/* tap-list.c - list every event tap in the current login session.
 *
 * Copyright (c) 2026 Lazy Developers
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 *
 * Build:  cc -framework ApplicationServices -o tap-list tap-list.c
 * Run:    ./tap-list
 *
 * CGGetEventTapList is a public Core Graphics API. It reads the list of taps
 * the window server holds for this session - process id, the mask of event
 * types the tap subscribed to, its options and whether it is enabled - and
 * needs no Accessibility, Input Monitoring or Screen Recording permission.
 * This program only reads; it opens no tap of its own and touches no event.
 *
 * The keyboard event types are bits 10, 11 and 12 (key down, key up, modifier
 * flags changed), together 0x1c00. A tap whose mask has none of them never
 * receives a keystroke. */
#include <ApplicationServices/ApplicationServices.h>
#include <libproc.h>
#include <stdio.h>

#define KEYBOARD_BITS ((CGEventMask)0x1c00)

int main(void) {
    uint32_t count = 0;
    CGError err = CGGetEventTapList(0, NULL, &count);
    if (err != kCGErrorSuccess) { fprintf(stderr, "CGGetEventTapList: error %d\n", (int)err); return 1; }
    CGEventTapInformation taps[256];
    if (count > 256) count = 256;
    err = CGGetEventTapList(count, taps, &count);
    if (err != kCGErrorSuccess) { fprintf(stderr, "CGGetEventTapList: error %d\n", (int)err); return 1; }
    printf("%u event tap(s) in this session\n", (unsigned)count);
    for (uint32_t i = 0; i < count; i++) {
        char name[2 * MAXCOMLEN + 1] = "?";
        proc_name((int)taps[i].tappingProcess, name, sizeof name);
        printf("pid=%-6d %-32s mask=0x%-10llx options=%d enabled=%d keyboard=%s\n",
            (int)taps[i].tappingProcess, name, (unsigned long long)taps[i].eventsOfInterest,
            (int)taps[i].options, taps[i].enabled ? 1 : 0,
            (taps[i].eventsOfInterest & KEYBOARD_BITS) ? "YES" : "no");
    }
    return 0;
}