// test_stcp.c — comprehensive STCP integration tests
#include "stcp.h"
#include "stcp_server.h"
#include "stcp_client.h"
#include "secure_channel.h"
#include "../lib/u_async.h"
#include "../lib/ll_queue.h"
#include "../lib/debug_config.h"
#include "../lib/mem.h"
#include "../lib/socket_compat.h"
#include <stdio.h>
#include <string.h>
#include <stdlib.h>

static int tests_passed = 0, tests_total = 0;
static struct SC_MYKEYS s_keys, c_keys;

#define BASE_PORT 23456

#define TASSERT(cond) do { \
    if (!(cond)) { DEBUG_ERROR(DEBUG_CATEGORY_GENERAL, "  FAIL: %s", #cond); return 1; } \
} while(0)

#define TRUN(name) do { \
    tests_total++; \
    DEBUG_INFO(DEBUG_CATEGORY_GENERAL, "--- %s ---", name); \
    int _r = name(); \
    if (_r == 0) { tests_passed++; DEBUG_INFO(DEBUG_CATEGORY_GENERAL, "  PASS"); } \
} while(0)

// ======================= peer helper =======================

struct test_peer {
    struct stcp_conn *conn;
    struct ll_queue *rx, *tx;
    int ready, closed, close_err, msg_count;
    uint8_t *accum;
    size_t accum_len, accum_cap;
};

static void peer_rx_cb(struct ll_queue *q, void *arg) {
    struct test_peer *p = (struct test_peer *)arg;
    struct ll_entry *e = queue_data_get(q);
    if (!e) { queue_resume_callback(q); return; }
    p->msg_count++;
    size_t need = p->accum_len + e->len;
    if (need > p->accum_cap) { p->accum_cap = need + 4096; p->accum = u_realloc(p->accum, p->accum_cap); }
    memcpy(p->accum + p->accum_len, e->dgram, e->len);
    p->accum_len += e->len;
    queue_entry_free(e);
    queue_resume_callback(q);
    if (p->conn) stcp_rx_resume_if_needed(p->conn);
}

static void peer_close_cb(struct stcp_conn *conn, int err, void *arg) {
    (void)conn;
    struct test_peer *p = (struct test_peer *)arg;
    p->closed = 1; p->close_err = err;
}

static void setup_peer(struct test_peer *p, struct stcp_conn *conn) {
    p->conn = conn;
    p->rx = queue_new(conn->ua, 0, 0, 0, "rx");
    p->tx = queue_new(conn->ua, 0, 0, 0, "tx");
    queue_set_threshold(p->rx, STCP_RX_QUEUE_MAX_PACKETS, STCP_RX_QUEUE_MAX_BYTES);
    queue_set_callback(p->rx, peer_rx_cb, p);
    stcp_conn_set_rx_queue(conn, p->rx);
    stcp_conn_set_tx_queue(conn, p->tx);
    p->ready = 1;
}

static void server_connect_cb(struct stcp_conn *conn, void *arg) {
    struct test_peer *p = (struct test_peer *)arg;
    setup_peer(p, conn);
}

static void client_ready_cb(struct stcp_conn *conn, void *arg) {
    struct test_peer *p = (struct test_peer *)arg;
    setup_peer(p, conn);
}

static void peer_cleanup(struct test_peer *p) {
    if (p->rx) { queue_free(p->rx); p->rx = NULL; }
    if (p->tx) { queue_free(p->tx); p->tx = NULL; }
    if (p->accum) { u_free(p->accum); p->accum = NULL; }
}

static int peer_send(struct test_peer *p, const uint8_t *data, size_t len) {
    struct ll_entry *e = queue_entry_new(0);
    if (!e) return -1;
    e->dgram = u_malloc(len ? len : 1);
    if (!e->dgram) { queue_entry_free(e); return -1; }
    if (len) memcpy(e->dgram, data, len);
    e->len = (uint16_t)len;
    queue_data_put(p->tx, e);
    return 0;
}

