// test_etcp_router_unit.c — Юнит-тест etcp_router: reorder, seq, ACK, conn lifecycle
// Без ETCP-соединений, без сокетов, без BGP.
// Инжектит SVC_ROUTE пакеты напрямую через etcp_router_recv_cb из api_bindings.
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
#include <sys/time.h>

#include "../src/etcp.h"
#include "../src/etcp_api.h"
#include "../src/etcp_router.h"
#include "../src/utun_instance.h"
#include "../lib/u_async.h"
#include "../lib/ll_queue.h"
#include "../lib/debug_config.h"
#include "../lib/mem.h"

#define TEST_SVC_ID 0x42
#define TEST_SVC_ID2 0x43
#define TEST_REMOTE_NODE 0xAAAA000000000001ULL
#define TEST_REMOTE_NODE2 0xAAAA000000000002ULL

// ======================== Test handler state ========================
static struct {
    int delivered;
    int errors;
    uint32_t expected_seq;
    uint32_t last_seq;
    uint8_t marker;
} rx;

static int g_notify_count = 0;

static void test_handler(struct ETCP_CONN* conn, struct ll_entry* entry) {
    (void)conn;
    if (!entry || !entry->dgram || entry->len < 2) {
        g_notify_count++;
        if (entry) { queue_dgram_free(entry); queue_entry_free(entry); }
        return;
    }
    // close/restart: len==9 (svc_id + node_id), conn==NULL
    if (entry->len == 9 && !conn) {
        g_notify_count++;
        queue_dgram_free(entry); queue_entry_free(entry);
        return;
    }
    if (entry->dgram[1] != rx.marker) { rx.errors++; } else { rx.delivered++; rx.last_seq = rx.expected_seq; rx.expected_seq++; }
    queue_entry_free(entry); queue_dgram_free(entry);
}

static void rx_reset(uint8_t marker) {
    memset(&rx, 0, sizeof(rx));
    rx.marker = marker;
}

// ======================== Inject helper ========================
static struct ETCP_CONN fake_conn;

static void inject(etcp_recv_fn recv_cb, struct UTUN_INSTANCE* inst,
                   uint64_t src, uint8_t svc_id, uint32_t seq,
                   const uint8_t* pl, size_t pl_len, int is_ack, uint8_t flags) {
    struct SVC_ROUTE_HDR hdr;
    memset(&hdr, 0, sizeof(hdr));
    hdr.cmd         = ETCP_ID_SVC_ROUTE;
    hdr.dst_node_id = inst->node_id;
    hdr.src_node_id = src;
    hdr.seq         = seq;
    hdr.svc_id      = svc_id;
    hdr.flags       = flags;

    size_t total = SVC_ROUTE_HDR_SIZE + (is_ack ? 0 : pl_len);
    struct ll_entry* e = queue_entry_new(0);
    if (!e) { printf("  inject: queue_entry_new failed\n"); return; }
    e->dgram = u_malloc(total);
    if (!e->dgram) { queue_entry_free(e); return; }
    memcpy(e->dgram, &hdr, SVC_ROUTE_HDR_SIZE);
    if (!is_ack && pl_len > 0)
        memcpy(e->dgram + SVC_ROUTE_HDR_SIZE, pl, pl_len);
    e->len = total;

    recv_cb(&fake_conn, e);
}

// ======================== Setup ========================
#define SETUP() do { \
    ua = uasync_create(); \
    if (!ua) { printf("  SETUP: uasync_create failed\n"); return -1; } \
    memset(&inst, 0, sizeof(inst)); \
    inst.ua = ua; \
    inst.node_id = 0xBBBB000000000001ULL; \
    debug_config_init(); \
    debug_set_level(DEBUG_LEVEL_ERROR); \
    debug_set_categories(DEBUG_CATEGORY_ALL); \
    memset(&fake_conn, 0, sizeof(fake_conn)); \
    fake_conn.instance = &inst; \
    TESTASSERT(etcp_router_init(&inst) == 0); \
    TESTASSERT(etcp_router_bind(&inst, TEST_SVC_ID, test_handler) == 0); \
    recv_cb = inst.api_bindings.callbacks[ETCP_ID_SVC_ROUTE]; \
    TESTASSERT(recv_cb != NULL); \
} while(0)

