#include <Arduino.h>

#include "generators.hpp"
#include "filters.hpp"

constexpr int DAC_PIN = A2;

constexpr uint16_t SAMPLING_RATE_HZ = 8000;

constexpr unsigned long SAMPLE_US = 1000000 / SAMPLING_RATE_HZ;

#ifndef LED_BUILTIN
    #define LED_BUILTIN PC13
#endif

unsigned long last_time_us = 0;

int16_t val;

bool sample_computed = false;

constexpr uint32_t hz_to_micros(uint32_t hz) {
    return 1000000 / hz;
}

void setup() {
    delay(3000);
}

void loop() {
    unsigned long time_us = micros();
    unsigned long delta = time_us - last_time_us;
    if (!sample_computed) {
        if (delta < SAMPLE_US)  {
            constexpr uint32_t period = hz_to_micros(412);
            val = sine<period, 512>(time_us % period);
            sample_computed = true;
        }
    }
    else {
        if (delta >= SAMPLE_US) {
            last_time_us = time_us;
            analogWrite(DAC_PIN, val);
            sample_computed = false;
        }
    }
    delayMicroseconds(1);
}