/*
Lab 2 Challenging Content

Vraj Patel, Makeda Morrison
Lab Section: MAE 311-01
Due Date: June 23, 2025
*/

const int switchPin = 2;  // monitors pin 2
const int ledPin = 11;  // The LED is on pin 11
int buttonState;  // Remembers state of the button
int lightState = 0;  // Remembers state of the LED (starts off)
int blinkState = LOW;  // stores initial state of blinking LED
long previousMillis = 0;  // stores last time the LED was updated
long interval = 1000;  // blinking interval in milliseconds
unsigned long currentMillis = 0;  // start the timer at 0
int blinkStrength;  // PWM strength variable for State 2

void setup() {
  pinMode(switchPin, INPUT);  // Set the switch pin as input
  pinMode(ledPin, OUTPUT);  // Set the LED pin as an output
  Serial.begin(9600);  // Set up serial communication at 9600 bps
  buttonState = digitalRead(switchPin);  // read the initial state
}

void loop() {
  int val = digitalRead(switchPin);  // read input value and store it in val
  delay(10);  // waits 10 milliseconds to read the switch again
  int val2 = digitalRead(switchPin);  // second read of the switch
  if (val == val2) {  // ensure it was really a press
    if (val != buttonState) {  // The button state has changed
      if (val == LOW) {  // check if the button is being pressed 
        if (lightState == 0) {  // check if the light is off
          lightState = 1;  // set the blink mode to ON
          Serial.println("Button just pressed, Blinking");
          currentMillis = 0;  // sets the start time to 0
          previousMillis = 0;  // sets the current time to zero
          blinkState = LOW;  // ensures that the LED variable is off
        }
        else if (lightState == 1) {  // button is pressed again, going to state 2 (slow blinks)
          lightState = 2;  // set blink mode to long blinks
          Serial.println("Button pressed again, long blinks");
          currentMillis = 0;  // reset start timer to 0
          previousMillis = 0;  // reset current time to zero
          blinkStrength = 0;  // set PWM strength to zero
        }
        else if (lightState == 2) {  // button is pressed again, go to state 3 (continuously on)
          lightState = 3;  // set blink mode to continuously on
          Serial.println("Button pressed again, continuously on");
          blinkState = HIGH;  // ensures LED will be on
        }

      else {  // button pressed in State 3, go back to initial off state
        lightState = 0;  // sets the state to OFF
        digitalWrite(ledPin, LOW);  // turn LED off
        blinkState = LOW;  // set the led variable off
        Serial.println("Button just pressed, light off");
      }
    }
  }
}

//    BLINKING SECTION START //

if (lightState == 1) {  // if the blink mode is active, do this
  currentMillis = millis();  // record the current time
  if (currentMillis - previousMillis > interval) {  // compare start and current time, only execute if greater than set blink interval time
    previousMillis = currentMillis;  // set the timer equal since blink interval is reached
    if (blinkState == LOW)  // if the led is off, then
      blinkState = HIGH;  // turn it on
      else 
        blinkState = LOW;  // turn it off
      digitalWrite(ledPin, blinkState);  // actually turns it off or on
    }
  }

else if (lightState == 2) {  // do this if long blink mode is active
  currentMillis = millis();  // record current time
  if ((currentMillis - previousMillis) < interval) { // if it hasn't been 1 second since button press (gradually increasing brightness)
  // There is a 10 ms delay built into each loop of this script during the debounce button check, so factoring that in,
  // in 1 second this loop will run 1000ms/10ms = 100 times. To go from 0-255 PWM strength in 100 cycles, each cycle must increase
  // PWM strength by 255/100 units, as shown beloww
    blinkStrength += 255/(interval/10); 
  }
  else if (((currentMillis - previousMillis) >= interval) && ((currentMillis - previousMillis) <= 2*interval)) {  // if it has been more than a second but less than 2 seconds (decreasing brightness)
    blinkStrength -= 255/(interval/10);  // same process as increasing, but decrease strength this time
  }
  else {  // it has been more than 2 seconds, reset long blink cycle
    previousMillis = currentMillis;  // set timers equal again since interval complete
    blinkStrength = 0;  // reset PWM strength to zero
  }
  analogWrite(ledPin, blinkStrength);  // actually dim or brighten the light
}

else {   // covers states 3 and 4
  digitalWrite(ledPin, blinkState);
}

//   BLINKING SECTION END   //

  buttonState = val;  // save the new state in our variable

}