#define TEARDOWN() do { \
    etcp_router_destroy(&inst); \
    uasync_destroy(ua, 0); \
    ua = NULL; \
} while(0)

// ======================== Macros ========================
static int test_total = 0, test_passed = 0, test_failed = 0;

#define TESTASSERT(cond) do { \
    if (!(cond)) { printf("  FAIL: %s:%d — %s\n", __FILE__, __LINE__, #cond); return -1; } \
} while(0)

#define TEST(name) do { \
    test_total++; \
    printf("TEST %d: %-50s ", test_total, name); fflush(stdout); \
} while(0)

#define PASS() do { puts("PASS"); test_passed++; } while(0)
#define FAIL(msg) do { printf("FAIL: %s\n", msg); test_failed++; return -1; } while(0)

// ======================== Tests ========================

static int test_init_destroy(void) {
    TEST("init/destroy");
    struct UASYNC* ua = uasync_create();
    if (!ua) FAIL("uasync_create");
    struct UTUN_INSTANCE inst;
    memset(&inst, 0, sizeof(inst));
    inst.ua = ua;
    inst.node_id = 1;
    debug_config_init();
    debug_set_level(DEBUG_LEVEL_ERROR);
    debug_set_categories(DEBUG_CATEGORY_ALL);

    memset(&fake_conn, 0, sizeof(fake_conn));
    fake_conn.instance = &inst;

    if (etcp_router_init(&inst) != 0) FAIL("init");
    if (inst.router_conns == NULL) FAIL("router_conns NULL after init");
    if (inst.api_bindings.callbacks[ETCP_ID_SVC_ROUTE] == NULL) FAIL("recv_cb not bound");

    etcp_router_destroy(&inst);
    if (inst.router_conns != NULL) FAIL("router_conns not NULL after destroy");
    if (inst.api_bindings.callbacks[ETCP_ID_SVC_ROUTE] != NULL) FAIL("recv_cb still bound");

    uasync_destroy(ua, 0);
    PASS();
    return 0;
}

static int test_bind_unbind(void) {
    TEST("bind/unbind API");
    struct UASYNC* ua = uasync_create();
    struct UTUN_INSTANCE inst;
    memset(&inst, 0, sizeof(inst));
    inst.ua = ua;
    inst.node_id = 1;
    debug_config_init();
    debug_set_level(DEBUG_LEVEL_ERROR);
    debug_set_categories(DEBUG_CATEGORY_ALL);

    if (etcp_router_init(&inst) != 0) FAIL("init");

    // bind
    if (etcp_router_bind(&inst, 0xEE, test_handler) != 0) FAIL("bind");
    if (inst.router_bindings.callbacks[0xEE] != test_handler) FAIL("cb not set");
    // rebind (overwrite)
    if (etcp_router_bind(&inst, 0xEE, test_handler) != 0) FAIL("rebind");
    // unbind
    if (etcp_router_unbind(&inst, 0xEE) != 0) FAIL("unbind");
    if (inst.router_bindings.callbacks[0xEE] != NULL) FAIL("cb not cleared");
    // double unbind
    if (etcp_router_unbind(&inst, 0xEE) == 0) FAIL("double unbind should fail");
    // null args
    if (etcp_router_bind(NULL, 0, test_handler) == 0) FAIL("bind null inst");
    etcp_router_destroy(&inst);
    uasync_destroy(ua, 0);
    PASS();
    return 0;
}

static int test_conn_get_create(void) {
    TEST("conn_get — create");
    struct UASYNC* ua; struct UTUN_INSTANCE inst; etcp_recv_fn recv_cb;
    SETUP();

