#include <stdlib.h>
#include <string.h>
#include <stdint.h>

#include "../lib/ll_queue.h"
#include "../lib/debug_config.h"
#include "../lib/mem.h"
#include "utun_instance.h"
#include "etcp.h"
#include "config_parser.h"
#include "route_node.h"
#include "route_bgp.h"
#include "etcp_debug.h"



/**
 * @brief Получает указатель на массив IPv4-подсетей узла (без malloc/копирования).
 * 
 * Функция вычисляет смещение внутри динамической части BGP_NODEINFO_Q
 * и возвращает прямой указатель на массив struct BGP_NODEINFO_IPV4_SUBNET.
 * 
 * @param node         Указатель на BGP_NODEINFO_Q
 * @param out_subnets  [out] сюда будет записан указатель на первый элемент массива
 *                     (NULL если подсетей нет)
 * @return количество подсетей (>= 0) или -1 при ошибке
 */
int get_node_v4_sockets(struct NODEINFO_Q *node, const struct NODEINFO_IPV4_SOCKET **out_sockets) {
    if (!node || !out_sockets) {
        return -1;
    }
    *out_sockets = NULL;
    const struct NODEINFO *info = &node->node;
    if (info->local_v4_sockets == 0) {
        return 0;
    }
    const uint8_t *dynamic = (const uint8_t *)&node->node + sizeof(struct NODEINFO);
    dynamic += info->node_name_len;
    *out_sockets = (const struct NODEINFO_IPV4_SOCKET *)dynamic;
    DEBUG_TRACE(DEBUG_CATEGORY_ROUTING, "get_node_v4_sockets: returned %u IPv4 sockets from node %p",
                (unsigned)info->local_v4_sockets, (void*)node);
    return (int)info->local_v4_sockets;
}

int get_node_v6_sockets(struct NODEINFO_Q *node, const struct NODEINFO_IPV6_SOCKET **out_sockets) {
    if (!node || !out_sockets) {
        return -1;
    }
    *out_sockets = NULL;
    const struct NODEINFO *info = &node->node;
    if (info->local_v6_sockets == 0) {
        return 0;
    }
    const uint8_t *dynamic = (const uint8_t *)&node->node + sizeof(struct NODEINFO);
    dynamic += info->node_name_len;
    dynamic += info->local_v4_sockets * sizeof(struct NODEINFO_IPV4_SOCKET);
    *out_sockets = (const struct NODEINFO_IPV6_SOCKET *)dynamic;
    DEBUG_TRACE(DEBUG_CATEGORY_ROUTING, "get_node_v6_sockets: returned %u IPv6 sockets from node %p",
                (unsigned)info->local_v6_sockets, (void*)node);
    return (int)info->local_v6_sockets;
}

int get_node_routes(struct NODEINFO_Q *node, const struct NODEINFO_IPV4_SUBNET **out_subnets) {
    if (!node || !out_subnets) {
        return -1;
    }

    *out_subnets = NULL;

    const struct NODEINFO *info = &node->node;

    if (info->local_v4_subnets == 0) {
        return 0;   // успех, но нет подсетей
    }

    // Начало динамических полей сразу после фиксированной части NODEINFO
    const uint8_t *dynamic = (const uint8_t *)&node->node + sizeof(struct NODEINFO);

    // 1. Пропускаем node_name
    dynamic += info->node_name_len;

    // 2. Пропускаем local_v4_sockets
    dynamic += info->local_v4_sockets * sizeof(struct NODEINFO_IPV4_SOCKET);

    // 3. Пропускаем local_v6_sockets
    dynamic += info->local_v6_sockets * sizeof(struct NODEINFO_IPV6_SOCKET);

    // Теперь dynamic указывает точно на начало массива NODEINFO_IPV4_SUBNET
    *out_subnets = (const struct NODEINFO_IPV4_SUBNET *)dynamic;

