/* This software is Copyright 1989, 1990, 1992, 1993 by various individuals.
   Please see the accompanying file COPYRIGHT for details. */

#include <stdio.h>
#include <errno.h>
#include <unistd.h>
#include <sys/stat.h>
#include <sys/file.h>

#include "db.h"
#include "help.h"
#include "defs.h"
#include "config.h"
#include "params.h"
#include "externs.h"
#include "strings.h"
#include "interface.h"

static void update_index(const char *indxfile, const char *textfile)
{
 long int pos;
 int n;
 int lineno;
 int lineinc;
 int ntopics;
 help_indx entry;
 FILE *rfp;
 FILE *wfp;
 char line[LINE_SIZE+1];
 char *topic;

 fprintf(stderr,"Updating index file:%s\n",indxfile);
 rfp = fopen(textfile,"r");
 if (! rfp)
  { fprintf(stderr,"can't open %s for reading\n",textfile);
    return;
  }
 wfp = fopen(indxfile,"w");
 if (! wfp)
  { fprintf(stderr,"can't open %s for writing\n",indxfile);
    fclose(rfp);
    return;
  }
 pos = 0;
 lineno = 0;
 ntopics = 0;
 lineinc = 1;
 while (fgets(&line[0],sizeof(line),rfp) == &line[0])
  { lineno += lineinc;
    lineinc = 1;
    n = strlen(line);
    if ((n > 0) && (line[n-1] != '\n'))
     { fprintf(stderr,"line %d: line too long\n",lineno);
       lineinc = 0;
     }
    if (index(&line[0],'\t'))
     { fprintf(stderr,"%s contains a tab (line %d)\n",textfile,lineno);
     }
#if 0 /* mustn't modify n at this point */
    if (index(&line[0],'\t'))
     { int inc;
       int outgrew;
       fprintf(stderr,"%s contains a tab (line %d), patching\n",textfile,lineno);
       outgrew = 0;
       for (i=0;line[i];i++)
	{ if (line[i] == '\t')
	   { line[i] = ' ';
	     inc = ((i + 8) & ~7) - i - 1;
	     if (inc > 0)
	      { n += inc;
		if (n >= sizeof(line))
		 { outgrew += n - (sizeof(line)-1);
		   n = sizeof(line) - 1;
		 }
		bcopy(line+i+1,line+i+1+inc,n-(i+1+inc)+1);
		for (;inc>0;inc--) line[i+inc] = ' ';
	      }
	   }
	}
       if (outgrew)
	{ fprintf(stderr,"%s line %d too long after fixup, lost last %d char%s\n",textfile,lineno,outgrew,(outgrew==1)?"":"s");
	}
     }
#endif
    if (! strncmp(line,HELP_TOPIC_MARK,sizeof(HELP_TOPIC_MARK)-1))
     { ntopics ++;
       if (ntopics > 1)
	{ entry.loc.len = pos - entry.loc.pos;
	  if (fwrite(&entry,sizeof(entry),1,wfp) != 1)
	   { fprintf(stderr,"error writing %s\n",indxfile);
	     fclose(wfp);
	     fclose(rfp);
	     unlink(indxfile);
	     return;
	   }
	}
       line[n-1] = '\0';
       topic = &line[3];
       while (*topic && (*topic == ' ')) topic ++;
       strncpy(&entry.topic[0],topic,TOPIC_NAME_LEN);
       entry.topic[TOPIC_NAME_LEN] = '\0';
       entry.loc.pos = pos + n;
     }
    else
     { if (lineno == 1)
	{ fprintf(stderr,"%s doesn't begin with a topic marker\n",textfile);
	  fclose(wfp);
	  fclose(rfp);
	  unlink(indxfile);
	  return;
	}
     }
    pos += n;
  }
 entry.loc.len = pos - entry.loc.pos;
 if (fwrite(&entry,sizeof(entry),1,wfp) != 1)
  { fprintf(stderr,"error writing %s\n",indxfile);
    fclose(rfp);
    fclose(wfp);
    unlink(indxfile);
    return;
  }
 fclose(rfp);
 fclose(wfp);
}

void spit_file(dbref player, const char *filename)
{
  FILE *f;
  char buf[BUFFER_LEN];
  char *p;

  if((f = fopen(filename, "r")) == NULL)
  {
    sprintf(buf, "Sorry, %s is broken.  Management has been notified.",
      filename);
    notify(player, buf);
    fputs("spit_file:", stderr);
    perror(filename);
  }
  else
  {
    while(fgets(buf, sizeof buf, f))
    {
      for(p = buf; *p; p++) if(*p == '\n')
      {
        *p = '\0';
        break;
      }
      notify(player, buf);
    }
    fclose(f);
  }
}

void do_help(dbref player, const char *arg1, const char *deftopic,
  const char *indxfile, const char *textfile)
{
 int textfd;
 int indxfd;
 int i;
 int listmatches;
 int prefcount;
 int looped;
 FILE *fp;
 help_filepart best;
 help_indx indxent;
 struct stat textstat;
 struct stat indxstat;
 char buf[BUFFER_LEN];

