/*
   language.c - Foreign language translation for PGP
   Finds foreign language "subtitles" for English phrases 
   in external foriegn language text file.

   (c) Copyright 1990-1996 by Philip Zimmermann.  All rights reserved.
   The author assumes no liability for damages resulting from the use
   of this software, even if the damage results from defects in this
   software.  No warranty is expressed or implied.

   Note that while most PGP source modules bear Philip Zimmermann's
   copyright notice, many of them have been revised or entirely written
   by contributors who frequently failed to put their names in their
   code.  Code that has been incorporated into PGP from other authors
   was either originally published in the public domain or is used with
   permission from the various authors.

   PGP is available for free to the public under certain restrictions.
   See the PGP User's Guide (included in the release package) for
   important information about licensing, patent restrictions on
   certain algorithms, trademarks, copyrights, and export controls.
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include "usuals.h"
#include "fileio.h"
#include "language.h"
#include "pgp.h"
#include "charset.h"
#include "armor.h"

#define SUBTITLES_FILE	"language.txt"
#define LANG_INDEXFILE	"language.idx"

#define	STRBUFSIZE		2048

char language[16] = "en";	/* The language code, defaults to English */
static char *strbuf;
static char lang[16];		/* readstr sets this to the language id of
				   the msg it last read */
static int subtitles_available = 0;
static int line = 0;
/*      subtitles_available is used to determine if we know whether the special
   subtitles_file exists.  subtitles_available has the following values:
   0  = first time thru, we don't yet know if subtitles_file exists.
   1  = we have already determined that subtitles_file exists.
   -1 = we have already determined that subtitles_file does not exist.
 */

#define	NEWLINE		0
#define	COMMENT		1
#define	INSTRING	2
#define	ESCAPE		3
#define	IDENT		4
#define	DONE		5
#define	ERROR		6
#define	ERR1		7

/* Look for and return a quoted string from the file.
 * If nlabort is true, return failure if we find a blank line
 * before we find the opening quote.
 */
static char *
 readstr(FILE * f, char *buf, int nlabort)
{
    int c, d;
    char *p = buf;
    int state = NEWLINE;
    int i = 0;

    while ((c = getc(f)) != EOF) {
	if (c == '\r')
	    continue;
	/* line numbers are only incremented when creating index file */
	if (line && c == '\n')
	    ++line;
	switch (state) {
	case NEWLINE:
	    switch (c) {
	    case '#':
		state = COMMENT;
		break;
	    case '"':
		state = INSTRING;
		break;
	    case '\n':
		if (nlabort) {
		    *buf = '\0';
		    return buf;
		}
	    default:
		if (i == 0 && isalnum(c)) {
		    state = IDENT;
		    lang[i++] = c;
		    break;
		}
		if (!isspace(c)) {
		    fprintf(stderr, "language.txt:%d: syntax error\n", line);
		    state = ERROR;
		}
	    }
	    break;
	case COMMENT:
	    if (c == '\n')
		state = NEWLINE;
	    break;
	case INSTRING:
	    switch (c) {
	    case '\\':
		state = ESCAPE;
		break;
	    case '"':
		state = DONE;
		break;
	    default:
		*p++ = c;
	    }
	    break;
	case ESCAPE:
	    switch (c) {
	    case 'n':
		*p++ = '\n';
		break;
	    case 'r':
		*p++ = '\r';
		break;
	    case 't':
		*p++ = '\t';
		break;
	    case 'e':
#ifdef EBCDIC
		*p++ = ESC;
#else
		*p++ = '\033';
#endif
		break;
	    case 'a':
#ifdef EBCDIC
		*p++ = '\a';
#else
		*p++ = '\007';
#endif
		break;
	    case '#':
	    case '"':
	    case '\\':
		*p++ = c;
		break;
	    case '\n':
		break;
	    case '0':
	    case '1':
	    case '2':
	    case '3':
	    case '4':
	    case '5':
	    case '6':
	    case '7':
		d = c - '0';
		while ((c = fgetc(f)) >= '0' && c <= '7')
		    d = 8 * d + c - '0';
#ifdef EBCDIC
/* dirty hack for \007 chars in LANG:    LANG("\n\007....")
   The right way is to replace all \007 by \a in the args of LANG() */
		if (d == 7) d = '\a';
#endif
		*p++ = d;
		ungetc(c, f);
		break;
	    default:
		fprintf(stderr,
			"language.txt:%d: illegal escape sequence: '\\%c'\n",
			line, c);
		break;
	    }
	    state = INSTRING;
	    break;
	case IDENT:		/* language identifier */
	    if (c == ':') {
		state = NEWLINE;
		break;
	    }
	    if (c == '\n' && strncmp(lang, "No translation", 14) == 0) {
		i = 0;
		state = NEWLINE;
		break;
	    }
	    lang[i++] = c;
	    if (i == 15 || !isalnum(c) && !isspace(c)) {
		lang[i] = '\0';
		fprintf(stderr,
			"language.txt:%d: bad language identifier: '%s'\n",
			line, lang);
		state = ERROR;
		i = 0;
	    }
	    break;
	case DONE:
	    if (c == '\n') {
		lang[i] = '\0';
		*p = '\0';
		return buf;
	    }
	    if (!isspace(c)) {
		fprintf(stderr,
			"language.txt:%d: extra characters after '\"'\n",
			line);
		state = ERROR;
	    }
	    break;
	case ERROR:
	    if (c == '\n')
		state = ERR1;
	    break;
	case ERR1:
	    state = (c == '\n' ? NEWLINE : ERROR);
	    break;
	}
    }
    if (state != NEWLINE)
	fprintf(stderr, "language.txt: unexpected EOF\n");
    return NULL;
}

