Source code for ui_utils

"""With no screen and no keypad, we have to make do with the buttons and LEDs.

The *ui_utils* module gives you the ability to enter data at program run-time.
This can reduce the number of times you have to edit and re-download your program.
This is especially handy if you are running your CodeBot untethered.

Attributes:
  UI_BUTTON_NONE (int): value used to represent NO BUTTON is pressed
  UI_BUTTON_0 (int) : value used to represent BTN-0 is pressed
  UI_BUTTON_1 (int) : value used to represent BTN-1 is pressed
  UI_BUTTON_BOTH (int) : value used to represent BOTH buttons are pressed

Treating "both buttons are pressed" as a special case gives us a virtual 3rd button.
"""

import botcore as cb
#import devbotcore as cb

import time

UI_BUTTON_NONE = 0x00
UI_BUTTON_0 = 0x01
UI_BUTTON_1 = 0x02
UI_BUTTON_BOTH = 0x03

def get_button():
    """Returns which button is currently pressed, as one of the UI_BUTTON_xxx codes."""
    result = UI_BUTTON_NONE
    if cb.buttons.is_pressed(0):
        result |= UI_BUTTON_0
    if cb.buttons.is_pressed(1):
        result |= UI_BUTTON_1
    if result == UI_BUTTON_NONE:
        return UI_BUTTON_NONE
    time.sleep(0.25) # TODO tune debounce
    result = 0
    if cb.buttons.is_pressed(0):
        result |= UI_BUTTON_0
    if cb.buttons.is_pressed(1):
        result |= UI_BUTTON_1
    while cb.buttons.is_pressed(0) or cb.buttons.is_pressed(1):
        time.sleep(0.1)
    time.sleep(0.1)
    return result

def wait_for_button(requested_ui_button):
    """Wait until the specified button is pressed.

       Args:
         requested_ui_button (int): the UI_BUTTON_XXX combination to wait for

    """
    while get_button() != requested_ui_button:
        pass

def tweak_parameter(initial_value):
    """Allows a value to be adjusted, or kept as-is:

         Press BTN-1 to raise the value.

         Press BTN-0 to lower the value.

         Press BOTH buttons at the same time to lock-in your choice.

         Flashes the final value on the LEDs so you can tell what you entered.

       Args:
         initial_value (int): the value to start at.
    """
    value = initial_value
    cb.leds.user(value)
    done = False
    while not done:
        button = get_button()
        if button == UI_BUTTON_BOTH:
            done = True
        elif button == UI_BUTTON_1:
            if value < 255:
                value += 1
        elif button == UI_BUTTON_0:
            if value > 0:
                value -= 1
        cb.leds.user(value)

    count = 3
    while count:
        count -= 1
        cb.leds.user(0)
        time.sleep(0.5)
        cb.leds.user(value)
        time.sleep(0.5)

    cb.leds.user(0)
    time.sleep(0.5)

    return value