from machine import Pin,time_pulse_us
import time
import os
import modfile

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

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

ramdir = '/ramdisk'
ramdir = modfile.mkRAMfs(512,32) #initializing ram disk and obtain it's directory
print(os.listdir())

# Set the Pins
Trig_Pin = 10 # Connected HC-SR04 Trig to GP10
Echo_Pin = 11 # Connecter HC-SR04 Echo to GP11

RELAY_OPEN_PIN = 2    # Controls relay2 (Green LED / Open Valve)
RELAY_CLOSE_PIN = 15  # Controls relay1 (Red LED / Close Valve)


# Water Barrel dimensions
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)

# Spherical Valve times
VALVE_SPIN_TIME = 5     # 5 seconds to rotate the ball valve 90 degrees
VALVE_OPEN_DURATION = 30 # Simulated 30 "minutes" as 30 seconds for easy testing

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

# Standard safety initialization (0 Watts drawn)
relay_open.low()
relay_close.low()


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))
    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

def trigger_valve_cycle():
    """Runs the low-power 3-wire valve execution loop."""
    print("\n[CYCLE START] Target acquired within 20cm!")
    
    # 1. Open the valve
    print("⚡ Energizing OPEN wire (GP2 High - Green LED On)...")
    relay_close.low()   # Interlock safety check
    relay_open.high()
    time.sleep(VALVE_SPIN_TIME)
    
    # 2. Park the valve Open (0 Watts Idle draw)
    relay_open.low()
    print(f"🔒 Valve fully OPEN. Current cut to 0W. Waiting {VALVE_OPEN_DURATION}s...")
    
    time.sleep(VALVE_OPEN_DURATION)
    
    # 3. Close the valve
    print("⚡ Energizing CLOSE wire (GP15 High - Red LED On)...")
    relay_open.low()    # Interlock safety check
    relay_close.high()
    time.sleep(VALVE_SPIN_TIME)
    
    # 4. Park the valve Closed (0 Watts Idle draw)
    relay_close.low()
    print("🔒 Valve fully CLOSED. Current cut to 0W. System standing by.")


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

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


xx=0
while xx<=5:
    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
f.close()