#ifdef TEST
main()
{
    char buf[2048];

    line = 1;
    while (readstr(stdin, buf, 0)) {
	printf("\nen: <%s>\n", buf);
	while (readstr(stdin, buf, 1) && *buf != '\0')
	    printf("%s: <%s>\n", lang, buf);
    }
    exit(0);
}
#else

static struct indx_ent {
    word32 crc;
    long offset;
} *indx_tbl = NULL;

static int max_msgs = 0;
static long nmsg = 0;

static FILE *langf;

static void init_lang(void);

static int make_indexfile(char *);

/*
 * uses 24-bit CRC function from armor.c
 */
static word32
 message_crc(char *s)
{
    return crcbytes((byte *) s, strlen(s), (word32) 0);
}

/*
 * lookup file offset in indx_tbl
 */
static long lookup_offset(word32 crc)
{
    int i;

    for (i = 0; i < nmsg; ++i)
	if (indx_tbl[i].crc == crc)
	    return indx_tbl[i].offset;
    return -1;
}


/*
 * return foreign translation of s
 */
char *
 LANG(char *s)
{
    long filepos;
#ifdef MACTC5
	extern Boolean contains_yesNo, contains_enough, contains_badpass;
	contains_yesNo = (((void *) strstr(s, "(Y/n)?") != NULL) ||
	    ((void *) strstr(s, "(y/N)?") != NULL));
	contains_enough = ((void *) strstr(s, "Enough") != NULL);
	contains_badpass = (strstr(s, "Bad pass phrase.") != NULL);
#endif /* MACTC5 */
    if (subtitles_available == 0)
	init_lang();
    if (subtitles_available < 0)
	return s;

    filepos = lookup_offset(message_crc(s));
    if (filepos == -1) {
	return s;
    } else {
	fseek(langf, filepos, SEEK_SET);
	readstr(langf, strbuf, 1);
    }

    if (strbuf[0] == '\0')
	return s;

#ifndef EBCDIC /* no conversion for ebcdic printf() messages needed */
    for (s = strbuf; *s; ++s)
	*s = EXT_C(*s);
#endif
    return strbuf;
}


static struct {
    long lang_fsize;		/* size of language.txt */
    char lang[16];		/* language identifier */
    long nmsg;			/* number of messages */
} indx_hdr;


/*
 * initialize the index table: read it from language.idx or create
 * a new one and write it to the index file. A new index file is
 * created if the language set in config.pgp doesn't match the one
 * in language.idx or if the size of language.txt has changed.
 */
static void init_lang()
{
    char indexfile[MAX_PATH];
    char subtitles_file[MAX_PATH];
    FILE *indexf;
#ifdef PGP_SYSTEM_DIR 
    int use_system_wide_lang = 0; 
#endif 

