#include <WiFi.h>
#include <HTTPClient.h>
#include <DHT.h>
#include <HX711.h>

// Pin definitions
#define DHTPIN 4
#define DHTTYPE DHT22
#define HX711_DT 16
#define HX711_SCK 17
#define DOOR_SENSOR_PIN 5

// Sensor objects
DHT dht(DHTPIN, DHTTYPE);
HX711 scale;

// WiFi credentials
const char* ssid = "Wokwi-GUEST";
const char* password = "";
const char* serverUrl = "https://smart-fridge-two.vercel.app/api/sensors";

// HX711 Calibration - ADJUST THESE FOR YOUR LOAD CELL
// For 50kg load cell, typical values are between -400 to -7500
float CALIBRATION_FACTOR = 420.0;  // Start with this, adjust as needed

// Timing
unsigned long lastSendTime = 0;
const unsigned long sendInterval = 2000;

// Sensor status
bool dht_working = false;
bool hx711_working = false;

// DHT22 retry settings
int dht_fail_count = 0;
const int MAX_DHT_FAILS = 3;

void setup() {
  Serial.begin(115200);
  delay(2000);
  
  Serial.println("\n\n╔════════════════════════════════════╗");
  Serial.println("║   SMART FRIDGE SYSTEM STARTING   ║");
  Serial.println("╚════════════════════════════════════╝\n");
  
  // Door sensor
  pinMode(DOOR_SENSOR_PIN, INPUT_PULLUP);
  Serial.println("✓ Door sensor ready (GPIO " + String(DOOR_SENSOR_PIN) + ")");
  
  // DHT22 initialization
  Serial.println("\n--- Initializing DHT22 ---");
  Serial.println("Pin: GPIO " + String(DHTPIN));
  dht.begin();
  delay(2500);
  
  for (int i = 0; i < 3; i++) {
    float testTemp = dht.readTemperature();
    float testHum = dht.readHumidity();
    
    if (!isnan(testTemp) && !isnan(testHum)) {
      dht_working = true;
      Serial.println("✓ DHT22 WORKING!");
      Serial.println("  Temperature: " + String(testTemp, 2) + " °C");
      Serial.println("  Humidity: " + String(testHum, 2) + " %");
      break;
    } else {
      Serial.println("  Attempt " + String(i+1) + "/3 failed...");
      delay(1000);
    }
  }
  
  if (!dht_working) {
    Serial.println("✗ DHT22 FAILED - Will retry during operation");
  }
  
  // HX711 initialization
  Serial.println("\n--- Initializing HX711 (50kg Load Cell) ---");
  Serial.println("DT Pin: GPIO " + String(HX711_DT));
  Serial.println("SCK Pin: GPIO " + String(HX711_SCK));
  
  scale.begin(HX711_DT, HX711_SCK);
  delay(1000);
  
  if (scale.wait_ready_timeout(3000)) {
    Serial.println("✓ HX711 detected!");
    
    long raw = scale.read_average(10);
    Serial.println("  Raw reading: " + String(raw));
    
    if (raw != 0 && abs(raw) > 1000) {
      // Set calibration
      scale.set_scale(CALIBRATION_FACTOR);
      delay(500);
      
      // Tare (zero) the scale
      Serial.println("  Taring scale (remove all weight)...");
      delay(2000);
      scale.tare(20);
      delay(500);
      
      float testWeight = scale.get_units(10);
      Serial.println("  Test reading: " + String(testWeight, 2) + " kg");
      
      hx711_working = true;
      Serial.println("✓ HX711 READY!");
      Serial.println("  Calibration factor: " + String(CALIBRATION_FACTOR));
      Serial.println("  Note: Adjust CALIBRATION_FACTOR if readings are wrong");
    } else {
      Serial.println("✗ HX711 invalid reading");
    }
  } else {
    Serial.println("✗ HX711 TIMEOUT");
  }
  
  // WiFi connection
  Serial.println("\n--- Connecting to WiFi ---");
  Serial.println("SSID: " + String(ssid));
  
  WiFi.mode(WIFI_STA);
  WiFi.disconnect();
  delay(100);
  WiFi.begin(ssid, password);
  
  int wifi_attempts = 0;
  Serial.print("Connecting");
  while (WiFi.status() != WL_CONNECTED && wifi_attempts < 40) {
    delay(500);
    Serial.print(".");
    wifi_attempts++;
  }
  Serial.println();
  
  if (WiFi.status() == WL_CONNECTED) {
    Serial.println("✓✓✓ WIFI CONNECTED! ✓✓✓");
    Serial.println("  IP: " + WiFi.localIP().toString());
    Serial.println("  Signal: " + String(WiFi.RSSI()) + " dBm");
  } else {
    Serial.println("✗ WiFi FAILED");
  }
  
  // Setup summary
  Serial.println("\n╔════════════════════════════════════╗");
  Serial.println("║       SETUP COMPLETE SUMMARY      ║");
  Serial.println("╠════════════════════════════════════╣");
  Serial.println("║ DHT22:  " + String(dht_working ? "✓ WORKING " : "✗ OFFLINE ") + "            ║");
  Serial.println("║ HX711:  " + String(hx711_working ? "✓ WORKING " : "✗ OFFLINE ") + "            ║");
  Serial.println("║ Door:   ✓ WORKING             ║");
  Serial.println("║ WiFi:   " + String(WiFi.status() == WL_CONNECTED ? "✓ CONNECTED" : "✗ OFFLINE  ") + "           ║");
  Serial.println("╚════════════════════════════════════╝\n");
  
  delay(1000);
}

void loop() {
  unsigned long currentTime = millis();
  
  if (currentTime - lastSendTime >= sendInterval) {
    lastSendTime = currentTime;
    
