#include <math.h>
#include <time.h>
#include "log.h"
#include "shaper.h"
#include "shaper_aqm.h"

thread_local unsigned int seed = 0;
int shaper_aqm_blue_need_drop(uuid_t profile_uuid, struct shaper_aqm_blue_para *para, int curr_queue_len)
{
    time_t curr_time;

    if (time(&curr_time) - para->update_time >= BLUE_FREEZE_TIME) {
        para->update_time = curr_time;
        if (curr_queue_len >= BLUE_QUEUE_LEN_MAX) {
            para->probability = (para->probability + BLUE_INCREMENT) > BLUE_PROBABILITY_MAX ? BLUE_PROBABILITY_MAX : (para->probability + BLUE_INCREMENT);
        } else if (curr_queue_len == 0) {
            para->probability = (para->probability - BLUE_DECREMENT) >= 0 ? (para->probability - BLUE_DECREMENT) : 0;
        }

        LOG_INFO("%s: profile id: %s blue probability update to %d", LOG_TAG_SHAPING, uuid_print_str(profile_uuid), para->probability);
    }

    if (rand_r(&seed) % BLUE_PROBABILITY_MAX < para->probability) {
        return 1;
    }

    return 0;
}

int shaper_aqm_codel_need_drop(uuid_t profile_uuid, struct shaper_aqm_codel_para *para, unsigned long long curr_time_ms, unsigned long long latency_ms)
{
    if (latency_ms < CODEL_MAX_LATENCY) {
        if (para->state != CODEL_STATE_NORMAL) {
            para->state = CODEL_STATE_NORMAL;
            LOG_INFO("%s: profile id: %s codel enter state CODEL_STATE_NORMAL, last DROPPING_PHASE drop count %d", LOG_TAG_SHAPING, uuid_print_str(profile_uuid), para->drop_count);
        }
        
        return 0;
    } 

    int ret = 0;
    switch (para->state) {
        case CODEL_STATE_NORMAL:
            para->start_drop_time_ms = curr_time_ms + CODEL_DROP_INTERVAL;
            para->state = CODEL_STATE_DROPPING_TIMER;
            LOG_INFO("%s: profile id: %s codel enter state CODEL_STATE_DROPPING_TIMER", LOG_TAG_SHAPING, uuid_print_str(profile_uuid));
            break;
        case CODEL_STATE_DROPPING_TIMER:
            if (curr_time_ms >= para->start_drop_time_ms) {
                para->state = CODEL_STATE_DROPPING_PHASE;
                para->drop_count = 1;
                para->next_drop_time_ms = curr_time_ms + CODEL_DROP_INTERVAL / sqrt(para->drop_count);
                ret = 1;
                LOG_INFO("%s: profile id: %s codel enter state CODEL_STATE_DROPPING_PHASE", LOG_TAG_SHAPING, uuid_print_str(profile_uuid));
            }
            break;
        case CODEL_STATE_DROPPING_PHASE:
            if (curr_time_ms >= para->next_drop_time_ms) {
                para->drop_count++;
                para->next_drop_time_ms = curr_time_ms + CODEL_DROP_INTERVAL / sqrt(para->drop_count);
                ret = 1;
            }
            break;
        default:
            break;
    }

    return ret;
}


static int shaper_aqm_have_processed(struct shaping_packet_wrapper *pkt_wrapper, uuid_t profile_uuid)
{
    int i = 0;

    for (i = 0; i < SHAPING_REF_PROFILE_NUM_MAX; i++) {
        if (uuid_compare(profile_uuid, pkt_wrapper->aqm_processed_pf_uuids[i]) == 0) {
            return 1;
        } else if (uuid_is_null(pkt_wrapper->aqm_processed_pf_uuids[i])) {
            break;
        }
    }

    return 0;
}

static void shaper_aqm_mark_processed(struct shaping_packet_wrapper *pkt_wrapper, uuid_t profile_uuid)
{
    int i = 0;

    for (i = 0; i < SHAPING_REF_PROFILE_NUM_MAX; i++) {
        if (uuid_is_null(pkt_wrapper->aqm_processed_pf_uuids[i])) {
            uuid_copy(pkt_wrapper->aqm_processed_pf_uuids[i], profile_uuid);
            break;
        }
    }
}

int shaper_aqm_need_drop(struct shaping_profile_info *profile, struct shaping_packet_wrapper *pkt_wrapper, enum shaping_packet_dir dir, struct timespec *curr_time, unsigned long long latency_us)
{
    int ret = 0;
    unsigned long long curr_time_ms;
    
    if (profile->hash_node->aqm_type == AQM_TYPE_NONE) {
        return 0;
    }

    if (shaper_aqm_have_processed(pkt_wrapper, profile->uuid)) {
        return 0;
    }
    
    switch (profile->hash_node->aqm_type) {
        case AQM_TYPE_BLUE:
            ret = shaper_aqm_blue_need_drop(profile->uuid, &profile->hash_node->aqm_blue_para, profile->hash_node->queue_len[profile->priority][dir]);
            break;
        case AQM_TYPE_CODEL:
            curr_time_ms = curr_time->tv_sec * MILLI_SECONDS_PER_SEC + curr_time->tv_nsec / NANO_SECONDS_PER_MILLI_SEC;
            ret = shaper_aqm_codel_need_drop(profile->uuid, &profile->hash_node->aqm_codel_para, curr_time_ms, latency_us / 1000);
            break;
        default:
            break;
    }

    shaper_aqm_mark_processed(pkt_wrapper, profile->uuid);

    return ret;
}