/*
 * Copyright 1997-2006 Sun Microsystems, Inc.  All Rights Reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *   - Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *
 *   - Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *
 *   - Neither the name of Sun Microsystems nor the names of its
 *     contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
 * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/*
 */

import java.applet.Applet;
import java.awt.*;
import java.awt.event.*;
import java.io.*;
import java.lang.*;
import java.net.*;

public class SpreadSheet
    extends Applet
    implements MouseListener, KeyListener {
    String              title;
    Font                titleFont;
    Color               cellColor;
    Color               inputColor;
    int                 cellWidth = 100;
    int                 cellHeight = 15;
    int                 titleHeight = 15;
    int                 rowLabelWidth = 15;
    Font                inputFont;
    boolean             isStopped = false;
    boolean             fullUpdate = true;
    int                 rows;
    int                 columns;
    int                 currentKey = -1;
    int                 selectedRow = -1;
    int                 selectedColumn = -1;
    SpreadSheetInput    inputArea;
    Cell                cells[][];
    Cell                current = null;

    public synchronized void init() {
        String rs;

        cellColor = Color.white;
        inputColor = new Color(100, 100, 225);
        inputFont = new Font("Monospaced", Font.PLAIN, 10);
        titleFont = new Font("Monospaced", Font.BOLD, 12);
        title = getParameter("title");
        if (title == null) {
            title = "Spreadsheet";
        }
        rs = getParameter("rows");
        if (rs == null) {
            rows = 9;
        } else {
            rows = Integer.parseInt(rs);
        }
        rs = getParameter("columns");
        if (rs == null) {
            columns = 5;
        } else {
            columns = Integer.parseInt(rs);
        }
        cells = new Cell[rows][columns];
        char l[] = new char[1];
        for (int i=0; i < rows; i++) {
            for (int j=0; j < columns; j++) {

                cells[i][j] = new Cell(this,
                                       Color.lightGray,
                                       Color.black,
                                       cellColor,
                                       cellWidth - 2,
                                       cellHeight - 2);
                l[0] = (char)((int)'a' + j);
                rs = getParameter("" + new String(l) + (i+1));
                if (rs != null) {
                    cells[i][j].setUnparsedValue(rs);
                }
            }
        }

        Dimension d = getSize();
        inputArea = new SpreadSheetInput(null, this, d.width - 2, cellHeight - 1,
                                         inputColor, Color.white);
        resize(columns * cellWidth + rowLabelWidth,
               (rows + 3) * cellHeight + titleHeight);
        addMouseListener(this);
        addKeyListener(this);
    }

    public void setCurrentValue(float val) {
        if (selectedRow == -1 || selectedColumn == -1) {
            return;
        }
        cells[selectedRow][selectedColumn].setValue(val);
        repaint();
    }

    public void stop() {
        isStopped = true;
    }

    public void start() {
        isStopped = false;
    }

    public void destroy() {
        for (int i=0; i < rows; i++) {
            for (int j=0; j < columns; j++) {
                if (cells[i][j].type == Cell.URL) {
                    cells[i][j].updaterThread.stop();
                }
            }
        }
    }

    public void setCurrentValue(int type, String val) {
        if (selectedRow == -1 || selectedColumn == -1) {
            return;
        }
        cells[selectedRow][selectedColumn].setValue(type, val);
        repaint();
    }

    public void update(Graphics g) {
        if (! fullUpdate) {
            int cx, cy;

            g.setFont(titleFont);
            for (int i=0; i < rows; i++) {
                for (int j=0; j < columns; j++) {
                    if (cells[i][j].needRedisplay) {
                        cx = (j * cellWidth) + 2 + rowLabelWidth;
                        cy = ((i+1) * cellHeight) + 2 + titleHeight;
                        cells[i][j].paint(g, cx, cy);
                    }
                }
            }
        } else {
            paint(g);
            fullUpdate = false;
        }
    }

    public void recalculate() {
        int     i,j;

        //System.out.println("SpreadSheet.recalculate");
        for (i=0; i < rows; i++) {
            for (j=0; j < columns; j++) {
                if (cells[i][j] != null && cells[i][j].type == Cell.FORMULA) {
                    cells[i][j].setRawValue(evaluateFormula(cells[i][j].parseRoot));
                    cells[i][j].needRedisplay = true;
                }
            }
        }
        repaint();
    }

    public float evaluateFormula(Node n) {
        float   val = 0.0f;

