/*
  Copyright (C) 1991-2002, The Numerical Algorithms Group Ltd.
  All rights reserved.
  Copyright (C) 2007-2009, Gabriel Dos Reis.
  All rights reserved.

  Redistribution and use in source and binary forms, with or without
  modification, are permitted provided that the following conditions are
  met:

      - Redistributions of source code must retain the above copyright
        notice, this list of conditions and the following disclaimer.

      - Redistributions in binary form must reproduce the above copyright
        notice, this list of conditions and the following disclaimer in
        the documentation and/or other materials provided with the
        distribution.

      - Neither the name of The Numerical Algorithms Group Ltd. nor the
        names of its contributors may be used to endorse or promote products
        derived from this software without specific prior written permission.

  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
  IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
  TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
  PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
  OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
  LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/

/*
 * hthits pattern htdb-file
 *
 * Scan HyperDoc files for a given pattern.
 *
 * The output contains lines of the form:
 *
 * page-name`title`n
 *
 * The title and body of each page are scanned but the name is not. It is
 * possible that the title matches but not any lines. The number of matches
 * in the page (n) is given last.
 *
 * SMW Feb 91
 */

#include "openaxiom-c-macros.h"

#include "debug.h"

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <ctype.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <regex.h>
#include <locale.h>

#include "cfuns.h"

/*
 * For fixed-size arrays.
 */
#define MAX_HTDB_LINE   1024
#define MAX_ENTRY_TYPE  30      /* I.e. \page \newcommand \patch ... */
#define MAX_ENTRY_NAME  1024    /* E.g. DifferentialCalculusPage */
#define MAX_COMP_REGEX  1024

typedef struct PgInfo {
    char name[MAX_ENTRY_NAME];
    long start, size;
} PgInfo ;

/*
 * Global variables set according to the command line.
 */

char *progName;
char *pattern;
char *htdbFName;
int gverifydates=0;
regex_t reg_pattern;

static void 
badDB(void)
{
   fprintf(stderr, "%s:  bad database file %s\n", progName, htdbFName);
   exit(1);
}


static void 
untexbuf(register char* s)
{
   register char *d = s;
   
   while (*s)
      switch (*s) {
      case '\\':
         *d++ = ' ';
         s++;
         if (*s != '%')
            while (isalpha(*s))
               s++;
         break;
      case '%':
         *d++ = ' ';
         s++;
         while (*s && *s != '\n')
            s++;
         break;
      case '{':
      case '}':
      case '#':
         *d++ = ' ';
         s++;
         break;
      default:
         *d++ = *s++;
      }
   *d = 0;
}


/*
 * Any newlines and separator characters in the title are changed to blanks.
 */

static void 
splitpage(char* buf, char** ptitle, char** pbody)
{
   int n, depth, tno;
   char *s;
   
   switch (buf[1]) {
   case 'p':
      tno = 2;
      break;                  /* \page{Name}{Title} */
   case 'b':
      tno = 3;
      break;                  /* \begin{page}{Name}{Title} */
   default:
      fprintf(stderr, "%s: Invalid page format: %s\n", progName, buf);
      exit(1);
   }

   n = 0;
   depth = 0;
   
   for (s = buf; *s; s++) {
      if (*s == '{')
         if (++depth == 1 && ++n == tno)
            *ptitle = s + 1;
      if (*s == '}')
         if (depth-- == 1 && n == tno) {
            *s = 0;
            *pbody = s + 1;
            break;
         }
   }
}


/*
 * Given string s and length n, output ` followed by the first n characters
 * of s with ` and newline converted to blanks. This function destructively
 * modifies s.
 */

static void 
squirt(char* s, int n)
{
   register char *t, *e;
   int c;
   
   c = s[n];
   
   for (t = s, e = s + n; t < e; t++)
      if (*t == '`' || *t == '\n')
         *t = ' ';
   
   if (s[n] != 0) {
      s[n] = 0;
   }
   printf("{%.*s}", n, s);
   s[n] = c;
}

static void 
searchPage(char* pgname, char* pgtitle, char* pgbody)
{
   char *bodyrest;
   regmatch_t match_pos;
   int nhits = 0;
   
   if (!regexec(&reg_pattern, pgtitle, 1, &match_pos, 0)) 
      nhits++;
   
   bodyrest = pgbody;
   while (!regexec(&reg_pattern, bodyrest, 1, &match_pos, 0)) {
      nhits++;
      bodyrest += match_pos.rm_eo;
   }
   if (nhits) {
      printf("\\newsearchresultentry{%d}{%s}",nhits, pgtitle);
      squirt(pgname, strlen(pgname));
      printf("\n");
   }
}

static void
handlePage(FILE* infile, PgInfo* pg)
{
   static char *pgBuf = 0;
   static int pgBufSize = 0;
   
   char *title, *body;
   
   if (pg->size > pgBufSize - 1) {
      if (pgBuf)
         free(pgBuf);
      pgBufSize = pg->size + 20000;
      pgBuf = (char *)malloc(pgBufSize);
      
      if (!pgBuf) {
         fprintf(stderr,"%s: Out of memory\n", progName);
         exit(1);
      }
   }
   
   fseek(infile, pg->start, 0);
   fread(pgBuf, pg->size, 1, infile);
   pgBuf[pg->size] = 0;
   
   splitpage(pgBuf, &title, &body);
   /*untexbuf(title);*/
   untexbuf(body);

