package edu.princeton.toy;

import java.awt.*;

import javax.swing.*;

import edu.princeton.swing.*;

/**
 * TReferencePane is a convenient subclass of JPanel which provides reference information regarding
 * the TOY language.
 *
 * @author btsang
 * @version 7.1
 */
public class TReferencePane extends JPanel
{
    /**
     * The text that is displayed in the reference text area.
     */
    public static final String REFERENCE_TEXT =
            "INSTRUCTION FORMATS\n" +
            "\n" +
            "           | .... | .... | .... | .... |\n" +
            "Format RR: |  op  |  d   |  s   |  t   |\n" +
            "Format A:  |  op  |  d   |     addr    |\n" +
            "\n" +
            "\n" +
            "ARITHMETIC and LOGICAL operations\n" +
            "  1: add              R[d] <- R[s] +  R[t]\n" +
            "  2: subtract         R[d] <- R[s] -  R[t]\n" +
            "  3: and              R[d] <- R[s] &  R[t]\n" +
            "  4: xor              R[d] <- R[s] ^  R[t]\n" +
            "  5: shift left       R[d] <- R[s] << R[t]\n" +
            "  6: shift right      R[d] <- R[s] >> R[t]\n" +
            "\n" +
            "TRANSFER between registers and memory\n" +
            "  7: load address     R[d] <- addr\n" +
            "  8: load             R[d] <- M[addr]\n" +
            "  9: store            M[addr] <- R[d]\n" +
            "  A: load indirect    R[d] <- M[R[t]]\n" +
            "  B: store indirect   M[R[t]] <- R[d]\n" +
            "\n" +
            "CONTROL\n" +
            "  0: halt             halt\n" +
            "  C: branch zero      if (R[d] == 0) PC <- addr\n" +
            "  D: branch positive  if (R[d] >  0) PC <- addr\n" +
            "  E: jump register    PC <- R[d]\n" +
            "  F: jump and link    R[d] <- PC; PC <- addr\n" +
            "\n" +
            "\n" +
            "Register 0 always reads 0.\n" +
            "Loads from M[FF] come from stdin.\n" +
            "Stores to  M[FF] go to stdout.\n" +
            "\n" +
            "16-bit registers (two's complement)\n" +
            "16-bit memory locations\n" +
            " 8-bit program counter\n";

    private JToolBar baseConverterToolbar;
    private Object lastToolbarLocation;

    /**
     * Constructs a new TReferencePane.
     */
    public TReferencePane()
    {
        super(new BorderLayout());

        {   // Prepare the base converter toolbar
            baseConverterToolbar = new JToolBar();
            baseConverterToolbar.setFont(null);
            {   // Prepare the base converter pane
                TBaseConverterPane baseConverterPane = new TBaseConverterPane();
                baseConverterPane.setFont(null);
                baseConverterToolbar.add(baseConverterPane);
            }

            lastToolbarLocation = BorderLayout.NORTH;
            add(baseConverterToolbar, BorderLayout.NORTH);
        }

        { // Prepare the language reference panel
            JPanel languageReferencePanel = new JPanel(new GridBagLayout());
            languageReferencePanel.setFont(null);

            languageReferencePanel.add(
                new JLabel("Language Reference"),
                new GridBagConstraints(
                    0, 0, 1, 1,
                    1.0, 0.0,
                    GridBagConstraints.NORTHWEST,
                    GridBagConstraints.NONE,
                    new Insets(2, 2, 2, 2),
                    0, 0
                    )
                );

            PTextArea referenceTextArea = new PTextArea(REFERENCE_TEXT);
            referenceTextArea.setEditable(false);
            referenceTextArea.setFont(null);

            JScrollPane scrollPane = new JScrollPane(
                referenceTextArea,
                JScrollPane.VERTICAL_SCROLLBAR_ALWAYS,
                JScrollPane.HORIZONTAL_SCROLLBAR_AS_NEEDED
                );
            scrollPane.setFont(null);
            scrollPane.getViewport().setFont(null);
            languageReferencePanel.add(
                scrollPane,
                new GridBagConstraints(
                    0, 1, 1, 1,
                    1.0, 1.0,
                    GridBagConstraints.NORTHWEST,
                    GridBagConstraints.BOTH,
                    new Insets(2, 2, 2, 2),
                    0, 0
                    )
                );

            add(languageReferencePanel, BorderLayout.CENTER);
        }
    }

    /**
     * Override setFont to pass the font onto the toolbar.
     */
    public void setFont(Font font)
    {
        if (baseConverterToolbar != null)
            baseConverterToolbar.setFont(font);

        super.setFont(font);
    }
    
    /**
     * Override addImpl to prevent the JToolbar from being placed in either the BorderLayout.EAST
     * or BorderLayout.WEST.
     */
    protected void addImpl(Component comp, Object constraints, int index)
    {
        if (comp == baseConverterToolbar)
        {
            if (constraints != BorderLayout.NORTH && constraints != BorderLayout.SOUTH)
            {
                constraints = lastToolbarLocation;
                baseConverterToolbar.setOrientation(JToolBar.HORIZONTAL);
            }
            else {
                lastToolbarLocation = constraints;
            }
        }

        super.addImpl(comp, constraints, index);
    }
}