/*
 * Copyright (C) by Klaas Freitag <freitag@owncloud.com>
 *
 * 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 of the License, 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.
 */

#include "folderman.h"
#include "configfile.h"
#include "folder.h"
#include "syncresult.h"
#include "theme.h"
#include "socketapi.h"
#include "account.h"
#include "accountstate.h"
#include "accountmanager.h"
#include "filesystem.h"
#include "lockwatcher.h"
#include "common/asserts.h"
#include <syncengine.h>

#ifdef Q_OS_MAC
#include <CoreServices/CoreServices.h>
#endif

#include <QMessageBox>
#include <QtCore>
#include <QMutableSetIterator>
#include <QSet>
#include <QNetworkProxy>

static const char versionC[] = "version";
static const int maxFoldersVersion = 1;

namespace OCC {

Q_LOGGING_CATEGORY(lcFolderMan, "gui.folder.manager", QtInfoMsg)

FolderMan *FolderMan::_instance = 0;

FolderMan::FolderMan(QObject *parent)
    : QObject(parent)
    , _currentSyncFolder(0)
    , _syncEnabled(true)
    , _lockWatcher(new LockWatcher)
    , _navigationPaneHelper(this)
    , _appRestartRequired(false)
{
    ASSERT(!_instance);
    _instance = this;

    _socketApi.reset(new SocketApi);

    ConfigFile cfg;
    std::chrono::milliseconds polltime = cfg.remotePollInterval();
    qCInfo(lcFolderMan) << "setting remote poll timer interval to" << polltime.count() << "msec";
    _etagPollTimer.setInterval(polltime.count());
    QObject::connect(&_etagPollTimer, &QTimer::timeout, this, &FolderMan::slotEtagPollTimerTimeout);
    _etagPollTimer.start();

    _startScheduledSyncTimer.setSingleShot(true);
    connect(&_startScheduledSyncTimer, &QTimer::timeout,
        this, &FolderMan::slotStartScheduledFolderSync);

    _timeScheduler.setInterval(5000);
    _timeScheduler.setSingleShot(false);
    connect(&_timeScheduler, &QTimer::timeout,
        this, &FolderMan::slotScheduleFolderByTime);
    _timeScheduler.start();

    connect(AccountManager::instance(), &AccountManager::accountRemoved,
        this, &FolderMan::slotRemoveFoldersForAccount);

    connect(_lockWatcher.data(), &LockWatcher::fileUnlocked,
        this, &FolderMan::slotWatchedFileUnlocked);
}

FolderMan *FolderMan::instance()
{
    return _instance;
}

FolderMan::~FolderMan()
{
    qDeleteAll(_folderMap);
    _instance = 0;
}

OCC::Folder::Map FolderMan::map() const
{
    return _folderMap;
}

QList<Folder *> FolderMan::list() const
{
    return _folderMap.values();
}

void FolderMan::unloadFolder(Folder *f)
{
    if (!f) {
        return;
    }

    _socketApi->slotUnregisterPath(f->alias());

    _folderMap.remove(f->alias());

    disconnect(f, &Folder::syncStarted,
        this, &FolderMan::slotFolderSyncStarted);
    disconnect(f, &Folder::syncFinished,
        this, &FolderMan::slotFolderSyncFinished);
    disconnect(f, &Folder::syncStateChange,
        this, &FolderMan::slotForwardFolderSyncStateChange);
    disconnect(f, &Folder::syncPausedChanged,
        this, &FolderMan::slotFolderSyncPaused);
    disconnect(&f->syncEngine().syncFileStatusTracker(), &SyncFileStatusTracker::fileStatusChanged,
        _socketApi.data(), &SocketApi::broadcastStatusPushMessage);
    disconnect(f, &Folder::watchedFileChangedExternally,
        &f->syncEngine().syncFileStatusTracker(), &SyncFileStatusTracker::slotPathTouched);
}

int FolderMan::unloadAndDeleteAllFolders()
{
    int cnt = 0;

    // clear the list of existing folders.
    Folder::MapIterator i(_folderMap);
    while (i.hasNext()) {
        i.next();
        Folder *f = i.value();
        unloadFolder(f);
        delete f;
        cnt++;
    }
    ASSERT(_folderMap.isEmpty());

    _lastSyncFolder = 0;
    _currentSyncFolder = 0;
    _scheduledFolders.clear();
    emit folderListChanged(_folderMap);
    emit scheduleQueueChanged();

    return cnt;
}

void FolderMan::registerFolderWithSocketApi(Folder *folder)
{
    if (!folder)
        return;
    if (!QDir(folder->path()).exists())
        return;

    // register the folder with the socket API
    if (folder->canSync())
        _socketApi->slotRegisterPath(folder->alias());
}

int FolderMan::setupFolders()
{
    unloadAndDeleteAllFolders();

    QStringList skipSettingsKeys, deleteSettingsKeys;
    backwardMigrationSettingsKeys(&deleteSettingsKeys, &skipSettingsKeys);
    // deleteKeys should already have been deleted on application startup.
    // We ignore them here just in case.
    skipSettingsKeys += deleteSettingsKeys;

    auto settings = ConfigFile::settingsWithGroup(QLatin1String("Accounts"));
    const auto accountsWithSettings = settings->childGroups();
    if (accountsWithSettings.isEmpty()) {
        int r = setupFoldersMigration();
        if (r > 0) {
            AccountManager::instance()->save(false); // don't save credentials, they had not been loaded from keychain
        }
        return r;
    }

    qCInfo(lcFolderMan) << "Setup folders from settings file";

    foreach (const auto &account, AccountManager::instance()->accounts()) {
        const auto id = account->account()->id();
        if (!accountsWithSettings.contains(id)) {
            continue;
        }
        settings->beginGroup(id);

        // The "backwardsCompatible" flag here is related to migrating old
        // database locations
        auto process = [&](const QString &groupName, bool backwardsCompatible, bool foldersWithPlaceholders) {
            settings->beginGroup(groupName);
            if (skipSettingsKeys.contains(settings->group())) {
                // Should not happen: bad container keys should have been deleted
                qCWarning(lcFolderMan) << "Folder structure" << groupName << "is too new, ignoring";
            } else {
                setupFoldersHelper(*settings, account, skipSettingsKeys, backwardsCompatible, foldersWithPlaceholders);
            }
            settings->endGroup();
        };

        process(QStringLiteral("Folders"), true, false);

