/*
 *  R : A Computer Language for Statistical Data Analysis
 *  Copyright (C) 2001-3   The R Development Core Team.
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include <Defn.h>
#include <Rconnections.h>
#ifdef USE_SYSTEM_REGEX
# include <regex.h>
#else
# include "Rregex.h"
#endif

static SEXP allocMatrixNA(SEXPTYPE, int, int);
static void transferVector(SEXP s, SEXP t);

SEXP do_readDCF(SEXP call, SEXP op, SEXP args, SEXP env)
{
    int nwhat, nret, nc, nr, m, k, lastm, need, skip;
    int whatlen, dynwhat, buflen=0;
    char *line, *buf;
    regex_t blankline, contline, trailblank, regline;
    regmatch_t regmatch[1];
    SEXP file, what, what2, retval, retval2, dims, dimnames;
    Rconnection con=NULL;
    Rboolean wasopen;

    checkArity(op, args);

    file = CAR(args);
    con = getConnection(asInteger(file));
    if(!con->canread)
        error("cannot read from this connection");
    wasopen = con->isopen;
    if(!wasopen)
	if(!con->open(con)) error("cannot open the connection");

    PROTECT(what = coerceVector(CADR(args), STRSXP));
    nwhat = LENGTH(what);
    dynwhat = (nwhat==0);

    line = (char *) malloc(MAXELTSIZE);
    if(!line)
	error("Could not allocate memory for read.dcf");
    buflen = 100;
    buf = (char *) malloc(buflen);
    if(!buf)
	error("Could not allocate memory for read.dcf");
    nret = 20;
    /* it is easier if we first have a record per column */
    PROTECT (retval = allocMatrixNA(STRSXP, LENGTH(what), nret));

    regcomp(&blankline, "^[[:blank:]]*$", REG_NOSUB & REG_EXTENDED);
    regcomp(&trailblank, "[[:blank:]]+$", REG_EXTENDED);
    regcomp(&contline, "^[[:blank:]]+", REG_EXTENDED);
    regcomp(&regline, "^[^:]+:[[:blank:]]*", REG_EXTENDED);

    k=0;
    lastm=-1;
    skip=1;
    while(Rconn_getline(con, line, MAXELTSIZE) >= 0){
	if(strlen(line)==0 || regexec(&blankline, line, 0, 0, 0)==0){
	    if(skip==0){
		k++;
		if(k>nret-1){
		    nret *= 2;
		    PROTECT(retval2 = allocMatrixNA(STRSXP, LENGTH(what), nret));
		    transferVector(retval2, retval);
		    UNPROTECT_PTR(retval);
		    retval = retval2;
		}
	    }
	    skip=1;
	}
	else{
	    skip=0;
	    /* remove trailing whitespace */
	    if(regexec(&trailblank, line, 1, regmatch, 0)==0){
		line[regmatch[0].rm_so] = '\0';
	    }

	    if(lastm>=0 && regexec(&contline, line, 1, regmatch,
				   0)==0){
		need = strlen(line+regmatch[0].rm_eo) +
		    strlen(CHAR(STRING_ELT(retval, lastm+nwhat*k)))+2;
		if(buflen < need) {
		    buf = (char *) realloc(buf, need);
		    if(!buf)
			error("Could not allocate memory for read.dcf");
		    buflen = need;
		}
		strcpy(buf,CHAR(STRING_ELT(retval, lastm+nwhat*k)));
		strcat(buf, "\n");
		strcat(buf, line+regmatch[0].rm_eo);
		SET_STRING_ELT(retval, lastm+nwhat*k, mkChar(buf));
	    }
	    else{
		if(regexec(&regline, line, 1, regmatch, 0)==0){
		    for(m=0; m<nwhat; m++){
			whatlen = strlen(CHAR(STRING_ELT(what, m)));
			if(line[whatlen]==':' &&
			   strncmp(CHAR(STRING_ELT(what, m)),
				   line, whatlen) == 0){
			    SET_STRING_ELT(retval, m+nwhat*k,
					   mkChar(line +
						  regmatch[0].rm_eo));
			    lastm=m;
			    break;
			}
			else{
			    lastm = -1;
			}
		    }
		    if(dynwhat && (lastm == -1)){
			PROTECT(what2 = allocVector(STRSXP, nwhat+1));
			PROTECT(retval2 = allocMatrixNA(STRSXP,
					      nrows(retval)+1,
					      ncols(retval)));
			if(nwhat>0){
			    copyVector(what2, what);
			    for(nr=0; nr<nrows(retval); nr++){
				for(nc=0; nc<ncols(retval); nc++){
				    SET_STRING_ELT(retval2,
						   nr+nc*nrows(retval2),
						   STRING_ELT(retval,
							      nr+nc*nrows(retval)));
				}
			    }
			}
			UNPROTECT_PTR(retval);
			UNPROTECT_PTR(what);
			retval = retval2;
			what=what2;
			need = strlen(line+regmatch[0].rm_eo);
			if(buflen < need){
			    buf = (char *) realloc(buf, need);
			    if(!buf)
				error("Could not allocate memory for read.dcf");
			    buflen = need;
			}
			strncpy(buf, line, strchr(line, ':')-line);
			buf[strchr(line, ':')-line] = '\0';
			SET_STRING_ELT(what, nwhat, mkChar(buf));
			nwhat++;
			/* lastm uses C indexing, hence nwhat-1 */
			lastm=nwhat-1;
			SET_STRING_ELT(retval, lastm+nwhat*k,
				       mkChar(line +
					      regmatch[0].rm_eo));
		    }
		}
		else{
		  /* error("Line %d is malformed!", n+1); */
		}
	    }
	}
    }
    if(!wasopen) con->close(con);
    free(line);
    free(buf);
    regfree(&blankline);
    regfree(&contline);
    regfree(&trailblank);
    regfree(&regline);

    if(skip==0) k++;

    /* and now transpose the whole matrix */
    PROTECT(retval2 = allocMatrixNA(STRSXP, k, LENGTH(what)));
    copyMatrix(retval2, retval, 1);

    PROTECT(dimnames = allocVector(VECSXP, 2));
    PROTECT(dims = allocVector(INTSXP, 2));
    INTEGER(dims)[0] = k;
    INTEGER(dims)[1] = LENGTH(what);
    SET_VECTOR_ELT(dimnames, 1, what);
    setAttrib(retval2, R_DimSymbol, dims);
    setAttrib(retval2, R_DimNamesSymbol, dimnames);
    UNPROTECT(5);
    return(retval2);
}


static SEXP allocMatrixNA(SEXPTYPE mode, int nrow, int ncol)
{
    int k;
    SEXP retval;

    PROTECT(retval=allocMatrix(mode, nrow, ncol));
    for(k=0;k<LENGTH(retval);k++){
	SET_STRING_ELT(retval, k, NA_STRING);
    }
    UNPROTECT(1);
    return(retval);
}

/* This one is needed because the normal copy operations will do
   recycling */

static void transferVector(SEXP s, SEXP t)
{
    int i, ns, nt;

    nt = LENGTH(t);
    ns = LENGTH(s);
    for (i = 0; i < nt; i++)
	SET_STRING_ELT(s, i, STRING_ELT(t, i));
}