/**
 * WiFi Manager - Verwaltet WiFi AP und Station Mode
 *
 * - Hotspot-Modus wenn keine WLAN-Daten konfiguriert
 * - Station-Modus wenn WLAN konfiguriert
 * - Automatischer Fallback zu Hotspot bei Verbindungsproblemen
 */

#include <string.h>
#include "wifi_manager.h"
#include "config/config_manager.h"
#include "esp_log.h"
#include "esp_wifi.h"
#include "esp_mac.h"
#include "esp_event.h"
#include "esp_netif.h"
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "freertos/event_groups.h"
#include "lwip/err.h"
#include "lwip/sys.h"

static const char* TAG = "WIFI_MGR";

// Event Bits
#define WIFI_CONNECTED_BIT  BIT0
#define WIFI_FAIL_BIT       BIT1

// Maximale Wiederholungsversuche
#define MAX_RETRY_COUNT     5

// State
static wifi_state_t s_state = WIFI_STATE_IDLE;
static EventGroupHandle_t s_wifi_event_group;
static esp_netif_t* s_netif_ap = NULL;
static esp_netif_t* s_netif_sta = NULL;
static int s_retry_count = 0;
static wifi_event_callback_t s_callback = NULL;
static bool s_initialized = false;

// Forward Declarations
static void wifi_event_handler(void* arg, esp_event_base_t event_base,
                               int32_t event_id, void* event_data);
static void ip_event_handler(void* arg, esp_event_base_t event_base,
                             int32_t event_id, void* event_data);

static void notify_callback(wifi_state_t state, void* data)
{
    s_state = state;
    if (s_callback) {
        s_callback(state, data);
    }
}

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_AP_START:
                ESP_LOGI(TAG, "AP gestartet");
                notify_callback(WIFI_STATE_AP_STARTED, NULL);
                break;

            case WIFI_EVENT_AP_STOP:
                ESP_LOGI(TAG, "AP gestoppt");
                break;

            case WIFI_EVENT_AP_STACONNECTED: {
                wifi_event_ap_staconnected_t* event = (wifi_event_ap_staconnected_t*)event_data;
                ESP_LOGI(TAG, "Client verbunden: %02x:%02x:%02x:%02x:%02x:%02x",
                         event->mac[0], event->mac[1], event->mac[2],
                         event->mac[3], event->mac[4], event->mac[5]);
                break;
            }

            case WIFI_EVENT_AP_STADISCONNECTED: {
                wifi_event_ap_stadisconnected_t* event = (wifi_event_ap_stadisconnected_t*)event_data;
                ESP_LOGI(TAG, "Client getrennt: %02x:%02x:%02x:%02x:%02x:%02x",
                         event->mac[0], event->mac[1], event->mac[2],
                         event->mac[3], event->mac[4], event->mac[5]);
                break;
            }

            case WIFI_EVENT_STA_START:
                ESP_LOGI(TAG, "STA gestartet, verbinde...");
                esp_wifi_connect();
                notify_callback(WIFI_STATE_STA_CONNECTING, NULL);
                break;

            case WIFI_EVENT_STA_DISCONNECTED: {
                wifi_event_sta_disconnected_t* event = (wifi_event_sta_disconnected_t*)event_data;
                ESP_LOGW(TAG, "Verbindung getrennt (Grund: %d)", event->reason);

                if (s_retry_count < MAX_RETRY_COUNT) {
                    s_retry_count++;
                    ESP_LOGI(TAG, "Wiederverbinden... (Versuch %d/%d)", s_retry_count, MAX_RETRY_COUNT);
                    vTaskDelay(pdMS_TO_TICKS(2000));
                    esp_wifi_connect();
                    notify_callback(WIFI_STATE_STA_DISCONNECTED, NULL);
                } else {
                    ESP_LOGE(TAG, "Max. Versuche erreicht - Fallback zu AP");
                    xEventGroupSetBits(s_wifi_event_group, WIFI_FAIL_BIT);
                    notify_callback(WIFI_STATE_STA_FAILED, NULL);
                    // Starte AP
                    wifi_manager_start_ap();
                }
                break;
            }

