#=======================================================
# NAME: WAN KHALISH HAIKAL BIN WAN HARISS
# STUDENT ID: 52227124124
# Project: Smart Gate - Final Version with Distance Display
#=======================================================

import machine
import utime
import ssd1306

# --- Hardware Configuration ---
# I2C0: SDA=GP0 (Pin 1), SCL=GP1 (Pin 2)
i2c = machine.I2C(0, scl=machine.Pin(1), sda=machine.Pin(0), freq=400000)
oled = ssd1306.SSD1306_I2C(128, 64, i2c)

# A4988 Stepper Driver: Step=GP14, Dir=GP15
step_pin = machine.Pin(14, machine.Pin.OUT)
dir_pin = machine.Pin(15, machine.Pin.OUT)

# HC-SR04 Ultrasonic Sensor: Trig=GP16, Echo=GP17
trig = machine.Pin(16, machine.Pin.OUT)
echo = machine.Pin(17, machine.Pin.IN)

# PIR Sensor: GP18
pir_pin = machine.Pin(18, machine.Pin.IN, machine.Pin.PULL_DOWN)

# --- Logic Constants ---
STEPS_PER_REV = 200
REV_LIMIT = 2
TOTAL_STEPS = STEPS_PER_REV * REV_LIMIT
STEP_DELAY = 1000 
DIST_THRESHOLD = 20 

# --- State Variables ---
current_dir = 0 # 0 for CW, 1 for CCW

def get_distance():
    """Calculates distance in cm using HC-SR04"""
    trig.low()
    utime.sleep_us(2)
    trig.high()
    utime.sleep_us(10)
    trig.low()
    
    # Wait for echo pulse
    while echo.value() == 0:
        signaloff = utime.ticks_us()
    while echo.value() == 1:
        signalon = utime.ticks_us()
    
    timepassed = signalon - signaloff
    distance = (timepassed * 0.0343) / 2
    return distance

def update_display(status, detail, extra=""):
    """Handles OLED visual updates"""
    oled.fill(0)
    # Header
    oled.text("  SMART GATE  ", 10, 0)
    oled.text("--------------", 8, 12) 
    
    # Content
    oled.text(status, 0, 28)
    oled.text(detail, 0, 42)
    oled.text(extra, 0, 56)
    oled.show()
    
    # Serial Monitor Feedback
    print(f"[LOG]: {status} | {detail} | {extra}")

# --- Main Program Boot ---
update_display("SYSTEM BOOT", "Pico W Active", "Ready...")
utime.sleep(1)

while True:
    try:
        dist = get_distance()
        motion = pir_pin.value()
        
        # Display current distance while scanning
        dist_str = "Dist: {:.1f}cm".format(dist)
        motion_str = "Motion: YES" if motion == 1 else "Motion: NO"
        
        # Check triggers: Motion OR Proximity
        if motion == 1 or dist < DIST_THRESHOLD:
            source = "MOTION DETECTED" if motion == 1 else "SONIC TRIGGER"
            action = "GATE OPENING" if current_dir == 0 else "GATE CLOSING"
            
            update_display("!! ALERT !!", source, action)
            
            # Execute Motor Rotation
            dir_pin.value(current_dir)
            for _ in range(TOTAL_STEPS):
                step_pin.value(1)
                utime.sleep_us(STEP_DELAY)
                step_pin.value(0)
                utime.sleep_us(STEP_DELAY)
            
            update_display("TASK COMPLETE", "Cooldown...", "")
            utime.sleep(2) # Prevent immediate re-trigger
            
            # Toggle direction for next run
            current_dir = 1 if current_dir == 0 else 0
            
        else:
            # Idle scanning mode - updates distance every 0.1s
            update_display("STATUS: SCANNING", dist_str, motion_str)
            
        utime.sleep(0.1)
        
    except Exception as e:
        print(f"Error in loop: {e}")
        utime.sleep(1)