Remote Aroma Diffuser Timer

#include <Arduino.h>
#include <IRremote.hpp>


// Hoisted type definitions
struct Button {
  uint8_t pin;
  bool stableState;
  bool lastReading;
  uint32_t changedAt;
};


// Forward declarations
void applyOutput();
void printStatus();
void turnOff();
void togglePower();
void startTimer(uint32_t durationMs);
bool buttonPressed(Button &button, uint32_t now);
void handleCommand(uint16_t command);

constexpr uint8_t POWER_BUTTON_PIN = 32;
constexpr uint8_t TIMER_30_BUTTON_PIN = 33;
constexpr uint8_t TIMER_60_BUTTON_PIN = 26;
constexpr uint8_t TIMER_120_BUTTON_PIN = 14;
constexpr uint8_t IR_RECEIVE_PIN = 27;
constexpr uint8_t MIST_GATE_PIN = 25;

constexpr uint32_t MINUTE_MS = 60000UL;
constexpr uint32_t TIMER_30_MS = 30UL * MINUTE_MS;
constexpr uint32_t TIMER_60_MS = 60UL * MINUTE_MS;
constexpr uint32_t TIMER_120_MS = 120UL * MINUTE_MS;
constexpr uint32_t DEBOUNCE_MS = 35;

// Set these after observing your remote's printed command values in the Deploy log.
// The default 0xFFFFFFFF values deliberately match no normal IR command.
constexpr uint16_t REMOTE_POWER_COMMAND = 0xFFFF;
constexpr uint16_t REMOTE_30_COMMAND = 0xFFFF;
constexpr uint16_t REMOTE_60_COMMAND = 0xFFFF;
constexpr uint16_t REMOTE_120_COMMAND = 0xFFFF;



Button buttons[] = {
  {POWER_BUTTON_PIN, HIGH, HIGH, 0},
  {TIMER_30_BUTTON_PIN, HIGH, HIGH, 0},
  {TIMER_60_BUTTON_PIN, HIGH, HIGH, 0},
  {TIMER_120_BUTTON_PIN, HIGH, HIGH, 0}
};

bool diffuserOn = false;
bool timerActive = false;
uint32_t offAt = 0;

void applyOutput() {
  digitalWrite(MIST_GATE_PIN, diffuserOn ? HIGH : LOW);
}

void printStatus() {
  if (!diffuserOn) {
    Serial.println("Diffuser: OFF");
  } else if (timerActive) {
    const int32_t remaining = static_cast<int32_t>(offAt - millis());
    Serial.printf("Diffuser: ON, timer remaining: %ld seconds\n", max(0L, static_cast<long>(remaining / 1000)));
  } else {
    Serial.println("Diffuser: ON continuously");
  }
}

void turnOff() {
  diffuserOn = false;
  timerActive = false;
  applyOutput();
  printStatus();
}

void togglePower() {
  diffuserOn = !diffuserOn;
  timerActive = false;
  applyOutput();
  printStatus();
}

void startTimer(uint32_t durationMs) {
  diffuserOn = true;
  timerActive = true;
  offAt = millis() + durationMs;
  applyOutput();
  printStatus();
}

bool buttonPressed(Button &button, uint32_t now) {
  const bool reading = digitalRead(button.pin);
  if (reading != button.lastReading) {
    button.lastReading = reading;
    button.changedAt = now;
  }
  if ((now - button.changedAt) >= DEBOUNCE_MS && reading != button.stableState) {
    button.stableState = reading;
    return button.stableState == LOW;
  }
  return false;
}

void handleCommand(uint16_t command) {
  if (command == REMOTE_POWER_COMMAND) {
    togglePower();
  } else if (command == REMOTE_30_COMMAND) {
    startTimer(TIMER_30_MS);
  } else if (command == REMOTE_60_COMMAND) {
    startTimer(TIMER_60_MS);
  } else if (command == REMOTE_120_COMMAND) {
    startTimer(TIMER_120_MS);
  }
}

void setup() {
  Serial.begin(115200);
  pinMode(MIST_GATE_PIN, OUTPUT);
  digitalWrite(MIST_GATE_PIN, LOW);
  for (Button &button : buttons) {
    pinMode(button.pin, INPUT_PULLUP);
  }
  IrReceiver.begin(IR_RECEIVE_PIN, DISABLE_LED_FEEDBACK);
  Serial.println("Aroma diffuser controller ready.");
  Serial.println("Press each IR remote button once; record the printed Command value and place it in the matching REMOTE_*_COMMAND constant.");
  printStatus();
}

void loop() {
  const uint32_t now = millis();

  if (buttonPressed(buttons[0], now)) togglePower();
  if (buttonPressed(buttons[1], now)) startTimer(TIMER_30_MS);
  if (buttonPressed(buttons[2], now)) startTimer(TIMER_60_MS);
  if (buttonPressed(buttons[3], now)) startTimer(TIMER_120_MS);

  if (IrReceiver.decode()) {
    if (IrReceiver.decodedIRData.flags & IRDATA_FLAGS_IS_REPEAT) {
      IrReceiver.resume();
      return;
    }
    const uint16_t command = IrReceiver.decodedIRData.command;
    Serial.printf("IR protocol=%d address=0x%X command=0x%X\n", IrReceiver.decodedIRData.protocol, IrReceiver.decodedIRData.address, command);
    handleCommand(command);
    IrReceiver.resume();
  }

  if (timerActive && static_cast<int32_t>(now - offAt) >= 0) {
    turnOff();
  }
}