/****************************************************************************
**
** Copyright (C) 2012 Nokia Corporation and/or its subsidiary(-ies).
** All rights reserved.
** Contact: Nokia Corporation (qt-info@nokia.com)
**
** This file is part of the QtCore module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** GNU Lesser General Public License Usage
** This file may be used under the terms of the GNU Lesser General Public
** License version 2.1 as published by the Free Software Foundation and
** appearing in the file LICENSE.LGPL included in the packaging of this
** file. Please review the following information to ensure the GNU Lesser
** General Public License version 2.1 requirements will be met:
** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** In addition, as a special exception, Nokia gives you certain additional
** rights. These rights are described in the Nokia Qt LGPL Exception
** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU General
** Public License version 3.0 as published by the Free Software Foundation
** and appearing in the file LICENSE.GPL included in the packaging of this
** file. Please review the following information to ensure the GNU General
** Public License version 3.0 requirements will be met:
** http://www.gnu.org/copyleft/gpl.html.
**
** Other Usage
** Alternatively, this file may be used in accordance with the terms and
** conditions contained in a signed written agreement between you and Nokia.
**
**
**
**
**
** $QT_END_LICENSE$
**
****************************************************************************/

#include "qfilesystemwatcher.h"
#include "qfilesystemwatcher_win_p.h"

#ifndef QT_NO_FILESYSTEMWATCHER

#include <qdebug.h>
#include <qfileinfo.h>
#include <qstringlist.h>
#include <qset.h>
#include <qdatetime.h>
#include <qdir.h>

QT_BEGIN_NAMESPACE

QWindowsFileSystemWatcherEngine::~QWindowsFileSystemWatcherEngine()
{
    foreach(QWindowsFileSystemWatcherEngineThread *thread, threads) {
        thread->stop();
        thread->wait();
        delete thread;
    }
}

QStringList QWindowsFileSystemWatcherEngine::addPaths(const QStringList &paths,
                                                       QStringList *files,
                                                       QStringList *directories)
{
    // qDebug()<<"Adding"<<paths.count()<<"to existing"<<(files->count() + directories->count())<<"watchers";
    QStringList p = paths;
    QMutableListIterator<QString> it(p);
    while (it.hasNext()) {
        QString path = it.next();
        QString normalPath = path;
        if ((normalPath.endsWith(QLatin1Char('/')) && !normalPath.endsWith(QLatin1String(":/")))
            || (normalPath.endsWith(QLatin1Char('\\')) && !normalPath.endsWith(QLatin1String(":\\")))
#ifdef Q_OS_WINCE
            && normalPath.size() > 1)
#else
            )
#endif
        normalPath.chop(1);
        QFileInfo fileInfo(normalPath.toLower());
        if (!fileInfo.exists())
            continue;

        bool isDir = fileInfo.isDir();
        if (isDir) {
            if (directories->contains(path))
                continue;
        } else {
            if (files->contains(path))
                continue;
        }

        // qDebug()<<"Looking for a thread/handle for"<<normalPath;

        const QString absolutePath = isDir ? fileInfo.absoluteFilePath() : fileInfo.absolutePath();
        const uint flags = isDir
                           ? (FILE_NOTIFY_CHANGE_DIR_NAME
                              | FILE_NOTIFY_CHANGE_FILE_NAME)
                           : (FILE_NOTIFY_CHANGE_DIR_NAME
                              | FILE_NOTIFY_CHANGE_FILE_NAME
                              | FILE_NOTIFY_CHANGE_ATTRIBUTES
                              | FILE_NOTIFY_CHANGE_SIZE
                              | FILE_NOTIFY_CHANGE_LAST_WRITE
                              | FILE_NOTIFY_CHANGE_SECURITY);

        QWindowsFileSystemWatcherEngine::PathInfo pathInfo;
        pathInfo.absolutePath = absolutePath;
        pathInfo.isDir = isDir;
        pathInfo.path = path;
        pathInfo = fileInfo;

        // Look for a thread
        QWindowsFileSystemWatcherEngineThread *thread = 0;
        QWindowsFileSystemWatcherEngine::Handle handle;
        QList<QWindowsFileSystemWatcherEngineThread *>::const_iterator jt, end;
        end = threads.constEnd();
        for(jt = threads.constBegin(); jt != end; ++jt) {
            thread = *jt;
            QMutexLocker locker(&(thread->mutex));

            handle = thread->handleForDir.value(absolutePath);
            if (handle.handle != INVALID_HANDLE_VALUE && handle.flags == flags) {
                // found a thread now insert...
                // qDebug()<<"  Found a thread"<<thread;

                QHash<QString, QWindowsFileSystemWatcherEngine::PathInfo> &h
                        = thread->pathInfoForHandle[handle.handle];
                if (!h.contains(fileInfo.absoluteFilePath())) {
                    thread->pathInfoForHandle[handle.handle].insert(fileInfo.absoluteFilePath(), pathInfo);
                    if (isDir)
                        directories->append(path);
                    else
                        files->append(path);
                }
                it.remove();
                thread->wakeup();
                break;
            }
        }

