/*
 * The functions in this file implement commands that search in the forward
 * and backward directions. There are no special characters in the search
 * strings. Probably should have a regular expression search, or something
 * like that.
 *
 */

#include        <stdio.h>
#include	"estruct.h"
#include        "edef.h"

/*
 * Search forward. Get a search string from the user, and search, beginning at
 * ".", for the string. If found, reset the "." to be just after the match
 * string, and [perhaps] repaint the display. Bound to "C-S".
 */

/*	string search input parameters	*/

#define	PTBEG	1	/* leave the point at the begining on search */
#define	PTEND	2	/* leave the point at the end on search */

forwsearch(f, n)

{
	register int status;

	/* resolve the repeat count */
	if (n == 0)
		n = 1;
	if (n < 1)	/* search backwards */
		return(backsearch(f, -n));

	/* ask the user for the text of a pattern */
	if ((status = readpattern("Search")) != TRUE)
		return(status);

	/* search for the pattern */
	while (n-- > 0) {
		if ((status = forscan(&pat[0],PTEND)) == FALSE)
			break;
	}

	/* and complain if not there */
	if (status == FALSE)
		mlwrite("Not found");
	return(status);
}

forwhunt(f, n)

{
	register int status;

	/* resolve the repeat count */
	if (n == 0)
		n = 1;
	if (n < 1)	/* search backwards */
		return(backhunt(f, -n));

	/* Make sure a pattern exists */
	if (pat[0] == 0) {
		mlwrite("No pattern set");
		return(FALSE);
	}

	/* search for the pattern */
	while (n-- > 0) {
		if ((status = forscan(&pat[0],PTEND)) == FALSE)
			break;
	}

	/* and complain if not there */
	if (status == FALSE)
		mlwrite("Not found");
	return(status);
}

/*
 * Reverse search. Get a search string from the user, and search, starting at
 * "." and proceeding toward the front of the buffer. If found "." is left
 * pointing at the first character of the pattern [the last character that was
 * matched]. Bound to "C-R".
 */
backsearch(f, n)

{
	register int s;

	/* resolve null and negative arguments */
	if (n == 0)
		n = 1;
	if (n < 1)
		return(forwsearch(f, -n));

	/* get a pattern to search */
	if ((s = readpattern("Reverse search")) != TRUE)
		return(s);

	/* and go search for it */
	bsearch(f,n);
}

backhunt(f, n)	/* hunt backward for the last search string entered */

{
	/* resolve null and negative arguments */
	if (n == 0)
		n = 1;
	if (n < 1)
		return(forwhunt(f, -n));

	/* Make sure a pattern exists */
	if (pat[0] == 0) {
		mlwrite("No pattern set");
		return(FALSE);
	}

	/* and go search for it */
	bsearch(f,n);
}

bsearch(f, n)

{
	register LINE *clp;
	register int cbo;
	register LINE *tlp;
	register int tbo;
	register int c;
	register char *epp;
	register char *pp;

	/* find a pointer to the end of the pattern */
	for (epp = &pat[0]; epp[1] != 0; ++epp)
		;

	/* make local copies of the starting location */
	clp = curwp->w_dotp;
	cbo = curwp->w_doto;

	while (n-- > 0) {
		for (;;) {
			/* if we are at the begining of the line, wrap back around */
			if (cbo == 0) {
				clp = lback(clp);

				if (clp == curbp->b_linep) {
					mlwrite("Not found");
					return(FALSE);
				}

				cbo = llength(clp)+1;
			}

			/* fake the <NL> at the end of a line */
			if (--cbo == llength(clp))
				c = '\n';
			else
				c = lgetc(clp, cbo);

			/* check for a match against the end of the pattern */
			if (eq(c, *epp) != FALSE) {
				tlp = clp;
				tbo = cbo;
				pp  = epp;

				/* scanning backwards through the rest of the
				   pattern looking for a match			*/
				while (pp != &pat[0]) {
					/* wrap across a line break */
					if (tbo == 0) {
						tlp = lback(tlp);
						if (tlp == curbp->b_linep)
							goto fail;

						tbo = llength(tlp)+1;
					}

					/* fake the <NL> */
					if (--tbo == llength(tlp))
						c = '\n';
					else
						c = lgetc(tlp, tbo);

					if (eq(c, *--pp) == FALSE)
						goto fail;
				}

				/* A Match!  reset the current cursor */
				curwp->w_dotp  = tlp;
				curwp->w_doto  = tbo;
				curwp->w_flag |= WFMOVE;
				goto next;
			}
fail:;
		}
next:;
	}
	return(TRUE);
}

/*
 * Compare two characters. The "bc" comes from the buffer. It has it's case
 * folded out. The "pc" is from the pattern.
 */
eq(bc, pc)
	int bc;
	int pc;

