qmk_firmware/users/333fred/333fred.c

#include "333fred.h"
#include "quantum.h"
#include "action.h"

typedef enum {
    SINGLE_TAP, SINGLE_HOLD, DOUBLE
} tap_dance_state_enum;

static tap_dance_state_enum tap_dance_state;
static bool tap_dance_active = false;

void tap_dance_layer_finished(qk_tap_dance_state_t *state, void *user_data) {
    // Determine the current state
    if (state->count == 1) {
        if (state->interrupted || state->pressed == 0) tap_dance_state = SINGLE_TAP;
        else tap_dance_state = SINGLE_HOLD;
    } else {
        // Handle any number of other taps as a VIM movement hold
        tap_dance_state = DOUBLE;
    }

    switch (tap_dance_state) {
        case SINGLE_TAP:
            if (tap_dance_active) {
                reset_oneshot_layer();
                tap_dance_active = false;
            } else {
                set_oneshot_layer(SYMB, ONESHOT_START);
                tap_dance_active = true;
            }
            break;
        case SINGLE_HOLD:
            layer_on(SYMB);
            break;
        case DOUBLE:
            layer_on(VIM);
    }
}


void tap_dance_layer_reset(qk_tap_dance_state_t *state, void *user_data) {
    switch(tap_dance_state) {
        case SINGLE_TAP:
            clear_oneshot_layer_state(ONESHOT_PRESSED);
            break;
        case SINGLE_HOLD:
            layer_off(SYMB);
            break;
        case DOUBLE:
            layer_off(VIM);
            break;
    }
}

qk_tap_dance_action_t tap_dance_actions[] = {
    [TD_SYM_VIM] = ACTION_TAP_DANCE_FN_ADVANCED(NULL, tap_dance_layer_finished, tap_dance_layer_reset)
};

void tap_dance_process_record(uint16_t keycode) {
    if (tap_dance_state == SINGLE_TAP && keycode != TD(TD_SYM_VIM)) {
        tap_dance_active = false;
    }
}