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

static const int PIN_SOIL   = 34;
static const int PIN_LED_R  = 25;
static const int PIN_LED_Y  = 26;
static const int PIN_LED_G  = 27;
static const int PIN_RELAY  = 32;
static const int PIN_BUZZ   = 33;

static const int DANGER_MAX = 30;
static const int WARN_MAX   = 60;

static const unsigned long PUMP_RUN_MS      = 8000;
static const unsigned long PUMP_COOLDOWN_MS = 12000;

static const int RELAY_ON  = HIGH;
static const int RELAY_OFF = LOW;

bool pumpOn = false;
unsigned long pumpStopAt = 0;
unsigned long nextPumpAllowedAt = 0;

bool beepState = false;
unsigned long lastBeepToggle = 0;
int lastMode = -1;

uint8_t lcdAddr = 0x27;
LiquidCrystal_I2C lcd(0x27, 16, 2);

static bool i2cPing(uint8_t addr) {
  Wire.beginTransmission(addr);
  return (Wire.endTransmission() == 0);
}

static int moisturePercentFromRaw(int raw) {
  // In Wokwi, 3.3V behaves like ~2703 counts if ADC full-scale is 5V
  const int ADC_MAX_FOR_3V3 = 2703;

  raw = constrain(raw, 0, ADC_MAX_FOR_3V3);

  long pct = 100L - (long)raw * 100L / ADC_MAX_FOR_3V3;  // wet -> higher %
  pct = constrain((int)pct, 0, 100);
  return (int)pct;
}


static const char* statusFromPct(int pct) {
  if (pct < DANGER_MAX) return "DANGER";
  if (pct < WARN_MAX)   return "WARN";
  return "SAFE";
}

static void setIndicators(int pct) {
  digitalWrite(PIN_LED_R, (pct < DANGER_MAX) ? HIGH : LOW);
  digitalWrite(PIN_LED_Y, (pct >= DANGER_MAX && pct < WARN_MAX) ? HIGH : LOW);
  digitalWrite(PIN_LED_G, (pct >= WARN_MAX) ? HIGH : LOW);
}

// RED: continuous high tone
// YELLOW: slow beeps (lower tone)
// SAFE: off
static void buzzerByLevel(int pct) {
  int mode;
  if (pct < DANGER_MAX) mode = 2;
  else if (pct < WARN_MAX) mode = 1;
  else mode = 0;

  if (mode != lastMode) {
    lastMode = mode;
    beepState = false;
    lastBeepToggle = millis();
    noTone(PIN_BUZZ);
  }

  if (mode == 0) {
    noTone(PIN_BUZZ);
    return;
  }

  if (mode == 2) {
    tone(PIN_BUZZ, 2000);
    return;
  }

  const unsigned long intervalMs = 500;
  const int freq = 1200;

  unsigned long now = millis();
  if (now - lastBeepToggle >= intervalMs) {
    lastBeepToggle = now;
    beepState = !beepState;
    if (beepState) tone(PIN_BUZZ, freq);
    else noTone(PIN_BUZZ);
  }
}

static void pumpControl(int pct) {
  unsigned long now = millis();

  if (pumpOn && now >= pumpStopAt) {
    pumpOn = false;
    digitalWrite(PIN_RELAY, RELAY_OFF);
    nextPumpAllowedAt = now + PUMP_COOLDOWN_MS;
  }

  if (!pumpOn && pct < DANGER_MAX && now >= nextPumpAllowedAt) {
    pumpOn = true;
    digitalWrite(PIN_RELAY, RELAY_ON);
    pumpStopAt = now + PUMP_RUN_MS;
  }
}

static void lcdShow(int pct, const char* st) {
  lcd.setCursor(0, 0);
  lcd.print("Moist: ");
  if (pct < 100) lcd.print(" ");
  if (pct < 10)  lcd.print(" ");
  lcd.print(pct);
  lcd.print("%   ");

  lcd.setCursor(0, 1);
  lcd.print("St:");
  lcd.print(st);
  lcd.print(" Pump:");
  lcd.print(pumpOn ? "ON " : "OFF");
}

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

  pinMode(PIN_LED_R, OUTPUT);
  pinMode(PIN_LED_Y, OUTPUT);
  pinMode(PIN_LED_G, OUTPUT);

  pinMode(PIN_RELAY, OUTPUT);
  digitalWrite(PIN_RELAY, RELAY_OFF);

  pinMode(PIN_BUZZ, OUTPUT);
  noTone(PIN_BUZZ);

  analogReadResolution(12);

  Wire.begin(21, 22);

  if (i2cPing(0x27)) lcdAddr = 0x27;
  else if (i2cPing(0x3F)) lcdAddr = 0x3F;

  lcd = LiquidCrystal_I2C(lcdAddr, 16, 2);
  lcd.init();
  lcd.backlight();
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Smart Watering");
  lcd.setCursor(0, 1);
  lcd.print("Ready");
  delay(800);
  lcd.clear();
}

void loop() {
  int rawSum = 0;
  for (int i = 0; i < 8; i++) rawSum += analogRead(PIN_SOIL);
  int raw = rawSum / 8;

  int pct = moisturePercentFromRaw(raw);
  const char* st = statusFromPct(pct);

  setIndicators(pct);
  buzzerByLevel(pct);
  pumpControl(pct);
  lcdShow(pct, st);

  Serial.print("raw=");
  Serial.print(raw);
  Serial.print(" pct=");
  Serial.print(pct);
  Serial.print("% st=");
  Serial.print(st);
  Serial.print(" pump=");
  Serial.println(pumpOn ? "ON" : "OFF");

  delay(200);
}