    struct ETCP_ROUTER_CONN* c = etcp_router_conn_get(&inst, TEST_REMOTE_NODE, TEST_SVC_ID);
    if (!c) FAIL("conn_get returned NULL");
    if (c->remote_node_id != TEST_REMOTE_NODE) FAIL("wrong remote_node_id");
    if (c->svc_id != TEST_SVC_ID) FAIL("wrong svc_id");
    if (c->tx_seq != 0) FAIL("tx_seq != 0");
    if (c->rx_seq != 0) FAIL("rx_seq != 0");
    if (c->tx_acked != 0) FAIL("tx_acked != 0");
    if (c->last_sent_ack_seq != 0) FAIL("last_sent_ack_seq != 0");
    if (c->recv_q == NULL) FAIL("recv_q is NULL");
    if (c->last_dgram_ts == 0) FAIL("last_dgram_ts not set");
    if (c->ack_timer != NULL) FAIL("ack_timer set at creation");

    etcp_router_conn_close(c);
    TEARDOWN();
    PASS();
    return 0;
}

static int test_conn_get_reuse(void) {
    TEST("conn_get — reuse / different");
    struct UASYNC* ua; struct UTUN_INSTANCE inst; etcp_recv_fn recv_cb;
    SETUP();

    struct ETCP_ROUTER_CONN* c1 = etcp_router_conn_get(&inst, TEST_REMOTE_NODE, TEST_SVC_ID);
    if (!c1) FAIL("c1 NULL");
    struct ETCP_ROUTER_CONN* c2 = etcp_router_conn_get(&inst, TEST_REMOTE_NODE, TEST_SVC_ID);
    if (c1 != c2) FAIL("reuse: different pointers");

    struct ETCP_ROUTER_CONN* c3 = etcp_router_conn_get(&inst, TEST_REMOTE_NODE2, TEST_SVC_ID);
    if (c3 == c1) FAIL("different remote, same pointer");
    struct ETCP_ROUTER_CONN* c4 = etcp_router_conn_get(&inst, TEST_REMOTE_NODE, TEST_SVC_ID2);
    if (c4 == c1) FAIL("different svc, same pointer");

    etcp_router_conn_close(c1);
    etcp_router_conn_close(c3);
    etcp_router_conn_close(c4);
    TEARDOWN();
    PASS();
    return 0;
}

static int test_conn_close(void) {
    TEST("conn_close — new after close");
    struct UASYNC* ua; struct UTUN_INSTANCE inst; etcp_recv_fn recv_cb;
    SETUP();

    struct ETCP_ROUTER_CONN* c1 = etcp_router_conn_get(&inst, TEST_REMOTE_NODE, TEST_SVC_ID);
    if (!c1) FAIL("c1 NULL");
    c1->tx_seq = 99; // mark
    etcp_router_conn_close(c1);
    struct ETCP_ROUTER_CONN* c2 = etcp_router_conn_get(&inst, TEST_REMOTE_NODE, TEST_SVC_ID);
    if (!c2) FAIL("c2 NULL");
    if (c2->tx_seq != 0 || c2->rx_seq != 0) FAIL("not fresh after close+reopen");

    etcp_router_conn_close(c2);
    TEARDOWN();
    PASS();
    return 0;
}

// ======================== Seq/reorder tests ========================

static int test_in_order(void) {
    TEST("in-order delivery (seq 0,1,2)");
    struct UASYNC* ua; struct UTUN_INSTANCE inst; etcp_recv_fn recv_cb;
    SETUP();
    struct ETCP_ROUTER_CONN* c = etcp_router_conn_get(&inst, TEST_REMOTE_NODE, TEST_SVC_ID);
    if (!c) FAIL("conn_get failed");

    rx_reset(0xAA);
    uint8_t data[] = { TEST_SVC_ID, 0xAA, 0 };
    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 0, data + 1, 2, 0, 0);
    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 1, data + 1, 2, 0, 0);
    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 2, data + 1, 2, 0, 0);

