SimulSolverHandler.java

import Scientific.SimulSolver;
import java.util.*;

public class SimulSolverHandler {

    private final Scanner scanner;

    public SimulSolverHandler(Scanner scanner) {
        this.scanner = scanner;
    }

    public void startSimulSolver() {
        boolean retry = true;
        while (retry) {
            clearScreen();
            printBanner();
            try {
                System.out.println("1. 2x2 System of Equations");
                System.out.println("2. 3x3 System of Equations");
                System.out.println("3. Return to Main Menu");

                System.out.print("Choose an option (1-3): ");
                int choice = Integer.parseInt(scanner.nextLine().trim());

                switch (choice) {
                    case 1:
                        solve2x2System();
                        break;
                    case 2:
                        solve3x3System();
                        break;
                    case 3:
                        System.out.println("Returning to Main Menu...");
                        retry = false;
                        break;
                    default:
                        System.out.println("Invalid option. Please choose 1-3.");
                        pauseScreen();
                }
            } catch (Exception e) {
                System.err.println("Invalid input. Please try again.");
                pauseScreen();
            }
        }
    }

    private void solve2x2System() {
        clearScreen();
        System.out.println("\n\033[1;34mEnter two equations in the form: ax + by = c\033[0m\n");

        double[][] A = new double[2][2];
        double[][] B = new double[2][1];

        for (int i = 0; i < 2; i++) {
            System.out.printf("Enter equation %d: ", i + 1);
            String equation = scanner.nextLine().trim();

            Map<String, Double> coefficients = parseEquation(equation, new String[]{"x", "y"});
            A[i][0] = coefficients.getOrDefault("x", 0.0);
            A[i][1] = coefficients.getOrDefault("y", 0.0);
            B[i][0] = coefficients.get("constant");
        }

        try {
            double[] solution = SimulSolver.solve2x2(A, B);
            System.out.printf("Solution:\n x = %.6f, y = %.6f\n", solution[0], solution[1]);
        } catch (Exception e) {
            System.out.println("Error: " + e.getMessage());
        }
        pauseScreen();
    }

    private void solve3x3System() {
        clearScreen();
        System.out.println("\n\033[1;34mEnter three equations in the form: ax + by + cz = d\033[0m\n");

        double[][] A = new double[3][3];
        double[][] B = new double[3][1];

        for (int i = 0; i < 3; i++) {
            System.out.printf("Enter equation %d: ", i + 1);
            String equation = scanner.nextLine().trim();

            Map<String, Double> coefficients = parseEquation(equation, new String[]{"x", "y", "z"});
            A[i][0] = coefficients.getOrDefault("x", 0.0);
            A[i][1] = coefficients.getOrDefault("y", 0.0);
            A[i][2] = coefficients.getOrDefault("z", 0.0);
            B[i][0] = coefficients.get("constant");
        }

        try {
            double[] solution = SimulSolver.solve3x3(A, B);
            System.out.printf("Solution:\n x = %.6f, y = %.6f, z = %.6f\n", solution[0], solution[1], solution[2]);
        } catch (Exception e) {
            System.out.println("Error: " + e.getMessage());
        }
        pauseScreen();
    }

    private Map<String, Double> parseEquation(String equation, String[] variables) {
        Map<String, Double> coefficients = new HashMap<>();
        coefficients.put("constant", 0.0);

        equation = equation.replace(" ", "");
        String[] parts = equation.split("=");

        if (parts.length != 2) {
            throw new IllegalArgumentException("Invalid equation format. Use 'ax + by + cz = d'.");
        }

        String lhs = parts[0];
        double rhs = Double.parseDouble(parts[1]);

        String[] terms = lhs.split("(?=[+-])");

        for (String term : terms) {
            term = term.trim();
            if (term.isEmpty()) continue;

            boolean isVariable = false;

            for (String var : variables) {
                if (term.contains(var)) {
                    isVariable = true;
                    String coefficient = term.replace(var, "");
                    double value = coefficient.isEmpty() || coefficient.equals("+") ? 1.0
                            : coefficient.equals("-") ? -1.0 : Double.parseDouble(coefficient);
                    coefficients.put(var, coefficients.getOrDefault(var, 0.0) + value);
                    break;
                }
            }

            if (!isVariable) {
                coefficients.put("constant", coefficients.get("constant") + Double.parseDouble(term));
            }
        }

        coefficients.put("constant", coefficients.get("constant") - rhs);
        return coefficients;
    }

    private void clearScreen() {
        System.out.print("\033[H\033[2J");
        System.out.flush();
    }

    private void printBanner() {
        System.out.println("\033[1;32m\n===== Simultaneous Equation Solver =====\033[0m");
    }

    private void pauseScreen() {
        System.out.println("\nPress Enter to continue...");
        scanner.nextLine();
    }
}