Main.java

import javafx.application.Application;
import javafx.collections.FXCollections;
import javafx.collections.ObservableList;
import javafx.geometry.Insets;
import javafx.geometry.Pos;
import javafx.scene.Scene;
import javafx.scene.chart.PieChart;
import javafx.scene.control.*;
import javafx.scene.control.cell.PropertyValueFactory;
import javafx.scene.layout.*;
import javafx.scene.paint.Color;
import javafx.scene.shape.Circle;
import javafx.scene.text.Font;
import javafx.scene.text.FontWeight;
import javafx.stage.Modality;
import javafx.stage.Stage;

import java.util.HashMap;
import java.util.Map;

public class Main extends Application {

    private final ExpenseRepository repo = new ExpenseRepository();
    private Stage primaryStage; // We keep a reference to the main window

    // Chart Colors
    private final String[] PIE_COLORS = {
            "#fdcb6e", "#ff7675", "#74b9ff", "#55efc4", "#a29bfe", "#fab1a0"
    };

    public static void main(String[] args) {
        launch(args);
    }

    @Override
    public void start(Stage stage) {
        this.primaryStage = stage;
        showLoginScreen(); // Start with the login screen
    }

    // ==========================================
    // 1. THE LOGIN SCREEN (Gateway)
    // ==========================================
    private void showLoginScreen() {
        VBox root = new VBox(20);
        root.setAlignment(Pos.CENTER);
        root.setPadding(new Insets(40));

        Label lblTitle = new Label("Expense Tracker Login");
        lblTitle.getStyleClass().add("header-label");
        lblTitle.setStyle("-fx-font-size: 24px; -fx-text-fill: #6c5ce7;");

        Button btnUser = new Button("Login as User");
        Button btnAdmin = new Button("Login as Admin");

        // Set actions to switch screens
        btnUser.setOnAction(e -> showUserInterface());
        // Instead of going straight to Admin, we ask for password first
        btnAdmin.setOnAction(e -> askForAdminPassword());

        root.getChildren().addAll(lblTitle, btnUser, btnAdmin);

        Scene scene = new Scene(root, 400, 300);
        // Load CSS safely
        try {
            scene.getStylesheets().add(getClass().getResource("styles.css").toExternalForm());
        } catch (Exception e) { System.out.println("CSS not found!"); }

        primaryStage.setTitle("Welcome");
        primaryStage.setScene(scene);
        primaryStage.show();
    }

    // ==========================================
    // 2. THE USER INTERFACE (Clean & Pretty)
    // ==========================================
    private void showUserInterface() {
        VBox root = new VBox(20);
        root.setAlignment(Pos.CENTER);
        root.setPadding(new Insets(40));

        Label lblTitle = new Label("💰 My Expenses");
        lblTitle.getStyleClass().add("header-label");

        Button btnAdd = new Button("Add Expense");
        Button btnChart = new Button("View Analytics");
        Button btnLogout = new Button("Logout");
        btnLogout.setStyle("-fx-background-color: #b2bec3;"); // Grey for logout

        btnAdd.setOnAction(e -> showAddPopup());
        btnChart.setOnAction(e -> showChartPopup());
        btnLogout.setOnAction(e -> showLoginScreen()); // Go back

        root.getChildren().addAll(lblTitle, btnAdd, btnChart, btnLogout);

        Scene scene = new Scene(root, 400, 350);
        scene.getStylesheets().add(getClass().getResource("styles.css").toExternalForm());

        primaryStage.setTitle("User Mode");
        primaryStage.setScene(scene);
    }

    // ==========================================
    // 3. THE ADMIN INTERFACE (Table & Delete)
    // ==========================================
    private void showAdminInterface() {
        BorderPane root = new BorderPane();

        // --- Left: Table ---
        TableView<Expense> table = new TableView<>();

        TableColumn<Expense, String> colDesc = new TableColumn<>("Description");
        colDesc.setCellValueFactory(new PropertyValueFactory<>("description"));

        TableColumn<Expense, Double> colAmount = new TableColumn<>("Amount");
        colAmount.setCellValueFactory(new PropertyValueFactory<>("amount"));

        TableColumn<Expense, String> colCat = new TableColumn<>("Category");
        colCat.setCellValueFactory(new PropertyValueFactory<>("category"));

        table.getColumns().addAll(colDesc, colAmount, colCat);
        table.setItems(FXCollections.observableArrayList(repo.getAll())); // Load Data
        table.setColumnResizePolicy(TableView.CONSTRAINED_RESIZE_POLICY);

        VBox leftBox = new VBox(10, new Label("Database Records"), table);
        leftBox.setPadding(new Insets(10));
        leftBox.setPrefWidth(350);

        // --- Right: Controls ---
        Button btnDelete = new Button("Delete Selected");
        btnDelete.setStyle("-fx-background-color: #ff7675;");

        Button btnLogout = new Button("Logout");
        btnLogout.setStyle("-fx-background-color: #b2bec3;");

