/* Copyright (C) 2006 MySQL AB & MySQL Finland AB & TCX DataKonsult AB
   Copyright (c) 2020, MariaDB Corporation.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; version 2 of the License.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1335 USA */

/* Written by Sergei A. Golubchik, who has a shared copyright to this code */

#include "ma_ftdefs.h"

typedef struct st_maria_ft_docstat {
  FT_WORD *list;
  uint uniq;
  double sum;
} FT_DOCSTAT;


typedef struct st_my_maria_ft_parser_param
{
  TREE *wtree;
  MEM_ROOT *mem_root;
} MY_FT_PARSER_PARAM;


static int FT_WORD_cmp(CHARSET_INFO* cs, FT_WORD *w1, FT_WORD *w2)
{
  return ha_compare_text(cs, (uchar*) w1->pos, w1->len,
                         (uchar*) w2->pos, w2->len, 0);
}

static int walk_and_copy(FT_WORD *word,uint32 count,FT_DOCSTAT *docstat)
{
    word->weight=LWS_IN_USE;
    docstat->sum+=word->weight;
    memcpy((docstat->list)++, word, sizeof(FT_WORD));
    return 0;
}

/* transforms tree of words into the array, applying normalization */

FT_WORD * maria_ft_linearize(TREE *wtree, MEM_ROOT *mem_root)
{
  FT_WORD *wlist,*p;
  FT_DOCSTAT docstat;
  DBUG_ENTER("maria_ft_linearize");

  if ((wlist=(FT_WORD *) alloc_root(mem_root, sizeof(FT_WORD)*
                                    (1+wtree->elements_in_tree))))
  {
    docstat.list=wlist;
    docstat.uniq=wtree->elements_in_tree;
    docstat.sum=0;
    tree_walk(wtree,(tree_walk_action)&walk_and_copy,&docstat,left_root_right);
  }
  delete_tree(wtree, 0);
  if (!wlist)
    DBUG_RETURN(NULL);

  docstat.list->pos=NULL;

  for (p=wlist;p->pos;p++)
  {
    p->weight=PRENORM_IN_USE;
  }

  for (p=wlist;p->pos;p++)
  {
    p->weight/=NORM_IN_USE;
  }

  DBUG_RETURN(wlist);
}

/*
  RETURN VALUE
  0 - eof
  1 - word found
  2 - left bracket
  3 - right bracket
  4 - stopword found
*/
uchar maria_ft_get_word(CHARSET_INFO *cs, const uchar **start,
                        const uchar *end,
                        FT_WORD *word, MYSQL_FTPARSER_BOOLEAN_INFO *param)
{
  const uchar *doc= *start;
  int ctype;
  uint mwc, length;
  int mbl;

  param->yesno=(FTB_YES==' ') ? 1 : (param->quot != 0);
  param->weight_adjust= param->wasign= 0;
  param->type= FT_TOKEN_EOF;

  while (doc<end)
  {
    for (; doc < end; doc+= (mbl > 0 ? mbl : (mbl < 0 ? -mbl : 1)))
    {
      mbl= my_ci_ctype(cs, &ctype, doc, end);
      if (true_word_char(ctype, *doc))
        break;
      if (*doc == FTB_RQUOT && param->quot)
      {
        param->quot= (char *) doc;
        *start=doc+1;
        param->type= FT_TOKEN_RIGHT_PAREN;
        goto ret;
      }
      if (!param->quot)
      {
        if (*doc == FTB_LBR || *doc == FTB_RBR || *doc == FTB_LQUOT)
        {
          /* param->prev=' '; */
          *start=doc+1;
          if (*doc == FTB_LQUOT)
            param->quot= (char *) *start;
          param->type= (*doc == FTB_RBR ? FT_TOKEN_RIGHT_PAREN : FT_TOKEN_LEFT_PAREN);
          goto ret;
        }
        if (param->prev == ' ')
        {
          if (*doc == FTB_YES ) { param->yesno=+1;    continue; } else
          if (*doc == FTB_EGAL) { param->yesno= 0;    continue; } else
          if (*doc == FTB_NO  ) { param->yesno=-1;    continue; } else
          if (*doc == FTB_INC ) { param->weight_adjust++; continue; } else
          if (*doc == FTB_DEC ) { param->weight_adjust--; continue; } else
          if (*doc == FTB_NEG ) { param->wasign= !param->wasign; continue; }
        }
      }
      param->prev=*doc;
      param->yesno=(FTB_YES==' ') ? 1 : (param->quot != 0);
      param->weight_adjust= param->wasign= 0;
    }

