#include<stdio.h>
#ifndef sun
#include<sys/ioctl.h>
#endif
#include<sys/termios.h>
#define lockfile "/mclab/imc/main/etc/oneword.lock"
#define wordfile "/mclab/imc/main/etc/oneword.words"
#define lastuser "/mclab/imc/main/etc/oneword.lastuser"
#define worduser "/mclab/imc/main/etc/oneword.worduser"
#include<sys/types.h>
#include<sys/stat.h>
#include<string.h>

FILE *f;
int check();
void print();
void die();
int uid;
int width=70;

main()
{
   struct stat sbuf;
   unsigned size;
   char word[100];
   int p;
   int y;
   int w;
   int e;
   int para;
   struct winsize sz;
   char c;
   
   uid=getuid();
   
   if(!ioctl(0,TIOCGWINSZ,&sz))width=sz.ws_col-1;
   if(width<40||width>100)width=70;
   
   while(1){
      if (stat(wordfile,&sbuf)==-1)die(1);
      size=sbuf.st_size;
      puts("The story so far..."),
      print(),
      putchar('\n');
      if(check())puts("Sorry, you were the last person to add a word."),
                 puts("Please try again later."),
                 exit(1);
      puts("Enter your word. If you want to start a new paragraph,"),
      puts("prefix your word with a space."),
      puts("If you do not want to enter a word, just press return."),
      gets(word),
      word[99]=0;
      if(strlen(word)>width/2){
         puts("Sorry, your word is too long. It may not be added.");
         continue;
      }
      
      for(p=0;word[p]==' ';p++); /* p=first non-blank char */
      if(!word[p])exit(0);
      for(e=p;(c=word[e])&&strchr(")\"\'!,.:;?}] ",c);e++);
      while(e>p&&word[e-1]==' ')e--;  /* e=first non-punctuation */
      for(w=e;(c=word[w])&&c==' ';w++); /* w=first non-blank char after punct */
      
      for(y=w;c=word[y];y++)
         if(c<=' '||c>0x7e)w=-1;
      if(w==-1){
         puts("Sorry, your word contains an invalid character. It may not be added.");
         continue;
      }
      if(e>p&&word[e-1]=='\"'&&(e-1>p&&word[e-2]==' '||e-1==p&&word[e]!=' '))
         for(e--;e>p&&word[e-1]==' ';e--); /* discount opening quotes */
      
      if(!(f=fopen(lockfile,"a")))die(2);
      fwrite("*",1,1,f),
      y=(int)ftell(f),
      fclose(f);
      if(y>1){
         puts("Sorry, someone is just updating the file."),
         puts("Please wait then try again."),
         sleep(2);
         continue;
      }
      if (stat(wordfile,&sbuf)==-1)die(1);
      if (size!=sbuf.st_size) puts("Sorry, someone has updated the file."),
                             puts("Please try again."),
                             unlink(lockfile);
      else {
         if(!(f=fopen(wordfile,"a"))) unlink(lockfile),die(3);
         para=p;
         while(e>p)if((c=word[p++])!=' ')fputc(c,f);
         if(para)fputc('\n',f);
         else if(word[w])fputc(' ',f);
         while(p<w)if((c=word[p++])!=' ')fputc(c,f);
         fputs(word+p,f),
         fclose(f);
         if(word[w]){
            if(!(f=fopen(lastuser,"w"))) unlink(lockfile),die(5);
            fprintf(f,"%d\n",uid);
            fclose(f);
         }
         unlink(lockfile);
         if(word[w]){
            if(!(f=fopen(worduser,"a"))) die(4);
            fprintf(f,"%d ",uid);
            fclose(f);
         }
         puts("Thankyou for your contribution.");
         exit(0);
      }
   }
}

int check()
{
   int last;
   if(!(f=fopen(lastuser,"r")))die(5);
   fscanf(f,"%d",&last);
   fclose(f);
   return last==uid;
}

void print()
{
   char words[200];
   int p=0;
   int s=0;
   int i;
   char c;
   
   if(!(f=fopen(wordfile,"r")))die(3);
   while(1){
      c=fgetc(f);
      if(feof(f)||ferror(f))break;
      if(c=='\n'){
         words[p]=0;
         puts(words);
         putchar('\n');
         p=0;
         continue;
      }
      if (c==' ')s=p;
      words[p++]=c;
      if(p>width){
         words[s]=0;
         puts(words);
         for(i=0;i<p-s-1;i++)words[i]=words[i+s+1];
         p-=s+1;
      }
   }
   fclose(f);
   if(p) words[p]=0,puts(words);
}

void die(rc)
int rc;
{
   puts("Something seems to have gone wrong with the");
   switch(rc){
      case 1:
      case 3: printf("word");
         break;
      case 2: printf("lock");
         break;
      case 5:
      case 4: printf("users");
   }
   puts(" file. Sorry!");
   exit(rc);
}