// ============================================================
// Bijli Chor Hunter — Wokwi Simulation Version
// NMIMS MPSTME | B.Tech CSE Sem IV | AY 2025-26
// ============================================================

#include <Arduino.h>
#include <WiFi.h>
#include <HTTPClient.h>

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

// ThingSpeak Configuration
const char* apiKey   = "B7F6M6LX19V0AHYU";
const char* server   = "http://api.thingspeak.com/update";

// Timing Variables for ThingSpeak
unsigned long lastUpload = 0;
const unsigned long UPLOAD_INTERVAL = 15000; // 15 seconds

// ─── Pin Definitions ───
#define PIN_SOURCE    34    // Pot 1 wiper → simulates ACS712 Source
#define PIN_LOAD      35    // Pot 2 wiper → simulates ACS712 Load
#define PIN_VOLTAGE   32    // Pot 3 wiper → simulates ZMPT101B
#define LED_GREEN      2    // Normal state indicator
#define LED_YELLOW     4    // Line Fault indicator
#define LED_RED        5    // Power Theft indicator
#define BUZZER        18    // Active buzzer
#define PIN_THEFT_SWITCH 27

// ─── Calibration Constants ───
const float SENSITIVITY  = 0.185;   // ACS712-05B: 185mV/A
const float VCC          = 3.3;     // ESP32 ADC reference voltage
const float ADC_MAX      = 4095.0;  // 12-bit ADC
const float DELTA_THRESH = 0.5;     // Theft threshold (Amps)
const float VOLT_THRESH  = 180.0;   // Fault voltage threshold (V)
const float VOLT_FACTOR  = 218.5;   // ZMPT101B calibration factor
const int   SAMPLES      = 500;     

// ─── RMS Current Calculation ───
float getRMSCurrent(int pin) {
  float sum = 0;
  for (int i = 0; i < SAMPLES; i++) {
    float voltage = (analogRead(pin) / ADC_MAX) * VCC;
    float current = (voltage - (VCC / 2.0)) / SENSITIVITY;
    sum += current * current;
  }
  return sqrt(sum / SAMPLES);
}

// ─── RMS Voltage Calculation ───
float getRMSVoltage(int pin) {
  float sum = 0;
  for (int i = 0; i < SAMPLES; i++) {
    float v = (analogRead(pin) / ADC_MAX) * VCC;
    sum += v * v;
  }
  return sqrt(sum / SAMPLES) * VOLT_FACTOR;
}

void setup() {
  Serial.begin(115200);
  pinMode(LED_GREEN,  OUTPUT);
  pinMode(LED_YELLOW, OUTPUT);
  pinMode(LED_RED,    OUTPUT);
  pinMode(BUZZER,     OUTPUT);
  pinMode(PIN_THEFT_SWITCH, INPUT_PULLUP);

  // WiFi Connection Setup
  WiFi.begin(ssid, password);
  Serial.print("Connecting to WiFi");
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  Serial.println("\nWiFi Connected!");

  Serial.println("=====================================");
  Serial.println(" Bijli Chor Hunter - Wokwi Simulation");
  Serial.println("=====================================");
}

void loop() {
  // ─── Reset all outputs ───
  digitalWrite(LED_GREEN,  LOW);
  digitalWrite(LED_YELLOW, LOW);
  digitalWrite(LED_RED,    LOW);
  digitalWrite(BUZZER,     LOW);
  // ─── Read Sensors ───
  float Is     = getRMSCurrent(PIN_SOURCE);
  float IL     = getRMSCurrent(PIN_LOAD);
  float V      = getRMSVoltage(PIN_VOLTAGE);
  
  // ─── MID-LINE THEFT SIMULATION ───
  // If the switch is flipped, add 1.5A to the source reading
  if (digitalRead(PIN_THEFT_SWITCH) == LOW) {
      Is = Is + 1.5; 
  }

  float deltaI = abs(Is - IL);

  // ─── Detection Logic ───
  int status = 0;
  String stateName = "";

  if (V < VOLT_THRESH && deltaI >= DELTA_THRESH) {
    status = 3; stateName = "*** FAULT + THEFT ***";
    digitalWrite(LED_RED,    HIGH);
    digitalWrite(LED_YELLOW, HIGH);
    digitalWrite(BUZZER,     HIGH);
  } else if (V < VOLT_THRESH) {
    status = 2; stateName = "!!! LINE FAULT !!!";
    digitalWrite(LED_YELLOW, HIGH);
    digitalWrite(BUZZER,     HIGH);
  } else if (deltaI >= DELTA_THRESH) {
    status = 1; stateName = ">>> POWER THEFT <<<";
    digitalWrite(LED_RED,    HIGH);
    digitalWrite(BUZZER,     HIGH);
  } else {
    status = 0; stateName = "[ NORMAL ]";
    digitalWrite(LED_GREEN,  HIGH);
  }

  // ─── Serial Monitor Output ───
  Serial.println("-------------------------------------");
  Serial.printf("Is = %.3f A | IL = %.3f A | V = %.1f V\n", Is, IL, V);
  Serial.printf("STATUS: %s\n", stateName.c_str());

  // ─── ThingSpeak Upload (Non-blocking) ───
  if (millis() - lastUpload >= UPLOAD_INTERVAL) {
    if (WiFi.status() == WL_CONNECTED) {
      HTTPClient http;
      // Using String() conversion for reliability
      String url = String(server) + "?api_key=" + String(apiKey)
                   + "&field1=" + String(Is)
                   + "&field2=" + String(IL)
                   + "&field3=" + String(V)
                   + "&field4=" + String(deltaI)
                   + "&field5=" + String(status);
      
      http.begin(url);
      int httpCode = http.GET();
      
      if (httpCode > 0) {
        Serial.printf("ThingSpeak Update Successful (%d)\n", httpCode);
      } else {
        Serial.printf("ThingSpeak Error: %s\n", http.errorToString(httpCode).c_str());
      }
      http.end();
      lastUpload = millis(); // Reset timer after upload attempt
    } else {
      Serial.println("WiFi Disconnected. Skipping Upload.");
    }
  }

  delay(500); // Short delay to keep the loop responsive
}