    if (rx.delivered != 3) FAIL("delivered != 3");
    if (rx.errors != 0) FAIL("errors != 0");
    if (c->rx_seq != 3) FAIL("rx_seq != 3");

    etcp_router_conn_close(c);
    TEARDOWN();
    PASS();
    return 0;
}

static int test_out_of_order(void) {
    TEST("out-of-order (0,2,3 then 1 → assembly to 3)");
    struct UASYNC* ua; struct UTUN_INSTANCE inst; etcp_recv_fn recv_cb;
    SETUP();
    struct ETCP_ROUTER_CONN* c = etcp_router_conn_get(&inst, TEST_REMOTE_NODE, TEST_SVC_ID);
    if (!c) FAIL("conn_get failed");

    rx_reset(0xBB);
    uint8_t data[] = { TEST_SVC_ID, 0xBB, 0 };
    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 0, data + 1, 2, 0, 0);
    if (rx.delivered != 1) FAIL("after seq 0: delivered != 1");
    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 2, data + 1, 2, 0, 0);
    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 3, data + 1, 2, 0, 0);
    if (rx.delivered != 1) FAIL("after seq 2,3: still delivered != 1 (gap at 1)");

    // Fill the gap
    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 1, data + 1, 2, 0, 0);
    if (rx.delivered != 4) FAIL("after seq 1 fill: delivered != 4");
    if (rx.errors   != 0) FAIL("errors != 0");
    if (c->rx_seq   != 4) FAIL("rx_seq != 4");

    etcp_router_conn_close(c);
    TEARDOWN();
    PASS();
    return 0;
}

static int test_duplicate_same(void) {
    TEST("duplicate — same seq injected twice");
    struct UASYNC* ua; struct UTUN_INSTANCE inst; etcp_recv_fn recv_cb;
    SETUP();
    struct ETCP_ROUTER_CONN* c = etcp_router_conn_get(&inst, TEST_REMOTE_NODE, TEST_SVC_ID);
    if (!c) FAIL("conn_get failed");

    rx_reset(0xCC);
    uint8_t data[] = { TEST_SVC_ID, 0xCC, 0 };
    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 0, data + 1, 2, 0, 0);
    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 1, data + 1, 2, 0, 0);
    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 1, data + 1, 2, 0, 0); // dup

    if (rx.delivered != 2) FAIL("delivered != 2 (dup dropped)");
    if (c->rx_seq   != 2) FAIL("rx_seq != 2");

    etcp_router_conn_close(c);
    TEARDOWN();
    PASS();
    return 0;
}

static int test_duplicate_past(void) {
    TEST("duplicate — past seq (already delivered)");
    struct UASYNC* ua; struct UTUN_INSTANCE inst; etcp_recv_fn recv_cb;
    SETUP();
    struct ETCP_ROUTER_CONN* c = etcp_router_conn_get(&inst, TEST_REMOTE_NODE, TEST_SVC_ID);
    if (!c) FAIL("conn_get failed");

    rx_reset(0xDD);
    uint8_t data[] = { TEST_SVC_ID, 0xDD, 0 };
    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 0, data + 1, 2, 0, 0);
    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 1, data + 1, 2, 0, 0);
    if (rx.delivered != 2) FAIL("delivered != 2");
    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 0, data + 1, 2, 0, 0); // past

    if (rx.delivered != 2) FAIL("delivered != 2 (past dup dropped)");
    if (c->rx_seq   != 2) FAIL("rx_seq != 2");

    etcp_router_conn_close(c);
    TEARDOWN();
    PASS();
    return 0;
}

static int test_out_of_bounds(void) {
    TEST("out of bounds — seq too far ahead");
    struct UASYNC* ua; struct UTUN_INSTANCE inst; etcp_recv_fn recv_cb;
    SETUP();
    struct ETCP_ROUTER_CONN* c = etcp_router_conn_get(&inst, TEST_REMOTE_NODE, TEST_SVC_ID);
    if (!c) FAIL("conn_get failed");

