// MessageFormat.java - Localized message formatting.

/* Copyright (C) 1999, 2001  Free Software Foundation

   This file is part of libgcj.

This software is copyrighted work licensed under the terms of the
Libgcj License.  Please consult the file "LIBGCJ_LICENSE" for
details.  */

package java.text;

import java.util.Date;
import java.util.Locale;
import java.util.Vector;

/**
 * @author Tom Tromey <tromey@cygnus.com>
 * @date March 3, 1999
 */
/* Written using "Java Class Libraries", 2nd edition, plus online
 * API docs for JDK 1.2 from http://www.javasoft.com.
 * Status:  Believed complete and correct to 1.2, except serialization.
 *          and parsing.
 */

final class MessageFormatElement
{
  // Argument number.
  int argNumber;
  // Formatter to be used.  This is the format set by setFormat.
  Format setFormat;
  // Formatter to be used based on the type.
  Format format;

  // Argument will be checked to make sure it is an instance of this
  // class.
  Class formatClass;

  // Formatter type.
  String type;
  // Formatter style.
  String style;

  // Text to follow this element.
  String trailer;

  // Recompute the locale-based formatter.
  void setLocale (Locale loc)
    {
      if (type == null)
	;
      else if (type.equals("number"))
	{
	  formatClass = java.lang.Number.class;

	  if (style == null)
	    format = NumberFormat.getInstance(loc);
	  else if (style.equals("currency"))
	    format = NumberFormat.getCurrencyInstance(loc);
	  else if (style.equals("percent"))
	    format = NumberFormat.getPercentInstance(loc);
	  else if (style.equals("integer"))
	    {
	      NumberFormat nf = NumberFormat.getNumberInstance(loc);
	      nf.setMaximumFractionDigits(0);
	      nf.setGroupingUsed(false);
	      format = nf;
	    }
	  else
	    {
	      format = NumberFormat.getNumberInstance(loc);
	      DecimalFormat df = (DecimalFormat) format;
	      try
		{
		  df.applyPattern(style);
		}
	      catch (ParseException x)
		{
		  throw new IllegalArgumentException (x.getMessage());
		}
	    }
	}
      else if (type.equals("time") || type.equals("date"))
	{
	  formatClass = java.util.Date.class;

	  int val = DateFormat.DEFAULT;
	  if (style == null)
	    ;
	  else if (style.equals("short"))
	    val = DateFormat.SHORT;
	  else if (style.equals("medium"))
	    val = DateFormat.MEDIUM;
	  else if (style.equals("long"))
	    val = DateFormat.LONG;
	  else if (style.equals("full"))
	    val = DateFormat.FULL;

	  if (type.equals("time"))
	    format = DateFormat.getTimeInstance(val, loc);
	  else
	    format = DateFormat.getDateInstance(val, loc);

	  if (style != null && val == DateFormat.DEFAULT)
	    {
	      SimpleDateFormat sdf = (SimpleDateFormat) format;
	      sdf.applyPattern(style);
	    }
	}
      else if (type.equals("choice"))
	{
	  formatClass = java.lang.Number.class;

	  if (style == null)
	    throw new
	      IllegalArgumentException ("style required for choice format");
	  format = new ChoiceFormat (style);
	}
    }
}

public class MessageFormat extends Format
{
  // Helper that returns the text up to the next format opener.  The
  // text is put into BUFFER.  Returns index of character after end of
  // string.  Throws IllegalArgumentException on error.
  private static final int scanString (String pat, int index,
				       StringBuffer buffer)
    {
      int max = pat.length();
      buffer.setLength(0);
      for (; index < max; ++index)
	{
	  char c = pat.charAt(index);
	  if (c == '\'' && index + 2 < max && pat.charAt(index + 2) == '\'')
	    {
	      buffer.append(pat.charAt(index + 1));
	      index += 2;
	    }
	  else if (c == '\'' && index + 1 < max
		   && pat.charAt(index + 1) == '\'')
	    {
	      buffer.append(c);
	      ++index;
	    }
	  else if (c == '{')
	    break;
	  else if (c == '}')
	    throw new IllegalArgumentException ();
	  else
	    buffer.append(c);
	}
      return index;
    }

  // This helper retrieves a single part of a format element.  Returns
  // the index of the terminating character.
  private static final int scanFormatElement (String pat, int index,
					      StringBuffer buffer,
					      char term)
    {
      int max = pat.length();
      buffer.setLength(0);
      int brace_depth = 1;

      for (; index < max; ++index)
	{
	  char c = pat.charAt(index);
	  if (c == '\'' && index + 2 < max && pat.charAt(index + 2) == '\'')
	    {
	      buffer.append(c);
	      buffer.append(pat.charAt(index + 1));
	      buffer.append(c);
	      index += 2;
	    }
	  else if (c == '\'' && index + 1 < max
		   && pat.charAt(index + 1) == '\'')
	    {
	      buffer.append(c);
	      ++index;
	    }
	  else if (c == '{')
	    {
	      buffer.append(c);
	      ++brace_depth;
	    }
	  else if (c == '}')
	    {
	      if (--brace_depth == 0)
		break;
	      buffer.append(c);
	    }
	  // Check for TERM after braces, because TERM might be `}'.
	  else if (c == term)
	    break;
	  else
	    buffer.append(c);
	}
      return index;
    }

