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

#include "aclk_query_queue.h"
#include "aclk_query.h"
#include "aclk_stats.h"

static netdata_mutex_t aclk_query_queue_mutex = NETDATA_MUTEX_INITIALIZER;
#define ACLK_QUEUE_LOCK netdata_mutex_lock(&aclk_query_queue_mutex)
#define ACLK_QUEUE_UNLOCK netdata_mutex_unlock(&aclk_query_queue_mutex)

static struct aclk_query_queue {
    aclk_query_t head;
    int block_push;
} aclk_query_queue = {
    .head = NULL,
    .block_push = 0
};

static inline int _aclk_queue_query(aclk_query_t query)
{
    now_monotonic_high_precision_timeval(&query->created_tv);
    query->created = now_realtime_usec();

    ACLK_QUEUE_LOCK;
    if (aclk_query_queue.block_push) {
        ACLK_QUEUE_UNLOCK;
        if(service_running(SERVICE_ACLK | ABILITY_DATA_QUERIES))
            netdata_log_error("Query Queue is blocked from accepting new requests. This is normally the case when ACLK prepares to shutdown.");
        aclk_query_free(query);
        return 1;
    }
    DOUBLE_LINKED_LIST_APPEND_ITEM_UNSAFE(aclk_query_queue.head, query, prev, next);
    ACLK_QUEUE_UNLOCK;
    return 0;

}

int aclk_queue_query(aclk_query_t query)
{
    int ret = _aclk_queue_query(query);
    if (!ret) {
        QUERY_THREAD_WAKEUP;
        if (aclk_stats_enabled) {
            ACLK_STATS_LOCK;
            aclk_metrics_per_sample.queries_queued++;
            ACLK_STATS_UNLOCK;
        }
    }
    return ret;
}

aclk_query_t aclk_queue_pop(void)
{
    aclk_query_t ret;

    ACLK_QUEUE_LOCK;
    if (aclk_query_queue.block_push) {
        ACLK_QUEUE_UNLOCK;
        if(service_running(SERVICE_ACLK | ABILITY_DATA_QUERIES))
            netdata_log_error("POP Query Queue is blocked from accepting new requests. This is normally the case when ACLK prepares to shutdown.");
        return NULL;
    }

    ret = aclk_query_queue.head;
    if (!ret) {
        ACLK_QUEUE_UNLOCK;
        return ret;
    }

    DOUBLE_LINKED_LIST_REMOVE_ITEM_UNSAFE(aclk_query_queue.head, ret, prev, next);
    ACLK_QUEUE_UNLOCK;

    ret->next = NULL;
    return ret;
}

void aclk_queue_flush(void)
{
    aclk_query_t query = aclk_queue_pop();
    while (query) {
        aclk_query_free(query);
        query = aclk_queue_pop();
    }
}

aclk_query_t aclk_query_new(aclk_query_type_t type)
{
    aclk_query_t query = callocz(1, sizeof(struct aclk_query));
    query->type = type;
    return query;
}

void aclk_query_free(aclk_query_t query)
{
    switch (query->type) {
    case HTTP_API_V2:
        freez(query->data.http_api_v2.payload);
        if (query->data.http_api_v2.query != query->dedup_id)
            freez(query->data.http_api_v2.query);
        break;

    default:
        break;
    }

    freez(query->dedup_id);
    freez(query->callback_topic);
    freez(query->msg_id);
    freez(query);
}

void aclk_queue_lock(void)
{
    ACLK_QUEUE_LOCK;
    aclk_query_queue.block_push = 1;
    ACLK_QUEUE_UNLOCK;
}

void aclk_queue_unlock(void)
{
    ACLK_QUEUE_LOCK;
    aclk_query_queue.block_push = 0;
    ACLK_QUEUE_UNLOCK;
}
