// ============================================================
//  SMART WEATHER STATION + AUTO VENTILATION
//  Arduino UNO | Wokwi Simulation
//
//  Parts (all verified from Wokwi docs):
//    wokwi-dht22          → temp + humidity sensor
//    wokwi-lcd1602 (i2c)  → 16x2 display
//    wokwi-servo          → auto vent flap (opens when hot)
//    wokwi-led (x3)       → status LEDs: green/yellow/red
//    wokwi-buzzer         → alarm when temp critical
//    wokwi-pushbutton     → cycle display screens
//
//  Libraries: DHT sensor library, LiquidCrystal I2C, Servo
// ============================================================

#include <DHT.h>
#include <Wire.h>
#include <LiquidCrystal_I2C.h>
#include <Servo.h>

// ── Pin definitions ──────────────────────────────────────
#define DHT_PIN     7
#define DHT_TYPE    DHT22
#define SERVO_PIN   9
#define LED_GREEN   2
#define LED_YELLOW  3
#define LED_RED     4
#define BUZZER_PIN  5
#define BTN_PIN     6

// ── Objects ───────────────────────────────────────────────
DHT           dht(DHT_PIN, DHT_TYPE);
LiquidCrystal_I2C lcd(0x27, 16, 2);
Servo         ventServo;

// ── State ─────────────────────────────────────────────────
float tempC     = 0;
float humidity  = 0;
float heatIndex = 0;
int   ventAngle = 0;       // 0 = closed, 90 = half, 170 = fully open
int   screen    = 0;       // 0=temp/hum, 1=heat index, 2=vent status
bool  alarmOn   = false;

unsigned long lastRead   = 0;
unsigned long lastBlink  = 0;
unsigned long lastBuzz   = 0;
bool          blinkState = false;

bool prevBtn = HIGH;
unsigned long dbBtn = 0;

// ── Custom LCD characters ─────────────────────────────────
// Thermometer icon
uint8_t thermChar[8] = {
  0b00100, 0b01010, 0b01010, 0b01110,
  0b01110, 0b11111, 0b11111, 0b01110
};
// Droplet icon
uint8_t dropChar[8] = {
  0b00100, 0b00100, 0b01010, 0b01010,
  0b10001, 0b10001, 0b10001, 0b01110
};
// Fan icon
uint8_t fanChar[8] = {
  0b00000, 0b01110, 0b11011, 0b00100,
  0b11011, 0b01110, 0b00000, 0b00000
};
// Up arrow
uint8_t upArrow[8] = {
  0b00100, 0b01110, 0b11111, 0b00100,
  0b00100, 0b00100, 0b00100, 0b00000
};

// ── Helpers ───────────────────────────────────────────────
// Compute heat index (simplified Steadman)
float computeHeatIndex(float t, float h) {
  return -8.78469 + 1.61139*t + 2.33855*h
         - 0.14612*t*h - 0.01230*t*t
         - 0.01642*h*h + 0.00221*t*t*h
         + 0.00072*t*h*h - 0.00000358*t*t*h*h;
}

// Map temperature to vent angle
int tempToVent(float t) {
  if (t < 25.0) return 0;          // cool  → closed
  if (t < 30.0) return map((int)(t*10), 250, 300, 0,  60);  // warm → partial
  if (t < 38.0) return map((int)(t*10), 300, 380, 60, 160);  // hot  → wide
  return 170;                       // critical → fully open
}

// Draw a bar on LCD row using filled/empty blocks
void drawBar(int col, int row, int percent, int width) {
  int filled = (percent * width) / 100;
  lcd.setCursor(col, row);
  for (int i = 0; i < width; i++) {
    lcd.write(i < filled ? (uint8_t)255 : (uint8_t)'-');
  }
}

// ── Screens ───────────────────────────────────────────────
void showScreenTemp() {
  // Row 0: therm icon + temperature
  lcd.setCursor(0, 0);
  lcd.write((uint8_t)0);           // thermometer
  lcd.print(" Temp: ");
  if (tempC < 10) lcd.print(" ");
  lcd.print(tempC, 1);
  lcd.print("\xDF""C ");

