/*      $OpenBSD: v_sentence.c,v 1.8 2022/12/26 19:16:04 jmc Exp $      */

/*-
 * Copyright (c) 1992, 1993, 1994
 *      The Regents of the University of California.  All rights reserved.
 * Copyright (c) 1992, 1993, 1994, 1995, 1996
 *      Keith Bostic.  All rights reserved.
 *
 * See the LICENSE file for redistribution information.
 */

#include "config.h"

#include <sys/types.h>
#include <sys/queue.h>
#include <sys/time.h>

#include <bitstring.h>
#include <ctype.h>
#include <limits.h>
#include <stdio.h>

#include "../common/common.h"
#include "vi.h"

/*
 * !!!
 * In historic vi, a sentence was delimited by a '.', '?' or '!' character
 * followed by TWO spaces or a newline.  One or more empty lines was also
 * treated as a separate sentence.  The Berkeley documentation for historical
 * vi states that any number of ')', ']', '"' and '\'' characters can be
 * between the delimiter character and the spaces or end of line, however,
 * the historical implementation did not handle additional '"' characters.
 * We follow the documentation here, not the implementation.
 *
 * Once again, historical vi didn't do sentence movements associated with
 * counts consistently, mostly in the presence of lines containing only
 * white-space characters.
 *
 * This implementation also permits a single tab to delimit sentences, and
 * treats lines containing only white-space characters as empty lines.
 * Finally, tabs are eaten (along with spaces) when skipping to the start
 * of the text following a "sentence".
 */

/*
 * v_sentencef -- [count])
 *      Move forward count sentences.
 *
 * PUBLIC: int v_sentencef(SCR *, VICMD *);
 */
int
v_sentencef(SCR *sp, VICMD *vp)
{
        enum { BLANK, NONE, PERIOD } state;
        VCS cs;
        size_t len;
        u_long cnt;

        cs.cs_lno = vp->m_start.lno;
        cs.cs_cno = vp->m_start.cno;
        if (cs_init(sp, &cs))
                return (1);

        cnt = F_ISSET(vp, VC_C1SET) ? vp->count : 1;

        /*
         * !!!
         * If in white-space, the next start of sentence counts as one.
         * This may not handle "  .  " correctly, but it's real unclear
         * what correctly means in that case.
         */
        if (cs.cs_flags == CS_EMP || (cs.cs_flags == 0 && isblank(cs.cs_ch))) {
                if (cs_fblank(sp, &cs))
                        return (1);
                if (--cnt == 0) {
                        if (vp->m_start.lno != cs.cs_lno ||
                            vp->m_start.cno != cs.cs_cno)
                                goto okret;
                        return (1);
                }
        }

        for (state = NONE;;) {
                if (cs_next(sp, &cs))
                        return (1);
                if (cs.cs_flags == CS_EOF)
                        break;
                if (cs.cs_flags == CS_EOL) {
                        if ((state == PERIOD || state == BLANK) && --cnt == 0) {
                                if (cs_next(sp, &cs))
                                        return (1);
                                if (cs.cs_flags == 0 &&
                                    isblank(cs.cs_ch) && cs_fblank(sp, &cs))
                                        return (1);
                                goto okret;
                        }
                        state = NONE;
                        continue;
                }
                if (cs.cs_flags == CS_EMP) {    /* An EMP is two sentences. */
                        if (--cnt == 0)
                                goto okret;
                        if (cs_fblank(sp, &cs))
                                return (1);
                        if (--cnt == 0)
                                goto okret;
                        state = NONE;
                        continue;
                }
                switch (cs.cs_ch) {
                case '.':
                case '?':
                case '!':
                        state = PERIOD;
                        break;
                case ')':
                case ']':
                case '"':
                case '\'':
                        if (state != PERIOD)
                                state = NONE;
                        break;
                case '\t':
                        if (state == PERIOD)
                                state = BLANK;
                        /* FALLTHROUGH */
                case ' ':
                        if (state == PERIOD) {
                                state = BLANK;
                                break;
                        }
                        if (state == BLANK && --cnt == 0) {
                                if (cs_fblank(sp, &cs))
                                        return (1);
                                goto okret;
                        }
                        /* FALLTHROUGH */
                default:
                        state = NONE;
                        break;
                }
        }

        /* EOF is a movement sink, but it's an error not to have moved. */
        if (vp->m_start.lno == cs.cs_lno && vp->m_start.cno == cs.cs_cno) {
                v_eof(sp, NULL);
                return (1);
        }

okret:  vp->m_stop.lno = cs.cs_lno;
        vp->m_stop.cno = cs.cs_cno;

        /*
         * !!!
         * Historic, uh, features, yeah, that's right, call 'em features.
         * If the starting and ending cursor positions are at the first
         * column in their lines, i.e. the movement is cutting entire lines,
         * the buffer is in line mode, and the ending position is the last
         * character of the previous line.  Note check to make sure that
         * it's not within a single line.
         *
         * Non-motion commands move to the end of the range.  Delete and
         * yank stay at the start.  Ignore others.  Adjust the end of the
         * range for motion commands.
         */
        if (ISMOTION(vp)) {
                if (vp->m_start.cno == 0 &&
                    (cs.cs_flags != 0 || vp->m_stop.cno == 0)) {
                        if (vp->m_start.lno < vp->m_stop.lno) {
                                if (db_get(sp,
                                    --vp->m_stop.lno, DBG_FATAL, NULL, &len))
                                        return (1);
                                vp->m_stop.cno = len ? len - 1 : 0;
                        }
                        F_SET(vp, VM_LMODE);
                } else
                        --vp->m_stop.cno;
                vp->m_final = vp->m_start;
        } else
                vp->m_final = vp->m_stop;
        return (0);
}

