/**
 * @file wifi.c
 * @brief Implementation of WiFi station mode module.
 */

#include "wifi.h"

#include "esp_timer.h"
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "freertos/event_groups.h"
#include "esp_wifi.h"
#include "esp_event.h"
#include "esp_log.h"
#include "esp_netif.h"
#include <lwip/sockets.h>

#include <string.h>

/** @brief Event bit for successful connection. */
#define WIFI_CONNECTED_BIT BIT0

/** @brief Event bit for connection failure. */
#define WIFI_FAIL_BIT BIT1

/** @brief Maximum connection retry attempts. */
#define MAX_RETRY_COUNT 10

/** @brief Delay between retries in milliseconds. */
#define RETRY_DELAY_MS 1000

static const char *TAG = "wifi";

static EventGroupHandle_t s_wifi_event_group;
static int s_retry_num = 0;
static bool s_initial_connect = true;

static void event_handler(void *arg, esp_event_base_t event_base,
                          int32_t event_id, void *event_data);

esp_err_t initWifi(void)
{
    s_wifi_event_group = xEventGroupCreate();
    if (s_wifi_event_group == NULL)
    {
        ESP_LOGE(TAG, "Failed to create event group");
        return ESP_FAIL;
    }

    ESP_ERROR_CHECK(esp_netif_init());
    ESP_ERROR_CHECK(esp_event_loop_create_default());

    esp_netif_t *my_sta = esp_netif_create_default_wifi_sta();
    ESP_ERROR_CHECK(esp_netif_dhcpc_stop(my_sta));
    esp_netif_ip_info_t ip_info;
    ip_info.ip.addr = ipaddr_addr(CONFIG_STATIC_IP_ADDR);
    ip_info.gw.addr = ipaddr_addr(CONFIG_STATIC_GATEWAY_IP_ADDR);
    ip_info.netmask.addr = ipaddr_addr(CONFIG_STATIC_IP_NETMASK);
    ESP_ERROR_CHECK(esp_netif_set_ip_info(my_sta, &ip_info));

    wifi_init_config_t cfg = WIFI_INIT_CONFIG_DEFAULT();
    ESP_ERROR_CHECK(esp_wifi_init(&cfg));
    esp_event_handler_instance_t instance_any_id;
    esp_event_handler_instance_t instance_got_ip;
    ESP_ERROR_CHECK(esp_event_handler_instance_register(WIFI_EVENT,
                                                        ESP_EVENT_ANY_ID,
                                                        &event_handler,
                                                        NULL,
                                                        &instance_any_id));
    ESP_ERROR_CHECK(esp_event_handler_instance_register(IP_EVENT,
                                                        IP_EVENT_STA_GOT_IP,
                                                        &event_handler,
                                                        NULL,
                                                        &instance_got_ip));

    wifi_config_t wifi_config = {
        .sta = {
            .ssid = CONFIG_SSID,
            .password = CONFIG_WIFI_PASSWORD,
            .threshold.authmode = WIFI_AUTH_WPA2_PSK,
        },
    };
    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());

    ESP_ERROR_CHECK(esp_wifi_set_max_tx_power(78));
    ESP_ERROR_CHECK(esp_wifi_set_ps(WIFI_PS_MIN_MODEM));

    ESP_LOGI(TAG, "WiFi init finished, waiting for connection...");

    EventBits_t bits = xEventGroupWaitBits(s_wifi_event_group,
                                           WIFI_CONNECTED_BIT | WIFI_FAIL_BIT,
                                           pdFALSE,
                                           pdFALSE,
                                           portMAX_DELAY);

    if (bits & WIFI_CONNECTED_BIT)
    {
        ESP_LOGI(TAG, "Connected to AP SSID:%s", CONFIG_SSID);
    }
    else if (bits & WIFI_FAIL_BIT)
    {
        ESP_LOGE(TAG, "Failed to connect to SSID:%s", CONFIG_SSID);
        return ESP_FAIL;
    }
    else
    {
        ESP_LOGE(TAG, "Unexpected event");
        return ESP_FAIL;
    }

    s_initial_connect = false;

    ESP_LOGI(TAG, "Initialized successfully");
    return ESP_OK;
}

/**
 * @brief WiFi event handler.
 * @param arg User argument (unused).
 * @param event_base Event base.
 * @param event_id Event ID.
 * @param event_data Event data.
 */
static void event_handler(void *arg, esp_event_base_t event_base,
                          int32_t event_id, void *event_data)
{
    if (event_base == WIFI_EVENT && event_id == WIFI_EVENT_STA_START)
    {
        esp_wifi_connect();
    }
    else if (event_base == WIFI_EVENT && event_id == WIFI_EVENT_STA_DISCONNECTED)
    {
        wifi_event_sta_disconnected_t *event = (wifi_event_sta_disconnected_t *)event_data;
        ESP_LOGW(TAG, "Disconnected from AP (reason: %d)", event->reason);

        if (s_initial_connect)
        {
            // During initial connection phase, use retry limit
            if (s_retry_num < MAX_RETRY_COUNT)
            {
                vTaskDelay(pdMS_TO_TICKS(RETRY_DELAY_MS));
                esp_wifi_connect();
                s_retry_num++;
                ESP_LOGI(TAG, "Retry to connect to the AP (%d/%d)", s_retry_num, MAX_RETRY_COUNT);
            }
            else
            {
                xEventGroupSetBits(s_wifi_event_group, WIFI_FAIL_BIT);
                ESP_LOGE(TAG, "Failed to connect after %d attempts", MAX_RETRY_COUNT);
            }
        }
        else
        {
            // After initial connection, always try to reconnect with delay
            vTaskDelay(pdMS_TO_TICKS(RETRY_DELAY_MS));
            esp_wifi_connect();
            ESP_LOGI(TAG, "Attempting to reconnect to the AP...");
        }
    }
    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));
        s_retry_num = 0;

        if (s_initial_connect)
        {
            xEventGroupSetBits(s_wifi_event_group, WIFI_CONNECTED_BIT);
        }
        else
        {
            ESP_LOGI(TAG, "Successfully reconnected to AP");
        }
    }
}