/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4; fill-column: 100 -*- */
/*
 * This file is part of the LibreOffice project.
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 */

#include "MessageQueue.hpp"

#include <algorithm>

MessageQueue::~MessageQueue()
{
    clear();
}

void MessageQueue::put(const Payload& value)
{
    std::unique_lock<std::mutex> lock(_mutex);
    put_impl(value);
    lock.unlock();
    _cv.notify_one();
}

MessageQueue::Payload MessageQueue::get()
{
    std::unique_lock<std::mutex> lock(_mutex);
    _cv.wait(lock, [this] { return wait_impl(); });
    return get_impl();
}

void MessageQueue::clear()
{
    std::unique_lock<std::mutex> lock(_mutex);
    clear_impl();
}

void MessageQueue::remove_if(std::function<bool(const Payload&)> pred)
{
    std::unique_lock<std::mutex> lock(_mutex);
    std::remove_if(_queue.begin(), _queue.end(), pred);
}

void MessageQueue::put_impl(const Payload& value)
{
    _queue.push_back(value);
}

bool MessageQueue::wait_impl() const
{
    return _queue.size() > 0;
}

MessageQueue::Payload MessageQueue::get_impl()
{
    auto result = _queue.front();
    _queue.pop_front();
    return result;
}

void MessageQueue::clear_impl()
{
    _queue.clear();
}

void BasicTileQueue::put_impl(const Payload& value)
{
    const auto msg = std::string(&value[0], value.size());
    if (msg == "canceltiles")
    {
        // remove all the existing tiles from the queue
        _queue.erase(std::remove_if(_queue.begin(), _queue.end(),
                    [](const Payload& v)
                    {
                        // must not remove the tiles with 'id=', they are special, used
                        // eg. for previews etc.
                        const auto tmp = std::string(&v[0], v.size());
                        return (tmp.compare(0, 5, "tile ") == 0) && (tmp.find("id=") == std::string::npos);
                    }
                    ),
                _queue.end());

        // put the "canceltiles" in front of other messages
        _queue.push_front(value);
    }
    else
    {
        MessageQueue::put_impl(value);
    }
}

void TileQueue::put_impl(const Payload& value)
{
    const auto msg = std::string(&value[0], value.size());
    if (msg.compare(0, 5, "tile ") == 0)
    {
        // TODO: implement a real re-ordering here, so that the tiles closest to
        // the cursor are returned first.
        // * we will want to put just a general "tile" message to the queue
        // * add a std::set that handles the tiles
        // * change the get_impl() to decide which tile is the correct one to
        //   be returned
        // * we will also need to be informed about the position of the cursor
        //   so that get_impl() returns optimal results
        //
        // For now: just don't put duplicates into the queue
        for (auto it = _queue.cbegin(); it != _queue.cend(); ++it)
        {
            if (value == *it)
            {
                return;
            }
        }
    }

    BasicTileQueue::put_impl(value);
}

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