/*      $OpenBSD: screen.c,v 1.19 2019/06/28 13:32:52 deraadt Exp $     */
/*      $NetBSD: screen.c,v 1.4 1995/04/29 01:11:36 mycroft Exp $       */

/*-
 * Copyright (c) 1992, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Chris Torek and Darren F. Provine.
 *
 * 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.
 *
 *      @(#)screen.c    8.1 (Berkeley) 5/31/93
 */

/*
 * Tetris screen control.
 */

#include <sys/ioctl.h>

#include <err.h>
#include <setjmp.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <term.h>
#include <unistd.h>

#include "screen.h"
#include "tetris.h"

static cell curscreen[B_SIZE];  /* 1 => standout (or otherwise marked) */
static int curscore;
static int isset;               /* true => terminal is in game mode */
static struct termios oldtt;
static void (*tstp)(int);

static void     scr_stop(int);
static void     stopset(int);

/*
 * Capabilities from TERMCAP.
 */
extern char     PC, *BC, *UP;           /* tgoto requires globals: ugh! */

static char
        *bcstr,                 /* backspace char */
        *CEstr,                 /* clear to end of line */
        *CLstr,                 /* clear screen */
        *CMstr,                 /* cursor motion string */
#ifdef unneeded
        *CRstr,                 /* "\r" equivalent */
#endif
        *HOstr,                 /* cursor home */
        *LLstr,                 /* last line, first column */
        *pcstr,                 /* pad character */
        *TEstr,                 /* end cursor motion mode */
        *TIstr,                 /* begin cursor motion mode */
        *VIstr,                 /* make cursor invisible */
        *VEstr;                 /* make cursor appear normal */
char
        *SEstr,                 /* end standout mode */
        *SOstr;                 /* begin standout mode */
static int
        COnum,                  /* co# value */
        LInum,                  /* li# value */
        MSflag;                 /* can move in standout mode */


struct tcsinfo {                /* termcap string info; some abbrevs above */
        char tcname[3];
        char **tcaddr;
} tcstrings[] = {
        {"bc", &bcstr},
        {"ce", &CEstr},
        {"cl", &CLstr},
        {"cm", &CMstr},
#ifdef unneeded
        {"cr", &CRstr},
#endif
        {"le", &BC},            /* move cursor left one space */
        {"pc", &pcstr},
        {"se", &SEstr},
        {"so", &SOstr},
        {"te", &TEstr},
        {"ti", &TIstr},
        {"vi", &VIstr},
        {"ve", &VEstr},
        {"up", &UP},            /* cursor up */
        { {0}, NULL}
};

/* This is where we will actually stuff the information */

static char combuf[1024], tbuf[1024];


/*
 * Routine used by tputs().
 */
int
put(int c)
{

        return (putchar(c));
}

/*
 * putstr() is for unpadded strings (either as in termcap(5) or
 * simply literal strings); putpad() is for padded strings with
 * count=1.  (See screen.h for putpad().)
 */
#define putstr(s)       (void)fputs(s, stdout)
#define moveto(r, c)    putpad(tgoto(CMstr, c, r))

/*
 * Set up from termcap.
 */
void
scr_init(void)
{
        static int bsflag, xsflag, sgnum;
#ifdef unneeded
        static int ncflag;
#endif
        char *term, *fill;
        static struct tcninfo { /* termcap numeric and flag info */
                char tcname[3];
                int *tcaddr;
        } tcflags[] = {
                {"bs", &bsflag},
                {"ms", &MSflag},
#ifdef unneeded
                {"nc", &ncflag},
#endif
                {"xs", &xsflag},
                { {0}, NULL}
        }, tcnums[] = {
                {"co", &COnum},
                {"li", &LInum},
                {"sg", &sgnum},
                { {0}, NULL}
        };
        
        if ((term = getenv("TERM")) == NULL)
                stop("you must set the TERM environment variable");
        if (tgetent(tbuf, term) <= 0)
                stop("cannot find your termcap");
        fill = combuf;
        {
                struct tcsinfo *p;

                for (p = tcstrings; p->tcaddr; p++)
                        *p->tcaddr = tgetstr(p->tcname, &fill);
        }
        if (classic)
                SOstr = SEstr = NULL;
        {
                struct tcninfo *p;

                for (p = tcflags; p->tcaddr; p++)
                        *p->tcaddr = tgetflag(p->tcname);
                for (p = tcnums; p->tcaddr; p++)
                        *p->tcaddr = tgetnum(p->tcname);
        }
        if (bsflag)
                BC = "\b";
        else if (BC == NULL && bcstr != NULL)
                BC = bcstr;
        if (CLstr == NULL)
                stop("cannot clear screen");
        if (CMstr == NULL || UP == NULL || BC == NULL)
                stop("cannot do random cursor positioning via tgoto()");
        PC = pcstr ? *pcstr : 0;
        if (sgnum > 0 || xsflag)
                SOstr = SEstr = NULL;
#ifdef unneeded
        if (ncflag)
                CRstr = NULL;
        else if (CRstr == NULL)
                CRstr = "\r";
#endif
}

