/* This file is part of the KDE project
 * Copyright (C) 2007, 2008 Fredy Yanardi <fyanardi@gmail.com>
 * Copyright (C) 2007,2009,2010 Thomas Zander <zander@kde.org>
 * Copyright (C) 2010 Christoph Goerlich <chgoerlich@gmx.de>
 * Copyright (C) 2012 Shreya Pandit <shreya@shreyapandit.com>
 *
 * 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 "SpellCheck.h"
#include "BgSpellCheck.h"
#include "SpellCheckMenu.h"
#include "SpellCheckDebug.h"

#include <KoCharacterStyle.h>
#include <KoTextBlockData.h>
#include <KoTextDocumentLayout.h>
#include <KoTextLayoutRootAreaProvider.h>

#include <KSharedConfig>
#include <klocalizedstring.h>
#include <kconfiggroup.h>
#include <ktoggleaction.h>
#include <sonnet/configdialog.h>

#include <QTextBlock>
#include <QThread>
#include <QTimer>
#include <QApplication>
#include <QTextCharFormat>
#include <QAction>

SpellCheck::SpellCheck()
    : m_document(0)
    , m_bgSpellCheck(0)
    , m_enableSpellCheck(true)
    , m_documentIsLoading(false)
    , m_isChecking(false)
    , m_spellCheckMenu(0)
    , m_activeSection(0, 0, 0)
    , m_simpleEdit(false)
    , m_cursorPosition(0)
{
    /* setup actions for this plugin */
    QAction *configureAction = new QAction(i18n("Configure &Spell Checking..."), this);
    connect(configureAction, SIGNAL(triggered()), this, SLOT(configureSpellCheck()));
    addAction("tool_configure_spellcheck", configureAction);

    KToggleAction *spellCheck = new KToggleAction(i18n("Auto Spell Check"), this);
    addAction("tool_auto_spellcheck", spellCheck);

    KConfigGroup spellConfig =  KSharedConfig::openConfig()->group("Spelling");
    m_enableSpellCheck = spellConfig.readEntry("autoSpellCheck", m_enableSpellCheck);
    spellCheck->setChecked(m_enableSpellCheck);
    m_speller = Sonnet::Speller(spellConfig.readEntry("defaultLanguage", "en_US"));
    m_bgSpellCheck = new BgSpellCheck(m_speller, this);

    m_spellCheckMenu = new SpellCheckMenu(m_speller, this);
    QPair<QString, QAction*> pair = m_spellCheckMenu->menuAction();
    addAction(pair.first, pair.second);

    connect(m_bgSpellCheck, SIGNAL(misspelledWord(QString,int,bool)),
            this, SLOT(highlightMisspelled(QString,int,bool)));
    connect(m_bgSpellCheck, SIGNAL(done()), this, SLOT(finishedRun()));
    connect(spellCheck, SIGNAL(toggled(bool)), this, SLOT(setBackgroundSpellChecking(bool)));
}

void SpellCheck::finishedWord(QTextDocument *document, int cursorPosition)
{
    setDocument(document);
    if (!m_enableSpellCheck)
        return;

    QTextBlock block = document->findBlock(cursorPosition);
    if (!block.isValid())
        return;
    KoTextBlockData blockData(block);
    blockData.setMarkupsLayoutValidity(KoTextBlockData::Misspell, false);
    checkSection(document, block.position(), block.position() + block.length() - 1);
}

void SpellCheck::finishedParagraph(QTextDocument *document, int cursorPosition)
{
    setDocument(document);
    Q_UNUSED(document);
    Q_UNUSED(cursorPosition);
}

void SpellCheck::startingSimpleEdit(QTextDocument *document, int cursorPosition)
{
    m_simpleEdit = true;
    setDocument(document);
    m_cursorPosition = cursorPosition;
}

void SpellCheck::checkSection(QTextDocument *document, int startPosition, int endPosition)
{
    if (startPosition >= endPosition) {  // no work
        return;
    }

    foreach (const SpellSections &ss, m_documentsQueue) {
        if (ss.from <= startPosition && ss.to >= endPosition) {
            runQueue();
            m_spellCheckMenu->setVisible(true);
            return;
        }
        // TODO also check if we should replace an existing queued item with a longer span
    }

