//Recommend reading: https://www.arduino.cc/reference/en/
 
 //Buttons go 1-4 from Top to bottom
 
 //This project uses an Arduino Pro Micro (also known as an Arduino Leonardo)

//Includes
//These can be installed in the arduino IDE by clicking on tools in the top bar, then manage libraries.
#include <EasyButton.h>   //Used to define a button and debounces it
#include "HID-Project.h"  //Lets us simulate keyboard presses.


//Pin Definitions. These numbers refer to the physical GPIO pins on the board
//LEDS
#define LED1 3
#define LED2 5
#define LED3 6
#define LED4 9

//Buttons
#define BUTTON1 A3
#define BUTTON2 A2 
#define BUTTON3 A1
#define BUTTON4 A0

unsigned long ledTickTime = 0; 
unsigned long lastPressTime = 0; 
uint8_t ledBrightness = 100; 
bool ledOn = false;

//Using the EasyButton library we create 4 buttons, with each button being connected to a GPIO pin as defined above, and having a 35ms debounce time. From memory, these do not have internal pullup resistors, and are not inverted. Hence the two falses.
EasyButton button1(BUTTON1, 35, false, false);
EasyButton button2(BUTTON2, 35, false, false);
EasyButton button3(BUTTON3, 35, false, false);
EasyButton button4(BUTTON4, 35, false, false);

//Standard Arduino setup function. Code that only needs to run once goes here
void setup() {
  Keyboard.begin();
  
  //LEDS - Setting the LED pins to be outputs. Normally, the buttons would be set as inputs, but they are handled by that library.
  pinMode(LED1, OUTPUT);
  pinMode(LED2, OUTPUT);
  pinMode(LED3, OUTPUT);
  pinMode(LED4, OUTPUT);

  //Here we output a PWM signal to the LEDs, where 0 will be off, and 255 is brightest
  analogWrite(LED1, ledBrightness);
  analogWrite(LED2, ledBrightness);
  analogWrite(LED3, ledBrightness);
  analogWrite(LED4, ledBrightness);

  //BUTTONS - setup buttons using library.
  button1.begin();
  button2.begin();
  button3.begin();
  button4.begin();  
}


//Code that is run constantly goes here
void loop() {
  
  //Read all the buttons
  button1.read();
  button2.read();
  button3.read();
  button4.read();


  //This should be pretty self explanitory. Make sure to always release a button.
  if(button1.isPressed())
  {
    Keyboard.press(KEY_LEFT_ALT);
    lastPressTime = millis();
  }

  else if(button1.wasReleased())
  {
    Keyboard.release(KEY_LEFT_ALT);
    lastPressTime = millis();
  }

  if(button2.isPressed())
  {
    Keyboard.press(KEY_LEFT_CTRL);
    lastPressTime = millis();
  }

  else if(button2.wasReleased())
  {
    Keyboard.release(KEY_LEFT_CTRL);
    lastPressTime = millis();
  }

  if(button3.isPressed())
  {
    Keyboard.press(KEY_LEFT_SHIFT);
    lastPressTime = millis();
  }

  else if(button3.wasReleased())
  {
    Keyboard.release(KEY_LEFT_SHIFT);
    lastPressTime = millis();
  }

  if(button4.isPressed())
  {
    Keyboard.press(KEY_SPACE);
    lastPressTime = millis();
  }

  else if(button4.wasReleased())
  {
    Keyboard.release(KEY_SPACE);
    lastPressTime = millis();
  }

  if((millis() - lastPressTime) > 10000)
  {
    ledOn = false;
  }
  else 
  {
    ledOn = true;
  }
  
  if ((millis() - ledTickTime) > 10)
  {
    ledTickTime = millis();
    if(!ledOn && (ledBrightness > 0))
    {
      ledBrightness=ledBrightness-1;
    }
  
    else if(ledOn && (ledBrightness < 100))
    {
      ledBrightness=ledBrightness+10;
    }

    analogWrite(LED1, ledBrightness);
    analogWrite(LED2, ledBrightness);
    analogWrite(LED3, ledBrightness);
    analogWrite(LED4, ledBrightness); 
  }

//  Serial.print("Led Brightness = ");
//  Serial.print(ledBrightness);
//  Serial.print("\t Led State = ");
//  Serial.println(ledOn);

}