#include <Arduino.h>
#include <LiquidCrystal_I2C.h>

#define LED 2
#define BUTTON_PIN 32
#define SLIDER_BPM 34
#define SLIDER_AMPLITUDE 35

LiquidCrystal_I2C lcd1(0x27, 20, 8);  // First LCD
LiquidCrystal_I2C lcd2(0x3F, 20, 8);  // Second LCD

hw_timer_t *My_timer = NULL;
volatile bool arythmiaMode = false;
volatile float adValue = -10;
volatile float bpm = 60;  // Default BPM
volatile float amplitude = 1.0;  // Full amplitude

volatile unsigned long startTime = 0;
const unsigned long runDuration = 30000;

byte waveform[5][8] = {  // Custom characters for waveform visualization
  {0,0,0,0,0,0,0,31},
  {0,0,0,0,0,0,31,31},
  {0,0,0,0,0,31,31,31},
  {0,0,0,0,31,31,31,31},
  {0,0,31,31,31,31,31,31}
};

void IRAM_ATTR onTimer() {
  static int vector = 0;
  if (millis() - startTime < runDuration) {
    float angle = (vector * PI / 180) * bpm / 60;
    adValue = sin(angle) * amplitude;
    if (++vector >= 360) vector = 0;
  } else {
    adValue = 0;
  }
}

void setup() {
  pinMode(LED, OUTPUT);
  pinMode(BUTTON_PIN, INPUT_PULLUP);
  pinMode(SLIDER_BPM, INPUT);
  pinMode(SLIDER_AMPLITUDE, INPUT);

  startTime = millis(); 

  My_timer = timerBegin(0, 80, true);
  timerAttachInterrupt(My_timer, &onTimer, true);
  timerAlarmWrite(My_timer, 1000000 / (bpm / 60), true);
  timerAlarmEnable(My_timer);

  Serial.begin(115200);

  lcd1.init(); lcd1.backlight();
  lcd2.init(); lcd2.backlight();

  for (int i = 0; i < 5; i++) {
    lcd1.createChar(i, waveform[i]);
    lcd2.createChar(i, waveform[i]);
  }
}

void loop() {
  if (digitalRead(BUTTON_PIN) == LOW) {
    arythmiaMode = !arythmiaMode;
    delay(500); // Debouncing
  }

  int newBpmReading = analogRead(SLIDER_BPM);
  bpm = map(newBpmReading, 0, 4095, 40, 240);

  int newAmplitudeReading = analogRead(SLIDER_AMPLITUDE);
  amplitude = map(newAmplitudeReading, 0, 4095, 10, 100) / 100.0;

  timerAlarmWrite(My_timer, 1000000 / (bpm / 60), true);

  static int pos = 0;  // Position tracking across both LCDs
  if (adValue != -10) {
    int waveHeight = map(adValue * 100, -100, 100, 0, 4);
    if (pos < 20) {
      lcd1.setCursor(pos, 4);
      lcd1.write(waveHeight);
    } else {
      lcd2.setCursor(pos - 20, 4);
      lcd2.write(waveHeight);
    }
    pos = (pos + 1) % 40; // Wrap around after 40 (20 per LCD)
    adValue = -10;
  }
}