        // See Folder::saveToSettings for details about why these exists.
        process(QStringLiteral("Multifolders"), false, false);
        process(QStringLiteral("FoldersWithPlaceholders"), false, true);

        settings->endGroup(); // <account>
    }

    emit folderListChanged(_folderMap);

    return _folderMap.size();
}

void FolderMan::setupFoldersHelper(QSettings &settings, AccountStatePtr account, const QStringList &ignoreKeys, bool backwardsCompatible, bool foldersWithPlaceholders)
{
    foreach (const auto &folderAlias, settings.childGroups()) {
        // Skip folders with too-new version
        settings.beginGroup(folderAlias);
        if (ignoreKeys.contains(settings.group())) {
            qCInfo(lcFolderMan) << "Folder" << folderAlias << "is too new, ignoring";
            _additionalBlockedFolderAliases.insert(folderAlias);
            settings.endGroup();
            continue;
        }
        settings.endGroup();

        FolderDefinition folderDefinition;
        settings.beginGroup(folderAlias);
        if (FolderDefinition::load(settings, folderAlias, &folderDefinition)) {
            auto defaultJournalPath = folderDefinition.defaultJournalPath(account->account());

            // Migration: Old settings don't have journalPath
            if (folderDefinition.journalPath.isEmpty()) {
                folderDefinition.journalPath = defaultJournalPath;
            }

            // Migration: ._ files sometimes can't be created.
            // So if the configured journalPath has a dot-underscore ("._sync_*.db")
            // but the current default doesn't have the underscore, switch to the
            // new default if no db exists yet.
            if (folderDefinition.journalPath.startsWith("._sync_")
                && defaultJournalPath.startsWith(".sync_")
                && !QFile::exists(folderDefinition.absoluteJournalPath())) {
                folderDefinition.journalPath = defaultJournalPath;
            }

            // Migration: If an old db is found, move it to the new name.
            if (backwardsCompatible) {
                SyncJournalDb::maybeMigrateDb(folderDefinition.localPath, folderDefinition.absoluteJournalPath());
            }

            auto vfs = createVfsFromPlugin(folderDefinition.virtualFilesMode);
            if (!vfs) {
                // TODO: Must do better error handling
                qFatal("Could not load plugin");
            }

            Folder *f = addFolderInternal(std::move(folderDefinition), account.data(), std::move(vfs));
            if (f) {
                // Migrate the old "usePlaceholders" setting to the root folder pin state
                if (settings.value(QLatin1String(versionC), 1).toInt() == 1
                    && settings.value(QLatin1String("usePlaceholders"), false).toBool()) {
                    f->setRootPinState(PinState::OnlineOnly);
                }

                // Migration: Mark folders that shall be saved in a backwards-compatible way
                if (backwardsCompatible)
                    f->setSaveBackwardsCompatible(true);
                if (foldersWithPlaceholders)
                    f->setSaveInFoldersWithPlaceholders();

                scheduleFolder(f);
                emit folderSyncStateChange(f);
            }
        }
        settings.endGroup();
    }
}

int FolderMan::setupFoldersMigration()
{
    ConfigFile cfg;
    QDir storageDir(cfg.configPath());
    _folderConfigPath = cfg.configPath() + QLatin1String("folders");

    qCInfo(lcFolderMan) << "Setup folders from " << _folderConfigPath << "(migration)";

    QDir dir(_folderConfigPath);
    //We need to include hidden files just in case the alias starts with '.'
    dir.setFilter(QDir::Files | QDir::Hidden);
    QStringList list = dir.entryList();

    // Normally there should be only one account when migrating.
    AccountState *accountState = AccountManager::instance()->accounts().value(0).data();
    foreach (const QString &alias, list) {
        Folder *f = setupFolderFromOldConfigFile(alias, accountState);
        if (f) {
            scheduleFolder(f);
            emit folderSyncStateChange(f);
        }
    }

    emit folderListChanged(_folderMap);

    // return the number of valid folders.
    return _folderMap.size();
}

void FolderMan::backwardMigrationSettingsKeys(QStringList *deleteKeys, QStringList *ignoreKeys)
{
    auto settings = ConfigFile::settingsWithGroup(QLatin1String("Accounts"));

    auto processSubgroup = [&](const QString &name) {
        settings->beginGroup(name);
        const int foldersVersion = settings->value(QLatin1String(versionC), 1).toInt();
        if (foldersVersion <= maxFoldersVersion) {
            foreach (const auto &folderAlias, settings->childGroups()) {
                settings->beginGroup(folderAlias);
                const int folderVersion = settings->value(QLatin1String(versionC), 1).toInt();
                if (folderVersion > FolderDefinition::maxSettingsVersion()) {
                    ignoreKeys->append(settings->group());
                }
                settings->endGroup();
            }
        } else {
            deleteKeys->append(settings->group());
        }
        settings->endGroup();
    };

    for (const auto &accountId : settings->childGroups()) {
        settings->beginGroup(accountId);
        processSubgroup("Folders");
        processSubgroup("Multifolders");
        processSubgroup("FoldersWithPlaceholders");
        settings->endGroup();
    }
}

bool FolderMan::ensureJournalGone(const QString &journalDbFile)
{
    // remove the old journal file
    while (QFile::exists(journalDbFile) && !QFile::remove(journalDbFile)) {
        qCWarning(lcFolderMan) << "Could not remove old db file at" << journalDbFile;
        int ret = QMessageBox::warning(0, tr("Could not reset folder state"),
            tr("An old sync journal '%1' was found, "
               "but could not be removed. Please make sure "
               "that no application is currently using it.")
                .arg(QDir::fromNativeSeparators(QDir::cleanPath(journalDbFile))),
            QMessageBox::Retry | QMessageBox::Abort);
        if (ret == QMessageBox::Abort) {
            return false;
        }
    }
    return true;
}

#define SLASH_TAG QLatin1String("__SLASH__")
#define BSLASH_TAG QLatin1String("__BSLASH__")
#define QMARK_TAG QLatin1String("__QMARK__")
#define PERCENT_TAG QLatin1String("__PERCENT__")
#define STAR_TAG QLatin1String("__STAR__")
#define COLON_TAG QLatin1String("__COLON__")
#define PIPE_TAG QLatin1String("__PIPE__")
#define QUOTE_TAG QLatin1String("__QUOTE__")
#define LT_TAG QLatin1String("__LESS_THAN__")
#define GT_TAG QLatin1String("__GREATER_THAN__")
#define PAR_O_TAG QLatin1String("__PAR_OPEN__")
#define PAR_C_TAG QLatin1String("__PAR_CLOSE__")

