#include <stdio.h>
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "driver/gpio.h"
#include "esp_rom_sys.h"
#include "esp_log.h"
#include "dht22.h"
#include "GPS_parser.h"
#include "driver/uart.h"
#include <string.h>
#include <sys/unistd.h>
#include <sys/stat.h>
#include "esp_vfs_fat.h"
#include "sdmmc_cmd.h"
#include "ssd1306.h"
#include <driver/i2c_master.h>
#include "math.h"
#include "string.h"
#include "esp_wifi.h"
#include "esp_netif.h"
#include "esp_event.h"
#include "esp_http_server.h"
#include "lwip/inet.h"
#include "sys/stat.h"

const char *DHT_TAG = "DHT22";
const char *GPS_TAG = "GPS_PARSER";
const char *SD_TAG = "SD_CARD";
const char *OLED_TAG = "SSD1306OLED";
const char *GEN_TAG = "General";

#define MOUNT_POINT "/sdcard"

#define PIN_NUM_MISO  CONFIG_PIN_MISO
#define PIN_NUM_MOSI  CONFIG_PIN_MOSI
#define PIN_NUM_CLK   CONFIG_PIN_CLK
#define PIN_NUM_CS    CONFIG_PIN_CS

#define PIN_NUM_SDA CONFIG_PIN_SDA
#define PIN_NUM_SCL CONFIG_PIN_SCL

#define PIN_TX GPIO_NUM_17
#define PIN_RX GPIO_NUM_16

//definicion de tiempos de pulsacion
#define PULSACION_LARGA_MS 2000
#define DURACION_WATCHDOG_MS 10000

#define MEASUREMENT_INTERVAL_S 1

#define DEG2RAD (M_PI/180.0)

const int uart_buffer_size = (1024 * 2);
int length = 0;

uint8_t data;

static gps_parser_t gps;

static httpd_handle_t http_server = NULL;
static esp_netif_t *ap_netif = NULL;
static bool wifiActivado = false;
static uint32_t wifiLastActivity = 0;

extern char filename[13]; // tu archivo gpx
const char *apSSID = "MiAP";
const char *apPassword = "password123";

struct SensorData {
  double latitude;
  double longitude;
  float altura;
  char tiempo[64];
  float velocidad;
  float temperature;
  float humidity;
  float pressure;
};

struct SensorData latestData;
struct SensorData datosAntiguos;

SemaphoreHandle_t dataMutex; // Mutex para proteger el acceso a latestData
SemaphoreHandle_t buttonSemaphore; // Semáforo para la tarea del botón

bool grabando = false; //inicia apagado
bool finalizado = true; //indica que no hay ninguna grabacion ni iniciada ni pausada
TaskHandle_t medicionesHandle = NULL; //para suspend/resume
int pantallaEstado_grab = -1; //maquina de estados cuando se graba ruta
int pantallaEstado_menu = -1; //maquina de estados cuando no se esta grabando ruta
float distancia_total = 0.0;
volatile unsigned long ignore_isr_until = 0; //para debounce

char filename[13] = "/panchas.gpx";

ssd1306_handle_t d = NULL;

const char mount_point[] = MOUNT_POINT;

void OLED_test(){

    i2c_master_bus_handle_t i2c_bus = i2c_bus0_init(PIN_NUM_SDA, PIN_NUM_SCL, 400000);

    ssd1306_config_t cfg = {
        .width  = 128,
        .height = 64,
        .fb     = NULL, // let driver allocate internally
        .fb_len = 0,
        .iface.i2c =
            {
                .port     = I2C_NUM_0,
                .addr     = 0x3C,        // typical SSD1306 I2C address
                .rst_gpio = GPIO_NUM_NC, // no reset pin
            },
    };

    ESP_ERROR_CHECK(ssd1306_new_i2c(&cfg, &d));

    ESP_ERROR_CHECK(ssd1306_clear(d));

    ESP_ERROR_CHECK(ssd1306_draw_rect(d, cfg.width / 2 - 50, cfg.height / 2 - 10, 100, 20, false));
    