    if (strcmp(language, "en") == 0) {
	subtitles_available = -1;
	return;			/* use default messages */
    }
    buildfilename(subtitles_file, SUBTITLES_FILE);
    langf = fopen(subtitles_file, FOPRBIN); /* Open file in binary mode... */
    if (langf == NULL) {
#ifdef PGP_SYSTEM_DIR
	strcpy(subtitles_file, PGP_SYSTEM_DIR);
	strcat(subtitles_file, SUBTITLES_FILE);
	langf = fopen(subtitles_file, FOPRBIN); /* Open file in binary mode... */
	use_system_wide_lang = 1;
	if (langf == NULL)
#endif
	{
	    subtitles_available = -1;
	    return;
	}
    }
    init_crc();
    strbuf = (char *) malloc(STRBUFSIZE);
    if (strbuf == NULL) {
	fprintf(stderr, "Not enough memory for foreign subtitles\n");
	fclose(langf);
	subtitles_available = -1;
	return;
    }
#ifdef PGP_SYSTEM_DIR
    if (use_system_wide_lang) {
	strcpy(indexfile, PGP_SYSTEM_DIR);
	strcat(indexfile, LANG_INDEXFILE);
    } else
#endif
    buildfilename(indexfile, LANG_INDEXFILE);
    indexf = fopen(indexfile, FOPRBIN);
    if (indexf != NULL) {
	if (fread(&indx_hdr, 1, sizeof(indx_hdr),
		  indexf) == sizeof(indx_hdr) &&
	    indx_hdr.lang_fsize == fsize(langf) &&
	    strcmp(indx_hdr.lang, language) == 0) {
	    nmsg = indx_hdr.nmsg;
	    indx_tbl = (struct indx_ent *) malloc(nmsg *
						  sizeof(struct indx_ent));
	    if (indx_tbl == NULL) {
		fprintf(stderr, "Not enough memory for foreign subtitles\n");
		fclose(indexf);
		fclose(langf);
		subtitles_available = -1;
		return;
	    }
	    if (fread(indx_tbl,
		      sizeof(struct indx_ent), nmsg, indexf) != nmsg) {
		free(indx_tbl);	/* create a new one */
		indx_tbl = NULL;
	    }
	}
	fclose(indexf);
    }
    if (indx_tbl == NULL && make_indexfile(indexfile) < 0) {
	fclose(langf);
	subtitles_available = -1;
    } else {
	subtitles_available = 1;
    }
}


static int make_indexfile(char *indexfile)
{
    FILE *indexf;
    long filepos;
    int total_msgs = 0;
    char *res;

    if (verbose)		/* must be set in config.pgp */
	fprintf(stderr,
		"Creating language index file '%s' for language \"%s\"\n",
		indexfile, language);
    rewind(langf);
    indx_hdr.lang_fsize = fsize(langf);
    strncpy(indx_hdr.lang, language, 15);
    init_crc();
    line = 1;
    nmsg = 0;
    while (readstr(langf, strbuf, 0)) {
	if (nmsg == max_msgs) {
	    if (max_msgs) {
		max_msgs *= 2;
		indx_tbl = (struct indx_ent *) realloc(indx_tbl, max_msgs *
						sizeof(struct indx_ent));
	    } else {
		max_msgs = 400;
		indx_tbl = (struct indx_ent *) malloc(max_msgs *
						sizeof(struct indx_ent));
	    }
	    if (indx_tbl == NULL) {
		fprintf(stderr, "Not enough memory for foreign subtitles\n");
		return -1;
	    }
	}
	++total_msgs;
	indx_tbl[nmsg].crc = message_crc(strbuf);
	if (lookup_offset(indx_tbl[nmsg].crc) != -1)
	    fprintf(stderr,
		    "language.txt:%d: Message CRC not unique: \"%s\"\n",
		    line, strbuf);
	do {
	    filepos = ftell(langf);
	    res = readstr(langf, strbuf, 1);	/* Abort if find newline
						   first */
	} while (res && strbuf[0] != '\0' && strcmp(language, lang) != 0);

	if (res == NULL)
	    break;
	if (strbuf[0] == '\0')	/* No translation */
	    continue;

	indx_tbl[nmsg].offset = filepos;
	++nmsg;
	do
	    res = readstr(langf, strbuf, 1);	/* Abort if find newline
						   first */
	while (res && strbuf[0] != '\0');
    }
    line = 0;
    indx_hdr.nmsg = nmsg;
    if (nmsg == 0) {
	fprintf(stderr, "No translations available for language \"%s\"\n\n",
		language);
	return -1;
    }
    if (verbose || total_msgs != nmsg)
	fprintf(stderr, "%d messages, %d translations\n\n", total_msgs, nmsg);

    if ((indexf = fopen(indexfile, FOPWBIN)) == NULL) {
	fprintf(stderr, "Cannot create %s\n", indexfile);
    } else {
	fwrite(&indx_hdr, 1, sizeof(indx_hdr), indexf);
	fwrite(indx_tbl, sizeof(struct indx_ent), nmsg, indexf);
	if (ferror(indexf) || fclose(indexf))
	    fprintf(stderr, "error writing %s\n", indexfile);
    }
    return 0;
}
#endif				/* TEST */