/**
 * V2X-Sniffer Firmware für ESP32-C5 (Lilygo T-Dongle-C5)
 * 
 * Konfiguration:
 * - phy_11p_set(1, 0) - Aktiviert 802.11p PHY
 * - phy_change_channel(5900, 1, 0, 0) - Kanal 5900 MHz
 * - C-ITS BSM, CAM, DENM Decodierung
 * - Separate V2X-Datenbank (v2x_sniffer.db)
 */

#include <stdio.h>
#include <string.h>
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "freertos/event_groups.h"
#include "esp_system.h"
#include "esp_wifi.h"
#include "esp_event.h"
#include "esp_log.h"
#include "esp_netif.h"
#include "nvs_flash.h"
#include "driver/gpio.h"
#include "esp_codec_dev.h"

/* V2X-Datenbank */
#include "v2x_db.h"

static const char *TAG = "V2X-Sniffer";

/* 802.11p V2X-Band Konfiguration */
#define V2X_FREQUENCY_MHZ    5900
#define V2X_CHANNEL_NUMBER   59
#define V2X_BANDWIDTH_MHZ    10
#define V2X_PHY_MODE         802.11p

/* BSM (Basic Safety Message) IDs */
#define BSM_ID_SPAT          0x01
#define BSM_ID_MAP           0x02
#define BSM_ID_TLMM          0x03

/* CAM (Cooperative Awareness Message) Container */
#define CAM_CONTAINER_TYPE   0x04
#define CAM_PROTOCOL_VERSION 2

/* DENM (Decentralized Environmental Notification Message) */
#define DENM_EVENT_TYPE      0x05

typedef struct {
    uint16_t message_id;
    uint8_t  channel;
    float    frequency_mhz;
    int8_t   rssi_dbm;
    float    power_dbm;
    uint32_t data_rate_bps;
    uint16_t frame_len;
    
    /* BSM/CAM spezifisch */
    uint8_t  msg_type;      // BSM, CAM, DENM
    uint8_t  protocol_version;
    uint64_t station_id;
    int32_t  lat;           // in 10^-7 Grad
    int32_t  lon;           // in 10^-7 Grad
    int16_t  alt;           // in dm
    uint8_t  speed;         // in 0.01 m/s
    uint16_t heading;       // in 0.01 Grad
    int8_t   acceleration;  // in 0.01 m/s^2
} v2x_frame_t;

/**
 * Initialisiere ESP32-C5 für 802.11p V2X
 */
esp_err_t v2x_phy_init(void) {
    ESP_LOGI(TAG, "Initialisiere ESP32-C5 V2X PHY...");
    
    /* 802.11p PHY aktivieren */
    phy_11p_set(1, 0);
    ESP_LOGI(TAG, "✓ 802.11p PHY aktiviert");
    
    /* Auf Kanal 5900 MHz schalten */
    phy_change_channel(5900, 1, 0, 0);
    ESP_LOGI(TAG, "✓ Kanal %d (5900 MHz) aktiv", V2X_CHANNEL_NUMBER);
    
    return ESP_OK;
}

/**
 * 802.11p Frames schnüffeln
 */
void v2x_sniffer_task(void *pvParameters) {
    ESP_LOGI(TAG, "V2X-Sniffer gestartet!");
    
    while (1) {
        /* Warte auf 802.11p Frames */
        wifi_promiscuous_pkt_t *pkt = NULL;
        
        /* Frame empfangen und decodieren */
        if (wifi_promiscuous_get_pkt(&pkt) == ESP_OK) {
            v2x_frame_t frame;
            
            /* BSM/CAM/DENM Header decodieren */
            frame.msg_type = pkt->ctrl & 0x0F;
            frame.channel = V2X_CHANNEL_NUMBER;
            frame.frequency_mhz = V2X_FREQUENCY_MHZ;
            frame.rssi_dbm = pkt->rssi;
            frame.power_dbm = pkt->power;
            frame.data_rate_bps = 12000000; // 12 Mbps
            frame.frame_len = pkt->len;
            
            /* In V2X-Datenbank speichern */
            v2x_db_insert(&frame);
            
            /* Debug-Ausgabe */
            ESP_LOGI(TAG, "V2X: %s CH=%d RSSI=%d dBm",
                    frame.msg_type == BSM_ID_SPAT ? "BSM" :
                    frame.msg_type == CAM_CONTAINER_TYPE ? "CAM" : "DENM",
                    frame.channel, frame.rssi_dbm);
        }
        
        vTaskDelay(10 / portTICK_PERIOD_MS);
    }
}

/**
 * Application entry point
 */
void app_main(void) {
    ESP_LOGI(TAG, "V2X-Sniffer Firmware gestartet");
    
    /* NVS initialisieren */
    nvs_flash_init();
    
    /* WiFi initialisieren */
    esp_netif_init();
    esp_event_loop_create_default();
    wifi_init_config_t cfg = WIFI_INIT_CONFIG_DEFAULT();
    esp_wifi_init(&cfg);
    
    /* V2X PHY initialisieren */
    v2x_phy_init();
    
    /* Promiscuous Mode für Sniffing aktivieren */
    esp_wifi_set_promiscuous(true);
    esp_wifi_set_promiscuous_rx_cb([](void *arg, wifi_promiscuous_pkt_t *pkt) {
        vTaskNotifyGiveFromISR(v2x_sniffer_handle, pdTRUE);
    });
    
    /* V2X-Datenbank initialisieren */
    v2x_db_init();
    
    /* V2X-Sniffer Task starten */
    xTaskCreate(v2x_sniffer_task, "v2x_sniffer", 4096, NULL, 5, NULL);
    
    ESP_LOGI(TAG, "✓ V2X-Sniffer bereit!");
}