#include "databaselms.h"

#include <QtSql>
#include <QSqlDatabase>
#include <QMessageBox>

DataBaseLMS::DataBaseLMS():
    db(nullptr)
{
    createConnection();
}

DataBaseLMS::~DataBaseLMS()
{
    deleteConnection();
}

bool DataBaseLMS::createConnection()
{
    db = new QSqlDatabase(QSqlDatabase::addDatabase(dbType));
    db->setDatabaseName(dbName);
    db->setUserName(dbUserName);
    db->setPassword(dbPassword);
    if(!db->open())
    {
        QMessageBox::critical(nullptr, dbName, "Connection error: " + db->lastError().text());
        return false;
    }
    else
    {
        QMessageBox::information(nullptr, dbName, "Connection is successful!");
        return true;
    }
}

void DataBaseLMS::deleteConnection()
{
    if(db != nullptr)
    {
        if(db->isOpen())
            db->close();
        delete  db;
    }
}

QList<Instructor> DataBaseLMS::selectAllInstructors()
{
    QList<Instructor> listInstructors;

    QString queryStr = QString("SELECT instructor_id, name, login, password, is_admin, archived, logged_in "
                                                 "FROM public.instructors "
                                                 "ORDER BY instructor_id ASC");

    QSqlQuery query(*db);
    if(!query.exec(queryStr))
    {
        messageWarningErrorQuery(queryStr);
    }
    else
    {
        while (query.next())
        {//Инструктор
            Instructor instructor;
            instructor.setID(query.value(0).toInt());
            instructor.setName(query.value(1).toString());
            instructor.setLogin(query.value(2).toString());
            instructor.setPassword(query.value(3).toString());
            instructor.setIsAdmin(query.value(4).toBool());
            instructor.setArchived(query.value(5).toBool());
            instructor.setLoggedIn(query.value(6).toBool());

            listInstructors.append(instructor);
        }
    }

    return listInstructors;
}

QList<Trainee> DataBaseLMS::selectAllTrainees()
{
    QList<Trainee> listTrainees;

    QString queryStr = QString("SELECT trainees.trainee_id, trainees.name, trainees.login, trainees.password, trainees.archived, trainees.logged_in, "
                                                 "groups.group_id, groups.name, "
                                                 "computers.computer_id, computers.name, computers.ip_address, "
                                                 "classrooms.classroom_id, classrooms.name "
                                                 "FROM public.trainees JOIN public.groups ON groups.group_id = trainees.group_trainee "
                                                 "LEFT OUTER JOIN public.computers ON computers.computer_id = trainees.computer_trainee "
                                                 "LEFT OUTER JOIN public.classrooms ON classrooms.classroom_id = computers.classroom_computer "
                                                 "ORDER BY groups.name, trainees.name ASC");

    QSqlQuery query(*db);
    if(!query.exec(queryStr))
    {
        messageWarningErrorQuery(queryStr);
    }
    else
    {
        while (query.next())
        {//Обучаемый
            Trainee trainee;

            trainee.setID(query.value(0).toInt());
            trainee.setName(query.value(1).toString());
            trainee.setLogin(query.value(2).toString());
            trainee.setPassword(query.value(3).toString());
            trainee.setArchived(query.value(4).toBool());                      
            trainee.setLoggedIn(query.value(5).toBool());

            Group group = Group(query.value(6).toInt(), query.value(7).toString());
            trainee.setGroup(group);

            Classroom classroom = Classroom(query.value(11).toInt(), query.value(12).toString());
            Computer computer = Computer(query.value(8).toInt(), query.value(9).toString(), query.value(10).toString(), classroom);
            trainee.setComputer(computer);

            trainee.setTasks(selectTasksOfTrainee(trainee.getID()));

            listTrainees.append(trainee);
        }
    }

    return listTrainees;
}

QList<Group> DataBaseLMS::selectAllGroups()
{
    QList<Group> listGroups;

    QString queryStr = QString("SELECT group_id, name "
                                                 "FROM public.groups "
                                                 "ORDER BY group_id ASC");

    QSqlQuery query(*db);
    if(!query.exec(queryStr))
    {
        messageWarningErrorQuery(queryStr);
    }
    else
    {
        while (query.next())
        {//Группа
            Group group;
            group.setID(query.value(0).toInt());
            group.setName(query.value(1).toString());

            listGroups.append(group);
        }
    }

    return listGroups;
}

int DataBaseLMS::insertInstructor(Instructor instructor)
{
    QString queryStr = QString("INSERT INTO public.instructors (name, login, password, is_admin, archived, logged_in) "
                                                 "VALUES ('%1', '%2', '%3', %4, %5, %6) RETURNING instructor_id").arg(
                                                        instructor.getName(),
                                                        instructor.getLogin(),
                                                        instructor.getPassword(),
                                                        instructor.getIsAdmin() ? "true" : "false",
                                                        instructor.getArchived() ? "true" : "false",
                                                        instructor.getLoggedIn() ? "true" : "false");