QString FolderMan::escapeAlias(const QString &alias)
{
    QString a(alias);

    a.replace(QLatin1Char('/'), SLASH_TAG);
    a.replace(QLatin1Char('\\'), BSLASH_TAG);
    a.replace(QLatin1Char('?'), QMARK_TAG);
    a.replace(QLatin1Char('%'), PERCENT_TAG);
    a.replace(QLatin1Char('*'), STAR_TAG);
    a.replace(QLatin1Char(':'), COLON_TAG);
    a.replace(QLatin1Char('|'), PIPE_TAG);
    a.replace(QLatin1Char('"'), QUOTE_TAG);
    a.replace(QLatin1Char('<'), LT_TAG);
    a.replace(QLatin1Char('>'), GT_TAG);
    a.replace(QLatin1Char('['), PAR_O_TAG);
    a.replace(QLatin1Char(']'), PAR_C_TAG);
    return a;
}

SocketApi *FolderMan::socketApi()
{
    return this->_socketApi.data();
}

QString FolderMan::unescapeAlias(const QString &alias)
{
    QString a(alias);

    a.replace(SLASH_TAG, QLatin1String("/"));
    a.replace(BSLASH_TAG, QLatin1String("\\"));
    a.replace(QMARK_TAG, QLatin1String("?"));
    a.replace(PERCENT_TAG, QLatin1String("%"));
    a.replace(STAR_TAG, QLatin1String("*"));
    a.replace(COLON_TAG, QLatin1String(":"));
    a.replace(PIPE_TAG, QLatin1String("|"));
    a.replace(QUOTE_TAG, QLatin1String("\""));
    a.replace(LT_TAG, QLatin1String("<"));
    a.replace(GT_TAG, QLatin1String(">"));
    a.replace(PAR_O_TAG, QLatin1String("["));
    a.replace(PAR_C_TAG, QLatin1String("]"));

    return a;
}

// filename is the name of the file only, it does not include
// the configuration directory path
// WARNING: Do not remove this code, it is used for predefined/automated deployments (2016)
Folder *FolderMan::setupFolderFromOldConfigFile(const QString &file, AccountState *accountState)
{
    Folder *folder = 0;

    qCInfo(lcFolderMan) << "  ` -> setting up:" << file;
    QString escapedAlias(file);
    // check the unescaped variant (for the case when the filename comes out
    // of the directory listing). If the file does not exist, escape the
    // file and try again.
    QFileInfo cfgFile(_folderConfigPath, file);

    if (!cfgFile.exists()) {
        // try the escaped variant.
        escapedAlias = escapeAlias(file);
        cfgFile.setFile(_folderConfigPath, escapedAlias);
    }
    if (!cfgFile.isReadable()) {
        qCWarning(lcFolderMan) << "Cannot read folder definition for alias " << cfgFile.filePath();
        return folder;
    }

    QSettings settings(_folderConfigPath + QLatin1Char('/') + escapedAlias, QSettings::IniFormat);
    qCInfo(lcFolderMan) << "    -> file path: " << settings.fileName();

    // Check if the filename is equal to the group setting. If not, use the group
    // name as an alias.
    QStringList groups = settings.childGroups();

    if (!groups.contains(escapedAlias) && groups.count() > 0) {
        escapedAlias = groups.first();
    }

    settings.beginGroup(escapedAlias); // read the group with the same name as the file which is the folder alias

    QString path = settings.value(QLatin1String("localPath")).toString();
    QString backend = settings.value(QLatin1String("backend")).toString();
    QString targetPath = settings.value(QLatin1String("targetPath")).toString();
    bool paused = settings.value(QLatin1String("paused"), false).toBool();
    // QString connection = settings.value( QLatin1String("connection") ).toString();
    QString alias = unescapeAlias(escapedAlias);

    if (backend.isEmpty() || backend != QLatin1String("owncloud")) {
        qCWarning(lcFolderMan) << "obsolete configuration of type" << backend;
        return 0;
    }

    // cut off the leading slash, oCUrl always has a trailing.
    if (targetPath.startsWith(QLatin1Char('/'))) {
        targetPath.remove(0, 1);
    }

    if (!accountState) {
        qCCritical(lcFolderMan) << "can't create folder without an account";
        return 0;
    }

    FolderDefinition folderDefinition;
    folderDefinition.alias = alias;
    folderDefinition.localPath = path;
    folderDefinition.targetPath = targetPath;
    folderDefinition.paused = paused;
    folderDefinition.ignoreHiddenFiles = ignoreHiddenFiles();

    folder = addFolderInternal(folderDefinition, accountState, std::make_unique<VfsOff>());
    if (folder) {
        QStringList blackList = settings.value(QLatin1String("blackList")).toStringList();
        if (!blackList.empty()) {
            //migrate settings
            folder->journalDb()->setSelectiveSyncList(SyncJournalDb::SelectiveSyncBlackList, blackList);
            settings.remove(QLatin1String("blackList"));
            // FIXME: If you remove this codepath, you need to provide another way to do
            // this via theme.h or the normal FolderMan::setupFolders
        }

        folder->saveToSettings();
    }
    qCInfo(lcFolderMan) << "Migrated!" << folder;
    settings.sync();
    return folder;
}

void FolderMan::slotFolderSyncPaused(Folder *f, bool paused)
{
    if (!f) {
        qCCritical(lcFolderMan) << "slotFolderSyncPaused called with empty folder";
        return;
    }

    if (!paused) {
        _disabledFolders.remove(f);
        scheduleFolder(f);
    } else {
        _disabledFolders.insert(f);
    }
}

void FolderMan::slotFolderCanSyncChanged()
{
    Folder *f = qobject_cast<Folder *>(sender());
    ASSERT(f);
    if (f->canSync()) {
        _socketApi->slotRegisterPath(f->alias());
    } else {
        _socketApi->slotUnregisterPath(f->alias());
    }
}

