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("==============================")
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)