/*
   save an unsigned integer in Preferences instead of a String/string
   de: uint statt string speichern und ausgeben.
   
   based on https://forum.arduino.cc/t/preferences-string-array-lesen-und-speichern/1444522/8 by Kai-R
   2026-05-17 by noiasca https://forum.arduino.cc/t/preferences-string-array-lesen-und-speichern/1444522/11 

   Code in forum

   to be deleted here 2026-11
*/

#include <Preferences.h>
#include <iostream>
#include "button.h"   // simplified class to debounce a button (see separate tab)

Preferences prefs;
constexpr unsigned maxBufferLen {10};
char buffer[maxBufferLen];

Button btnIncreaseVolume(18);

uint16_t volume;                 // @todo tbd if needed as global, value is anyway in the preferences.

// sends the volume to the destination
void volumeSend() {
  std::cout << std::endl;        // debug only (otherwise you don't see the last line here in the demo imidiately)

  sprintf(buffer, "VOL:%02d;", volume);
  std::cout << buffer;           // output to destination - this MVP just uses the Serial

  std::cout << std::endl;        // debug only (otherwise you don't see the last line here in the demo imidiately)
}

// increase volume, persist to preferences and send to destination
void volumeIncrease() {
  std::cout << std::endl << "vol inc" << std::endl;        // debug only
  volume++;
  if (volume > 99) volume = 99;
  prefs.putUInt("volume", volume);
  volumeSend();
}

// timer to check if volume needs to be sent to destination
void volumeTimer(uint32_t currentMillis = millis()) {
  static uint32_t previousMillis = 0;
  if (currentMillis - previousMillis > 5 * 1000UL) {
    previousMillis = currentMillis;
    volumeSend();
  }
}

void setup() {
  Serial.begin(115200);
  prefs.begin("Prefs", false);
  btnIncreaseVolume.begin();

  // Wenn Key noch nicht vorhanden ist, lege ihn an
  if (!prefs.isKey("volume")) {
    std::cout << "Create key volume" << std::endl;
    prefs.putUInt("volume", 0);
  }

  // Lese Daten aus Preferences
  prefs.getUInt("volume", volume);

  std::cout << "Current volume as number: " << volume << std::endl;
}

void loop() {
  if (btnIncreaseVolume.wasPressed()) volumeIncrease();
  volumeTimer();
}
//