// ======================= test 1: handshake + all message sizes =======================

static int test1_sizes(void) {
    struct UASYNC *ua = uasync_create(); TASSERT(ua);
    struct test_peer srv = {0}, cli = {0};
    uint16_t port = BASE_PORT + 1;

    struct stcp_server *ss = stcp_server_create(ua, port, &s_keys, NULL, NULL, server_connect_cb, &srv, peer_close_cb, &srv, AF_INET); TASSERT(ss);
    struct stcp_client *sc = stcp_client_connect(ua, "127.0.0.1", port, &c_keys, s_keys.public_key, NULL, 0, 0, 0, 200, client_ready_cb, &cli, peer_close_cb, &cli, NULL); TASSERT(sc);

    size_t sizes[] = {0, 1, 16, 17, 255, 256, 1000, 65535};
    int n_sizes = 8;
    size_t total = 0; for (int i = 0; i < n_sizes; i++) total += sizes[i];
    uint8_t *payload = u_malloc(65536);
    for (int i = 0; i < 65536; i++) payload[i] = (uint8_t)(i * 7 + 13);

    int sent = 0, ticks = 0;
    while (srv.msg_count < n_sizes && ticks < 200) {
        uasync_poll(ua, 10);
        if (srv.ready && cli.ready && !sent) {
            for (int i = 0; i < n_sizes; i++) TASSERT(peer_send(&cli, payload, sizes[i]) == 0);
            sent = 1;
        }
        ticks++;
    }
    TASSERT(srv.msg_count == n_sizes);
    TASSERT(srv.accum_len == total);
    size_t off = 0;
    for (int i = 0; i < n_sizes; i++) {
        TASSERT(memcmp(srv.accum + off, payload, sizes[i]) == 0);
        off += sizes[i];
    }
    u_free(payload);
    peer_cleanup(&srv); peer_cleanup(&cli);
    if (srv.conn) stcp_conn_free(srv.conn);
    stcp_client_destroy(sc); stcp_server_destroy(ss);
    uasync_destroy(ua, 1);
    return 0;
}

// ======================= test 2: many sequential messages =======================

static int test2_many(void) {
    struct UASYNC *ua = uasync_create(); TASSERT(ua);
    struct test_peer srv = {0}, cli = {0};
    uint16_t port = BASE_PORT + 2;

    struct stcp_server *ss = stcp_server_create(ua, port, &s_keys, NULL, NULL, server_connect_cb, &srv, peer_close_cb, &srv, AF_INET); TASSERT(ss);
    struct stcp_client *sc = stcp_client_connect(ua, "127.0.0.1", port, &c_keys, s_keys.public_key, NULL, 0, 0, 0, 200, client_ready_cb, &cli, peer_close_cb, &cli, NULL); TASSERT(sc);

    int sent = 0, ticks = 0;
    while (srv.msg_count < 200 && ticks < 200) {
        uasync_poll(ua, 10);
        if (srv.ready && cli.ready && !sent) {
            for (int i = 0; i < 200; i++) {
                uint8_t buf[8];
                buf[0] = (uint8_t)(i >> 0); buf[1] = (uint8_t)(i >> 8);
                buf[2] = (uint8_t)(i >> 16); buf[3] = (uint8_t)(i >> 24);
                buf[4] = (uint8_t)(i * 3);
                TASSERT(peer_send(&cli, buf, 5) == 0);
            }
            sent = 1;
        }
        ticks++;
    }
    TASSERT(srv.msg_count == 200);
    TASSERT(srv.accum_len == 200 * 5);
    for (int i = 0; i < 200; i++) {
        uint32_t v; memcpy(&v, srv.accum + i * 5, 4); TASSERT(v == (uint32_t)i);
        TASSERT(srv.accum[i * 5 + 4] == (uint8_t)(i * 3));
    }
    peer_cleanup(&srv); peer_cleanup(&cli);
    if (srv.conn) stcp_conn_free(srv.conn);
    stcp_client_destroy(sc); stcp_server_destroy(ss);
    uasync_destroy(ua, 1);
    return 0;
}

