#ifndef PACKAGEMANAGEMENT_PACKAGESOURCE_H
#define PACKAGEMANAGEMENT_PACKAGESOURCE_H

#include "./package.h"

#include <QObject>
#include <QFuture>
#include <QJsonObject>
#include <QReadWriteLock>

#include <memory>
#include <functional>

QT_FORWARD_DECLARE_CLASS(QNetworkReply)

namespace RepoIndex {

class UpgradeLookupResults;

class Reply : public QObject
{
    Q_OBJECT
public:
    Reply(QNetworkReply *networkReply);
    Reply(const QList<QNetworkReply *> networkReplies);
    const QString &error() const;

Q_SIGNALS:
    void resultsAvailable();

private Q_SLOTS:
    void replyFinished();

private:
    virtual void processData(QNetworkReply *reply) = 0;

protected:
    QList<QNetworkReply *> m_networkReplies;
    unsigned int m_remainingReplies;
    QString m_error;
};

inline const QString &Reply::error() const
{
    return m_error;
}

class PackageReply : public Reply
{
    Q_OBJECT
public:
    PackageReply(QNetworkReply *networkReply, const QStringList &requestedPackages, Repository *repo);
    PackageReply(const QList<QNetworkReply *> &networkReplies, const QStringList &requestedPackages, Repository *repo);
    const QStringList &requestedPackages() const;
    Repository *repository();
    const Repository *repository() const;

protected:
    QStringList m_requestedPackages;
    Repository *m_repo;
};

inline PackageReply::PackageReply(QNetworkReply *networkReply, const QStringList &requestedPackages, Repository *repo) :
    Reply(networkReply),
    m_requestedPackages(requestedPackages),
    m_repo(repo)
{}

inline PackageReply::PackageReply(const QList<QNetworkReply *> &networkReplies, const QStringList &requestedPackages, Repository *repo) :
    Reply(networkReplies),
    m_requestedPackages(requestedPackages),
    m_repo(repo)
{}

inline const QStringList &PackageReply::requestedPackages() const
{
    return m_requestedPackages;
}

inline Repository *PackageReply::repository()
{
    return m_repo;
}

inline const Repository *PackageReply::repository() const
{
    return m_repo;
}

class SuggestionsReply : public Reply
{
    Q_OBJECT
public:
    SuggestionsReply(QNetworkReply *networkReply, const QString &term, Repository *repo);
    const Repository *repository() const;
    QJsonObject suggestions() const;

protected:
    QString m_term;
    Repository *m_repo;
};

inline SuggestionsReply::SuggestionsReply(QNetworkReply *networkReply, const QString &term, Repository *repo) :
    Reply(networkReply),
    m_term(term),
    m_repo(repo)
{}

inline const Repository *SuggestionsReply::repository() const
{
    return m_repo;
}

class PackageLoader
{
public:
    QFuture<void> &future();
    virtual ~PackageLoader();

protected:
    PackageLoader();
    QMutex m_mutex;
    QFuture<void> m_future;
};

inline PackageLoader::PackageLoader()
{}

inline PackageLoader::~PackageLoader()
{}

inline QFuture<void> &PackageLoader::future()
{
    return m_future;
}

/*!
 * \brief The RepositoryType enum specifies the type of a repository object.
 */
enum class RepositoryType
{
    AlpmDatabase, /*! The repository is an AlpmDataBase instance. */
    UserRepository, /*! The repository is a UserRepository instance. */
    Other /*! The repository type is unknown. */
};

/*!
 * \brief The PackageDetail enum is used to refer to some kind of information about a package.
 */
enum class PackageDetail
{
    Basics, /*! Basic information about the package such as knowing it exists, its name, version and description. */
    Dependencies, /*! The runtime dependencies of the package. */
    SourceInfo, /*! The source info such as make dependencies of the package. */
    PackageInfo, /*! Information related to a specific package (pkg-file). */
    AllAvailable /*! All available package details. */
};

/*!
 * \brief The PackageDetailAvailability enum describes when some kind of information about a package
 *        becomes available.
 */
enum class PackageDetailAvailability
{
    Never, /*! The information is not available and can't be requested. */
    Immediately, /*! The information is available immediately after the repository object has been constructed. */
    Request, /*! The information is available after the requestPackageInfo() method has been called for the package. */
    FullRequest /*! The information is available after the requestFullPackageInfo() method has been called for the package. */
};

