// Copyright (c) 2022 Proton AG
//
// This file is part of Proton Mail Bridge.
//
// Proton Mail Bridge 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.
//
// Proton Mail Bridge 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 Proton Mail Bridge. If not, see <https://www.gnu.org/licenses/>.


#include "Pch.h"
#include "Overseer.h"
#include "Exception.h"


//****************************************************************************************************************************************************
/// \param[in] worker The worker.
/// \param[in] parent The parent object of the worker.
//****************************************************************************************************************************************************
Overseer::Overseer(Worker *worker, QObject *parent)
    : QObject(parent)
    , thread_(new QThread(parent))
    , worker_(worker)
{
    if (!worker_)
        throw Exception("Overseer cannot accept a nil worker.");
}


//****************************************************************************************************************************************************
//
//****************************************************************************************************************************************************
Overseer::~Overseer()
{
    this->release();
}


//****************************************************************************************************************************************************
/// \param[in] autorelease Should the overseer automatically release the worker and thread when done.
//****************************************************************************************************************************************************
void Overseer::startWorker(bool autorelease) const
{
    if (!worker_)
        throw Exception("Cannot start overseer with null worker.");
    if (!thread_)
        throw Exception("Cannot start overseer with null thread.");

    worker_->moveToThread(thread_);
    connect(thread_, &QThread::started, worker_, &Worker::run);
    connect(worker_, &Worker::finished, [&]() {thread_->quit(); }); // for unkwown reason, connect to the QThread::quit slot does not work...
    connect(worker_, &Worker::error, [&]() { thread_->quit(); });

    if (autorelease)
    {
        connect(worker_, &Worker::error, this, &Overseer::release);
        connect(worker_, &Worker::finished, this, &Overseer::release);
    }

    thread_->start();
}


//****************************************************************************************************************************************************
//
//****************************************************************************************************************************************************
void Overseer::release()
{
    if (worker_)
    {
        worker_->deleteLater();
        worker_ = nullptr;
    }

    if (thread_)
    {
        if (!thread_->isFinished())
        {
            thread_->quit();
            thread_->wait();
        }
        thread_->deleteLater();
        thread_ = nullptr;
    }
}


//****************************************************************************************************************************************************
/// \return true iff the worker is finished.
//****************************************************************************************************************************************************
bool Overseer::isFinished() const
{
    if ((!worker_) || (!worker_->thread()))
        return true;

    return worker_->thread()->isFinished();
}


//****************************************************************************************************************************************************
/// \return The worker.
//****************************************************************************************************************************************************
Worker *Overseer::worker() const
{
    return worker_;
}