1. 1
2. 2
3. 3
4. 4
5. 5
6. 6
7. 7
8. 8
9. 9
10. 10
11. 11
12. 12
13. 13
14. 14
15. 15
16. 16
17. 17
18. 18
19. 19
20. 20
21. 21
22. 22
23. 23
24. 24
25. 25
26. 26
27. 27
28. 28
29. 29
30. 30
31. 31
32. 32
33. 33
34. 34
35. 35
36. 36
37. 37
38. 38
39. 39
40. 40
41. 41
42. 42
43. 43
44. 44
45. 45
46. 46

def get_decrease_fan_speed_delta(fan_speed: float, delta: float, turn_off: bool):
    # if the fan is already running slower than minimum speed
    if fan_speed < MIN_FAN_SPEED:
        # we ignore the turn_off argument and always set the fan off
        return -fan_speed
    # if fan would be running slower than minimum speed after decreasing it by delta:
    if (fan_speed - delta) < MIN_FAN_SPEED:
        if turn_off:
            return -fan_speed  # turn the fan off
        else:
            return -fan_speed + MIN_FAN_SPEED  # make it run at minimum speed
    return -delta


def get_increase_fan_speed_delta(fan_speed, delta):
    new_fan_speed = fan_speed + delta
    # if fan would be running faster than maximum speed
    if new_fan_speed > 100:
        return 100 - fan_speed  # cap it at 100%
    elif new_fan_speed < MIN_FAN_SPEED:
        return MIN_FAN_SPEED - fan_speed  # jump to minimum fan speed
    return delta


def compute_fan_speed_delta(temp: float, temp_delta: float, fan_speed: float):
    if temp >= HOT:
        return get_increase_fan_speed_delta(fan_speed, 100.0)

    if temp <= COLD:
        # if temperature is decreasing, we slowly decrease the fan speed
        if temp_delta < 0.0:
            return get_decrease_fan_speed_delta(fan_speed, FAN_DELTA, turn_off=True)
        # if temperature is constant or increasing we don't change fan speed
        # until it rises above COLD
        return 0.0

    # if temperature is decreasing we decrease fan speed slowly
    if temp_delta < 0.0:
        return get_decrease_fan_speed_delta(fan_speed, FAN_DELTA, turn_off=False)

    # if temperature is increasing we increase fan speed slowly
    if temp_delta > 0.0:
        return get_increase_fan_speed_delta(fan_speed, FAN_DELTA)

    # if temperature is not changing, don't change the fan speed
    return 0.0