    SpellSections ss(document, startPosition, endPosition);
    m_documentsQueue.enqueue(ss);
    runQueue();
    m_spellCheckMenu->setVisible(true);
}

void SpellCheck::setDocument(QTextDocument *document)
{
    if (m_document == document)
        return;
    if (m_document)
        disconnect (document, SIGNAL(contentsChange(int,int,int)), this, SLOT(documentChanged(int,int,int)));

    m_document = document;
    connect (document, SIGNAL(contentsChange(int,int,int)), this, SLOT(documentChanged(int,int,int)));
}

QStringList SpellCheck::availableBackends() const
{
    return m_speller.availableBackends();
}

QStringList SpellCheck::availableLanguages() const
{
    return m_speller.availableLanguages();
}

void SpellCheck::setDefaultLanguage(const QString &language)
{
    m_speller.setDefaultLanguage(language);
    m_bgSpellCheck->setDefaultLanguage(language);
    if (m_enableSpellCheck && m_document) {
        checkSection(m_document, 0, m_document->characterCount() - 1);
    }
}

void SpellCheck::setBackgroundSpellChecking(bool on)
{
    if (m_enableSpellCheck == on)
        return;
    KConfigGroup spellConfig =  KSharedConfig::openConfig()->group("Spelling");
    m_enableSpellCheck = on;
    spellConfig.writeEntry("autoSpellCheck", m_enableSpellCheck);
    if (m_document) {
        if (!m_enableSpellCheck) {
            for (QTextBlock block = m_document->begin(); block != m_document->end(); block = block.next()) {
                KoTextBlockData blockData(block);
                blockData.clearMarkups(KoTextBlockData::Misspell);
            }
            m_spellCheckMenu->setEnabled(false);
            m_spellCheckMenu->setVisible(false);
        } else {
            //when re-enabling 'Auto Spell Check' we want spellchecking the whole document
            checkSection(m_document, 0, m_document->characterCount() - 1);
            m_spellCheckMenu->setVisible(true);
        }
    }
}


void SpellCheck::setSkipAllUppercaseWords(bool on)
{
    m_speller.setAttribute(Speller::CheckUppercase, !on);
}

void SpellCheck::setSkipRunTogetherWords(bool on)
{
    m_speller.setAttribute(Speller::SkipRunTogether, on);
}

bool SpellCheck::addWordToPersonal(const QString &word, int startPosition)
{
    QTextBlock block = m_document->findBlock(startPosition);
    if (!block.isValid())
        return false;

    KoTextBlockData blockData(block);
    blockData.setMarkupsLayoutValidity(KoTextBlockData::Misspell, false);
    checkSection(m_document, block.position(), block.position() + block.length() - 1);
    // TODO we should probably recheck the entire document so other occurrences are also removed, but then again we should recheck every document (footer,header etc) not sure how to do this
    return m_bgSpellCheck->addWordToPersonal(word);
}


QString SpellCheck::defaultLanguage() const
{
    return m_speller.defaultLanguage();
}

bool SpellCheck::backgroundSpellChecking()
{
    return m_enableSpellCheck;
}

bool SpellCheck::skipAllUppercaseWords()
{
    return m_speller.testAttribute(Speller::CheckUppercase);
}

bool SpellCheck::skipRunTogetherWords()
{
    return m_speller.testAttribute(Speller::SkipRunTogether);
}

// TODO:
// 1) When editing a misspelled word it should be spellchecked on the fly so the markup is removed when it is OK.
// 2) Deleting a character should be treated as a simple edit
void SpellCheck::highlightMisspelled(const QString &word, int startPosition, bool misspelled)
{
    if (!misspelled)
        return;

#if 0
    // DEBUG
class MyThread : public QThread { public: static void mySleep(unsigned long msecs) { msleep(msecs); }};
static_cast<MyThread*>(QThread::currentThread())->mySleep(400);
#endif

    QTextBlock block = m_activeSection.document->findBlock(startPosition);
    KoTextBlockData blockData(block);
    blockData.appendMarkup(KoTextBlockData::Misspell, startPosition - block.position(), startPosition - block.position() + word.trimmed().length());
}

void SpellCheck::documentChanged(int from, int charsRemoved, int charsAdded)
{
    QTextDocument *document = qobject_cast<QTextDocument*>(sender());
    if (document == 0)
        return;

