/*

 * (C) 1999-2003 Lars Knoll (knoll@kde.org)

 * Copyright (C) 2004, 2006 Apple Computer, Inc.

 *

 * 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 "MediaList.h"

#include "CSSImportRule.h"

#include "CSSParser.h"

#include "CSSStyleSheet.h"

#include "ExceptionCode.h"

#include "MediaQuery.h"

namespace WebCore {

/* MediaList is used to store 3 types of media related entities which mean the same:

 * Media Queries, Media Types and Media Descriptors.

 * Currently MediaList always tries to parse media queries and if parsing fails,

 * tries to fallback to Media Descriptors if m_fallback flag is set.

 * Slight problem with syntax error handling:

 * CSS 2.1 Spec (http://www.w3.org/TR/CSS21/media.html)

 * specifies that failing media type parsing is a syntax error

 * CSS 3 Media Queries Spec (http://www.w3.org/TR/css3-mediaqueries/)

 * specifies that failing media query is a syntax error

 * HTML 4.01 spec (http://www.w3.org/TR/REC-html40/present/styles.html#adef-media)

 * specifies that Media Descriptors should be parsed with forward-compatible syntax

 * DOM Level 2 Style Sheet spec (http://www.w3.org/TR/DOM-Level-2-Style/)

 * talks about MediaList.mediaText and refers

 *   -  to Media Descriptors of HTML 4.0 in context of StyleSheet

 *   -  to Media Types of CSS 2.0 in context of CSSMediaRule and CSSImportRule

 *

 * These facts create situation where same (illegal) media specification may result in

 * different parses depending on whether it is media attr of style element or part of

 * css @media rule.

 * <style media="screen and resolution > 40dpi"> ..</style> will be enabled on screen devices where as

 * @media screen and resolution > 40dpi {..} will not.

 * This gets more counter-intuitive in JavaScript:

 * document.styleSheets[0].media.mediaText = "screen and resolution > 40dpi" will be ok and

 * enabled, while

 * document.styleSheets[0].cssRules[0].media.mediaText = "screen and resolution > 40dpi" will

 * throw SYNTAX_ERR exception.

 */

MediaList::MediaList(CSSStyleSheet* parentSheet, bool fallbackToDescriptor)

    : StyleBase(parentSheet)

    , m_fallback(fallbackToDescriptor)

{

}

MediaList::MediaList(CSSStyleSheet* parentSheet, const String& media, bool fallbackToDescriptor)

    : StyleBase(parentSheet)

    , m_fallback(fallbackToDescriptor)

{

    ExceptionCode ec = 0;

    setMediaText(media, ec);

    // FIXME: parsing can fail. The problem with failing constructor is that

    // we would need additional flag saying MediaList is not valid

    // Parse can fail only when fallbackToDescriptor == false, i.e when HTML4 media descriptor

    // forward-compatible syntax is not in use. 

    // DOMImplementationCSS seems to mandate that media descriptors are used

    // for both html and svg, even though svg:style doesn't use media descriptors

    // Currently the only places where parsing can fail are

    // creating <svg:style>, creating css media / import rules from js

    if (ec)

        setMediaText("invalid", ec);

}

MediaList::MediaList(CSSImportRule* parentRule, const String& media)

    : StyleBase(parentRule)

    , m_fallback(false)

{

    ExceptionCode ec = 0;

    setMediaText(media, ec);

    if (ec)

        setMediaText("invalid", ec);

}

MediaList::~MediaList()

{

    deleteAllValues(m_queries);

}

static String parseMediaDescriptor(const String& s)

{

    int len = s.length();

    // http://www.w3.org/TR/REC-html40/types.html#type-media-descriptors

    // "Each entry is truncated just before the first character that isn't a

    // US ASCII letter [a-zA-Z] (ISO 10646 hex 41-5a, 61-7a), digit [0-9] (hex 30-39),

    // or hyphen (hex 2d)."

    int i;

    unsigned short c;

    for (i = 0; i < len; ++i) {

        c = s[i];

        if (! ((c >= 'a' && c <= 'z')

            || (c >= 'A' && c <= 'Z')

            || (c >= '1' && c <= '9')

            || (c == '-')))

            break;

