/*
 ***** BEGIN LICENSE BLOCK *****
 * Version: EPL 1.0/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Eclipse Public
 * License Version 1.0 (the "License"); you may not use this file
 * except in compliance with the License. You may obtain a copy of
 * the License at http://www.eclipse.org/legal/epl-v10.html
 *
 * Software distributed under the License is distributed on an "AS
 * IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
 * implied. See the License for the specific language governing
 * rights and limitations under the License.
 *
 * Copyright (C) 2001-2002 Jan Arne Petersen <jpetersen@uni-bonn.de>
 * Copyright (C) 2001-2002 Benoit Cerrina <b.cerrina@wanadoo.fr>
 * Copyright (C) 2002-2004 Anders Bengtsson <ndrsbngtssn@yahoo.se>
 * Copyright (C) 2004 Thomas E Enebo <enebo@acm.org>
 * 
 * Alternatively, the contents of this file may be used under the terms of
 * either of the GNU General Public License Version 2 or later (the "GPL"),
 * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
 * under the terms of either the GPL or the LGPL, and not to allow others to
 * use your version of this file under the terms of the EPL, indicate your
 * decision by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL or the LGPL. If you do not delete
 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the EPL, the GPL or the LGPL.
 ***** END LICENSE BLOCK *****/
package org.jruby.ast;

import java.util.List;

import org.jruby.Ruby;
import org.jruby.RubyLocalJumpError;
import org.jruby.ast.visitor.NodeVisitor;
import org.jruby.evaluator.ASTInterpreter;
import org.jruby.exceptions.JumpException;
import org.jruby.exceptions.RaiseException;
import org.jruby.javasupport.util.RuntimeHelpers;
import org.jruby.lexer.yacc.ISourcePosition;
import org.jruby.runtime.Block;
import org.jruby.runtime.ThreadContext;
import org.jruby.runtime.builtin.IRubyObject;

/** 
 * Represents a while statement. This could be the both versions:
 * 
 * while &lt;condition&gt;
 *    &lt;body&gt;
 * end
 * 
 * and
 * 
 * &lt;body&gt; 'while' &lt;condition&gt;
 */
public class WhileNode extends Node {
    private final Node conditionNode;
    private final Node bodyNode;
    private final boolean evaluateAtStart;
    
    public boolean containsNonlocalFlow = false;

    public WhileNode(ISourcePosition position, Node conditionNode, Node bodyNode) {
        this(position, conditionNode, bodyNode, true);
    }

    public WhileNode(ISourcePosition position, Node conditionNode, Node bodyNode,
            boolean evalAtStart) {
        super(position);
        
        assert conditionNode != null : "conditionNode is not null";
        assert bodyNode != null : "bodyNode is not null";
        
        this.conditionNode = conditionNode;
        this.bodyNode = bodyNode;
        this.evaluateAtStart = evalAtStart;
    }

    public NodeType getNodeType() {
        return NodeType.WHILENODE;
    }
    
    /**
     * Accept for the visitor pattern.
     * @param iVisitor the visitor
     **/
    public Object accept(NodeVisitor iVisitor) {
        return iVisitor.visitWhileNode(this);
    }
    
    /**
     * Gets the bodyNode.
     * @return Returns a Node
     */
    public Node getBodyNode() {
        return bodyNode;
    }

    /**
     * Gets the conditionNode.
     * @return Returns a Node
     */
    public Node getConditionNode() {
        return conditionNode;
    }
    
    /**
     * Determine whether this is while or do while
     * @return true if you are a while, false if do while
     */
    public boolean evaluateAtStart() {
        return evaluateAtStart;
    }

    public List<Node> childNodes() {
        return Node.createList(conditionNode, bodyNode);
    }

    @Override
    public IRubyObject interpret(Ruby runtime, ThreadContext context, IRubyObject self, Block aBlock) {
        IRubyObject result = null;
        boolean firstTest = evaluateAtStart;
        
        outerLoop: while (!firstTest || conditionNode.interpret(runtime,context,self, aBlock).isTrue()) {
            firstTest = true;
            loop: while (true) { // Used for the 'redo' command
                try {
                    bodyNode.interpret(runtime,context, self, aBlock);
                    break loop;
                } catch (RaiseException re) {
                    if (runtime.getLocalJumpError().isInstance(re.getException())) {
                        RubyLocalJumpError jumpError = (RubyLocalJumpError)re.getException();
                        
                        IRubyObject reason = jumpError.reason();
                        
                        // admittedly inefficient
                        if (reason.asJavaString().equals("break")) {
                            return jumpError.exit_value();
                        } else if (reason.asJavaString().equals("next")) {
                            break loop;
                        } else if (reason.asJavaString().equals("redo")) {
                            continue;
                        }
                    }
                    
                    throw re;
                } catch (JumpException.RedoJump rj) {
                    continue;
                } catch (JumpException.NextJump nj) {
                    break loop;
                } catch (JumpException.BreakJump bj) {
                    // JRUBY-530, while case
                    result = RuntimeHelpers.breakJumpInWhile(bj, context);
                    break outerLoop;
                }
            }
        }
        if (result == null) {
            result = runtime.getNil();
        }
        return ASTInterpreter.pollAndReturn(context, result);
    }
}
