/* See the DRL-LICENSE file for this file's software license. */

#include <arpa/inet.h>
#include <assert.h>
#include <inttypes.h>
#include <netinet/in.h>
#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/time.h>
#include <sys/types.h>
#include <time.h>

#include "common_accounting.h"
#include "simple.h"
#include "logging.h"

simple_flow_table simple_table_create(common_accounting_t *common) {
    simple_flow_table table = malloc(sizeof(struct sim_flow_table));

    if (table == NULL) {
        return NULL;
    }

    memset(table, 0, sizeof(struct sim_flow_table));
    table->common = common;
    table->hash_function = NULL;

    gettimeofday(&table->common->last_update, NULL);

    return table;
}

void simple_table_destroy(simple_flow_table table) {
    free(table);
}

int simple_table_sample(simple_flow_table table, const key_flow *key) {
    /* Update aggregate. */
    table->common->bytes_since += key->packet_size;

    return 0;
}

int simple_table_cleanup(simple_flow_table table) {
    return 0;
}

void simple_table_update_flows(simple_flow_table table, struct timeval now, double ewma_weight) {
    double time_delta;
    double unweighted_rate;

    time_delta = timeval_subtract(now, table->common->last_update);

    if (time_delta <= 0) {
        unweighted_rate = 0;
    } else {
        unweighted_rate = table->common->bytes_since / time_delta;
    }

    table->common->last_inst_rate = table->common->inst_rate;
    table->common->inst_rate = unweighted_rate;

    table->common->last_rate = table->common->rate;

    /* If the rate is zero, then we don't know anything yet.  Don't apply EWMA
     * in that case. */
    if (table->common->rate == 0) {
        table->common->rate = unweighted_rate;
    } else {
        table->common->rate = table->common->rate * ewma_weight +
                              unweighted_rate * (1 - ewma_weight);
    }

    table->common->bytes_since = 0;
    table->common->last_update = now;

    /* We don't track flow rates in this table. (Not suitable for FPS) */
    table->common->max_flow_rate = 0;
}