#ifndef SERVICE_H
#define SERVICE_H

#include <QList>
#include <QSharedPointer>
#include <QString>
#include <QEventLoop>
#include <QApplication>

#include "core_global.h"
#include "context.h"
#include "iservice.h"
#include "permissionevaluator.h"
#include "iimporter.h"
#include "iimportprogress.h"

template<class T>
class Service : public IService
{
public:
    explicit Service(QObject *parent = nullptr) :IService(parent) { }

    explicit Service(const QString &pluginId) {
        m_pluginId = pluginId;
    }

    QList<QSharedPointer<T> > all(const QString &where = "") {
        QList<QSharedPointer<T> > ret;

        if (!checkPermission(PERM_READ)) {
            return ret;
        }

        QScopedPointer<T> entity(new T());
        auto qEntity = dynamic_cast<QObject*>(entity.data());

        QStringList relations;
        QString sWhere = where.isEmpty() ? "" : "WHERE " + where;
        QSqlError err;

        if (qEntity
            && QMetaObject::invokeMethod(qEntity, "eagerLoad", Qt::DirectConnection, Q_RETURN_ARG(QStringList, relations))
            && !relations.isEmpty())
        {
            err = qx::dao::fetch_by_query_with_relation(relations, sWhere, ret);
        }
        else {
            err = qx::dao::fetch_by_query(sWhere, ret);
        }

        if (!err.isValid()) {
            return ret;
        } else {
            qDebug() << err.text();
            emit dbError(err.text());
        }

        return ret;
    }

    void save(QSharedPointer<T> entity, qx::QxSession* pSession = nullptr) {
        if (!checkPermission(PERM_ADD)) {
            return;
        }

        QScopedPointer<qx::QxSession> ptrSession;

        if (pSession == nullptr) {
            ptrSession.reset(new qx::QxSession());
            pSession = ptrSession.data();
        }

        addDateAndUser(entity, true);
        *pSession += qx::dao::insert_with_all_relation(entity, pSession->database());

        if (!pSession->isValid()) {
            qDebug() << pSession->firstError().text();
            emit dbError(pSession->firstError().text());
            emit dbErrorInsert(pSession->firstError().text());
            return;
        }

        emit dataChanged();
    }

    void update(QSharedPointer<T> entity, qx::QxSession* pSession = nullptr) {
        if (!checkPermission(PERM_EDIT)) {
            return;
        }

        QScopedPointer<qx::QxSession> ptrSession;

        if (pSession == nullptr) {
            ptrSession.reset(new qx::QxSession());
            pSession = ptrSession.data();
        }

        addDateAndUser(entity, false);

        *pSession += qx::dao::update_with_all_relation(entity, pSession->database());

        if (!pSession->isValid()) {
            emit dbError(pSession->firstError().text());
            emit dbErrorUpdate(pSession->firstError().text());
            return;
        }

        emit dataChanged();
    }

    QSharedPointer<T> loadById(long id) {
        QSharedPointer<T> entity;

        if (!checkPermission(PERM_READ)) {
            return entity;
        }

        entity = QSharedPointer<T>(new T);
        entity->setId(id);
        auto err = qx::dao::fetch_by_id_with_all_relation(entity);

        if (err.isValid()) {
            emit dbError(err.text());
            emit dbErrorRead(err.text());
        }

        return entity;
    }

    void load(QSharedPointer<T>& entity) {
        if (!checkPermission(PERM_READ)) {
            return;
        }

        auto err = qx::dao::fetch_by_id_with_all_relation(entity);

        if (err.isValid()) {
            emit dbError(err.text());
            emit dbErrorRead(err.text());
        }
    }

    QSharedPointer<T> reload(int id) {
        return loadById(id);
    }

    void erase(QSharedPointer<T> entity, qx::QxSession* pSession = nullptr) {
        if (!checkPermission(PERM_DELETE)) {
            return;
        }

        QScopedPointer<qx::QxSession> ptrSession;

        if (pSession == nullptr) {
            ptrSession.reset(new qx::QxSession());
            pSession = ptrSession.data();
        }

        *pSession += qx::dao::delete_by_id(entity);

        if (!pSession->isValid()) {
            qDebug() << pSession->firstError().text();
            emit dbError(pSession->firstError().text());
            emit dbErrorDelete(pSession->firstError().text());
        }
    }

    bool importData(IImporter *importer, IImportProgress *progress = nullptr) {
        int count = importer->recordCount();

        if (importer->isError()) {
            return false;
        }

        for (int i = 0; i < count - 1; i++) {
            QSharedPointer<QObject> qentity = importer->nextRecord();

            if (importer->isError() || qentity.isNull()) {
                return false;
            }

            QSharedPointer<T> entity = qentity.dynamicCast<T>();
            if (!entity.isNull()) {
                this->save(entity);
            }
            else
            {
                return false;
            }

            qApp->processEvents();

            if (progress != nullptr && progress->terminate())
            {
                return true;
            }

            if (progress != nullptr)
            {
                progress->updateProgress(i * 100 / count);
            }
        }

        return true;
    }

protected:
    bool checkPermission(const QString &permission) {
        if (!m_pluginId.isEmpty()) {
            PermissionEvaluator ev;
            if (!ev.hasPermission(m_pluginId, permission)) {
                emit permissionDenied(permission);
                return false;
            }
        }

        return true;
    }

    void addDateAndUser(QSharedPointer<T> entity, bool creating) {

        T *inner = entity.data();
        auto *obj = dynamic_cast<QObject*>(inner);

        if (obj == nullptr)
        {
            return;
        }

        if (creating)
        {
            if (!Context::instance().currentUser().isNull()) {
                obj->setProperty("createdBy", Context::instance().currentUser()->login());
            }

            obj->setProperty("created", QDateTime::currentDateTime());
        }
        else
        {
            obj->setProperty("updatedBy", Context::instance().currentUser()->login());
            obj->setProperty("updated", QDateTime::currentDateTime());
        }
    }

    virtual QString defaultSort() {
        return "";
    }
};

#endif // SERVICE_H