/*
 * [The "BSD license"]
 *  Copyright (c) 2010 Terence Parr
 *  All rights reserved.
 *
 *  Redistribution and use in source and binary forms, with or without
 *  modification, are permitted provided that the following conditions
 *  are met:
 *  1. Redistributions of source code must retain the above copyright
 *      notice, this list of conditions and the following disclaimer.
 *  2. 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.
 *  3. The name of the author may not be used to endorse or promote products
 *      derived from this software without specific prior written permission.
 *
 *  THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
 */

package org.antlr.tool;

/** Track the names of attributes define in arg lists, return values,
 *  scope blocks etc...
 */
public class Attribute {
	/** The entire declaration such as "String foo;" */
	public String decl;

	/** The type; might be empty such as for Python which has no static typing */
	public String type;

	/** The name of the attribute "foo" */
	public String name;

	/** The optional attribute intialization expression */
	public String initValue;

	public Attribute(String decl) {
		extractAttribute(decl);
	}

	public Attribute(String name, String decl) {
		this.name = name;
		this.decl = decl;
	}

	/** For decls like "String foo" or "char *foo32[3]" compute the ID
	 *  and type declarations.  Also handle "int x=3" and 'T t = new T("foo")'
	 *  but if the separator is ',' you cannot use ',' in the initvalue.
	 *  AttributeScope.addAttributes takes care of the separation so we are
	 *  free here to use from '=' to end of string as the expression.
	 *
	 *  Set name, type, initvalue, and full decl instance vars.
	 */
	protected void extractAttribute(String decl) {
		if ( decl==null ) {
			return;
		}
		boolean inID = false;
		int start = -1;
		int rightEdgeOfDeclarator = decl.length()-1;
		int equalsIndex = decl.indexOf('=');
		if ( equalsIndex>0 ) {
			// everything after the '=' is the init value
			this.initValue = decl.substring(equalsIndex+1,decl.length());
			rightEdgeOfDeclarator = equalsIndex-1;
		}
		// walk backwards looking for start of an ID
		for (int i=rightEdgeOfDeclarator; i>=0; i--) {
			// if we haven't found the end yet, keep going
			if ( !inID && Character.isLetterOrDigit(decl.charAt(i)) ) {
			    inID = true;
			}
			else if ( inID &&
				      !(Character.isLetterOrDigit(decl.charAt(i))||
				       decl.charAt(i)=='_') ) {
				start = i+1;
				break;
			}
		}
		if ( start<0 && inID ) {
			start = 0;
		}
		if ( start<0 ) {
			ErrorManager.error(ErrorManager.MSG_CANNOT_FIND_ATTRIBUTE_NAME_IN_DECL,decl);
		}
		// walk forwards looking for end of an ID
		int stop=-1;
		for (int i=start; i<=rightEdgeOfDeclarator; i++) {
			// if we haven't found the end yet, keep going
			if ( !(Character.isLetterOrDigit(decl.charAt(i))||
				decl.charAt(i)=='_') )
			{
				stop = i;
				break;
			}
			if ( i==rightEdgeOfDeclarator ) {
				stop = i+1;
			}
		}

		// the name is the last ID
		this.name = decl.substring(start,stop);

		// the type is the decl minus the ID (could be empty)
		this.type = decl.substring(0,start);
		if ( stop<=rightEdgeOfDeclarator ) {
			this.type += decl.substring(stop,rightEdgeOfDeclarator+1);
		}
		this.type = type.trim();
		if ( this.type.length()==0 ) {
			this.type = null;
		}

		this.decl = decl;
	}

	public String toString() {
		if ( initValue!=null ) {
			return type+" "+name+"="+initValue;
		}
		return type+" "+name;
	}
}