        // no thread found, first create a handle
        if (handle.handle == INVALID_HANDLE_VALUE || handle.flags != flags) {
            // qDebug()<<"  No thread found";
            // Volume and folder paths need a trailing slash for proper notification
            // (e.g. "c:" -> "c:/").
            const QString effectiveAbsolutePath =
                    isDir ? (absolutePath + QLatin1Char('/')) : absolutePath;

            handle.handle = FindFirstChangeNotification((wchar_t*) QDir::toNativeSeparators(effectiveAbsolutePath).utf16(), false, flags);
            handle.flags = flags;
            if (handle.handle == INVALID_HANDLE_VALUE)
                continue;

            // now look for a thread to insert
            bool found = false;
            foreach(QWindowsFileSystemWatcherEngineThread *thread, threads) {
                QMutexLocker(&(thread->mutex));
                if (thread->handles.count() < MAXIMUM_WAIT_OBJECTS) {
                    // qDebug() << "  Added handle" << handle.handle << "for" << absolutePath << "to watch" << fileInfo.absoluteFilePath();
                    // qDebug()<< "  to existing thread"<<thread;
                    thread->handles.append(handle.handle);
                    thread->handleForDir.insert(absolutePath, handle);

                    thread->pathInfoForHandle[handle.handle].insert(fileInfo.absoluteFilePath(), pathInfo);
                    if (isDir)
                        directories->append(path);
                    else
                        files->append(path);

                    it.remove();
                    found = true;
                    thread->wakeup();
                    break;
                }
            }
            if (!found) {
                QWindowsFileSystemWatcherEngineThread *thread = new QWindowsFileSystemWatcherEngineThread();
                //qDebug()<<"  ###Creating new thread"<<thread<<"("<<(threads.count()+1)<<"threads)";
                thread->handles.append(handle.handle);
                thread->handleForDir.insert(absolutePath, handle);

                thread->pathInfoForHandle[handle.handle].insert(fileInfo.absoluteFilePath(), pathInfo);
                if (isDir)
                    directories->append(path);
                else
                    files->append(path);

                connect(thread, SIGNAL(fileChanged(QString,bool)),
                        this, SIGNAL(fileChanged(QString,bool)));
                connect(thread, SIGNAL(directoryChanged(QString,bool)),
                        this, SIGNAL(directoryChanged(QString,bool)));
                
                thread->msg = '@';
                thread->start();
                threads.append(thread);
                it.remove();
            }
        }
    }
    return p;
}

QStringList QWindowsFileSystemWatcherEngine::removePaths(const QStringList &paths,
                                                          QStringList *files,
                                                          QStringList *directories)
{
    // qDebug()<<"removePaths"<<paths;
    QStringList p = paths;
    QMutableListIterator<QString> it(p);
    while (it.hasNext()) {
        QString path = it.next();
        QString normalPath = path;
        if (normalPath.endsWith(QLatin1Char('/')) || normalPath.endsWith(QLatin1Char('\\')))
            normalPath.chop(1);
        QFileInfo fileInfo(normalPath.toLower());
        // qDebug()<<"removing"<<normalPath;
        QString absolutePath = fileInfo.absoluteFilePath();
        QList<QWindowsFileSystemWatcherEngineThread *>::iterator jt, end;
        end = threads.end();
        for(jt = threads.begin(); jt!= end; ++jt) {
            QWindowsFileSystemWatcherEngineThread *thread = *jt;
            if (*jt == 0)
                continue;

            QMutexLocker locker(&(thread->mutex));

            QWindowsFileSystemWatcherEngine::Handle handle = thread->handleForDir.value(absolutePath);
            if (handle.handle == INVALID_HANDLE_VALUE) {
                // perhaps path is a file?
                absolutePath = fileInfo.absolutePath();
                handle = thread->handleForDir.value(absolutePath);
            }
            if (handle.handle != INVALID_HANDLE_VALUE) {
                QHash<QString, QWindowsFileSystemWatcherEngine::PathInfo> &h =
                        thread->pathInfoForHandle[handle.handle];
                if (h.remove(fileInfo.absoluteFilePath())) {
                    // ###
                    files->removeAll(path);
                    directories->removeAll(path);

                    if (h.isEmpty()) {
                        // qDebug() << "Closing handle" << handle.handle;
                        FindCloseChangeNotification(handle.handle);    // This one might generate a notification

                        int indexOfHandle = thread->handles.indexOf(handle.handle);
                        Q_ASSERT(indexOfHandle != -1);
                        thread->handles.remove(indexOfHandle);

                        thread->handleForDir.remove(absolutePath);
                        // h is now invalid

                        it.remove();

                        if (thread->handleForDir.isEmpty()) {
                            // qDebug()<<"Stopping thread "<<thread;
                            locker.unlock();
                            thread->stop();
                            thread->wait();
                            locker.relock();
                            // We can't delete the thread until the mutex locker is
                            // out of scope
                        }
                    }
                }
                // Found the file, go to next one
                break;
            }
        }
    }