    rx_reset(0xEE);
    uint8_t data[] = { TEST_SVC_ID, 0xEE, 0 };
    uint32_t bad_seq = ROUTER_MAX_INFLIGHT + 2;
    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, bad_seq, data + 1, 2, 0, 0);

    if (rx.delivered != 0) FAIL("out-of-bounds delivered");
    if (c->rx_seq   != 0) FAIL("rx_seq changed on bounds drop");

    etcp_router_conn_close(c);
    TEARDOWN();
    PASS();
    return 0;
}

static int test_circular_wrap(void) {
    TEST("32-bit circular wrap-around");
    struct UASYNC* ua; struct UTUN_INSTANCE inst; etcp_recv_fn recv_cb;
    SETUP();
    struct ETCP_ROUTER_CONN* c = etcp_router_conn_get(&inst, TEST_REMOTE_NODE, TEST_SVC_ID);
    if (!c) FAIL("conn_get failed");

    c->rx_seq = 0xFFFFFFFE;
    rx_reset(0x11);
    rx.expected_seq = 0xFFFFFFFE;
    uint8_t data[] = { TEST_SVC_ID, 0x11, 0 };
    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 0xFFFFFFFE, data + 1, 2, 0, 0);
    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 0xFFFFFFFF, data + 1, 2, 0, 0);
    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 0,            data + 1, 2, 0, 0);
    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 1,            data + 1, 2, 0, 0);

    if (rx.delivered != 4) FAIL("delivered != 4 (wrap)");
    if (c->rx_seq   != 2) FAIL("rx_seq != 2 after wrap (wrapped)");

    etcp_router_conn_close(c);
    TEARDOWN();
    PASS();
    return 0;
}

static int test_data_integrity(void) {
    TEST("data integrity — payload preserved");
    struct UASYNC* ua; struct UTUN_INSTANCE inst; etcp_recv_fn recv_cb;
    SETUP();
    struct ETCP_ROUTER_CONN* c = etcp_router_conn_get(&inst, TEST_REMOTE_NODE, TEST_SVC_ID);
    if (!c) FAIL("conn_get failed");

    rx_reset(0x77);
    uint8_t payload[10] = { 0x77, 0xA1, 0xB2, 0xC3, 0xD4, 0xE5, 0xF6, 0x07, 0x18, 0x29 };
    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 0, payload, 10, 0, 0);

    if (rx.delivered != 1) FAIL("delivered != 1");
    if (rx.errors   != 0) FAIL("data mismatch");

    etcp_router_conn_close(c);
    TEARDOWN();
    PASS();
    return 0;
}

static int test_ack_receive(void) {
    TEST("ACK receive — tx_acked updated");
    struct UASYNC* ua; struct UTUN_INSTANCE inst; etcp_recv_fn recv_cb;
    SETUP();
    struct ETCP_ROUTER_CONN* c = etcp_router_conn_get(&inst, TEST_REMOTE_NODE, TEST_SVC_ID);
    if (!c) FAIL("conn_get failed");

    rx_reset(0x00);
    // Send ACK: is_ack=1, seq=7 means remote has rx_seq=7
    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 7, NULL, 0, 1, 0);

    if (c->tx_acked != 7)      FAIL("tx_acked not updated from ACK");
    if (rx.delivered != 0)     FAIL("ACK delivered to handler (should not)");
    if (c->last_dgram_ts == 0) FAIL("last_dgram_ts not updated on ACK");

    etcp_router_conn_close(c);
    TEARDOWN();
    PASS();
    return 0;
}

static int test_ack_timer(void) {
    TEST("ACK timer scheduled on data receive");
    struct UASYNC* ua; struct UTUN_INSTANCE inst; etcp_recv_fn recv_cb;
    SETUP();
    struct ETCP_ROUTER_CONN* c = etcp_router_conn_get(&inst, TEST_REMOTE_NODE, TEST_SVC_ID);
    if (!c) FAIL("conn_get failed");

