// 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;
    aclk_query_t tail;
    int block_push;
} aclk_query_queue = {
    .head = NULL,
    .tail = NULL,
    .block_push = 0
};

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

    ACLK_QUEUE_LOCK;
    if (aclk_query_queue.block_push) {
        ACLK_QUEUE_UNLOCK;
        if(!netdata_exit)
            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;
    }
    if (!aclk_query_queue.head) {
        aclk_query_queue.head = query;
        aclk_query_queue.tail = query;
        ACLK_QUEUE_UNLOCK;
        return 0;
    }
    // TODO deduplication
    aclk_query_queue.tail->next = query;
    aclk_query_queue.tail = query;
    ACLK_QUEUE_UNLOCK;
    return 0;

}

// Gets a pointer to the metric associated with a particular query type.
// NULL if the query type has no associated metric.
static inline volatile uint32_t *aclk_stats_qmetric_for_qtype(aclk_query_type_t qtype) {
    switch (qtype) {
        case HTTP_API_V2:
            return &aclk_metrics_per_sample.query_type_http;
        case ALARM_STATE_UPDATE:
            return &aclk_metrics_per_sample.query_type_alarm_upd;
        case METADATA_INFO:
            return &aclk_metrics_per_sample.query_type_metadata_info;
        case METADATA_ALARMS:
            return &aclk_metrics_per_sample.query_type_metadata_alarms;
        case CHART_NEW:
            return &aclk_metrics_per_sample.query_type_chart_new;
        case CHART_DEL:
            return &aclk_metrics_per_sample.query_type_chart_del;
        case REGISTER_NODE:
            return &aclk_metrics_per_sample.query_type_register_node;
        case NODE_STATE_UPDATE:
            return &aclk_metrics_per_sample.query_type_node_upd;
        default:
            return NULL;
    }
}

int aclk_queue_query(aclk_query_t query)
{
    int ret = _aclk_queue_query(query);
    if (!ret) {
        // local cache of query type before we wake up query thread, which may
        // free the query in a race.
        aclk_query_type_t qtype = query->type;
        QUERY_THREAD_WAKEUP;

        if (aclk_stats_enabled) {
            // get target query type metric before lock so we keep lock for
            // minimal time.
            volatile uint32_t *metric = aclk_stats_qmetric_for_qtype(qtype);

            ACLK_STATS_LOCK;
            aclk_metrics_per_sample.queries_queued++;
            if (metric)
                *metric += 1;
            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(!netdata_exit)
            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;
    }

    aclk_query_queue.head = ret->next;
    if (unlikely(!aclk_query_queue.head))
        aclk_query_queue.tail = aclk_query_queue.head;
    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;

    case CHART_NEW:
        freez(query->data.chart_add_del.chart_name);
        break;
    
    case ALARM_STATE_UPDATE:
        if (query->data.alarm_update)
            json_object_put(query->data.alarm_update);
        break;

    case NODE_STATE_UPDATE:
        freez((void*)query->data.node_update.claim_id);
        freez((void*)query->data.node_update.node_id);
        break;

    case REGISTER_NODE:
        freez((void*)query->data.node_creation.claim_id);
        freez((void*)query->data.node_creation.hostname);
        freez((void*)query->data.node_creation.machine_guid);
        break;

    case CHART_DIMS_UPDATE:
    case CHART_CONFIG_UPDATED:
    case CHART_RESET:
    case RETENTION_UPDATED:
    case UPDATE_NODE_INFO:
    case ALARM_LOG_HEALTH:
    case ALARM_PROVIDE_CFG:
    case ALARM_SNAPSHOT:
        freez(query->data.bin_payload.payload);
        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;
}