#ifdef DEBUG
   printf("-------------- %s -------------\n%s", pg->name, pgBuf);
   printf("============== %s =============\n", title);
   printf("%s", body);
#endif
   
   searchPage(pg->name, title, body);
}

static void
handleFilePages(const char* fname, int pgc, PgInfo* pgv)
{
   FILE *infile;
   int i;
   
   infile = fopen(fname, "r");
   if (infile == NULL) {
      fprintf(stderr, "%s: Cannot read file %s\n", progName, fname);
      exit(1);
   }

   for (i = 0; i < pgc; i++)
      handlePage(infile, pgv + i);
   
   fclose(infile);
}

static void
handleFile(FILE* htdbFile)
{
   static PgInfo *pgInfoV = 0;
   static int pgInfoC = 0;
   
   char htdbLine[MAX_HTDB_LINE];
   char htfname[MAX_HTDB_LINE];
   time_t httime;
   long htsize;
   struct stat htstat;
   
   long fstart, fend;
   int rc, i, npages;
   
   char entname[MAX_ENTRY_NAME], enttype[MAX_ENTRY_TYPE];
   long entoffset, entlineno;
   
   fgets(htdbLine, MAX_HTDB_LINE, htdbFile);
   
   sscanf(htdbLine, " %s %ld", htfname, &httime);
   
   /*
    * 1. Verify file: get size and check modification time.
    */
   rc = stat(htfname, &htstat);
   if (rc == -1) {
      fprintf(stderr, "%s: Cannot access %s\n", progName, htfname);
      exit(1);
   }
   if (gverifydates && (htstat.st_mtime != httime)) {
      
      fprintf(stderr, "%s: Out of date file %s\n", progName, htfname);
      exit(1);
   }
   htsize = htstat.st_size;
   
   /*
    * 2. Count the pages in the file.
    */
   npages = 0;
   fstart = ftell(htdbFile);
   fend = ftell(htdbFile);
   
   while (fgets(htdbLine, MAX_HTDB_LINE, htdbFile) != NULL) {
      if (htdbLine[0] == '\t')
         break;
      if (!strncmp(htdbLine, "\\page", 5))
         npages++;
      fend = ftell(htdbFile);
   }
   
   /*
    * 3. Find offset and size of each \page (skipping \newcommands etc.)
    */
   if (npages > pgInfoC) {
      if (pgInfoV)
         free(pgInfoV);
      
      pgInfoC = npages;
      pgInfoV = (PgInfo *)
         malloc(npages * sizeof(PgInfo));
      
      if (!pgInfoV) {
         fprintf(stderr, "%s: out of memory\n", progName);
         exit(1);
      }
   }
   
   fseek(htdbFile, fstart, 0);
   
   for (i = 0; fgets(htdbLine, MAX_HTDB_LINE, htdbFile) != NULL;) {
      if (htdbLine[0] == '\t')
         break;
      
      sscanf(htdbLine, "%s %s %ld %ld",
             enttype, entname, &entoffset, &entlineno);
      
      if (i > 0 && pgInfoV[i - 1].size == -1)
         pgInfoV[i - 1].size = entoffset - pgInfoV[i - 1].start;
      
      if (!strcmp(enttype, "\\page")) {
         strncpy(pgInfoV[i].name, entname, MAX_ENTRY_NAME);
         pgInfoV[i].start = entoffset;
         pgInfoV[i].size = -1;
         
         i++;
      }
   }
   if (i > 0 && pgInfoV[i - 1].size == -1)
      pgInfoV[i - 1].size = htsize - pgInfoV[i - 1].start;
   
   if (i != npages)
      badDB();
   
   /*
    * 4. Position database input to read next file-description
    */
   fseek(htdbFile, fend, 0);
   
   /*
    * 5. Process the pages of the file.
    */
   handleFilePages(htfname, npages, pgInfoV);
}

static void
handleHtdb(void)
{
   FILE *htdbFile;
   int c;
   
   htdbFile = fopen(htdbFName, "r");
   if (htdbFile == NULL)
      badDB();
   
   while ((c = getc(htdbFile)) != EOF) {
      if (c != '\t')
         badDB();
      ungetc(c, htdbFile);
      
      handleFile(htdbFile);
   }
   fclose(htdbFile);
}

static void
cmdline(int argc, char** argv)
{
   progName = argv[0];
   
   if (argc != 3) {
      fprintf(stderr, "Usage: %s pattern htdb-file\n", progName);
      exit(1);
   }
   
   pattern = argv[1];
   htdbFName = argv[2];
}


int
main(int argc, char** argv)
{
    putenv("LC_ALL=C");
    setlocale(LC_ALL, "");
    cmdline(argc, argv);
    regcomp(&reg_pattern, pattern, REG_NEWLINE);
    handleHtdb();
    return(0);
}
