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/*-
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 * Copyright (c) 1992, 1993
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 *        The Regents of the University of California.  All rights reserved.
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 *
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 * This code is derived from software contributed to Berkeley by
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 * Chris Torek and Darren F. Provine.
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 *
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 * Redistribution and use in source and binary forms, with or without
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 * modification, are permitted provided that the following conditions
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 * are met:
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 * 1. Redistributions of source code must retain the above copyright
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 *    notice, this list of conditions and the following disclaimer.
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 * 2. Redistributions in binary form must reproduce the above copyright
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 *    notice, this list of conditions and the following disclaimer in the
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 *    documentation and/or other materials provided with the distribution.
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 * 3. Neither the name of the University nor the names of its contributors
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 *    may be used to endorse or promote products derived from this software
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 *    without specific prior written permission.
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 *
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 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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 * SUCH DAMAGE.
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 *
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 *        @(#)input.c        8.1 (Berkeley) 5/31/93
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 */
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/* Modified for Prex by Kohsuke Ohtani. */
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/*
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 * Tetris input.
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 */
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#include <sys/types.h>
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#include <sys/time.h>
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#include <sys/termios.h>
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#include <sys/prex.h>
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#include <errno.h>
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#include <unistd.h>
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#include "input.h"
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#include "tetris.h"
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/* return true if the given timeval is positive */
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#define        TV_POS(tv) \
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        ((tv)->tv_sec > 0 || ((tv)->tv_sec == 0 && (tv)->tv_usec > 0))
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/* subtract timeval `sub' from `res' */
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#define        TV_SUB(res, sub) \
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        (res)->tv_sec -= (sub)->tv_sec; \
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        (res)->tv_usec -= (sub)->tv_usec; \
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        if ((res)->tv_usec < 0) { \
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                (res)->tv_usec += 1000000; \
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                (res)->tv_sec--; \
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        }
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/*
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 * Do a `read wait': select for reading from stdin, with timeout *tvp.
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 * On return, modify *tvp to reflect the amount of time spent waiting.
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 * It will be positive only if input appeared before the time ran out;
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 * otherwise it will be zero or perhaps negative.
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 *
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 * If tvp is nil, wait forever, but return if select is interrupted.
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 *
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 * Return 0 => no input, 1 => can read() from stdin
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 */
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int
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rwait(struct timeval *tvp)
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{
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        int i, ninq, timeout;
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        struct timeval starttv, endtv;
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#define        NILTZ ((struct timezone *)0)
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        if (tvp) {
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                (void) gettimeofday(&starttv, NILTZ);
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                endtv = *tvp;
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                timeout = tvp->tv_usec / 1000;
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        } else
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                timeout = 1000;
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        /*
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         * We don't have select() or poll() as for now.
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         * This is replaced by polling TTY input queue via ioctl().
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         */
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        for (i = 0; i < timeout; i++) {
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                ioctl(1, TIOCINQ, &ninq);
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                if (ninq > 0)
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                        break;
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                timer_sleep(1, 0);        /* wait 1ms */
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        }
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        if (i >= timeout) {        /* timed out */
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                if (tvp == NULL)
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                        return (-1);
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                else {
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                        tvp->tv_sec = 0;
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                        tvp->tv_usec = 0;
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                        return (0);
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                }
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        }
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        if (tvp) {
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                /* since there is input, we may not have timed out */
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                (void) gettimeofday(&endtv, NILTZ);
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                TV_SUB(&endtv, &starttv);
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                TV_SUB(tvp, &endtv);        /* adjust *tvp by elapsed time */
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        }
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        return (1);
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}
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/*
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 * `sleep' for the current turn time (using select).
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 * Eat any input that might be available.
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 */
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void
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tsleep(void)
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{
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        struct timeval tv;
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        char c;
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        tv.tv_sec = 0;
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        tv.tv_usec = fallrate;
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        while (TV_POS(&tv))
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                if (rwait(&tv) && read(0, &c, 1) != 1)
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                        break;
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}
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/*
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 * Eat up any input (used at end of game).
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 */
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void
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eat_input(void)
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{
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        struct timeval tv;
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        char c;
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        do {
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                tv.tv_sec = tv.tv_usec = 0;
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        } while (rwait(&tv) && read(0, &c, 1) == 1);
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}
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/*
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 * getchar with timeout.
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 */
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int
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tgetchar(void)
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{
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        static struct timeval timeleft;
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        char c;
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        /*
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         * Reset timeleft to fallrate whenever it is not positive.
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         * In any case, wait to see if there is any input.  If so,
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         * take it, and update timeleft so that the next call to
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         * tgetchar() will not wait as long.  If there is no input,
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         * make timeleft zero or negative, and return -1.
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         *
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         * Most of the hard work is done by rwait().
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         */
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        if (!TV_POS(&timeleft)) {
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                faster();        /* go faster */
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                timeleft.tv_sec = 0;
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                timeleft.tv_usec = fallrate;
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        }
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        if (!rwait(&timeleft))
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                return (-1);
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        if (read(0, &c, 1) != 1)
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                stop("end of file, help");
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        return ((int)(unsigned char)c);
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}