/* vi: set sw=4 ts=4: */
/*
 * shows keys pressed. inspired by kbd package
 *
 * Copyright (C) 2008 by Vladimir Dronnikov <dronnikov@gmail.com>
 *
 * Licensed under GPLv2, see file LICENSE in this source tree.
 */
//config:config SHOWKEY
//config:       bool "showkey (4.7 kb)"
//config:       default y
//config:       select PLATFORM_LINUX
//config:       help
//config:       Shows keys pressed.

//applet:IF_SHOWKEY(APPLET(showkey, BB_DIR_USR_BIN, BB_SUID_DROP))

//kbuild:lib-$(CONFIG_SHOWKEY) += showkey.o

//usage:#define showkey_trivial_usage
//usage:       "[-a | -k | -s]"
//usage:#define showkey_full_usage "\n\n"
//usage:       "Show keys pressed\n"
//usage:     "\n        -a      Display decimal/octal/hex values of the keys"
//usage:     "\n        -k      Display interpreted keycodes (default)"
//usage:     "\n        -s      Display raw scan-codes"

#include "libbb.h"
#include <linux/kd.h>


struct globals {
        int kbmode;
        struct termios tio, tio0;
};
#define G (*ptr_to_globals)
#define kbmode (G.kbmode)
#define tio    (G.tio)
#define tio0   (G.tio0)
#define INIT_G() do { \
        SET_PTR_TO_GLOBALS(xzalloc(sizeof(G))); \
} while (0)


// set raw tty mode
// also used by microcom
// libbb candidates?
static void xget1(struct termios *t, struct termios *oldt)
{
        tcgetattr(STDIN_FILENO, oldt);
        *t = *oldt;
        cfmakeraw(t);
}

static void xset1(struct termios *t)
{
        int ret = tcsetattr(STDIN_FILENO, TCSAFLUSH, t);
        if (ret) {
                bb_perror_msg("can't tcsetattr for stdin");
        }
}

int showkey_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int showkey_main(int argc UNUSED_PARAM, char **argv)
{
        enum {
                OPT_a = (1<<0), // display the decimal/octal/hex values of the keys
                OPT_k = (1<<1), // display only the interpreted keycodes (default)
                OPT_s = (1<<2), // display only the raw scan-codes
        };

        INIT_G();

        // FIXME: aks are all mutually exclusive
        getopt32(argv, "aks");

        // prepare for raw mode
        xget1(&tio, &tio0);
        // put stdin in raw mode
        xset1(&tio);

#define press_keys "Press any keys, program terminates %s:\r\n\n"

        if (option_mask32 & OPT_a) {
                // just read stdin char by char
                unsigned char c;

                printf(press_keys, "on EOF (ctrl-D)");

                // read and show byte values
                while (1 == read(STDIN_FILENO, &c, 1)) {
                        printf("%3u 0%03o 0x%02x\r\n", c, c, c);
                        if (04 /*CTRL-D*/ == c)
                                break;
                }
        } else {
                // we assume a PC keyboard
                xioctl(STDIN_FILENO, KDGKBMODE, &kbmode);
                printf("Keyboard mode was %s.\r\n\n",
                        kbmode == K_RAW ? "RAW" :
                                (kbmode == K_XLATE ? "XLATE" :
                                        (kbmode == K_MEDIUMRAW ? "MEDIUMRAW" :
                                                (kbmode == K_UNICODE ? "UNICODE" : "UNKNOWN")))
                );

                // set raw keyboard mode
                xioctl(STDIN_FILENO, KDSKBMODE, (void *)(ptrdiff_t)((option_mask32 & OPT_k) ? K_MEDIUMRAW : K_RAW));

                // we should exit on any signal; signals should interrupt read
                bb_signals_recursive_norestart(BB_FATAL_SIGS, record_signo);

                // inform user that program ends after time of inactivity
                printf(press_keys, "10s after last keypress");

                // read and show scancodes
                while (!bb_got_signal) {
                        char buf[18];
                        int i, n;

                        // setup 10s watchdog
                        alarm(10);

                        // read scancodes
                        n = read(STDIN_FILENO, buf, sizeof(buf));
                        i = 0;
                        while (i < n) {
                                if (option_mask32 & OPT_s) {
                                        // show raw scancodes
                                        printf("0x%02x ", buf[i++]);
                                } else {
                                        // show interpreted scancodes (default)
                                        char c = buf[i];
                                        int kc;
                                        if (i+2 < n
                                         && (c & 0x7f) == 0
                                         && (buf[i+1] & 0x80) != 0
                                         && (buf[i+2] & 0x80) != 0
                                        ) {
                                                kc = ((buf[i+1] & 0x7f) << 7) | (buf[i+2] & 0x7f);
                                                i += 3;
                                        } else {
                                                kc = (c & 0x7f);
                                                i++;
                                        }
                                        printf("keycode %3u %s", kc, (c & 0x80) ? "release" : "press");
                                }
                        }
                        puts("\r");
                }

                // restore keyboard mode
                xioctl(STDIN_FILENO, KDSKBMODE, (void *)(ptrdiff_t)kbmode);
        }

        // restore console settings
        xset1(&tio0);

        return EXIT_SUCCESS;
}