    mwc=length=0;
    for (word->pos= doc; doc < end; length++,
         doc+= (mbl > 0 ? mbl : (mbl < 0 ? -mbl : 1)))
    {
      mbl= my_ci_ctype(cs, &ctype, doc, end);
      if (true_word_char(ctype, *doc))
        mwc=0;
      else if (!misc_word_char(*doc) || mwc)
        break;
      else
        mwc++;
    }
    param->prev='A'; /* be sure *prev is true_word_char */
    word->len= (uint)(doc-word->pos) - mwc;
    if ((param->trunc=(doc<end && *doc == FTB_TRUNC)))
      doc++;

    if (((length >= ft_min_word_len && !is_stopword((char *) word->pos,
                                                    word->len))
         || param->trunc) && length < ft_max_word_len)
    {
      *start=doc;
      param->type= FT_TOKEN_WORD;
      goto ret;
    }
    else if (length) /* make sure length > 0 (if start contains spaces only) */
    {
      *start= doc;
      param->type= FT_TOKEN_STOPWORD;
      goto ret;
    }
  }
  if (param->quot)
  {
    param->quot= (char *)(*start= doc);
    param->type= 3; /* FT_RBR */
    goto ret;
  }
ret:
  return param->type;
}

uchar maria_ft_simple_get_word(CHARSET_INFO *cs, uchar **start,
                               const uchar *end, FT_WORD *word,
                               my_bool skip_stopwords)
{
  uchar *doc= *start;
  uint mwc, length;
  int ctype, mbl;
  DBUG_ENTER("maria_ft_simple_get_word");

  do
  {
    for (;; doc+= (mbl > 0 ? mbl : (mbl < 0 ? -mbl : 1)))
    {
      if (doc >= end)
        DBUG_RETURN(0);
      mbl= my_ci_ctype(cs, &ctype, doc, end);
      if (true_word_char(ctype, *doc))
        break;
    }

    mwc= length= 0;
    for (word->pos= doc; doc < end; length++,
         doc+= (mbl > 0 ? mbl : (mbl < 0 ? -mbl : 1)))
    {
      mbl= my_ci_ctype(cs, &ctype, doc, end);
      if (true_word_char(ctype, *doc))
        mwc= 0;
      else if (!misc_word_char(*doc) || mwc)
        break;
      else
        mwc++;
    }

    word->len= (uint)(doc-word->pos) - mwc;

    if (skip_stopwords == FALSE ||
        (length >= ft_min_word_len && length < ft_max_word_len &&
         !is_stopword((char *) word->pos, word->len)))
    {
      *start= doc;
      DBUG_RETURN(1);
    }
  } while (doc < end);
  DBUG_RETURN(0);
}

void maria_ft_parse_init(TREE *wtree, CHARSET_INFO *cs)
{
  DBUG_ENTER("maria_ft_parse_init");
  if (!is_tree_inited(wtree))
    init_tree(wtree,0,0,sizeof(FT_WORD),(qsort_cmp2)&FT_WORD_cmp, NULL,
              (void*) cs, MYF(0));
  DBUG_VOID_RETURN;
}


static int maria_ft_add_word(MYSQL_FTPARSER_PARAM *param,
                             const char *word, int word_len,
                             MYSQL_FTPARSER_BOOLEAN_INFO *boolean_info
                             __attribute__((unused)))
{
  TREE *wtree;
  FT_WORD w;
  MY_FT_PARSER_PARAM *ft_param=param->mysql_ftparam;
  DBUG_ENTER("maria_ft_add_word");
  wtree= ft_param->wtree;
  if (param->flags & MYSQL_FTFLAGS_NEED_COPY)
  {
    uchar *ptr;
    DBUG_ASSERT(wtree->with_delete == 0);
    ptr= (uchar *)alloc_root(ft_param->mem_root, word_len);
    memcpy(ptr, word, word_len);
    w.pos= ptr;
  }
  else
    w.pos= (uchar*) word;
  w.len= word_len;
  if (!tree_insert(wtree, &w, 0, wtree->custom_arg))
  {
    delete_tree(wtree, 0);
    DBUG_RETURN(1);
  }
  DBUG_RETURN(0);
}


static int maria_ft_parse_internal(MYSQL_FTPARSER_PARAM *param,
                                   const char *doc_arg,
                                   int doc_len)
{
  uchar *doc= (uchar*) doc_arg;
  uchar *end= doc + doc_len;
  MY_FT_PARSER_PARAM *ft_param=param->mysql_ftparam;
  TREE *wtree= ft_param->wtree;
  FT_WORD w;
  DBUG_ENTER("maria_ft_parse_internal");