/* this foolery is needed to modify tty state `atomically' */
static jmp_buf scr_onstop;

static void
stopset(int sig)
{
        sigset_t sigset;

        (void) signal(sig, SIG_DFL);
        (void) kill(getpid(), sig);
        sigemptyset(&sigset);
        sigaddset(&sigset, sig);
        (void) sigprocmask(SIG_UNBLOCK, &sigset, (sigset_t *)0);
        longjmp(scr_onstop, 1);
}

static void
scr_stop(int sig)
{
        sigset_t sigset;

        scr_end();
        (void) kill(getpid(), sig);
        sigemptyset(&sigset);
        sigaddset(&sigset, sig);
        (void) sigprocmask(SIG_UNBLOCK, &sigset, (sigset_t *)0);
        scr_set();
        scr_msg(key_msg, 1);
}

/*
 * Set up screen mode.
 */
void
scr_set(void)
{
        struct winsize ws;
        struct termios newtt;
        sigset_t sigset, osigset;
        void (*ttou)(int);

        sigemptyset(&sigset);
        sigaddset(&sigset, SIGTSTP);
        sigaddset(&sigset, SIGTTOU);
        (void) sigprocmask(SIG_BLOCK, &sigset, &osigset);
        if ((tstp = signal(SIGTSTP, stopset)) == SIG_IGN)
                (void) signal(SIGTSTP, SIG_IGN);
        if ((ttou = signal(SIGTTOU, stopset)) == SIG_IGN)
                (void) signal(SIGTTOU, SIG_IGN);
        /*
         * At last, we are ready to modify the tty state.  If
         * we stop while at it, stopset() above will longjmp back
         * to the setjmp here and we will start over.
         */
        (void) setjmp(scr_onstop);
        (void) sigprocmask(SIG_SETMASK, &osigset, (sigset_t *)0);
        Rows = 0, Cols = 0;
        if (ioctl(0, TIOCGWINSZ, &ws) == 0) {
                Rows = ws.ws_row;
                Cols = ws.ws_col;
        }
        if (Rows == 0)
                Rows = LInum;
        if (Cols == 0)
        Cols = COnum;
        if (Rows < MINROWS || Cols < MINCOLS) {
                char smallscr[55];

                (void)snprintf(smallscr, sizeof(smallscr),
                    "the screen is too small (must be at least %dx%d)",
                    MINROWS, MINCOLS);
                stop(smallscr);
        }
        if (tcgetattr(0, &oldtt) == -1)
                stop("tcgetattr() fails");
        newtt = oldtt;
        newtt.c_lflag &= ~(ICANON|ECHO);
        newtt.c_oflag &= ~OXTABS;
        if (tcsetattr(0, TCSADRAIN, &newtt) == -1)
                stop("tcsetattr() fails");
        (void) sigprocmask(SIG_BLOCK, &sigset, &osigset);

        /*
         * We made it.  We are now in screen mode, modulo TIstr
         * (which we will fix immediately).
         */
        if (TIstr)
                putstr(TIstr);  /* termcap(5) says this is not padded */
        if (VIstr)
                putstr(VIstr);  /* termcap(5) says this is not padded */
        if (tstp != SIG_IGN)
                (void) signal(SIGTSTP, scr_stop);
        if (ttou != SIG_IGN)
                (void) signal(SIGTTOU, ttou);

        isset = 1;
        (void) sigprocmask(SIG_SETMASK, &osigset, (sigset_t *)0);
        scr_clear();
}