        // Delete Logic
        btnDelete.setOnAction(e -> {
            Expense selected = table.getSelectionModel().getSelectedItem();
            if (selected != null) {
                repo.delete(selected);
                table.setItems(FXCollections.observableArrayList(repo.getAll())); // Refresh
            }
        });

        btnLogout.setOnAction(e -> showLoginScreen());

        VBox rightBox = new VBox(20, new Label("Admin Controls"), btnDelete, btnLogout);
        rightBox.setAlignment(Pos.CENTER);
        rightBox.setPadding(new Insets(20));

        root.setCenter(leftBox);
        root.setRight(rightBox);

        Scene scene = new Scene(root, 600, 400);
        scene.getStylesheets().add(getClass().getResource("styles.css").toExternalForm());

        primaryStage.setTitle("Admin Dashboard");
        primaryStage.setScene(scene);
    }

    // ==========================================
    // HELPERS (Popups & Charts from before)
    // ==========================================

    private void showAddPopup() {
        Stage popup = new Stage();
        popup.initModality(Modality.APPLICATION_MODAL);
        popup.setTitle("Add New Expense");

        TextField txtDesc = new TextField(); txtDesc.setPromptText("Description");
        TextField txtAmount = new TextField(); txtAmount.setPromptText("Amount");
        TextField txtCat = new TextField(); txtCat.setPromptText("Category");
        Button btnSave = new Button("Save");

        VBox layout = new VBox(10, new Label("New Entry"), txtDesc, txtAmount, txtCat, btnSave);
        layout.setPadding(new Insets(20));
        layout.setAlignment(Pos.CENTER);

        btnSave.setOnAction(e -> {
            try {
                repo.add(new Expense(txtDesc.getText(), Double.parseDouble(txtAmount.getText()), txtCat.getText()));
                popup.close();
            } catch(Exception ex) { /* Ignore */ }
        });

        Scene scene = new Scene(layout, 300, 250);
        scene.getStylesheets().add(getClass().getResource("styles.css").toExternalForm());
        popup.setScene(scene);
        popup.show();
    }

    private void showChartPopup() {
        Stage chartStage = new Stage();
        PieChart chart = new PieChart();
        chart.setLabelsVisible(true);
        chart.setLegendVisible(false);

        Map<String, Double> catTotals = new HashMap<>();
        double grandTotal = 0;
        for (Expense e : repo.getAll()) {
            catTotals.put(e.category, catTotals.getOrDefault(e.category, 0.0) + e.amount);
            grandTotal += e.amount;
        }

        ObservableList<PieChart.Data> data = FXCollections.observableArrayList();
        for (Map.Entry<String, Double> entry : catTotals.entrySet()) {
            data.add(new PieChart.Data(entry.getKey(), entry.getValue()));
        }
        chart.setData(data);

        // Donut Hole
        Circle hole = new Circle(100);
        hole.setFill(Color.web("#f4f4f9"));
        Label totalLabel = new Label(String.format("Total\n$%.2f", grandTotal));
        totalLabel.setStyle("-fx-font-size: 18px; -fx-font-weight: bold;");

        StackPane stack = new StackPane(chart, hole, totalLabel);
        Scene scene = new Scene(stack, 500, 500);
        scene.getStylesheets().add(getClass().getResource("styles.css").toExternalForm());

        chartStage.setScene(scene);
        chartStage.show();

        // Apply Colors
        int i = 0;
        for (PieChart.Data d : data) {
            d.getNode().setStyle("-fx-pie-color: " + PIE_COLORS[i % PIE_COLORS.length] + ";");
            i++;
        }
    }

    // --- NEW: ADMIN PASSWORD POPUP ---
    private void askForAdminPassword() {
        Stage popup = new Stage();
        popup.initModality(Modality.APPLICATION_MODAL); // Block other windows
        popup.setTitle("Security Check");

        Label lbl = new Label("Enter Admin PIN:");
        lbl.setStyle("-fx-font-weight: bold; -fx-text-fill: #2d3436;");

        // PasswordField hides the text with dots
        PasswordField txtPass = new PasswordField();
        txtPass.setPromptText("PIN");
        txtPass.setStyle("-fx-max-width: 150px;");

        Button btnLogin = new Button("Unlock");

        Label lblError = new Label(); // Hidden error message
        lblError.setTextFill(Color.RED);

        // Action: Check the password
        btnLogin.setOnAction(e -> {
            String input = txtPass.getText();

            // THE SECRET PASSWORD IS "1234"
            if (input.equals("1234")) {
                popup.close();         // Close the password window
                showAdminInterface();  // Open the Admin Dashboard
            } else {
                lblError.setText("Wrong PIN! Try again.");
                txtPass.clear();
            }
        });

        VBox layout = new VBox(15, lbl, txtPass, lblError, btnLogin);
        layout.setAlignment(Pos.CENTER);
        layout.setPadding(new Insets(20));

        Scene scene = new Scene(layout, 250, 200);

        // Try to load CSS if available
        try { scene.getStylesheets().add(getClass().getResource("styles.css").toExternalForm()); }
        catch (Exception ex) { /* ignore */ }

        popup.setScene(scene);
        popup.show();
    }

}