from machine import Pin, time_pulse_us, I2C
from ssd1306 import SSD1306_I2C
import time

class UltrassonicSensor:
    def __init__(self, trig_pin: int, echo_pin: int):
        self.__trig_pin = Pin(trig_pin, Pin.OUT)
        self.__echo_pin = Pin(echo_pin, Pin.IN)

    def read_distance_cm(self):
        self.__trig_pin.value(0)
        time.sleep_us(2)
        self.__trig_pin.value(1)
        time.sleep_us(10)
        self.__trig_pin.value(0)

        duration_us = time_pulse_us(self.__echo_pin, 1)        
        distance_cm = duration_us / 58.0

        return distance_cm

ultrassonic = UltrassonicSensor(4, 5)
luminous_display = {
    "critico": Pin(27, Pin.OUT),
    "alerta": Pin(26, Pin.OUT),
    "normal": Pin(25, Pin.OUT)
}

i2c = I2C(scl=Pin(22), sda=Pin(21))
OLED_W = 128
OLED_H = 64
oled_display = SSD1306_I2C(OLED_W, OLED_H, i2c)

CISTERN_HEIGHT_CM = 400
distance_to_water_cm = 0
full_height_cm_water = 0
situation = ''

oled_display.fill(0)
oled_display.text("Iniciando...", 0, 5)
time.sleep(1)
oled_display.show()

def get_situation(liters: float):
    if liters < 20:
        return 'critico'
    
    if liters < 40:
        return 'alerta'

    return 'normal'

for k in luminous_display:
    luminous_display[k].off()

while True:
    distance_to_water_cm = ultrassonic.read_distance_cm()

    if distance_to_water_cm > 400:
        distance_to_water_cm = 400

    full_height_cm_water = CISTERN_HEIGHT_CM - distance_to_water_cm
    situation = get_situation(full_height_cm_water)

    for k in luminous_display:
        if k == situation:
            luminous_display[k].on() 
        else:
            luminous_display[k].off() 

    oled_display.fill(0)
    oled_display.text(situation.upper(), 0, 5)
    oled_display.text(f'{round(full_height_cm_water)} LITROS', 0, 20)
    oled_display.show()

    time.sleep(0.2)