        //System.out.println("evaluateFormula:");
        //n.print(3);
        if (n == null) {
            //System.out.println("Null node");
            return val;
        }
        switch (n.type) {
          case Node.OP:
            val = evaluateFormula(n.left);
            switch (n.op) {
              case '+':
                val += evaluateFormula(n.right);
                break;
              case '*':
                val *= evaluateFormula(n.right);
                break;
              case '-':
                val -= evaluateFormula(n.right);
                break;
              case '/':
                val /= evaluateFormula(n.right);
                break;
            }
            break;
          case Node.VALUE:
            //System.out.println("=>" + n.value);
            return n.value;
          case Node.CELL:
            if (n == null) {
                //System.out.println("NULL at 192");
            } else {
                if (cells[n.row][n.column] == null) {
                    //System.out.println("NULL at 193");
                } else {
                    //System.out.println("=>" + cells[n.row][n.column].value);
                    return cells[n.row][n.column].value;
                }
            }
        }

        //System.out.println("=>" + val);
        return val;
    }

    public synchronized void paint(Graphics g) {
        int i, j;
        int cx, cy;
        char l[] = new char[1];


        Dimension d = getSize();

        g.setFont(titleFont);
        i = g.getFontMetrics().stringWidth(title);
        g.drawString((title == null) ? "Spreadsheet" : title,
                     (d.width - i) / 2, 12);
        g.setColor(inputColor);
        g.fillRect(0, cellHeight, d.width, cellHeight);
        g.setFont(titleFont);
        for (i=0; i < rows+1; i++) {
            cy = (i+2) * cellHeight;
            g.setColor(getBackground());
            g.draw3DRect(0, cy, d.width, 2, true);
            if (i < rows) {
                g.setColor(Color.red);
                g.drawString("" + (i+1), 2, cy + 12);
            }
        }

        g.setColor(Color.red);
        cy = (rows+3) * cellHeight + (cellHeight / 2);
        for (i=0; i < columns; i++) {
            cx = i * cellWidth;
            g.setColor(getBackground());
            g.draw3DRect(cx + rowLabelWidth,
                          2 * cellHeight, 1, d.height, true);
            if (i < columns) {
                g.setColor(Color.red);
                l[0] = (char)((int)'A' + i);
                g.drawString(new String(l),
                             cx + rowLabelWidth + (cellWidth / 2),
                             cy);
            }
        }

        for (i=0; i < rows; i++) {
            for (j=0; j < columns; j++) {
                cx = (j * cellWidth) + 2 + rowLabelWidth;
                cy = ((i+1) * cellHeight) + 2 + titleHeight;
                if (cells[i][j] != null) {
                    cells[i][j].paint(g, cx, cy);
                }
            }
        }

        g.setColor(getBackground());
        g.draw3DRect(0, titleHeight,
                      d.width,
                      d.height - titleHeight,
                      false);
        inputArea.paint(g, 1, titleHeight + 1);
    }

      //1.1 event handling

  public void mouseClicked(MouseEvent e)
  {}

  public void mousePressed(MouseEvent e)
  {
    int x = e.getX();
    int y = e.getY();
    Cell cell;
    if (y < (titleHeight + cellHeight)) {
      selectedRow = -1;
      if (y <= titleHeight && current != null) {
        current.deselect();
        current = null;
      }
      e.consume();
    }
    if (x < rowLabelWidth) {
      selectedRow = -1;
      if (current != null) {
        current.deselect();
                current = null;
      }
      e.consume();

    }
    selectedRow = ((y - cellHeight - titleHeight) / cellHeight);
    selectedColumn = (x - rowLabelWidth) / cellWidth;
    if (selectedRow > rows ||
        selectedColumn >= columns) {
      selectedRow = -1;
      if (current != null) {
        current.deselect();
        current = null;
      }
    } else {
      if (selectedRow >= rows) {
        selectedRow = -1;
        if (current != null) {
          current.deselect();
          current = null;
        }
        e.consume();
      }
      if (selectedRow != -1) {
        cell = cells[selectedRow][selectedColumn];
        inputArea.setText(new String(cell.getPrintString()));
        if (current != null) {
          current.deselect();
        }
        current = cell;
        current.select();
        requestFocus();
        fullUpdate = true;
        repaint();
      }
      e.consume();
    }
  }

  public void mouseReleased(MouseEvent e)
  {}

  public void mouseEntered(MouseEvent e)
  {}

  public void mouseExited(MouseEvent e)
  {}

  public void keyPressed(KeyEvent e)
  {
  }

  public void keyTyped(KeyEvent e) {
    fullUpdate=true;
    inputArea.processKey(e);
    e.consume();
  }

  public void keyReleased(KeyEvent e)
  {}

  public String getAppletInfo() {
    return "Title: SpreadSheet \nAuthor: Sami Shaio \nA simple spread sheet.";
  }

  public String[][] getParameterInfo() {
    String[][] info = {
      {"title", "string", "The title of the spread sheet.  Default is 'Spreadsheet'"},
      {"rows", "int", "The number of rows.  Default is 9."},
      {"columns", "int", "The number of columns.  Default is 5."}
    };
    return info;
  }


