// main.cpp

#include "mbed.h"

#define MAXIMUM_BUFFER_SIZE 32

DigitalOut led1(LED1);
static BufferedSerial serial_port(USBTX, USBRX);

class Led {
private:
    Ticker ticker;
    bool ledState;

public:
    Led() : ledState(false) {
        led1 = ledState;
    }

    void setBlinkPeriod(float period) {
        ticker.detach();
        ticker.attach(callback(this, &Led::tickerHandler), period / 2.0f);
    }

    void tickerHandler() {
        ledState = !ledState;
        led1 = ledState;
    }
};

int main()
{
    serial_port.set_baud(9600);
    serial_port.set_format(
        /* bits */ 8,
        /* parity */ BufferedSerial::None,
        /* stop bit */ 1
    );

    char buf[MAXIMUM_BUFFER_SIZE] = {0};
    Led ledController;
    ledController.setBlinkPeriod(1.0f);

    while (1) {
        if (uint32_t num = serial_port.read(buf, sizeof(buf))) {
            if (buf[0] >= '0' && buf[0] <= '9') {
                float period = buf[0] - '0';
                if (period > 0) {
                    ledController.setBlinkPeriod(period);
                } else {
                    ledController.setBlinkPeriod(0.1f);
                }
            }
            serial_port.write(buf, num);
        }
        ThisThread::sleep_for(100ms);
    }
}