Folder *FolderMan::folder(const QString &alias)
{
    if (!alias.isEmpty()) {
        if (_folderMap.contains(alias)) {
            return _folderMap[alias];
        }
    }
    return 0;
}

void FolderMan::scheduleAllFolders()
{
    foreach (Folder *f, _folderMap.values()) {
        if (f && f->canSync()) {
            scheduleFolder(f);
        }
    }
}

void FolderMan::slotScheduleAppRestart()
{
    _appRestartRequired = true;
    qCInfo(lcFolderMan) << "Application restart requested!";
}

void FolderMan::slotSyncOnceFileUnlocks(const QString &path)
{
    _lockWatcher->addFile(path);
}

/*
  * if a folder wants to be synced, it calls this slot and is added
  * to the queue. The slot to actually start a sync is called afterwards.
  */
void FolderMan::scheduleFolder(Folder *f)
{
    if (!f) {
        qCCritical(lcFolderMan) << "slotScheduleSync called with null folder";
        return;
    }
    auto alias = f->alias();

    qCInfo(lcFolderMan) << "Schedule folder " << alias << " to sync!";

    if (!_scheduledFolders.contains(f)) {
        if (!f->canSync()) {
            qCInfo(lcFolderMan) << "Folder is not ready to sync, not scheduled!";
            _socketApi->slotUpdateFolderView(f);
            return;
        }
        f->prepareToSync();
        emit folderSyncStateChange(f);
        _scheduledFolders.enqueue(f);
        emit scheduleQueueChanged();
    } else {
        qCInfo(lcFolderMan) << "Sync for folder " << alias << " already scheduled, do not enqueue!";
    }

    startScheduledSyncSoon();
}

void FolderMan::scheduleFolderNext(Folder *f)
{
    auto alias = f->alias();
    qCInfo(lcFolderMan) << "Schedule folder " << alias << " to sync! Front-of-queue.";

    if (!f->canSync()) {
        qCInfo(lcFolderMan) << "Folder is not ready to sync, not scheduled!";
        return;
    }

    _scheduledFolders.removeAll(f);

    f->prepareToSync();
    emit folderSyncStateChange(f);
    _scheduledFolders.prepend(f);
    emit scheduleQueueChanged();

    startScheduledSyncSoon();
}

void FolderMan::slotScheduleETagJob(const QString & /*alias*/, RequestEtagJob *job)
{
    QObject::connect(job, &QObject::destroyed, this, &FolderMan::slotEtagJobDestroyed);
    QMetaObject::invokeMethod(this, "slotRunOneEtagJob", Qt::QueuedConnection);
    // maybe: add to queue
}

void FolderMan::slotEtagJobDestroyed(QObject * /*o*/)
{
    // _currentEtagJob is automatically cleared
    // maybe: remove from queue
    QMetaObject::invokeMethod(this, "slotRunOneEtagJob", Qt::QueuedConnection);
}

void FolderMan::slotRunOneEtagJob()
{
    if (_currentEtagJob.isNull()) {
        Folder *folder = nullptr;
        foreach (Folder *f, _folderMap) {
            if (f->etagJob()) {
                // Caveat: always grabs the first folder with a job, but we think this is Ok for now and avoids us having a seperate queue.
                _currentEtagJob = f->etagJob();
                folder = f;
                break;
            }
        }
        if (_currentEtagJob.isNull()) {
            //qCDebug(lcFolderMan) << "No more remote ETag check jobs to schedule.";

            /* now it might be a good time to check for restarting... */
            if (!isAnySyncRunning() && _appRestartRequired) {
                restartApplication();
            }
        } else {
            qCDebug(lcFolderMan) << "Scheduling" << folder->remoteUrl().toString() << "to check remote ETag";
            _currentEtagJob->start(); // on destroy/end it will continue the queue via slotEtagJobDestroyed
        }
    }
}

void FolderMan::slotAccountStateChanged()
{
    AccountState *accountState = qobject_cast<AccountState *>(sender());
    if (!accountState) {
        return;
    }
    QString accountName = accountState->account()->displayName();

    if (accountState->isConnected()) {
        qCInfo(lcFolderMan) << "Account" << accountName << "connected, scheduling its folders";

        foreach (Folder *f, _folderMap.values()) {
            if (f
                && f->canSync()
                && f->accountState() == accountState) {
                scheduleFolder(f);
            }
        }
    } else {
        qCInfo(lcFolderMan) << "Account" << accountName << "disconnected or paused, "
                                                           "terminating or descheduling sync folders";

        foreach (Folder *f, _folderMap.values()) {
            if (f
                && f->isSyncRunning()
                && f->accountState() == accountState) {
                f->slotTerminateSync();
            }
        }

        QMutableListIterator<Folder *> it(_scheduledFolders);
        while (it.hasNext()) {
            Folder *f = it.next();
            if (f->accountState() == accountState) {
                it.remove();
            }
        }
        emit scheduleQueueChanged();
    }
}

// only enable or disable foldermans will schedule and do syncs.
// this is not the same as Pause and Resume of folders.
void FolderMan::setSyncEnabled(bool enabled)
{
    if (!_syncEnabled && enabled && !_scheduledFolders.isEmpty()) {
        // We have things in our queue that were waiting for the connection to come back on.
        startScheduledSyncSoon();
    }
    _syncEnabled = enabled;
    // force a redraw in case the network connect status changed
    emit(folderSyncStateChange(0));
}

void FolderMan::startScheduledSyncSoon()
{
    if (_startScheduledSyncTimer.isActive()) {
        return;
    }
    if (_scheduledFolders.empty()) {
        return;
    }
    if (isAnySyncRunning()) {
        return;
    }

    qint64 msDelay = 100; // 100ms minimum delay
    qint64 msSinceLastSync = 0;

    // Require a pause based on the duration of the last sync run.
    if (Folder *lastFolder = _lastSyncFolder) {
        msSinceLastSync = lastFolder->msecSinceLastSync().count();

        //  1s   -> 1.5s pause
        // 10s   -> 5s pause
        //  1min -> 12s pause
        //  1h   -> 90s pause
        qint64 pause = qSqrt(lastFolder->msecLastSyncDuration().count()) / 20.0 * 1000.0;
        msDelay = qMax(msDelay, pause);
    }

    // Delays beyond one minute seem too big, particularly since there
    // could be things later in the queue that shouldn't be punished by a
    // long delay!
    msDelay = qMin(msDelay, 60 * 1000ll);