}

class CellUpdater extends Thread {
    Cell        target;
    InputStream dataStream = null;
    StreamTokenizer tokenStream;

    public CellUpdater(Cell c) {
        super("cell updater");
        target = c;
    }

    public void run() {
        try {
            dataStream = new URL(target.app.getDocumentBase(),
                                 target.getValueString()).openStream();
            tokenStream = new StreamTokenizer(new BufferedReader(new InputStreamReader(dataStream)));
            tokenStream.eolIsSignificant(false);

            while (true) {
                switch (tokenStream.nextToken()) {
                case StreamTokenizer.TT_EOF:
                    dataStream.close();
                    return;
                default:
                    break;
                case StreamTokenizer.TT_NUMBER:
                    target.setTransientValue((float)tokenStream.nval);
                    if (! target.app.isStopped && ! target.paused) {
                        target.app.repaint();
                    }
                    break;
                }
                try {
                    Thread.sleep(2000);
                } catch (InterruptedException e) {
                    break;
                }
            }
        } catch (IOException e) {
            return;
        }
    }
}

class Cell {
    public static final int VALUE = 0;
    public static final int LABEL = 1;
    public static final int URL   = 2;
    public static final int FORMULA = 3;

    Node        parseRoot;
    boolean     needRedisplay;
    boolean selected = false;
    boolean transientValue = false;
    public int  type = Cell.VALUE;
    String      valueString = "";
    String      printString = "v";
    float       value;
    Color       bgColor;
    Color       fgColor;
    Color       highlightColor;
    int         width;
    int         height;
    SpreadSheet app;
    CellUpdater updaterThread;
    boolean     paused = false;

    public Cell(SpreadSheet app,
                Color bgColor,
                Color fgColor,
                Color highlightColor,
                int width,
                int height) {
        this.app = app;
        this.bgColor = bgColor;
        this.fgColor = fgColor;
        this.highlightColor = highlightColor;
        this.width = width;
        this.height = height;
        needRedisplay = true;
    }

    public void setRawValue(float f) {
        valueString = Float.toString(f);
        value = f;
    }
    public void setValue(float f) {
        setRawValue(f);
        printString = "v" + valueString;
        type = Cell.VALUE;
        paused = false;
        app.recalculate();
        needRedisplay = true;
    }

    public void setTransientValue(float f) {
        transientValue = true;
        value = f;
        needRedisplay = true;
        app.recalculate();
    }

    public void setUnparsedValue(String s) {
        switch (s.charAt(0)) {
          case 'v':
            setValue(Cell.VALUE, s.substring(1));
            break;
          case 'f':
            setValue(Cell.FORMULA, s.substring(1));
            break;
          case 'l':
            setValue(Cell.LABEL, s.substring(1));
            break;
          case 'u':
            setValue(Cell.URL, s.substring(1));
            break;
        }
    }

    /**
     * Parse a spreadsheet formula. The syntax is defined as:
     *
     * formula -> value
     * formula -> value op value
     * value -> '(' formula ')'
     * value -> cell
     * value -> <number>
     * op -> '+' | '*' | '/' | '-'
     * cell -> <letter><number>
     */
    public String parseFormula(String formula, Node node) {
        String subformula;
        String restFormula;
        float value;
        int length = formula.length();
        Node left;
        Node right;
        char op;

        if (formula == null) {
            return null;
        }
        subformula = parseValue(formula, node);
        //System.out.println("subformula = " + subformula);
        if (subformula == null || subformula.length() == 0) {
            //System.out.println("Parse succeeded");
            return null;
        }
        if (subformula == formula) {
            //System.out.println("Parse failed");
            return formula;
        }

