/*
 * Created on 20 juin 2005
 *
 */
package fr.umlv.table.spread;

import java.awt.Component;
import java.util.HashMap;
import java.util.HashSet;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import javax.script.Bindings;
import javax.script.Compilable;
import javax.script.CompiledScript;
import javax.script.ScriptEngine;
import javax.script.ScriptEngineManager;
import javax.script.ScriptException;
import javax.script.SimpleBindings;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.table.AbstractTableModel;
import javax.swing.table.DefaultTableCellRenderer;

public class SpreadTheWorld {
  private static class Cell {
    final String text;
    final CompiledScript script;
    public Cell(String text,CompiledScript script) {
      this.text=text;
      this.script=script;
    }
    @Override
    public String toString() {
      return text;
    }
  }
  
  private class CellBindings extends SimpleBindings {
    CellBindings() {
      // call from the outer class
    }
    
    @Override
    public boolean containsKey(Object key) {
      return CELL_REF_PATTERN.matcher(key.toString()).matches() ||
        super.containsKey(key);
    }
    
    @Override
    public Object get(Object key) {
      Matcher matcher=CELL_REF_PATTERN.matcher(key.toString());
      if (!matcher.matches())
        return super.get(key);
      Cell cell=getCell(Integer.parseInt(matcher.group(2)),
        getColumnIndexFromName(matcher.group(1)));
      if (cell==null)
        return 0;
      return eval(cell);
    }
  }
  
  static final Pattern CELL_REF_PATTERN=Pattern.compile("(\\p{Alpha}+)(\\p{Digit}+)");
  
  private class ExCellTableModel extends AbstractTableModel {
    ExCellTableModel() {
      // call from the outer class
    }
    public int getRowCount() {
      return 1000;
    }
    public int getColumnCount() {
      return 100;
    }
    public Object getValueAt(int row, int column) {
      return getCell(row,column);
    }
    @Override
    public boolean isCellEditable(int row, int column) {
      return true;
    }
    @Override
    public void setValueAt(Object aValue, int row, int column) {
      String text=aValue.toString();
      CompiledScript script=null;
      try {
        script = compilable.compile(text);
      } catch (ScriptException e) {
        e.printStackTrace();
        return;
      }
      setCell(row,column,text,script);
      // not efficient !!!
      fireTableDataChanged();
    }
  }
  
  //swing is single-threaded !!
  private transient HashSet<Cell> circularity=
    new HashSet<Cell>();
  
  private final Bindings bindings=new CellBindings();
  final Compilable compilable;
  
  public SpreadTheWorld(ScriptEngine engine) {
    this.compilable=(Compilable)engine;
  }
  
  Object eval(Cell cell) {
    if (cell.script==null)
      return cell.text;
    
    if (!circularity.add(cell)) {
      throw new IllegalStateException("circular refs");
    }
    try {
      return cell.script.eval(bindings);
    } catch (ScriptException e) {
      return e;
    } finally {
      circularity.remove(cell);
    }
  }
  
  Cell getCell(int row,int column) {
    return cellMap.get(mangle(row,column));
  }
  
  void setCell(int row,int column,String text,CompiledScript script) {
    cellMap.put(mangle(row,column),new Cell(text,script));
  }
  
  private static long mangle(int row,int column) {
    return (((long)row)<<32)+column;
  }
  
  private final HashMap<Long,Cell> cellMap=
    new HashMap<Long,Cell>();
  
  
  
  static int getColumnIndexFromName(String columnName) {
    int value=0;
    for(int i=0;i<columnName.length();i++) {
      value=value*26+Character.toLowerCase(columnName.charAt(i))-'a';
    }
    return value;
  }
  
  public static void main(String[] args) {
    ScriptEngineManager manager=new ScriptEngineManager();
    ScriptEngine engine=manager.getEngineByExtension("js");
    
    final SpreadTheWorld application=new SpreadTheWorld(engine);
    JTable table=new JTable(application.new ExCellTableModel());
    table.setAutoResizeMode(JTable.AUTO_RESIZE_OFF);
    table.setDefaultRenderer(Object.class,new DefaultTableCellRenderer() {
      @Override
      public Component getTableCellRendererComponent(JTable table, Object value, boolean isSelected, boolean hasFocus, int row, int column) {
        Cell cell=application.getCell(row,column);
        return super.getTableCellRendererComponent(table,
            (cell==null)?null:application.eval(cell),
            isSelected, hasFocus, row, column);
      }
    });
    
    JFrame frame=new JFrame("Spread the World");
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setContentPane(new JScrollPane(table));
    frame.pack();
    frame.setVisible(true);
  }
}