from machine import Pin,time_pulse_us
import time
import os

time.sleep(0.1) # Wait for USB to become ready

print("Hello by Pi Pico 2. Let's start!")
print(os.listdir())

'''
# =====================================================================
# ΑΥΤΟΜΑΤΗ ΔΙΟΡΘΩΣΗ ΓΙΑ ΤΟ WOKWI (Δημιουργία εικονικού δίσκου στη μνήμη)
# =====================================================================
try:
    os.stat('tank200.csv')
except OSError:
    try:
        print('trying2')
        import vfs
        from flashbdev import bdev
        vfs.VfsLfs2.mkfs(bdev)
        vfs.mount(bdev, '/')
        print("Wokwi Storage Initialized Successfully!")
    except Exception:
        print('trying3')
        # Εναλλακτική μέθοδος αν η flashbdev δεν υποστηρίζεται στον εξομοιωτή
        try:
            os.mount(Flash(), '/')
        except:
            print('trying4')
            pass
# =====================================================================
'''
Trig_Pin = 10 # Connected to GP10
Echo_Pin = 11 # Connecter to GP11

Full_Tank_H = 10 # Heigth from top of the water when tank is full in cm
Empty_Tank_H = 92-12 # Heigth from top of the water when level is at the nozzle in cm
Drained_Tank_H = 92 # Heigth from top of the water when no water at all in cm (probably is not needed)

# Initialize Pin State
trig = Pin(Trig_Pin, mode = Pin.OUT)
echo = Pin(Echo_Pin, mode = Pin.IN)

def log_data(percentage, distance):
    """Saves the measurements to a local CSV file on the Pico 2."""
    try:
        with open("tank200.csv", "a") as f:
            # Χρήση του time.ticks_ms() για σχετικό χρόνο λειτουργίας 
            timestamp = time.ticks_ms() / 1000 
            f.write("{:.1f},{:.1f},{:.1f}\n".format(timestamp, distance, percentage))
            f.close()
    except Exception as e:
        print("Logging error:", e)


def get_level_height():
    """Triggers the ultrasonic sensor and returns measured distance in cm."""
    # Ensure trigger is low
    trig.value(0)
    time.sleep_us(5) #sleep_us in microseconds, sleep_ms in miliseconds
    
    # Send a 10 microsecond pulse to trigger and then back to zero state
    trig.value(1) #0,1 for FALSE,TRUE states
    time.sleep_us(10)
    trig.value(0)
    
    # Measure the duration of the incoming echo pulse
    duration = time_pulse_us(echo, 1, 30000) # 30ms timeout, expected value 1. This function has outout -2
    # if the value 1 is never met, and -1 if the measurement goes longer than 30ms
    
    if duration < 0:
        return duration # Timeout / Error
        
    # Speed of sound is ~343 m/s or 0.0343 cm/microsec. 
    # Divide by 2 because the sound wave travels to the object and back.
    distance = (duration * 0.0343) / 2
    return distance



print("--- Starting Raspberry Pi Pico 2 Water Level Monitor ---")

try:
    with open("tank200.csv", "w") as f:
        f.write("Timestamp(s),Distance(cm),Level(%)\n")
        f.close()
except Exception as e:
    print("Could not initialize log file:", e)


xx=0
while xx<=10:
    dist = get_level_height()
    
    if dist == -1:
        print("Sensor error: Sensor can not be initialized.")
    elif dist == -2:
        print("Sensor error: Out of range receiving signal.")
    else:
        # Calculate water level percentage
        # Closer distance means a fuller tank
        if dist > Empty_Tank_H:
            water_level_pct = 0.0
        elif dist < Full_Tank_H:
            water_level_pct = 100.0
        else:
            # Map the distance linearly to a percentage
            total_range = Empty_Tank_H - Full_Tank_H
            current_fill = Empty_Tank_H - dist
            water_level_pct = (current_fill / total_range) * 100.0
            
        print(u"Distance to water: {:.1f} cm | Tank Level: {:.1f}%".format(dist, water_level_pct))
        
        
        #log_data(water_level_pct, dist) # CSV log
        xx=xx+1


    time.sleep(1) # Refresh every second