        // parse an operator and then another value
        switch (op = subformula.charAt(0)) {
          case 0:
            //System.out.println("Parse succeeded");
            return null;
          case ')':
            //System.out.println("Returning subformula=" + subformula);
            return subformula;
          case '+':
          case '*':
          case '-':
          case '/':
            restFormula = subformula.substring(1);
            subformula = parseValue(restFormula, right=new Node());
            //System.out.println("subformula(2) = " + subformula);
            if (subformula != restFormula) {
                //System.out.println("Parse succeeded");
                left = new Node(node);
                node.left = left;
                node.right = right;
                node.op = op;
                node.type = Node.OP;
                //node.print(3);
                return subformula;
            } else {
                //System.out.println("Parse failed");
                return formula;
            }
          default:
            //System.out.println("Parse failed (bad operator): " + subformula);
            return formula;
        }
    }

    public String parseValue(String formula, Node node) {
        char    c = formula.charAt(0);
        String  subformula;
        String  restFormula;
        float   value;
        int     row;
        int     column;

        //System.out.println("parseValue: " + formula);
        restFormula = formula;
        if (c == '(') {
            //System.out.println("parseValue(" + formula + ")");
            restFormula = formula.substring(1);
            subformula = parseFormula(restFormula, node);
            //System.out.println("rest=(" + subformula + ")");
            if (subformula == null ||
                subformula.length() == restFormula.length()) {
                //System.out.println("Failed");
                return formula;
            } else if (! (subformula.charAt(0) == ')')) {
                //System.out.println("Failed (missing parentheses)");
                return formula;
            }
            restFormula = subformula;
        } else if (c >= '0' && c <= '9') {
            int i;

            //System.out.println("formula=" + formula);
            for (i=0; i < formula.length(); i++) {
                c = formula.charAt(i);
                if ((c < '0' || c > '9') && c != '.') {
                    break;
                }
            }
            try {
                value = Float.valueOf(formula.substring(0, i)).floatValue();
            } catch (NumberFormatException e) {
                //System.out.println("Failed (number format error)");
                return formula;
            }
            node.type = Node.VALUE;
            node.value = value;
            //node.print(3);
            restFormula = formula.substring(i);
            //System.out.println("value= " + value + " i=" + i +
                //                     " rest = " + restFormula);
            return restFormula;
        } else if (c >= 'A' && c <= 'Z') {
            int i;

            column = c - 'A';
            restFormula = formula.substring(1);
            for (i=0; i < restFormula.length(); i++) {
                c = restFormula.charAt(i);
                if (c < '0' || c > '9') {
                    break;
                }
            }
            row = Float.valueOf(restFormula.substring(0, i)).intValue();
            //System.out.println("row = " + row + " column = " + column);
            node.row = row - 1;
            node.column = column;
            node.type = Node.CELL;
            //node.print(3);
            if (i == restFormula.length()) {
                restFormula = null;
            } else {
                restFormula = restFormula.substring(i);
                if (restFormula.charAt(0) == 0) {
                    return null;
                }
            }
        }

        return restFormula;
    }


    public void setValue(int type, String s) {
        paused = false;
        if (this.type == Cell.URL) {
            updaterThread.stop();
            updaterThread = null;
        }

        valueString = new String(s);
        this.type = type;
        needRedisplay = true;
        switch (type) {
          case Cell.VALUE:
            setValue(Float.valueOf(s).floatValue());
            break;
          case Cell.LABEL:
            printString = "l" + valueString;
            break;
          case Cell.URL:
            printString = "u" + valueString;
            updaterThread = new CellUpdater(this);
            updaterThread.start();
            break;
          case Cell.FORMULA:
            parseFormula(valueString, parseRoot = new Node());
            printString = "f" + valueString;
            break;
        }
        app.recalculate();
    }

    public String getValueString() {
        return valueString;
    }

    public String getPrintString() {
        return printString;
    }

    public void select() {
        selected = true;
        paused = true;
    }
    public void deselect() {
        selected = false;
        paused = false;
        needRedisplay = true;
        app.repaint();
    }
    public void paint(Graphics g, int x, int y) {
        if (selected) {
            g.setColor(highlightColor);
        } else {
            g.setColor(bgColor);
        }
        g.fillRect(x, y, width - 1, height);
        if (valueString != null) {
            switch (type) {
              case Cell.VALUE:
              case Cell.LABEL:
                g.setColor(fgColor);
                break;
              case Cell.FORMULA:
                g.setColor(Color.red);
                break;
              case Cell.URL:
                g.setColor(Color.blue);
                break;
            }
            if (transientValue){
                g.drawString("" + value, x, y + (height / 2) + 5);
            } else {
                if (valueString.length() > 14) {
                    g.drawString(valueString.substring(0, 14),
                                 x, y + (height / 2) + 5);
                } else {
                    g.drawString(valueString, x, y + (height / 2) + 5);
                }
            }
        }
        needRedisplay = false;
    }
}