  // Row 1: drop icon + humidity bar
  lcd.setCursor(0, 1);
  lcd.write((uint8_t)1);           // droplet
  lcd.print(" Hum:");
  lcd.print((int)humidity);
  lcd.print("% ");
  drawBar(11, 1, (int)humidity, 5);
}

void showScreenHeatIdx() {
  lcd.setCursor(0, 0);
  lcd.print("Heat Index:     ");
  lcd.setCursor(0, 1);
  if (heatIndex < 27)      lcd.print("Comfort  ");
  else if (heatIndex < 32) lcd.print("Caution  ");
  else if (heatIndex < 41) lcd.print("Warning! ");
  else                     lcd.print("DANGER!! ");
  lcd.print(heatIndex, 1);
  lcd.print("\xDF""C");
}

void showScreenVent() {
  lcd.setCursor(0, 0);
  lcd.write((uint8_t)2);           // fan icon
  lcd.print(" Vent: ");
  int pct = map(ventAngle, 0, 170, 0, 100);
  lcd.print(pct);
  lcd.print("%   ");

  lcd.setCursor(0, 1);
  lcd.print("[");
  drawBar(1, 1, pct, 12);
  lcd.setCursor(13, 1);
  lcd.print("]  ");
}

// ── Setup ─────────────────────────────────────────────────
void setup() {
  dht.begin();

  lcd.init();
  lcd.backlight();
  lcd.createChar(0, thermChar);
  lcd.createChar(1, dropChar);
  lcd.createChar(2, fanChar);
  lcd.createChar(3, upArrow);

  ventServo.attach(SERVO_PIN);
  ventServo.write(0);

  pinMode(LED_GREEN,  OUTPUT);
  pinMode(LED_YELLOW, OUTPUT);
  pinMode(LED_RED,    OUTPUT);
  pinMode(BUZZER_PIN, OUTPUT);
  pinMode(BTN_PIN,    INPUT_PULLUP);

  // Splash screen
  lcd.setCursor(2, 0);
  lcd.print("WeatherStation");
  lcd.setCursor(3, 1);
  lcd.print("Auto Vent v1");
  delay(1800);
  lcd.clear();

  // Boot LED test
  digitalWrite(LED_GREEN,  HIGH); delay(200);
  digitalWrite(LED_YELLOW, HIGH); delay(200);
  digitalWrite(LED_RED,    HIGH); delay(200);
  digitalWrite(LED_GREEN,  LOW);
  digitalWrite(LED_YELLOW, LOW);
  digitalWrite(LED_RED,    LOW);

  lastRead = millis();
}

// ── Loop ──────────────────────────────────────────────────
void loop() {
  unsigned long now = millis();

  // ---- Read sensor every 2 s ----
  if (now - lastRead >= 2000) {
    lastRead = now;
    float t = dht.readTemperature();
    float h = dht.readHumidity();
    if (!isnan(t) && !isnan(h)) {
      tempC    = t;
      humidity = h;
      heatIndex = computeHeatIndex(t, h);
    }

    // ---- Update vent servo ----
    int targetAngle = tempToVent(tempC);
    // Smooth movement: step 5° per cycle toward target
    if (ventAngle < targetAngle) ventAngle = min(ventAngle + 5, targetAngle);
    else if (ventAngle > targetAngle) ventAngle = max(ventAngle - 5, targetAngle);
    ventServo.write(ventAngle);

    // ---- Update LEDs ----
    if (tempC < 28) {
      digitalWrite(LED_GREEN,  HIGH);
      digitalWrite(LED_YELLOW, LOW);
      digitalWrite(LED_RED,    LOW);
      alarmOn = false;
    } else if (tempC < 35) {
      digitalWrite(LED_GREEN,  LOW);
      digitalWrite(LED_YELLOW, HIGH);
      digitalWrite(LED_RED,    LOW);
      alarmOn = false;
    } else {
      digitalWrite(LED_GREEN,  LOW);
      digitalWrite(LED_YELLOW, LOW);
      alarmOn = true;
    }

    // ---- Refresh LCD screen ----
    lcd.clear();
    switch (screen) {
      case 0: showScreenTemp();    break;
      case 1: showScreenHeatIdx(); break;
      case 2: showScreenVent();    break;
    }
  }

  // ---- Red LED blink + buzzer when alarm ----
  if (alarmOn && now - lastBlink >= 300) {
    lastBlink = now;
    blinkState = !blinkState;
    digitalWrite(LED_RED, blinkState ? HIGH : LOW);
  }
  if (alarmOn && now - lastBuzz >= 800) {
    lastBuzz = now;
    tone(BUZZER_PIN, 1200, 120);
  }

  // ---- Button: cycle screens ----
  bool btn = digitalRead(BTN_PIN);
  if (prevBtn == HIGH && btn == LOW && now - dbBtn > 200) {
    screen = (screen + 1) % 3;
    dbBtn = now;
    lcd.clear();
    switch (screen) {
      case 0: showScreenTemp();    break;
      case 1: showScreenHeatIdx(); break;
      case 2: showScreenVent();    break;
    }
  }
  prevBtn = btn;

  delay(20);
}