/**
 * @file wifi.c
 * @brief WiFi STA Management
 */

#include <string.h>
#include "wifi.h"
#include "esp_wifi.h"
#include "esp_event.h"
#include "esp_log.h"
#include "esp_netif.h"
#include "freertos/FreeRTOS.h"
#include "freertos/event_groups.h"
#include "freertos/task.h"

static const char *TAG = "nexus_wifi";

/* Event group bits */
#define WIFI_CONNECTED_BIT  BIT0
#define WIFI_FAIL_BIT       BIT1

/* Static state */
static EventGroupHandle_t s_wifi_event_group = NULL;
static esp_netif_t *s_sta_netif = NULL;
static esp_event_handler_instance_t s_any_id_instance = NULL;
static esp_event_handler_instance_t s_got_ip_instance = NULL;
static bool s_initialized = false;

/**
 * @brief WiFi event handler
 */
static void wifi_event_handler(void *arg, esp_event_base_t event_base,
                               int32_t event_id, void *event_data)
{
    if (event_base == WIFI_EVENT) {
        switch (event_id) {
            case WIFI_EVENT_STA_START:
                ESP_LOGI(TAG, "WiFi STA started, connecting...");
                esp_wifi_connect();
                break;

            case WIFI_EVENT_STA_DISCONNECTED:
                ESP_LOGW(TAG, "WiFi disconnected");
                xEventGroupClearBits(s_wifi_event_group, WIFI_CONNECTED_BIT);
                /* Auto-reconnect is handled by esp_wifi_connect() below */
                esp_wifi_connect();
                break;

            default:
                break;
        }
    } else if (event_base == IP_EVENT && event_id == IP_EVENT_STA_GOT_IP) {
        ip_event_got_ip_t *event = (ip_event_got_ip_t *)event_data;
        ESP_LOGI(TAG, "Got IP: " IPSTR, IP2STR(&event->ip_info.ip));
        xEventGroupSetBits(s_wifi_event_group, WIFI_CONNECTED_BIT);
    }
}

esp_err_t wifi_init_sta(const char *ssid, const char *password)
{
    if (ssid == NULL || password == NULL) {
        return ESP_ERR_INVALID_ARG;
    }

    if (s_initialized) {
        ESP_LOGW(TAG, "WiFi already initialized");
        return ESP_OK;
    }

    ESP_LOGI(TAG, "Initializing WiFi STA...");

    /* Create event group */
    s_wifi_event_group = xEventGroupCreate();

    /* Initialize network interface */
    ESP_ERROR_CHECK(esp_netif_init());
    ESP_ERROR_CHECK(esp_event_loop_create_default());
    s_sta_netif = esp_netif_create_default_wifi_sta();

    /* Initialize WiFi */
    wifi_init_config_t cfg = WIFI_INIT_CONFIG_DEFAULT();
    ESP_ERROR_CHECK(esp_wifi_init(&cfg));

    /* Register event handlers */
    ESP_ERROR_CHECK(esp_event_handler_instance_register(
        WIFI_EVENT, ESP_EVENT_ANY_ID,
        &wifi_event_handler, NULL, &s_any_id_instance));
    ESP_ERROR_CHECK(esp_event_handler_instance_register(
        IP_EVENT, IP_EVENT_STA_GOT_IP,
        &wifi_event_handler, NULL, &s_got_ip_instance));

    /* Configure WiFi */
    wifi_config_t wifi_config = {
        .sta = {
            .threshold.authmode = WIFI_AUTH_WPA2_PSK,
            .pmf_cfg = {
                .capable = true,
                .required = false,
            },
        },
    };

    strncpy((char *)wifi_config.sta.ssid, ssid, sizeof(wifi_config.sta.ssid) - 1);
    strncpy((char *)wifi_config.sta.password, password, sizeof(wifi_config.sta.password) - 1);

    ESP_ERROR_CHECK(esp_wifi_set_mode(WIFI_MODE_STA));
    ESP_ERROR_CHECK(esp_wifi_set_config(WIFI_IF_STA, &wifi_config));
    ESP_ERROR_CHECK(esp_wifi_start());

    s_initialized = true;
    ESP_LOGI(TAG, "WiFi STA initialized, will connect to: %s", ssid);

    return ESP_OK;
}

esp_err_t wifi_connect(void)
{
    if (!s_initialized) {
        ESP_LOGE(TAG, "WiFi not initialized, call wifi_init_sta first");
        return ESP_ERR_INVALID_STATE;
    }

    ESP_LOGI(TAG, "Connecting to WiFi...");
    esp_err_t err = esp_wifi_connect();
    if (err != ESP_OK) {
        ESP_LOGE(TAG, "WiFi connect failed: %s", esp_err_to_name(err));
    }
    return err;
}

esp_err_t wifi_disconnect(void)
{
    if (!s_initialized) {
        return ESP_ERR_INVALID_STATE;
    }

    ESP_LOGI(TAG, "Disconnecting from WiFi...");
    return esp_wifi_disconnect();
}

bool wifi_is_connected(void)
{
    if (s_wifi_event_group == NULL) {
        return false;
    }
    return (xEventGroupGetBits(s_wifi_event_group) & WIFI_CONNECTED_BIT) != 0;
}