    if (c->ack_timer != NULL) FAIL("ack_timer set before any data");

    rx_reset(0x55);
    uint8_t data[] = { TEST_SVC_ID, 0x55, 0 };
    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 0, data + 1, 2, 0, 0);

    if (c->ack_timer == NULL && c->last_sent_ack_seq != 1) FAIL("ack not sent (no timer, no immediate)");
    if (c->ack_timer != NULL && c->last_sent_ack_seq != 0) FAIL("last_sent_ack_seq changed before timer fired");

    // Cancel timer manually (it would fire in real event loop)
    if (c->ack_timer) uasync_cancel_timeout(ua, c->ack_timer);
    c->ack_timer = NULL;

    etcp_router_conn_close(c);
    TEARDOWN();
    PASS();
    return 0;
}

static int test_send_q(void) {
    TEST("send_q — inflight full queues, not lost");
    struct UASYNC* ua; struct UTUN_INSTANCE inst; etcp_recv_fn recv_cb;
    SETUP();
    struct ETCP_ROUTER_CONN* c = etcp_router_conn_get(&inst, TEST_REMOTE_NODE, TEST_SVC_ID);
    if (!c) FAIL("conn_get failed");

    // Simulate full inflight: set tx_acked far behind tx_seq
    c->tx_seq = ROUTER_MAX_INFLIGHT;
    c->tx_acked = 0;
    if (c->send_q == NULL) FAIL("send_q is NULL");

    // Send via conn_send — should queue, not drop
    uint8_t data[4] = { 1, 2, 3, 4 };
    int ret = etcp_router_conn_send(c, data, sizeof(data));
    if (ret != 0) FAIL("conn_send should return 0 (queued in send_q)");
    if (c->send_blocked == 0) FAIL("send_blocked not set");
    if (c->send_resume_timer == NULL) FAIL("send_resume_timer not set");
    if (queue_entry_count(c->send_q) != 1) FAIL("send_q count != 1");
    if (c->tx_seq != ROUTER_MAX_INFLIGHT) FAIL("tx_seq advanced while queued");

    // Cancel timers manually
    if (c->send_resume_timer) { uasync_cancel_timeout(ua, c->send_resume_timer); c->send_resume_timer = NULL; }

    etcp_router_conn_close(c);
    TEARDOWN();
    PASS();
    return 0;
}

static int test_loopback(void) {
    TEST("loopback — etcp_route_send to self");
    struct UASYNC* ua; struct UTUN_INSTANCE inst; etcp_recv_fn recv_cb;
    SETUP();

    rx_reset(0x66);
    uint8_t buf[4] = { TEST_SVC_ID, 0x66, 0x00, 0x00 };
    struct ll_entry* e = queue_entry_new(0);
    if (!e) FAIL("queue_entry_new");
    e->dgram = u_malloc(4);
    if (!e->dgram) { queue_entry_free(e); FAIL("u_malloc"); }
    memcpy(e->dgram, buf, 4);
    e->len = 4;

    if (etcp_route_send(&inst, inst.node_id, e) != 0) FAIL("loopback send failed");
    if (rx.delivered != 1) FAIL("loopback not delivered");
    if (rx.errors   != 0) FAIL("loopback data mismatch");

    TEARDOWN();
    PASS();
    return 0;
}

static int test_timestamp(void) {
    TEST("last_dgram_ts updated on data");
    struct UASYNC* ua; struct UTUN_INSTANCE inst; etcp_recv_fn recv_cb;
    SETUP();
    struct ETCP_ROUTER_CONN* c = etcp_router_conn_get(&inst, TEST_REMOTE_NODE, TEST_SVC_ID);
    if (!c) FAIL("conn_get failed");

    uint16_t before = c->last_dgram_ts;

    rx_reset(0x99);
    uint8_t data[] = { TEST_SVC_ID, 0x99, 0 };
    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 0, data + 1, 2, 0, 0);

