** full functionality of FTS4.
*/
#include "config.h"
#include "search.h"
#include <assert.h>

#if INTERFACE

/* Maximum number of search terms */
#define SEARCH_MAX_TERM   8

/*
** A compiled search pattern
*/
struct Search {
  int nTerm;            /* Number of search terms */
  struct srchTerm {     /* For each search term */
    char *z;               /* Text */
    int n;                 /* length */
  } a[SEARCH_MAX_TERM];


  /* Snippet controls */



  char *zMarkBegin;     /* Start of a match */   

  char *zMarkEnd;       /* End of a match */
  char *zMarkGap;       /* A gap between two matches */

  unsigned fSrchFlg;    /* Flags */












};


#define SRCHFLG_HTML  0x0001   /* Escape snippet text for HTML */




#endif



/*
** Theses characters constitute a word boundary
*/
static const char isBoundary[] = {
  1, 1, 1, 1, 1, 1, 1, 1,     1, 1, 1, 1, 1, 1, 1, 1,
  1, 1, 1, 1, 1, 1, 1, 1,     1, 1, 1, 1, 1, 1, 1, 1,

  0, 0, 0, 0, 0, 0, 0, 0,     0, 0, 0, 0, 0, 0, 0, 0,
  0, 0, 0, 0, 0, 0, 0, 0,     0, 0, 0, 0, 0, 0, 0, 0,
  0, 0, 0, 0, 0, 0, 0, 0,     0, 0, 0, 0, 0, 0, 0, 0,
  0, 0, 0, 0, 0, 0, 0, 0,     0, 0, 0, 0, 0, 0, 0, 0,
  0, 0, 0, 0, 0, 0, 0, 0,     0, 0, 0, 0, 0, 0, 0, 0,
  0, 0, 0, 0, 0, 0, 0, 0,     0, 0, 0, 0, 0, 0, 0, 0,
};
#define ISALNUM(x)  (!isBoundary[(x)&0xff])

/*
** Compile a search pattern
*/
Search *search_init(const char *zPattern){
  int nPattern = strlen(zPattern);
  Search *p;
  char *z;
  int i;

  p = fossil_malloc( nPattern + sizeof(*p) + 1);
  z = (char*)&p[1];
  memcpy(z, zPattern, nPattern+1);
  memset(p, 0, sizeof(*p));
  while( *z && p->nTerm<SEARCH_MAX_TERM ){
    while( *z && !ISALNUM(*z) ){ z++; }
    if( *z==0 ) break;
    p->a[p->nTerm].z = z;
    for(i=1; ISALNUM(z[i]); i++){}
    p->a[p->nTerm].n = i;
    z += i;
    p->nTerm++;
  }
  return p;
}


/*
** Destroy a search context.
*/
void search_end(Search *p){
  free(p);
}

/*
** Append n bytes of text to snippet zTxt.  Encode the text appropriately.
*/
static void snippet_text_append(
  Search *p,             /* The search context */
  Blob *pSnip,           /* Append to this snippet */
  const char *zTxt,      /* Text to append */
  int n                  /* How many bytes to append */
){
  if( p->fSrchFlg & SRCHFLG_HTML ){
    blob_appendf(pSnip, "%.*h", n, zTxt);
  }else{
    blob_append(pSnip, zTxt, n);
  }
}

/*
** Compare a search pattern against one or more input strings which
** collectively comprise a document.  Return a match score.  Optionally
** also return a "snippet".
**
** Scoring:
**   *  All terms must match at least once or the score is zero

