/*
 * Copyright (C) 2010 Google 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 APPLE INC. AND ITS CONTRIBUTORS ``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 APPLE INC. OR ITS CONTRIBUTORS 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 "sky/engine/core/dom/DOMTokenList.h"

#include "sky/engine/bindings/exception_state.h"
#include "sky/engine/core/dom/Document.h"
#include "sky/engine/core/dom/Element.h"
#include "sky/engine/core/dom/ExceptionCode.h"
#include "sky/engine/core/dom/SpaceSplitString.h"
#include "sky/engine/core/html/parser/HTMLParserIdioms.h"
#include "sky/engine/wtf/text/StringBuilder.h"

namespace blink {

DOMTokenList::DOMTokenList(Element& element)
    : m_element(&element)
{
}

void DOMTokenList::ref()
{
    m_element->ref();
}

void DOMTokenList::deref()
{
    m_element->deref();
}

unsigned DOMTokenList::length() const
{
    return m_element->hasClass() ? classNames().size() : 0;
}

const AtomicString DOMTokenList::item(unsigned index) const
{
    if (index >= length())
        return AtomicString();
    return classNames()[index];
}

bool DOMTokenList::containsInternal(const AtomicString& token) const
{
    return m_element->hasClass() && classNames().contains(token);
}

const SpaceSplitString& DOMTokenList::classNames() const
{
    ASSERT(m_element->hasClass());
    return m_element->classNames();
}

const AtomicString& DOMTokenList::value() const
{
    return m_element->getAttribute(HTMLNames::classAttr);
}

void DOMTokenList::setValue(const AtomicString& value)
{
    m_element->setAttribute(HTMLNames::classAttr, value);
}

void DOMTokenList::clear()
{
    m_element->removeAttribute(HTMLNames::classAttr);
}

bool DOMTokenList::validateToken(const String& token, ExceptionState& exceptionState)
{
    if (token.isEmpty()) {
        exceptionState.ThrowDOMException(SyntaxError, "The token provided must not be empty.");
        return false;
    }

    if (token.find(isHTMLSpace) != kNotFound) {
        exceptionState.ThrowDOMException(InvalidCharacterError, "The token provided ('" + token + "') contains HTML space characters, which are not valid in tokens.");
        return false;
    }

    return true;
}

bool DOMTokenList::validateTokens(const Vector<String>& tokens, ExceptionState& exceptionState)
{
    for (size_t i = 0; i < tokens.size(); ++i) {
        if (!validateToken(tokens[i], exceptionState))
            return false;
    }

    return true;
}

bool DOMTokenList::contains(const AtomicString& token, ExceptionState& exceptionState) const
{
    if (!validateToken(token, exceptionState))
        return false;
    return containsInternal(token);
}

void DOMTokenList::add(const AtomicString& token, ExceptionState& exceptionState)
{
    Vector<String> tokens;
    tokens.append(token.string());
    add(tokens, exceptionState);
}

// Optimally, this should take a Vector<AtomicString> const ref in argument but the
// bindings generator does not handle that.
void DOMTokenList::add(const Vector<String>& tokens, ExceptionState& exceptionState)
{
    Vector<String> filteredTokens;
    filteredTokens.reserveCapacity(tokens.size());
    for (size_t i = 0; i < tokens.size(); ++i) {
        if (!validateToken(tokens[i], exceptionState))
            return;
        if (containsInternal(AtomicString(tokens[i])))
            continue;
        if (filteredTokens.contains(tokens[i]))
            continue;
        filteredTokens.append(tokens[i]);
    }

    if (filteredTokens.isEmpty())
        return;

    setValue(addTokens(value(), filteredTokens));
}

void DOMTokenList::remove(const AtomicString& token, ExceptionState& exceptionState)
{
    Vector<String> tokens;
    tokens.append(token.string());
    remove(tokens, exceptionState);
}

// Optimally, this should take a Vector<AtomicString> const ref in argument but the
// bindings generator does not handle that.
void DOMTokenList::remove(const Vector<String>& tokens, ExceptionState& exceptionState)
{
    if (!validateTokens(tokens, exceptionState))
        return;