    if (c->last_dgram_ts == 0) FAIL("last_dgram_ts zero after data");
    // Cancel ack_timer
    if (c->ack_timer) { uasync_cancel_timeout(ua, c->ack_timer); c->ack_timer = NULL; }

    etcp_router_conn_close(c);
    TEARDOWN();
    PASS();
    return 0;
}

static int test_conn_send_no_bgp(void) {
    TEST("conn_send — no BGP returns error");
    struct UASYNC* ua; struct UTUN_INSTANCE inst; etcp_recv_fn recv_cb;
    SETUP();
    struct ETCP_ROUTER_CONN* c = etcp_router_conn_get(&inst, TEST_REMOTE_NODE, TEST_SVC_ID);
    if (!c) FAIL("conn_get failed");

    uint8_t data[4] = { 1, 2, 3, 4 };
    int ret = etcp_router_conn_send(c, data, sizeof(data));
    if (ret == 0) FAIL("conn_send should fail without BGP");

    etcp_router_conn_close(c);
    TEARDOWN();
    PASS();
    return 0;
}

// ======================== Helper: pump random data ========================
static int pump_data(etcp_recv_fn recv_cb, struct UTUN_INSTANCE* inst,
                     uint8_t marker, int count, uint8_t flags) {
    uint8_t data[] = { TEST_SVC_ID, marker, 0 };
    for (int i = 0; i < count; i++)
        inject(recv_cb, inst, TEST_REMOTE_NODE, TEST_SVC_ID, i, data + 1, 2, 0, flags);
    return count;
}

// ======================== Restart/session tests ========================

static int test_rst_flag(void) {
    TEST("RST flag — rconn destroyed, service notified");
    struct UASYNC* ua; struct UTUN_INSTANCE inst; etcp_recv_fn recv_cb;
    SETUP();
    g_notify_count = 0;

    int n = rand() % 10 + 1;
    rx_reset(0xA1);
    pump_data(recv_cb, &inst, 0xA1, n, 0);
    if (rx.delivered != n) FAIL("initial pump failed");

    uint8_t data[] = { TEST_SVC_ID, 0x01, 0 };
    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, n, data + 1, 2, 0, ROUTER_FLAG_RST);
    if (g_notify_count != 1) FAIL("RST should notify service");

    struct ETCP_ROUTER_CONN* c = etcp_router_conn_get(&inst, TEST_REMOTE_NODE, TEST_SVC_ID);
    if (!c) FAIL("new rconn should exist");
    etcp_router_conn_close(c);

    TEARDOWN();
    PASS();
    return 0;
}

static int test_client_restart(void) {
    TEST("client restart — START flag detected after random data");
    struct UASYNC* ua; struct UTUN_INSTANCE inst; etcp_recv_fn recv_cb;
    SETUP();
    g_notify_count = 0;

    int n = rand() % 10 + 1;
    rx_reset(0xB1);
    pump_data(recv_cb, &inst, 0xB1, n, 0);
    if (rx.delivered != n) FAIL("initial pump failed");

    rx_reset(0xB2);
    uint8_t data[] = { TEST_SVC_ID, 0xB2, 0 };
    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 0, data + 1, 2, 0, ROUTER_FLAG_START);
    if (g_notify_count != 1) FAIL("restart not notified");
    if (rx.delivered < 1) FAIL("data after restart not delivered");

    TEARDOWN();
    PASS();
    return 0;
}

static int test_sess_id_change(void) {
    TEST("sess_id change — 0→1 with START triggers restart");
    struct UASYNC* ua; struct UTUN_INSTANCE inst; etcp_recv_fn recv_cb;
    SETUP();
    g_notify_count = 0;

    int n = rand() % 10 + 1;
    rx_reset(0xC1);
    pump_data(recv_cb, &inst, 0xC1, n, 0);
    if (rx.delivered != n) FAIL("initial pump failed");

    rx_reset(0xC2);
    uint8_t data[] = { TEST_SVC_ID, 0xC2, 0 };
    uint8_t f = (1 << ROUTER_SESS_ID_SHIFT) | ROUTER_FLAG_START;
    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 0, data + 1, 2, 0, f);
    if (g_notify_count != 1) FAIL("restart not notified");
    if (rx.delivered < 1) FAIL("data after restart not delivered");

