/*
 * noise.c -- USB Hardware TRNG Stream module
 *
 * SPDX-License-Identifier: GPL-2.0-or-later
 *
 * True random number generator.  Generates true random 32-byte entropy
 *       blocks via getrandom(GRND_RANDOM) and pipes them to the host
 *       over CDC ACM serial (/dev/ttyGS0) at 100Hz.
 */
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <string.h>
#include <sys/random.h>
#include <linux/input.h>
#include "h2_ui.h"
#include "log_manager.h"

int main(void) {
    init_h2_graphics_runtime("USB TRNG HARDWARE PIPE");
    LOG_INF("noise module started");

    lv_obj_t *scr = lv_scr_act();

    lv_obj_t *title = lv_label_create(scr);
    lv_label_set_text(title, "USB HARDWARE TRNG STREAM");
    lv_obj_align(title, LV_ALIGN_TOP_MID, 0, 10);
    lv_obj_set_style_text_color(title, COLOR_PRIMARY, LV_PART_MAIN);

    lv_obj_t *status = lv_label_create(scr);
    lv_label_set_text(status, "Piping true entropy to host CDC serial...\nNode: /dev/ttyGS0");
    lv_obj_align(status, LV_ALIGN_CENTER, 0, 0);

    int serial_fd = open("/dev/ttyGS0", O_WRONLY | O_NOCTTY);
    if (serial_fd < 0) LOG_WRN("cannot open /dev/ttyGS0");

    int input_fd = open("/dev/input/event0", O_RDONLY | O_NONBLOCK);
    struct input_event ev;
    uint8_t entropy_block[32];

    while (1) {
        lv_timer_handler();
        if (getrandom(entropy_block, sizeof(entropy_block), GRND_RANDOM) == sizeof(entropy_block)) {
            if (serial_fd != -1) (void)write(serial_fd, entropy_block, sizeof(entropy_block));
        }
        if (input_fd >= 0 && read(input_fd, &ev, sizeof(struct input_event)) > 0) {
            if (ev.type == EV_KEY && ev.code == H2_KEY_BACK && ev.value == 1) break;
        }
        usleep(10000);
    }
    if (serial_fd != -1) close(serial_fd);
    if (input_fd >= 0) close(input_fd);
    LOG_INF("noise module exited");
    return 0;
}