#include "license.readme"

#include <cstdlib>
#include <cctype>
#include <cstring>
#include <cstdio>

#include "suggestmgr.hxx"

extern char * mystrdup(const char *);


SuggestMgr::SuggestMgr(const char * tryme, int maxn, 
                       AffixMgr * aptr)
{

  // register affix manager and check in string of chars to 
  // try when building candidate suggestions
  pAMgr = aptr;
  ctry = mystrdup(tryme);
  ctryl = 0;
  if (ctry)
    ctryl = strlen(ctry);
  maxSug = maxn;
}


SuggestMgr::~SuggestMgr()
{
  pAMgr = NULL;
  if (ctry) free(ctry);
  ctry = NULL;
  ctryl = 0;
  maxSug = 0;
}



// generate suggestions for a mispelled word
//    pass in address of array of char * pointers

int SuggestMgr::suggest(char*** slst, const char * word)
{
    
    int nsug = 0;
    char ** wlst = (char **) calloc(maxSug, sizeof(char *));
    if (wlst == NULL) return -1;

    // perhaps we made a typical fault of spelling
    nsug = replchars(wlst, word, nsug);

    // did we forget to add a char
    if ((nsug < maxSug) && (nsug > -1))
    nsug = forgotchar(wlst, word, nsug);

    // did we swap the order of chars by mistake
    if ((nsug < maxSug) && (nsug > -1))
      nsug = swapchar(wlst, word, nsug);

    // did we add a char that should not be there
    if ((nsug < maxSug) && (nsug > -1))
      nsug = extrachar(wlst, word, nsug);
   
    // did we just hit the wrong key in place of a good char
    if ((nsug < maxSug) && (nsug > -1))
      nsug = badchar(wlst, word, nsug);

    // perhaps we forgot to hit space and two words ran together
    if ((nsug < maxSug) && (nsug > -1))
      nsug = twowords(wlst, word, nsug);

    if (nsug < 0) {
       for (int i=0;i<maxSug; i++)
	 if (wlst[i] != NULL) free(wlst[i]);
       free(wlst);
       return -1;
    }

    *slst = wlst;
    return nsug;
}



// suggestions for a typical fault of spelling, that
// differs with more, than 1 letter from the right form.
int SuggestMgr::replchars(char** wlst, const char * word, int ns)
{
  char candidate[MAXSWL];
  const char * r;
  int lenr, lenp;
  int cwrd;

  int wl = strlen(word);
  if (wl < 2 || ! pAMgr) return 0;

  int numrep = pAMgr->get_numrep();
  struct replentry* reptable = pAMgr->get_reptable();
  if (reptable==NULL) return 0;

  for (int i=0; i < numrep; i++ ) {
      r = word;
      lenr = strlen(reptable[i].replacement);
      lenp = strlen(reptable[i].pattern);
      // search every occurence of the pattern in the word
      while ((r=strstr(r, reptable[i].pattern)) != NULL) {
	  strcpy(candidate, word);
	  if (r-word + lenr + strlen(r+lenp) >= MAXSWL) break;
	  strcpy(candidate+(r-word),reptable[i].replacement);
	  strcpy(candidate+(r-word)+lenr, r+lenp);
          cwrd = 1;
          for (int k=0; k < ns; k++)
	      if (strcmp(candidate,wlst[k]) == 0) cwrd = 0;
          if ((cwrd) && check(candidate,strlen(candidate))) {
	      if (ns < maxSug) {
		  wlst[ns] = mystrdup(candidate);
		  if (wlst[ns] == NULL) {
		      for (int j=0; j<ns; j++) free(wlst[j]);
		      return -1;
		  }
		  ns++;
	      } else return ns;
	  }
          r++; // search for the next letter
      }
   }
   return ns;
}


// error is wrong char in place of correct one
int SuggestMgr::badchar(char ** wlst, const char * word, int ns)
{
  char	tmpc;
  char	candidate[MAXSWL];

  int wl = strlen(word);
  int cwrd;
  strcpy (candidate, word);

  // swap out each char one by one and try all the tryme
  // chars in its place to see if that makes a good word
  for (int i=0; i < wl; i++) {
    tmpc = candidate[i];
    for (int j=0; j < ctryl; j++) {
       if (ctry[j] == tmpc) continue;
       candidate[i] = ctry[j];
       cwrd = 1;
       for (int k=0; k < ns; k++)
	 if (strcmp(candidate,wlst[k]) == 0) cwrd = 0;
       if ((cwrd) && check(candidate,wl)) {
	 if (ns < maxSug) {
            wlst[ns] = mystrdup(candidate);
            if (wlst[ns] == NULL) return -1;
            ns++;
         } else return ns;
       }
       candidate[i] = tmpc;
    }
  }
  return ns;
}


