/*
  Project: Smart Traffic Light 

  Description:
  This project focuses on designing a smart traffic light system that manages
  normal traffic flow while enhancing accessibility and safety for visually
  impaired or disabled pedestrians.

  Objectives:
  - Provide standard traffic light functionality for vehicle control.
  - Use sensor to detect vehicles and optimize signal timing.
  - Prioritize crossing for people with disabilities (especially the visually impaired)
    through  interaction.
    ---------------------------------
  Note: 
  please be aware that you might experience delays, limited functionality, or slower  performance
  These issues are more common in free version , which may not fully
  support real-time execution or advanced features.

  For a smoother experience, consider using paid version or testing directly
  on hardware whenever possible.

  developed by Rababe Ben Abdelhadi
*/

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

// OLED Display settings
#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, -1);

// Define GPIO pins for lights
int redLightDriver = 12; 
int yellowLightDriver = 14; 
int greenLightDriver = 27; 
int redLightPedestrian = 16; 
int greenLightPedestrian = 17; 
int buttonPin = 4;

// Ultrasonic Sensor (HC-SR04) Pins
int trigPin = 5;  
int echoPin = 18;  

// Timing variables
int defaultTrafficTime = 10;  // Default countdown for traffic lights
int pedestrianTime = 10;       // Countdown for pedestrian crossing
bool pedestrianRequested = false;

// Global distance variable
int distance = 0;  

void setup() {
    Serial.begin(115200);

    // Pin Modes
    pinMode(redLightDriver, OUTPUT);
    pinMode(yellowLightDriver, OUTPUT);
    pinMode(greenLightDriver, OUTPUT);
    pinMode(redLightPedestrian, OUTPUT);
    pinMode(greenLightPedestrian, OUTPUT);
    pinMode(buttonPin, INPUT_PULLUP);  
    pinMode(trigPin, OUTPUT);
    pinMode(echoPin, INPUT);

    // OLED Initialization
    if (!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) { 
        Serial.println("SSD1306 initialization failed!");
        for (;;);
    }
    display.clearDisplay();
    display.setTextSize(2);
    display.setTextColor(WHITE);
    display.display();
}

void prepare() {
    for (int i = 0; i < 3; i++) {
        digitalWrite(yellowLightDriver, HIGH);
        delay(500);
        digitalWrite(yellowLightDriver, LOW);
        delay(500);
    }
}

int getTrafficDuration() {
    digitalWrite(trigPin, LOW);
    delayMicroseconds(2);
    digitalWrite(trigPin, HIGH);
    delayMicroseconds(10);
    digitalWrite(trigPin, LOW);

    long duration = pulseIn(echoPin, HIGH);
    distance = duration * 0.034 / 2;  // Update global distance variable

    if (distance < 20) {  
        Serial.println("🚗 Vehicle detected! Extending green light.");
        return defaultTrafficTime + 5;
    }
    return defaultTrafficTime;
}

void displayCountdown(String mode, int g,int timeLeft) {
    display.clearDisplay();
    display.setCursor(10, 10);
    display.print(mode); 
    display.setCursor(10, 25);
    display.print(g);
    display.setCursor(10, 40);
    display.print("Time: ");
    display.print(timeLeft);
    display.display();
}


void light() {
    Serial.println("🚦 Normal Traffic Mode");
    digitalWrite(greenLightDriver, HIGH);
    digitalWrite(yellowLightDriver, LOW);
    digitalWrite(redLightDriver, LOW);
    digitalWrite(greenLightPedestrian, LOW);
    digitalWrite(redLightPedestrian, HIGH);
    
    int timeRemaining = getTrafficDuration();
    for (int i = timeRemaining; i > 0; i--) {
        displayCountdown("distance:",distance, i);
        if (digitalRead(buttonPin) == LOW) {
            Serial.println("🟢 Button Press Detected! Switching to Pedestrian Mode.");
            pedestrianRequested = true;
            return;
        }
        delay(1000);
    }

    digitalWrite(greenLightDriver, LOW);
    prepare();
    digitalWrite(redLightDriver, HIGH);
    digitalWrite(greenLightPedestrian, HIGH);
    digitalWrite(redLightPedestrian, LOW);

    for (int i = pedestrianTime; i > 0; i--) {
        displayCountdown("distance:",distance,i);
        
        delay(1000);
    }

    digitalWrite(greenLightPedestrian, LOW);
    digitalWrite(redLightPedestrian, HIGH);
}

void blindfeat() {
    Serial.println("🔵 Pedestrian Mode Activated!");
    
    digitalWrite(greenLightDriver, LOW);
    prepare();
    
    digitalWrite(redLightPedestrian, LOW);
    digitalWrite(greenLightPedestrian, HIGH);
    digitalWrite(redLightDriver, HIGH);
    

    for (int i = pedestrianTime; i > 0; i--) {  
        displayCountdown( "distance:",distance,i);
        
        delay(1000);
    }

    digitalWrite(redLightDriver, LOW);
    prepare();

    digitalWrite(greenLightDriver, HIGH);
    digitalWrite(redLightPedestrian, HIGH);
    digitalWrite(greenLightPedestrian, LOW);
    
    pedestrianRequested = false;
}

void loop() {
    
  
    if (digitalRead(buttonPin) == LOW) {
        Serial.println("🟢 Button Press Detected! Switching to Pedestrian Mode.");
        pedestrianRequested = true;
        
    }

    if (pedestrianRequested) {
        
        blindfeat();
        
    } else {
        
        light();
        
    }
}