/*****************************************************************************
 *                                                                           *
 *  This file is part of the BeanShell Java Scripting distribution.          *
 *  Documentation and updates may be found at http://www.beanshell.org/      *
 *                                                                           *
 *  Sun Public License Notice:                                               *
 *                                                                           *
 *  The contents of this file are subject to the Sun Public License Version  *
 *  1.0 (the "License"); you may not use this file except in compliance with *
 *  the License. A copy of the License is available at http://www.sun.com    * 
 *                                                                           *
 *  The Original Code is BeanShell. The Initial Developer of the Original    *
 *  Code is Pat Niemeyer. Portions created by Pat Niemeyer are Copyright     *
 *  (C) 2000.  All Rights Reserved.                                          *
 *                                                                           *
 *  GNU Public License Notice:                                               *
 *                                                                           *
 *  Alternatively, the contents of this file may be used under the terms of  *
 *  the GNU Lesser General Public License (the "LGPL"), in which case the    *
 *  provisions of LGPL are applicable instead of those above. If you wish to *
 *  allow use of your version of this file only under the  terms of the LGPL *
 *  and not to allow others to use your version of this file under the SPL,  *
 *  indicate your decision by deleting the provisions above and replace      *
 *  them with the notice and other provisions required by the LGPL.  If you  *
 *  do not delete the provisions above, a recipient may use your version of  *
 *  this file under either the SPL or the LGPL.                              *
 *                                                                           *
 *  Patrick Niemeyer (pat@pat.net)                                           *
 *  Author of Learning Java, O'Reilly & Associates                           *
 *  http://www.pat.net/~pat/                                                 *
 *                                                                           *
 *****************************************************************************/


package bsh;

import java.util.Hashtable;
import java.lang.reflect.Array;
import java.lang.reflect.InvocationTargetException;

class BSHPrimarySuffix extends SimpleNode
{
	public static final int
		CLASS = 0,
		INDEX = 1,
		NAME = 2,
		PROPERTY = 3;

	public int operation;
	Object index;
	public String field;

	BSHPrimarySuffix(int id) { super(id); }

	/*
		Perform a suffix operation on the given object and return the 
		new value.
		


		obj will be a Node when suffix evaluation begins, allowing us to
		interpret it contextually. (e.g. for .class) Thereafter it will be 
		an value object or LHS (as determined by toLHS).
		

		
		We must handle the toLHS case at each point here.
		

	*/
	public Object doSuffix(
		Object obj, boolean toLHS, 
		CallStack callstack, Interpreter interpreter) 
		throws EvalError
	{
		// Handle ".class" suffix operation
		// Prefix must be a BSHType
		if ( operation == CLASS )
			if ( obj instanceof BSHType ) {
				if ( toLHS )
					throw new EvalError("Can't assign .class", 
						this, callstack );
				NameSpace namespace = callstack.top();
				return ((BSHType)obj).getType( callstack, interpreter );
			} else
				throw new EvalError(
					"Attempt to use .class suffix on non class.", 
					this, callstack );

		/*
			Evaluate our prefix if it needs evaluating first.
			If this is the first evaluation our prefix mayb be a Node 
			(directly from the PrimaryPrefix) - eval() it to an object.  
			If it's an LHS, resolve to a value.

			Note: The ambiguous name construct is now necessary where the node 
			may be an ambiguous name.  If this becomes common we might want to 
			make a static method nodeToObject() or something.  The point is 
			that we can't just eval() - we need to direct the evaluation to 
			the context sensitive type of result; namely object, class, etc.
		*/
		if ( obj instanceof SimpleNode )
			if ( obj instanceof BSHAmbiguousName )
				obj = ((BSHAmbiguousName)obj).toObject(callstack, interpreter);
			else
				obj = ((SimpleNode)obj).eval(callstack, interpreter);	
		else
			if ( obj instanceof LHS )
				try {
					obj = ((LHS)obj).getValue();
				} catch ( UtilEvalError e ) {
					throw e.toEvalError( this, callstack );
				}

		try
		{
			switch(operation)
			{
				case INDEX:
					return doIndex( obj, toLHS, callstack, interpreter );

				case NAME:
					return doName( obj, toLHS, callstack, interpreter );

				case PROPERTY:
					return doProperty( toLHS, obj, callstack, interpreter );

				default:
					throw new InterpreterError( "Unknown suffix type" );
			} 
		}
		catch(ReflectError e)
		{
			throw new EvalError("reflection error: " + e, this, callstack );
		}
		catch(InvocationTargetException e)
		{
			throw new TargetError( "target exception", e.getTargetException(), 
				this, callstack, true);
		}
	}

