/*   */


#include <LiquidCrystal_I2C.h>
#include "TimerOne.h"

LiquidCrystal_I2C lcd(0x27, 20, 4);

// flasher associated variables
int val = 1; // flasher

// potentiometer associated variables
int sensorPin = A0; // input analog pin for potentiometer
int sensorValue = 0; // potentiometer analog value
unsigned int voltageValue = 0; // potentiometer value scaled to 0-1000
int oldValue = 0;

// pwm associated variables and objects
const byte pwmPin = 10;  // output pin for PWM
TimerOne Timer1; // instanciation de la classe, i.e. création d'un objet TimerOne

// serial input associated variables
int incomingByte = 0; // for incoming serial data

// pwm sampling associated variables
unsigned long periode = 0; // period in ms
unsigned long temps_on = 0; // time signal is on in ms
bool pinState = LOW; // pwm sampling pin state
bool lastPinState = LOW; 
int pinCounter = 0; // counter to bypass first cycles 
unsigned long tempsRising0 = 0; // recorded time for rising edge
unsigned long tempsRising1 = 0; // recorded time for rising edge
unsigned long tempsFalling = 0; // recordes time for falling edge
bool toto;
unsigned long II = 0;

bool edgePin(bool value) {
static bool previousValue;
  // bool result = (value  && !previousValue);
  bool result = (value  ^ previousValue);
  previousValue = value;
  return result;
}


void setup() {
  // write to console
  Serial.begin(115200);
  Serial.println("Hello Arduino\n");

  // write to ldc
  lcd.init();
  lcd.backlight();
  lcd.clear();
  lcd.setCursor(0,0);
  lcd.print("periode");
  lcd.setCursor(0,1);
  lcd.print("duty");

  // define pin modes
  pinMode(7, OUTPUT); // alternate pwm output
  pinMode(8, INPUT);  // pwm sampling

  // pwm initialization
  Timer1.initialize(1000000);  // 50000 μs = 20 Hz - modifié pour 1 seconde
  Timer1.pwm(pwmPin, 511);   // 0-1023 = 0-100% duty

}

void loop() {
  // delay(20);

  // read the potentiometer
  sensorValue = analogRead(sensorPin);
  // changer le duty cycle du PWM sur la pin 9
  if (sensorValue < 102) {sensorValue = 102;}
  if (sensorValue > 921) {sensorValue = 921;}

  if (oldValue != sensorValue ) {
    Timer1.pwm(pwmPin, sensorValue);
  }
  oldValue = sensorValue; // store previous value

  /* 
  // alternate pwm output based on potentiometer voltage
  voltageValue = map(sensorValue,0,1023,0,1000); // scaling
  int tempsON = 1000*voltageValue/100;
  int tempsOFF = 1000.0 - tempsON;
  digitalWrite(7,HIGH);
  delay(tempsON);
  digitalWrite(7,LOW);
  delay(tempsOFF);
  */

  /*
  // flasher
  val = val * -1;
  if (val == 1) {digitalWrite(7,HIGH);} else {digitalWrite(7,LOW);}
  */
  
  /*
  // reading from the computer console
  if (Serial.available() > 0) {
      // read the incoming byte
      incomingByte = Serial.read();
      // Serial.println(incomingByte);
      Serial.write(incomingByte);

    }
  */

  // reading from the computer console
  if (Serial.available() > 0) {
    // read the incoming string
    String teststr = Serial.readString();
    // Serial.println(incomingByte);
    Serial.print(teststr);
   } 

  // pwm sampling

  pinState = digitalRead(8); // pin state

  if (pinState != lastPinState) { // change of state
    if (pinState == HIGH) { // rising edge
      tempsRising1 = tempsRising0; // store time of rising edge
      tempsRising0 = millis();
      if (pinCounter++ >= 3) {pinCounter = 3; // flag for stable pwn signal after 3 cycles
      } 
    } 
    else if (pinState == LOW) { // falling edge
      tempsFalling = millis(); // store time of falling edge
      if (pinCounter == 3) {
        periode = tempsRising0 - tempsRising1;
        temps_on = tempsFalling - tempsRising0;
        lcd.setCursor(10,0);
        lcd.print(periode);
        lcd.print(" ");
        lcd.setCursor(5,1);
        lcd.print(temps_on);
        lcd.print(" "); // required to erase the characters at the right end 
      }
    }
  }

  lastPinState = pinState;

 // cannot call the edge function more than one time in a cycle
  if (edgePin(pinState)) {
    if (pinState) {
      Serial.println("rising");
    }
    else {
      Serial.println("falling");
    }
  }  

}