  while (maria_ft_simple_get_word(wtree->custom_arg, &doc, end, &w, TRUE))
    if (param->mysql_add_word(param, (char*)w.pos, w.len, 0))
      DBUG_RETURN(1);
  DBUG_RETURN(0);
}


int maria_ft_parse(TREE *wtree, uchar *doc, int doclen,
                   struct st_mysql_ftparser *parser,
                   MYSQL_FTPARSER_PARAM *param, MEM_ROOT *mem_root)
{
  MY_FT_PARSER_PARAM my_param;
  DBUG_ENTER("maria_ft_parse");
  DBUG_ASSERT(parser);
  my_param.wtree= wtree;
  my_param.mem_root= mem_root;

  param->mysql_parse= maria_ft_parse_internal;
  param->mysql_add_word= maria_ft_add_word;
  param->mysql_ftparam= &my_param;
  param->cs= wtree->custom_arg;
  param->doc= (char*)doc;
  param->length= doclen;
  param->mode= MYSQL_FTPARSER_SIMPLE_MODE;
  DBUG_RETURN(parser->parse(param));
}


#define MAX_PARAM_NR 2

MYSQL_FTPARSER_PARAM* maria_ftparser_alloc_param(MARIA_HA *info)
{
  if (!info->ftparser_param)
  {
    /* 
.     info->ftparser_param can not be zero after the initialization,
      because it always includes built-in fulltext parser. And built-in
      parser can be called even if the table has no fulltext indexes and
      no varchar/text fields.

      ftb_find_relevance... parser (ftb_find_relevance_parse,
      ftb_find_relevance_add_word) calls ftb_check_phrase... parser
      (ftb_check_phrase_internal, ftb_phrase_add_word). Thus MAX_PARAM_NR=2.
    */
    info->ftparser_param= (MYSQL_FTPARSER_PARAM *)
      my_malloc(PSI_INSTRUMENT_ME, MAX_PARAM_NR * sizeof(MYSQL_FTPARSER_PARAM) *
                info->s->ftkeys, MYF(MY_WME | MY_ZEROFILL));
    init_alloc_root(PSI_INSTRUMENT_ME, &info->ft_memroot,
                    FTPARSER_MEMROOT_ALLOC_SIZE, 0, MYF(0));
  }
  return info->ftparser_param;
}


MYSQL_FTPARSER_PARAM *maria_ftparser_call_initializer(MARIA_HA *info,
                                                      uint keynr, uint paramnr)
{
  uint32 ftparser_nr;
  struct st_mysql_ftparser *parser;
  
  if (!maria_ftparser_alloc_param(info))
    return 0;

  if (keynr == NO_SUCH_KEY)
  {
    ftparser_nr= 0;
    parser= &ft_default_parser;
  }
  else
  {
    ftparser_nr= info->s->keyinfo[keynr].ftkey_nr;
    parser= info->s->keyinfo[keynr].parser;
  }
  DBUG_ASSERT(paramnr < MAX_PARAM_NR);
  ftparser_nr= ftparser_nr*MAX_PARAM_NR + paramnr;
  if (! info->ftparser_param[ftparser_nr].mysql_add_word)
  {
    /* Note, that mysql_add_word is used here as a flag:
       mysql_add_word == 0 - parser is not initialized
       mysql_add_word != 0 - parser is initialized, or no
                             initialization needed. */
    info->ftparser_param[ftparser_nr].mysql_add_word=
      (int (*)(struct st_mysql_ftparser_param *, const char *,
               int, MYSQL_FTPARSER_BOOLEAN_INFO *)) 1;
    if (parser->init && parser->init(&info->ftparser_param[ftparser_nr]))
      return 0;
  }
  return &info->ftparser_param[ftparser_nr];
}


void maria_ftparser_call_deinitializer(MARIA_HA *info)
{
  uint i, j, keys= info->s->state.header.keys;
  free_root(&info->ft_memroot, MYF(0));
  if (! info->ftparser_param)
    return;
  for (i= 0; i < keys; i++)
  {
    MARIA_KEYDEF *keyinfo= &info->s->keyinfo[i];
    for (j=0; j < MAX_PARAM_NR; j++)
    {
      MYSQL_FTPARSER_PARAM *ftparser_param=
        &info->ftparser_param[keyinfo->ftkey_nr*MAX_PARAM_NR + j];
      if (keyinfo->flag & HA_FULLTEXT && ftparser_param->mysql_add_word)
      {
        if (keyinfo->parser->deinit)
          keyinfo->parser->deinit(ftparser_param);
        ftparser_param->mysql_add_word= 0;
      }
      else
        break;
    }
  }
}