/*!
 * \brief The RepositoryUsage enum specifies the usage of a repository.
 */
enum class RepositoryUsage {
    None = 0,
    Sync = 1, /*! The repository is used when synchronizing. */
    Search = (1 << 1), /*! The repository is used when searching. */
    Install = (1 << 2), /*! The repository is used to install packages. */
    Upgrade = (1 << 3), /*! The repository is used to upgrade packages. */
    All = (1 << 4) - 1, /*! The reposiotry is used for everything. */
};

constexpr bool operator &(RepositoryUsage lhs, RepositoryUsage rhs)
{
    return (static_cast<int>(lhs) & static_cast<int>(rhs)) != 0;
}

inline RepositoryUsage &operator |=(RepositoryUsage &lhs, RepositoryUsage rhs)
{
    lhs = static_cast<RepositoryUsage>(static_cast<int>(lhs) | static_cast<int>(rhs));
    return lhs;
}

class Repository : public QObject
{
    Q_OBJECT
public:
    ~Repository();

    virtual RepositoryType type() const = 0;

    // general meta data
    bool isBusy() const;
    std::uint32_t index() const;
    const QString &name() const;
    const QString &description() const;
    const std::map<QString, std::unique_ptr<Package> > &packages() const;
    std::map<QString, std::unique_ptr<Package> > &packages();
    const QStringList packageNames() const;
    RepositoryUsage usage() const;
    bool isSourceOnly() const;
    bool isPackageOnly() const;
    std::map<QString, QList<Package *> > &groups();
    const std::map<QString, QList<Package *> > &groups() const;
    Q_SLOT void updateGroups();
    const QStringList &serverUrls() const;
    QStringList &serverUrls();
    SignatureLevel sigLevel() const;
    void setSigLevel(SignatureLevel sigLevel);

    // gathering data
    Q_SLOT PackageLoader *init();
    void initAsSoonAsPossible();
    void asSoonAsPossible(std::function<void(void)> operation);
    virtual PackageLoader *internalInit();
    virtual PackageDetailAvailability requestsRequired(PackageDetail packageDetail = PackageDetail::Basics) const;
    virtual SuggestionsReply *requestSuggestions(const QString &phrase);
    virtual PackageReply *requestPackageInfo(const QStringList &packageNames, bool forceUpdate = false);
    virtual PackageReply *requestFullPackageInfo(const QStringList &packageNames, bool forceUpdate = false);

    // package search
    const Package *packageByName(const QString &name) const;
    Package *packageByName(const QString &name);
    const Package *packageProviding(const Dependency &dependency) const;
    Package *packageProviding(const Dependency &dependency);
    QList<const Package *> packagesProviding(const Dependency &dependency) const;
    QList<Package *> packageByFilter(std::function<bool (const Package *)> pred);
    QFuture<void> computeRequiredBy(const QList<Repository *> &relevantRepositories, bool forceUpdate = false);
    QJsonObject suggestions(const QString &term) const;

    // upgrade lookup
    const QList<Repository *> &upgradeSources() const;
    QList<Repository *> &upgradeSources();
    QJsonArray upgradeSourcesJsonArray() const;
    void checkForUpgrades(UpgradeLookupResults &results) const;
    void checkForUpgrades(UpgradeLookupResults &results, const QList<Repository *> &upgradeSources) const;

    // build system
    const QString &sourcesDirectory() const;
    void setSourcesDirectory(const QString &dir);
    const QString &packagesDirectory() const;
    void setPackagesDirectory(const QString &dir);

    // JSON serialization
    QJsonArray packageNamesJsonArray() const;
    QJsonObject packagesObjectSkeleton() const;
    QJsonObject basicInfo(bool includeName = false) const;
    QJsonObject groupInfo() const;