// ======================= test 3: wrong peer pubkey =======================

static int test3_wrong_key(void) {
    struct UASYNC *ua = uasync_create(); TASSERT(ua);
    struct test_peer srv = {0}, cli = {0};
    uint16_t port = BASE_PORT + 3;

    struct stcp_server *ss = stcp_server_create(ua, port, &s_keys, NULL, NULL, server_connect_cb, &srv, peer_close_cb, &srv, AF_INET); TASSERT(ss);

    struct SC_MYKEYS rogue;
    TASSERT(sc_generate_keypair(&rogue) == SC_OK);
    struct stcp_client *sc = stcp_client_connect(ua, "127.0.0.1", port, &c_keys, rogue.public_key, NULL, 0, 0, 0, 200, client_ready_cb, &cli, peer_close_cb, &cli, NULL); TASSERT(sc);

    int ticks = 0;
    while (ticks < 200) {
        uasync_poll(ua, 10);
        if (cli.closed || srv.closed) break;
        ticks++;
    }
    TASSERT(!cli.ready);
    TASSERT(!srv.ready);

    peer_cleanup(&srv); peer_cleanup(&cli);
    stcp_client_destroy(sc); stcp_server_destroy(ss);
    uasync_destroy(ua, 1);
    return 0;
}

// ======================= test 4: close detection =======================

static int test4_close(void) {
    struct UASYNC *ua = uasync_create(); TASSERT(ua);
    struct test_peer srv = {0}, cli = {0};
    uint16_t port = BASE_PORT + 4;

    struct stcp_server *ss = stcp_server_create(ua, port, &s_keys, NULL, NULL, server_connect_cb, &srv, peer_close_cb, &srv, AF_INET); TASSERT(ss);
    struct stcp_client *sc = stcp_client_connect(ua, "127.0.0.1", port, &c_keys, s_keys.public_key, NULL, 0, 0, 0, 200, client_ready_cb, &cli, peer_close_cb, &cli, NULL); TASSERT(sc);

    int closed = 0, ticks = 0;
    while (!srv.closed && ticks < 200) {
        uasync_poll(ua, 10);
        if (srv.ready && cli.ready && !closed) {
            uint8_t m = 0xAB; peer_send(&cli, &m, 1);
            closed = 1;
        }
        if (closed && srv.msg_count >= 1 && cli.conn) {
            stcp_conn_free(cli.conn); cli.conn = NULL;
            cli.closed = 1;
        }
        ticks++;
    }
    TASSERT(srv.closed);

    peer_cleanup(&srv); peer_cleanup(&cli);
    stcp_client_destroy(sc); stcp_server_destroy(ss);
    uasync_destroy(ua, 1);
    return 0;
}

// ======================= test 5: multiple concurrent clients =======================

static struct test_peer *g_multi_peers;
static int g_multi_idx, g_multi_max;

static void multi_connect_cb(struct stcp_conn *conn, void *arg) {
    (void)arg;
    int i = g_multi_idx++;
    if (i >= g_multi_max) return;
    struct test_peer *p = &g_multi_peers[i];
    setup_peer(p, conn);
}

static int test5_multi(void) {
    struct UASYNC *ua = uasync_create(); TASSERT(ua);
    uint16_t port = BASE_PORT + 5;

    #define NCLI 3
    struct test_peer srvp[NCLI];
    struct test_peer clip[NCLI];
    memset(srvp, 0, sizeof(srvp)); memset(clip, 0, sizeof(clip));

    g_multi_peers = srvp; g_multi_idx = 0; g_multi_max = NCLI;
    struct stcp_server *ss = stcp_server_create(ua, port, &s_keys, NULL, NULL, multi_connect_cb, NULL, NULL, NULL, AF_INET); TASSERT(ss);

    struct stcp_client *clients[NCLI] = {0};
    for (int i = 0; i < NCLI; i++) {
        clients[i] = stcp_client_connect(ua, "127.0.0.1", port, &c_keys, s_keys.public_key, NULL, 0, 0, 0, 200, client_ready_cb, &clip[i], peer_close_cb, &clip[i], NULL);
        TASSERT(clients[i]);
    }

