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

#define SCREEN_WIDTH 128 // OLED display width
#define SCREEN_HEIGHT 64 // OLED display height
#define OLED_RESET    -1 // Reset pin (or -1 if sharing Arduino reset)
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);

// Pin definitions
#define ANALOG_PIN_1 A0 // Shared voltage for Pin 1
#define ANALOG_PIN_2 A1 // Shared voltage for Pin 2
#define LOW_LEVEL_PIN 6 // Digital pin for low-level input (Pin 5)

void setup() {
  // Initialize the OLED display
  if (!display.begin(SSD1306_PAGEADDR, 0x3C)) { // Address 0x3C for 128x64
    Serial.begin(9600); // For debugging (optional)
    Serial.println(F("SSD1306 allocation failed"));
    for (;;); // Halt program if initialization fails
  }

  // Set up pins
  pinMode(ANALOG_PIN_1, INPUT);
  pinMode(ANALOG_PIN_2, INPUT);
  pinMode(LOW_LEVEL_PIN, INPUT_PULLUP); // Low-level input with pull-up resistor

  display.clearDisplay();
  display.setTextColor(SSD1306_WHITE);

  // Call the loading screen
  loadingScreen();
}

void loop() {
  // Update the display with pin labels and values
  displayPins();
  delay(500); // Refresh every 500 ms
}

// Function to display a loading screen
void loadingScreen() {
  display.clearDisplay();
  display.setCursor((SCREEN_WIDTH - 60) / 2, SCREEN_HEIGHT / 2 - 8);
  display.print(F("Loading..."));

  // Draw a progress bar
  int barWidth = 100;
  int barHeight = 10;
  int barX = (SCREEN_WIDTH - barWidth) / 2;
  int barY = SCREEN_HEIGHT / 2 + 8;

  for (int i = 0; i <= barWidth; i++) {
    display.drawRect(barX, barY, barWidth, barHeight, SSD1306_WHITE); // Draw border
    display.fillRect(barX, barY, i, barHeight, SSD1306_WHITE);        // Fill progress
    display.display();
    delay(20);
  }

  delay(500);
}

// Function to display pin labels and values
void displayPins() {
  display.clearDisplay();

  // Top labels
  display.setCursor(0, 0);
  display.print(F("<-----  POWER"));
  display.setCursor(SCREEN_WIDTH - 36, 0);
  display.print(F("----->"));

  // Display pins for both sides
  for (int i = 1; i <= 5; i++) {
    displayPinInfo(i, 0, true);                          // Left side
    displayPinInfo(i, SCREEN_WIDTH - 51, false);         // Right side
  }

  display.display();
}

// Function to display a single pin's label and value
void displayPinInfo(int pinIndex, int x, bool isLeft) {
  int y = 10 + (pinIndex - 1) * 9; // Calculate vertical position
  float voltage;

  // Handle different pins
  switch (pinIndex) {
    case 1: // Pin 1 - Voltage from A0
      voltage = analogRead(ANALOG_PIN_1) * (5.0 / 1023.0);
      display.setCursor(x, y);
      display.print(pinIndex);
      display.print(F("-"));
      display.setCursor(x + 15, y);
      display.print(voltage * 5, 2); // Multiply by 5 if using a voltage divider for 24V
      display.print(F("V"));
      break;

    case 2: // Pin 2 - Voltage from A1
      voltage = analogRead(ANALOG_PIN_2) * (5.0 / 1023.0);
      display.setCursor(x, y);
      display.print(pinIndex);
      display.print(F("-"));
      display.setCursor(x + 15, y);
      display.print(voltage * 5, 2); // Multiply by 5 if using a voltage divider for 24V
      display.print(F("V"));
      break;

    case 3: // Pin 3 - GROUND
    case 4: // Pin 4 - GROUND
      display.setCursor(x, y);
      display.print(pinIndex);
      display.print(F("-"));
      display.setCursor(x + 15, y);
      display.print(F("GROUND"));
      break;

    case 5: // Pin 5 - Low-Level Input
      display.setCursor(x, y);
      display.print(pinIndex);
      display.print(F("-"));
      display.setCursor(x + 15, y);
      if (digitalRead(LOW_LEVEL_PIN) == LOW) {
        display.print(F("LOW"));
      } else {
        display.print(F("HIGH"));
      }
      break;
  }
}