    ESP_ERROR_CHECK(ssd1306_display(d));

    ESP_ERROR_CHECK(ssd1306_draw_circle(d, cfg.width / 2, cfg.height / 2, 20, true));

    ESP_ERROR_CHECK(ssd1306_display(d));
    
    ESP_ERROR_CHECK(ssd1306_draw_text_scaled(d, 0, 0, "Iniciando...", true, 1));

    ESP_ERROR_CHECK(ssd1306_display(d));

    vTaskDelay(pdMS_TO_TICKS(1000));

}

void OLED_print(const char *line1, const char *line2){
    
    ESP_ERROR_CHECK(ssd1306_clear(d));

    ESP_ERROR_CHECK(ssd1306_draw_text_scaled(d, 0, 0, line1, true, 2));
    ESP_ERROR_CHECK(ssd1306_draw_text_scaled(d, 0, 40, line2, true, 2));

    ESP_ERROR_CHECK(ssd1306_display(d));

}

void DHT_test (){
    float t;
    float h;

    esp_err_t err = dht_attach_pin();

    if (err != ESP_OK) {
        OLED_print("DHT22", "Error");
        ESP_LOGE(DHT_TAG, "Failed to attach DHT pin: %s", esp_err_to_name(err));
        vTaskDelay(pdMS_TO_TICKS(5000)); // Wait for 5 seconds before retrying
        DHT_test();  //Reintentar
    }
    
    err = dht_read(&t, &h);

    if (err != ESP_OK) {
        OLED_print("DHT22", "Error");
        ESP_LOGE(DHT_TAG, "Failed to read DHT : %s", esp_err_to_name(err));
        vTaskDelay(pdMS_TO_TICKS(5000)); // Wait for 5 seconds before retrying
        DHT_test();  //Reintentar
    }

    else OLED_print("DHT22", "Correcto");
}

void SD_test(){

    esp_vfs_fat_sdmmc_mount_config_t mount_config = {
        .format_if_mount_failed = false,
        .max_files = 5,
        .allocation_unit_size = 16 * 1024
    };

    sdmmc_card_t *card;

    sdmmc_host_t host = SDSPI_HOST_DEFAULT();
    host.max_freq_khz = 9000; //a mas freq no funciona, porque pipas

    spi_bus_config_t bus_cfg = {
        .mosi_io_num = PIN_NUM_MOSI,
        .miso_io_num = PIN_NUM_MISO,
        .sclk_io_num = PIN_NUM_CLK,
        .quadwp_io_num = -1,
        .quadhd_io_num = -1,
        .max_transfer_sz = 4092,
    };

    esp_err_t ret = spi_bus_initialize(host.slot, &bus_cfg, SDSPI_DEFAULT_DMA);
    if (ret != ESP_OK) {
        ESP_LOGE(SD_TAG, "Failed to initialize bus.");
        return;
    }

    sdspi_device_config_t slot_config = SDSPI_DEVICE_CONFIG_DEFAULT();
    slot_config.gpio_cs = PIN_NUM_CS;
    slot_config.host_id = host.slot;

    ESP_LOGI(SD_TAG, "Mounting filesystem");

    while((ret = esp_vfs_fat_sdspi_mount(mount_point, &host, &slot_config, &mount_config, &card)) != ESP_OK){
        if (ret == ESP_FAIL) {
            ESP_LOGE(SD_TAG, "Failed to mount filesystem. "
                     "If you want the card to be formatted, set the CONFIG_EXAMPLE_FORMAT_IF_MOUNT_FAILED menuconfig option.");
            OLED_print("Error SD", "Prueba a reinsertar");
        } else {
            ESP_LOGE(SD_TAG, "Failed to initialize the card (%s). "
                     "Make sure SD card lines have pull-up resistors in place.", esp_err_to_name(ret));
            OLED_print("Error SD", esp_err_to_name(ret));
        }
        vTaskDelay(pdMS_TO_TICKS(1000));
    }

    ESP_LOGI(SD_TAG, "Filesystem mounted");

