#include "database.h"
#include <QSqlQuery>
#include <QSqlError>
#include <QSqlRecord>
#include <QFile>
#include <QTextStream>
#include <QDir>

Database& Database::instance() {
    static Database instance;
    return instance;
}

bool Database::initialize() {
    m_db = QSqlDatabase::addDatabase("QSQLITE", "StationDB");
    QString dbPath = QDir::currentPath() + "/station.db";
    m_db.setDatabaseName(dbPath);
    
    if (!m_db.open()) {
        qDebug() << QDir::currentPath() + "/station.db";
        qDebug() << "Database open error:" << m_db.lastError().text();
        return false;
    }
    
    QSqlQuery query(m_db);
    
    query.exec("CREATE TABLE IF NOT EXISTS users ("
               "id INTEGER PRIMARY KEY AUTOINCREMENT, "
               "username TEXT UNIQUE NOT NULL, "
               "password TEXT NOT NULL, "
               "role TEXT NOT NULL)");
    
    query.exec("CREATE TABLE IF NOT EXISTS routes ("
               "id INTEGER PRIMARY KEY AUTOINCREMENT, "
               "route_name TEXT NOT NULL, "
               "departure_time TEXT NOT NULL, "
               "price REAL NOT NULL, "
               "total_seats INTEGER NOT NULL, "
               "available_seats INTEGER NOT NULL)");
    
    query.exec("CREATE TABLE IF NOT EXISTS tickets ("
               "id INTEGER PRIMARY KEY AUTOINCREMENT, "
               "route_id INTEGER NOT NULL, "
               "passenger_name TEXT NOT NULL, "
               "document_number TEXT NOT NULL, "
               "seat_count INTEGER NOT NULL, "
               "total_price REAL NOT NULL, "
               "seller_id INTEGER NOT NULL, "
               "sale_date TEXT NOT NULL, "
               "FOREIGN KEY (route_id) REFERENCES routes(id), "
               "FOREIGN KEY (seller_id) REFERENCES users(id))");
    
    query.exec("SELECT COUNT(*) FROM users WHERE role = 'admin'");
    if (query.next() && query.value(0).toInt() == 0) {
        addUser("admin", "admin123", "admin");
    }
    
    return true;
}

QString Database::hashPassword(const QString& password) {
    QByteArray hash = QCryptographicHash::hash(
        password.toUtf8(), QCryptographicHash::Sha256);
    return hash.toHex();
}

bool Database::authenticate(const QString& username, const QString& password) {
    QSqlQuery query(m_db);
    query.prepare("SELECT password FROM users WHERE username = ?");
    query.addBindValue(username);
    
    if (query.exec() && query.next()) {
        return query.value(0).toString() == hashPassword(password);
    }
    return false;
}

User Database::getUser(const QString& username) {
    User user;
    QSqlQuery query(m_db);
    query.prepare("SELECT id, username, password, role FROM users WHERE username = ?");
    query.addBindValue(username);
    
    if (query.exec() && query.next()) {
        user.id = query.value(0).toInt();
        user.username = query.value(1).toString();
        user.password = query.value(2).toString();
        user.role = query.value(3).toString();
    }
    return user;
}

QVector<User> Database::getAllUsers() {
    QVector<User> users;
    QSqlQuery query("SELECT id, username, password, role FROM users", m_db);
    
    while (query.next()) {
        User user;
        user.id = query.value(0).toInt();
        user.username = query.value(1).toString();
        user.password = query.value(2).toString();
        user.role = query.value(3).toString();
        users.append(user);
    }
    return users;
}

bool Database::addUser(const QString& username, const QString& password, const QString& role) {
    QSqlQuery query(m_db);
    query.prepare("INSERT INTO users (username, password, role) VALUES (?, ?, ?)");
    query.addBindValue(username);
    query.addBindValue(hashPassword(password));
    query.addBindValue(role);
    return query.exec();
}

bool Database::deleteUser(int id) {
    QSqlQuery query(m_db);
    query.prepare("DELETE FROM users WHERE id = ? AND role != 'admin'");
    query.addBindValue(id);
    return query.exec();
}

QVector<Route> Database::getAllRoutes() {
    QVector<Route> routes;
    QSqlQuery query("SELECT id, route_name, departure_time, price, total_seats, available_seats FROM routes", m_db);
    
    while (query.next()) {
        Route route;
        route.id = query.value(0).toInt();
        route.routeName = query.value(1).toString();
        route.departureTime = query.value(2).toString();
        route.price = query.value(3).toDouble();
        route.totalSeats = query.value(4).toInt();
        route.availableSeats = query.value(5).toInt();
        routes.append(route);
    }
    return routes;
}