class Node {
    public static final int OP = 0;
    public static final int VALUE = 1;
    public static final int CELL = 2;

    int         type;
    Node        left;
    Node        right;
    int         row;
    int         column;
    float       value;
    char        op;

    public Node() {
        left = null;
        right = null;
        value = 0;
        row = -1;
        column = -1;
        op = 0;
        type = Node.VALUE;
    }
    public Node(Node n) {
        left = n.left;
        right = n.right;
        value = n.value;
        row = n.row;
        column = n.column;
        op = n.op;
        type = n.type;
    }
    public void indent(int ind) {
        for (int i = 0; i < ind; i++) {
            System.out.print(" ");
        }
    }
    public void print(int indentLevel) {
        char l[] = new char[1];
        indent(indentLevel);
        System.out.println("NODE type=" + type);
        indent(indentLevel);
        switch (type) {
          case Node.VALUE:
            System.out.println(" value=" + value);
            break;
          case Node.CELL:
            l[0] = (char)((int)'A' + column);
            System.out.println(" cell=" + new String(l) + (row+1));
            break;
          case Node.OP:
            System.out.println(" op=" + op);
            left.print(indentLevel + 3);
            right.print(indentLevel + 3);
            break;
        }
    }
}

class InputField {
    int         maxchars = 50;
    int         cursorPos = 0;
    Applet      app;
    String      sval;
    char        buffer[];
    int         nChars;
    int         width;
    int         height;
    Color       bgColor;
    Color       fgColor;

    public InputField(String initValue, Applet app, int width, int height,
                      Color bgColor, Color fgColor) {
        this.width = width;
        this.height = height;
        this.bgColor = bgColor;
        this.fgColor = fgColor;
        this.app = app;
        buffer = new char[maxchars];
        nChars = 0;
        if (initValue != null) {
            initValue.getChars(0, initValue.length(), this.buffer, 0);
            nChars = initValue.length();
        }
        sval = initValue;
    }

    public void setText(String val) {
        int i;

        for (i=0; i < maxchars; i++) {
            buffer[i] = 0;
        }
        if (val == null) {
            sval = "";
        } else {
            sval = val;
        }
        nChars = sval.length();
        sval.getChars(0, sval.length(), buffer, 0);
    }

    public String getValue() {
        return sval;
    }

    public void paint(Graphics g, int x, int y) {
        g.setColor(bgColor);
        g.fillRect(x, y, width, height);
        if (sval != null) {
            g.setColor(fgColor);
            g.drawString(sval, x, y + (height / 2) + 3);
        }
    }

    public void processKey(KeyEvent e) {
        char ch = e.getKeyChar();
        switch (ch) {
            case '\b': // delete
                if (nChars > 0) {
                    nChars--;
                    sval = new String(buffer, 0, nChars);
                }
                break;
            case '\n': // return
                selected();
                break;
            default:
                if (nChars < maxchars && ch >= '0') {
                    buffer[nChars++] = ch;
                    sval = new String(buffer, 0, nChars);
                }
        }
        app.repaint();
    }

    public void keyReleased(KeyEvent e) {
    }

    public void selected() {
    }
}

class SpreadSheetInput
    extends InputField {

  public SpreadSheetInput(String initValue,
                          SpreadSheet app,
                          int width,
                          int height,
                          Color bgColor,
                          Color fgColor) {
    super(initValue, app, width, height, bgColor, fgColor);
  }

    public void selected() {
        float f;
        sval = ("".equals(sval)) ? "v":sval;
        switch (sval.charAt(0)) {
          case 'v':
              String s= sval.substring(1);
            try {
                int i;
                for (i = 0; i < s.length(); i++) {
                    char c = s.charAt(i);
                    if (c < '0' || c > '9')
                        break;
                }
                s = s.substring(0, i);
                f = Float.valueOf(s).floatValue();
                ((SpreadSheet)app).setCurrentValue(f);
            } catch (NumberFormatException e) {
                System.out.println("Not a float: '" + s + "'");
            }
            break;
          case 'l':
            ((SpreadSheet)app).setCurrentValue(Cell.LABEL, sval.substring(1));
            break;
          case 'u':
            ((SpreadSheet)app).setCurrentValue(Cell.URL, sval.substring(1));
            break;
          case 'f':
            ((SpreadSheet)app).setCurrentValue(Cell.FORMULA, sval.substring(1));
            break;
        }
    }
}