from kmk.kmktime import ticks_diff, ticks_ms


def df_pressed(key, state, *args, **kwargs):
    '''
    Switches the default layer
    '''
    state._active_layers[-1] = key.meta.layer
    return state


def mo_pressed(key, state, *args, **kwargs):
    '''
    Momentarily activates layer, switches off when you let go
    '''
    state._active_layers.insert(0, key.meta.layer)
    return state


def mo_released(key, state, KC, *args, **kwargs):
    # remove the first instance of the target layer
    # from the active list
    # under almost all normal use cases, this will
    # disable the layer (but preserve it if it was triggered
    # as a default layer, etc.)
    # this also resolves an issue where using DF() on a layer
    # triggered by MO() and then defaulting to the MO()'s layer
    # would result in no layers active
    try:
        del_idx = state._active_layers.index(key.meta.layer)
        del state._active_layers[del_idx]
    except ValueError:
        pass

    return state


def lm_pressed(key, state, *args, **kwargs):
    '''
    As MO(layer) but with mod active
    '''
    state._hid_pending = True
    # Sets the timer start and acts like MO otherwise
    state._start_time['lm'] = ticks_ms()
    state._keys_pressed.add(key.meta.kc)
    return mo_pressed(key, state, *args, **kwargs)


def lm_released(key, state, *args, **kwargs):
    '''
    As MO(layer) but with mod active
    '''
    state._hid_pending = True
    state._keys_pressed.discard(key.meta.kc)
    state._start_time['lm'] = None
    return mo_released(key, state, *args, **kwargs)


def lt_pressed(key, state, *args, **kwargs):
    # Sets the timer start and acts like MO otherwise
    state._start_time['lt'] = ticks_ms()
    return mo_pressed(key, state, *args, **kwargs)


def lt_released(key, state, *args, **kwargs):
    # On keyup, check timer, and press key if needed.
    if state._start_time['lt'] and (
        ticks_diff(ticks_ms(), state._start_time['lt']) < state.tap_time
    ):
        state._hid_pending = True
        state._tap_key(key.meta.kc)

    mo_released(key, state, *args, **kwargs)
    state._start_time['lt'] = None
    return state


def tg_pressed(key, state, *args, **kwargs):
    '''
    Toggles the layer (enables it if not active, and vise versa)
    '''
    # See mo_released for implementation details around this
    try:
        del_idx = state._active_layers.index(key.meta.layer)
        del state._active_layers[del_idx]
    except ValueError:
        state._active_layers.insert(0, key.meta.layer)

    return state


def to_pressed(key, state, *args, **kwargs):
    '''
    Activates layer and deactivates all other layers
    '''
    state._active_layers.clear()
    state._active_layers.insert(0, key.meta.layer)

    return state


def tt_pressed(key, state, *args, **kwargs):
    '''
    Momentarily activates layer if held, toggles it if tapped repeatedly
    '''
    # TODO Make this work with tap dance to function more correctly, but technically works.
    if state._start_time['tt'] is None:
        # Sets the timer start and acts like MO otherwise
        state._start_time['tt'] = ticks_ms()
        return mo_pressed(key, state, *args, **kwargs)
    elif ticks_diff(ticks_ms(), state._start_time['tt']) < state.tap_time:
        state._start_time['tt'] = None
        return tg_pressed(key, state, *args, **kwargs)


def tt_released(key, state, *args, **kwargs):
    tap_timed_out = ticks_diff(ticks_ms(), state._start_time['tt']) >= state.tap_time
    if state._start_time['tt'] is None or tap_timed_out:
        # On first press, works like MO. On second press, does nothing unless let up within
        # time window, then acts like TG.
        state._start_time['tt'] = None
        return mo_released(key, state, *args, **kwargs)

    return state