//Servo Libraries
#include <Servo.h>

//Keypad Libraries
#include <Keypad.h>

//OLED Libraries
#include <Wire.h>
#include <Adafruit_SSD1306.h>
#include <Adafruit_GFX.h>

//IR
#define IRIN 3
#define IROUT 2

//OLED
Adafruit_SSD1306 display(128, 64, &Wire, -1);

//Keypad
char keys[4][4] = {
  { '1', '2', '3', 'A' },
  { '4', '5', '6', 'B' },
  { '7', '8', '9', 'C' },
  { '*', '0', '#', 'D' }
};
byte pin_rows[4] = { 12, 10, 9, 8 };
byte pin_column[4] = { 7, 6, 5, 4 };
Keypad keypad = Keypad(makeKeymap(keys), pin_rows, pin_column, 4, 4);

//Servo
Servo ProServo;

//Visitors
volatile int visitors = 0;

//Password
String Input = "";  //Input

String passNorm = "0000";   //Normal Gate
String passOpen = "1111";   //Always Open Gate
String passClose = "2222";  //Always Closed Gate

//Variables
int irOut;

short flag = 0;  //Gate State (0: CLOSED) (1: OPEN) (2: ALWAYS OPEN) (3: ALWAYS CLOSED)

int threshold = 0;  //Visitor's Limit

int IRINREAD = 0;  //IRIN Value

int IROUTREAD = 0;  //IROUT Value
/*---------------------[Setup]-----------------------*/

void setup() {

  noInterrupts();

  //Serial Monitor
  Serial.begin(9600);

  //Servo
  ProServo.attach(11);
  ProServo.write(0);

  //IR
  pinMode(IRIN, INPUT);
  pinMode(IROUT, INPUT);
  IRINREAD = digitalRead(IRIN);
  IROUTREAD = digitalRead(IROUT);

  //Input
  Input.reserve(4);  //Password doesn't exceed 4 characters

  interrupts();

  //OLED
  display.begin(SSD1306_SWITCHCAPVCC, 0x3C);

  display.clearDisplay();
  display.setTextSize(2);
  display.setTextColor(WHITE);
  display.setCursor(21, 20);
  display.println(F("Welcome"));
  display.display();
  delay(3000);
  display.setTextSize(1);
}

/*---------------------[Loop]-----------------------*/

void loop() {

  Display();

  char key = keypad.getKey();

  if (INPUT == passNorm || key == NO_KEY) {  //Normal Mode 0000

    if (IRINREAD == HIGH) {  //IRIN
      ProServo.write(90);
      flag = 1;  //OPEN
      delay(250);
      while (true) {
        if (IRINREAD == LOW) {
          break;
        }
      }
      visitors++;
      ProServo.write(0);
      flag = 0;  //CLOSED
      delay(250);
    }

    if (IROUTREAD == HIGH) {
      ProServo.write(90);
      flag = 1;  //OPEN
      delay(250);
      while (true) {
        if (IROUTREAD == LOW) {  //IROUT
          break;
        }
      }
      visitors--;
      ProServo.write(0);
      flag = 0;  //CLOSED
      delay(250);
    }
  }

  if (key != NO_KEY) {

    Serial.print(key);

    if (key == '*') {
      Input = "";
    } else if (key == '#') {
      if (Input == passClose)  //Always Closed Gate 2222
      {
        closeGate();

      } else if (Input == passOpen)  //Always Open Gate 1111
      {
        openGate();

      } else  //Invalid Input
      {
        Invalid();
      }
    } else {
      Input += key;
    }
  }
}
/*---------------------[Gate Always Open State]-----------------------*/  //1111
void openGate() {
  if (INPUT == passOpen) {  //Always Open Mode 1111
    ProServo.write(90);
    if (IRINREAD == HIGH) {  //IRIN
      flag = 2;              //Always Open
      delay(250);
      while (true) {
        if (IRINREAD == LOW) {
          break;
        }
      }
      visitors++;
      delay(250);
    }

    if (IROUTREAD == HIGH) {
      flag = 2;  //Always Open
      delay(250);
      while (true) {
        if (IROUTREAD == LOW) {  //IROUT
          break;
        }
      }
      visitors--;
      delay(250);
    }
  }
}
/*---------------------[Gate Always Closed State]-----------------------*/  //2222
void closeGate() {
  if (INPUT == passClose) {  //Always Closed Mode 2222
    ProServo.write(0);
    if (IRINREAD == HIGH) {  //IRIN
      flag = 3;              //Always Close
      delay(250);
      while (true) {
        if (IRINREAD == LOW) {
          break;
        }
      }
      delay(250);
    }

    if (IROUTREAD == HIGH) {
      flag = 3;  //Always Close
      delay(250);
      while (true) {
        if (IROUTREAD == LOW) {  //IROUT
          break;
        }
      }
      delay(250);
    }
  }
}
/*---------------------[Display]-----------------------*/
void Display() {
  display.clearDisplay();
  display.setCursor(0, 0);
  display.println(F("State:"));

  //State
  if (flag == 0) {
    display.println(F("CLOSED"));
  } else if (flag == 1) {
    display.println(F("OPEN"));
  } else if (flag == 2) {
    display.println(F("ALWAYS OPEN"));
  } else if (flag == 3) {
    display.println(F("ALWAYS CLOSED"));
  }

  display.println(F("Visitors:"));
  display.println(visitors);
  display.display();
}
/*---------------------[Invalid Input]-----------------------*/
void Invalid() {
  display.setTextSize(2);
  //display.setTextColor(WHITE);
  display.clearDisplay();
  display.setCursor(23, 18);
  display.println(F("INVALID"));
  display.setCursor(35, 35);
  display.println(F("INPUT"));
  display.display();
  delay(3000);
  display.clearDisplay();
  display.setCursor(5, 20);
  display.println(F("Enter Code"));
  display.display();
  delay(3000);
}