// Copyright 2021-2022 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 custom_shift_keys.c
 * @brief Custom Shift Keys implementation
 *
 * For full documentation, see
 * <https://getreuer.info/posts/keyboards/custom-shift-keys>
 */

#include "custom_shift_keys.h"

bool process_custom_shift_keys(uint16_t keycode, keyrecord_t *record) {
    static uint16_t registered_keycode = KC_NO;

    // If a custom shift key is registered, then this event is either releasing
    // it or manipulating another key at the same time. Either way, we release
    // the currently registered key.
    if (registered_keycode != KC_NO)
        {
         unregister_code16(registered_keycode);
         registered_keycode = KC_NO;
        }

    if (record->event.pressed)
    {  // Press event.
        const uint8_t mods = get_mods();

#ifndef NO_ACTION_ONESHOT
    if ((mods | get_weak_mods() | get_oneshot_mods()) & MOD_MASK_SHIFT)
    {
#else
    if ((mods | get_weak_mods()) & MOD_MASK_SHIFT)
        {  // Shift is held.
#endif  // NO_ACTION_ONESHOT
            // Search for a custom key with keycode equal to `keycode`.
            for (int i = 0; i < NUM_CUSTOM_SHIFT_KEYS; ++i)
            {

                if (keycode == custom_shift_keys[i].keycode)
                {
                    // Continue default handling if this is a tap-hold key being held.
                    if (((QK_MOD_TAP <= keycode && keycode <= QK_MOD_TAP_MAX) || (QK_LAYER_TAP <= keycode && keycode <= QK_LAYER_TAP_MAX)) && record->tap.count == 0)
                    {
                        return true;
                    }

#ifndef NO_ACTION_ONESHOT
                del_oneshot_mods(MOD_MASK_SHIFT);
#endif  // NO_ACTION_ONESHOT
                del_mods(MOD_MASK_SHIFT);
                del_weak_mods(MOD_MASK_SHIFT);
                send_keyboard_report();
                registered_keycode = custom_shift_keys[i].shifted_keycode;
                register_code16(registered_keycode);
                set_mods(mods);  // Restore the mods.
                return false;
                }
            }
        }
    }

  return true;  // Continue with default handling.
}