	/*
		Field access, .length on array, or a method invocation
		Must handle toLHS case for each.
	*/
	private Object doName(
		Object obj, boolean toLHS, 
		CallStack callstack, Interpreter interpreter) 
		throws EvalError, ReflectError, InvocationTargetException
	{
		try {
			// .length on array
			if ( field.equals("length") && obj.getClass().isArray() )
				if ( toLHS )
					throw new EvalError(
						"Can't assign array length", this, callstack );
				else
					return new Primitive(Array.getLength(obj));
			
			// field access
			if ( jjtGetNumChildren() == 0 ) 
				if ( toLHS )
					return Reflect.getLHSObjectField(obj, field);
				else
					return Reflect.getObjectField( obj, field );

			// Method invocation
			// (LHS or non LHS evaluation can both encounter method calls)
			Object[] oa = ((BSHArguments)jjtGetChild(0)).getArguments(
				callstack, interpreter);
			return Reflect.invokeObjectMethod( 
				obj, field, oa, interpreter, callstack, this );

		} catch ( UtilEvalError e ) {
			throw e.toEvalError( this, callstack );
		}
	}

	/**
	*/
	static int getIndexAux(
		Object obj, CallStack callstack, Interpreter interpreter, 
		SimpleNode callerInfo ) 
		throws EvalError
	{
		if ( !obj.getClass().isArray() )
			throw new EvalError("Not an array", callerInfo, callstack );

		int index;
		try {
			Object indexVal = 
				((SimpleNode)callerInfo.jjtGetChild(0)).eval( 
					callstack, interpreter );
			if ( !(indexVal instanceof Primitive) )
				indexVal = Types.getAssignableForm( indexVal, Integer.TYPE);
			index = ((Primitive)indexVal).intValue();
		} catch( UtilEvalError e ) {
			Interpreter.debug("doIndex: "+e);
			throw e.toEvalError( 
				"Arrays may only be indexed by integer types.", 
				callerInfo, callstack );
		}

		return index;
	}

	/**
		array index.
		Must handle toLHS case.
	*/
	private Object doIndex( 
		Object obj, boolean toLHS, 
		CallStack callstack, Interpreter interpreter ) 
		throws EvalError, ReflectError
	{
		int index = getIndexAux( obj, callstack, interpreter, this );
		if ( toLHS )
			return new LHS(obj, index);
		else
			try {
				return Reflect.getIndex(obj, index);
			} catch ( UtilEvalError e ) {
				throw e.toEvalError( this, callstack );
			}
	}

	/**
		Property access.
		Must handle toLHS case.
	*/
	private Object doProperty( boolean toLHS,
		Object obj, CallStack callstack, Interpreter interpreter ) 
		throws EvalError
	{
		if(obj == Primitive.VOID)
			throw new EvalError( 
			"Attempt to access property on undefined variable or class name", 
				this, callstack );

		if ( obj instanceof Primitive )
			throw new EvalError("Attempt to access property on a primitive", 
				this, callstack );

		Object value = ((SimpleNode)jjtGetChild(0)).eval(
			callstack, interpreter);

		if ( !( value instanceof String ) )
			throw new EvalError(
				"Property expression must be a String or identifier.", 
				this, callstack );

		if ( toLHS )
			return new LHS(obj, (String)value);

		// Property style access to Hashtable or Map
		CollectionManager cm = CollectionManager.getCollectionManager();
		if ( cm.isMap( obj ) )
		{
			Object val = cm.getFromMap( obj, value/*key*/ );
			return ( val == null ?  val = Primitive.NULL : val );
		}

		try {
			return Reflect.getObjectProperty( obj, (String)value );
		}
		catch ( UtilEvalError e)  
		{
			throw e.toEvalError( "Property: "+value, this, callstack );
		}
		catch (ReflectError e) 
		{
			throw new EvalError("No such property: " + value, this, callstack );
		}
	}
}