/*
  LibRCD - Statistic generator

  Copyright (C) 2005-2018 Suren A. Chilingaryan <csa@suren.me>

  This library is free software; you can redistribute it and/or modify it
  under the terms of the GNU Lesser General Public License version 2.1 or later
  as published by the Free Software Foundation.

  This library 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 Lesser General Public License 
  for more details.

  You should have received a copy of the GNU Lesser General Public License 
  along with this program; if not, write to the Free Software Foundation, Inc.,
  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/

#include <stdio.h>
#include <unistd.h>
#include <ctype.h>
#include <locale.h>
#include <math.h>
#include <iconv.h>
#include <langinfo.h>
#include <sys/types.h>
#include <sys/stat.h>

#define first_char 128
#define last_char 255

#define original_first_char 192
#define original_last_char 255

#define chars_number (last_char-first_char+1)
#define array_size (chars_number*chars_number)

struct array_pos {
    int ll;
    int uu;
    int lu;
    int ul;
};

struct pstat {
    unsigned long p;
    unsigned long s;
    unsigned long e;
};

iconv_t icnv=(iconv_t)-1;

int end_symbol(char ch) {
    if (ch=='\r'||ch=='\n'||ch==0||ch==' '||ch=='\t'||ch==','||ch=='.'||ch=='!'||ch=='?'||ch==';'||ch=='-'||ch==':'||ch=='"'||ch=='\''||ch==')') return 1;
    return 0;
}

int start_symbol(char ch) {
    if ((ch=='\t')||ch=='\r'||ch=='\n'||(ch==' ')||(ch=='(')||(ch=='"')||(ch=='\'')) return 1;
    return 0;
}    


unsigned char convert_char(unsigned char c) {
    char r;
    char *pr, *pc;
    size_t lr=1,lc=1;
    pr=&r;pc=&c;
    
    if (icnv == (iconv_t)-1) return c;
    if (iconv(icnv,&pc,&lc,&pr,&lr)<0) {
	printf("Error converting characters!\n");
	exit(1);
    }
    return r;
}

int get_array_pos(struct array_pos *pos, int a, int b) {
    int la,ua,lb,ub;
    if ((a<original_first_char)||(a>original_last_char)) return -1;
    if ((b<original_first_char)||(b>original_last_char)) return -1;
    
    la=tolower(a);
    ua=toupper(a);
    lb=tolower(b);
    ub=toupper(b);

    if ((la<original_first_char)||(la>original_last_char)) la=a;
    if ((lb<original_first_char)||(lb>original_last_char)) lb=b;
    if ((ua<original_first_char)||(ua>original_last_char)) ua=a;
    if ((ub<original_first_char)||(ub>original_last_char)) ub=b;
    
    la=convert_char(la);
    ua=convert_char(ua);
    lb=convert_char(lb);
    ub=convert_char(ub);
    
//    la=a;lb=b;ua=a;ub=b;
    
    pos->ll=(la-first_char)*chars_number+(lb-first_char);
    if (la!=ua) {
	pos->ul=(ua-first_char)*chars_number+(lb-first_char);
    } else {
	pos->ul=-1;
    } 
    if (lb!=ub) {
	pos->lu=(la-first_char)*chars_number+(ub-first_char);
    }
    else {
	pos->lu=-1;
    }
    if ((lb!=ub)&&(la!=ua)) {
	pos->uu=(ua-first_char)*chars_number+(ub-first_char);
    } else {
	pos->uu=-1;
    }
    return 0;
}


struct pstat *analyze(const unsigned char *text, unsigned long length) {
    struct pstat *a;
    unsigned long i;
    struct array_pos pos;
    
    a=(struct pstat*)malloc(array_size*sizeof(struct pstat));
    if (!a) return NULL;

    for (i=0;i<array_size;i++) {
	a[i].p=0;
	a[i].s=0;
	a[i].e=0;
    }
	
    for (i=1;i<length;i++) {
	if (get_array_pos(&pos,text[i-1],text[i])>=0) {
	    if (pos.ll>=0) {
		if ((i==1)||(start_symbol(text[i-2]))) a[pos.ll].s++;
		else if ((i+2==length)||(end_symbol(text[i+1]))) a[pos.ll].e++;
		else a[pos.ll].p++;
	    }
	    if (pos.ul>=0) {
		if ((i==1)||(start_symbol(text[i-2]))) a[pos.ul].s++;
		else if ((i+2==length)||(end_symbol(text[i+1]))) a[pos.ul].e++;
		else a[pos.ul].p++;
	    }
//	    if (pos.lu>=0) {
//		if ((i==1)||(start_symbol(text[i-2]))) a[pos.lu].s++;
//		else if ((i+2==length)||(end_symbol(text[i+1]))) a[pos.lu].e++;
//		else a[pos.lu].p++;
//	    }
	    if (pos.uu>=0) {
		if ((i==1)||(start_symbol(text[i-2]))) a[pos.uu].s++;
		else if ((i+2==length)||(end_symbol(text[i+1]))) a[pos.uu].e++;
		else a[pos.uu].p++;
	    }
	}
    }
    return a;
}