    OLED_print("SD correcta","");

    // Card has been initialized, print its properties
    sdmmc_card_print_info(stdout, card);


    
}

void GPS_test_wait(){

    // Iniciar Serial2 para GPS
    bool fixObtained = false;

    uart_configurator();

    gps_parser_init(&gps);

    while (!fixObtained) {
        while (uart_read_bytes(UART_NUM_2, &data, 1, 0)){
            gps_parser_encode(&gps, data);
        }
        if (gps_location_is_valid(&gps.location) && gps_date_is_valid(&gps.date) && gps_time_is_valid(&gps.time)) {
            fixObtained = true;
            break;
        }
        vTaskDelay(pdMS_TO_TICKS(300));
        OLED_print("GPS", "Esperando");
        vTaskDelay(pdMS_TO_TICKS(300));
        OLED_print("GPS", "Esperando .");
        vTaskDelay(pdMS_TO_TICKS(300));
        OLED_print("GPS", "Esperando ..");
        vTaskDelay(pdMS_TO_TICKS(300));
        OLED_print("GPS", "Esperando ...");
    }

    OLED_print("GPS", "Encontrado");

}

float calcular_delta_dist(float lat1, float  long1, float lat2, float long2){
  float R = 6371000.0; // Radio de la Tierra en km
  float delta_lat = (lat2 - lat1) * DEG2RAD;
  float delta_long = (long2 - long1) * DEG2RAD;
  lat1 = lat1 * DEG2RAD;
  lat2 = lat2 * DEG2RAD;
  float a = sin(delta_lat/2)*sin(delta_lat/2)+cos(lat1)*cos(lat2)*sin(delta_long/2)*sin(delta_long/2);
  float c = 2 * atan2(sqrt(a),sqrt(1-a));
  return R * c;  //En m
}

void task_mediciones(void *pvParameters) {
    TickType_t xLastWakeTime = xTaskGetTickCount();
    char buffer[50];
    while(1) {
        unsigned long startMillis = pdTICKS_TO_MS(xTaskGetTickCount());
        // se leen los valores antes de utilizar el semaphore    
        while (uart_read_bytes(UART_NUM_2, &data, 1, 0)){
            gps_parser_encode(&gps, data);
        }

        float new_latitude = gps_location_lat(&gps.location);
        float new_longitude = gps_location_lng(&gps.location);
        float new_altitude = 0.0; //gps.altitude.meters(); falta por implementar en la libreria del gps
        int new_fecha_len = snprintf(buffer, sizeof(buffer), "%d-%02d-%02dT%02d:%02d:%02d.%03d", gps_date_year(&gps.date), gps_date_month(&gps.date),
                                    gps_date_day(&gps.date), gps_time_hour(&gps.time), gps_time_minute(&gps.time), 
                                    gps_time_second(&gps.time), gps_time_centisecond(&gps.time));
        if (new_fecha_len < 0) {
            buffer[0] = '\0';
        }
        float new_temp = 0.0;
        float new_hum = 0.0;
        dht_read(&new_temp, &new_hum);
        float new_press = 0.0; // Placeholder, no hay sensor de presión 
        
        float distancia_ciclo = calcular_delta_dist(datosAntiguos.latitude, datosAntiguos.longitude, new_latitude, new_longitude);
        distancia_total += distancia_ciclo;
        float new_speed = distancia_ciclo / MEASUREMENT_INTERVAL_S * 3.6;
        

        if (xSemaphoreTake(dataMutex, portMAX_DELAY) == pdTRUE) {
            latestData.latitude = new_latitude;
            latestData.longitude = new_longitude;
            latestData.altura = new_altitude;
            strncpy(latestData.tiempo, buffer, sizeof(latestData.tiempo) - 1);
            latestData.tiempo[sizeof(latestData.tiempo) - 1] = '\0';
            latestData.velocidad = new_speed;
            latestData.temperature = new_temp;
            latestData.humidity = new_hum;
            latestData.pressure = new_press;
            datosAntiguos = latestData;
            xSemaphoreGive(dataMutex);
        }

