/*****************************************************************************

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*****************************************************************************/

/** @file fts/fts0plugin.cc
 Full Text Search plugin support.

 Created 2013/06/04 Shaohua Wang
 ***********************************************************************/

#include "fts0plugin.h"
#include "ft_global.h"
#include "fts0ast.h"
#include "fts0tokenize.h"
#include "mysql/plugin.h"

/** FTS default parser init
 @return 0 */
static int fts_default_parser_init(MYSQL_FTPARSER_PARAM *param [
    [maybe_unused]]) /*!< in: plugin parser param */
{
  return (0);
}

/** FTS default parser deinit
 @return 0 */
static int fts_default_parser_deinit(MYSQL_FTPARSER_PARAM *param [
    [maybe_unused]]) /*!< in: plugin parser param */
{
  return (0);
}

/** FTS default parser parse from ft_static.c in MYISAM.
 @return 0 if parse successfully, or return non-zero */
static int fts_default_parser_parse(
    MYSQL_FTPARSER_PARAM *param) /*!< in: plugin parser param */
{
  return (param->mysql_parse(param, param->doc, param->length));
}

/* FTS default parser from ft_static.c in MYISAM. */
struct st_mysql_ftparser fts_default_parser = {
    MYSQL_FTPARSER_INTERFACE_VERSION, fts_default_parser_parse,
    fts_default_parser_init, fts_default_parser_deinit};

/** Get a operator node from token boolean info
 @return node */
static fts_ast_node_t *fts_query_get_oper_node(
    MYSQL_FTPARSER_BOOLEAN_INFO *info, /*!< in: token info */
    fts_ast_state_t *state)            /*!< in/out: query parse state*/
{
  fts_ast_node_t *oper_node = nullptr;

  if (info->yesno > 0) {
    oper_node = fts_ast_create_node_oper(state, FTS_EXIST);
  } else if (info->yesno < 0) {
    oper_node = fts_ast_create_node_oper(state, FTS_IGNORE);
  } else if (info->weight_adjust > 0) {
    oper_node = fts_ast_create_node_oper(state, FTS_INCR_RATING);
  } else if (info->weight_adjust < 0) {
    oper_node = fts_ast_create_node_oper(state, FTS_DECR_RATING);
  } else if (info->wasign > 0) {
    oper_node = fts_ast_create_node_oper(state, FTS_NEGATE);
  }

  return (oper_node);
}

/** FTS plugin parser 'myql_add_word' callback function for query parse.
 Refer to 'MYSQL_FTPARSER_PARAM' for more detail.
 Note:
 a. Parse logic refers to 'ftb_query_add_word' from ft_boolean_search.c in
 MYISAM; b. Parse node or tree refers to fts0pars.y.
 @return 0 if add successfully, or return non-zero. */
static int fts_query_add_word_for_parser(
    MYSQL_FTPARSER_PARAM *param,       /*!< in: parser param */
    char *word,                        /*!< in: token */
    int word_len,                      /*!< in: token length */
    MYSQL_FTPARSER_BOOLEAN_INFO *info) /*!< in: token info */
{
  fts_ast_state_t *state = static_cast<fts_ast_state_t *>(param->mysql_ftparam);
  fts_ast_node_t *cur_node = state->cur_node;
  fts_ast_node_t *oper_node = nullptr;
  fts_ast_node_t *term_node = nullptr;
  fts_ast_node_t *node = nullptr;

  switch (info->type) {
    case FT_TOKEN_STOPWORD:
      /* We only handler stopword in phrase */
      if (cur_node->type != FTS_AST_PARSER_PHRASE_LIST) {
        break;
      }
      [[fallthrough]];

    case FT_TOKEN_WORD:
      term_node = fts_ast_create_node_term_for_parser(state, word, word_len);

      if (info->trunc) {
        fts_ast_term_set_wildcard(term_node);
      }

      if (cur_node->type == FTS_AST_PARSER_PHRASE_LIST) {
        /* Ignore operator inside phrase */
        fts_ast_add_node(cur_node, term_node);
      } else {
        ut_ad(cur_node->type == FTS_AST_LIST ||
              cur_node->type == FTS_AST_SUBEXP_LIST);
        oper_node = fts_query_get_oper_node(info, state);

        if (oper_node) {
          node = fts_ast_create_node_list(state, oper_node);
          fts_ast_add_node(node, term_node);
          fts_ast_add_node(cur_node, node);
        } else {
          fts_ast_add_node(cur_node, term_node);
        }
      }

      break;

    case FT_TOKEN_LEFT_PAREN:
      /* Check parse error */
      if (cur_node->type != FTS_AST_LIST &&
          cur_node->type != FTS_AST_SUBEXP_LIST) {
        return (1);
      }

