from machine import Pin
import time

# ===== Display subsystem: HD44780 LCD =======================

RS = Pin(19, Pin.OUT)                  # Register Select
E  = Pin(18, Pin.OUT)                  # Enable

# Fix 1: Corrected LCD Data Pins order to match diagram.json (D4->5, D5->17, D6->16, D7->4)
DATA = [Pin(5, Pin.OUT),              # D4
        Pin(17, Pin.OUT),             # D5
        Pin(16, Pin.OUT),             # D6
        Pin(4, Pin.OUT)]              # D7

# ----- HD44780 command constants ------------------------------------------
LCD_CLEAR       = 0x01
LCD_HOME        = 0x02
LCD_ENTRY       = 0x04
ENTRY_LEFT      = 0x02
LCD_DISPLAY     = 0x08
DISPLAY_ON      = 0x04
LCD_FUNCTION    = 0x20
FUNC_4BIT_2LINE = 0x08
LCD_SET_DDRAM   = 0x80

ROW_ADDR = (0x00, 0x40)

def _pulse():
    E.value(1)
    time.sleep_us(1)
    E.value(0)
    time.sleep_us(50)

def _write4(nibble):
    for i in range(4):
        DATA[i].value((nibble >> i) & 1)
    _pulse()

def _send(value, is_data):
    RS.value(1 if is_data else 0)
    _write4(value >> 4)
    _write4(value & 0x0F)

def command(cmd):
    _send(cmd, False)
    if cmd in (LCD_CLEAR, LCD_HOME):
        time.sleep_ms(2)

def write_char(ch):
    _send(ord(ch), True)

def write_str(text):
    for ch in text:
        write_char(ch)

def set_cursor(col, row):
    command(0x80 | (ROW_ADDR[row] + col))

def lcd_init():
    time.sleep_ms(40)
    RS.value(0)
    _write4(0x03); time.sleep_ms(5)
    _write4(0x03); time.sleep_us(150)
    _write4(0x03)
    _write4(0x02)
    command(LCD_FUNCTION | FUNC_4BIT_2LINE)
    command(LCD_DISPLAY | DISPLAY_ON)
    command(LCD_CLEAR)
    command(LCD_ENTRY | ENTRY_LEFT)

# ===== Sensing subsystem: PIR Motion Sensor ===============================
# Fix 2: Changed PIR pin from 27 to 14 to match diagram.json
pir = Pin(14, Pin.IN)

# ===== Main program =======================================================
lcd_init()
set_cursor(0, 0)
write_str("Motion Alarm")

count = 0
last_motion = 0
last_lcd = time.ticks_ms()

print("Motion Alarm running. Waiting for the PIR...")

while True:
    motion = pir.value()

    # Fix 3: Fixed comparison operator from '=' to '=='
    if motion == 1 and last_motion == 0:
        count += 1
        print("Motion detected, count =", count)
    last_motion = motion

    now = time.ticks_ms()
    if time.ticks_diff(now, last_lcd) >= 200:
        last_lcd = now
        if motion == 1:
            line2 = "Motion: YES  " + str(count)
        else:
            line2 = "Motion: no   " + str(count)
        set_cursor(0, 1)
        write_str((line2 + " " * 16)[:16])

    time.sleep_ms(10)