#ifndef PACKAGEMANAGEMENT_UPDATELOOKUP_H
#define PACKAGEMANAGEMENT_UPDATELOOKUP_H

#include "./package.h"

#include <QObject>
#include <QJsonObject>
#include <QJsonArray>
#include <QFutureWatcher>

namespace RepoIndex {

class Manager;
class UpgradeLookup;
class UpgradeLookupProcess;
class PackageReply;

class UpgradeResult
{
public:
    UpgradeResult(const Package *package, const QString &currentVersion);
    const Package *package;
    QString currentVersion;
    QJsonObject toJson() const;
};

/*!
 * \brief Constructs a new upgrade result.
 */
inline UpgradeResult::UpgradeResult(const Package *package, const QString &previousVersion) :
    package(package),
    currentVersion(previousVersion)
{}

class UpgradeLookupResults
{
public:
    UpgradeLookupResults();

    /*!
     * \brief Indicates that there are no upgrade sources available.
     */
    bool noSources;

    /*!
     * \brief Packages providing a software upgrade (new version).
     */
    QList<UpgradeResult> newVersions;

    /*!
     * \brief Package upgrades only (new release).
     */
    QList<UpgradeResult> newReleases;

    /*!
     * \brief Downgrades (older version in sync db).
     */
    QList<UpgradeResult> downgrades;

    /*!
     * \brief Orphaned packages (could not be found in any of the sync dbs).
     */
    QSet<const Package *> orphaned;

    /*!
     * \brief Warnings occured when checking for updates.
     */
    QStringList warnings;

    /*!
     * \brief Errors occured when checking for updates.
     */
    QStringList errors;
};

/*!
 * \brief Constructs new update lookup results.
 */
inline UpgradeLookupResults::UpgradeLookupResults() :
    noSources(false)
{}

class UpgradeLookupProcess : public QObject
{
    Q_OBJECT
public:
    explicit UpgradeLookupProcess(UpgradeLookup *upgradeLookup, Repository *upgradeSource);
    const UpgradeLookupResults &results() const;

Q_SIGNALS:
    void finished();

private Q_SLOTS:
    void requestSources();
    void sourceReady();
    void checkUpgrades();

private:
    bool ensureNotBusy();

    const Repository *m_toCheck;
    Repository *m_upgradeSource;
    PackageReply *m_reply;
    QFutureWatcher<void> *m_watcher;
    UpgradeLookupResults m_results;
};

class UpgradeLookup : public QObject
{
    Q_OBJECT
    friend class UpgradeLookupProcess;

public:
    const Repository *toCheck() const;

private Q_SLOTS:
    virtual void processFinished() = 0;

protected:
    explicit UpgradeLookup(QObject *parent = nullptr);


    Repository *m_toCheck;
    unsigned int m_remainingProcesses;
    bool m_firstFinished;
    QSet<const Package *> m_orphanedPackages;
};

/*!
 * \brief Returns the repository to be checked (if available; otherwise nullptr).
 */
inline const Repository *UpgradeLookup::toCheck() const
{
    return m_toCheck;
}

class UpgradeLookupJson : public UpgradeLookup
{
    Q_OBJECT
public:
    explicit UpgradeLookupJson(Manager &manager, const QJsonObject &request, QObject *parent = nullptr);
    const QJsonArray &errors() const;
    QJsonArray results() const;
    bool finished() const;

Q_SIGNALS:
    void resultsAvailable(const QJsonValue &what, const QJsonValue &id, const QJsonValue &value);

private Q_SLOTS:
    virtual void processFinished();

private:
    const QJsonObject m_request;
    QJsonArray m_warningsArray;
    QJsonArray m_errorsArray;
    QJsonArray m_softwareUpgradesArray;
    QJsonArray m_packageOnlyUpgradesArray;
    QJsonArray m_downgradesArray;
    QJsonArray m_orphanedPackagesArray;
};

inline const QJsonArray &UpgradeLookupJson::errors() const
{
    return m_errorsArray;
}

inline QJsonArray UpgradeLookupJson::results() const
{
    return QJsonArray(); // results are currently only returned by emitting resultsAvailable()
}

inline bool UpgradeLookupJson::finished() const
{
    return !m_remainingProcesses && m_errorsArray.isEmpty();
}

class UpgradeLookupCli : public UpgradeLookup
{
    Q_OBJECT
    friend class UpgradeLookupProcess;
public:
    explicit UpgradeLookupCli(Manager &manager, const std::string &repo, QObject *parent = nullptr);
    bool hasErrors() const;
    const Repository *toCheck() const;

private Q_SLOTS:
    void processFinished();

private:
    void printResults();

    QStringList m_warningsArray;
    QStringList m_errorsArray;
    QStringList m_softwareUpgradesArray;
    QStringList m_packageOnlyUpgradesArray;
    QStringList m_downgradesArray;
    QStringList m_orphanedPackagesArray;
};

inline bool UpgradeLookupCli::hasErrors() const
{
    return !m_errorsArray.isEmpty();
}


} // namespace PackageManagement

#endif // PACKAGEMANAGEMENT_UPDATELOOKUP_H