      /* Set operator */
      oper_node = fts_query_get_oper_node(info, state);
      if (oper_node != nullptr) {
        node = fts_ast_create_node_list(state, oper_node);
        fts_ast_add_node(cur_node, node);
        node->go_up = true;
        node->up_node = cur_node;
        cur_node = node;
      }

      if (info->quot) {
        /* Phrase node */
        node = fts_ast_create_node_phrase_list(state);
      } else {
        /* Subexp list node */
        node = fts_ast_create_node_subexp_list(state, nullptr);
      }

      fts_ast_add_node(cur_node, node);

      node->up_node = cur_node;
      state->cur_node = node;
      state->depth += 1;

      break;

    case FT_TOKEN_RIGHT_PAREN:
      info->quot = nullptr;

      if (cur_node->up_node != nullptr) {
        cur_node = cur_node->up_node;

        if (cur_node->go_up) {
          ut_a(cur_node->up_node && !(cur_node->up_node->go_up));
          cur_node = cur_node->up_node;
        }
      }

      state->cur_node = cur_node;

      if (state->depth > 0) {
        state->depth--;
      } else {
        /* Parentheses mismatch */
        return (1);
      }

      break;

    case FT_TOKEN_EOF:
    default:
      break;
  }

  return (0);
}

/** FTS plugin parser 'myql_parser' callback function for query parse.
 Refer to 'MYSQL_FTPARSER_PARAM' for more detail.
 @return 0 if parse successfully */
static int fts_parse_query_internal(
    MYSQL_FTPARSER_PARAM *param, /*!< in: parser param */
    char *query,                 /*!< in: query string */
    int len)                     /*!< in: query length */
{
  MYSQL_FTPARSER_BOOLEAN_INFO info;
  const CHARSET_INFO *cs = param->cs;
  uchar **start = reinterpret_cast<uchar **>(&query);
  uchar *end = reinterpret_cast<uchar *>(query + len);
  FT_WORD w = {nullptr, 0, 0};

  info.prev = ' ';
  info.quot = nullptr;
  memset(&w, 0, sizeof(w));
  /* Note: We don't handle simple parser mode here,
  but user supplied plugin parser should handler it. */
  while (fts_get_word(cs, start, end, &w, &info)) {
    int ret = param->mysql_add_word(param, reinterpret_cast<char *>(w.pos),
                                    w.len, &info);
    if (ret) {
      return (ret);
    }
  }

  return (0);
}

/** fts parse query by plugin parser.
 @return 0 if parse successfully, or return non-zero. */
int fts_parse_by_parser(bool mode,        /*!< in: parse boolean mode */
                        uchar *query_str, /*!< in: query string */
                        ulint query_len,  /*!< in: query string length */
                        st_mysql_ftparser *parser, /*!< in: fts plugin parser */
                        fts_ast_state_t *state)    /*!< in/out: parser state */
{
  MYSQL_FTPARSER_PARAM param;
  int ret;

  ut_ad(parser);

  /* Initial parser param */
  param.mysql_parse = fts_parse_query_internal;
  param.mysql_add_word = fts_query_add_word_for_parser;
  param.mysql_ftparam = static_cast<void *>(state);
  param.cs = state->charset;
  param.doc = reinterpret_cast<char *>(query_str);
  param.length = static_cast<int>(query_len);
  param.flags = 0;
  param.mode =
      mode ? MYSQL_FTPARSER_FULL_BOOLEAN_INFO : MYSQL_FTPARSER_SIMPLE_MODE;

  PARSER_INIT(parser, &param);
  ret = parser->parse(&param);
  PARSER_DEINIT(parser, &param);

  return (ret | state->depth);
}