**   *  One point for each matching term
**   *  Extra points if consecutive words of the pattern are consecutive
**      in the document
*/
static int search_score(
  Search *p,              /* Search pattern and flags */
  int nDoc,               /* Number of strings in this document */
  const char **azDoc,     /* Text of each string */
  Blob *pSnip             /* If not NULL: Write a snippet here */
){
  int score;                         /* Final score */
  int i;                             /* Offset into current document */
  int ii;                            /* Loop counter */
  int j;                             /* Loop over search terms */
  int k;                             /* Loop over prior terms */
  int iWord = 0;                     /* Current word number */
  int iDoc;                          /* Current document number */
  int wantGap = 0;                   /* True if a zMarkGap is wanted */
  const char *zDoc;                  /* Current document text */

  const int CTX = 50;                /* Amount of snippet context */
  int anMatch[SEARCH_MAX_TERM];      /* Number of terms in best match */
  int aiBestDoc[SEARCH_MAX_TERM];    /* Document containing best match */
  int aiBestOfst[SEARCH_MAX_TERM];   /* Byte offset to start of best match */
  int aiLastDoc[SEARCH_MAX_TERM];    /* Document containing most recent match */
  int aiLastOfst[SEARCH_MAX_TERM];   /* Byte offset to the most recent match */
  int aiWordIdx[SEARCH_MAX_TERM];    /* Word index of most recent match */

  memset(anMatch, 0, sizeof(anMatch));
  memset(aiWordIdx, 0xff, sizeof(aiWordIdx));
  for(iDoc=0; iDoc<nDoc; iDoc++){
    zDoc = azDoc[iDoc];
    if( zDoc==0 ) continue;
    iWord++;
    for(i=0; zDoc[i]; i++){
      if( !ISALNUM(zDoc[i]) ) continue;
      iWord++;
      for(j=0; j<p->nTerm; j++){
        int n = p->a[j].n;
        if( sqlite3_strnicmp(p->a[j].z, &zDoc[i], n)==0
         && (!ISALNUM(zDoc[i+n]) || p->a[j].z[n]=='*')
        ){
          aiWordIdx[j] = iWord;
          aiLastDoc[j] = iDoc;
          aiLastOfst[j] = i;
          for(k=1; j-k>=0 && anMatch[j-k] && aiWordIdx[j-k]==iWord-k; k++){}
          for(ii=0; ii<k; ii++){
            if( anMatch[j-ii]<k ){
              anMatch[j-ii] = k;
              aiBestDoc[j-ii] = aiLastDoc[j-ii];
              aiBestOfst[j-ii] = aiLastOfst[j-ii];
            }
          }
          break;
        }
      }
      while( ISALNUM(zDoc[i]) ){ i++; }
    }
  }

  /* Finished search all documents.
  ** Every term must be seen or else the score is zero 
  */
  score = 1;
  for(j=0; j<p->nTerm; j++) score *= anMatch[j];
  if( score==0 || pSnip==0 ) return score;


  /* Prepare a snippet that describes the matching text.
  */
  blob_init(pSnip, 0, 0);

  while(1){
    int iOfst;
    int iTail;
    int iBest;
    for(ii=0; ii<p->nTerm && anMatch[ii]==0; ii++){}
    if( ii>=p->nTerm ) break;  /* This is where the loop exits */
    iBest = ii;
    iDoc = aiBestDoc[ii];
    iOfst = aiBestOfst[ii];
    for(; ii<p->nTerm; ii++){
      if( anMatch[ii]==0 ) continue;
      if( aiBestDoc[ii]>iDoc ) continue;
      if( aiBestOfst[ii]>iOfst ) continue;
      iDoc = aiBestDoc[ii];
      iOfst = aiBestOfst[ii];
      iBest = ii;
    }
    iTail = iOfst + p->a[iBest].n;
    anMatch[iBest] = 0;
    for(ii=0; ii<p->nTerm; ii++){
      if( anMatch[ii]==0 ) continue;
      if( aiBestDoc[ii]!=iDoc ) continue;
      if( aiBestOfst[ii]<=iTail+CTX*2 ){
        if( iTail<aiBestOfst[ii]+p->a[ii].n ){
          iTail = aiBestOfst[ii]+p->a[ii].n;
        }
        anMatch[ii] = 0;
        ii = -1;
        continue;
      }
    }
    zDoc = azDoc[iDoc];
    iOfst -= CTX;
    if( iOfst<0 ) iOfst = 0;
    while( iOfst>0 && ISALNUM(zDoc[iOfst-1]) ) iOfst--;
    while( zDoc[iOfst] && !ISALNUM(zDoc[iOfst]) ) iOfst++;
    for(ii=0; ii<CTX && zDoc[iTail]; ii++, iTail++){}
    while( ISALNUM(zDoc[iTail]) ) iTail++;
    if( iOfst>0 || wantGap ) blob_append(pSnip, p->zMarkGap, -1);
    wantGap = zDoc[iTail]!=0;
    zDoc += iOfst;
    iTail -= iOfst;

