/* -*- Mode: java; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
 *
 * ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (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.mozilla.org/MPL/
 *
 * 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.
 *
 * The Original Code is Rhino code, released
 * May 6, 1999.
 *
 * The Initial Developer of the Original Code is
 * Netscape Communications Corporation.
 * Portions created by the Initial Developer are Copyright (C) 1997-1999
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *   Steve Yegge
 *
 * Alternatively, the contents of this file may be used under the terms of
 * the GNU General Public License Version 2 or later (the "GPL"), in which
 * case the provisions of the GPL are applicable instead of those above. If
 * you wish to allow use of your version of this file only under the terms of
 * the GPL and not to allow others to use your version of this file under the
 * MPL, indicate your decision by deleting the provisions above and replacing
 * them with the notice and other provisions required by the GPL. If you do
 * not delete the provisions above, a recipient may use your version of this
 * file under either the MPL or the GPL.
 *
 * ***** END LICENSE BLOCK ***** */

package org.mozilla.javascript.ast;

import org.mozilla.javascript.Token;

/**
 * AST node representing an infix (binary operator) expression.
 * The operator is the node's {@link Token} type.
 */
public class InfixExpression extends AstNode {

    protected AstNode left;
    protected AstNode right;
    protected int operatorPosition = -1;

    public InfixExpression() {
    }

    public InfixExpression(int pos) {
        super(pos);
    }

    public InfixExpression(int pos, int len) {
        super(pos, len);
    }

    public InfixExpression(int pos, int len,
                           AstNode left,
                           AstNode right) {
        super(pos, len);
        setLeft(left);
        setRight(right);
    }

    /**
     * Constructs a new {@code InfixExpression}.  Updates bounds to include
     * left and right nodes.
     */
    public InfixExpression(AstNode left, AstNode right) {
        setLeftAndRight(left, right);
    }

    /**
     * Constructs a new {@code InfixExpression}.
     * @param operatorPos the <em>absolute</em> position of the operator
     */
    public InfixExpression(int operator, AstNode left,
                           AstNode right, int operatorPos) {
        setType(operator);
        setOperatorPosition(operatorPos - left.getPosition());
        setLeftAndRight(left, right);
    }

    public void setLeftAndRight(AstNode left, AstNode right) {
        assertNotNull(left);
        assertNotNull(right);
        // compute our bounds while children have absolute positions
        int beg = left.getPosition();
        int end = right.getPosition() + right.getLength();
        setBounds(beg, end);
        // this updates their positions to be parent-relative
        setLeft(left);
        setRight(right);
    }

    /**
     * Returns operator token &ndash; alias for {@link #getType}
     */
    public int getOperator() {
        return getType();
    }

    /**
     * Sets operator token &ndash; like {@link #setType}, but throws
     * an exception if the operator is invalid.
     * @throws IllegalArgumentException if operator is not a valid token
     * code
     */
    public void setOperator(int operator) {
        if (!Token.isValidToken(operator))
            throw new IllegalArgumentException("Invalid token: " + operator);
        setType(operator);
    }

    /**
     * Returns the left-hand side of the expression
     */
    public AstNode getLeft() {
        return left;
    }

    /**
     * Sets the left-hand side of the expression, and sets its
     * parent to this node.
     * @param left the left-hand side of the expression
     * @throws IllegalArgumentException} if left is {@code null}
     */
    public void setLeft(AstNode left) {
        assertNotNull(left);
        this.left = left;
        left.setParent(this);
    }

    /**
     * Returns the right-hand side of the expression
     * @return the right-hand side.  It's usually an
     * {@link AstNode} node, but can also be a {@link FunctionNode}
     * representing Function expressions.
     */
    public AstNode getRight() {
        return right;
    }

    /**
     * Sets the right-hand side of the expression, and sets its parent to this
     * node.
     * @throws IllegalArgumentException} if right is {@code null}
     */
    public void setRight(AstNode right) {
        assertNotNull(right);
        this.right = right;
        right.setParent(this);
    }

    /**
     * Returns relative offset of operator token
     */
    public int getOperatorPosition() {
        return operatorPosition;
    }

    /**
     * Sets operator token's relative offset
     * @param operatorPosition offset in parent of operator token
     */
    public void setOperatorPosition(int operatorPosition) {
        this.operatorPosition = operatorPosition;
    }

    @Override
    public boolean hasSideEffects() {
        // the null-checks are for malformed expressions in IDE-mode
        switch (getType()) {
          case Token.COMMA:
              return right != null && right.hasSideEffects();
          case Token.AND:
          case Token.OR:
              return left != null && left.hasSideEffects()
                      || (right != null && right.hasSideEffects());
          default:
              return super.hasSideEffects();
        }
    }

    @Override
    public String toSource(int depth) {
        StringBuilder sb = new StringBuilder();
        sb.append(makeIndent(depth));
        sb.append(left.toSource());
        sb.append(" ");
        sb.append(operatorToString(getType()));
        sb.append(" ");
        sb.append(right.toSource());
        return sb.toString();
    }

    /**
     * Visits this node, the left operand, and the right operand.
     */
    @Override
    public void visit(NodeVisitor v) {
        if (v.visit(this)) {
            left.visit(v);
            right.visit(v);
        }
    }
}
