from machine import Pin, PWM
import time

# ── 부품 설정 ──
trig = Pin(16, Pin.OUT)
echo = Pin(17, Pin.IN)

r = PWM(Pin(10)); r.freq(1000)
g = PWM(Pin(11)); g.freq(1000)
b = PWM(Pin(12)); b.freq(1000)

buzzer = PWM(Pin(5))
buzzer.duty_u16(0)

# ── 거리 구간 설정 ──
LEVELS = [
    # (최대거리, 색상(R,G,B), 경고음 간격, 상태)
    (10,  (255,   0,   0), 0.00, '위험'),
    (25,  (255,  60,   0), 0.10, '매우 근접'),
    (50,  (255, 200,   0), 0.30, '근접'),
    (90,  (120, 255,   0), 0.60, '주의'),
    (999, (  0, 255,   0), None, '안전'),
]

# ── 함수 ──
def get_distance():
    """거리를 cm로 반환. 실패하면 -1"""
    trig.low()
    time.sleep_us(2)
    trig.high()
    time.sleep_us(10)
    trig.low()

    t0 = time.ticks_us()
    while echo.value() == 0:
        start = time.ticks_us()
        if time.ticks_diff(start, t0) > 30000:
            return -1
    while echo.value() == 1:
        end = time.ticks_us()
        if time.ticks_diff(end, start) > 30000:
            return -1

    return (time.ticks_diff(end, start) * 0.0343) / 2

def color(rgb):
    """(R, G, B) 0~255 값으로 색 지정"""
    r.duty_u16(int(rgb[0] / 255 * 65535))
    g.duty_u16(int(rgb[1] / 255 * 65535))
    b.duty_u16(int(rgb[2] / 255 * 65535))

def find_level(d):
    """거리에 맞는 구간을 찾아 반환"""
    for limit, rgb, gap, name in LEVELS:
        if d < limit:
            return rgb, gap, name
    return LEVELS[-1][1], LEVELS[-1][2], LEVELS[-1][3]

def beep(gap):
    """gap 간격으로 한 번 경고음. gap이 0이면 연속음"""
    if gap == 0:
        buzzer.freq(2000)
        buzzer.duty_u16(20000)
        time.sleep(0.2)
    else:
        buzzer.freq(1500)
        buzzer.duty_u16(20000)
        time.sleep(0.06)
        buzzer.duty_u16(0)
        time.sleep(gap)

# ── 메인 ──
try:
    while True:
        d = get_distance()

        if d < 0:                      # 측정 실패
            color((0, 0, 40))          # 희미한 파랑
            buzzer.duty_u16(0)
            time.sleep(0.2)
            continue

        rgb, gap, name = find_level(d)
        color(rgb)

        if gap is None:                # 안전 구간
            buzzer.duty_u16(0)
            time.sleep(0.2)
        else:
            beep(gap)

        print(f'{d:5.1f} cm  {name}')

except KeyboardInterrupt:
    buzzer.duty_u16(0)
    color((0, 0, 0))
    print('종료')