        FILE *f = fopen(filename, "a");
        if (f) {
            //Crear la string para escribir en el archivo
            fprintf(f, "\t\t\t<trkpt lat=\"");
            fprintf(f, "%2.4f", datosAntiguos.latitude);
            fprintf(f, "\" lon=\"");
            fprintf(f, "%2.4f", datosAntiguos.longitude);
            fprintf(f, "\">\n");

            fprintf(f, "\t\t\t\t<ele>");
            fprintf(f, "%f", datosAntiguos.altura);
            fprintf(f, "</ele>\n");

            fprintf(f, "\t\t\t\t<time>");
            fprintf(f, "%s", datosAntiguos.tiempo);
            fprintf(f, "</time>\n");

            fprintf(f, "\t\t\t\t<speed>");
            fprintf(f, "%f", datosAntiguos.velocidad);
            fprintf(f, "</speed>\n");

            fprintf(f, "\t\t\t\t<extensions>\n");
            fprintf(f, "\t\t\t\t\t<gpxtpx:TrackPointExtension>\n");
            fprintf(f, "\t\t\t\t\t\t<gpxtpx:atemp>");
            fprintf(f, "%f", datosAntiguos.temperature);
            fprintf(f, "</gpxtpx:atemp>\n");
            fprintf(f, "\t\t\t\t\t</gpxtpx:TrackPointExtension>\n");

            fprintf(f, "\t\t\t\t\t<custom:humidity>");
            fprintf(f, "%f", datosAntiguos.humidity);
            fprintf(f, "</custom:humidity>\n");

            fprintf(f, "\t\t\t\t\t<custom:pressure>");
            fprintf(f, "%f", datosAntiguos.pressure);
            fprintf(f, "</custom:pressure>\n");

            fprintf(f, "\t\t\t\t</extensions>\n");
            fprintf(f, "\t\t\t</trkpt>\n");
            
            fclose(f);
        }
        unsigned long elapsedMillis = pdTICKS_TO_MS(xTaskGetTickCount()) - startMillis;
        ESP_LOGI(GEN_TAG, "Elapsed millis: %d.", elapsedMillis);

        vTaskDelayUntil(&xLastWakeTime, pdMS_TO_TICKS(MEASUREMENT_INTERVAL_S*1000)); // Espera x*1000 milisegundos
        
    }
}

void crear_archivo(){
    int num = 1;

    sprintf(filename, MOUNT_POINT"/data%03d.gpx", num);

    FILE *f = fopen(filename, "r");

    while (f != NULL) {
        num++;
        sprintf(filename, MOUNT_POINT"/data%03d.gpx", num);
        FILE *f = fopen(filename, "r");
    }

    FILE *f = fopen(filename, "w");

    char buffer[50];

    if (f) {
        fprintf(f, "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n"
                    "<gpx creator=\"ESP32 GPS LOGGER\" version=\"1.1\"\n"
                    "\txmlns=\"http://www.topografix.com/GPX/1/1\"\n"
                    "\txmlns:xsi=\"http://www.w3.org/2001/XMLSchema-instance\"\n"
                    "\txmlns:gpxtpx=\"http://www.garmin.com/xmlschemas/TrackPointExtension/v2\"\n"
                    "\txmlns:gpxdata=\"http://www.cluetrust.com/XML/GPXDATA/1/0\"\n"
                    "\txsi:schemaLocation=\"http://www.topografix.com/GPX/1/1 http://www.topografix.com/GPX/1/1/gpx.xsd\">\n"
                    "\t<metadata>\n"
                    "\t\t<name>Ruta grabada con ESP32 GPS Logger</name>\n"
                    "\t\t<time>\n");
        int new_fecha_len = snprintf(buffer, sizeof(buffer), "%d-%02d-%02dT%02d:%02d:%02d.%03d", gps_date_year(&gps.date), gps_date_month(&gps.date),
                                    gps_date_day(&gps.date), gps_time_hour(&gps.time), gps_time_minute(&gps.time), 
                                    gps_time_second(&gps.time), gps_time_centisecond(&gps.time));
        if (new_fecha_len < 0) {
            buffer[0] = '\0';
        }
        fprintf(f, "%s", buffer);
        fprintf(f, "</time>\n\t</metadata>\n"
                    "\t<trk>\n"
                    "\t\t<name>Rutita</name>\n"
                    "\t\t<type>hiking</type>\n"
                    "\t\t<trkseg>\n");
        fclose(f);
    } else {
        OLED_print("Error","creando archivo");
        vTaskDelay(pdMS_TO_TICKS(2000));
        crear_archivo();
    }
}

