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

Copyright (c) 2013, 2021, Oracle and/or its affiliates.

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License, version 2.0,
as published by the Free Software Foundation.

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this program; if not, write to the Free Software Foundation, Inc.,
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*****************************************************************************/

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

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

#include "fts0ast.h"
#include "fts0plugin.h"
#include "fts0tokenize.h"

#include "ft_global.h"

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

/******************************************************************//**
FTS default parser deinit
@return 0 */
static
int
fts_default_parser_deinit(
/*======================*/
	MYSQL_FTPARSER_PARAM *param)	/*!< 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 = NULL;

	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 'st_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. */
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 = NULL;
	fts_ast_node_t*	term_node = NULL;
	fts_ast_node_t*	node = NULL;

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

	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 != NULL) {
			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, NULL);
		}

		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 = 0;

		if (cur_node->up_node != NULL) {
			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 'st_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 = {NULL, 0, 0};

	info.prev = ' ';
	info.quot = 0;
	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(
/*================*/
	ibool			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);
}
