/* Калибровка каналов: BWlim смешанных размеров, задержка, ограниченный HOLD, DROP и teardown с таймерами. */
#include <stdlib.h>
#include <string.h>
#include "dummynet.h"
#include "test_clock.h"
#include "../lib/platform_compat.h"
#include "../lib/mem.h"

#define CHECK(x) do { if (!(x)) { DEBUG_ERROR(DEBUG_CATEGORY_GENERAL, "FAIL %s:%d: %s", __func__, __LINE__, #x); exit(1); } } while (0)
static struct UASYNC* ua;
static struct dummynet* dn;
static socket_t peers[2];
static struct sockaddr_in proxy;
static unsigned received[2];
static uint64_t bytes[2], last_rx[2];
static uint8_t seen[2][512];

static void setup(unsigned bw, unsigned delay, unsigned capacity) {
    ua = uasync_create(); CHECK(ua);
    dn = dummynet_create(ua, "127.0.0.1", 0); CHECK(dn);
    memset(received, 0, sizeof(received)); memset(bytes, 0, sizeof(bytes)); memset(seen, 0, sizeof(seen));
    memset(&proxy, 0, sizeof(proxy)); proxy.sin_family = AF_INET;
    proxy.sin_addr.s_addr = htonl(INADDR_LOOPBACK); proxy.sin_port = htons(dummynet_get_listen_port(dn));
    for (int i = 0; i < 2; i++) {
        peers[i] = socket_create_udp(AF_INET); CHECK(peers[i] != SOCKET_INVALID);
        struct sockaddr_in address = proxy; address.sin_port = 0;
        CHECK(bind(peers[i], (struct sockaddr*)&address, sizeof(address)) == 0);
        CHECK(socket_set_nonblocking(peers[i]) == 0);
        int size = 4 * 1024 * 1024;
        CHECK(setsockopt(peers[i], SOL_SOCKET, SO_RCVBUF, (const char*)&size, sizeof(size)) == 0);
        CHECK(dummynet_set_direction(dn, 1-i, delay, 0, bw, capacity, 0,
            "127.0.0.1", socket_get_bound_port(peers[i])) == 0);
    }
}

/* Проверяем каждый байт и уникальность независимо от статистики эмулятора. */
static void poll_channels(int timeout) {
    test_clock_poll(ua, timeout);
    for (int i = 0; i < 2; i++) {
        uint8_t data[1500]; ssize_t n;
        while ((n = socket_recvfrom(peers[i], data, sizeof(data), NULL, NULL)) >= 0) {
            CHECK(n >= 4);
            unsigned seq = data[0] | (data[1] << 8); CHECK(seq < 512 && !seen[i][seq]);
            seen[i][seq] = 1;
            for (ssize_t p = 2; p < n; p++) CHECK(data[p] == (uint8_t)(seq + p));
            received[i]++; bytes[i] += n; last_rx[i] = get_time_us();
        }
        CHECK(socket_get_error() == ERR_WOULDBLOCK || socket_get_error() == ERR_AGAIN);
    }
}

static void send_packet(int from, unsigned seq, unsigned size) {
    uint8_t data[1500]; CHECK(size >= 4 && size <= sizeof(data));
    data[0] = seq; data[1] = seq >> 8;
    for (unsigned i = 2; i < size; i++) data[i] = seq + i;
    CHECK(socket_sendto(peers[from], data, size, (struct sockaddr*)&proxy, sizeof(proxy)) == (ssize_t)size);
    poll_channels(0);
}

static void run_for(unsigned ms) {
    uint64_t end = get_time_us() + ms * 1000ULL;
    while (get_time_us() < end) poll_channels(10);
}

static void teardown(void) {
    dummynet_destroy(dn);
    for (int i = 0; i < 2; i++) socket_close_wrapper(peers[i]);
    uasync_poll(ua, 0);
    CHECK(ua->timer_alloc_count == ua->timer_free_count);
    uasync_destroy(ua, 0);
}

