/**
 * @file tunnel.c
 * @brief WireGuard Tunnel Management (Stub)
 *
 * TODO: Integrate wireguard-esp32 component for actual WireGuard tunnel.
 * These are stubs that log and maintain state for the heartbeat loop.
 */

#include <string.h>
#include <time.h>
#include "tunnel.h"
#include "config.h"
#include "esp_log.h"

static const char *TAG = "nexus_tunnel";

/* Tunnel state */
static bool s_tunnel_up = false;
static int64_t s_last_handshake = 0;

esp_err_t tunnel_init(const wg_config_t *config)
{
    if (config == NULL) {
        return ESP_ERR_INVALID_ARG;
    }

    ESP_LOGI(TAG, "Initializing WireGuard tunnel...");
    ESP_LOGI(TAG, "  Device: %s", config->device_id);
    ESP_LOGI(TAG, "  Endpoint: %s", config->endpoint);
    ESP_LOGI(TAG, "  Internal IP: %s", config->internal_ip);
    ESP_LOGI(TAG, "  Allowed IPs: %s", config->allowed_ips);

    /* TODO: integrate wireguard-esp32 component */
    /* Steps when integrated:
     * 1. Parse private_key hex to binary
     * 2. Parse server_pub hex to binary
     * 3. Parse preshared_key hex to binary
     * 4. Create WireGuard device with private_key
     * 5. Add peer with server_pub, preshared_key, endpoint
     * 6. Set peer allowed_ips
     * 7. Start WireGuard tunnel
     */

    /* Stub: mark tunnel as up and record handshake time */
    s_tunnel_up = true;
    s_last_handshake = (int64_t)time(NULL);

    ESP_LOGI(TAG, "WireGuard tunnel initialized (stub)");
    return ESP_OK;
}

esp_err_t tunnel_apply_config(const wg_config_t *config)
{
    if (config == NULL) {
        return ESP_ERR_INVALID_ARG;
    }

    ESP_LOGI(TAG, "Applying WireGuard config...");
    ESP_LOGI(TAG, "  Endpoint: %s", config->endpoint);

    /* TODO: integrate wireguard-esp32 component */
    /* Steps when integrated:
     * 1. Stop existing tunnel
     * 2. Reconfigure device with new keys
     * 3. Reconfigure peer with new endpoint/allowed_ips
     * 4. Restart tunnel
     */

    s_tunnel_up = true;
    s_last_handshake = (int64_t)time(NULL);

    ESP_LOGI(TAG, "WireGuard config applied (stub)");
    return ESP_OK;
}

esp_err_t tunnel_rebuild(const wg_config_t *config)
{
    if (config == NULL) {
        return ESP_ERR_INVALID_ARG;
    }

    ESP_LOGI(TAG, "Rebuilding WireGuard tunnel...");

    /* Mark tunnel down during rebuild */
    s_tunnel_up = false;

    /* Apply new config */
    esp_err_t err = tunnel_apply_config(config);
    if (err != ESP_OK) {
        ESP_LOGE(TAG, "Tunnel rebuild failed: %s", esp_err_to_name(err));
        return err;
    }

    ESP_LOGI(TAG, "WireGuard tunnel rebuilt successfully");
    return ESP_OK;
}

int64_t tunnel_get_last_handshake(void)
{
    return s_last_handshake;
}

bool tunnel_is_up(void)
{
    return s_tunnel_up;
}