#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>

#define OLED_RESET -1 
#define SCREEN_ADDRESS 0x3C
#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64

#define RED_LED 0
#define YELLOW_LED 2
#define DOUBLE_YELLOW_LED 4
#define GREEN_LED 16

int red_signal = 0;
int yellow_signal = 2;
int double_yellow_signal = 4;
int green_signal = 16;

Adafruit_SSD1306 oled(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);

boolean stop_train() {
  // Receive command from surver
  boolean stop_train = true;
  return stop_train;
}

int signal() {
 // Take signal data  from surver 
  int signal = 2;
  return signal;
}

long speed() {
  // Take train speed from GPS
  long speed = 90;
  return speed;
}

void setup() {
  pinMode(RED_LED, OUTPUT);
  pinMode(YELLOW_LED, OUTPUT);
  pinMode(DOUBLE_YELLOW_LED, OUTPUT);
  pinMode(GREEN_LED, OUTPUT);

  Serial.begin(9600);
  
  // initialize OLED display with I2C address 0x3C
  if (!oled.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {
    Serial.println(F("failed to start SSD1306 OLED"));
    while (1);
  }

}

void loop() {
  int current_signal = signal();

  if (current_signal == 1) {
    delay(2000);
    long allowed_speed_limit = 120;
    if (speed() > allowed_speed_limit) {
      // Send info to nearby station
      Serial.begin(115200);
      Serial.println("Train is overspeeding");
      // Receive command  from surver
      if (stop_train() == true) {
        // Give command to reduce train speed
        Serial.begin(115200);
        Serial.println("Command to reduce train speed");
        digitalWrite(YELLOW_LED, HIGH);

            
        oled.clearDisplay(); // clear display
        oled.setTextSize(1);         // set text size
        oled.setTextColor(WHITE);    // set text color
        oled.setCursor(0, 0); 
        oled.println("VOILATED Yellow signal");
        oled.setTextSize(1);         // set text size
        oled.setTextColor(WHITE);    // set text color
        oled.setCursor(0, 20);       // set position to display
        oled.println("Train is overspeeding"); // set text
        oled.setTextSize(1);         // set text size
        oled.setTextColor(WHITE);    // set text color
        oled.setCursor(0, 40); 
        oled.println("reduce train speed TO 120km/h");

        
        oled.display();              // display on OLED
        
        
      } else {
        // Everything is fine
        Serial.begin(115200);
        Serial.println("Everything is fine");
        digitalWrite(GREEN_LED, HIGH);
          
        oled.clearDisplay(); // clear display
        oled.setTextSize(1);         // set text size
        oled.setTextColor(WHITE);    // set text color
        oled.setCursor(0,20); 
        oled.println("Have a safe journey");
        oled.setTextSize(1);         // set text size
        oled.setTextColor(WHITE);    // set text color
        oled.setCursor(0, 40); 
        oled.println("signal is Green");
        
        
        oled.display();              // display on OLED
       }
    } else {
      // Everything is fine
      Serial.begin(115200);
      Serial.println("Everything is fine");
      digitalWrite(GREEN_LED, HIGH);
        
      oled.clearDisplay(); // clear display
      oled.setTextSize(1);         // set text size
      oled.setTextColor(WHITE);    // set text color
      oled.setCursor(0, 20); 
      oled.println("Have a safe journey");
      oled.setTextSize(1);         // set text size
      oled.setTextColor(WHITE);    // set text color
      oled.setCursor(0, 40); 
      oled.println("signal is Green");
    
      
      oled.display();              // display on OLED
      
    
    }
  }

  else if (current_signal == 2) {
    delay(2000);
    int allowed_speed_limit = 80;
    if (speed() > allowed_speed_limit) {
      // Send info to nearby station
      Serial.begin(115200);
      Serial.println("Train is overspeeding");
      // Receive command  from surver
      if (stop_train() == true) {
        // Give command to reduce train speed
        Serial.begin(115200);
        Serial.println("Command to reduce train speed");
        digitalWrite(YELLOW_LED, HIGH);
        digitalWrite(DOUBLE_YELLOW_LED, HIGH);

                 // wait two seconds for initializing
        oled.clearDisplay(); // clear display
        oled.setTextSize(1);         // set text size
        oled.setTextColor(WHITE);    // set text color
        oled.setCursor(0, 0); 
        oled.println(" Yellow Signal");
        oled.setTextSize(1);         // set text size
        oled.setTextColor(WHITE);    // set text color
        oled.setCursor(0, 20);       // set position to display
        oled.println("Train is overspeeding"); // set text
        oled.setTextSize(1);         // set text size
        oled.setTextColor(WHITE);    // set text color
        oled.setCursor(0, 40); 
        oled.println("reduce train speed TO 80km/h");

        
        oled.display();              // display on OLED
        
      
      } else {
        // Everything is fine
        Serial.begin(115200);
        Serial.println("Everything is fine");
        digitalWrite(GREEN_LED, HIGH);
          
        oled.clearDisplay(); // clear display
        oled.setTextSize(1);         // set text size
        oled.setTextColor(WHITE);    // set text color
        oled.setCursor(0, 20); 
        oled.println("Have a safe journey");
        oled.setTextSize(1);         // set text size
        oled.setTextColor(WHITE);    // set text color
        oled.setCursor(0, 40); 
        oled.println("signal is Yellow");