    int sent = 0, ticks = 0;
    while (ticks < 200) {
        uasync_poll(ua, 10);
        if (!sent) {
            int all_ready = 1;
            for (int i = 0; i < NCLI; i++) if (!clip[i].ready || !srvp[i].ready) all_ready = 0;
            if (all_ready) {
                for (int i = 0; i < NCLI; i++) {
                    uint8_t buf[4]; buf[0] = (uint8_t)i; buf[1] = (uint8_t)(i * 17 + 42);
                    TASSERT(peer_send(&clip[i], buf, 2) == 0);
                }
                sent = 1;
            }
        }
        if (sent) {
            int all_got = 1;
            for (int i = 0; i < NCLI; i++) if (srvp[i].msg_count < 1) all_got = 0;
            if (all_got) break;
        }
        ticks++;
    }
    for (int i = 0; i < NCLI; i++) {
        TASSERT(srvp[i].msg_count >= 1);
        TASSERT(srvp[i].accum_len == 2);
        TASSERT(srvp[i].accum[0] == (uint8_t)i);
        TASSERT(srvp[i].accum[1] == (uint8_t)(i * 17 + 42));
    }
    for (int i = 0; i < NCLI; i++) {
        peer_cleanup(&srvp[i]); peer_cleanup(&clip[i]);
        if (srvp[i].conn) stcp_conn_free(srvp[i].conn);
        stcp_client_destroy(clients[i]);
    }
    stcp_server_destroy(ss);
    uasync_destroy(ua, 1);
    return 0;
}

// ======================= test 6: interleaved send/recv =======================

static int test6_interleaved(void) {
    struct UASYNC *ua = uasync_create(); TASSERT(ua);
    struct test_peer srv = {0}, cli = {0};
    uint16_t port = BASE_PORT + 6;

    struct stcp_server *ss = stcp_server_create(ua, port, &s_keys, NULL, NULL, server_connect_cb, &srv, peer_close_cb, &srv, AF_INET); TASSERT(ss);
    struct stcp_client *sc = stcp_client_connect(ua, "127.0.0.1", port, &c_keys, s_keys.public_key, NULL, 0, 0, 0, 200, client_ready_cb, &cli, peer_close_cb, &cli, NULL); TASSERT(sc);

    int round = 0, ticks = 0;
    while (srv.msg_count < 50 || cli.msg_count < 50) {
        uasync_poll(ua, 10);
        if (srv.ready && cli.ready && round < 50) {
            uint8_t cb = (uint8_t)(round + 100);
            uint8_t sb = (uint8_t)(round + 200);
            if (peer_send(&cli, &cb, 1) == 0 && peer_send(&srv, &sb, 1) == 0) round++;
        }
        if (++ticks > 200) break;
    }
    TASSERT(srv.msg_count >= 50);
    TASSERT(cli.msg_count >= 50);
    for (int i = 0; i < 50; i++) {
        TASSERT(srv.accum[i] == (uint8_t)(i + 100));
        TASSERT(cli.accum[i] == (uint8_t)(i + 200));
    }

    peer_cleanup(&srv); peer_cleanup(&cli);
    if (srv.conn) stcp_conn_free(srv.conn);
    stcp_client_destroy(sc); stcp_server_destroy(ss);
    uasync_destroy(ua, 1);
    return 0;
}

// ======================= test 7: 4MB bulk transfer (pending queue stress) =======================

static int test7_bulk_4mb(void) {
    struct UASYNC *ua = uasync_create(); TASSERT(ua);
    struct test_peer srv = {0}, cli = {0};
    uint16_t port = BASE_PORT + 7;

    struct stcp_server *ss = stcp_server_create(ua, port, &s_keys, NULL, NULL, server_connect_cb, &srv, peer_close_cb, &srv, AF_INET); TASSERT(ss);
    struct stcp_client *sc = stcp_client_connect(ua, "127.0.0.1", port, &c_keys, s_keys.public_key, NULL, 0, 0, 0, 200, client_ready_cb, &cli, peer_close_cb, &cli, NULL); TASSERT(sc);