int print(struct pstat *a) {
    int i,j,k,n;
    
    for (i=first_char,k=0,n=0;i<=last_char;i++)
	for (j=first_char;j<=last_char;j++,k++) {
	    if ((a[k].p)||(a[k].s)||(a[k].e)) {
		if ((n)&&(n%8==0)) printf(",\n");
		else if (n) printf(", ");
		printf("{'%c','%c',%lf,%lf,%lf}",i,j,a[k].p?log10(a[k].p):-2,a[k].s?log10(a[k].s):-2,a[k].e?log10(a[k].e):-2);
		n++;
	    }
	}
    if ((n%8)!=1) printf("\n");
    return n;
}


unsigned long npow(unsigned long n) {
    unsigned long res=2;
    while (res<=n) res*=2;
    return res;
}

main(int argc, char *argv[]) {
    FILE *f;
    struct stat st;
    unsigned char *text;
    unsigned long len;
    struct pstat *a;
    int num;
    long i,sum;
    char locale[32];


    if (argc!=3) {
	printf("Usage: %s <file name> <encoding>\n",argv[0]);
	exit(0);
    }

    if (strlen(argv[2])>12) {
	printf("Invalid encoding(%s) specified!\n",argv[2]);
	exit(1);
    }
    
    if ((!strcasecmp(argv[2],"koi"))||(!strcasecmp(argv[2],"koi8"))||(!strcasecmp(argv[2],"koi-8"))||(!strcasecmp(argv[2],"koi8-r")))
    	sprintf(locale,"%s","KOI8-R");
    else if ((!strcasecmp(argv[2],"win"))||(!strcasecmp(argv[2],"cp1251"))||(!strcasecmp(argv[2],"cp-1251"))||(!strcasecmp(argv[2],"win1251"))||(!strcasecmp(argv[2],"win-1251")))
	sprintf(locale,"%s","CP1251");
    else if ((!strcasecmp(argv[2],"alt"))||(!strcasecmp(argv[2],"cp866"))||(!strcasecmp(argv[2],"cp-866"))||(!strcasecmp(argv[2],"ibm866"))||(!strcasecmp(argv[2],"ibm-866")))
	sprintf(locale,"%s","IBM866");
    else
	sprintf(locale,"%s",argv[2]);
    
    if (!setlocale(LC_CTYPE,"")) {
	printf("Can't set locale!\n");
	exit(1);
    }

    if (strcmp(locale,nl_langinfo(CODESET))) {
	if ((icnv=iconv_open(locale,nl_langinfo(CODESET)))<0) {
	    printf("Can't initialize iconv!\n");
	    exit(1);
	}
    }
    
    
    if (stat(argv[1],&st)) {
	printf("Specified file can't be stated!\n");
	iconv_close(icnv);
	exit(1);
    }
    
    if (!S_ISREG(st.st_mode)) {
	printf("Specified file isn't regular file!\n");
	iconv_close(icnv);
	exit(1);
    }
    
    text=(unsigned char*)malloc(st.st_size);
    if (!text) {
	printf("Can't allocate %lu bytes of memory!\n",st.st_size);
	iconv_close(icnv);
	exit(1);
    }
    
    f=fopen(argv[1],"r");
    if (!f) {
	printf("Failed to open specified file. Check permissions!\n");
	free(text);
	iconv_close(icnv);
	exit(1);
    }
    if (fread(text,1,st.st_size,f)!=st.st_size) {
	printf("Problem reading specified file!\n");
	free(text);
	fclose(f);
	iconv_close(icnv);
	exit(1);
    }
    fclose(f);
    
    a=analyze(text,st.st_size);
    if (a) {
	printf("static const lng_stat2 enc_%s[]={\n",argv[2]);
	num=print(a);
	printf("};\n\n");
	free(a);
	fprintf(stderr,"static unsigned int indexes2=%lu;\n",num);
	fprintf(stderr,"static unsigned int npow2=%lu;\n",npow(num));
    } else printf("Failed to allocate %lu bytes of memory!\n",array_size*sizeof(struct pstat));

    free(text);
    iconv_close(icnv);
}