{
	if ((curwp->w_bufp->b_mode & MDEXACT) == 0) {
		if (bc>='a' && bc<='z')
			bc -= 0x20;

		if (pc>='a' && pc<='z')
			pc -= 0x20;
	}

	if (bc == pc)
		return(TRUE);

	return(FALSE);
}

/*
 * Read a pattern. Stash it in the external variable "pat". The "pat" is not
 * updated if the user types in an empty line. If the user typed an empty line,
 * and there is no old pattern, it is an error. Display the old pattern, in the
 * style of Jeff Lomicka. There is some do-it-yourself control expansion.
 * change to using <ESC> to delemit the end-of-pattern to allow <NL>s in
 * the search string.
 */
readpattern(prompt)

char *prompt;

{
	register int s;
	char tpat[NPAT+20];

	strcpy(tpat, prompt);	/* copy prompt to output string */
	strcat(tpat, " [");	/* build new prompt string */
	expandp(&pat[0], &tpat[strlen(tpat)], NPAT/2);	/* add old pattern */
	strcat(tpat, "]<ESC>: ");

	s = mlreplyt(tpat, tpat, NPAT, 27);	/* Read pattern */

	if (s == TRUE)				/* Specified */
		strcpy(pat, tpat);
	else if (s == FALSE && pat[0] != 0)	/* CR, but old one */
		s = TRUE;

	return(s);
}

sreplace(f, n)	/*	Search and replace (ESC-R)	*/

int f;		/* default flag */
int n;		/* # of repetitions wanted */

{
	return(replaces(FALSE, f, n));
}

qreplace(f, n)	/*	search and replace with query (ESC-CTRL-R)	*/

int f;		/* default flag */
int n;		/* # of repetitions wanted */

{
	return(replaces(TRUE, f, n));
}

/*	replaces:	search for a string and replace it with another
			string. query might be enabled (according to
			kind).						*/
replaces(kind, f, n)

int kind;	/* Query enabled flag */
int f;		/* default flag */
int n;		/* # of repetitions wanted */

{
	register int i;		/* loop index */
	register int s;		/* success flag on pattern inputs */
	register int slength,
		     rlength;	/* length of search and replace strings */
	register int numsub;	/* number of substitutions */
	register int nummatch;	/* number of found matches */
	int nlflag;		/* last char of search string a <NL>? */
	int nlrepl;		/* was a replace done on the last line? */
	char tmpc;		/* temporary character */
	char c;			/* input char for query */
	char tpat[NPAT];	/* temporary to hold search pattern */
	LINE *origline;		/* original "." position */
	int origoff;		/* and offset (for . query option) */

	if (curbp->b_mode&MDVIEW)	/* don't allow this command if	*/
		return(rdonly());	/* we are in read only mode	*/

	/* check for negative repititions */
	if (f && n < 0)
		return(FALSE);

	/* ask the user for the text of a pattern */
	if ((s = readpattern(
		(kind == FALSE ? "Replace" : "Query replace"))) != TRUE)
		return(s);
	strcpy(&tpat[0], &pat[0]);	/* salt it away */

	/* ask for the replacement string */
	strcpy(&pat[0], &rpat[0]);	/* set up default string */
	if ((s = readpattern("with")) == ABORT)
		return(s);

	/* move everything to the right place and length them */
	strcpy(&rpat[0], &pat[0]);
	strcpy(&pat[0], &tpat[0]);
	slength = strlen(&pat[0]);
	rlength = strlen(&rpat[0]);

	/* set up flags so we can make sure not to do a recursive
	   replace on the last line */
	nlflag = (pat[slength - 1] == '\n');
	nlrepl = FALSE;

	/* build query replace question string */
	strcpy(tpat, "Replace '");
	expandp(&pat[0], &tpat[strlen(tpat)], NPAT/3);
	strcat(tpat, "' with '");
	expandp(&rpat[0], &tpat[strlen(tpat)], NPAT/3);
	strcat(tpat, "'? ");

	/* save original . position */
	origline = curwp->w_dotp;
	origoff = curwp->w_doto;

	/* scan through the file */
	numsub = 0;
	nummatch = 0;
	while ((f == FALSE || n > nummatch) &&
		(nlflag == FALSE || nlrepl == FALSE)) {

		/* search for the pattern */
		if (forscan(&pat[0],PTBEG) != TRUE)
			break;		/* all done */
		++nummatch;	/* increment # of matches */

		/* check if we are on the last line */
		nlrepl = (lforw(curwp->w_dotp) == curwp->w_bufp->b_linep);
		
		/* check for query */
		if (kind) {
			/* get the query */
			mlwrite(&tpat[0], &pat[0], &rpat[0]);
qprompt:
			update();  /* show the proposed place to change */
			c = (*term.t_getchar)();	/* and input */
			mlwrite("");			/* and clear it */

