#include "./alpmdatabase.h"
#include "./upgradelookup.h"
#include "./alpmpackage.h"
#include "./utilities.h"

#include <c++utilities/misc/memory.h>

#include <KTar>
#include <KArchiveDirectory>

#include <QList>
#include <QJsonObject>
#include <QtConcurrent>

#include <iostream>

using namespace std;

namespace RepoIndex {

using namespace Utilities;

/*!
 * \class AlpmDatabase
 * \brief The AlpmDatabase class wraps an ALPM data base struct and holds additional meta information.
 *
 * All packages returned by the AlpmDatabase class are AlpmPackage instances.
 */

class LoadPackage
{
public:
    LoadPackage(AlpmDatabase *database, PackageOrigin origin) :
        m_db(database),
        m_origin(origin)
    {}

    void operator()(const QPair<QString, QList<QByteArray> > &description)
    {
        m_db->addPackageFromDescription(description.first, description.second, m_origin);
    }

private:
    AlpmDatabase *const m_db;
    const PackageOrigin m_origin;
};

void AlpmDatabase::loadDescriptions(QList<QPair<QString, QList<QByteArray> > > &descriptions)
{
    QFileInfo pathInfo(databasePath());
    if(pathInfo.isDir()) {
        static const QStringList relevantFiles = QStringList() << QStringLiteral("desc") << QStringLiteral("files");
        QDir dbDir(databasePath());
        QStringList pkgDirNames = dbDir.entryList(QDir::Dirs | QDir::Readable | QDir::Executable | QDir::NoDotAndDotDot);
        descriptions.reserve(pkgDirNames.size());
        for(QString &pkgDirName : pkgDirNames) {
            if(dbDir.cd(pkgDirName)) {
                Utilities::stripVersion(pkgDirName);
                const QStringList descFileNames = dbDir.entryList(relevantFiles, QDir::Files | QDir::Readable | QDir::NoDotAndDotDot);
                QList<QByteArray> descData;
                descData.reserve(descFileNames.size());
                for(const QString &descFileName : descFileNames) {
                    QFile descFile(dbDir.absoluteFilePath(descFileName));
                    if(descFile.open(QFile::ReadOnly)) {
                        descData << descFile.readAll();
                    } else {
                        // TODO: error handling (can't open pkg file)
                    }
                }
                if(!descData.isEmpty()) {
                    descriptions << qMakePair(pkgDirName, descData);
                }
                dbDir.cdUp();
            } else {
                // TODO: error handling (can't enter pkg dir)
            }
        }
    } else if(pathInfo.isFile()) {
        KTar tar(databasePath());
        const KArchiveDirectory *dbDir;
        if(tar.open(QIODevice::ReadOnly) && (dbDir = tar.directory())) {
            QStringList pkgDirNames = dbDir->entries();
            descriptions.reserve(pkgDirNames.size());
            for(QString &pkgDirName : pkgDirNames) {
                if(const auto *pkgEntry = dbDir->entry(pkgDirName)) {
                    if(pkgEntry->isDirectory()) {
                        Utilities::stripVersion(pkgDirName);
                        const auto *pkgDir = static_cast<const KArchiveDirectory *>(pkgEntry);
                        const QStringList descFileNames = pkgDir->entries();
                        QList<QByteArray> descData;
                        descData.reserve(descFileNames.size());
                        for(const QString &descFileName : descFileNames) {
                            if(const auto *descEntry = pkgDir->entry(descFileName)) {
                                if(descEntry->isFile()) {
                                    descData << static_cast<const KArchiveFile *>(descEntry)->data();
                                } else {
                                    // there shouldn't be any subdirs
                                }
                            }
                        }
                        if(!descData.isEmpty()) {
                            descriptions << qMakePair(pkgDirName, descData);
                        }
                    } else {
                        // there shouldn't be any files
                    }
                }
            }
        } else {
            // TODO: error handling (can't open sync db file)
        }
    } else {
        // TODO: error handling
    }
}

AlpmPackageLoader::AlpmPackageLoader(AlpmDatabase *repository, PackageOrigin origin)
{
    repository->loadDescriptions(m_descriptions);
    m_future = QtConcurrent::map(m_descriptions, LoadPackage(repository, origin));
}

/*!
 * \brief Creates a new instance wrapping the specified database struct.
 */
AlpmDatabase::AlpmDatabase(const QString &name, const QString &dbPath, RepositoryUsage usage, SignatureLevel sigLevel, uint32 index, QObject *parent) :
    Repository(name, index, parent),
    m_dbPath(dbPath)
{
    m_usage = usage;
    m_sigLevel = sigLevel;
}

AlpmPackageLoader *AlpmDatabase::init()
{
    // set description, determine origin
    PackageOrigin origin;
    if(m_name.compare(QLatin1String("local"), Qt::CaseInsensitive) == 0) {
        m_description = QStringLiteral("The local database");
        origin = PackageOrigin::LocalDb;
    } else {
        if((m_usage & RepositoryUsage::Sync) || (m_usage & RepositoryUsage::Install) || (m_usage & RepositoryUsage::Upgrade)) {
            m_description = QStringLiteral("Sync database »%1«").arg(m_name);
        } else {
            m_description = QStringLiteral("Database »%1«").arg(m_name);
        }
        origin = PackageOrigin::SyncDb;
    }

    // initialization of packages is done concurrently via AlpmPackageLoader: ~ 4 sec
    return new AlpmPackageLoader(this, origin);

    // without concurrency: ~ 12 sec
    //QList<QPair<QString, QList<QByteArray> > > descriptions;
    //loadDescriptions(descriptions);
    //for(const auto &description : descriptions) {
    //    addPackageFromDescription(description.first, description.second, origin);
    //}
    //return nullptr;
}

RepositoryType AlpmDatabase::type() const
{
    return RepositoryType::AlpmDatabase;
}

PackageDetailAvailability AlpmDatabase::requestsRequired(PackageDetail packageDetail) const
{
    switch(packageDetail) {
    case PackageDetail::Basics:
    case PackageDetail::Dependencies:
    case PackageDetail::PackageInfo:
    case PackageDetail::AllAvailable:
        return PackageDetailAvailability::Immediately;
    default:
        return PackageDetailAvailability::Never;
    }
}

std::unique_ptr<Package> AlpmDatabase::emptyPackage()
{
    return make_unique<AlpmPackage>(this);
}

} // namespace Alpm