    }

    return s.left(i);

}

void MediaList::deleteMedium(const String& oldMedium, ExceptionCode& ec)

{

    RefPtr<MediaList> tempMediaList = MediaList::create();

    CSSParser p(true);

    MediaQuery* oldQuery = 0;

    bool deleteOldQuery = false;

    if (p.parseMediaQuery(tempMediaList.get(), oldMedium)) {

        if (tempMediaList->m_queries.size() > 0)

            oldQuery = tempMediaList->m_queries[0];

    } else if (m_fallback) {

        String medium = parseMediaDescriptor(oldMedium);

        if (!medium.isNull()) {

            oldQuery = new MediaQuery(MediaQuery::None, medium, 0);

            deleteOldQuery = true;

        }

    }

    // DOM Style Sheets spec doesn't allow SYNTAX_ERR to be thrown in deleteMedium

    ec = NOT_FOUND_ERR;

    if (oldQuery) {

        for (size_t i = 0; i < m_queries.size(); ++i) {

            MediaQuery* a = m_queries[i];

            if (*a == *oldQuery) {

                m_queries.remove(i);

                delete a;

                ec = 0;

                break;

            }

        }

        if (deleteOldQuery)

            delete oldQuery;

    }

    if (!ec)

        notifyChanged();

}

String MediaList::mediaText() const

{

    String text("");

    bool first = true;

    for (size_t i = 0; i < m_queries.size(); ++i) {

        if (!first)

            text += ", ";

        else

            first = false;

        text += m_queries[i]->cssText();

    }

    return text;

}

void MediaList::setMediaText(const String& value, ExceptionCode& ec)

{

    RefPtr<MediaList> tempMediaList = MediaList::create();

    CSSParser p(true);

    Vector<String> list;

    value.split(',', list);

    Vector<String>::const_iterator end = list.end();

    for (Vector<String>::const_iterator it = list.begin(); it != end; ++it) {

        String medium = (*it).stripWhiteSpace();

        if (!medium.isEmpty()) {

            if (!p.parseMediaQuery(tempMediaList.get(), medium)) {

                if (m_fallback) {

                    String mediaDescriptor = parseMediaDescriptor(medium);

                    if (!mediaDescriptor.isNull())

                        tempMediaList->m_queries.append(new MediaQuery(MediaQuery::None, mediaDescriptor, 0));

                } else {

                    ec = SYNTAX_ERR;

                    return;

                }

            }          

        } else if (!m_fallback) {

            ec = SYNTAX_ERR;

            return;

        }            

    }

    // ",,,," falls straight through, but is not valid unless fallback

    if (!m_fallback && list.begin() == list.end()) {

        String s = value.stripWhiteSpace();

        if (!s.isEmpty()) {

            ec = SYNTAX_ERR;

            return;

        }

    }

    ec = 0;

    deleteAllValues(m_queries);

    m_queries = tempMediaList->m_queries;

    tempMediaList->m_queries.clear();

    notifyChanged();

}

String MediaList::item(unsigned index) const

{

    if (index < m_queries.size()) {

        MediaQuery* query = m_queries[index];

        return query->cssText();

    }

    return String();

}

void MediaList::appendMedium(const String& newMedium, ExceptionCode& ec)

{

    ec = INVALID_CHARACTER_ERR;

    CSSParser p(true);

    if (p.parseMediaQuery(this, newMedium)) {

        ec = 0;

    } else if (m_fallback) {

        String medium = parseMediaDescriptor(newMedium);

        if (!medium.isNull()) {

            m_queries.append(new MediaQuery(MediaQuery::None, medium, 0));

            ec = 0;

        }

    }

    if (!ec)

        notifyChanged();

}

void MediaList::appendMediaQuery(MediaQuery* mediaQuery)

{

    m_queries.append(mediaQuery);

}

void MediaList::notifyChanged()

{

    for (StyleBase* p = parent(); p; p = p->parent()) {

        if (p->isCSSStyleSheet())

            return static_cast<CSSStyleSheet*>(p)->styleSheetChanged();

    }

}

}