 looped = 0;
top:;
 textfd = open(textfile,O_RDONLY,0);
 if (textfd < 0)
  { i = errno;
    sprintf(&buf[0],"Sorry, %s is (temporarily, we hope) broken.",deftopic);
    notify(player,&buf[0]);
    log_status("Can't open %s for reading: %s\n",textfile,strerror(i));
    return;
  }
 fstat(textfd,&textstat);
 indxfd = open(indxfile,O_RDONLY,0);
 if (indxfd < 0)
  { if (errno != ENOENT)
     { i = errno;
       sprintf(&buf[0],"Sorry, %s is (temporarily, we hope) broken.",deftopic);
       notify(player,&buf[0]);
       log_status("Can't open %s for reading: %s\n",indxfile,strerror(i));
       close(textfd);
       return;
     }
    indxstat.st_mtime = 0;
  }
 else
  { fstat(indxfd,&indxstat);
  }
 if (indxstat.st_mtime < textstat.st_mtime)
  { close(indxfd);
    update_index(indxfile,textfile);
    indxfd = open(indxfile,O_RDONLY,0);
    if (indxfd < 0)
     { i = errno;
       sprintf(&buf[0],"Sorry, %s is (temporarily, we hope) broken.",deftopic);
       notify(player,&buf[0]);
       log_status("Can't open %s for reading after update: %s\n",indxfile,strerror(i));
       close(textfd);
       return;
     }
  }
 fp = fdopen(indxfd,"r");
 if (fp == 0)
  { close(textfd);
    close(indxfd);
    sprintf(&buf[0],"Sorry, %s is rather ill.",deftopic);
    notify(player,&buf[0]);
    log_status("Can't fdopen %s\n",indxfile);
    return;
  }
 if (!arg1 || !*arg1) arg1 = deftopic;
 listmatches = 0;
 if ((arg1[0] == '?') && (arg1[1] == ' '))
  { listmatches = 1;
    while (*++arg1 == ' ') ;
    if (!*arg1)
     { sprintf(&buf[0],"Use plain `%s' for a list of topics.",deftopic);
       notify(player,&buf[0]);
       fclose(fp);
       close(textfd);
       return;
     }
  }
 prefcount = 0;
 while (fread(&indxent,sizeof(indxent),1,fp) == 1)
  { if (string_prefix(&indxent.topic[0],arg1))
     { prefcount ++;
       if (listmatches)
	{ if (prefcount == 1)
	   { sprintf(&buf[0],"Matches for %s in %s:",arg1,deftopic);
	     notify(player,&buf[0]);
	   }
	  notify(player,&indxent.topic[0]);
	}
       else
	{ best = indxent.loc;
	  if (!string_compare(&indxent.topic[0],arg1))
	   { prefcount = 1;
	     break;
	   }
	}
     }
  }
 if (listmatches)
  { if (prefcount == 0)
     { sprintf(&buf[0],"No match for %s found in %s.",arg1,deftopic);
     }
    else
     { sprintf(&buf[0],"%d match%s found.",prefcount,(prefcount==1)?"":"es");
     }
    notify(player,&buf[0]);
    fclose(fp);
    close(textfd);
    return;
  }
 fclose(fp);
 if (prefcount == 0)
  { sprintf(&buf[0],"No %s for `%s'.",deftopic,arg1);
    notify(player,&buf[0]);
    close(textfd);
    return;
  }
 if (prefcount > 1)
  { sprintf(&buf[0],"`%s %s' is ambiguous; %d matches found.",deftopic,arg1,prefcount);
    notify(player,&buf[0]);
    sprintf(&buf[0],"Use `%s ? %s' to list them.",deftopic,arg1);
    notify(player,&buf[0]);
    close(textfd);
    return;
  }
 fp = fdopen(textfd,"r");
 if (fp == 0)
  { close(textfd);
    sprintf(&buf[0],"Sorry, %s is rather ill.",deftopic);
    notify(player,&buf[0]);
    log_status("Can't fdopen %s\n",textfile);
    return;
  }
 if (fseek(fp,best.pos,0) < 0)
  { if (looped)
     { sprintf(&buf[0],"Sorry, %s is out of order.",deftopic);
       notify(player,&buf[0]);
       fclose(fp);
       return;
     }
    looped = 1;
    unlink(indxfile);
    fclose(fp);
    goto top;
  }
 while (fgets(&buf[0],sizeof(buf),fp))
  { if (!strncmp(&buf[0],HELP_TOPIC_MARK,strlen(HELP_TOPIC_MARK))) break;
    i = strlen(&buf[0]);
    if ((i > 0) && (buf[i-1] == '\n')) buf[--i] = '\0';
    if (i == 0)
     { buf[0] = ' ';
       buf[1] = '\0';
     }
    notify(player,&buf[0]);
  }
 fclose(fp);
}