from machine import Pin, time_pulse_us, SoftI2C
from time import sleep_us, sleep
import ssd1306

# =========================
# OLED
# =========================
i2c = SoftI2C(scl=Pin(22), sda=Pin(21))
oled = ssd1306.SSD1306_I2C(128, 64, i2c)

# =========================
# ULTRASONIC
# =========================
TRIG = Pin(26, Pin.OUT)
ECHO = Pin(25, Pin.IN)

# =========================
# LED (ACTIVE LOW)
# =========================
GREEN = Pin(18, Pin.OUT)
YELLOW = Pin(19, Pin.OUT)
RED = Pin(23, Pin.OUT)

# =========================
# RELAY
# =========================
RELAY = Pin(27, Pin.OUT)

# =========================
# TURN OFF ALL
# ACTIVE LOW
# =========================
GREEN.value(1)
YELLOW.value(1)
RED.value(1)

# =========================
# DISTANCE FUNCTION
# =========================
def get_distance():

    TRIG.off()
    sleep_us(2)

    TRIG.on()
    sleep_us(10)
    TRIG.off()

    duration = time_pulse_us(ECHO, 1, 30000)

    if duration < 0:
        return 0

    distance = duration / 58

    return distance

# =========================
# MAIN LOOP
# =========================
while True:

    distance = get_distance()

    # ==================================
    # OFF ALL LED FIRST
    # ==================================
    GREEN.value(1)
    YELLOW.value(1)
    RED.value(1)

    RELAY.value(0)

    # ==================================
    # CONDITION
    # ==================================
    if distance > 300:

        status = "DANGER"

        RED.value(0)      # RED ON
        RELAY.value(1)

    elif distance >= 150 and distance <= 300:

        status = "WARNING"

        YELLOW.value(0)   # YELLOW ON

    else:

        status = "SAFE"

        GREEN.value(0)    # GREEN ON

    print("Distance:", distance)
    print("Status:", status)

    # ==================================
    # OLED DISPLAY
    # ==================================
    oled.fill(0)

    oled.text("FLOOD SYSTEM", 0, 0)

    oled.text("Distance:", 0, 20)
    oled.text(str(round(distance, 1)), 0, 32)
    oled.text("cm", 40, 32)

    oled.text("Status:", 0, 50)
    oled.text(status, 60, 50)

    oled.show()

    sleep(1)