#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>

#define SCREEN_WIDTH 128 // OLED display width, in pixels
#define SCREEN_HEIGHT 64 // OLED display height, in pixels
#define OLED_RESET     -1 // Reset pin # (or -1 if sharing Arduino reset pin)
#define SCREEN_ADDRESS 0x3C // See datasheet for Address; 0x3D for 128x64, 0x3C for others

Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);

const int numSensors = 12; // Total number of sensors
const int sensorPins[numSensors] = {A0, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11}; // Sensor pins
double voltages[numSensors]; // To store voltage readings
const int Sensors_max = 2500; // Maximum value after mapping
const int offset = 20; // Correction offset

void setup() {
  // Initialize OLED display
  if(!display.begin(SSD1306_SWITCHCAPVCC, SCREEN_ADDRESS)) {
    Serial.println(F("SSD1306 allocation failed"));
    for(;;); // Don't proceed, loop forever
  }
  display.display();
  delay(2000); // Pause for 2 seconds
}

void loop() {
  readAndConvertVoltages();
  displayVoltagesOnOLED();
  delay(100); // Delay before the next loop iteration
}

void readAndConvertVoltages() {
  for (int i = 0; i < numSensors; i++) {
    int readValue = analogRead(sensorPins[i]);
    // Convert and map 0-1023 to 0-Sensors_max, then adjust with offset and convert to volts
    voltages[i] = (map(readValue, 0, 1023, 0, Sensors_max) + offset) / 100.0;
  }
}

void displayVoltagesOnOLED() {
  display.clearDisplay();
  display.setTextSize(1); // Normal 1:1 pixel scale
  display.setTextColor(SSD1306_WHITE); // Draw white text
  
  int colWidth = SCREEN_WIDTH / 2; // Two columns
  int rowHeight = SCREEN_HEIGHT / 6; // Six rows
  
  for (int i = 0; i < numSensors; i++) {
    int col = i / 6; // 0 for the first six sensors, 1 for the second set of six
    int row = i % 6; // Row number within each column
    int x = col * colWidth;
    int y = row * rowHeight;
    
    display.setCursor(x, y);
    // Using 'A' + i to get the ASCII character after 'A' for each sensor
    display.print(char('A' + i));
    display.print(": ");
    display.print(voltages[i], 2);
    display.print("V "); // Added space and unit
  }
  
  display.display(); // Actually draw everything to the screen
}