// error is word has an extra letter it does not need 
int SuggestMgr::extrachar(char** wlst, const char * word, int ns)
{
   char	   candidate[MAXSWL];
   const char *  p;
   char *  r;
   int cwrd;

   int wl = strlen(word);
   if (wl < 2) return 0;

   // try omitting one char of word at a time
   strcpy (candidate, word + 1);
   for (p = word, r = candidate;  *p != 0;  ) {
       cwrd = 1;
       for (int k=0; k < ns; k++)
	 if (strcmp(candidate,wlst[k]) == 0) cwrd = 0;
       if ((cwrd) && check(candidate,wl-1)) {
	 if (ns < maxSug) {
            wlst[ns] = mystrdup(candidate);
            if (wlst[ns] == NULL) return -1;
            ns++;
         } else return ns; 
       }
       *r++ = *p++;
   }
   return ns;
}


// error is mising a letter it needs
int SuggestMgr::forgotchar(char ** wlst, const char * word, int ns)
{
   char	candidate[MAXSWL];
   const char *	p;
   char *	q;
   int cwrd;

   int wl = strlen(word);

   // try inserting a tryme character before every letter
   strcpy(candidate + 1, word);
   for (p = word, q = candidate;  *p != 0;  )  {
      for (int i = 0;  i < ctryl;  i++) {
	 *q = ctry[i];
         cwrd = 1;
         for (int k=0; k < ns; k++)
	   if (strcmp(candidate,wlst[k]) == 0) cwrd = 0;
         if ((cwrd) && check(candidate,wl+1)) {
	    if (ns < maxSug) {
                wlst[ns] = mystrdup(candidate);
                if (wlst[ns] == NULL) return -1;
                ns++;
            } else return ns; 
         }
      }
      *q++ = *p++;
   }

   // now try adding one to end */
   for (int i = 0;  i < ctryl;  i++) {
      *q = ctry[i];
      cwrd = 1;
      for (int k=0; k < ns; k++)
	if (strcmp(candidate,wlst[k]) == 0) cwrd = 0;
      if ((cwrd) && check(candidate,wl+1)) {
	 if (ns < maxSug) {
             wlst[ns] = mystrdup(candidate);
             if (wlst[ns] == NULL) return -1;
             ns++;
         } else return ns;
      }
   }
   return ns;
}


/* error is should have been two words */
int SuggestMgr::twowords(char ** wlst, const char * word, int ns)
{
    char candidate[MAXSWL];
    char * p;

    int wl=strlen(word);
    if (wl < 3) return ns;
    strcpy(candidate + 1, word);

    // split the string into two pieces after every char
    // if both pieces are good words make them a suggestion
    for (p = candidate + 1;  p[1] != '\0';  p++) {
       p[-1] = *p;
       *p = '\0';
       if (check(candidate,strlen(candidate))) {
	 if (check((p+1),strlen(p+1))) {
	    *p = ' ';
	    if (ns < maxSug) {
                wlst[ns] = mystrdup(candidate);
                if (wlst[ns] == NULL) return -1;
                ns++;
            } else return ns;
         }
       }
    }
    return ns;
}


// error is adjacent letter were swapped
int SuggestMgr::swapchar(char ** wlst, const char * word, int ns)
{
   char	candidate[MAXSWL];
   char * p;
   char	tmpc;
   int cwrd;

   int wl = strlen(word);

   // try swapping adjacent chars one by one
   strcpy(candidate, word);
   for (p = candidate;  p[1] != 0;  p++) {
      tmpc = *p;
      *p = p[1];
      p[1] = tmpc;
      cwrd = 1;
      for (int k=0; k < ns; k++)
	if (strcmp(candidate,wlst[k]) == 0) cwrd = 0;
      if ((cwrd) && check(candidate,wl)) {
	 if (ns < maxSug) {
             wlst[ns] = mystrdup(candidate);
             if (wlst[ns] == NULL) return -1;
             ns++;
         } else return ns;
      }
      tmpc = *p;
      *p = p[1];
      p[1] = tmpc;
   }
   return ns;
}


// see if a candidate suggestion is spelled correctly
// needs to check both root words and words with affixes
int SuggestMgr::check(const char * word, int len)
{
  struct hentry * rv=NULL;
  if (pAMgr) { 
    rv = pAMgr->lookup(word);
    if (rv == NULL) rv = pAMgr->affix_check(word,len);
  }
  if (rv) return 1;
  return 0;
}