    // Time since the last sync run counts against the delay
    msDelay = qMax(1ll, msDelay - msSinceLastSync);

    qCInfo(lcFolderMan) << "Starting the next scheduled sync in" << (msDelay / 1000) << "seconds";
    _startScheduledSyncTimer.start(msDelay);
}

/*
  * slot to start folder syncs.
  * It is either called from the slot where folders enqueue themselves for
  * syncing or after a folder sync was finished.
  */
void FolderMan::slotStartScheduledFolderSync()
{
    if (isAnySyncRunning()) {
        for (auto f : _folderMap) {
            if (f->isSyncRunning())
                qCInfo(lcFolderMan) << "Currently folder " << f->remoteUrl().toString() << " is running, wait for finish!";
        }
        return;
    }

    if (!_syncEnabled) {
        qCInfo(lcFolderMan) << "FolderMan: Syncing is disabled, no scheduling.";
        return;
    }

    qCDebug(lcFolderMan) << "folderQueue size: " << _scheduledFolders.count();
    if (_scheduledFolders.isEmpty()) {
        return;
    }

    // Find the first folder in the queue that can be synced.
    Folder *folder = 0;
    while (!_scheduledFolders.isEmpty()) {
        Folder *g = _scheduledFolders.dequeue();
        if (g->canSync()) {
            folder = g;
            break;
        }
    }

    emit scheduleQueueChanged();

    // Start syncing this folder!
    if (folder) {
        // Safe to call several times, and necessary to try again if
        // the folder path didn't exist previously.
        folder->registerFolderWatcher();
        registerFolderWithSocketApi(folder);

        _currentSyncFolder = folder;
        folder->startSync(QStringList());
    }
}

void FolderMan::slotEtagPollTimerTimeout()
{
    ConfigFile cfg;
    auto polltime = cfg.remotePollInterval();

    foreach (Folder *f, _folderMap) {
        if (!f) {
            continue;
        }
        if (f->isSyncRunning()) {
            continue;
        }
        if (_scheduledFolders.contains(f)) {
            continue;
        }
        if (_disabledFolders.contains(f)) {
            continue;
        }
        if (f->etagJob() || f->isBusy() || !f->canSync()) {
            continue;
        }
        if (f->msecSinceLastSync() < polltime) {
            continue;
        }
        QMetaObject::invokeMethod(f, "slotRunEtagJob", Qt::QueuedConnection);
    }
}

void FolderMan::slotRemoveFoldersForAccount(AccountState *accountState)
{
    QVarLengthArray<Folder *, 16> foldersToRemove;
    Folder::MapIterator i(_folderMap);
    while (i.hasNext()) {
        i.next();
        Folder *folder = i.value();
        if (folder->accountState() == accountState) {
            foldersToRemove.append(folder);
        }
    }

    foreach (const auto &f, foldersToRemove) {
        removeFolder(f);
    }
}

void FolderMan::slotForwardFolderSyncStateChange()
{
    if (Folder *f = qobject_cast<Folder *>(sender())) {
        emit folderSyncStateChange(f);
    }
}

void FolderMan::slotServerVersionChanged(Account *account)
{
    // Pause folders if the server version is unsupported
    if (account->serverVersionUnsupported()) {
        qCWarning(lcFolderMan) << "The server version is unsupported:" << account->serverVersion()
                               << "pausing all folders on the account";

        foreach (auto &f, _folderMap) {
            if (f->accountState()->account().data() == account) {
                f->setSyncPaused(true);
            }
        }
    }
}

void FolderMan::slotWatchedFileUnlocked(const QString &path)
{
    if (Folder *f = folderForPath(path)) {
        // Treat this equivalently to the file being reported by the file watcher
        f->slotWatchedPathChanged(path, Folder::ChangeReason::UnLock);
    }
}

void FolderMan::slotScheduleFolderByTime()
{
    foreach (auto &f, _folderMap) {
        // Never schedule if syncing is disabled or when we're currently
        // querying the server for etags
        if (!f->canSync() || f->etagJob()) {
            continue;
        }

        auto msecsSinceSync = f->msecSinceLastSync();

        // Possibly it's just time for a new sync run
        bool forceSyncIntervalExpired = msecsSinceSync > ConfigFile().forceSyncInterval();
        if (forceSyncIntervalExpired) {
            qCInfo(lcFolderMan) << "Scheduling folder" << f->alias()
                                << "because it has been" << msecsSinceSync.count() << "ms "
                                << "since the last sync";

            scheduleFolder(f);
            continue;
        }

        // Retry a couple of times after failure; or regularly if requested
        bool syncAgain =
            (f->consecutiveFailingSyncs() > 0 && f->consecutiveFailingSyncs() < 3)
            || f->syncEngine().isAnotherSyncNeeded() == DelayedFollowUp;
        auto syncAgainDelay = std::chrono::seconds(10); // 10s for the first retry-after-fail
        if (f->consecutiveFailingSyncs() > 1)
            syncAgainDelay = std::chrono::seconds(60); // 60s for each further attempt
        if (syncAgain && msecsSinceSync > syncAgainDelay) {
            qCInfo(lcFolderMan) << "Scheduling folder" << f->alias()
                                << ", the last" << f->consecutiveFailingSyncs() << "syncs failed"
                                << ", anotherSyncNeeded" << f->syncEngine().isAnotherSyncNeeded()
                                << ", last status:" << f->syncResult().statusString()
                                << ", time since last sync:" << msecsSinceSync.count();

            scheduleFolder(f);
            continue;
        }

        // Do we want to retry failing syncs or another-sync-needed runs more often?
    }
}

bool FolderMan::isAnySyncRunning() const
{
    if (_currentSyncFolder)
        return true;

    for (auto f : _folderMap) {
        if (f->isSyncRunning())
            return true;
    }
    return false;
}

void FolderMan::slotFolderSyncStarted()
{
    auto f = qobject_cast<Folder *>(sender());
    ASSERT(f);
    if (!f)
        return;

    qCInfo(lcFolderMan, ">========== Sync started for folder [%s] of account [%s] with remote [%s]",
        qPrintable(f->shortGuiLocalPath()),
        qPrintable(f->accountState()->account()->displayName()),
        qPrintable(f->remoteUrl().toString()));
}