    // Check using containsInternal first since it is a lot faster than going
    // through the string character by character.
    bool found = false;
    for (size_t i = 0; i < tokens.size(); ++i) {
        if (containsInternal(AtomicString(tokens[i]))) {
            found = true;
            break;
        }
    }

    if (found)
        setValue(removeTokens(value(), tokens));
}

bool DOMTokenList::toggle(const AtomicString& token, ExceptionState& exceptionState)
{
    if (!validateToken(token, exceptionState))
        return false;

    if (containsInternal(token)) {
        removeInternal(token);
        return false;
    }
    addInternal(token);
    return true;
}

bool DOMTokenList::toggle(const AtomicString& token, bool force, ExceptionState& exceptionState)
{
    if (!validateToken(token, exceptionState))
        return false;

    if (force)
        addInternal(token);
    else
        removeInternal(token);

    return force;
}

void DOMTokenList::addInternal(const AtomicString& token)
{
    if (!containsInternal(token))
        setValue(addToken(value(), token));
}

void DOMTokenList::removeInternal(const AtomicString& token)
{
    // Check using contains first since it uses AtomicString comparisons instead
    // of character by character testing.
    if (!containsInternal(token))
        return;
    setValue(removeToken(value(), token));
}

AtomicString DOMTokenList::addToken(const AtomicString& input, const AtomicString& token)
{
    Vector<String> tokens;
    tokens.append(token.string());
    return addTokens(input, tokens);
}

// This returns an AtomicString because it is always passed as argument to setValue() and setValue()
// takes an AtomicString in argument.
AtomicString DOMTokenList::addTokens(const AtomicString& input, const Vector<String>& tokens)
{
    bool needsSpace = false;

    StringBuilder builder;
    if (!input.isEmpty()) {
        builder.append(input);
        needsSpace = !isHTMLSpace<UChar>(input[input.length() - 1]);
    }

    for (size_t i = 0; i < tokens.size(); ++i) {
        if (needsSpace)
            builder.append(' ');
        builder.append(tokens[i]);
        needsSpace = true;
    }

    return builder.toAtomicString();
}

AtomicString DOMTokenList::removeToken(const AtomicString& input, const AtomicString& token)
{
    Vector<String> tokens;
    tokens.append(token.string());
    return removeTokens(input, tokens);
}

// This returns an AtomicString because it is always passed as argument to setValue() and setValue()
// takes an AtomicString in argument.
AtomicString DOMTokenList::removeTokens(const AtomicString& input, const Vector<String>& tokens)
{
    // Algorithm defined at http://www.whatwg.org/specs/web-apps/current-work/multipage/common-microsyntaxes.html#remove-a-token-from-a-string
    // New spec is at http://dom.spec.whatwg.org/#remove-a-token-from-a-string

    unsigned inputLength = input.length();
    StringBuilder output; // 3
    output.reserveCapacity(inputLength);
    unsigned position = 0; // 4

    // Step 5
    while (position < inputLength) {
        if (isHTMLSpace<UChar>(input[position])) { // 6
            output.append(input[position++]); // 6.1, 6.2
            continue; // 6.3
        }

        // Step 7
        StringBuilder tokenBuilder;
        while (position < inputLength && isNotHTMLSpace<UChar>(input[position]))
            tokenBuilder.append(input[position++]);

        // Step 8
        String token = tokenBuilder.toString();
        if (tokens.contains(token)) {
            // Step 8.1
            while (position < inputLength && isHTMLSpace<UChar>(input[position]))
                ++position;

            // Step 8.2
            size_t j = output.length();
            while (j > 0 && isHTMLSpace<UChar>(output[j - 1]))
                --j;
            output.resize(j);

            // Step 8.3
            if (position < inputLength && !output.isEmpty())
                output.append(' ');
        } else {
            output.append(token); // Step 9
        }
    }

    return output.toAtomicString();
}

} // namespace blink