    DEBUG_TRACE(DEBUG_CATEGORY_ROUTING, "get_node_routes: returned %u IPv4 subnets from node %p",
                (unsigned)info->local_v4_subnets, (void*)node);
    return (int)info->local_v4_subnets;
}

int route_bgp_update_my_nodeinfo(struct UTUN_INSTANCE* instance, struct ROUTE_BGP* bgp) {
    if (!instance || !bgp) {
        DEBUG_ERROR(DEBUG_CATEGORY_BGP, "route_bgp_update_my_nodeinfo: invalid args");
        return -1;
    }
    size_t name_len = 0;
    if (instance->name[0]) {
        name_len = strlen(instance->name);
        if (name_len > 63) name_len = 63;
    }
    int vc = 0;
    struct CFG_ROUTE_ENTRY* s = instance->config->my_subnets;
    while (s) {
        if (s->ip.family == AF_INET) vc++;
        s = s->next;
    }

    int sock_count = 0;
    struct ETCP_SOCKET* e_sock = instance->etcp_sockets;
    while (e_sock) {
        if (e_sock->local_addr.ss_family == AF_INET) sock_count++;
        e_sock = e_sock->next;
    }

    size_t dyn = name_len + sock_count * sizeof(struct NODEINFO_IPV4_SOCKET) + vc * sizeof(struct NODEINFO_IPV4_SUBNET);

    if (!bgp->local_node) {
        bgp->local_node = u_calloc(1, sizeof(struct NODEINFO_Q) + dyn);
        if (!bgp->local_node) return -1;
        bgp->local_node->node.node_id = instance->node_id;
        bgp->local_node->node.hop_count = 0;
        bgp->local_node->node.ver = 1;
        bgp->local_node->dirty = 1;
        bgp->local_node->last_ver = 1;
        bgp->local_node->node.local_v4_sockets = sock_count;
        bgp->local_node->node.local_v4_subnets = vc;
        bgp->local_node->node.node_name_len = name_len;
        memcpy(bgp->local_node->node.public_key, instance->my_keys.public_key, SC_PUBKEY_SIZE);
    }

    int changed = (vc != (int)bgp->local_node->node.local_v4_subnets)
               || (sock_count != (int)bgp->local_node->node.local_v4_sockets)
               || (name_len != bgp->local_node->node.node_name_len)
               || (memcmp(bgp->local_node->node.public_key, instance->my_keys.public_key, SC_PUBKEY_SIZE) != 0);

    if (!changed && vc > 0) {
        uint8_t* current = (uint8_t*)&bgp->local_node->node + sizeof(struct NODEINFO);
        current += name_len + sock_count * sizeof(struct NODEINFO_IPV4_SOCKET);
        struct NODEINFO_IPV4_SUBNET* ra = (struct NODEINFO_IPV4_SUBNET*)current;
        s = instance->config->my_subnets;
        bool same = true;
        while (s) {
            if (s->ip.family == AF_INET) {
                if (memcmp(ra->addr, &s->ip.addr.v4, 4) != 0 || ra->prefix_length != s->netmask) {
                    same = false;
                    break;
                }
                ra++;
            }
            s = s->next;
        }
        changed = !same;
    }

    if (!changed && sock_count > 0) {
        uint8_t* current = (uint8_t*)&bgp->local_node->node + sizeof(struct NODEINFO);
        current += name_len;
        struct NODEINFO_IPV4_SOCKET* sa = (struct NODEINFO_IPV4_SOCKET*)current;
        e_sock = instance->etcp_sockets;
        bool same = true;
        while (e_sock) {
            if (e_sock->local_addr.ss_family == AF_INET) {
                struct sockaddr_in* if_sin = (struct sockaddr_in*)&e_sock->interface_addr;
                struct sockaddr_in* nat_sin = (struct sockaddr_in*)&e_sock->nat_addr;
                uint8_t nat_addr_cmp[4] = {0};
                uint16_t nat_port_cmp = 0;
                if (e_sock->nat_addr.ss_family == AF_INET) {
                    memcpy(nat_addr_cmp, &nat_sin->sin_addr.s_addr, 4);
                    nat_port_cmp = ntohs(nat_sin->sin_port);
                }
                if (memcmp(sa->addr, &if_sin->sin_addr.s_addr, 4) != 0 || sa->port != ntohs(if_sin->sin_port) ||
                    memcmp(sa->nat_addr, nat_addr_cmp, 4) != 0 || sa->nat_port != nat_port_cmp ||
                    sa->type != e_sock->nat_type || sa->id != e_sock->sock_id) {
                    same = false;
                    break;
                }
                sa++;
            }
            e_sock = e_sock->next;
        }
        changed = !same;
    }