/*
  * a folder indicates that its syncing is finished.
  * Start the next sync after the system had some milliseconds to breath.
  * This delay is particularly useful to avoid late file change notifications
  * (that we caused ourselves by syncing) from triggering another spurious sync.
  */
void FolderMan::slotFolderSyncFinished(const SyncResult &)
{
    auto f = qobject_cast<Folder *>(sender());
    ASSERT(f);
    if (!f)
        return;

    qCInfo(lcFolderMan, "<========== Sync finished for folder [%s] of account [%s] with remote [%s]",
        qPrintable(f->shortGuiLocalPath()),
        qPrintable(f->accountState()->account()->displayName()),
        qPrintable(f->remoteUrl().toString()));

    if (f == _currentSyncFolder) {
        _lastSyncFolder = _currentSyncFolder;
        _currentSyncFolder = 0;
    }
    if (!isAnySyncRunning())
        startScheduledSyncSoon();
}

Folder *FolderMan::addFolder(AccountState *accountState, const FolderDefinition &folderDefinition)
{
    // Choose a db filename
    auto definition = folderDefinition;
    definition.journalPath = definition.defaultJournalPath(accountState->account());

    if (!ensureJournalGone(definition.absoluteJournalPath())) {
        return 0;
    }

    auto vfs = createVfsFromPlugin(folderDefinition.virtualFilesMode);
    if (!vfs) {
        qCWarning(lcFolderMan) << "Could not load plugin for mode" << folderDefinition.virtualFilesMode;
        return 0;
    }

    auto folder = addFolderInternal(definition, accountState, std::move(vfs));

    // Migration: The first account that's configured for a local folder shall
    // be saved in a backwards-compatible way.
    bool oneAccountOnly = true;
    foreach (Folder *other, FolderMan::instance()->map()) {
        if (other != folder && other->cleanPath() == folder->cleanPath()) {
            oneAccountOnly = false;
            break;
        }
    }

    if (folder) {
        folder->setSaveBackwardsCompatible(oneAccountOnly);
        folder->saveToSettings();
        emit folderSyncStateChange(folder);
        emit folderListChanged(_folderMap);
    }

    _navigationPaneHelper.scheduleUpdateCloudStorageRegistry();
    return folder;
}

Folder *FolderMan::addFolderInternal(
    FolderDefinition folderDefinition,
    AccountState *accountState,
    std::unique_ptr<Vfs> vfs)
{
    auto alias = folderDefinition.alias;
    int count = 0;
    while (folderDefinition.alias.isEmpty()
        || _folderMap.contains(folderDefinition.alias)
        || _additionalBlockedFolderAliases.contains(folderDefinition.alias)) {
        // There is already a folder configured with this name and folder names need to be unique
        folderDefinition.alias = alias + QString::number(++count);
    }

    auto folder = new Folder(folderDefinition, accountState, std::move(vfs), this);

    qCInfo(lcFolderMan) << "Adding folder to Folder Map " << folder << folder->alias();
    _folderMap[folder->alias()] = folder;
    if (folder->syncPaused()) {
        _disabledFolders.insert(folder);
    }

    // See matching disconnects in unloadFolder().
    connect(folder, &Folder::syncStarted, this, &FolderMan::slotFolderSyncStarted);
    connect(folder, &Folder::syncFinished, this, &FolderMan::slotFolderSyncFinished);
    connect(folder, &Folder::syncStateChange, this, &FolderMan::slotForwardFolderSyncStateChange);
    connect(folder, &Folder::syncPausedChanged, this, &FolderMan::slotFolderSyncPaused);
    connect(folder, &Folder::canSyncChanged, this, &FolderMan::slotFolderCanSyncChanged);
    connect(&folder->syncEngine().syncFileStatusTracker(), &SyncFileStatusTracker::fileStatusChanged,
        _socketApi.data(), &SocketApi::broadcastStatusPushMessage);
    connect(folder, &Folder::watchedFileChangedExternally,
        &folder->syncEngine().syncFileStatusTracker(), &SyncFileStatusTracker::slotPathTouched);

    folder->registerFolderWatcher();
    registerFolderWithSocketApi(folder);
    return folder;
}

Folder *FolderMan::folderForPath(const QString &path, QString *relativePath)
{
    QString absolutePath = QDir::cleanPath(path) + QLatin1Char('/');

    foreach (Folder *folder, this->map().values()) {
        const QString folderPath = folder->cleanPath() + QLatin1Char('/');

        if (absolutePath.startsWith(folderPath, (Utility::isWindows() || Utility::isMac()) ? Qt::CaseInsensitive : Qt::CaseSensitive)) {
            if (relativePath) {
                *relativePath = absolutePath.mid(folderPath.length());
                relativePath->chop(1); // we added a '/' above
            }
            return folder;
        }
    }

    if (relativePath)
        relativePath->clear();
    return 0;
}

QStringList FolderMan::findFileInLocalFolders(const QString &relPath, const AccountPtr acc)
{
    QStringList re;

    // We'll be comparing against Folder::remotePath which always starts with /
    QString serverPath = relPath;
    if (!serverPath.startsWith('/'))
        serverPath.prepend('/');

    foreach (Folder *folder, this->map().values()) {
        if (acc != 0 && folder->accountState()->account() != acc) {
            continue;
        }
        if (!serverPath.startsWith(folder->remotePath()))
            continue;

        QString path = folder->cleanPath() + '/';
        path += serverPath.midRef(folder->remotePathTrailingSlash().length());
        if (QFile::exists(path)) {
            re.append(path);
        }
    }
    return re;
}

void FolderMan::removeFolder(Folder *f)
{
    if (!f) {
        qCCritical(lcFolderMan) << "Can not remove null folder";
        return;
    }

    qCInfo(lcFolderMan) << "Removing " << f->alias();

    const bool currentlyRunning = f->isSyncRunning();
    if (currentlyRunning) {
        // abort the sync now
        f->slotTerminateSync();
    }

    if (_scheduledFolders.removeAll(f) > 0) {
        emit scheduleQueueChanged();
    }

    f->setSyncPaused(true);
    f->wipeForRemoval();

    // remove the folder configuration
    f->removeFromSettings();

    unloadFolder(f);
    if (currentlyRunning) {
        // We want to schedule the next folder once this is done
        connect(f, &Folder::syncFinished,
            this, &FolderMan::slotFolderSyncFinished);
        // Let the folder delete itself when done.
        connect(f, &Folder::syncFinished, f, &QObject::deleteLater);
    } else {
        delete f;
    }

