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

#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64
#define OLED_RESET -1
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);

const int BUTTON_PIN = 12;

const int C1_OUTPUT = 2;
const int C2_OUTPUT = 3;
const int C3_OUTPUT = 4;

const int RELAY_PIN = 11;



const int KNOWN_RESISTOR_1 = 99; // Resistance of the known resistor R1 in ohms
const int KNOWN_RESISTOR_2 = 99; // Resistance of the known resistor R2 in ohms
const int KNOWN_RESISTOR_3 = 99; // Resistance of the known resistor R3 in ohms


enum TestMode { CONTINUITY, RESISTANCE };
TestMode currentMode = CONTINUITY;

unsigned long lastPressTime = 100;
bool buttonPressed = false;

// Function declarations
void testCONTINUITY();
void testRESISTANCE();

void setup() {
  pinMode(C1_OUTPUT, OUTPUT);
  pinMode(C2_OUTPUT, OUTPUT);
  pinMode(C3_OUTPUT, OUTPUT);
  pinMode(RELAY_PIN, OUTPUT);
  pinMode(BUTTON_PIN, INPUT_PULLUP);

  display.begin(SSD1306_SWITCHCAPVCC, 0x3C);
  display.clearDisplay();
  display.setTextSize(2);
  display.setTextColor(SSD1306_WHITE);
  display.setCursor(0, 30);
  display.print("Loading");
  display.display();
  delay(500);
  display.setCursor(0, 30);
  display.print("Loading.");
  display.display();
  delay(500);
  display.setCursor(0, 30);
  display.print("Loading..");
  display.display();
  delay(500);
  display.setCursor(0, 30);
  display.print("Loading...");
  display.display();
  delay(500);

  digitalWrite(RELAY_PIN, HIGH);
}

void loop() {
  if (digitalRead(BUTTON_PIN) == LOW && !buttonPressed) {
    lastPressTime = millis();
    buttonPressed = true;
  }

  if (digitalRead(BUTTON_PIN) == HIGH && buttonPressed) {
    unsigned long pressDuration = millis() - lastPressTime;
    buttonPressed = false;

    if (pressDuration < 500) {
      currentMode = (currentMode == CONTINUITY) ? RESISTANCE : CONTINUITY;
    }
  }

  digitalWrite(RELAY_PIN, (currentMode == CONTINUITY) ? LOW : HIGH);

  if (currentMode == CONTINUITY) {
    testCONTINUITY();
  } else {
    testRESISTANCE();
  }

  delay(20);
}

void testCONTINUITY() {
  // Continuity1 Test
  digitalWrite(C1_OUTPUT, HIGH); //make one end of XLR  float to VCC+5
  digitalWrite(C2_OUTPUT, LOW);//make one end of XLR  short to GND
  digitalWrite(C3_OUTPUT, LOW); //make one end of XLR  short to GND
  delay(1000);
  int continuity1_C1 = digitalRead(A0);
  int continuity2_C1 = digitalRead(A1);
  int continuity3_C1 = digitalRead(A2);

  digitalWrite(C1_OUTPUT, LOW); //make one end of XLR  short to GND
  digitalWrite(C2_OUTPUT, HIGH);//make one end of XLR  loat to VCC+5
  digitalWrite(C3_OUTPUT, LOW); //make one end of XLR  short to GND
  delay(1000);
  int continuity1_C2 = digitalRead(A0);
  int continuity2_C2 = digitalRead(A1);
  int continuity3_C2 = digitalRead(A2);

  digitalWrite(C1_OUTPUT, LOW); //make one end of XLR  short to GND
  digitalWrite(C2_OUTPUT, LOW);//make one end of XLR  short to GND
  digitalWrite(C3_OUTPUT, HIGH); //make one end of XLR  float to VCC+5
  delay(1000);
  int continuity1_C3 = digitalRead(A0);
  int continuity2_C3 = digitalRead(A1);
  int continuity3_C3 = digitalRead(A2);

 
 

  display.clearDisplay();
  display.setCursor(0, 0);
  if (continuity1_C1 == HIGH && continuity1_C2 == LOW && continuity1_C3 == LOW) {
    displayContinuityResult("C1", "OK");
  } else {
    displayContinuityResult("C1", "BAD");
  }
  delay(20);
  display.setCursor(0, 20);
  if (continuity2_C1 == LOW && continuity2_C2 == HIGH && continuity2_C3 == LOW) {
    displayContinuityResult("C2", "OK");
  } else {
    displayContinuityResult("C2", "BAD");
  }

  delay(20);
  display.setCursor(0, 40);
  if (continuity3_C1 == LOW && continuity3_C2 == LOW && continuity3_C3 == HIGH) {
    displayContinuityResult("C3", "OK");
  } else {
    displayContinuityResult("C3", "BAD");
  }
  display.display();
  delay(20);
}

void testRESISTANCE() {

  digitalWrite(C1_OUTPUT, LOW);//make one end of XLR  short to GND
  digitalWrite(C2_OUTPUT, LOW);//make one end of XLR  short to GND
  digitalWrite(C3_OUTPUT, LOW);//make one end of XLR  short to GND
  delay(200);
  float resistance_1 = measureResistance(A0, KNOWN_RESISTOR_1);
  float resistance_2 = measureResistance(A1, KNOWN_RESISTOR_2);
  float resistance_3 = measureResistance(A2, KNOWN_RESISTOR_3);

  display.clearDisplay();
  display.setCursor(0, 0);
  display.print("R1: ");
  if (resistance_1 > 300) {
    display.print("BAD");
  } else {
    display.print(resistance_1);
  }
  display.print(" ");

  display.setCursor(0, 20);
  display.print("R2: ");
  if (resistance_2 > 300) {
    display.print("BAD");
  } else {
    display.print(resistance_2);
  }
  display.print(" ");

  display.setCursor(0, 40);
  display.print("R3: ");
  if (resistance_3 > 300) {
    display.print("BAD");
  } else {
    display.print(resistance_3);
  }
  display.print(" ");

  display.display();
}

float measureResistance(int pin, int knownResistor) {
  int resistanceValue = analogRead(pin);
  float voltage = (resistanceValue / 1023.0) * 5.0;
  float resistance = (voltage * knownResistor) / (5.0 - voltage);
  return resistance;
}

void displayContinuityResult(String circuit, String result) {
  display.print(circuit + ": ");
  display.println(result);
}