType");

                //Strings are objects unlike other data types.  Must use myString.equals("other string").  Can't
                //  use myString = "other string" since myString is a reference to a memory address,
                //  not an actual string.
                if (gasType.equals("Leaded")) {
                    federalTax = LEADED_FEDERAL_TAX;
                    gallonCost = LEADED_GALLON_COST;
                } else {
                    federalTax = UNLEADED_FEDERAL_TAX;
                    gallonCost = UNLEADED_GALLON_COST;
                }

                //Both these ifs should really uppercase both strings so the command line arguments
                //  aren't case sensitive
                if (serviceType.equals("FullService")) {
                    serviceCharge = FULL_SERVICE_CHARGE;
                } else if (serviceType.equals("GasNGo")) {
                    serviceCharge = GASNGO_SERVICE_CHARGE;
                } else {
                    serviceCharge = 0F;
                }

                gasCharge = gallonCost * gallons;

                totalBill = ((gasCharge + serviceCharge) * (1.0f + STATE_TAX)) + (federalTax * gallons);

                //This println should format totalBill to force $0.00 format.  Again, keeping it simple.
                System.out.println("Total Charge: $" + Float.toString(totalBill));
                rs.next();
            }
          }

        } catch(Exception e) {
          System.err.println("Exception: " + e.getMessage());
        } finally {
          try {
            if(con != null)
              con.close();
          } catch(SQLException e) {}
        }
    }
}