void cerrar_archivo() {
    FILE *f = fopen(filename, "w");
    if (f){
        fprintf(f, "\t\t</trkseg>\n\t</trk>\n</gpx>");
        fclose(f);
    }
    //int num = 1;
    //sprintf(filename, "/data%03d.gpx", num);
    //while (SD.exists(filename)) {
    //  num++;
    //  sprintf(filename, "/data%03d.gpx", num);
    //}
}

void activarWiFi(void)
{
    OLED_print("WiFi", "Activando...");

    ESP_ERROR_CHECK(wifi_ap_init());

    char ip_str[16] = {0};
    get_ap_ip(ip_str, sizeof(ip_str));
    OLED_print("WiFi Activo", ip_str);

    vTaskDelay(pdMS_TO_TICKS(2000));

    ESP_ERROR_CHECK(iniciar_servidor_http());

    wifiActivado = true;
    wifiLastActivity = xTaskGetTickCount();
}

void desactivarWiFi(void)
{
    if (http_server) {
        httpd_stop(http_server);
        http_server = NULL;
    }

    ESP_ERROR_CHECK(esp_wifi_stop());
    ESP_ERROR_CHECK(esp_wifi_deinit());

    if (ap_netif) {
        esp_netif_destroy(ap_netif);
        ap_netif = NULL;
    }

    wifiActivado = false;
    OLED_print("WiFi", "Apagado");
}

void app_main(void)
{
    // Initialize DHT22 sensor
    /*
    float temperature;
    float humidity;
    esp_err_t err = dht_attach_pin();
    if (err != ESP_OK) {
        ESP_LOGE(DHT_TAG, "Failed to attach DHT pin: %s", esp_err_to_name(err));
        vTaskDelay(pdMS_TO_TICKS(5000)); // Wait for 5 seconds before retrying
        return;
    }
    vTaskDelay(pdMS_TO_TICKS(2000)); // Wait for 2 seconds before starting the main loop
    while (1) {
        if (dht_read(&temperature, &humidity) == ESP_OK) {
            ESP_LOGI(DHT_TAG, "Temperature: %.1f°C, Humidity: %.1f%%", temperature, humidity);
        } else {
            ESP_LOGE(DHT_TAG, "Failed to read from DHT22 sensor");
        }
        vTaskDelay(pdMS_TO_TICKS(5000)); // Wait for 5 seconds before the next reading
    }
    */
    // Initialize GPS parser
    /*
    uart_configurator();
    double latitude, longitude;
    gps_parser_init(&gps);
    while(1){
        while (uart_read_bytes(UART_NUM_2, &data, 1, 0)){
            gps_parser_encode(&gps, data);
        }
        if (gps_location_is_valid(&gps.location)) {
            double lat = gps_location_lat(&gps.location);
            double lng = gps_location_lng(&gps.location);
            ESP_LOGI(GPS_TAG, "Lat: %.8f, Lng: %.8f", lat, lng);
        }

        if (gps_date_is_valid(&gps.date) && gps_time_is_valid(&gps.time)) {
            ESP_LOGI(GPS_TAG, "Fecha: %02u/%02u/%04u Hora: %02u:%02u:%02u\n",
                    gps_date_day(&gps.date),
                    gps_date_month(&gps.date),
                    gps_date_year(&gps.date),
                    gps_time_hour(&gps.time),
                    gps_time_minute(&gps.time),
                    gps_time_second(&gps.time));
        }
        vTaskDelay(pdMS_TO_TICKS(2000)); // Wait for 1 second before the next reading
    }
    */