    TEARDOWN();
    PASS();
    return 0;
}

static int test_sess_id_wrap(void) {
    TEST("sess_id wrap — 3→0 with START triggers restart");
    struct UASYNC* ua; struct UTUN_INSTANCE inst; etcp_recv_fn recv_cb;
    SETUP();
    g_notify_count = 0;

    int n = rand() % 10 + 1;
    uint8_t f3 = (3 << ROUTER_SESS_ID_SHIFT);
    rx_reset(0xD1);

    struct ETCP_ROUTER_CONN* c = etcp_router_conn_get(&inst, TEST_REMOTE_NODE, TEST_SVC_ID);
    if (!c) FAIL("rconn not found");
    c->peer_sess_id = 3;

    pump_data(recv_cb, &inst, 0xD1, n, f3);
    if (rx.delivered != n) FAIL("initial pump failed");

    rx_reset(0xD2);
    g_notify_count = 0;
    uint8_t data[] = { TEST_SVC_ID, 0xD2, 0 };
    uint8_t f0 = (0 << ROUTER_SESS_ID_SHIFT) | ROUTER_FLAG_START;
    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 0, data + 1, 2, 0, f0);
    if (g_notify_count != 1) FAIL("restart not notified on wrap");
    if (rx.delivered < 1) FAIL("data after wrap not delivered");

    TEARDOWN();
    PASS();
    return 0;
}

static int test_server_reinit(void) {
    TEST("server reinit — new rconn gets start_sent=0 sess_id=0");
    struct UASYNC* ua; struct UTUN_INSTANCE inst; etcp_recv_fn recv_cb;
    SETUP();

    int n = rand() % 10 + 1;
    pump_data(recv_cb, &inst, 0xE1, n, 0);

    etcp_router_destroy(&inst);
    memset(&inst.api_bindings, 0, sizeof(inst.api_bindings));
    memset(&inst.router_bindings, 0, sizeof(inst.router_bindings));
    if (etcp_router_init(&inst) != 0) FAIL("reinit failed");
    etcp_router_bind(&inst, TEST_SVC_ID, test_handler);
    recv_cb = inst.api_bindings.callbacks[ETCP_ID_SVC_ROUTE];
    if (!recv_cb) FAIL("recv_cb not bound");

    struct ETCP_ROUTER_CONN* c = etcp_router_conn_get(&inst, TEST_REMOTE_NODE, TEST_SVC_ID);
    if (!c) FAIL("rconn after reinit");
    if (c->start_sent != 0) FAIL("start_sent != 0 after reinit");
    if (c->sess_id != 0) FAIL("sess_id != 0 after reinit");

    etcp_router_conn_close(c);
    TEARDOWN();
    PASS();
    return 0;
}

// ======================== Main ========================
int main(void) {
    // Run all tests
    test_init_destroy();
    test_bind_unbind();
    test_conn_get_create();
    test_conn_get_reuse();
    test_conn_close();
    test_in_order();
    test_out_of_order();
    test_duplicate_same();
    test_duplicate_past();
    test_out_of_bounds();
    test_circular_wrap();
    test_data_integrity();
    test_ack_receive();
    test_ack_timer();
    test_send_q();
    test_loopback();
    test_timestamp();
    test_conn_send_no_bgp();
    test_rst_flag();
    test_client_restart();
    test_sess_id_change();
    test_sess_id_wrap();
    test_server_reinit();

    printf("\n=== Results: %d/%d passed, %d failed ===\n", test_passed, test_total, test_failed);
    return test_failed > 0 ? 1 : 0;
}