  // This is used to parse a format element and whatever non-format
  // text might trail it.
  private static final int scanFormat (String pat, int index,
				       StringBuffer buffer, Vector elts,
				       Locale locale)
    {
      MessageFormatElement mfe = new MessageFormatElement ();
      elts.addElement(mfe);

      int max = pat.length();

      // Skip the opening `{'.
      ++index;

      // Fetch the argument number.
      index = scanFormatElement (pat, index, buffer, ',');
      try
	{
	  mfe.argNumber = Integer.parseInt(buffer.toString());
	}
      catch (NumberFormatException nfx)
	{
	  throw new IllegalArgumentException ();
	}

      // Extract the element format.
      if (index < max && pat.charAt(index) == ',')
	{
	  index = scanFormatElement (pat, index + 1, buffer, ',');
	  mfe.type = buffer.toString();

	  // Extract the style.
	  if (index < max && pat.charAt(index) == ',')
	    {
	      index = scanFormatElement (pat, index + 1, buffer, '}');
	      mfe.style = buffer.toString ();
	    }
	}

      // Advance past the last terminator.
      if (index >= max || pat.charAt(index) != '}')
	throw new IllegalArgumentException ();
      ++index;

      // Now fetch trailing string.
      index = scanString (pat, index, buffer);
      mfe.trailer = buffer.toString ();

      mfe.setLocale(locale);

      return index;
    }

  public void applyPattern (String newPattern)
    {
      pattern = newPattern;

      StringBuffer tempBuffer = new StringBuffer ();

      int index = scanString (newPattern, 0, tempBuffer);
      leader = tempBuffer.toString();

      Vector elts = new Vector ();
      while (index < newPattern.length())
	index = scanFormat (newPattern, index, tempBuffer, elts, locale);

      elements = new MessageFormatElement[elts.size()];
      elts.copyInto(elements);
    }

  public Object clone ()
    {
      MessageFormat c = new MessageFormat ();
      c.setLocale(locale);
      c.applyPattern(pattern);
      return (Object) c;
    }

  public boolean equals (Object obj)
    {
      if (! (obj instanceof MessageFormat))
	return false;
      MessageFormat mf = (MessageFormat) obj;
      return (pattern.equals(mf.pattern)
	      && locale.equals(mf.locale));
    }

  public static String format (String pattern, Object arguments[])
    {
      MessageFormat mf = new MessageFormat (pattern);
      StringBuffer sb = new StringBuffer ();
      FieldPosition fp = new FieldPosition (NumberFormat.INTEGER_FIELD);
      return mf.format(arguments, sb, fp).toString();
    }

  public final StringBuffer format (Object arguments[], StringBuffer appendBuf,
				    FieldPosition ignore)
    {
      appendBuf.append(leader);

      for (int i = 0; i < elements.length; ++i)
	{
	  if (elements[i].argNumber >= arguments.length)
	    throw new IllegalArgumentException ();
	  Object thisArg = arguments[elements[i].argNumber];

	  Format formatter = null;
	  if (elements[i].setFormat != null)
	    formatter = elements[i].setFormat;
	  else if (elements[i].format != null)
	    {
	      if (elements[i].formatClass != null
		  && ! elements[i].formatClass.isInstance(thisArg))
		throw new IllegalArgumentException ();
	      formatter = elements[i].format;
	    }
	  else if (thisArg instanceof Number)
	    formatter = NumberFormat.getInstance(locale);
	  else if (thisArg instanceof Date)
	    formatter = DateFormat.getTimeInstance(DateFormat.DEFAULT, locale);
	  else
	    appendBuf.append(thisArg);

	  if (formatter != null)
	    {
	      // Special-case ChoiceFormat.
	      if (formatter instanceof ChoiceFormat)
		{
		  StringBuffer buf = new StringBuffer ();
		  // FIXME: don't actually know what is correct here.
		  // Can a sub-format refer to any argument, or just
		  // the single argument passed to it?  Must test
		  // against JDK.
		  formatter.format(thisArg, buf, ignore);
		  MessageFormat mf = new MessageFormat ();
		  mf.setLocale(locale);
		  mf.applyPattern(buf.toString());
		  formatter = mf;
		}
	      formatter.format(thisArg, appendBuf, ignore);
	    }

