// Copyright 2022-2023 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

/**
 * @file layer_lock.c
 * @brief Layer Lock implementation
 *
 * For full documentation, see
 * <https://getreuer.info/posts/keyboards/layer-lock>
 */

#include "layer_lock.h"
#include "process_layer_lock.h"
#include "quantum_keycodes.h"
#include "action_util.h"

// The current lock state. The kth bit is on if layer k is locked.
extern layer_state_t locked_layers;
#if defined(LAYER_LOCK_IDLE_TIMEOUT) && LAYER_LOCK_IDLE_TIMEOUT > 0
extern uint32_t layer_lock_timer;
#endif

// Handles an event on an `MO` or `TT` layer switch key.
static bool handle_mo_or_tt(uint8_t layer, keyrecord_t* record) {
    if (is_layer_locked(layer)) {
        if (record->event.pressed) { // On press, unlock the layer.
            layer_lock_invert(layer);
        }
        return false; // Skip default handling.
    }
    return true;
}

bool process_layer_lock(uint16_t keycode, keyrecord_t* record) {
#ifndef NO_ACTION_LAYER
#    if defined(LAYER_LOCK_IDLE_TIMEOUT) && LAYER_LOCK_IDLE_TIMEOUT > 0
    layer_lock_timer = timer_read32();
#    endif // LAYER_LOCK_IDLE_TIMEOUT > 0

    // The intention is that locked layers remain on. If something outside of
    // this feature turned any locked layers off, unlock them.
    if ((locked_layers & ~layer_state) != 0) {
        layer_lock_set_kb(locked_layers &= layer_state);
    }

    if (keycode == QK_LAYER_LOCK) {
        if (record->event.pressed) { // The layer lock key was pressed.
            layer_lock_invert(get_highest_layer(layer_state));
        }
        return false;
    }

    switch (keycode) {
        case QK_MOMENTARY ... QK_MOMENTARY_MAX: // `MO(layer)` keys.
            return handle_mo_or_tt(QK_MOMENTARY_GET_LAYER(keycode), record);

        case QK_LAYER_TAP_TOGGLE ... QK_LAYER_TAP_TOGGLE_MAX: // `TT(layer)`.
            return handle_mo_or_tt(QK_LAYER_TAP_TOGGLE_GET_LAYER(keycode), record);

        case QK_LAYER_MOD ... QK_LAYER_MOD_MAX: { // `LM(layer, mod)`.
            uint8_t layer = QK_LAYER_MOD_GET_LAYER(keycode);
            if (is_layer_locked(layer)) {
                if (record->event.pressed) { // On press, unlock the layer.
                    layer_lock_invert(layer);
                } else { // On release, clear the mods.
                    clear_mods();
                    send_keyboard_report();
                }
                return false; // Skip default handling.
            }
        } break;

#    ifndef NO_ACTION_TAPPING
        case QK_LAYER_TAP ... QK_LAYER_TAP_MAX: // `LT(layer, key)` keys.
            if (record->tap.count == 0 && !record->event.pressed && is_layer_locked(QK_LAYER_TAP_GET_LAYER(keycode))) {
                // Release event on a held layer-tap key where the layer is locked.
                return false; // Skip default handling so that layer stays on.
            }
            break;
#    endif // NO_ACTION_TAPPING
    }
#endif // NO_ACTION_LAYER
    return true;
}