    return queryExec(queryStr);
}

int DataBaseLMS::deleteInstructor(int instructor_id)
{
    QString queryStr = QString("DELETE FROM public.instructors WHERE instructor_id = %1 RETURNING instructors.instructor_id").arg(QString::number(instructor_id));

    return queryExec(queryStr);
}

int DataBaseLMS::updateInstructor(Instructor instructor)
{
    QString queryStr = QString("UPDATE public.instructors "
                                                 "SET name = '%1', login = '%2', password = '%3', is_admin = %4, archived = %5, logged_in = %6 "
                                                 "WHERE instructor_id = %7 RETURNING instructors.instructor_id").arg(
                                                        instructor.getName(),
                                                        instructor.getLogin(),
                                                        instructor.getPassword(),
                                                        instructor.getIsAdmin() ? "true" : "false",
                                                        instructor.getArchived() ? "true" : "false",
                                                        instructor.getLoggedIn() ? "true" : "false",
                                                        QString::number(instructor.getID()) );

    return queryExec(queryStr);
}

int DataBaseLMS::insertGroup(Group group)
{
    QString queryStr = QString("INSERT INTO public.groups (name) "
                                                 "VALUES ('%1') RETURNING groups.group_id").arg(
                                                        group.getName());

    return queryExec(queryStr);
}

int DataBaseLMS::deleteGroup(int group_id)
{
    QString queryStr = QString("DELETE FROM public.groups WHERE group_id = %1 RETURNING groups.group_id").arg(QString::number(group_id));

    return queryExec(queryStr);
}

int DataBaseLMS::updateGroup(Group group)
{
    QString queryStr = QString("UPDATE public.groups SET name = '%1' WHERE group_id = %2 RETURNING groups.group_id").arg(
                                                        group.getName(),
                                                        QString::number(group.getID()) );

    return queryExec(queryStr);
}

int DataBaseLMS::insertTrainee(Trainee trainee)
{
    QString queryStr = QString("INSERT INTO public.trainees (name, login, password, archived, logged_in, group_trainee) "
                                                 "VALUES ('%1', '%2', '%3', %4, %5, %6) RETURNING trainees.trainee_id").arg(
                                                        trainee.getName(),
                                                        trainee.getLogin(),
                                                        trainee.getPassword(),
                                                        trainee.getArchived() ? "true" : "false",
                                                        trainee.getLoggedIn() ? "true" : "false",
                                                        QString::number(trainee.getGroup().getID()));

    return queryExec(queryStr);
}

int DataBaseLMS::deleteTrainee(int trainee_id)
{
    QString queryStr = QString("DELETE FROM public.trainees WHERE trainee_id = %1 RETURNING trainees.trainee_id").arg(QString::number(trainee_id));

    return queryExec(queryStr);
}

int DataBaseLMS::updateTrainee(Trainee trainee)
{
    QString computer_id = (trainee.getComputer().getID() == 0 ? QStringLiteral("null") : QString::number(trainee.getComputer().getID()));

    QString queryStr = QString("UPDATE public.trainees "
                                                 "SET name = '%1', login = '%2', password = '%3', archived = %4, logged_in = %5, "
                                                 "group_trainee = %6, "
                                                 "computer_trainee = %7 "
                                                 "WHERE trainee_id = %8 RETURNING trainees.trainee_id").arg(
                                                        trainee.getName(),
                                                        trainee.getLogin(),
                                                        trainee.getPassword(),
                                                        trainee.getArchived() ? "true" : "false",
                                                        trainee.getLoggedIn() ? "true" : "false",
                                                        QString::number(trainee.getGroup().getID()),
                                                        computer_id,
                                                        QString::number(trainee.getID()) );

    return queryExec(queryStr);
}

QList<Task> DataBaseLMS::selectTasksOfTrainee(int trainee_id)
{
    QList<Task> tasks;

    QString queryStr = QString("SELECT tasks.task_id, tasks.name "
                                "FROM public.trainees "
                                "JOIN public.trainees_tasks ON trainees_tasks.trainee_id = trainees.trainee_id "
                                "JOIN public.tasks ON tasks.task_id = trainees_tasks.task_id "
                                "WHERE trainees.trainee_id = %1 "
                                "ORDER BY tasks.name ASC").arg(
                                                    trainee_id);

    QSqlQuery query(*db);
    if(!query.exec(queryStr))
    {
        messageWarningErrorQuery(queryStr);
    }
    else
    {
        while (query.next())
        {//Задача
            Task task;
            task.setID(query.value(0).toInt());
            task.setName(query.value(1).toString());
            tasks.append(task);
        }
    }

    return tasks;
}

int DataBaseLMS::queryExec(QString queryStr)
{
    QSqlQuery query(*db);
    if(!query.exec(queryStr))
    {
        messageWarningErrorQuery(queryStr);
        return 0;
    }
    else
    {
        if(query.next())
            return query.value(0).toInt();
        else
            return 0;
    }
}

void DataBaseLMS::messageWarningErrorQuery(QString queryStr)
{
    QMessageBox::warning(nullptr, dbName, "Error query: " + queryStr + "\n" + db->lastError().text());
}