import threading
import time
import random

# Shared values
device_values = [0, 0]
value_lock = threading.Lock()

# Per-device pause controls
device_events = [threading.Event(), threading.Event()]
device_events[0].set()  # Start as running
device_events[1].set()

# Tolerance threshold
TOLERANCE = 20

# Stop flag
stop_event = threading.Event()

def is_within_tolerance(val_a, val_b):
    return abs(val_a - val_b) <= TOLERANCE

# Device thread
def device_thread(device_id):
    other_id = 1 - device_id
    while not stop_event.is_set():
        device_events[device_id].wait()  # Pause if needed

        # Simulate value from device
        new_value = random.randint(0, 100)

        with value_lock:
            device_values[device_id] = new_value
            my_val = device_values[device_id]
            other_val = device_values[other_id]

            print(f"Device {device_id} => {my_val} | Device {other_id} => {other_val}")

            if not is_within_tolerance(my_val, other_val):
                print(f"Device {device_id} is out of tolerance! Pausing...")
                device_events[device_id].clear()

        time.sleep(0.1)  # Faster check interval

# Watcher thread
def tolerance_watcher():
    while not stop_event.is_set():
        with value_lock:
            val0, val1 = device_values
            if is_within_tolerance(val0, val1):
                for i, event in enumerate(device_events):
                    if not event.is_set():
                        print(f"Resuming Device {i}")
                        event.set()

        time.sleep(0.05)  # Fast response

# Start threads
threads = [
    threading.Thread(target=device_thread, args=(0,)),
    threading.Thread(target=device_thread, args=(1,)),
    threading.Thread(target=tolerance_watcher)
]

for t in threads:
    t.start()

# Run loop (press Ctrl+C to stop)
try:
    while True:
        time.sleep(0.1)
except KeyboardInterrupt:
    print("Stopping...")

stop_event.set()
for event in device_events:
    event.set()

for t in threads:
    t.join()

print("All threads stopped.")