/* -*- Mode: java; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

package org.mozilla.javascript.ast;

import org.mozilla.javascript.Token;

/**
 * AST node for let statements and expressions.
 * Node type is {@link Token#LET} or {@link Token#LETEXPR}.<p>
 *
 * <pre> <i>LetStatement</i>:
 *     <b>let</b> ( VariableDeclarationList ) Block
 * <i>LetExpression</i>:
 *     <b>let</b> ( VariableDeclarationList ) Expression</pre>
 *
 * Note that standalone let-statements with no parens or body block,
 * such as {@code let x=6, y=7;}, are represented as a
 * {@link VariableDeclaration} node of type {@code Token.LET},
 * wrapped with an {@link ExpressionStatement}.<p>
 */
public class LetNode extends Scope {

    private VariableDeclaration variables;
    private AstNode body;
    private int lp = -1;
    private int rp = -1;

    {
        type = Token.LETEXPR;
    }

    public LetNode() {
    }

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

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

    /**
     * Returns variable list
     */
    public VariableDeclaration getVariables() {
        return variables;
    }

    /**
     * Sets variable list.  Sets list parent to this node.
     * @throws IllegalArgumentException if variables is {@code null}
     */
    public void setVariables(VariableDeclaration variables) {
        assertNotNull(variables);
        this.variables = variables;
        variables.setParent(this);
    }

    /**
     * Returns body statement or expression.  Body is {@code null} if the
     * form of the let statement is similar to a VariableDeclaration, with no
     * curly-brace.  (This form is used to define let-bound variables in the
     * scope of the current block.)<p>
     *
     * @return the body form
     */
    public AstNode getBody() {
        return body;
    }

    /**
     * Sets body statement or expression.  Also sets the body parent to this
     * node.
     * @param body the body statement or expression.  May be
     * {@code null}.
     */
    public void setBody(AstNode body) {
        this.body = body;
        if (body != null)
            body.setParent(this);
    }

    /**
     * Returns left paren position, -1 if missing
     */
    public int getLp() {
        return lp;
    }

    /**
     * Sets left paren position
     */
    public void setLp(int lp) {
        this.lp = lp;
    }

    /**
     * Returns right paren position, -1 if missing
     */
    public int getRp() {
        return rp;
    }

    /**
     * Sets right paren position
     */
    public void setRp(int rp) {
        this.rp = rp;
    }

    /**
     * Sets both paren positions
     */
    public void setParens(int lp, int rp) {
        this.lp = lp;
        this.rp = rp;
    }

    @Override
    public String toSource(int depth) {
        String pad = makeIndent(depth);
        StringBuilder sb = new StringBuilder();
        sb.append(pad);
        sb.append("let (");
        printList(variables.getVariables(), sb);
        sb.append(") ");
        if (body != null) {
            sb.append(body.toSource(depth));
        }
        return sb.toString();
    }

    /**
     * Visits this node, the variable list, and if present, the body
     * expression or statement.
     */
    @Override
    public void visit(NodeVisitor v) {
        if (v.visit(this)) {
            variables.visit(v);
            if (body != null) {
                body.visit(v);
            }
        }
    }
}