            case WIFI_EVENT_STA_CONNECTED:
                ESP_LOGI(TAG, "Mit AP verbunden");
                s_retry_count = 0;
                break;

            default:
                break;
        }
    }
}

static void ip_event_handler(void* arg, esp_event_base_t event_base,
                             int32_t event_id, void* event_data)
{
    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, "IP erhalten: " IPSTR, IP2STR(&event->ip_info.ip));
        s_retry_count = 0;
        xEventGroupSetBits(s_wifi_event_group, WIFI_CONNECTED_BIT);
        notify_callback(WIFI_STATE_STA_CONNECTED, NULL);
    }
}

esp_err_t wifi_manager_init(void)
{
    if (s_initialized) {
        return ESP_OK;
    }

    ESP_LOGI(TAG, "Initialisiere WiFi Manager");

    s_wifi_event_group = xEventGroupCreate();

    // TCP/IP Stack initialisieren
    ESP_ERROR_CHECK(esp_netif_init());

    // Netif für AP und STA erstellen
    s_netif_ap = esp_netif_create_default_wifi_ap();
    s_netif_sta = esp_netif_create_default_wifi_sta();

    // WiFi mit Standardkonfiguration initialisieren
    wifi_init_config_t cfg = WIFI_INIT_CONFIG_DEFAULT();
    ESP_ERROR_CHECK(esp_wifi_init(&cfg));

    // Event Handler registrieren
    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,
                                                        &ip_event_handler, NULL, NULL));

    // WiFi Storage
    ESP_ERROR_CHECK(esp_wifi_set_storage(WIFI_STORAGE_RAM));

    s_initialized = true;
    return ESP_OK;
}

esp_err_t wifi_manager_start(void)
{
    ESP_LOGI(TAG, "Starte WiFi...");

    const device_config_t* config = config_get();

    if (config->wifi.configured) {
        // Station Mode - mit konfiguriertem WLAN verbinden
        return wifi_manager_connect(&config->wifi);
    } else {
        // AP Mode - Hotspot starten
        return wifi_manager_start_ap();
    }
}

esp_err_t wifi_manager_stop(void)
{
    ESP_LOGI(TAG, "Stoppe WiFi");
    return esp_wifi_stop();
}

esp_err_t wifi_manager_start_ap(void)
{
    ESP_LOGI(TAG, "Starte Hotspot: %s", CONFIG_BSC_DEFAULT_AP_SSID);

    // Stoppen falls bereits aktiv
    esp_wifi_stop();

    // AP-IP konfigurieren
    esp_netif_ip_info_t ip_info;
    esp_ip4addr_aton("192.168.4.1", &ip_info.ip);
    esp_ip4addr_aton("192.168.4.1", &ip_info.gw);
    esp_ip4addr_aton("255.255.255.0", &ip_info.netmask);

    esp_netif_dhcps_stop(s_netif_ap);
    esp_netif_set_ip_info(s_netif_ap, &ip_info);
    esp_netif_dhcps_start(s_netif_ap);

    // WiFi AP Konfiguration
    wifi_config_t wifi_config = {
        .ap = {
            .ssid_len = strlen(CONFIG_BSC_DEFAULT_AP_SSID),
            .channel = 1,
            .max_connection = 4,
            .authmode = WIFI_AUTH_WPA2_PSK,
            .pmf_cfg = {
                .required = false,
            },
        },
    };

    strncpy((char*)wifi_config.ap.ssid, CONFIG_BSC_DEFAULT_AP_SSID, sizeof(wifi_config.ap.ssid));
    strncpy((char*)wifi_config.ap.password, CONFIG_BSC_DEFAULT_AP_PASSWORD, sizeof(wifi_config.ap.password));

    if (strlen(CONFIG_BSC_DEFAULT_AP_PASSWORD) < 8) {
        wifi_config.ap.authmode = WIFI_AUTH_OPEN;
    }