    // Initialize SD card
    /*
    esp_vfs_fat_sdmmc_mount_config_t mount_config = {
        .format_if_mount_failed = false,
        .max_files = 5,
        .allocation_unit_size = 16 * 1024
    };

    sdmmc_card_t *card;

    const char mount_point[] = MOUNT_POINT;

    sdmmc_host_t host = SDSPI_HOST_DEFAULT();
    host.max_freq_khz = 9000; //a mas freq no funciona, porque pipas

    spi_bus_config_t bus_cfg = {
        .mosi_io_num = PIN_NUM_MOSI,
        .miso_io_num = PIN_NUM_MISO,
        .sclk_io_num = PIN_NUM_CLK,
        .quadwp_io_num = -1,
        .quadhd_io_num = -1,
        .max_transfer_sz = 4092,
    };

    esp_err_t ret = spi_bus_initialize(host.slot, &bus_cfg, SDSPI_DEFAULT_DMA);
    if (ret != ESP_OK) {
        ESP_LOGE(SD_TAG, "Failed to initialize bus.");
        return;
    }

    gpio_set_pull_mode(PIN_NUM_MISO, GPIO_PULLUP_ONLY);

    sdspi_device_config_t slot_config = SDSPI_DEVICE_CONFIG_DEFAULT();
    slot_config.gpio_cs = PIN_NUM_CS;
    slot_config.host_id = host.slot;

    ESP_LOGI(SD_TAG, "Mounting filesystem");
    ret = esp_vfs_fat_sdspi_mount(mount_point, &host, &slot_config, &mount_config, &card);

    if (ret != ESP_OK) {
        if (ret == ESP_FAIL) {
            ESP_LOGE(SD_TAG, "Failed to mount filesystem. "
                     "If you want the card to be formatted, set the CONFIG_EXAMPLE_FORMAT_IF_MOUNT_FAILED menuconfig option.");
        } else {
            ESP_LOGE(SD_TAG, "Failed to initialize the card (%s). "
                     "Make sure SD card lines have pull-up resistors in place.", esp_err_to_name(ret));
        }
        return;
    }
    ESP_LOGI(SD_TAG, "Filesystem mounted");

    // Card has been initialized, print its properties
    sdmmc_card_print_info(stdout, card);

    const char *file_foo = MOUNT_POINT"/foo.txt";

    // Check if destination file exists before renaming
    struct stat st;
    if (stat(file_foo, &st) == 0) {
        // Delete it if it exists
        unlink(file_foo);
    }

    const char *file_nihao = MOUNT_POINT"/nihao.txt";

    // All done, unmount partition and disable SPI peripheral
    esp_vfs_fat_sdcard_unmount(mount_point, card);
    ESP_LOGI(SD_TAG, "Card unmounted");

    //deinitialize the bus after all devices are removed
    spi_bus_free(host.slot);
    */

    // Initialize display
    /*
    i2c_master_bus_handle_t i2c_bus =
        i2c_bus0_init(GPIO_NUM_21, GPIO_NUM_22, 400000);

    ssd1306_config_t cfg = {
        .width  = 128,
        .height = 64,
        .fb     = NULL, // let driver allocate internally
        .fb_len = 0,
        .iface.i2c =
            {
                .port     = I2C_NUM_0,
                .addr     = 0x3C,        // typical SSD1306 I2C address
                .rst_gpio = GPIO_NUM_NC, // no reset pin
            },
    };

    ssd1306_handle_t d = NULL;
    ESP_ERROR_CHECK(ssd1306_new_i2c(&cfg, &d));

    // ----- Clear screen -----
    ESP_ERROR_CHECK(ssd1306_clear(d));

    // ----- Draw pixels in corners of screen -----
    ESP_ERROR_CHECK(ssd1306_draw_pixel(d, 0, 0, true));
    ESP_ERROR_CHECK(ssd1306_draw_pixel(d, cfg.width - 1, 0, true));
    ESP_ERROR_CHECK(ssd1306_draw_pixel(d, 0, cfg.height - 1, true));
    ESP_ERROR_CHECK(ssd1306_draw_pixel(d, cfg.width - 1, cfg.height - 1, true));

