import com.h2.BestLoanRates;

import com.h2.MortgageCalculator;

import com.h2.SavingsCalculator;

import java.util.Arrays;

import java.util.Map;

public class Finance {

public static final String BEST_LOAN_RATES = "bestLoanRates";

public static final String SAVINGS_CALCULATOR = "savingsCalculator";

public static final String MORTGAGE_CALCULATOR = "mortgageCalculator";

public static final Map<String, String> commandsToUsage = Map.of(

BEST_LOAN_RATES, "usage: bestLoanRates",

SAVINGS_CALCULATOR, "usage: savingsCalculator <credits separated by ','> <debits separated by ','>",

MORTGAGE_CALCULATOR, "usage: mortgageCalculator <loanAmount> <termInYears> <annualRate>"

);

public static void main(String[] args) {

final String command = args[0];

if (!commandsToUsage.containsKey(command)) {

System.out.println(command + ": command not found");

System.exit(-1);

}

final boolean isValidCommand = validateCommandArguments(args);

if (!isValidCommand) {

System.out.println(commandsToUsage.get(args[0]));

System.exit(-1);

}

executeCommand(command, Arrays.copyOfRange(args, 1, args.length));

}

private static void executeCommand(String command, String[] arguments) {

switch (command) {

case BEST_LOAN_RATES:

System.out.println("Finding best loan rates ..."); // for testing just log

BestLoanRates.main(arguments); // for another test call these methods and have executeCommand add to main method

return;

case SAVINGS_CALCULATOR:

System.out.println("Finding your net savings ...");

SavingsCalculator.main(arguments);

return;

case MORTGAGE_CALCULATOR:

System.out.println("Finding your monthly payment ...");

MortgageCalculator.main(arguments);

}

}

private static boolean validateCommandArguments(String[] args) {

switch (args[0]) {

case BEST_LOAN_RATES:

return args.length == 1;

case SAVINGS_CALCULATOR:

return args.length == 3;

case MORTGAGE_CALCULATOR:

return args.length == 4;

}

return false;

}

}