/* ============================================================
 *
 * This file is a part of digiKam project
 * http://www.digikam.org
 *
 * Date        : 2007-03-21
 * Description : Collection scanning to database.
 *
 * Copyright (C) 2005      by Renchi Raju <renchi dot raju at gmail dot com>
 * Copyright (C) 2005-2006 by Tom Albers <tomalbers@kde.nl>
 * Copyright (C) 2007-2011 by Marcel Wiesweg <marcel dot wiesweg at gmx dot de>
 *
 * This program is free software; you can redistribute it
 * and/or modify it under the terms of the GNU General
 * Public License as published by the Free Software Foundation;
 * either version 2, or (at your option)
 * any later version.
 *
 * This program 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 General Public License for more details.
 *
 * ============================================================ */

#ifndef COLLECTIONSCANNER_H
#define COLLECTIONSCANNER_H

// Qt includes

#include <QString>
#include <QObject>
#include <QList>

// Local includes

#include "digikam_export.h"
#include "coredbaccess.h"
#include "coredbalbuminfo.h"

class QFileInfo;

namespace Digikam
{

class AlbumCopyMoveHint;
class CollectionLocation;
class CollectionScannerObserver;
class ImageInfo;
class ItemCopyMoveHint;
class ItemChangeHint;
class ItemMetadataAdjustmentHint;

class CollectionScannerHintContainer
{
public:

    /// Note: All methods of this class must be thread-safe.

    virtual ~CollectionScannerHintContainer() {};

    virtual void recordHints(const QList<AlbumCopyMoveHint>& hints) = 0;
    virtual void recordHints(const QList<ItemCopyMoveHint>& hints) = 0;
    virtual void recordHints(const QList<ItemChangeHint>& hints) = 0;
    virtual void recordHint(const ItemMetadataAdjustmentHint& hints) = 0;

    virtual void clear() = 0;
};

// ------------------------------------------------------------------------------

class DIGIKAM_DATABASE_EXPORT CollectionScanner : public QObject
{
    Q_OBJECT

public:

    enum FileScanMode
    {
        /** The file will be scanned like it is done for any usual scan.
         *  If it was not modified, no further action is taken.
         *  If the file is not known yet, it will be fully scanned, or,
         *  if an identical file is found, this data will be copied. */
        NormalScan,
        /** The file will scanned like a modified file. Only a selected portion
         *  of the metadata will be updated into the database.
         *  If the file is not known yet, it will be fully scanned, or,
         *  if an identical file is found, this data will be copied.  */
        ModifiedScan,
        /** The file will be scanned like a completely new file.
         *  The complete metadata is re-read into the database.
         *  No search for identical files will be done. */
        Rescan
    };

public:

    CollectionScanner();
    ~CollectionScanner();

    /**
     * Carries out a full scan on all available parts of the collection.
     * Only a full scan can finally remove deleted files from the database,
     * only a full scan will mark the database as scanned.
     * The database will be locked while running (Note: this is not done for partialScans).
     */
    void completeScan();

    /**
     * If you enable deferred file scanning for a completeScan(), new files
     * will not be scanned. The relevant albums are available from
     * deferredAlbumPaths() when completeScan() has finished.
     * You need to call finishCompleteScan() afterwards with the list
     * to get the same complete scan than undeferred completeScan().
     */
    void finishCompleteScan(const QStringList& albumPaths);

    void setDeferredFileScanning(bool defer);
    QStringList deferredAlbumPaths() const;

    /**
     * Carries out a partial scan on the specified path of the collection.
     * The includes scanning for new files + albums and updating modified file data.
     * Files no longer found in the specified path however are not completely
     * removed, but only marked as removed. They will be removed only after a complete scan.
     */
    void partialScan(const QString& filePath);

    /**
     * Same procedure as above, but albumRoot and album is provided.
     */
    void partialScan(const QString& albumRoot, const QString& album);

    /**
     * The given file will be scanned according to the given mode.
     * Returns the image id of the file.
     */
    qlonglong scanFile(const QString& filePath, FileScanMode mode = ModifiedScan);

    /**
     * Same procedure as above, but albumRoot and album is provided.
     * If you already have this info it need not be retrieved.
     * Returns the image id of the file, or -1 on failure.
     */
    qlonglong scanFile(const QString& albumRoot, const QString& album, const QString& fileName, FileScanMode mode = ModifiedScan);

    /**
     * The given file represented by the ImageInfo will be scanned according to mode
     */
    void scanFile(const ImageInfo& info, FileScanMode mode = ModifiedScan);

