/*
 *  This creates sound tones by outputting a square wave on a DAC pin. The
 *  volume of the tone is the level of the DAC pin.
 *
 *  The square wave is created by a timer. The timer runs at 2x the freq, because
 *  it needs to transition high and then low.
 *
 *
 */
#ifndef SOUND_H
  #define SOUND_H

#include "esp32-hal-timer.h";

#define ESP32_F_CPU         1000000  // the speed of the processor
#define AUDIO_INTERRUPT_PRESCALER   80
#define SOUND_TIMER_NO 0
//#define AUDIO_PIN 25
#define MIN_FREQ 20
#define MAX_FREQ 16000

hw_timer_t * sndTimer = NULL;

bool sound_on = true;
bool sound_wave_high = true;  // this toggles to create the high/low transitions of the wave
uint8_t sound_volume = 0;

void sound_init(int pin);
bool sound(uint16_t freq, uint8_t volume);
void soundOff();

int dac_pin;



void IRAM_ATTR onSoundTimer()
{
    if (sound_on) {
        //dacWrite(dac_pin, (sound_wave_high?sound_volume:0));
        sound_wave_high = ! sound_wave_high;
    }
    //else
    //  dacWrite(dac_pin, 0);
}

void sound_init(int pin){  // pin must be a DAC pin number !! (typically 25 or 26)
    return;
    dac_pin = pin;
    sound_on = false;
    //pinMode(dac_pin, OUTPUT);
    sound_volume = 0;

#ifdef OLD_CODE
    sndTimer = timerBegin(SOUND_TIMER_NO, AUDIO_INTERRUPT_PRESCALER, true);
    timerAttachInterrupt(sndTimer, &onSoundTimer, true);
    timerAlarmWrite(sndTimer, ESP32_F_CPU/AUDIO_INTERRUPT_PRESCALER/MIN_FREQ, true); // lower timer freq
    timerAlarmEnable(sndTimer);
#else
    //void RH_INTERRUPT_ATTR esp32_timer_interrupt_handler(); // Forward declaration
    sndTimer = timerBegin(ESP32_F_CPU);
    timerAttachInterrupt(sndTimer, &onSoundTimer);
    timerAlarm(sndTimer, ESP32_F_CPU/AUDIO_INTERRUPT_PRESCALER/MIN_FREQ, true, 0);
#endif

}

void sound_pause() // this prevents the interrupt from firing ... use during eeprom write
{
    if (sndTimer != NULL)
        timerStop(sndTimer);
}

void sound_resume() // resume from pause ... after eeprom write
{
    if (sndTimer != NULL)
        timerRestart(sndTimer);
}

bool sound(uint16_t freq, uint8_t volume){
    return true;
    if (volume == 0) {
        soundOff();
        return false;
    }
    if (freq < MIN_FREQ || freq > MAX_FREQ) {
        return false;
    }
    sound_on = true;
    sound_volume = volume;
  //timerAlarmWrite(sndTimer, ESP32_F_CPU/AUDIO_INTERRUPT_PRESCALER/(freq * 2), true);
    timerAlarm(sndTimer, ESP32_F_CPU/AUDIO_INTERRUPT_PRESCALER/(freq * 2), true, 0);
    return true;
}

void soundOff(){
    return;
    sound_on = false;
    sound_volume = 0;
    //timerAlarmWrite(sndTimer, ESP32_F_CPU/AUDIO_INTERRUPT_PRESCALER/(MIN_FREQ), true);  // lower timer freq
    timerAlarm(sndTimer, ESP32_F_CPU/AUDIO_INTERRUPT_PRESCALER/(MIN_FREQ), true, 0);
    //timerAlarm(hw_timer_t *timer, uint64_t alarm_value, bool autoreload, uint64_t reload_count);
}



#endif