static void bandwidth(unsigned bw) {
    setup(bw, 20, 512);
    uint64_t start = get_time_us(), total = 0;
    for (unsigned seq = 0; seq < 256; seq++) {
        unsigned len = seq & 1 ? 1500 : 100;
        total += len;
        send_packet(0, seq, len); send_packet(1, seq, len);
    }
    uint64_t expected = total * 8000 / bw + 20000, end = start + expected + 2000000;
    while ((received[0] < 256 || received[1] < 256) && get_time_us() < end) poll_channels(10);
    for (int i = 0; i < 2; i++) {
        uint64_t elapsed = last_rx[i] - start;
        DEBUG_INFO(DEBUG_CATEGORY_DEBUG, "BW calibration: kbps=%u dir=%d bytes=%llu elapsed_us=%llu expected_us=%llu", bw, i,
            (unsigned long long)bytes[i], (unsigned long long)elapsed, (unsigned long long)expected);
        CHECK(received[i] == 256 && bytes[i] == total);
        CHECK(elapsed * 100 >= expected * 95 && elapsed * 100 <= expected * 105 + 5000);
        const struct dummynet_stats* stats = dummynet_get_stats(dn, 1-i);
        CHECK(stats->sent_bytes == total && !stats->queue_size && !stats->lost && !stats->dropped);
        CHECK(stats->max_queue_delay_us <= elapsed && stats->max_queue_delay_us >= expected - 40000);
    }
    teardown();
}

static void hold_drop(void) {
    setup(80, 20, 8);
    CHECK(dummynet_set_mode(dn, 0, DUMMYNET_HOLD) == 0);
    for (unsigned seq = 0; seq < 12; seq++) send_packet(0, seq, 1000);
    run_for(60);
    const struct dummynet_stats* stats = dummynet_get_stats(dn, 0);
    CHECK(!received[1] && stats->queue_size == 8 && stats->dropped == 4);
    dummynet_reset_stats(dn, 0); CHECK(stats->queue_size == 8 && stats->queue_max == 8);
    uint64_t resumed = get_time_us();
    CHECK(dummynet_set_mode(dn, 0, DUMMYNET_RUN) == 0);
    run_for(50); CHECK(!received[1]);
    run_for(850); CHECK(received[1] == 8 && last_rx[1] - resumed >= 795000);
    // DROP удаляет как delay, так и сериализуемую голову; RUN не возвращает потерянное.
    send_packet(0, 20, 1000); run_for(5);
    CHECK(dummynet_set_mode(dn, 0, DUMMYNET_DROP) == 0);
    send_packet(0, 21, 1000); run_for(50);
    CHECK(stats->blocked == 2 && !stats->queue_size && received[1] == 8);
    CHECK(dummynet_set_mode(dn, 0, DUMMYNET_RUN) == 0);
    send_packet(0, 22, 1000); run_for(25);
    CHECK(dummynet_set_mode(dn, 0, DUMMYNET_DROP) == 0);
    CHECK(stats->blocked == 3 && !stats->queue_size);
    CHECK(dummynet_set_mode(dn, 0, DUMMYNET_RUN) == 0);
    send_packet(0, 23, 1000); run_for(150); CHECK(received[1] == 9);
    // Уничтожение одновременно с delay и shaper: после destroycallbacks не должны обращаться к dn.
    send_packet(0, 24, 1000); run_for(25); send_packet(1, 25, 1000);
    teardown();
    DEBUG_INFO(DEBUG_CATEGORY_DEBUG, "PASS bounded HOLD, paced resume, DROP of pending packets and active teardown");
}

int main(void) {
    debug_config_init(); debug_set_level(DEBUG_LEVEL_ERROR); test_clock_init(10);
    CHECK(socket_platform_init() == 0);
    size_t baseline = u_get_allocated_count();
    bandwidth(2000); CHECK(u_get_allocated_count() == baseline);
    bandwidth(8000); CHECK(u_get_allocated_count() == baseline);
    hold_drop(); CHECK(u_get_allocated_count() == baseline);
    test_clock_finish(); socket_platform_cleanup();
    return 0;
}