    // If a simple edit, we use the cursor position to determine where
    // the change occurred. This makes it possible to handle cases
    // where formatting of a block has changed, eg. when dropcaps is used.
    // QTextDocument then reports the change as if the whole block has changed.
    // Ex: Having a 10 char line and you add a char at pos 7:
    // from = block->position()
    // charsRemoved = 10
    // charsAdded = 11
    // m_cursorPosition = 7
    int pos = m_simpleEdit ? m_cursorPosition : from;
    QTextBlock block = document->findBlock(pos);
    if (!block.isValid())
        return;

    do {
        KoTextBlockData blockData(block);
        if (m_enableSpellCheck) {
            // This block and all blocks after this must be relayouted
            blockData.setMarkupsLayoutValidity(KoTextBlockData::Misspell, false);
            // If it's a simple edit we will wait until finishedWord before spellchecking
            // but we need to adjust all markups behind the added/removed character(s)
            if (m_simpleEdit) {
                // Since markups work on positions within each block only the edited block must be rebased
                if (block.position() <= pos) {
                    blockData.rebaseMarkups(KoTextBlockData::Misspell, pos - block.position(), charsAdded - charsRemoved);
                }
            } else {
                // handle not so simple edits (like cut/paste etc)
                checkSection(document, block.position(), block.position() + block.length() - 1);
            }
        } else {
            blockData.clearMarkups(KoTextBlockData::Misspell);
        }
        block = block.next();
    } while(block.isValid() && block.position() <= from + charsAdded);

    m_simpleEdit = false;
}

void SpellCheck::runQueue()
{
    Q_ASSERT(QThread::currentThread() == QApplication::instance()->thread());
    if (m_isChecking)
        return;
    while (!m_documentsQueue.isEmpty()) {
        m_activeSection = m_documentsQueue.dequeue();
        if (m_activeSection.document.isNull())
            continue;
        QTextBlock block = m_activeSection.document->findBlock(m_activeSection.from);
        if (!block.isValid())
            continue;
        m_isChecking = true;
        do {
            KoTextBlockData blockData(block);
            blockData.clearMarkups(KoTextBlockData::Misspell);
            block = block.next();
        } while(block.isValid() && block.position() < m_activeSection.to);

        m_bgSpellCheck->startRun(m_activeSection.document, m_activeSection.from, m_activeSection.to);
        break;
    }
}

void SpellCheck::configureSpellCheck()
{
    Sonnet::ConfigDialog *dialog = new Sonnet::ConfigDialog(0);
    connect (dialog, SIGNAL(languageChanged(QString)), this, SLOT(setDefaultLanguage(QString)));
    dialog->exec();
    delete dialog;
}

void SpellCheck::finishedRun()
{
    Q_ASSERT(QThread::currentThread() == QApplication::instance()->thread());
    m_isChecking = false;

    KoTextDocumentLayout *lay = qobject_cast<KoTextDocumentLayout*>(m_activeSection.document->documentLayout());
    lay->provider()->updateAll();

    QTimer::singleShot(0, this, SLOT(runQueue()));
}

void SpellCheck::setCurrentCursorPosition(QTextDocument *document, int cursorPosition)
{
    setDocument(document);
    if (m_enableSpellCheck) {
        //check if word at cursor is misspelled
        QTextBlock block = m_document->findBlock(cursorPosition);
        if (block.isValid()) {
            KoTextBlockData blockData(block);
            KoTextBlockData::MarkupRange range = blockData.findMarkup(KoTextBlockData::Misspell, cursorPosition - block.position());
            if (int length = range.lastChar - range.firstChar) {
                QString word = block.text().mid(range.firstChar, length);
                m_spellCheckMenu->setMisspelled(word, block.position() + range.firstChar, length);
                QString language = m_bgSpellCheck->currentLanguage();
                if (!m_bgSpellCheck->currentLanguage().isEmpty() && !m_bgSpellCheck->currentCountry().isEmpty()) {
                    language += '_';
                }
                language += m_bgSpellCheck->currentCountry();
                m_spellCheckMenu->setCurrentLanguage(language);
                m_spellCheckMenu->setVisible(true);
                m_spellCheckMenu->setEnabled(true);
                return;
            }
            m_spellCheckMenu->setEnabled(false);
        } else {
            m_spellCheckMenu->setEnabled(false);
        }
    }
}

void SpellCheck::replaceWordBySuggestion(const QString &word, int startPosition, int lengthOfWord)
{
    if (!m_document)
        return;

    QTextBlock block = m_document->findBlock(startPosition);
    if (!block.isValid())
        return;

    QTextCursor cursor(m_document);
    cursor.setPosition(startPosition);
    cursor.movePosition(QTextCursor::NextCharacter,QTextCursor::KeepAnchor, lengthOfWord);
    cursor.removeSelectedText();
    cursor.insertText(word);
}