Route Database::getRoute(int id) {
    Route route;
    QSqlQuery query(m_db);
    query.prepare("SELECT id, route_name, departure_time, price, total_seats, available_seats FROM routes WHERE id = ?");
    query.addBindValue(id);
    
    if (query.exec() && query.next()) {
        route.id = query.value(0).toInt();
        route.routeName = query.value(1).toString();
        route.departureTime = query.value(2).toString();
        route.price = query.value(3).toDouble();
        route.totalSeats = query.value(4).toInt();
        route.availableSeats = query.value(5).toInt();
    }
    return route;
}

bool Database::addRoute(const QString& routeName, const QString& departureTime,
                        double price, int totalSeats) {
    QSqlQuery query(m_db);
    query.prepare("INSERT INTO routes (route_name, departure_time, price, total_seats, available_seats) "
                  "VALUES (?, ?, ?, ?, ?)");
    query.addBindValue(routeName);
    query.addBindValue(departureTime);
    query.addBindValue(price);
    query.addBindValue(totalSeats);
    query.addBindValue(totalSeats);
    return query.exec();
}

bool Database::updateRoute(const Route& route) {
    QSqlQuery query(m_db);
    query.prepare("UPDATE routes SET route_name = ?, departure_time = ?, price = ?, "
                  "total_seats = ?, available_seats = ? WHERE id = ?");
    query.addBindValue(route.routeName);
    query.addBindValue(route.departureTime);
    query.addBindValue(route.price);
    query.addBindValue(route.totalSeats);
    query.addBindValue(route.availableSeats);
    query.addBindValue(route.id);
    return query.exec();
}

bool Database::deleteRoute(int id) {
    QSqlQuery query(m_db);
    query.prepare("DELETE FROM routes WHERE id = ?");
    query.addBindValue(id);
    return query.exec();
}

bool Database::updateAvailableSeats(int routeId, int change) {
    QSqlQuery query(m_db);
    query.prepare("UPDATE routes SET available_seats = available_seats + ? WHERE id = ?");
    query.addBindValue(change);
    query.addBindValue(routeId);
    return query.exec();
}

QVector<Ticket> Database::getTicketsByRoute(int routeId) {
    QVector<Ticket> tickets;
    QSqlQuery query(m_db);
    query.prepare("SELECT t.id, t.route_id, r.route_name, t.passenger_name, "
                  "t.document_number, t.seat_count, t.total_price, t.seller_id, "
                  "u.username, t.sale_date "
                  "FROM tickets t "
                  "JOIN routes r ON t.route_id = r.id "
                  "JOIN users u ON t.seller_id = u.id "
                  "WHERE t.route_id = :route_id");
    query.bindValue(":route_id", routeId);

    query.exec();
    
    while (query.next()) {
        Ticket ticket;
        ticket.id = query.value(0).toInt();
        ticket.routeId = query.value(1).toInt();
        ticket.routeName = query.value(2).toString();
        ticket.passengerName = query.value(3).toString();
        ticket.documentNumber = query.value(4).toString();
        ticket.seatCount = query.value(5).toInt();
        ticket.totalPrice = query.value(6).toDouble();
        ticket.sellerId = query.value(7).toInt();
        ticket.sellerName = query.value(8).toString();
        ticket.saleDate = query.value(9).toString();
        tickets.append(ticket);
    }
    return tickets;
}

QVector<Ticket> Database::getAllTickets() {
    QVector<Ticket> tickets;
    QSqlQuery query("SELECT t.id, t.route_id, r.route_name, t.passenger_name, "
                    "t.document_number, t.seat_count, t.total_price, t.seller_id, "
                    "u.username, t.sale_date "
                    "FROM tickets t "
                    "JOIN routes r ON t.route_id = r.id "
                    "JOIN users u ON t.seller_id = u.id "
                    "ORDER BY t.sale_date DESC",m_db);

    query.exec();
    
    while (query.next()) {
        Ticket ticket;
        ticket.id = query.value(0).toInt();
        ticket.routeId = query.value(1).toInt();
        ticket.routeName = query.value(2).toString();
        ticket.passengerName = query.value(3).toString();
        ticket.documentNumber = query.value(4).toString();
        ticket.seatCount = query.value(5).toInt();
        ticket.totalPrice = query.value(6).toDouble();
        ticket.sellerId = query.value(7).toInt();
        ticket.sellerName = query.value(8).toString();
        ticket.saleDate = query.value(9).toString();
        tickets.append(ticket);
    }
    return tickets;
}

bool Database::addTicket(int routeId, const QString& passengerName,
                        const QString& documentNumber, int seatCount, int sellerId) {
    Route route = getRoute(routeId);
    double totalPrice = route.price * seatCount;

    QSqlQuery query(m_db);
    query.prepare("INSERT INTO tickets (route_id, passenger_name, document_number, "
                  "seat_count, total_price, seller_id, sale_date) VALUES (?, ?, ?, ?, ?, ?, ?)");
    query.addBindValue(routeId);
    query.addBindValue(passengerName);
    query.addBindValue(documentNumber);
    query.addBindValue(seatCount);
    query.addBindValue(totalPrice);
    query.addBindValue(sellerId);
    query.addBindValue(QDateTime::currentDateTime().toString("yyyy-MM-dd HH:mm:ss"));
    
    if (query.exec()) {
        return updateAvailableSeats(routeId, -seatCount);
    }
    return false;
}

bool Database::deleteTicket(int id) {
    QSqlQuery query(m_db);
    query.prepare("SELECT route_id, seat_count FROM tickets WHERE id = ?");
    query.addBindValue(id);
    
    if (query.exec() && query.next()) {
        int routeId = query.value(0).toInt();
        int seatCount = query.value(1).toInt();
        
        query.prepare("DELETE FROM tickets WHERE id = ?");
        query.addBindValue(id);
        
        if (query.exec()) {
            return updateAvailableSeats(routeId, seatCount);
        }
    }
    return false;
}

int Database::getLastTicketId() {
    QSqlQuery query("SELECT last_insert_rowid()", m_db);
    if (query.next()) {
        return query.value(0).toInt();
    }
    return -1;
}