    _navigationPaneHelper.scheduleUpdateCloudStorageRegistry();

    emit folderListChanged(_folderMap);
}

QString FolderMan::getBackupName(QString fullPathName) const
{
    if (fullPathName.endsWith("/"))
        fullPathName.chop(1);

    if (fullPathName.isEmpty())
        return QString();

    QString newName = fullPathName + tr(" (backup)");
    QFileInfo fi(newName);
    int cnt = 2;
    do {
        if (fi.exists()) {
            newName = fullPathName + tr(" (backup %1)").arg(cnt++);
            fi.setFile(newName);
        }
    } while (fi.exists());

    return newName;
}

bool FolderMan::startFromScratch(const QString &localFolder)
{
    if (localFolder.isEmpty()) {
        return false;
    }

    QFileInfo fi(localFolder);
    QDir parentDir(fi.dir());
    QString folderName = fi.fileName();

    // Adjust for case where localFolder ends with a /
    if (fi.isDir()) {
        folderName = parentDir.dirName();
        parentDir.cdUp();
    }

    if (fi.exists()) {
        // It exists, but is empty -> just reuse it.
        if (fi.isDir() && fi.dir().count() == 0) {
            qCDebug(lcFolderMan) << "startFromScratch: Directory is empty!";
            return true;
        }
        // Disconnect the socket api from the database to avoid that locking of the
        // db file does not allow to move this dir.
        Folder *f = folderForPath(localFolder);
        if (f) {
            if (localFolder.startsWith(f->path())) {
                _socketApi->slotUnregisterPath(f->alias());
            }
            f->journalDb()->close();
            f->slotTerminateSync(); // Normally it should not be running, but viel hilft viel
        }

        // Make a backup of the folder/file.
        QString newName = getBackupName(parentDir.absoluteFilePath(folderName));
        QString renameError;
        if (!FileSystem::rename(fi.absoluteFilePath(), newName, &renameError)) {
            qCWarning(lcFolderMan) << "startFromScratch: Could not rename" << fi.absoluteFilePath()
                                   << "to" << newName << "error:" << renameError;
            return false;
        }
    }

    if (!parentDir.mkdir(fi.absoluteFilePath())) {
        qCWarning(lcFolderMan) << "startFromScratch: Could not mkdir" << fi.absoluteFilePath();
        return false;
    }

    return true;
}

void FolderMan::setDirtyProxy()
{
    foreach (Folder *f, _folderMap.values()) {
        if (f) {
            if (f->accountState() && f->accountState()->account()
                && f->accountState()->account()->networkAccessManager()) {
                // Need to do this so we do not use the old determined system proxy
                f->accountState()->account()->networkAccessManager()->setProxy(
                    QNetworkProxy(QNetworkProxy::DefaultProxy));
            }
        }
    }
}

void FolderMan::setDirtyNetworkLimits()
{
    foreach (Folder *f, _folderMap.values()) {
        // set only in busy folders. Otherwise they read the config anyway.
        if (f && f->isBusy()) {
            f->setDirtyNetworkLimits();
        }
    }
}

void FolderMan::trayOverallStatus(const QList<Folder *> &folders,
    SyncResult::Status *status, bool *unresolvedConflicts)
{
    *status = SyncResult::Undefined;
    *unresolvedConflicts = false;

    int cnt = folders.count();

    // if one folder: show the state of the one folder.
    // if more folders:
    // if one of them has an error -> show error
    // if one is paused, but others ok, show ok
    // do not show "problem" in the tray
    //
    if (cnt == 1) {
        Folder *folder = folders.at(0);
        if (folder) {
            auto syncResult = folder->syncResult();
            if (folder->syncPaused()) {
                *status = SyncResult::Paused;
            } else {
                SyncResult::Status syncStatus = syncResult.status();
                switch (syncStatus) {
                case SyncResult::Undefined:
                    *status = SyncResult::Error;
                    break;
                case SyncResult::Problem: // don't show the problem icon in tray.
                    *status = SyncResult::Success;
                    break;
                default:
                    *status = syncStatus;
                    break;
                }
            }
            *unresolvedConflicts = syncResult.hasUnresolvedConflicts();
        }
    } else {
        int errorsSeen = 0;
        int goodSeen = 0;
        int abortOrPausedSeen = 0;
        int runSeen = 0;
        int various = 0;

        foreach (Folder *folder, folders) {
            SyncResult folderResult = folder->syncResult();
            if (folder->syncPaused()) {
                abortOrPausedSeen++;
            } else {
                SyncResult::Status syncStatus = folderResult.status();

                switch (syncStatus) {
                case SyncResult::Undefined:
                case SyncResult::NotYetStarted:
                    various++;
                    break;
                case SyncResult::SyncPrepare:
                case SyncResult::SyncRunning:
                    runSeen++;
                    break;
                case SyncResult::Problem: // don't show the problem icon in tray.
                case SyncResult::Success:
                    goodSeen++;
                    break;
                case SyncResult::Error:
                case SyncResult::SetupError:
                    errorsSeen++;
                    break;
                case SyncResult::SyncAbortRequested:
                case SyncResult::Paused:
                    abortOrPausedSeen++;
                    // no default case on purpose, check compiler warnings
                }
            }
            if (folderResult.hasUnresolvedConflicts())
                *unresolvedConflicts = true;
        }
        if (errorsSeen > 0) {
            *status = SyncResult::Error;
        } else if (abortOrPausedSeen > 0 && abortOrPausedSeen == cnt) {
            // only if all folders are paused
            *status = SyncResult::Paused;
        } else if (runSeen > 0) {
            *status = SyncResult::SyncRunning;
        } else if (goodSeen > 0) {
            *status = SyncResult::Success;
        }
    }
}

