#include <LiquidCrystal_I2C.h>

LiquidCrystal_I2C lcd(0x27, 16, 2);

int etape = 0; // etape actuelle
int points[4] = {0, 0, 0, 0}; // les points
float moyenne_points[2] = {0, 0}; // la moyenne des points

void setup() {
  Serial.begin(9600);
  lcd.init();
  lcd.backlight(); 
  Serial.println("--------------"); // juste pour afficher le seral monitor
}

void loop() {
  if (etape == 0) { // premiere etape donc x1
    lcd.setCursor(0, 0);
    lcd.print("Entrer x1:");
    if (Serial.available()) {
      String inputString = ""; // clear la valeur pour quand le void loop recommence
      while (Serial.available()) {
        char inputChar = Serial.read();
        if (inputChar == '\n') { // verifie si la valeur n est que un saut à la ligne
          break; // si oui, le void loop recommencera car aucune valeur ajouté dans inputString
        }
        inputString += inputChar;
      }

      if (inputString.length() > 0) {
        int inputValue = inputString.toInt(); // convertie en int
        points[0] = inputValue; // attribue la valeur au point x1
        lcd.clear();
        lcd.setCursor(0, 0);
        lcd.print("x1: ");
        lcd.print(points[0]); // affiche aussi la valeur a l ecran
        etape++; // passe a l etape suivante
        Serial.println(inputValue);
        delay(500);
      }
    }
  } else if (etape == 1) { // deuxieme etape donc y1
    lcd.setCursor(0, 0);
    lcd.print("Entrer y1:");
    if (Serial.available()) {
      String inputString = "";
      while (Serial.available()) {
        char inputChar = Serial.read();
        if (inputChar == '\n') {
          break;
        }
        inputString += inputChar;
      }

      if (inputString.length() > 0) {
        int inputValue = inputString.toInt();
        points[1] = inputValue;
        lcd.clear();
        lcd.setCursor(0, 0);
        lcd.print("y1: ");
        lcd.print(points[1]);
        etape++;
        Serial.println(inputValue);
        delay(500);
      }
    }
  } else if (etape == 2) { // troisieme etape donc x2
    lcd.setCursor(0, 0);
    lcd.print("Entrer x2:");
    if (Serial.available()) {
      String inputString = "";
      while (Serial.available()) {
        char inputChar = Serial.read();
        if (inputChar == '\n') {
          break;
        }
        inputString += inputChar;
      }

      if (inputString.length() > 0) {
        int inputValue = inputString.toInt();
        points[2] = inputValue;
        lcd.clear();
        lcd.setCursor(0, 0);
        lcd.print("x2: ");
        lcd.print(points[2]);
        etape++;
        Serial.println(inputValue);
        delay(500);
      }
    }
  } else if (etape == 3) { // quatrieme etape donc y2
    lcd.setCursor(0, 0);
    lcd.print("Entrer y2:");
    if (Serial.available()) {
      String inputString = "";
      while (Serial.available()) {
        char inputChar = Serial.read();
        if (inputChar == '\n') {
          break;
        }
        inputString += inputChar;
      }

      if (inputString.length() > 0) {
        int inputValue = inputString.toInt();
        points[3] = inputValue;
        lcd.clear();
        lcd.setCursor(0, 0);
        lcd.print("x2: ");
        lcd.print(points[3]);
        etape++;
        Serial.println(inputValue);
        delay(500);
      }
    }
  } else if (etape == 4) { // cinquieme etape donc la moyenne
    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print("p1(");
    lcd.print(points[0]); // x1
    lcd.print(",");
    lcd.print(points[1]); // y1
    
    lcd.print(") p2(");
    lcd.print(points[2]); // x2
    lcd.print(",");
    lcd.print(points[3]); // y2
    lcd.print(")");

    // calcule le point moyenne
    moyenne_points[0] = (points[0] + points[2]) / 2.0;
    moyenne_points[1] = (points[1] + points[3]) / 2.0;

    delay(1000);

    lcd.setCursor(0, 1);
    lcd.print("pM(");
    lcd.print(moyenne_points[0]); // x3
    lcd.print(",");
    lcd.print(moyenne_points[1]); // y3
    lcd.print(")");

    delay(20000);
    lcd.clear();
    etape = 0;  // reset les etapes - recommence du debut
  }
}