/*
 * v_sentenceb -- [count](
 *      Move backward count sentences.
 *
 * PUBLIC: int v_sentenceb(SCR *, VICMD *);
 */
int
v_sentenceb(SCR *sp, VICMD *vp)
{
        VCS cs;
        recno_t slno;
        size_t len, scno;
        u_long cnt;
        int last;

        /*
         * !!!
         * Historic vi permitted the user to hit SOF repeatedly.
         */
        if (vp->m_start.lno == 1 && vp->m_start.cno == 0)
                return (0);

        cs.cs_lno = vp->m_start.lno;
        cs.cs_cno = vp->m_start.cno;
        if (cs_init(sp, &cs))
                return (1);

        cnt = F_ISSET(vp, VC_C1SET) ? vp->count : 1;

        /*
         * !!!
         * In empty lines, skip to the previous non-white-space character.
         * If in text, skip to the previous white-space character.  Believe
         * it or not, in the paragraph:
         *      ab cd.
         *      AB CD.
         * if the cursor is on the 'A' or 'B', ( moves to the 'a'.  If it
         * is on the ' ', 'C' or 'D', it moves to the 'A'.  Yes, Virginia,
         * Berkeley was once a major center of drug activity.
         */
        if (cs.cs_flags == CS_EMP) {
                if (cs_bblank(sp, &cs))
                        return (1);
                for (;;) {
                        if (cs_prev(sp, &cs))
                                return (1);
                        if (cs.cs_flags != CS_EOL)
                                break;
                }
        } else if (cs.cs_flags == 0 && !isblank(cs.cs_ch))
                for (;;) {
                        if (cs_prev(sp, &cs))
                                return (1);
                        if (cs.cs_flags != 0 || isblank(cs.cs_ch))
                                break;
                }

        for (last = 0;;) {
                if (cs_prev(sp, &cs))
                        return (1);
                if (cs.cs_flags == CS_SOF)      /* SOF is a movement sink. */
                        break;
                if (cs.cs_flags == CS_EOL) {
                        last = 1;
                        continue;
                }
                if (cs.cs_flags == CS_EMP) {
                        if (--cnt == 0)
                                goto ret;
                        if (cs_bblank(sp, &cs))
                                return (1);
                        last = 0;
                        continue;
                }
                switch (cs.cs_ch) {
                case '.':
                case '?':
                case '!':
                        if (!last || --cnt != 0) {
                                last = 0;
                                continue;
                        }

ret:                    slno = cs.cs_lno;
                        scno = cs.cs_cno;

                        /*
                         * Move to the start of the sentence, skipping blanks
                         * and special characters.
                         */
                        do {
                                if (cs_next(sp, &cs))
                                        return (1);
                        } while (!cs.cs_flags &&
                            (cs.cs_ch == ')' || cs.cs_ch == ']' ||
                            cs.cs_ch == '"' || cs.cs_ch == '\''));
                        if ((cs.cs_flags || isblank(cs.cs_ch)) &&
                            cs_fblank(sp, &cs))
                                return (1);

                        /*
                         * If it was ".  xyz", with the cursor on the 'x', or
                         * "end.  ", with the cursor in the spaces, or the
                         * beginning of a sentence preceded by an empty line,
                         * we can end up where we started.  Fix it.
                         */
                        if (vp->m_start.lno != cs.cs_lno ||
                            vp->m_start.cno != cs.cs_cno)
                                goto okret;

                        /*
                         * Well, if an empty line preceded possible blanks
                         * and the sentence, it could be a real sentence.
                         */
                        for (;;) {
                                if (cs_prev(sp, &cs))
                                        return (1);
                                if (cs.cs_flags == CS_EOL)
                                        continue;
                                if (cs.cs_flags == 0 && isblank(cs.cs_ch))
                                        continue;
                                break;
                        }
                        if (cs.cs_flags == CS_EMP)
                                goto okret;

                        /* But it wasn't; try again. */
                        ++cnt;
                        cs.cs_lno = slno;
                        cs.cs_cno = scno;
                        last = 0;
                        break;
                case '\t':
                        last = 1;
                        break;
                default:
                        last =
                            cs.cs_flags == CS_EOL || isblank(cs.cs_ch) ||
                            cs.cs_ch == ')' || cs.cs_ch == ']' ||
                            cs.cs_ch == '"' || cs.cs_ch == '\'' ? 1 : 0;
                }
        }

okret:  vp->m_stop.lno = cs.cs_lno;
        vp->m_stop.cno = cs.cs_cno;

        /*
         * !!!
         * If the starting and stopping cursor positions are at the first
         * columns in the line, i.e. the movement is cutting an entire line,
         * the buffer is in line mode, and the starting position is the last
         * character of the previous line.
         *
         * All commands move to the end of the range.  Adjust the start of
         * the range for motion commands.
         */
        if (ISMOTION(vp)) {
                if (vp->m_start.cno == 0 &&
                    (cs.cs_flags != 0 || vp->m_stop.cno == 0)) {
                        if (db_get(sp,
                            --vp->m_start.lno, DBG_FATAL, NULL, &len))
                                return (1);
                        vp->m_start.cno = len ? len - 1 : 0;
                        F_SET(vp, VM_LMODE);
                } else
                        --vp->m_start.cno;
        }
        vp->m_final = vp->m_stop;
        return (0);
}