package app;

// Java imports
import java.awt.*;
import java.util.*;
import javax.swing.*;

// Project imports
import vue.*;

// List of CPU registers
class RegisterList extends JScrollPane {

    // Package fields
    CPUWindow parent; // Containing CPU window

    // Private fields
    private boolean shown; // Component has been shown
    private HashMap<Integer, Register> registers; // Register items

    // UI components
    private JPanel client; // Client area



    ///////////////////////////////////////////////////////////////////////////
    //                             Constructors                              //
    ///////////////////////////////////////////////////////////////////////////

    // Default constructor
    RegisterList(CPUWindow parent, boolean system) {
        super(VERTICAL_SCROLLBAR_ALWAYS, HORIZONTAL_SCROLLBAR_AS_NEEDED);

        // Configure instance fields
        this.parent = parent;
        registers   = new HashMap<Integer, Register>();
        shown       = true;

        // Configure client area
        client = new JPanel(new GridBagLayout()) {
            public Dimension getPreferredSize() {
                var ret = super.getPreferredSize();
                if (!shown) ret.height = system ? getInitialHeight() : 0;
                return ret;
            }
            public void paintComponent(Graphics g) {
                shown = true;
                super.paintComponent(g);
            }
        };
        client.setBackground(SystemColor.window);
        client.setFocusable(true);

        // Initialize system registers
        if (system) {
            new Register(this, "PC"   , VUE.PC   , VUE.PC        );
            new Register(this, "PSW"  , VUE.PSW  , VUE.PSW       );
            new Register(this, "EIPC" , VUE.EIPC , Register.PLAIN);
            new Register(this, "EIPSW", VUE.EIPSW, VUE.PSW       );
            new Register(this, "FEPC" , VUE.FEPC , Register.PLAIN);
            new Register(this, "FEPSW", VUE.FEPSW, VUE.PSW       );
            new Register(this, "ECR"  , VUE.ECR  , VUE.ECR       );
            new Register(this, "ADTRE", VUE.ADTRE, Register.PLAIN);
            new Register(this, "CHCW" , VUE.CHCW , VUE.CHCW      );
            new Register(this, "PIR"  , VUE.PIR  , VUE.PIR       );
            new Register(this, "TKCW" , VUE.TKCW , VUE.TKCW      );
            new Register(this, "29"   ,        29, Register.PLAIN);
            new Register(this, "30"   ,        30, Register.PLAIN);
            new Register(this, "31"   ,        31, Register.PLAIN);
        }

        // Initialize program registers
        else for (int x = 0; x < 32; x++) {
            String name = null;
            switch (x) {
                case VUE.GP: name = "gp"; break;
                case VUE.HP: name = "hp"; break;
                case VUE.LP: name = "lp"; break;
                case VUE.SP: name = "sp"; break;
                case VUE.TP: name = "tp"; break;
            }
            new Register(this, name, x, Register.PROGRAM);
        }

        // List terminator
        var spacer = new JPanel(null);
        spacer.setOpaque(false);
        spacer.setPreferredSize(new Dimension(0, 0));
        var gbc = new GridBagConstraints();
        gbc.gridheight = GridBagConstraints.REMAINDER;
        gbc.gridwidth  = GridBagConstraints.REMAINDER;
        gbc.weighty    = 1;
        client.add(spacer, gbc);

        // Configure component
        shown = false;
        setViewportView(client);
    }



    ///////////////////////////////////////////////////////////////////////////
    //                            Public Methods                             //
    ///////////////////////////////////////////////////////////////////////////

    // Draw the component
    public void paintComponent(Graphics g) {
        if (!shown) {
            shown = true;
            revalidate();
        }
        super.paintComponent(g);
    }

    // Transfer focus to the client area
    public void requestFocus() {
        client.requestFocus();
    }

    // Recalculate layout
    public void revalidate() {
        if (client != null)
            client.revalidate();
        super.revalidate();
        repaint();
    }



    ///////////////////////////////////////////////////////////////////////////
    //                            Package Methods                            //
    ///////////////////////////////////////////////////////////////////////////

    // Add a register component to the client area
    void add(GridBagConstraints gbc, JComponent comp) {
        client.add(comp, gbc);
    }

    // Associate a register with its index
    void add(int index, Register register) {
        registers.put(index, register);
    }

    // Apply configuration settings
    void configure() {

        // Configure registers
        for (var reg : registers.values())
            reg.configure();

        // Configure component
        getVerticalScrollBar().setUnitIncrement(
            CPUWindow.regHexFontSize.height);
    }

    // Update the display
    void refresh() {
        for (var reg : registers.values())
            reg.refresh();
    }



    ///////////////////////////////////////////////////////////////////////////
    //                            Private Methods                            //
    ///////////////////////////////////////////////////////////////////////////

    // Determine the initial height upon first show
    private int getInitialHeight() {
        int height = 0;
        var layout = (GridBagLayout) client.getLayout();
        int ret    = 0;
        int row    = 0;

        // Process controls until the target row is found
        for (var control : client.getComponents()) {
            var ctrl = (JComponent) control;

            // Track the tallest control on the row
            if (ctrl.isVisible())
                height = Math.max(height, ctrl.getPreferredSize().height);

            // This is not the last control on the row
            if (layout.getConstraints(control).gridwidth !=
                GridBagConstraints.REMAINDER)
                continue;

            // Advance to the next row
            ret   += height;
            height = 0;
            row++;

            // The target row has been reached
            if (row == 4)
                break;
        }

        return ret;
    }

}