#include <WiFi.h>
#include <HTTPClient.h>
#include "ThingSpeak.h"

// WiFi Credentials (Wokwi uses guest network)
const char* ssid = "Wokwi-GUEST";
const char* password = "";

// ThingSpeak Channel Details
unsigned long channelID = 2907195;
const char* writeAPIKey = "5WT98MTD0LL86TNQ";

// TalkBack Command
const int talkBackID = 54505;
const char* talkBackAPIKey = "NGNOYD8HJ5PGHX5B";

// WiFi client for ThingSpeak
WiFiClient client;

// Stepper Motor Pins
#define IN1 18
#define IN2 5
#define IN3 17
#define IN4 16

// Ultrasonic Sensor Pins
#define TRIG_PIN 12
#define ECHO_PIN 13

#define OBSTACLE_DISTANCE 20 // cm

// Half-step sequence
int steps[4][4] = {
  {1, 0, 1, 0},
  {0, 1, 1, 0},
  {0, 1, 0, 1},
  {1, 0, 0, 1}
};

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

  pinMode(IN1, OUTPUT);
  pinMode(IN2, OUTPUT);
  pinMode(IN3, OUTPUT);
  pinMode(IN4, OUTPUT);

  pinMode(TRIG_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);

  WiFi.begin(ssid, password);
  Serial.print("Connecting to WiFi");
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  Serial.println(" connected!");

  ThingSpeak.begin(client);
}

void loop() {
  long distance = measureDistance();
  Serial.print("Distance: ");
  Serial.print(distance);
  Serial.println(" cm");

  // Send distance to ThingSpeak
  ThingSpeak.setField(1, distance);
  int x = ThingSpeak.writeFields(channelID, writeAPIKey);
  if (x == 200) {
    Serial.println("✅ Data sent to ThingSpeak.");
  } else {
    Serial.print("❌ Failed to send data. HTTP error code: ");
    Serial.println(x);
  }

  // Get TalkBack Command
  String command = getTalkBackCommand();
  if (command.length() > 0) {
    Serial.print("TalkBack Command: ");
    Serial.println(command);
  }

  if (distance < OBSTACLE_DISTANCE && distance != 0) {
    stopMotor();
    Serial.println("🚧 Obstacle detected – motor stopped.");
  } else {
    if (command == "Clockwise") {
      rotateClockwise();
    } else if (command == "Anticlockwise") {
      rotateAntiClockwise();
    } else if (command == "Stop") {
      stopMotor();
      Serial.println("⛔ Motor stopped via TalkBack.");
    }
  }

  delay(15000); // ThingSpeak update interval
}

String getTalkBackCommand() {
  HTTPClient http;
  String commandURL = "http://api.thingspeak.com/talkbacks/" + String(talkBackID) + "/commands/execute";
  commandURL += "?api_key=" + String(talkBackAPIKey);

  http.begin(commandURL);
  int httpCode = http.GET();

  String command = "";
  if (httpCode == 200) {
    command = http.getString();
  } else {
    Serial.print("Failed to get TalkBack command. Error code: ");
    Serial.println(httpCode);
  }

  http.end();
  command.trim(); // Remove \n or extra space
  return command;
}

long measureDistance() {
  digitalWrite(TRIG_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);

  long duration = pulseIn(ECHO_PIN, HIGH, 30000);
  long distance = duration * 0.034 / 2;
  return distance;
}

void rotateClockwise() {
  for (int i = 0; i < 4; i++) {
    digitalWrite(IN1, steps[i][0]);
    digitalWrite(IN2, steps[i][1]);
    digitalWrite(IN3, steps[i][2]);
    digitalWrite(IN4, steps[i][3]);
    delay(5);
  }
}

void rotateAntiClockwise() {
  for (int i = 3; i >= 0; i--) {
    digitalWrite(IN1, steps[i][0]);
    digitalWrite(IN2, steps[i][1]);
    digitalWrite(IN3, steps[i][2]);
    digitalWrite(IN4, steps[i][3]);
    delay(5);
  }
}

void stopMotor() {
  digitalWrite(IN1, LOW);
  digitalWrite(IN2, LOW);
  digitalWrite(IN3, LOW);
  digitalWrite(IN4, LOW);
}