/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 1980, 1992, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */



#include <sys/select.h>
#include <sys/time.h>

#include <errno.h>
#include <ctype.h>
#include <stdlib.h>
#include <termios.h>
#include <unistd.h>

#include "systat.h"
#include "extern.h"

static char line[80];
static int keyboard_dispatch(int ch);

int
keyboard(void)
{
        int ch, n;
        struct timeval last, intvl, now, tm;
        fd_set rfds;

        /* Set initial timings */
        gettimeofday(&last, NULL);
        intvl.tv_sec = delay / 1000000;
        intvl.tv_usec = delay % 1000000;
        for (;;) {
                col = 0;
                move(CMDLINE, 0);
                for (;;) {
                        /* Determine interval to sleep */
                        (void)gettimeofday(&now, NULL);
                        tm.tv_sec = last.tv_sec + intvl.tv_sec - now.tv_sec;
                        tm.tv_usec = last.tv_usec + intvl.tv_usec - now.tv_usec;
                        while (tm.tv_usec < 0) {
                                tm.tv_usec += 1000000;
                                tm.tv_sec--;
                        }
                        while (tm.tv_usec >= 1000000) {
                                tm.tv_usec -= 1000000;
                                tm.tv_sec++;
                        }
                        if (tm.tv_sec < 0) {
                                /* We have to update screen immediately */
                                display();
                                gettimeofday(&last, NULL);
                                continue;
                        }

                        /* Prepare select  */
                        FD_ZERO(&rfds);
                        FD_SET(STDIN_FILENO, &rfds);
                        n = select(STDIN_FILENO + 1, &rfds, NULL, NULL, &tm);

                        if (n > 0) {
                                /* Read event on stdin */
                                ch = getch();

                                if (keyboard_dispatch(ch) == 0) {
                                        refresh();
                                        continue;
                                }
        
                                line[col] = '\0';
                                command(line + 1);
                                /* Refresh delay */
                                intvl.tv_sec = delay / 1000000;
                                intvl.tv_usec = delay % 1000000;
                                refresh();
                                break;
                        }

                        if (n < 0 && errno != EINTR)
                                exit(1);

                        /* Timeout or signal. Call display another time */
                        display();
                        gettimeofday(&last, NULL);
                }
        }
}

static int
keyboard_dispatch(int ch)
{

        if (ch == ERR) {
                if (errno == EINTR)
                        return 0;
                exit(1);
        }
        if (ch >= 'A' && ch <= 'Z')
                ch += 'a' - 'A';
        if (col == 0) {
                if (ch == CTRL('l')) {
                        wrefresh(curscr);
                        return 0;
                }
                if (ch == CTRL('g')) {
                        status();
                        return 0;
                }
                if (ch != ':')
                        return 0;
                move(CMDLINE, 0);
                clrtoeol();
        }
        if (ch == erasechar() && col > 0) {
                if (col == 1 && line[0] == ':')
                        return 0;
                col--;
                goto doerase;
        }
        if (ch == CTRL('w') && col > 0) {
                while (--col >= 0 && isspace(line[col]))
                        ;
                col++;
                while (--col >= 0 && !isspace(line[col]))
                        if (col == 0 && line[0] == ':')
                                return 1;
                col++;
                goto doerase;
        }
        if (ch == killchar() && col > 0) {
                col = 0;
                if (line[0] == ':')
                        col++;
doerase:
                move(CMDLINE, col);
                clrtoeol();
                return 0;
        }
        if (isprint(ch) || ch == ' ') {
                line[col] = ch;
                mvaddch(CMDLINE, col, ch);
                col++;
        }

        if (col == 0 || (ch != '\r' && ch != '\n'))
                return 0;

        return 1;
}