from machine import Pin, ADC, I2C
import time

# =========================================================
# GAS LEAKAGE ALARM
# Raspberry Pi Pico + MQ-2 + LCD 16x2 I2C
# LED Hijau + LED Merah + Buzzer
# START + RESET
# =========================================================

# KONFIGURASI PIN
# MQ-2
mq2 = ADC(26)  # GP26/ADC0

# LED
led_hijau = Pin(14, Pin.OUT)
led_merah = Pin(15, Pin.OUT)

# Tombol (Menggunakan internal PULL-UP)
button_start = Pin(16, Pin.IN, Pin.PULL_UP)
button_reset = Pin(17, Pin.IN, Pin.PULL_UP)

# Buzzer
buzzer = Pin(18, Pin.OUT)

# LCD I2C
i2c = I2C(0, scl=Pin(5), sda=Pin(4), freq=400000)

# KONFIGURASI LCD
LCD_ADDR = 0x27

# BATAS GAS MANUAL
# MASUKKAN NILAI ADC BATAS BAHAYA DI SINI
# =========================================================
BATAS_GAS = 25000

# VARIABEL SISTEM
# =========================================================
sistem_aktif = False


# CLASS LCD 16x2 I2C
class LCD1602:

  def __init__(self, i2c, addr):
    self.i2c = i2c
    self.addr = addr
    self.init_lcd()

  def write_byte(self, data):
    self.i2c.writeto(self.addr, bytes([data]))

  def pulse_enable(self, data):
    self.write_byte(data | 0x04)
    time.sleep_us(500)
    self.write_byte(data & ~0x04)
    time.sleep_us(100)

  def send_nibble(self, nibble, mode=0):
    data = nibble | mode | 0x08
    self.write_byte(data)
    self.pulse_enable(data)

  def send(self, value, mode=0):
    self.send_nibble(value & 0xF0, mode)
    self.send_nibble((value << 4) & 0xF0, mode)

  def command(self, cmd):
    self.send(cmd, 0)

  def write_char(self, char):
    self.send(ord(char), 1)

  def clear(self):
    self.command(0x01)
    time.sleep_ms(2)

  def move_to(self, row, col):
    if row == 0:
      address = 0x80 + col
    else:
      address = 0xC0 + col
    self.command(address)

  def putstr(self, text):
    for char in text:
      self.write_char(char)

  def init_lcd(self):
    time.sleep_ms(50)
    self.send_nibble(0x30)
    time.sleep_ms(5)
    self.send_nibble(0x30)
    time.sleep_ms(1)
    self.send_nibble(0x30)
    time.sleep_ms(1)
    self.send_nibble(0x20)
    # 4-bit mode, 2 line
    self.command(0x28)
    # Display ON
    self.command(0x0C)
    # Cursor increment
    self.command(0x06)
    self.clear()


# INISIALISASI LCD
lcd = LCD1602(i2c, LCD_ADDR)


# FUNGSI MATIKAN OUTPUT
# =========================================================
def output_off():
  led_hijau.value(0)
  led_merah.value(0)
  buzzer.value(0)


# FUNGSI STANDBY
def standby_screen():
  output_off()
  lcd.clear()
  lcd.move_to(0, 0)
  lcd.putstr("SYSTEM STANDBY")
  lcd.move_to(1, 0)
  lcd.putstr("Tekan START")


# FUNGSI SISTEM AKTIF
def active_screen():
  lcd.clear()
  lcd.move_to(0, 0)
  lcd.putstr("ALARM AKTIF")
  lcd.move_to(1, 0)
  lcd.putstr("Monitoring...")


# STARTUP
output_off()
lcd.clear()
lcd.move_to(0, 0)
lcd.putstr("GAS DETECTOR")
lcd.move_to(1, 0)
lcd.putstr("SYSTEM START")
time.sleep(2)

# TAMPILKAN BATAS GAS
lcd.clear()
lcd.move_to(0, 0)
lcd.putstr("BATAS BAHAYA")
lcd.move_to(1, 0)
lcd.putstr("ADC:{:5d}".format(BATAS_GAS))

print("===========================")
print("       GAS DETECTOR        ")
print("===========================")
print("Batas bahaya ADC =", BATAS_GAS)
print("===========================")
time.sleep(3)

# MASUK STANDBY
sistem_aktif = False
standby_screen()

# =========================================================
# MAIN LOOP
# =========================================================
while True:
  # =========================================================
  # TOMBOL RESET
  # =========================================================
  if button_reset.value() == 0:
    # Debounce
    time.sleep_ms(50)
    if button_reset.value() == 0:
      print("RESET SYSTEM")
      # Matikan sistem
      sistem_aktif = False
      # Matikan semua output
      output_off()
      # Tampilkan standby
      standby_screen()
      # Tunggu tombol dilepas
      while button_reset.value() == 0:
        time.sleep_ms(10)

  # =========================================================
  # TOMBOL START
  # =========================================================
  if button_start.value() == 0:
    # Debounce
    time.sleep_ms(50)
    if button_start.value() == 0:
      print("SYSTEM START")
      # Aktifkan sistem
      sistem_aktif = True
      active_screen()
      # Tunggu tombol dilepas
      while button_start.value() == 0:
        time.sleep_ms(10)

  # =========================================================
  # SISTEM BELUM AKTIF
  # =========================================================
  if not sistem_aktif:
    output_off()
    time.sleep_ms(100)
    continue

  # =========================================================
  # BACA SENSOR MQ-2
  # =========================================================
  nilai_adc = mq2.read_u16()

  # SERIAL MONITOR
  # =========================================================
  print("ADC:", nilai_adc, "Batas:", BATAS_GAS)

  # =========================================================
  # KONDISI NORMAL
  # =========================================================
  if nilai_adc < BATAS_GAS:
    # LED HIJAU ON
    led_hijau.value(1)
    # LED MERAH OFF
    led_merah.value(0)
    # BUZZER OFF
    buzzer.value(0)
    # LCD
    lcd.clear()
    lcd.move_to(0, 0)
    lcd.putstr("STATUS: NORMAL")
    lcd.move_to(1, 0)
    lcd.putstr("ADC:{:5d}".format(nilai_adc))
    time.sleep_ms(500)

  # =========================================================
  # KONDISI BAHAYA
  # =========================================================
  else:
    # LED HIJAU OFF
    led_hijau.value(0)
    # LED MERAH ON
    led_merah.value(1)
    # LCD
    lcd.clear()
    lcd.move_to(0, 0)
    lcd.putstr("!!! GAS !!!")
    lcd.move_to(1, 0)
    lcd.putstr("ADC:{:5d}".format(nilai_adc))

    # Serial Monitor
    print("!!! BAHAYA !!! ADC =", nilai_adc)

    # BUZZER
    buzzer.value(1)
    time.sleep_ms(200)
    buzzer.value(0)
    time.sleep_ms(200)