/*
 * Copyright 2005 Frerich Raabe <raabe@kde.org>
 * Copyright (C) 2006, 2013 Apple Inc. 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.
 * 
 * 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.
 */

#include "config.h"
#include "XPathValue.h"

#include "XPathExpressionNode.h"
#include "XPathUtil.h"
#include <limits>
#include <wtf/MathExtras.h>
#include <wtf/NeverDestroyed.h>
#include <wtf/StdLibExtras.h>

namespace WebCore {
namespace XPath {

const NodeSet& Value::toNodeSet() const
{
    if (!isNodeSet())
        Expression::evaluationContext().hadTypeConversionError = true;

    if (!m_data) {
        static NeverDestroyed<NodeSet> emptyNodeSet;
        return emptyNodeSet;
    }

    return m_data->nodeSet;
}    

NodeSet& Value::modifiableNodeSet()
{
    if (!isNodeSet())
        Expression::evaluationContext().hadTypeConversionError = true;

    if (!m_data)
        m_data = Data::create();

    m_type = NodeSetValue;
    return m_data->nodeSet;
}

bool Value::toBoolean() const
{
    switch (m_type) {
        case NodeSetValue:
            return !m_data->nodeSet.isEmpty();
        case BooleanValue:
            return m_bool;
        case NumberValue:
            return m_number && !std::isnan(m_number);
        case StringValue:
            return !m_data->string.isEmpty();
    }
    ASSERT_NOT_REACHED();
    return false;
}

double Value::toNumber() const
{
    switch (m_type) {
        case NodeSetValue:
            return Value(toString()).toNumber();
        case NumberValue:
            return m_number;
        case StringValue: {
            const String& str = m_data->string.simplifyWhiteSpace();

            // String::toDouble() supports exponential notation, which is not allowed in XPath.
            unsigned len = str.length();
            for (unsigned i = 0; i < len; ++i) {
                UChar c = str[i];
                if (!isASCIIDigit(c) && c != '.'  && c != '-')
                    return std::numeric_limits<double>::quiet_NaN();
            }

            bool canConvert;
            double value = str.toDouble(&canConvert);
            if (canConvert)
                return value;
            return std::numeric_limits<double>::quiet_NaN();
        }
        case BooleanValue:
            return m_bool;
    }

    ASSERT_NOT_REACHED();
    return 0.0;
}

String Value::toString() const
{
    switch (m_type) {
        case NodeSetValue:
            if (m_data->nodeSet.isEmpty())
                return emptyString();
            return stringValue(m_data->nodeSet.firstNode());
        case StringValue:
            return m_data->string;
        case NumberValue:
            if (std::isnan(m_number))
                return "NaN"_s;
            if (m_number == 0)
                return "0"_s;
            if (std::isinf(m_number))
                return std::signbit(m_number) ? "-Infinity"_s : "Infinity"_s;
            return String::number(m_number);
        case BooleanValue:
            return m_bool ? "true"_s : "false"_s;
    }

    ASSERT_NOT_REACHED();
    return String();
}

}
}