    if (changed) {
        if (bgp->local_node) u_free(bgp->local_node);
        bgp->local_node = u_calloc(1, sizeof(struct NODEINFO_Q) + dyn);
        if (!bgp->local_node) return -1;
        bgp->local_node->node.node_id = instance->node_id;
        bgp->local_node->node.hop_count = 0;
        uint8_t oldv = bgp->local_node->node.ver;
        bgp->local_node->node.ver = ((oldv + 1) % 255) + 1;
        bgp->local_node->node.local_v4_sockets = sock_count;
        bgp->local_node->node.local_v4_subnets = vc;
        bgp->local_node->node.node_name_len = name_len;
        memcpy(bgp->local_node->node.public_key, instance->my_keys.public_key, SC_PUBKEY_SIZE);
        bgp->local_node->dirty = 1;
        bgp->local_node->last_ver = bgp->local_node->node.ver;
        uint8_t* dp = (uint8_t*)&bgp->local_node->node + sizeof(struct NODEINFO);
        if (name_len) {
            memcpy(dp, instance->name, name_len);
            dp += name_len;
        }
        struct NODEINFO_IPV4_SOCKET* sa = (struct NODEINFO_IPV4_SOCKET*)dp;
        e_sock = instance->etcp_sockets;
        while (e_sock) {
            if (e_sock->local_addr.ss_family == AF_INET) {
                struct sockaddr_in* if_sin = (struct sockaddr_in*)&e_sock->interface_addr;
                struct sockaddr_in* nat_sin = (struct sockaddr_in*)&e_sock->nat_addr;
                memcpy(sa->addr, &if_sin->sin_addr.s_addr, 4);
                sa->port = ntohs(if_sin->sin_port);
                sa->type = e_sock->nat_type;
                sa->id = e_sock->sock_id;
                if (e_sock->nat_addr.ss_family == AF_INET) {
                    memcpy(sa->nat_addr, &nat_sin->sin_addr.s_addr, 4);
                    sa->nat_port = ntohs(nat_sin->sin_port);
                } else {
                    memset(sa->nat_addr, 0, 4);
                    sa->nat_port = 0;
                }
                DEBUG_INFO(DEBUG_CATEGORY_BGP, "NODEINFO socket: addr=0x%02x%02x%02x%02x port=%u nat=0x%02x%02x%02x%02x:%u",
                           sa->addr[0], sa->addr[1], sa->addr[2], sa->addr[3], sa->port,
                           sa->nat_addr[0], sa->nat_addr[1], sa->nat_addr[2], sa->nat_addr[3], sa->nat_port);
                sa++;
            }
            e_sock = e_sock->next;
        }
        dp = (uint8_t*)sa;
        struct NODEINFO_IPV4_SUBNET* ra = (struct NODEINFO_IPV4_SUBNET*)dp;
        s = instance->config->my_subnets;
        while (s) {
            if (s->ip.family == AF_INET) {
                memcpy(ra->addr, &s->ip.addr.v4, 4);
                ra->prefix_length = s->netmask;
                ra++;
            }
            s = s->next;
        }
    } else {
        bgp->local_node->last_ver = bgp->local_node->node.ver;
    }
    return vc;
}