    // Remove all threads that we stopped
    QList<QWindowsFileSystemWatcherEngineThread *>::iterator jt, end;
    end = threads.end();
    for(jt = threads.begin(); jt != end; ++jt) {
        if (!(*jt)->isRunning()) {
            delete *jt;
            *jt = 0;
        }
    }

    threads.removeAll(0);
    return p;
}

///////////
// QWindowsFileSystemWatcherEngineThread
///////////

QWindowsFileSystemWatcherEngineThread::QWindowsFileSystemWatcherEngineThread()
        : msg(0)
{
    if (HANDLE h = CreateEvent(0, false, false, 0)) {
        handles.reserve(MAXIMUM_WAIT_OBJECTS);
        handles.append(h);
    }
    moveToThread(this);
}


QWindowsFileSystemWatcherEngineThread::~QWindowsFileSystemWatcherEngineThread()
{
    CloseHandle(handles.at(0));
    handles[0] = INVALID_HANDLE_VALUE;

    foreach (HANDLE h, handles) {
        if (h == INVALID_HANDLE_VALUE)
            continue;
        FindCloseChangeNotification(h);
    }
}

void QWindowsFileSystemWatcherEngineThread::run()
{
    QMutexLocker locker(&mutex);
    forever {
        QVector<HANDLE> handlesCopy = handles;
        locker.unlock();
        // qDebug() << "QWindowsFileSystemWatcherThread"<<this<<"waiting on" << handlesCopy.count() << "handles";
        DWORD r = WaitForMultipleObjects(handlesCopy.count(), handlesCopy.constData(), false, INFINITE);
        locker.relock();
        do {
            if (r == WAIT_OBJECT_0) {
                int m = msg;
                msg = 0;
                if (m == 'q') {
                    // qDebug() << "thread"<<this<<"told to quit";
                    return;
                }
                if (m != '@')  {
                    qDebug("QWindowsFileSystemWatcherEngine: unknown message '%c' send to thread", char(m));
                }
                break;
            } else if (r > WAIT_OBJECT_0 && r < WAIT_OBJECT_0 + uint(handlesCopy.count())) {
                int at = r - WAIT_OBJECT_0;
                Q_ASSERT(at < handlesCopy.count());
                HANDLE handle = handlesCopy.at(at);

                // When removing a path, FindCloseChangeNotification might actually fire a notification
                // for some reason, so we must check if the handle exist in the handles vector
                if (handles.contains(handle)) {
                    // qDebug()<<"thread"<<this<<"Acknowledged handle:"<<at<<handle;
                    if (!FindNextChangeNotification(handle)) {
                        qErrnoWarning("QFileSystemWatcher: FindNextChangeNotification failed!!");
                    }

                    QHash<QString, QWindowsFileSystemWatcherEngine::PathInfo> &h = pathInfoForHandle[handle];
                    QMutableHashIterator<QString, QWindowsFileSystemWatcherEngine::PathInfo> it(h);
                    while (it.hasNext()) {
                        QHash<QString, QWindowsFileSystemWatcherEngine::PathInfo>::iterator x = it.next();
                        QString absolutePath = x.value().absolutePath;
                        QFileInfo fileInfo(x.value().path);
                        // qDebug() << "checking" << x.key();
                        if (!fileInfo.exists()) {
                            // qDebug() << x.key() << "removed!";
                            if (x.value().isDir)
                                emit directoryChanged(x.value().path, true);
                            else
                                emit fileChanged(x.value().path, true);
                            h.erase(x);

                            // close the notification handle if the directory has been removed
                            if (h.isEmpty()) {
                                // qDebug() << "Thread closing handle" << handle;
                                FindCloseChangeNotification(handle);    // This one might generate a notification

                                int indexOfHandle = handles.indexOf(handle);
                                Q_ASSERT(indexOfHandle != -1);
                                handles.remove(indexOfHandle);

                                handleForDir.remove(absolutePath);
                                // h is now invalid
                            }
                        } else if (x.value().isDir) {
                            // qDebug() << x.key() << "directory changed!";
                            emit directoryChanged(x.value().path, false);
                            x.value() = fileInfo;
                        } else if (x.value() != fileInfo) {
                            // qDebug() << x.key() << "file changed!";
                            emit fileChanged(x.value().path, false);
                            x.value() = fileInfo;
                        }
                    }
                }
            } else {
                // qErrnoWarning("QFileSystemWatcher: error while waiting for change notification");
                break;  // avoid endless loop
            }
            handlesCopy = handles;
            r = WaitForMultipleObjects(handlesCopy.count(), handlesCopy.constData(), false, 0);
        } while (r != WAIT_TIMEOUT);
    }
}


void QWindowsFileSystemWatcherEngineThread::stop()
{
    msg = 'q';
    SetEvent(handles.at(0));
}

void QWindowsFileSystemWatcherEngineThread::wakeup()
{
    msg = '@';
    SetEvent(handles.at(0));
}

QT_END_NAMESPACE
#endif // QT_NO_FILESYSTEMWATCHER