    /**
     * Hints give the scanner additional info about things that happened in the past
     * carried out by higher level which the collection scanner cannot know.
     * They allow to carry out optimizations.
     * Record hints in a container, and provide the container to the collection scanner.
     * The Container set in setHintContainer must be one created by createContainer.
     */
    static CollectionScannerHintContainer* createHintContainer();
    void setHintContainer(CollectionScannerHintContainer* const container);
    void setUpdateHashHint(bool hint = true);

    /**
     * Call this to enable the progress info signals.
     * Default is off.
     */
    void setSignalsEnabled(bool on);

    /**
     * Call this to enable emitting the total files to scan
     * (for progress info) before a complete collection scan.
     * Default is off. If on, setSignalEnabled() must be on to take effect.
     */
    void setNeedFileCount(bool on);

    /**
     * Utility method:
     * Prepare the given albums to be removed,
     * typically by setting the albums as orphan
     * and removing all entries from the albums
     */
    void safelyRemoveAlbums(const QList<int>& albumIds);

    /**
     * Set an observer to be able to cancel a running scan
     */
    void setObserver(CollectionScannerObserver* const observer);

    /**
     * When a file is derived from another file, typically through editing,
     * copy all relevant attributes from source file to the new file.
     */
    static void copyFileProperties(const ImageInfo& source, const ImageInfo& dest);

    /**
     * Returns if the initial scan of the database has been done.
     * This is the first complete scan after creation of a new database file
     * (or update requiring a rescan)
     */
    static bool databaseInitialScanDone();

Q_SIGNALS:

    /**
     * Emitted once in scanAlbums(), the scan() methods, and updateItemsWithoutDate().
     * Gives the number of the files that need to be scanned.
     */
    void totalFilesToScan(int count);

    /**
     * Notifies the begin of the scanning of the specified album root,
     * album, of stale files, or of the whole collection (after stale files)
     */
    void startScanningAlbumRoot(const QString& albumRoot);
    void startScanningAlbum(const QString& albumRoot, const QString& album);
    void startScanningForStaleAlbums();
    void startScanningAlbumRoots();
    void startCompleteScan();

    /**
     * Emitted when the scanning has finished.
     * Note that start/finishScanningAlbum may be emitted recursively.
     */
    void finishedScanningAlbumRoot(const QString& albumRoot);
    void finishedScanningAlbum(const QString& albumRoot, const QString& album, int filesScanned);
    void finishedScanningForStaleAlbums();
    void finishedCompleteScan();

    /**
     * Emitted between startScanningAlbum and finishedScanningAlbum.
     * In between these two signals, the sum of filesScanned of all sent signals
     * equals the one reported by finishedScanningAlbum()
     */
    void scannedFiles(int filesScanned);
    /**
     * Emitted when the observer told to cancel the scan
     */
    void cancelled();

protected:

    void completeScanCleanupPart();
    void mainEntryPoint(bool complete);
    void scanForStaleAlbums(const QList<CollectionLocation>& locations);
    void scanForStaleAlbums(const QList<int>& locationIdsToScan);
    void scanAlbumRoot(const CollectionLocation& location);
    void scanAlbum(const CollectionLocation& location, const QString& album);
    int  checkAlbum(const CollectionLocation& location, const QString& album);
    void scanExistingFile(const QFileInfo& fi, qlonglong id);
    void scanFileNormal(const QFileInfo& info, const ItemScanInfo& scanInfo);
    void scanModifiedFile(const QFileInfo& info, const ItemScanInfo& scanInfo);
    void scanFileUpdateHashReuseThumbnail(const QFileInfo& fi, const ItemScanInfo& scanInfo, bool fileWasEdited);
    void rescanFile(const QFileInfo& info, const ItemScanInfo& scanInfo);
    void itemsWereRemoved(const QList<qlonglong> &removedIds);
    void completeHistoryScanning();
    void finishHistoryScanning();
    void historyScanningStage2(const QList<qlonglong>& ids);
    void historyScanningStage3(const QList<qlonglong>& ids);

    void markDatabaseAsScanned();
    void updateRemovedItemsTime();
    void incrementDeleteRemovedCompleteScanCount();
    void resetDeleteRemovedSettings();
    bool checkDeleteRemoved();
    void loadNameFilters();
    int countItemsInFolder(const QString& directory);
    DatabaseItem::Category category(const QFileInfo& info);

    qlonglong scanFile(const QFileInfo& fi, int albumId, qlonglong id, FileScanMode mode);
    qlonglong scanNewFile(const QFileInfo& info, int albumId);
    qlonglong scanNewFileFullScan(const QFileInfo& info, int albumId);

private:

    class Private;
    Private* const d;
};

}  // namespace Digikam

#endif // COLLECTIONSCANNER_H
