#include <stdio.h>
#include <string.h>
#include <stdlib.h>

void stripSpaces ( char * str )
{
  char * dst, * str_src;
  int inSpaces = 1;
  dst = str, str_src = str;

  while ( * str_src )
  {
    if ( inSpaces )
    {
      // Copies everything expcept for spaces
      if ( * str_src != ' ' && * str_src != '\t' )
      {
        * dst ++ = * str_src;
        inSpaces = 0;
      }
    }
    else
    {
      /**
       * If not in spaces, this copies everything, including one space.
       * If theres more than one space, this switches to "inSpaces" mode.
      **/
     * dst ++ = * str_src;
     if ( * str_src == ' ' || * str_src == '\t' ) inSpaces = 1;
    }
    str_src ++;
  }

  // If str was an empty string, this prevents it from moving one character back.
  if ( inSpaces && dst > str ) dst --;

  * dst = 0;
}

void removeLF ( char * str )
{
  int len = strlen ( str ), i = 0, start = 0, end = 0;

  // Sets start to the first letter of string
  while ( len > start && ( str[start] == '\n' || str[start] == ' ' ) ) start ++;

  // Sets end to the last letter of string
  while ( len > end && str[len-end-1] == '\n' ) str[len-end++-1] = 0;
  end = len-end-1;

  // Aligns string to the left if not already aligned and trims newlines
  while ( start <= len )
  {
    if ( start <= end )
    {
      if ( str[start] != '\n' ) str[i] = str[start];
      else
      {
        while ( str[start+1] == '\n' )
          if ( str[start+2] == '\n' ) start ++;
          else
          {
            str[i] = '\n';
            i ++;
            start ++;
            break;
          }
        str[i] = ' ';
      }
    }
    else str[i] = 0;
    i ++, start ++;
  }

}

int isDel ( char c )
{
  // Detects if char is a delimiter (1) or not (0)
  switch ( c )
  {
    case '\0':
    case '\t':
    case ' ':
      return 1;
      break;
    default:
      return 0;
  }
}

void printLine ( const char * start, const char * end )
{
  const char * p = start;
  while ( p <= end ) putchar ( * p ++ );
  putchar ( '\n' );
}

int setLength ( char * str, int width )
{
  width ++;
  int chars = 1;

  char * start   = & str[0],
       * end     = & str[0],
       * current = & str[0];

  while ( * current != '\0' )
  {
    while ( chars <= width )
    {
      while ( ! isDel ( * current ) )
        ++ current, ++ chars;

      if ( chars <= width )
      {
        if ( * current == '\0' )
        {
          puts ( start );
          return 0;
        }
        end = current - 1;
        current ++, chars ++;
      }
    }

    if ( end == start )
      end = current - 1;

    printLine ( start, end );
    current = end + 1;

    while ( isDel ( * current ) )
    {
      if ( * current == '\0' ) return 0;
      else ++ current;
    }
    start = current;
    end = current;
    chars = 1;
  }

  return 0;
}

char * wordWrap ( int width, const char * src )
{
  if ( width < 0 ) return NULL;

  // Allocates mem for the copy of src string and copies it to src_tp
  char * src_tp;
  src_tp = ( char * ) calloc ( strlen ( src ) + 1, sizeof ( char ) );
  strcpy ( src_tp, src );

  // Strips spaces and directly modifies the src_tp string
  stripSpaces ( src_tp );

  // Trims newlines and directly modifies the src_tp string
  removeLF ( src_tp );

  // Sets line length to specified width, NULL on error
  setLength ( src_tp, width );

  return src_tp;
}

int main ( void )
{
  char * res;

  const char * s0 =
    "Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Integer metus\n"
    "pede, pretium vitae, rhoncus et, auctor sit amet, ligula. Integer volutpat\n"
    "orci et elit. Nunc tempus, urna at sollicitudin rutrum, arcu libero rhoncus\n"
    "lectus, vitae feugiat purus orci ultricies turpis. Pellentesque habitant\n"
    "morbi tristique senectus et netus et malesuada fames ac turpis egestas. Nam\n"
    "in pede. Etiam eu sem id urna ultricies congue. Vestibulum porttitor\n"
    "ultrices neque. Mauris semper, mauris ut feugiat ultricies, augue purus\n"
    "tincidunt  elit, eu interdum ante nisl ac ante. Pellentesque dui. Vestibulum\n"
    "pretium, augue non cursus pretium, nibh dolor laoreet leo, sed pharetra pede\n"
    "libero non diam.";

  res = wordWrap ( 40, s0 );

  //puts ( res );

  return 0;
}