    #define N_BULK 64
    #define SZ_BULK 65535
    size_t total = N_BULK * SZ_BULK;  // 4,194,240 bytes
    uint8_t *payload = u_malloc(total); TASSERT(payload);
    for (size_t i = 0; i < total; i++) payload[i] = (uint8_t)(i * 7 + 13);

    int sent = 0, ticks = 0;
    while (srv.msg_count < N_BULK && ticks < 10000) {
        uasync_poll(ua, 10);
        if (srv.ready && cli.ready && !sent) {
            for (int i = 0; i < N_BULK; i++)
                TASSERT(peer_send(&cli, payload + i * SZ_BULK, SZ_BULK) == 0);
            sent = 1;
        }
        ticks++;
    }
    DEBUG_INFO(DEBUG_CATEGORY_GENERAL, "bulk: server received %d msgs, %zu bytes in %d ticks", srv.msg_count, srv.accum_len, ticks);
    TASSERT(srv.msg_count == N_BULK);
    TASSERT(srv.accum_len == total);
    TASSERT(memcmp(srv.accum, payload, total) == 0);

    u_free(payload);
    peer_cleanup(&srv); peer_cleanup(&cli);
    if (srv.conn) stcp_conn_free(srv.conn);
    stcp_client_destroy(sc); stcp_server_destroy(ss);
    uasync_destroy(ua, 1);
    return 0;
}

// ======================= test 8: server recv error → close chain (allocated=1 + on_close + deferred free) =======================

static int test8_srv_recv_close(void) {
    struct UASYNC *ua = uasync_create(); TASSERT(ua);
    struct test_peer srv = {0}, cli = {0};
    uint16_t port = BASE_PORT + 8;

    struct stcp_server *ss = stcp_server_create(ua, port, &s_keys, NULL, NULL, server_connect_cb, &srv, peer_close_cb, &srv, AF_INET); TASSERT(ss);
    struct stcp_client *sc = stcp_client_connect(ua, "127.0.0.1", port, &c_keys, s_keys.public_key, NULL, 0, 0, 0, 200, client_ready_cb, &cli, peer_close_cb, &cli, NULL); TASSERT(sc);

    int ticks = 0;
    while ((!srv.ready || !cli.ready) && ticks < 200) { uasync_poll(ua, 10); ticks++; }
    TASSERT(srv.ready && cli.ready);

    socket_close_wrapper(cli.conn->sock); cli.conn->sock = SOCKET_INVALID;

    ticks = 0;
    while (!srv.closed && ticks < 200) { uasync_poll(ua, 10); ticks++; }
    TASSERT(srv.closed);

    // server conn freed via deferred free (allocated=1 + on_close=peer_close_cb)
    srv.conn = NULL;   // prevent explicit stcp_conn_free double-free
    srv.ready = 0;

    peer_cleanup(&srv); peer_cleanup(&cli);
    stcp_client_destroy(sc); stcp_server_destroy(ss);
    uasync_destroy(ua, 1);  // flush deferred → stcp_conn_free(srv_conn)
    return 0;
}

// ======================= main =======================

int main(void) {
    debug_config_init();
    debug_set_level(DEBUG_LEVEL_INFO);
    debug_set_categories(DEBUG_CATEGORY_GENERAL | DEBUG_CATEGORY_SOCKET | DEBUG_CATEGORY_CRYPTO);

    DEBUG_INFO(DEBUG_CATEGORY_GENERAL, "============================================");
    DEBUG_INFO(DEBUG_CATEGORY_GENERAL, "=== STCP Integration Tests ===");

    TASSERT(sc_generate_keypair(&s_keys) == SC_OK);
    TASSERT(sc_generate_keypair(&c_keys) == SC_OK);

    TRUN(test1_sizes);
    TRUN(test2_many);
    TRUN(test3_wrong_key);
    TRUN(test4_close);
    TRUN(test5_multi);
    TRUN(test6_interleaved);
    TRUN(test7_bulk_4mb);
    TRUN(test8_srv_recv_close);

    DEBUG_INFO(DEBUG_CATEGORY_GENERAL, "============================================");
    DEBUG_INFO(DEBUG_CATEGORY_GENERAL, "Results: %d/%d passed", tests_passed, tests_total);
    return tests_passed == tests_total ? 0 : 1;
}