#ifndef AUTHMETHODS_H
#define AUTHMETHODS_H

#include <qhttpserverrequest.h>
#include <qhttpserverresponse.h>
#include <qcryptographichash.h>
#include <qjsondocument.h>
#include <QJsonObject>
#include <qsqldatabase.h>
#include <qsqlerror.h>
#include <qsqlquery.h>
#include <QUuid>
#include <QDateTime>
#include <QDebug>

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

QString generateToken() {
    return QUuid::createUuid().toString(QUuid::WithoutBraces);
}

QHttpServerResponse login(const QJsonObject &json) {
    QString username = json["username"].toString();
    QString password = json["password"].toString();

    QSqlDatabase db = QSqlDatabase::database();

    QSqlQuery query(db);

    query.prepare(QString("SELECT id, password FROM public.users WHERE username = '%1'").arg(username));

    if (!query.exec() || !query.next()) {
        QHttpServerResponse response("Invalid username or password", QHttpServerResponse::StatusCode::Unauthorized);
        response.setHeader("Access-Control-Allow-Origin", "*");
        response.setHeader("Access-Control-Allow-Methods", "GET, POST, OPTIONS, DELETE");
        response.setHeader("Access-Control-Allow-Headers", "Content-Type, Authorization");
        return response;
    }

    QString hashedPassword = query.value("password").toString();

    if (hashedPassword != hashPassword(password)) {
        QHttpServerResponse response("Invalid username or password", QHttpServerResponse::StatusCode::Unauthorized);
        response.setHeader("Access-Control-Allow-Origin", "*");
        response.setHeader("Access-Control-Allow-Methods", "GET, POST, OPTIONS, DELETE");
        response.setHeader("Access-Control-Allow-Headers", "Content-Type, Authorization");
        return response;
    }

    QString token = generateToken();
    int userId = query.value("id").toInt();
    QDateTime expiryDate = QDateTime::currentDateTimeUtc().addSecs(24 * 3600);

    query.prepare("INSERT INTO public.tokens (user_id, token, expiry_date) VALUES (:user_id, :token, :expiry_date)");
    query.bindValue(":user_id", userId);
    query.bindValue(":token", token);
    query.bindValue(":expiry_date", expiryDate);

    if (!query.exec()) {
        qDebug() << "Error inserting token";
        QHttpServerResponse response("Token generation failed", QHttpServerResponse::StatusCode::InternalServerError);
        response.setHeader("Access-Control-Allow-Origin", "*");
        response.setHeader("Access-Control-Allow-Methods", "GET, POST, OPTIONS, DELETE");
        response.setHeader("Access-Control-Allow-Headers", "Content-Type, Authorization");
        return response;
    }

    QJsonObject jsonResponse;
    jsonResponse["token"] = token;
    QByteArray responseBody = QJsonDocument(jsonResponse).toJson();

    QHttpServerResponse response(responseBody, QHttpServerResponse::StatusCode::Ok);
    response.setHeader("Access-Control-Allow-Origin", "*");
    response.setHeader("Access-Control-Allow-Methods", "GET, POST, OPTIONS, DELETE");
    response.setHeader("Access-Control-Allow-Headers", "Content-Type, Authorization");

    return response;
}

QHttpServerResponse loginUser(const QHttpServerRequest &request) {
    auto body = request.body();
    QJsonDocument jsonRequest = QJsonDocument::fromJson(body);
    qDebug() << jsonRequest;

    if (!jsonRequest.isObject()) {
        QHttpServerResponse response("Invalid Request!", QHttpServerResponse::StatusCode::BadRequest);
        response.setHeader("Access-Control-Allow-Origin", "*");
        response.setHeader("Access-Control-Allow-Methods", "GET, POST, OPTIONS, DELETE");
        response.setHeader("Access-Control-Allow-Headers", "Content-Type, Authorization");
        return response;
    }

    return login(jsonRequest.object());
}


QHttpServerResponse checkAuth(const QString &token) {
    QSqlDatabase db = QSqlDatabase::database();
    QSqlQuery query(db);

    query.prepare(QString("SELECT user_id, expiry_date FROM tokens WHERE token = :token"));
    query.bindValue(":token", token);

    if (!query.exec() || !query.next()) {
        QHttpServerResponse response("Invalid token", QHttpServerResponse::StatusCode::Unauthorized);

        response.setHeader("Access-Control-Allow-Origin", "*");
        response.setHeader("Access-Control-Allow-Methods", "GET, POST, OPTIONS");
        response.setHeader("Access-Control-Allow-Headers", "Content-Type, Authorization");
        return response;
    }

    QDateTime expiryDate = query.value("expiry_date").toDateTime();
    if (QDateTime::currentDateTimeUtc() > expiryDate) {
        QHttpServerResponse response("Token expired", QHttpServerResponse::StatusCode::Unauthorized);

        response.setHeader("Access-Control-Allow-Origin", "*");
        response.setHeader("Access-Control-Allow-Methods", "GET, POST, OPTIONS");
        response.setHeader("Access-Control-Allow-Headers", "Content-Type, Authorization");
        return response;
    }

    QJsonObject jsonResponse;
    jsonResponse["status"] = "Authenticated";
    QHttpServerResponse response(QJsonDocument(jsonResponse).toJson(), QHttpServerResponse::StatusCode::Ok);

    response.setHeader("Access-Control-Allow-Origin", "*");
    response.setHeader("Access-Control-Allow-Methods", "GET, POST, OPTIONS");
    response.setHeader("Access-Control-Allow-Headers", "Content-Type, Authorization");

    return response;
}

QHttpServerResponse authUser(const QHttpServerRequest &request) {
    QList<QPair<QByteArray, QByteArray>> headers = request.headers();
    QString token;

    for (const auto &header : headers) {
        if (header.first.toLower() == "authorization") {
            QString authHeader = QString::fromUtf8(header.second);
            if (authHeader.startsWith("Bearer ")) {
                token = authHeader.mid(7);
            }
            break;
        }
    }

    if (token.isEmpty()) {
        QHttpServerResponse response("No token provided", QHttpServerResponse::StatusCode::Unauthorized);
        response.setHeader("Access-Control-Allow-Origin", "*");
        response.setHeader("Access-Control-Allow-Methods", "GET, POST, OPTIONS");
        response.setHeader("Access-Control-Allow-Headers", "Content-Type, Authorization");
        return response;
    }

    return checkAuth(token);
}

#endif // AUTHMETHODS_H