/**
 * Copyright (c) 2024 Raspberry Pi (Trading) Ltd.
 *
 * SPDX-License-Identifier: BSD-3-Clause
 */

#include <stdlib.h>
#include <tusb.h>
#include <bsp/board.h>
#include <pico/stdio.h>
#include <pico/stdlib.h>

#define LED_BLINK_DELAY_MS 1000

int main(void)
{
    // Initialize TinyUSB stack
    board_init();
    tusb_init();

    // let pico sdk use the first cdc interface for std io
    stdio_init_all();

    uint32_t start_ms = 0;
    bool led_state = false;

    // main run loop
    while(true)
    {
        // TinyUSB device task | must be called regurlarly
        tud_task();

        if(board_millis() - start_ms > LED_BLINK_DELAY_MS)
        {
            board_led_write(led_state);
            led_state = ! led_state;
            start_ms += LED_BLINK_DELAY_MS;

            if(tud_cdc_n_connected(0))
            {
                printf("Connected to CDC 0\n");
            }

            if(tud_cdc_n_connected(1))
            {
                printf("Connected to CDC 1\n");
            }
        }
    }
}

// callback when data is received on a CDC interface
void tud_cdc_rx_cb(uint8_t itf)
{
    // allocate buffer for the data in the stack
    uint8_t buf[CFG_TUD_CDC_RX_BUFSIZE];

    printf("RX CDC %d\n", itf);

    // read the available data 
    // | IMPORTANT: also do this for CDC0 because otherwise
    // | you won't be able to print anymore to CDC0
    // | next time this function is called
    uint32_t count = tud_cdc_n_read(itf, buf, sizeof(buf));

    // check if the data was received on the second cdc interface
    if (itf == 1) {
        // process the received data
        buf[count] = 0; // null-terminate the string
        // now echo data back to the console on CDC 0
        printf("Received on CDC 1: %s\n", buf);

        // and echo back OK on CDC 1
        tud_cdc_n_write(itf, (uint8_t const *) "OK\r\n", 4);
        tud_cdc_n_write_flush(itf);
    }
}