    /* Add a snippet segment using characters iOfst..iOfst+iTail from zDoc */
    for(i=0; i<iTail; i++){
      if( !ISALNUM(zDoc[i]) ) continue;
      for(j=0; j<p->nTerm; j++){
        int n = p->a[j].n;
        if( sqlite3_strnicmp(p->a[j].z, &zDoc[i], n)==0
         && (!ISALNUM(zDoc[i+n]) || p->a[j].z[n]=='*')
        ){
          snippet_text_append(p, pSnip, zDoc, i);
          zDoc += i;
          iTail -= i;

          blob_append(pSnip, p->zMarkBegin, -1);
          if( p->a[j].z[n]=='*' ){

            while( ISALNUM(zDoc[n]) ) n++;
          }
          snippet_text_append(p, pSnip, zDoc, n);
          zDoc += n;
          iTail -= n;
          blob_append(pSnip, p->zMarkEnd, -1);
          i = -1;
          break;
        } /* end-if */
      } /* end for(j) */
      if( j<p->nTerm ){
        while( ISALNUM(zDoc[i]) && i<iTail ){ i++; }
      }
    } /* end for(i) */
    if( iTail>0 ) snippet_text_append(p, pSnip, zDoc, iTail);
  }


  if( wantGap ) blob_append(pSnip, p->zMarkGap, -1);
  return score;
}

/*
** COMMAND: test-snippet
**
** Usage: fossil test-snippet SEARCHSTRING FILE1 FILE2 ... 
*/
void test_snippet_cmd(void){
  Search *p;
  int i;
  Blob x;
  Blob snip;
  int score;
  char *zDoc;
  if( g.argc<4 ) usage("SEARCHSTRING FILE1...");
  p = search_init(g.argv[2]);
  p->zMarkBegin = "[[";
  p->zMarkEnd = "]]";
  p->zMarkGap = " ... ";
  for(i=3; i<g.argc; i++){
    blob_read_from_file(&x, g.argv[i]);
    zDoc = blob_str(&x);
    score = search_score(p, 1, (const char**)&zDoc, &snip);
    fossil_print("%s: %d\n", g.argv[i], score);
    blob_reset(&x);
    if( score ){
      fossil_print("%.78c\n%s\n%.78c\n\n", '=', blob_str(&snip), '=');
      blob_reset(&snip);
    }
  }    

}

/*
** This is an SQLite function that scores its input using
** a pre-computed pattern.
*/
static void search_score_sqlfunc(
  sqlite3_context *context,
  int argc,
  sqlite3_value **argv
){
  Search *p = (Search*)sqlite3_user_data(context);
  const char **azDoc;
  int score;
  int i;

  azDoc = fossil_malloc( sizeof(const char*)*(argc+1) );
  for(i=0; i<argc; i++) azDoc[i] = (const char*)sqlite3_value_text(argv[i]);
  score = search_score(p, argc, azDoc, 0);
  fossil_free((void *)azDoc);
  sqlite3_result_int(context, score);
}

/*
** Register the "score()" SQL function to score its input text
** using the given Search object.  Once this function is registered,