        
        oled.display();              // display on OLED
        
        
      }
    } else {
      // Everything is fine
      Serial.begin(115200);
      Serial.println("Everything is fine");
      digitalWrite(GREEN_LED, HIGH);
        
      oled.clearDisplay(); // clear display
      oled.setTextSize(1);         // set text size
      oled.setTextColor(WHITE);    // set text color
      oled.setCursor(0, 20); 
      oled.println("Have a safe journey");
      oled.setTextSize(1);         // set text size
      oled.setTextColor(WHITE);    // set text color
      oled.setCursor(0, 40); 
      oled.println("signal is Yellow");

      
      oled.display();              // display on OLED
      
      
    }
  }

  else if (current_signal == 4) {
    int allowed_speed_limit = 40;
    if (speed() > allowed_speed_limit) {
      // Send info to nearby station
      Serial.begin(115200);
      Serial.println("Train is overspeeding");
      // Receive command  from surver      
      if (stop_train() == true) {
        // Give command to apply brake
        Serial.begin(115200);
        Serial.println("Command to apply brake");
        digitalWrite(RED_LED, HIGH);

        
        oled.clearDisplay(); // clear display
        oled.setTextSize(1);         // set text size
        oled.setTextColor(WHITE);    // set text color
        oled.setCursor(0, 0); 
        oled.println("Vilated double yellow Signal");
        oled.setTextSize(1);         // set text size
        oled.setTextColor(WHITE);    // set text color
        oled.setCursor(40, 20);       // set position to display
        oled.println("Danger alert"); // set text
        oled.setTextSize(1);         // set text size
        oled.setTextColor(WHITE);    // set text color
        oled.setCursor(0, 40); 
        oled.println("reduce train speed TO 40km/h");

        
        oled.display();              // display on OLED
        
      
      } else {
        // Everything is fine
        Serial.begin(115200);
        Serial.println("Everything is fine");
        digitalWrite(GREEN_LED, HIGH);
          
        oled.clearDisplay(); // clear display
        oled.setTextSize(1);         // set text size
        oled.setTextColor(WHITE);    // set text color
        oled.setCursor(0, 20); 
        oled.println("Have a safe journey");
        oled.setTextSize(1);         // set text size
        oled.setTextColor(WHITE);    // set text color
        oled.setCursor(0, 40); 
        oled.println("signal is Double yellow");

        
        oled.display();              // display on OLED
        
    
      }
    } else {
      // Everything is fine
      Serial.begin(115200);
      Serial.println("Everything is fine");
      digitalWrite(GREEN_LED, HIGH);
        
      oled.clearDisplay(); // clear display
      oled.setTextSize(1);         // set text size
      oled.setTextColor(WHITE);    // set text color
      oled.setCursor(0, 20); 
      oled.println("Have a safe journey");
      oled.setTextSize(1);         // set text size
      oled.setTextColor(WHITE);    // set text color
      oled.setCursor(0, 40); 
      oled.println("signal is Double Yellow");

      
      oled.display();              // display on OLED
      
    
    }
  }
  else if (current_signal == 3) {
    int allowed_speed_limit = 0;
    if (speed() > allowed_speed_limit) {
      // Send info to nearby station
      Serial.begin(115200);
      Serial.println("Train is overspeeding");
      // Receive command  from surver      
      if (stop_train() == true) {
        // Give command to apply brake
        Serial.begin(115200);
        Serial.println("Command to apply brake");
        digitalWrite(RED_LED, HIGH);
                 // wait two seconds for initializing
        oled.clearDisplay(); // clear display
        oled.setTextSize(1);         // set text size
        oled.setTextColor(WHITE);    // set text color
        oled.setCursor(0, 0); 
        oled.println("Voilated Red Signal");
        oled.setTextSize(1);         // set text size
        oled.setTextColor(WHITE);    // set text color
        oled.setCursor(0, 20);       // set position to display
        oled.println("Exceed the STOP Signal"); // set text
        oled.setTextSize(1);         // set text size
        oled.setTextColor(WHITE);    // set text color
        oled.setCursor(0, 40); 
        oled.println("Stop the train");

        
        oled.display();              // display on OLED
        

      } else {
        // Everything is fine
        Serial.begin(115200);
        Serial.println("Everything is fine");
        digitalWrite(GREEN_LED, HIGH);
          
        oled.clearDisplay(); // clear display
        oled.setTextSize(1);         // set text size
        oled.setTextColor(WHITE);    // set text color
        oled.setCursor(0, 20); 
        oled.println("Have a safe journey");
        oled.setTextSize(1);         // set text size
        oled.setTextColor(WHITE);    // set text color
        oled.setCursor(0, 40); 
        oled.println("signal is red");

        
        oled.display();              // display on OLED
        
      
      }
    } else {
      // Everything is fine
      Serial.begin(115200);
      Serial.println("Everything is fine");
      digitalWrite(GREEN_LED, HIGH);
        
      oled.clearDisplay(); // clear display
      oled.setTextSize(1);         // set text size
      oled.setTextColor(WHITE);    // set text color
      oled.setCursor(0, 20); 
      oled.println("Have a safe journey");
      oled.setTextSize(1);         // set text size
      oled.setTextColor(WHITE);    // set text color
      oled.setCursor(0, 40); 
      oled.println("signal is red");

      
      oled.display();              // display on OLED
      
      
    }
  }

}