/*
 * Copyright (c) 2003 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:
 * 
 * - Redistribution of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * 
 * - Redistribution 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, Inc. or the names of
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 * 
 * This software is provided "AS IS," without a warranty of any kind. ALL
 * EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES,
 * INCLUDING ANY IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A
 * PARTICULAR PURPOSE OR NON-INFRINGEMENT, ARE HEREBY EXCLUDED. SUN
 * MIDROSYSTEMS, INC. ("SUN") AND ITS LICENSORS SHALL NOT BE LIABLE FOR
 * ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING OR
 * DISTRIBUTING THIS SOFTWARE OR ITS DERIVATIVES. IN NO EVENT WILL SUN OR
 * ITS LICENSORS BE LIABLE FOR ANY LOST REVENUE, PROFIT OR DATA, OR FOR
 * DIRECT, INDIRECT, SPECIAL, CONSEQUENTIAL, INCIDENTAL OR PUNITIVE
 * DAMAGES, HOWEVER CAUSED AND REGARDLESS OF THE THEORY OF LIABILITY,
 * ARISING OUT OF THE USE OF OR INABILITY TO USE THIS SOFTWARE, EVEN IF
 * SUN HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
 * 
 * You acknowledge that this software is not designed or intended for use
 * in the design, construction, operation or maintenance of any nuclear
 * facility.
 * 
 * Sun gratefully acknowledges that this software was originally authored
 * and developed by Kenneth Bradley Russell and Christopher John Kline.
 */

package net.java.games.gluegen;

import java.util.*;
import java.io.*;

public abstract class FunctionEmitter
{
  public static final EmissionModifier STATIC = new EmissionModifier("static");

  private HashSet modifiers = new HashSet(4);
  private CommentEmitter commentEmitter = null;
  private PrintWriter defaultOutput;

  /**
   * Constructs the FunctionEmitter with a CommentEmitter that emits nothing.
   */
  public FunctionEmitter(PrintWriter defaultOutput)
  {
    assert(defaultOutput != null);
    this.defaultOutput = defaultOutput;
  }
  
  public PrintWriter getDefaultOutput() { return defaultOutput; }
  
  public void addModifiers(Iterator/*<EmissionModifier>*/ mi)
  {
    while (mi.hasNext())
    {
      modifiers.add((EmissionModifier) mi.next());
    }
  }
  public void addModifier(EmissionModifier m) { modifiers.add(m); }

  public boolean removeModifier(EmissionModifier m) { return modifiers.remove(m); }

  public void clearModifiers() { modifiers.clear(); }

  public boolean hasModifier(EmissionModifier m) { return modifiers.contains(m); }

  public Iterator getModifiers() { return modifiers.iterator(); }

  public abstract String getName();

  /**
   * Emit the function to the specified output (instead of the default
   * output).
   */
  public void emit(PrintWriter output)
  {
    emitDocComment(output);
    //output.println("  // Emitter: " + getClass().getName());
    emitSignature(output);
    emitBody(output);
  }

  /**
   * Emit the function to the default output (the output that was passed to
   * the constructor)
   */
  public final void emit()
  {
    emit(getDefaultOutput());
  }

  /** Returns, as a String, whatever {@link #emit} would output. */
  public String toString()
  {
    StringWriter sw = new StringWriter(500);
    PrintWriter w = new PrintWriter(sw);
    emit(w);
    return sw.toString();
  }

  /**
   * Set the object that will emit the comment for this function. If the
   * parameter is null, no comment will be emitted.
   */
  public void setCommentEmitter(CommentEmitter cEmitter)
  {
    commentEmitter = cEmitter;
  }

  /**
   * Get the comment emitter for this FunctionEmitter. The return value may be
   * null, in which case no comment emitter has been set.
   */
  public CommentEmitter getCommentEmitter() { return commentEmitter; }
  
  protected void emitDocComment(PrintWriter writer)
  {
    if (commentEmitter != null)
    {
      writer.print(getBaseIndentString()); //indent

      writer.print(getCommentStartString());

      commentEmitter.emit(this, writer);

      writer.print(getBaseIndentString()); //indent
      
      writer.println(getCommentEndString());
    }
  }
  
  protected void emitSignature(PrintWriter writer)
  {
    writer.print(getBaseIndentString()); // indent method

    int numEmitted = emitModifiers(writer);
    if (numEmitted > 0)
    {
      writer.print(" ");
    }

    emitReturnType(writer);
    writer.print(" ");

    emitName(writer);
    writer.print("(");

    emitArguments(writer);
    writer.print(")");
  }

  protected int emitModifiers(PrintWriter writer)
  {
    PrintWriter w = getDefaultOutput();
    int numEmitted = 0;
    for (Iterator it = getModifiers(); it.hasNext(); )
    {
      writer.print(it.next());
      ++numEmitted;
      if (it.hasNext())
      {
        writer.print(" ");
      }
    }
    return numEmitted;
  }

  protected String getBaseIndentString() { return ""; }
  
  protected String getCommentStartString() { return "/* "; }
  protected String getCommentEndString() { return " */"; }
  
  protected abstract void emitReturnType(PrintWriter writer);
  protected abstract void emitName(PrintWriter writer); 
  /** Returns the number of arguments emitted. */
  protected abstract int emitArguments(PrintWriter writer);  
  protected abstract void emitBody(PrintWriter writer);
  
  public static class EmissionModifier
  {    
    public final String toString() { return emittedForm; }
    
    private String emittedForm;
    protected EmissionModifier(String emittedForm) { this.emittedForm = emittedForm; } 
  }
}