/*
 * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
 *           (C) 1999 Antti Koivisto (koivisto@kde.org)
 *           (C) 2001 Dirk Mueller ( mueller@kde.org )
 * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008 Apple Inc. All rights reserved.
 * Copyright (C) 2006 Andrew Wellington (proton@wiretapped.net)
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public License
 * along with this library; see the file COPYING.LIB.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA 02110-1301, USA.
 *
 */

#include "config.h"
#include "Length.h"

#include "CalculationValue.h"
#include <wtf/ASCIICType.h>
#include <wtf/Assertions.h>
#include <wtf/StdLibExtras.h>
#include <wtf/text/StringBuffer.h>
#include <wtf/text/WTFString.h>

using namespace WTF;

namespace WebCore {

static Length parseLength(const UChar* data, unsigned length)
{
    if (length == 0)
        return Length(1, Relative);

    unsigned i = 0;
    while (i < length && isSpaceOrNewline(data[i]))
        ++i;
    if (i < length && (data[i] == '+' || data[i] == '-'))
        ++i;
    while (i < length && isASCIIDigit(data[i]))
        ++i;
    unsigned intLength = i;
    while (i < length && (isASCIIDigit(data[i]) || data[i] == '.'))
        ++i;
    unsigned doubleLength = i;

    // IE quirk: Skip whitespace between the number and the % character (20 % => 20%).
    while (i < length && isSpaceOrNewline(data[i]))
        ++i;

    bool ok;
    UChar next = (i < length) ? data[i] : ' ';
    if (next == '%') {
        // IE quirk: accept decimal fractions for percentages.
        double r = charactersToDouble(data, doubleLength, &ok);
        if (ok)
            return Length(r, Percent);
        return Length(1, Relative);
    }
    int r = charactersToIntStrict(data, intLength, &ok);
    if (next == '*') {
        if (ok)
            return Length(r, Relative);
        return Length(1, Relative);
    }
    if (ok)
        return Length(r, Fixed);
    return Length(0, Relative);
}

static int countCharacter(const UChar* data, unsigned length, UChar character)
{
    int count = 0;
    for (int i = 0; i < static_cast<int>(length); ++i)
        count += data[i] == character;
    return count;
}

std::unique_ptr<Length[]> newCoordsArray(const String& string, int& len)
{
    unsigned length = string.length();
    const UChar* data = string.characters();
    StringBuffer<UChar> spacified(length);
    for (unsigned i = 0; i < length; i++) {
        UChar cc = data[i];
        if (cc > '9' || (cc < '0' && cc != '-' && cc != '*' && cc != '.'))
            spacified[i] = ' ';
        else
            spacified[i] = cc;
    }
    RefPtr<StringImpl> str = StringImpl::adopt(spacified);

    str = str->simplifyWhiteSpace();

    len = countCharacter(str->characters(), str->length(), ' ') + 1;
    auto r = std::make_unique<Length[]>(len);

    int i = 0;
    unsigned pos = 0;
    size_t pos2;

    while ((pos2 = str->find(' ', pos)) != notFound) {
        r[i++] = parseLength(str->characters() + pos, pos2 - pos);
        pos = pos2+1;
    }
    r[i] = parseLength(str->characters() + pos, str->length() - pos);

    ASSERT(i == len - 1);

    return r;
}

std::unique_ptr<Length[]> newLengthArray(const String& string, int& len)
{
    RefPtr<StringImpl> str = string.impl()->simplifyWhiteSpace();
    if (!str->length()) {
        len = 1;
        return nullptr;
    }

    len = countCharacter(str->characters(), str->length(), ',') + 1;
    auto r = std::make_unique<Length[]>(len);

    int i = 0;
    unsigned pos = 0;
    size_t pos2;

    while ((pos2 = str->find(',', pos)) != notFound) {
        r[i++] = parseLength(str->characters() + pos, pos2 - pos);
        pos = pos2+1;
    }

    ASSERT(i == len - 1);

    // IE Quirk: If the last comma is the last char skip it and reduce len by one.
    if (str->length()-pos > 0)
        r[i] = parseLength(str->characters() + pos, str->length() - pos);
    else
        len--;

    return r;
}
        
class CalculationValueHandleMap {
    WTF_MAKE_FAST_ALLOCATED;
public:
    CalculationValueHandleMap() 
        : m_index(1) 
    {
    }
    
    int insert(PassRefPtr<CalculationValue> calcValue)
    {
        ASSERT(m_index);
        // FIXME calc(): https://bugs.webkit.org/show_bug.cgi?id=80489
        // This monotonically increasing handle generation scheme is potentially wasteful
        // of the handle space. Consider reusing empty handles.
        while (m_map.contains(m_index))
            m_index++;
        
        m_map.set(m_index, calcValue);       
        
        return m_index;
    }

    void remove(int index)
    {
        ASSERT(m_map.contains(index));
        m_map.remove(index);
    }

    void remove(HashMap<int, RefPtr<CalculationValue>>::iterator it)
    {
        ASSERT(it != m_map.end());
        m_map.remove(it);
    }

    PassRefPtr<CalculationValue> get(int index)
    {
        ASSERT(m_map.contains(index));
        return m_map.get(index);
    }

    HashMap<int, RefPtr<CalculationValue>>::iterator find(int index)
    {
        ASSERT(m_map.contains(index));
        return m_map.find(index);
    }

private:        
    int m_index;
    HashMap<int, RefPtr<CalculationValue>> m_map;
};
    
static CalculationValueHandleMap& calcHandles()
{
    DEFINE_STATIC_LOCAL(CalculationValueHandleMap, handleMap, ());
    return handleMap;
}

Length::Length(PassRefPtr<CalculationValue> calc)
    : m_quirk(false)
    , m_type(Calculated)
    , m_isFloat(false)
{
    m_intValue = calcHandles().insert(calc);
}
        
Length Length::blendMixedTypes(const Length& from, double progress) const
{
    if (progress <= 0.0)
        return from;
        
    if (progress >= 1.0)
        return *this;
        
    OwnPtr<CalcExpressionNode> blend = adoptPtr(new CalcExpressionBlendLength(from, *this, progress));
    return Length(CalculationValue::create(blend.release(), CalculationRangeAll));
}
          
PassRefPtr<CalculationValue> Length::calculationValue() const
{
    ASSERT(isCalculated());
    return calcHandles().get(calculationHandle());
}
    
void Length::incrementCalculatedRef() const
{
    ASSERT(isCalculated());
    calculationValue()->ref();
}

void Length::decrementCalculatedRef() const
{
    ASSERT(isCalculated());
    auto it = calcHandles().find(calculationHandle());
    if (it->value->hasOneRef())
        calcHandles().remove(it);
}

float Length::nonNanCalculatedValue(int maxValue) const
{
    ASSERT(isCalculated());
    float result = calculationValue()->evaluate(maxValue);
    if (std::isnan(result))
        return 0;
    return result;
}

bool Length::isCalculatedEqual(const Length& o) const
{
    return isCalculated() && (calculationValue() == o.calculationValue() || *calculationValue() == *o.calculationValue());
}

struct SameSizeAsLength {
    int32_t value;
    int32_t metaData;
};
COMPILE_ASSERT(sizeof(Length) == sizeof(SameSizeAsLength), length_should_stay_small);

} // namespace WebCore