///////////////////////////////////// liaison ceramic ///////////////////////////////////////
// the following code makes talk the LDR (light dependent resistor) to the led

// hier all the vavriable are declared

// variables for the sensor circuit
int analogPin=1;  // sets the analog pin to communicate to the LDR 
int val; // stores the read values

// variable for the led circuit
int ledpin = 10;  // sets the pin 10 to communicate to the led
int key;  // stores the analog data
int key1;  // stores the analog data after from 'key'
int i = 0;  // store the values to meke the led blink
int j = 0;  // store the values to make the led turn on
int k= 255;
long previousMillis = 0;  // stores last time LED was updated
long interval = 40; 

boolean onState = false;  // asks if the LDR state is on

// this function will run just once, hier all the general setup are written
void setup (){
  Serial.begin(9600);  // opens serial port, sets data rate to 9600 bps
  Serial.println ('b');  // prints the data to the serial port
  pinMode(ledpin, OUTPUT);  // configures the pin 10 to behave as an output
}

// this one runs consecutively
void loop(){
  val = analogRead(analogPin);  // 'val' stores the light data coming from analog pin

  if (val>900){  // if the light intensity is under 900
    if (onState == false){  // is the LDR state is off
      Serial.print('b');  // the letter 'b' is wirtten to the console
      onState= true;  // and the LDR state will turn on
      delay(2000); // with a 2 seconds delay 
    }
  } else {  // otherwise
    if (onState == true){  // if the LDR state is off
      Serial.print('t');  // the letter 't' is printed to the console
      onState = false;  // and the LDR state will turned on  
      delay(2000);  // with a 2 seconds delay
    }
  }

  if (Serial.available()){  // if the number of bytes are available for reading over the serial port
    key = Serial.read();  // the value 'key' stores the serial data when they come
    if (key == 't'){  // if the coming data are equal to 't', so the light is turned on 
      fadeToOn(ledpin);  // the led fades on through the function fadeToOn ()
      key1=key;  // and those values are stored into 'key1'
    }
    if (key == 'b'){  // if the coming data are equal to 'b', the light is tunres off
      turnOff(ledpin);  // the led turns off through the turnOff () function
      key1=key;  // and 'key1' strors the data
    }
  }   
}

////////////// function: fade to on ///////////////
void fadeToOn(int ledpin){  // the led connected to pin 10 fades on through this function
  while(j<255){  // while the value is less than 255
    if ((millis() - previousMillis) > interval) {
      analogWrite(ledpin, j);  // sets the value (range from 0 to 255)
      j+=5;  // and increases to 5
      previousMillis = millis();  // the variable previousMillis stores the values of the millis () function
    }
  }
  if (j=255){  // if it is equal to 255
    analogWrite(ledpin,255);  //  the ledpin will sets to 255
  }
  j=0;  // and the 'j' will empty
}
 
////////////// function: blink with fade ///////////////
void blink(int ledpin){  // sets the led pin 10 to be used to make the led blink
  while(i<25){  // while the variable 'i' is less than 25 
    if ((millis() - previousMillis) > interval) {
      analogWrite(ledpin, i);  // sets the value (range from 0 to 255)
      i+=5;  // the value increases of 5
      previousMillis = millis();  // the variable previousMillis stores the values of the millis () function
    }  
  }

  while(i>=25 && i<255){  // while the value is greater than 25 and less than 255
    if ((millis() - previousMillis) > interval) {
      analogWrite(ledpin, i);  // sets the value (range from 0 to 255)
      i+=5;  // the value increases of 5
      previousMillis = millis();  // the variable previousMillis stores the values of the millis () function
    }  
  }
  i=25;  // assigns value 25

  while(k>25){  // while the variable 'k' is greater than 25
    if ((millis() - previousMillis) > interval) {
      analogWrite(ledpin, k);  // sets the value (range from 0 to 255)
      k-=5;  // deincreases of 5
      previousMillis = millis();  // the variable previousMillis stores the values of the millis () function
    }
  }
  k=255;  // assigns 255 to 'k'
}

////////////// function:  turn off the led ///////////////
void turnOff(int ledpin){
  analogWrite (ledpin, 0);
}