	  appendBuf.append(elements[i].trailer);
	}

      return appendBuf;
    }

  public final StringBuffer format (Object singleArg, StringBuffer appendBuf,
				    FieldPosition ignore)
    {
      Object[] args;

      if (singleArg instanceof Object[])
	{
	  // This isn't specified in any manual, but it follows the
	  // JDK implementation.
	  args = (Object[]) singleArg;
	}
      else
	{
	  args = new Object[1];
	  args[0] = singleArg;
	}
      return format (args, appendBuf, ignore);
    }

  public Format[] getFormats ()
    {
      Format[] f = new Format[elements.length];
      for (int i = elements.length - 1; i >= 0; --i)
	f[i] = elements[i].setFormat;
      return f;
    }

  public Locale getLocale ()
    {
      return locale;
    }

  public int hashCode ()
    {
      // FIXME: not a very good hash.
      return pattern.hashCode() + locale.hashCode();
    }

  private MessageFormat ()
    {
    }

  public MessageFormat (String pattern)
    {
      locale = Locale.getDefault();
      applyPattern (pattern);
    }

  public Object[] parse (String sourceStr, ParsePosition pos)
    {
      // Check initial text.
      int index = pos.getIndex();
      if (! sourceStr.startsWith(leader, index))
	{
	  pos.setErrorIndex(index);
	  return null;
	}
      index += leader.length();

      Vector results = new Vector (elements.length, 1);
      // Now check each format.
      for (int i = 0; i < elements.length; ++i)
	{
	  Format formatter = null;
	  if (elements[i].setFormat != null)
	    formatter = elements[i].setFormat;
	  else if (elements[i].format != null)
	    formatter = elements[i].format;

	  Object value = null;
	  if (formatter instanceof ChoiceFormat)
	    {
	      // We must special-case a ChoiceFormat because it might
	      // have recursive formatting.
	      ChoiceFormat cf = (ChoiceFormat) formatter;
	      String[] formats = (String[]) cf.getFormats();
	      double[] limits = (double[]) cf.getLimits();
	      MessageFormat subfmt = new MessageFormat ();
	      subfmt.setLocale(locale);
	      ParsePosition subpos = new ParsePosition (index);

	      int j;
	      for (j = 0; value == null && j < limits.length; ++j)
		{
		  subfmt.applyPattern(formats[j]);
		  subpos.setIndex(index);
		  value = subfmt.parse(sourceStr, subpos);
		}
	      if (value != null)
		{
		  index = subpos.getIndex();
		  value = new Double (limits[j]);
		}
	    }
	  else if (formatter != null)
	    {
	      pos.setIndex(index);
	      value = formatter.parseObject(sourceStr, pos);
	      if (value != null)
		index = pos.getIndex();
	    }
	  else
	    {
	      // We have a String format.  This can lose in a number
	      // of ways, but we give it a shot.
	      int next_index = sourceStr.indexOf(elements[i].trailer, index);
	      if (next_index == -1)
		{
		  pos.setErrorIndex(index);
		  return null;
		}
	      value = sourceStr.substring(index, next_index);
	      index = next_index;
	    }

	  if (value == null
	      || ! sourceStr.startsWith(elements[i].trailer, index))
	    {
	      pos.setErrorIndex(index);
	      return null;
	    }

	  if (elements[i].argNumber >= results.size())
	    results.setSize(elements[i].argNumber + 1);
	  results.setElementAt(value, elements[i].argNumber);

	  index += elements[i].trailer.length();
	}

      Object[] r = new Object[results.size()];
      results.copyInto(r);
      return r;
    }

  public Object[] parse (String sourceStr) throws ParseException
    {
      ParsePosition pp = new ParsePosition (0);
      Object[] r = parse (sourceStr, pp);
      if (r == null)
	throw new ParseException ("couldn't parse string", pp.getErrorIndex());
      return r;
    }

  public Object parseObject (String sourceStr, ParsePosition pos)
    {
      return parse (sourceStr, pos);
    }

  public void setFormat (int variableNum, Format newFormat)
    {
      elements[variableNum].setFormat = newFormat;
    }

  public void setFormats (Format[] newFormats)
    {
      if (newFormats.length < elements.length)
	throw new IllegalArgumentException ();
      int len = Math.min(newFormats.length, elements.length);
      for (int i = 0; i < len; ++i)
	elements[i].setFormat = newFormats[i];
    }

  public void setLocale (Locale loc)
    {
      locale = loc;
      if (elements != null)
	{
	  for (int i = 0; i < elements.length; ++i)
	    elements[i].setLocale(loc);
	}
    }

  public String toPattern ()
    {
      return pattern;
    }

  // The pattern string.
  private String pattern;
  // The locale.
  private Locale locale;
  // Variables.
  private MessageFormatElement[] elements;
  // Leader text.
  private String leader;
}
