// Copyright 2023 PingCAP, Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#include <Common/typeid_cast.h>
#include <Parsers/ASTDropQuery.h>
#include <Parsers/ASTIdentifier.h>
#include <Parsers/CommonParsers.h>
#include <Parsers/ParserDropQuery.h>


namespace DB
{
bool ParserDropQuery::parseImpl(Pos & pos, ASTPtr & node, Expected & expected)
{
    ParserKeyword s_drop("DROP");
    ParserKeyword s_detach("DETACH");
    ParserKeyword s_temporary("TEMPORARY");
    ParserKeyword s_table("TABLE");
    ParserKeyword s_database("DATABASE");
    ParserToken s_dot(TokenType::Dot);
    ParserKeyword s_if_exists("IF EXISTS");
    ParserIdentifier name_p;

    ASTPtr database;
    ASTPtr table;
    bool detach = false;
    bool if_exists = false;
    bool temporary = false;

    if (!s_drop.ignore(pos, expected))
    {
        if (s_detach.ignore(pos, expected))
            detach = true;
        else
            return false;
    }

    if (s_database.ignore(pos, expected))
    {
        if (s_if_exists.ignore(pos, expected))
            if_exists = true;

        if (!name_p.parse(pos, database, expected))
            return false;
    }
    else
    {
        if (s_temporary.ignore(pos, expected))
            temporary = true;

        if (!s_table.ignore(pos, expected))
            return false;

        if (s_if_exists.ignore(pos, expected))
            if_exists = true;

        if (!name_p.parse(pos, table, expected))
            return false;

        if (s_dot.ignore(pos, expected))
        {
            database = table;
            if (!name_p.parse(pos, table, expected))
                return false;
        }
    }

    auto query = std::make_shared<ASTDropQuery>();
    node = query;

    query->detach = detach;
    query->if_exists = if_exists;
    query->temporary = temporary;
    if (database)
        query->database = typeid_cast<ASTIdentifier &>(*database).name;
    if (table)
        query->table = typeid_cast<ASTIdentifier &>(*table).name;

    return true;
}


} // namespace DB