/*
 * MTG RFID Companion - Wi-Fi manager (Core 0)
 */

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

static const char *TAG = "wifi";

#define WIFI_RETRY_MAX   (UINT8_MAX)
#define WIFI_RECONNECT_DELAY_MS (3000)

static EventGroupHandle_t s_wifi_group = NULL;
#define WIFI_CONNECTED_BIT BIT0

static int s_retry_count = 0;

static void wifi_event_handler(void *arg, esp_event_base_t base, int32_t id, void *data)
{
    (void)arg;

    if (base == WIFI_EVENT && id == WIFI_EVENT_STA_START) {
        ESP_LOGI(TAG, "station started, connecting...");
        esp_wifi_connect();
    } else if (base == WIFI_EVENT && id == WIFI_EVENT_STA_DISCONNECTED) {
        if (s_retry_count < WIFI_RETRY_MAX) {
            ESP_LOGW(TAG, "disconnected (%d), retrying in %d ms", s_retry_count, WIFI_RECONNECT_DELAY_MS);
            xEventGroupClearBits(s_wifi_group, WIFI_CONNECTED_BIT);
            vTaskDelay(pdMS_TO_TICKS(WIFI_RECONNECT_DELAY_MS));
            esp_wifi_connect();
            s_retry_count++;
        }
    } else if (base == IP_EVENT && id == IP_EVENT_STA_GOT_IP) {
        ip_event_got_ip_t *event = (ip_event_got_ip_t *)data;
        ESP_LOGI(TAG, "connected, IP: " IPSTR, IP2STR(&event->ip_info.ip));
        s_retry_count = 0;
        xEventGroupSetBits(s_wifi_group, WIFI_CONNECTED_BIT);
    }
}

esp_err_t wifi_manager_init(void)
{
    esp_err_t ret = nvs_flash_init();
    if (ret == ESP_ERR_NVS_NO_FREE_PAGES || ret == ESP_ERR_NVS_NEW_VERSION_FOUND) {
        ESP_ERROR_CHECK(nvs_flash_erase());
        ret = nvs_flash_init();
    }
    if (ret != ESP_OK) {
        return ret;
    }

    s_wifi_group = xEventGroupCreate();
    if (s_wifi_group == NULL) {
        return ESP_ERR_NO_MEM;
    }

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

    wifi_init_config_t cfg = WIFI_INIT_CONFIG_DEFAULT();
    ESP_ERROR_CHECK(esp_wifi_init(&cfg));

    ESP_ERROR_CHECK(esp_event_handler_instance_register(
        WIFI_EVENT, ESP_EVENT_ANY_ID, &wifi_event_handler, NULL, NULL));
    ESP_ERROR_CHECK(esp_event_handler_instance_register(
        IP_EVENT, IP_EVENT_STA_GOT_IP, &wifi_event_handler, NULL, NULL));

    return ESP_OK;
}

bool wifi_manager_sta_configured(void)
{
#ifndef CONFIG_MTG_WIFI_SSID
    return false;
#else
    const char *ssid = CONFIG_MTG_WIFI_SSID;
    return strlen(ssid) > 0 && strstr(ssid, "YOUR_") == NULL;
#endif
}

esp_err_t wifi_manager_start(void)
{
#ifndef CONFIG_MTG_WIFI_SSID
#error "Missing CONFIG_MTG_WIFI_SSID - run idf.py menuconfig"
#endif

    /* Empty SSID, or an untouched sdkconfig.defaults.esp32 placeholder:
     * keep station mode disabled so we don't hammer a bogus AP at boot. */
    if (!wifi_manager_sta_configured()) {
        ESP_LOGW(TAG, "no SSID configured - Wi-Fi station skipped (set CONFIG_MTG_WIFI_SSID)");
        return ESP_OK;
    }

    const char *ssid = CONFIG_MTG_WIFI_SSID;
    const char *pass = CONFIG_MTG_WIFI_PASS;

    wifi_config_t wifi_config = {
        .sta = {
            .threshold.authmode = WIFI_AUTH_WPA2_PSK,
        },
    };
    strncpy((char *)wifi_config.sta.ssid, ssid, sizeof(wifi_config.sta.ssid) - 1);
    strncpy((char *)wifi_config.sta.password, pass, 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());

    ESP_LOGI(TAG, "station mode started for '%s'", ssid);
    return ESP_OK;
}

bool wifi_manager_connected(void)
{
    return s_wifi_group != NULL && (xEventGroupGetBits(s_wifi_group) & WIFI_CONNECTED_BIT) != 0;
}

esp_err_t wifi_manager_wait_connected(TickType_t timeout_ticks)
{
    if (s_wifi_group == NULL) {
        return ESP_ERR_INVALID_STATE;
    }
    EventBits_t bits = xEventGroupWaitBits(s_wifi_group, WIFI_CONNECTED_BIT, pdFALSE, pdTRUE, timeout_ticks);
    return (bits & WIFI_CONNECTED_BIT) ? ESP_OK : ESP_ERR_TIMEOUT;
}