    Serial.println("┌────────────────────────────────────┐");
    Serial.println("│     SENSOR READING CYCLE           │");
    Serial.println("└────────────────────────────────────┘");
    
    // ===== READ DHT22 WITH RETRY LOGIC =====
    float temp = -999;
    float humidity = -999;
    bool temp_valid = false;
    
    if (dht_working || dht_fail_count < MAX_DHT_FAILS) {
      // Try reading twice with delay
      for (int attempt = 0; attempt < 2; attempt++) {
        temp = dht.readTemperature();
        humidity = dht.readHumidity();
        
        if (!isnan(temp) && !isnan(humidity)) {
          temp_valid = true;
          dht_working = true;
          dht_fail_count = 0;
          break;
        }
        
        if (attempt == 0) {
          delay(500);  // Wait before retry
        }
      }
      
      if (!temp_valid) {
        dht_fail_count++;
        if (dht_fail_count >= MAX_DHT_FAILS) {
          dht_working = false;
          Serial.println("✗ DHT22 DISCONNECTED (multiple failures)");
        } else {
          Serial.println("⚠ DHT22 read failed, will retry...");
        }
      }
    }
    
    if (temp_valid) {
      Serial.println("Temperature: " + String(temp, 1) + " °C [REAL]");
      Serial.println("Humidity:    " + String(humidity, 1) + " % [REAL]");
    } else {
      Serial.println("Temperature: DISCONNECTED ✗");
      Serial.println("Humidity:    DISCONNECTED ✗");
      temp = -999;
      humidity = -999;
    }
    
    // ===== READ HX711 WITH VALIDATION =====
    float weight = -999;
    bool weight_valid = false;
    
    if (hx711_working) {
      if (scale.wait_ready_timeout(1000)) {
        // Get reading with multiple samples
        weight = scale.get_units(5);
        
        // Validate reading
        if (!isnan(weight)) {
          // Filter out noise - values very close to zero
          if (abs(weight) < 0.05) {
            weight = 0.0;
          }
          
          // If weight is negative and more than -0.5, likely calibration issue
          // Re-tare if needed
          if (weight < -0.5) {
            Serial.println("⚠ Negative weight detected, re-taring...");
            scale.tare(10);
            delay(500);
            weight = scale.get_units(5);
            if (abs(weight) < 0.05) weight = 0.0;
          }
          
          weight_valid = true;
        }
      } else {
        Serial.println("⚠ HX711 timeout");
        hx711_working = false;
      }
    }
    
    if (weight_valid) {
      Serial.println("Weight:      " + String(weight, 2) + " kg [REAL]");
    } else {
      Serial.println("Weight:      DISCONNECTED ✗");
      weight = -999;
    }
    
    // ===== READ DOOR SENSOR =====
    bool doorOpen = digitalRead(DOOR_SENSOR_PIN) == LOW;
    Serial.println("Door:        " + String(doorOpen ? "OPEN ⚠️" : "CLOSED ✓"));
    
    // ===== SEND DATA TO SERVER =====
    Serial.println();
    
    if (WiFi.status() == WL_CONNECTED) {
      HTTPClient http;
      http.setTimeout(8000);
      http.begin(serverUrl);
      http.addHeader("Content-Type", "application/json");
      
      // Build JSON
      String jsonData = "{";
      jsonData += "\"temperature\":" + String(temp, 2) + ",";
      jsonData += "\"humidity\":" + String(humidity, 2) + ",";
      jsonData += "\"weight\":" + String(weight, 2) + ",";
      jsonData += "\"doorOpen\":" + String(doorOpen ? "true" : "false") + ",";
      jsonData += "\"pressure\":" + String(weight > 0 ? weight : 0.0, 2) + ",";
      jsonData += "\"gasLevel\":0";
      jsonData += "}";
      
      Serial.println("→ Sending to server...");
      Serial.println("  Data: " + jsonData);
      
      int httpCode = http.POST(jsonData);
      
      if (httpCode == 200) {
        Serial.println("✓✓✓ DATA SENT SUCCESSFULLY! ✓✓✓");
        String response = http.getString();
        Serial.println("Server: " + response);
      } else if (httpCode > 0) {
        Serial.println("⚠ HTTP Code: " + String(httpCode));
      } else {
        Serial.println("✗ Send failed: " + http.errorToString(httpCode));
      }
      
      http.end();
    } else {
      Serial.println("✗ WiFi disconnected - reconnecting...");
      WiFi.disconnect();
      delay(100);
      WiFi.begin(ssid, password);
      
      int attempts = 0;
      while (WiFi.status() != WL_CONNECTED && attempts < 10) {
        delay(500);
        attempts++;
      }
      
      if (WiFi.status() == WL_CONNECTED) {
        Serial.println("✓ Reconnected!");
      }
    }
    
    Serial.println("════════════════════════════════════\n");
  }
}