			/* and respond appropriately */
			switch (c) {
				case 'y':	/* yes, substitute */
				case ' ':
						break;

				case 'n':	/* no, onword */
						forwchar(FALSE, 1);
						continue;

				case '!':	/* yes/stop asking */
						kind = FALSE;
						break;

				case '.':	/* abort! and return */
						/* restore old position */
						curwp->w_dotp = origline;
						curwp->w_doto = origoff;
						curwp->w_flag |= WFMOVE;

				case BELL:	/* abort! and stay */
						mlwrite("Aborted!");
						return(FALSE);

				default:	/* bitch and beep */
						(*term.t_beep)();

				case '?':	/* help me */
mlwrite("(Y)es, (N)o, (!)Do the rest, (^G)Abort, (.)Abort back, (?)Help: ");
						goto qprompt;

			}
		}

		/* delete the sucker */
		if (ldelete(slength, FALSE) != TRUE) {
			/* error while deleting */
			mlwrite("ERROR while deleteing");
			return(FALSE);
		}

		/* and insert its replacement */
		for (i=0; i<rlength; i++) {
			tmpc = rpat[i];
			s = (tmpc == '\n' ? lnewline() : linsert(1, tmpc));
			if (s != TRUE) {
				/* error while inserting */
				mlwrite("Out of memory while inserting");
				return(FALSE);
			}
		}

		numsub++;	/* increment # of substitutions */
	}

	/* and report the results */
	mlwrite("%d substitutions",numsub);
	return(TRUE);
}

forscan(patrn,leavep)	/*	search forward for a <patrn>	*/

char *patrn;		/* string to scan for */
int leavep;		/* place to leave point
				PTBEG = begining of match
				PTEND = at end of match		*/

{
	register LINE *curline;		/* current line during scan */
	register int curoff;		/* position within current line */
	register LINE *lastline;	/* last line position during scan */
	register int lastoff;		/* position within last line */
	register int c;			/* character at current position */
	register LINE *matchline;	/* current line during matching */
	register int matchoff;		/* position in matching line */
	register char *patptr;		/* pointer into pattern */

	/* setup local scan pointers to global "." */

	curline = curwp->w_dotp;
	curoff = curwp->w_doto;

	/* scan each character until we hit the head link record */

	while (curline != curbp->b_linep) {

		/* save the current position in case we need to
		   restore it on a match			*/

		lastline = curline;
		lastoff = curoff;

		/* get the current character resolving EOLs */

		if (curoff == llength(curline)) {	/* if at EOL */
			curline = lforw(curline);	/* skip to next line */
			curoff = 0;
			c = '\n';			/* and return a <NL> */
		} else
			c = lgetc(curline, curoff++);	/* get the char */

		/* test it against first char in pattern */
		if (eq(c, patrn[0]) != FALSE) {	/* if we find it..*/
			/* setup match pointers */
			matchline = curline;
			matchoff = curoff;
			patptr = &patrn[0];

			/* scan through patrn for a match */
			while (*++patptr != 0) {
				/* advance all the pointers */
				if (matchoff == llength(matchline)) {
					/* advance past EOL */
					matchline = lforw(matchline);
					matchoff = 0;
					c = '\n';
				} else
					c = lgetc(matchline, matchoff++);

				/* and test it against the pattern */
				if (eq(*patptr, c) == FALSE)
					goto fail;
			}

			/* A SUCCESSFULL MATCH!!! */
			/* reset the global "." pointers */
			if (leavep == PTEND) {	/* at end of string */
				curwp->w_dotp = matchline;
				curwp->w_doto = matchoff;
			} else {		/* at begining of string */
				curwp->w_dotp = lastline;
				curwp->w_doto = lastoff;
			}
			curwp->w_flag |= WFMOVE; /* flag that we have moved */
			return(TRUE);

		}
fail:;			/* continue to search */
	}

	/* we could not find a match */

	return(FALSE);
}

/* 	expandp:	expand control key sequences for output		*/

expandp(srcstr, deststr, maxlength)

char *srcstr;	/* string to expand */
char *deststr;	/* destination of expanded string */
int maxlength;	/* maximum chars in destination */

{
	char c;		/* current char to translate */

	/* scan through the string */
	while ((c = *srcstr++) != 0) {
		if (c == '\n') {		/* its an EOL */
			*deststr++ = '<';
			*deststr++ = 'N';
			*deststr++ = 'L';
			*deststr++ = '>';
			maxlength -= 4;
		} else if (c < 0x20 || c == 0x7f) {	/* control character */
			*deststr++ = '^';
			*deststr++ = c ^ 0x40;
			maxlength -= 2;
		} else if (c == '%') {
			*deststr++ = '%';
			*deststr++ = '%';
			maxlength -= 2;

		} else {			/* any other character */
			*deststr++ = c;
			maxlength--;
		}

		/* check for maxlength */
		if (maxlength < 4) {
			*deststr++ = '$';
			*deststr = '\0';
			return(FALSE);
		}
	}
	*deststr = '\0';
	return(TRUE);
}