// SPDX-License-Identifier: GPL-3.0-or-later

/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
*
* Copyright (C) 2013 - 2024, nymea GmbH
* Copyright (C) 2024 - 2025, chargebyte austria GmbH
*
* This file is part of nymea-plugins.
*
* nymea-plugins is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* nymea-plugins is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with nymea-plugins. If not, see <https://www.gnu.org/licenses/>.
*
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */

#ifndef SMTPCLIENT_H
#define SMTPCLIENT_H

#include <QQueue>
#include <QDebug>
#include <QObject>
#include <QTcpSocket>
#include <QSslSocket>
#include <QStringList>
#include <QLoggingCategory>

Q_DECLARE_LOGGING_CATEGORY(dcSmtpClient)

struct Message {
    QString subject;
    QString body;
    int id;
};

class SmtpClient : public QObject
{
    Q_OBJECT
public:

    enum AuthenticationMethod{
        AuthenticationMethodPlain,
        AuthenticationMethodLogin
    };
    Q_ENUM(AuthenticationMethod)

    enum State{
        StateIdle,
        StateInitialize,
        StateHandShake,
        StateAuthentification,
        StateStartTls,
        StateUser,
        StatePassword,
        StateTestLoginFinished,
        StateMail,
        StateRcpt,
        StateData,
        StateBody,
        StateQuit,
        StateClose
    };
    Q_ENUM(State)

    enum EncryptionType{
        EncryptionTypeNone,
        EncryptionTypeSSL,
        EncryptionTypeTLS
    };
    Q_ENUM(EncryptionType)

    explicit SmtpClient(QObject *parent = nullptr);

    void connectToHost();
    void testLogin();
    int sendMail(const QString &subject, const QString &body);

    void setHost(const QString &host);
    void setPort(const quint16 &port);
    void setEncryptionType(const EncryptionType &encryptionType);
    void setAuthenticationMethod(const AuthenticationMethod &authenticationMethod);
    void setUser(const QString &user);
    void setPassword(const QString &password);
    void setSender(const QString &sender);
    void setRecipients(const QStringList &recipients);

private:
    QSslSocket *m_socket = nullptr;
    State m_state = StateIdle;
    QString m_host = "127.0.0.1";
    quint16 m_port = 25;

    QString m_user;
    QString m_password;
    QString m_sender;
    AuthenticationMethod m_authenticationMethod;
    EncryptionType m_encryptionType;
    QStringList m_recipients;
    QQueue<QString> m_recipientsQueue;

    // Created for each message
    Message m_message;
    QString m_messageData;

    QQueue<Message> m_messageQueue;

    bool m_testLogin = false;

    QString createDateString();
    void setState(State state);

    void processServerResponse(int responseCode, const QString &response);

    void sendNextMail();
    void sendEmailInternally(const Message &message);

    void handleSmtpFailure();
    void handleUnexpectedSmtpCode(int responseCode, const QString &serverMessage);

signals:
    void sendMailFinished(bool success, int &id);
    void testLoginFinished(bool success);

private slots:

    void onSocketError(QAbstractSocket::SocketError error);
    void connected();
    void disconnected();
    void onEncrypted();
    void readData();
    void send(const QString &data);
};

#endif // SMTPCLIENT_H