    // ----- Draw rectangles -----
    ESP_ERROR_CHECK(ssd1306_draw_rect(d, 2, 2, 40, 20, false));
    ESP_ERROR_CHECK(ssd1306_draw_rect(d, 2, 24, 32, 16, true));

    // ----- Draw circles -----
    ESP_ERROR_CHECK(ssd1306_draw_circle(d, 32, 52, 8, true));
    ESP_ERROR_CHECK(ssd1306_draw_circle(d, 100, 52, 4, false));

    // ----- Draw lines -----
    ESP_ERROR_CHECK(ssd1306_draw_line(d, 2, 2, 40, 20, true));
    ESP_ERROR_CHECK(ssd1306_draw_line(d, 32, 52, 100, 52, true));

    // ----- Draw text -----
    ESP_ERROR_CHECK(ssd1306_draw_text(d, 48, 2, "OK!", true));
    ESP_ERROR_CHECK(
        ssd1306_draw_text_scaled(d, 48, 10, "Hello\nWorld!", true, 2));

    ESP_ERROR_CHECK(ssd1306_display(d));

    ESP_LOGI(OLED_TAG, "Display updated successfully.");
    */
}


void uart_configurator() {
    // Configure UART parameters
    uart_config_t uart_config = {
        .baud_rate = 115200,
        .data_bits = UART_DATA_8_BITS,
        .parity = UART_PARITY_DISABLE,
        .stop_bits = UART_STOP_BITS_1,
        .flow_ctrl = UART_HW_FLOWCTRL_DISABLE
    };
    QueueHandle_t uart_queue;
    // Install UART driver using an event queue here
    ESP_ERROR_CHECK(uart_driver_install(UART_NUM_2, uart_buffer_size, uart_buffer_size, 10, &uart_queue, 0));
    ESP_ERROR_CHECK(uart_param_config(UART_NUM_2, &uart_config));
    ESP_ERROR_CHECK(uart_set_pin(UART_NUM_2, PIN_TX, PIN_RX, UART_PIN_NO_CHANGE, UART_PIN_NO_CHANGE));
}

static esp_err_t s_example_write_file(const char *path, char *data)
{
    ESP_LOGI(SD_TAG, "Opening file %s", path);
    FILE *f = fopen(path, "w");
    if (f == NULL) {
        ESP_LOGE(SD_TAG, "Failed to open file for writing");
        return ESP_FAIL;
    }
    fprintf(f, data);
    fclose(f);
    ESP_LOGI(SD_TAG, "File written");

    return ESP_OK;
}

// Init i2c
static i2c_master_bus_handle_t i2c_bus0_init(gpio_num_t sda, gpio_num_t scl, uint32_t hz) {
    i2c_master_bus_config_t bus_cfg = {
        .i2c_port                     = I2C_NUM_0,
        .sda_io_num                   = sda,
        .scl_io_num                   = scl,
        .clk_source                   = I2C_CLK_SRC_DEFAULT,
        .glitch_ignore_cnt            = 0,
        .flags.enable_internal_pullup = true,
    };
    i2c_master_bus_handle_t bus = NULL;
    ESP_ERROR_CHECK(i2c_new_master_bus(&bus_cfg, &bus));
    // NOTE: per-device speed is set when adding the device (in driver bind).
    return bus;
}

static esp_err_t wifi_ap_init(void)
{
    esp_err_t err;