    // caching
    bool isCachingUseful() const;
    void writeToCacheStream(QDataStream &out);
    void restoreFromCacheStream(QDataStream &in, bool skipOutdated = true);
    virtual void writeSpecificCacheHeader(QDataStream &out);
    virtual std::unique_ptr<Package> emptyPackage();
    virtual void restoreSpecificCacheHeader(QDataStream &in);
    CppUtilities::TimeSpan maxPackageAge() const;
    void setMaxPackageAge(CppUtilities::TimeSpan maxPackageAge);
    void cleanOutdatedPackages();
    bool hasOutdatedPackages();
    void wipePackages();

    // parsing src/pkg info
    static void parsePkgInfo(const QByteArray &pkgInfo, QString &name, QList<QPair<QString, QString> > packageInfo);
    static void parseDescriptions(const QList<QByteArray> &descriptions, QString &name, QList<QPair<QString, QStringList> > &fields);
    QList<Package *> addPackagesFromSrcInfo(const QByteArray &srcInfo, CppUtilities::DateTime timeStamp);
    Package *addPackageFromDescription(QString name, const QList<QByteArray> &descriptions, PackageOrigin origin, CppUtilities::DateTime timeStamp);

    // thread synchronization
    QReadWriteLock *lock() const;

    static const std::uint32_t invalidIndex = static_cast<std::uint32_t>(-1);

Q_SIGNALS:
    /*!
     * \brief Emitted after initialization has finished.
     */
    void initialized();

    /*!
     * \brief Emitted after required-by computation has finished.
     */
    void requiredByComputed();

    /*!
     * \brief Indicates the repository is not busy anymore; emitted after either initialization or required-by computation has finished.
     */
    void available();

protected Q_SLOTS:
    void addBusyFlag();
    void removeBusyFlag();

private Q_SLOTS:
    void discardPackageLoader();

protected:
    explicit Repository(const QString &name, std::uint32_t index = invalidIndex, QObject *parent = nullptr);

    std::uint32_t m_index;
    QString m_name;
    QString m_description;
    std::map<QString, std::unique_ptr<Package> > m_packages;
    CppUtilities::TimeSpan m_maxPackageAge;
    RepositoryUsage m_usage;
    std::map<QString, QList<Package *> > m_groups;
    QStringList m_serverUrls;
    SignatureLevel m_sigLevel;
    QList<Repository *> m_upgradeSources;
    QString m_srcDir;
    QString m_pkgDir;
    QAtomicInteger<std::uint8_t> m_isBusy;
    std::unique_ptr<PackageLoader> m_loader;

private:
    QReadWriteLock m_lock;
};

/*!
 * \brief Returns the suggestions.
 */
inline QJsonObject SuggestionsReply::suggestions() const
{
    return m_repo->suggestions(m_term);
}

/*!
 * \brief Returns an indication whether the repository is busy (either initializing or computing required-by).
 *
 * In this case the repository shouldn't be touched until the available() signal is emitted.
 *
 * \remarks This method is thread-safe.
 */
inline bool Repository::isBusy() const
{
    return m_isBusy.load() != 0;
}

/*!
 * \brief Returns the index of the repository.
 *
 * The index is used to sort the repositories by their occurrence the configuration files.
 */
inline std::uint32_t Repository::index() const
{
    return m_index;
}

/*!
 * \brief Returns the name.
 */
inline const QString &Repository::name() const
{
    return m_name;
}

/*!
 * \brief Returns the description.
 */
inline const QString &Repository::description() const
{
    return m_description;
}

/*!
 * \brief Returns whether the repository only has sources but no built packages.
 */
inline bool Repository::isSourceOnly() const
{
    return requestsRequired(PackageDetail::PackageInfo) == PackageDetailAvailability::Never;
}

/*!
 * \brief Returns whether the repository only has built packages but no sources.
 */
inline bool Repository::isPackageOnly() const
{
    return requestsRequired(PackageDetail::SourceInfo) == PackageDetailAvailability::Never;
}

/*!
 * \brief Returns the packages.
 */
inline const std::map<QString, std::unique_ptr<Package> > &Repository::packages() const
{
    return m_packages;
}

/*!
 * \brief Returns the packages.
 */
inline std::map<QString, std::unique_ptr<Package> > &Repository::packages()
{
    return m_packages;
}