    ESP_ERROR_CHECK(esp_wifi_set_mode(WIFI_MODE_AP));
    ESP_ERROR_CHECK(esp_wifi_set_config(WIFI_IF_AP, &wifi_config));
    ESP_ERROR_CHECK(esp_wifi_start());

    ESP_LOGI(TAG, "Hotspot gestartet. SSID: %s, Passwort: %s",
             CONFIG_BSC_DEFAULT_AP_SSID, CONFIG_BSC_DEFAULT_AP_PASSWORD);

    return ESP_OK;
}

esp_err_t wifi_manager_connect(const wifi_config_data_t* config)
{
    if (!config || strlen(config->ssid) == 0) {
        ESP_LOGE(TAG, "Ungültige WiFi-Konfiguration");
        return ESP_ERR_INVALID_ARG;
    }

    ESP_LOGI(TAG, "Verbinde mit WLAN: %s", config->ssid);

    // Stoppen falls bereits aktiv
    esp_wifi_stop();

    // Static IP konfigurieren wenn gewünscht
    if (config->ip_mode == IP_MODE_STATIC && strlen(config->static_ip) > 0) {
        ESP_LOGI(TAG, "Verwende statische IP: %s", config->static_ip);

        esp_netif_dhcpc_stop(s_netif_sta);

        esp_netif_ip_info_t ip_info;
        memset(&ip_info, 0, sizeof(ip_info));

        esp_ip4addr_aton(config->static_ip, &ip_info.ip);
        esp_ip4addr_aton(config->gateway, &ip_info.gw);
        esp_ip4addr_aton(config->netmask, &ip_info.netmask);

        esp_netif_set_ip_info(s_netif_sta, &ip_info);

        // DNS konfigurieren wenn vorhanden
        if (strlen(config->dns) > 0) {
            esp_netif_dns_info_t dns;
            esp_ip4addr_aton(config->dns, &dns.ip.u_addr.ip4);
            dns.ip.type = ESP_IPADDR_TYPE_V4;
            esp_netif_set_dns_info(s_netif_sta, ESP_NETIF_DNS_MAIN, &dns);
        }
    } else {
        esp_netif_dhcpc_start(s_netif_sta);
    }

    // WiFi STA Konfiguration
    wifi_config_t wifi_config = {
        .sta = {
            .threshold.authmode = WIFI_AUTH_WPA2_PSK,
            .sae_pwe_h2e = WPA3_SAE_PWE_BOTH,
        },
    };

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

    s_retry_count = 0;

    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());

    return ESP_OK;
}

esp_err_t wifi_manager_disconnect(void)
{
    ESP_LOGI(TAG, "Trenne WiFi-Verbindung");
    esp_wifi_disconnect();
    return wifi_manager_start_ap();
}

wifi_state_t wifi_manager_get_state(void)
{
    return s_state;
}

esp_err_t wifi_manager_get_ip(char* ip_str, size_t len)
{
    esp_netif_ip_info_t ip_info;
    esp_netif_t* netif = (s_state == WIFI_STATE_AP_STARTED) ? s_netif_ap : s_netif_sta;

    esp_err_t err = esp_netif_get_ip_info(netif, &ip_info);
    if (err != ESP_OK) return err;

    snprintf(ip_str, len, IPSTR, IP2STR(&ip_info.ip));
    return ESP_OK;
}

esp_err_t wifi_manager_scan(void)
{
    ESP_LOGI(TAG, "Starte WLAN-Scan...");

    // Scan-Konfiguration
    wifi_scan_config_t scan_config = {
        .ssid = NULL,
        .bssid = NULL,
        .channel = 0,
        .show_hidden = false,
        .scan_type = WIFI_SCAN_TYPE_ACTIVE,
        .scan_time.active.min = 100,
        .scan_time.active.max = 300,
    };

    return esp_wifi_scan_start(&scan_config, false);
}

esp_err_t wifi_manager_register_callback(wifi_event_callback_t callback)
{
    s_callback = callback;
    return ESP_OK;
}

esp_netif_t* wifi_manager_get_netif(void)
{
    return (s_state == WIFI_STATE_AP_STARTED) ? s_netif_ap : s_netif_sta;
}