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

    ap_netif = esp_netif_create_default_wifi_ap();
    wifi_init_config_t cfg = WIFI_INIT_CONFIG_DEFAULT();
    ESP_ERROR_CHECK(esp_wifi_init(&cfg));
    ESP_ERROR_CHECK(esp_wifi_set_mode(WIFI_MODE_AP));

    wifi_config_t wifi_config = {
        .ap = {
            .ssid = "",
            .ssid_len = 0,
            .channel = 1,
            .password = "",
            .max_connection = 4,
            .authmode = WIFI_AUTH_WPA_WPA2_PSK,
        },
    };

    strncpy((char *)wifi_config.ap.ssid, apSSID, sizeof(wifi_config.ap.ssid) - 1);
    strncpy((char *)wifi_config.ap.password, apPassword, sizeof(wifi_config.ap.password) - 1);

    if (strlen(apPassword) == 0) {
        wifi_config.ap.authmode = WIFI_AUTH_OPEN;
    }

    ESP_ERROR_CHECK(esp_wifi_set_config(ESP_IF_WIFI_AP, &wifi_config));
    ESP_ERROR_CHECK(esp_wifi_start());
    return ESP_OK;
}

static esp_err_t get_ap_ip(char *out_ip, size_t len)
{
    esp_netif_ip_info_t ip_info;
    if (ap_netif == NULL) {
        return ESP_ERR_INVALID_STATE;
    }
    ESP_ERROR_CHECK(esp_netif_get_ip_info(ap_netif, &ip_info));
    inet_ntoa_r(ip_info.ip, out_ip, len);
    return ESP_OK;
}

static esp_err_t root_get_handler(httpd_req_t *req)
{
    wifiLastActivity = xTaskGetTickCount();

    char ip_str[16] = {0};
    get_ap_ip(ip_str, sizeof(ip_str));

    const char *nombreArchivo = (filename[0] == '/') ? filename + 1 : filename;

    char html[1024];
    snprintf(html, sizeof(html),
        "<!DOCTYPE html><html><head><meta charset='UTF-8'><title>ESP32 GPS Logger</title>"
        "<style>body{font-family:Arial;text-align:center;margin:50px;}h1{color:#333;} "
        "a.button{background:#4CAF50;color:white;padding:20px 40px;text-decoration:none;"
        "font-size:24px;border-radius:12px;display:inline-block;margin:20px;}</style></head>"
        "<body><h1>GPS Logger</h1><p>Archivo listo para descargar:</p>"
        "<a href='/download' class='button' download='%s'>Descargar %s</a>"
        "<hr><p>IP: %s</p><p>Se apagará en 5 min sin uso.</p></body></html>",
        nombreArchivo, nombreArchivo, ip_str);

    httpd_resp_set_type(req, "text/html");
    return httpd_resp_send(req, html, HTTPD_RESP_USE_STRLEN);
}

static esp_err_t download_get_handler(httpd_req_t *req)
{
    wifiLastActivity = xTaskGetTickCount();

    struct stat st;
    if (stat(filename, &st) != 0) {
        httpd_resp_send_404(req);
        return ESP_FAIL;
    }

    FILE *file = fopen(filename, "r");
    if (!file) {
        httpd_resp_send_404(req);
        return ESP_FAIL;
    }

    const char *nombreArchivo = (filename[0] == '/') ? filename + 1 : filename;
    char disposition[128];
    snprintf(disposition, sizeof(disposition),
             "attachment; filename=\"%s\"", nombreArchivo);

    httpd_resp_set_type(req, "application/gpx+xml");
    httpd_resp_set_hdr(req, "Content-Disposition", disposition);
    httpd_resp_send_file(req, file, st.st_size);

    fclose(file);
    return ESP_OK;
}

static const httpd_uri_t root_uri = {
    .uri       = "/",
    .method    = HTTP_GET,
    .handler   = root_get_handler,
    .user_ctx  = NULL
};

static const httpd_uri_t download_uri = {
    .uri       = "/download",
    .method    = HTTP_GET,
    .handler   = download_get_handler,
    .user_ctx  = NULL
};

static esp_err_t iniciar_servidor_http(void)
{
    httpd_config_t config = HTTPD_DEFAULT_CONFIG();
    if (httpd_start(&http_server, &config) != ESP_OK) {
        return ESP_FAIL;
    }

    httpd_register_uri_handler(http_server, &root_uri);
    httpd_register_uri_handler(http_server, &download_uri);
    return ESP_OK;
}