/*!
 * \brief Returns the package with the specified \a name or nullptr if the package can not be found.
 * \remarks Ownership remains by this instance.
 */
inline const Package *Repository::packageByName(const QString &name) const
{
    try {
        return m_packages.at(name).get();
    } catch(const std::out_of_range &) {
        return nullptr;
    }
}

/*!
 * \brief Returns the package with the specified \a name or nullptr if the package can not be found.
 * \remarks Ownership remains by this instance.
 */
inline Package *Repository::packageByName(const QString &name)
{
    try {
        return m_packages.at(name).get();
    } catch(const std::out_of_range &) {
        return nullptr;
    }
}

/*!
 * \brief Returns the operations the repository is used for.
 */
inline RepositoryUsage Repository::usage() const
{
    return m_usage;
}

/*!
 * \brief Returns the groups the packages of the repository belong to.
 */
inline std::map<QString, QList<Package *> > &Repository::groups()
{
    return m_groups;
}


/*!
 * \brief Returns the groups the packages of the repository belong to.
 */
inline const std::map<QString, QList<Package *> > &Repository::groups() const
{
    return m_groups;
}

/*!
 * \brief Returns the server URLs.
 */
inline const QStringList &Repository::serverUrls() const
{
    return m_serverUrls;
}

/*!
 * \brief Returns the server URLs.
 * \remarks This non-const version is used by the manager to add the servers.
 */
inline QStringList &Repository::serverUrls()
{
    return m_serverUrls;
}

/*!
 * \brief Returns the signature level of the database.
 */
inline SignatureLevel Repository::sigLevel() const
{
    return m_sigLevel;
}

/*!
 * \brief Sets the signature level.
 */
inline void Repository::setSigLevel(SignatureLevel sigLevel)
{
    m_sigLevel = sigLevel;
}

/*!
 * \brief Returns the upgrade sources for the repository.
 */
inline const QList<Repository *> &Repository::upgradeSources() const
{
    return m_upgradeSources;
}

/*!
 * \brief Returns the upgrade sources for the repository.
 * \remarks This non-const version is used by the manager to add upgrade sources.
 */
inline QList<Repository *> &Repository::upgradeSources()
{
    return m_upgradeSources;
}

inline void Repository::checkForUpgrades(UpgradeLookupResults &results) const
{
    checkForUpgrades(results, upgradeSources());
}

/*!
 * \brief Returns the path of the local sources directory.
 */
inline const QString &Repository::sourcesDirectory() const
{
    return m_srcDir;
}

/*!
 * \brief Sets the path of the local sources directory.
 */
inline void Repository::setSourcesDirectory(const QString &dir)
{
    m_srcDir = dir;
}

/*!
 * \brief Returns the path of the local packages directory.
 */
inline const QString &Repository::packagesDirectory() const
{
    return m_pkgDir;
}

/*!
 * \brief Sets the path of the local packages directory.
 */
inline void Repository::setPackagesDirectory(const QString &dir)
{
    m_pkgDir = dir;
}

/*!
 * \brief Returns whether caching this repository is useful.
 */
inline bool Repository::isCachingUseful() const
{
    switch(requestsRequired(PackageDetail::AllAvailable)) {
    case PackageDetailAvailability::Request:
    case PackageDetailAvailability::FullRequest:
        return true;
    default:
        return false;
    }
}

/*!
 * \brief Returns the max package age.
 * \sa setMaxPackageAge()
 */
inline CppUtilities::TimeSpan Repository::maxPackageAge() const
{
    return m_maxPackageAge;
}

/*!
 * \brief Sets the max package age which is used by the cleanOutdatedPackages() and
 *        the hasOutdatedPackages() method.
 */
inline void Repository::setMaxPackageAge(CppUtilities::TimeSpan maxPackageAge)
{
    m_maxPackageAge = maxPackageAge;
}

/*!
 * \brief Wipes all packages.
 */
inline void Repository::wipePackages()
{
    m_packages.clear();
    m_groups.clear();
}

/*!
 * \brief Returns the read-write lock used for thread-synchronization.
 */
inline QReadWriteLock *Repository::lock() const
{
    return const_cast<QReadWriteLock *>(&m_lock);
}

} // namespace PackageManagement

#endif // PACKAGEMANAGEMENT_PACKAGESOURCE_H