/* ------------------------------------------------------------------
 * Copyright (C) 2017 AVT GmbH - Fabien Vercasson
 * Copyright (C) 2019 Matthias P. Braendli
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
 * express or implied.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 * -------------------------------------------------------------------
 */

#include "OrderedQueue.h"
#include <cstring>
#include <cstdio>
#include <stdint.h>

#define DEBUG(fmt, A...)   fprintf(stderr, "OrderedQueue: " fmt, ##A)
//#define DEBUG(x...)
#define ERROR(fmt, A...)   fprintf(stderr, "OrderedQueue: ERROR " fmt, ##A)

OrderedQueue::OrderedQueue(int countModulo, size_t capacity) :
    _countModulo(countModulo),
    _capacity(capacity)
{
}

void OrderedQueue::push(int32_t count, const uint8_t* buf, size_t size)
{
//    DEBUG("OrderedQueue::push count=%d\n", count);
    count = (count+_countModulo) % _countModulo;

    // First frame makes the count initialisation.
    if (_lastCount == -1) {
        _lastCount = (count+_countModulo-1) % _countModulo;
    }

    if (_stock.size() < _capacity) {
        if (_stock.find(count) == _stock.end()) {
            // count already exists, duplicated frame
            // Replace the old one by the new one.
            // the old one could a an old frame from the previous count loop
            _duplicated++;
            DEBUG("Duplicated count=%d\n", count);
        }

        OrderedQueueData oqd(size);
        copy(buf, buf + size, oqd.begin());
        _stock[count] = move(oqd);
    }
    else {
        _overruns++;
        if (_overruns < 100) {
            DEBUG("Overruns (size=%zu) count=%d not inserted\n", _stock.size(), count);
        }
        else if (_overruns == 100) {
            DEBUG("stop displaying Overruns\n");
        }
    }
}

bool OrderedQueue::availableData() const
{
    // TODO Wait for filling gaps
    return _stock.size() > 0;
}

size_t OrderedQueue::pop(std::vector<uint8_t>& buf, int32_t *retCount)
{
    size_t nbBytes = 0;
    uint32_t gap = 0;

    if (_stock.size() > 0) {
        int32_t nextCount = (_lastCount+1) % _countModulo;
        bool found = false;
        while (not found) {
            try {
                auto& oqd = _stock.at(nextCount);
                buf = move(oqd);
                _stock.erase(nextCount);
                _lastCount = nextCount;
                if (retCount) *retCount = _lastCount;
                found = true;
            }
            catch (const std::out_of_range&)
            {
                if (_stock.size() < _capacity) {
                    found = true;
                }
                else {
                    // Search for the new reference count, starting from the current one
                    // This could be optimised, but the modulo makes things
                    // not easy.
                    gap++;
                    nextCount = (nextCount+1) % _countModulo;
                }
            }
        }
    }

    if (gap > 0) {
        DEBUG("Count jump of %d\n", gap);
    }
//    if (nbBytes > 0 && retCount) DEBUG("OrderedQueue::pop count=%d\n", *retCount);
    return nbBytes;
}