QString FolderMan::trayTooltipStatusString(
    SyncResult::Status syncStatus, bool hasUnresolvedConflicts, bool paused)
{
    QString folderMessage;
    switch (syncStatus) {
    case SyncResult::Undefined:
        folderMessage = tr("Undefined State.");
        break;
    case SyncResult::NotYetStarted:
        folderMessage = tr("Waiting to start syncing.");
        break;
    case SyncResult::SyncPrepare:
        folderMessage = tr("Preparing for sync.");
        break;
    case SyncResult::SyncRunning:
        folderMessage = tr("Sync is running.");
        break;
    case SyncResult::Success:
    case SyncResult::Problem:
        if (hasUnresolvedConflicts) {
            folderMessage = tr("Sync was successful, unresolved conflicts.");
        } else {
            folderMessage = tr("Last Sync was successful.");
        }
        break;
    case SyncResult::Error:
        break;
    case SyncResult::SetupError:
        folderMessage = tr("Setup Error.");
        break;
    case SyncResult::SyncAbortRequested:
        folderMessage = tr("User Abort.");
        break;
    case SyncResult::Paused:
        folderMessage = tr("Sync is paused.");
        break;
        // no default case on purpose, check compiler warnings
    }
    if (paused) {
        // sync is disabled.
        folderMessage = tr("%1 (Sync is paused)").arg(folderMessage);
    }
    return folderMessage;
}

static QString checkPathValidityRecursive(const QString &path)
{
    if (path.isEmpty()) {
        return FolderMan::tr("No valid folder selected!");
    }

    QFileInfo selFile(path);

    if (!selFile.exists()) {
        QString parentPath = selFile.dir().path();
        if (parentPath != path)
            return checkPathValidityRecursive(parentPath);
        return FolderMan::tr("The selected path does not exist!");
    }

    if (!selFile.isDir()) {
        return FolderMan::tr("The selected path is not a folder!");
    }

    if (!selFile.isWritable()) {
        return FolderMan::tr("You have no permission to write to the selected folder!");
    }
    return QString();
}

// QFileInfo::canonicalPath returns an empty string if the file does not exist.
// This function also works with files that does not exist and resolve the symlinks in the
// parent directories.
static QString canonicalPath(const QString &path)
{
    QFileInfo selFile(path);
    if (!selFile.exists()) {
        const auto parentPath = selFile.dir().path();

        // It's possible for the parentPath to match the path
        // (possibly we've arrived at a non-existant drive root on Windows)
        // and recursing would be fatal.
        if (parentPath == path) {
            return path;
        }

        return canonicalPath(parentPath) + '/' + selFile.fileName();
    }
    return selFile.canonicalFilePath();
}

QString FolderMan::checkPathValidityForNewFolder(const QString &path, const QUrl &serverUrl) const
{
    QString recursiveValidity = checkPathValidityRecursive(path);
    if (!recursiveValidity.isEmpty())
        return recursiveValidity;

    // check if the local directory isn't used yet in another ownCloud sync
    Qt::CaseSensitivity cs = Qt::CaseSensitive;
    if (Utility::fsCasePreserving()) {
        cs = Qt::CaseInsensitive;
    }

    const QString userDir = QDir::cleanPath(canonicalPath(path)) + '/';
    for (auto i = _folderMap.constBegin(); i != _folderMap.constEnd(); ++i) {
        Folder *f = static_cast<Folder *>(i.value());
        QString folderDir = QDir::cleanPath(canonicalPath(f->path())) + '/';

        bool differentPaths = QString::compare(folderDir, userDir, cs) != 0;
        if (differentPaths && folderDir.startsWith(userDir, cs)) {
            return tr("The local folder %1 already contains a folder used in a folder sync connection. "
                      "Please pick another one!")
                .arg(QDir::toNativeSeparators(path));
        }

        if (differentPaths && userDir.startsWith(folderDir, cs)) {
            return tr("The local folder %1 is already contained in a folder used in a folder sync connection. "
                      "Please pick another one!")
                .arg(QDir::toNativeSeparators(path));
        }

        // if both pathes are equal, the server url needs to be different
        // otherwise it would mean that a new connection from the same local folder
        // to the same account is added which is not wanted. The account must differ.
        if (serverUrl.isValid() && !differentPaths) {
            QUrl folderUrl = f->accountState()->account()->url();
            QString user = f->accountState()->account()->credentials()->user();
            folderUrl.setUserName(user);

            if (serverUrl == folderUrl) {
                return tr("There is already a sync from the server to this local folder. "
                          "Please pick another local folder!");
            }
        }
    }

    return QString();
}

QString FolderMan::findGoodPathForNewSyncFolder(const QString &basePath, const QUrl &serverUrl) const
{
    QString folder = basePath;

    // If the parent folder is a sync folder or contained in one, we can't
    // possibly find a valid sync folder inside it.
    // Example: Someone syncs their home directory. Then ~/foobar is not
    // going to be an acceptable sync folder path for any value of foobar.
    QString parentFolder = QFileInfo(folder).dir().canonicalPath();
    if (FolderMan::instance()->folderForPath(parentFolder)) {
        // Any path with that parent is going to be unacceptable,
        // so just keep it as-is.
        return basePath;
    }

    int attempt = 1;
    forever {
        const bool isGood =
            !QFileInfo(folder).exists()
            && FolderMan::instance()->checkPathValidityForNewFolder(folder, serverUrl).isEmpty();
        if (isGood) {
            break;
        }

        // Count attempts and give up eventually
        attempt++;
        if (attempt > 100) {
            return basePath;
        }

        folder = basePath + QString::number(attempt);
    }

    return folder;
}

bool FolderMan::ignoreHiddenFiles() const
{
    if (_folderMap.empty()) {
        return true;
    }
    return _folderMap.begin().value()->ignoreHiddenFiles();
}

void FolderMan::setIgnoreHiddenFiles(bool ignore)
{
    // Note that the setting will revert to 'true' if all folders
    // are deleted...
    foreach (Folder *folder, _folderMap) {
        folder->setIgnoreHiddenFiles(ignore);
        folder->saveToSettings();
    }
}

QQueue<Folder *> FolderMan::scheduleQueue() const
{
    return _scheduledFolders;
}

Folder *FolderMan::currentSyncFolder() const
{
    return _currentSyncFolder;
}

void FolderMan::restartApplication()
{
    if (Utility::isLinux()) {
        // restart:
        qCInfo(lcFolderMan) << "Restarting application NOW, PID" << qApp->applicationPid() << "is ending.";
        qApp->quit();
        QStringList args = qApp->arguments();
        QString prg = args.takeFirst();

        QProcess::startDetached(prg, args);
    } else {
        qCDebug(lcFolderMan) << "On this platform we do not restart.";
    }
}

} // namespace OCC