/*
 * End screen mode.
 */
void
scr_end(void)
{
        sigset_t sigset, osigset;

        sigemptyset(&sigset);
        sigaddset(&sigset, SIGTSTP);
        sigaddset(&sigset, SIGTTOU);
        (void) sigprocmask(SIG_BLOCK, &sigset, &osigset);
        /* move cursor to last line */
        if (LLstr)
                putstr(LLstr);  /* termcap(5) says this is not padded */
        else
                moveto(Rows - 1, 0);
        /* exit screen mode */
        if (TEstr)
                putstr(TEstr);  /* termcap(5) says this is not padded */
        if (VEstr)
                putstr(VEstr);  /* termcap(5) says this is not padded */
        (void) fflush(stdout);
        (void) tcsetattr(0, TCSADRAIN, &oldtt);
        isset = 0;
        /* restore signals */
        (void) signal(SIGTSTP, tstp);
        (void) sigprocmask(SIG_SETMASK, &osigset, (sigset_t *)0);
}

void
stop(char *why)
{

        if (isset)
                scr_end();
        errx(1, "aborting: %s", why);
}

/*
 * Clear the screen, forgetting the current contents in the process.
 */
void
scr_clear(void)
{

        putpad(CLstr);
        curscore = -1;
        memset((char *)curscreen, 0, sizeof(curscreen));
}

typedef cell regcell;

/*
 * Update the screen.
 */
void
scr_update(void)
{
        cell *bp, *sp;
        regcell so, cur_so = 0;
        int i, ccol, j;
        sigset_t sigset, osigset;
        static const struct shape *lastshape;

        sigemptyset(&sigset);
        sigaddset(&sigset, SIGTSTP);
        (void) sigprocmask(SIG_BLOCK, &sigset, &osigset);

        /* always leave cursor after last displayed point */
        curscreen[D_LAST * B_COLS - 1] = -1;

        if (score != curscore) {
                if (HOstr)
                        putpad(HOstr);
                else
                        moveto(0, 0);
                (void) printf("Score: %d", score);
                curscore = score;
        }

        /* draw preview of next pattern */
        if (showpreview && (nextshape != lastshape)) {
                static int r=5, c=2;
                int tr, tc, t;

                lastshape = nextshape;

                /* clean */
                putpad(SEstr);
                moveto(r-1, c-1); putstr("          ");
                moveto(r,   c-1); putstr("          ");
                moveto(r+1, c-1); putstr("          ");
                moveto(r+2, c-1); putstr("          ");

                moveto(r-3, c-2);
                putstr("Next shape:");

                /* draw */
                if (SOstr)
                        putpad(SOstr);
                moveto(r, 2 * c);
                putstr(SOstr ? "  " : "[]");
                for (i = 0; i < 3; i++) {
                        t = c + r * B_COLS;
                        t += nextshape->off[i];

                        tr = t / B_COLS;
                        tc = t % B_COLS;

                        moveto(tr, 2*tc);
                        putstr(SOstr ? "  " : "[]");
                }
                putpad(SEstr);
        }

        bp = &board[D_FIRST * B_COLS];
        sp = &curscreen[D_FIRST * B_COLS];
        for (j = D_FIRST; j < D_LAST; j++) {
                ccol = -1;
                for (i = 0; i < B_COLS; bp++, sp++, i++) {
                        if (*sp == (so = *bp))
                                continue;
                        *sp = so;
                        if (i != ccol) {
                                if (cur_so && MSflag) {
                                        putpad(SEstr);
                                        cur_so = 0;
                                }
                                moveto(RTOD(j), CTOD(i));
                        }
                        if (SOstr) {
                                if (so != cur_so) {
                                        putpad(so ? SOstr : SEstr);
                                        cur_so = so;
                                }
                                putstr("  ");
                        } else
                                putstr(so ? "[]" : "  ");
                        ccol = i + 1;
                        /*
                         * Look ahead a bit, to avoid extra motion if
                         * we will be redrawing the cell after the next.
                         * Motion probably takes four or more characters,
                         * so we save even if we rewrite two cells
                         * `unnecessarily'.  Skip it all, though, if
                         * the next cell is a different color.
                         */
#define STOP (B_COLS - 3)
                        if (i > STOP || sp[1] != bp[1] || so != bp[1])
                                continue;
                        if (sp[2] != bp[2])
                                sp[1] = -1;
                        else if (i < STOP && so == bp[2] && sp[3] != bp[3]) {
                                sp[2] = -1;
                                sp[1] = -1;
                        }
                }
        }
        if (cur_so)
                putpad(SEstr);
        (void) fflush(stdout);
        (void) sigprocmask(SIG_SETMASK, &osigset, (sigset_t *)0);
}

/*
 * Write a message (set!=0), or clear the same message (set==0).
 * (We need its length in case we have to overwrite with blanks.)
 */
void
scr_msg(char *s, int set)
{
        
        if (set || CEstr == NULL) {
                int l = strlen(s);

                moveto(Rows - 2, ((Cols - l) >> 1) - 1);
                if (set)
                        putstr(s);
                else
                        while (--l >= 0)
                                (void) putchar(' ');
        } else {
                moveto(Rows - 2, 0);
                putpad(CEstr);
        }
}