#include <Parsers/parseUserName.h>
#include <Parsers/parseIdentifierOrStringLiteral.h>
#include <Parsers/CommonParsers.h>
#include <boost/algorithm/string.hpp>

namespace DB
{
namespace
{
    bool parseUserNameImpl(IParser::Pos & pos, Expected & expected, String & user_name, String * host_like_pattern)
    {
        String name;
        if (!parseIdentifierOrStringLiteral(pos, expected, name))
            return false;

        boost::algorithm::trim(name);

        String pattern = "@";

        if (ParserToken{TokenType::At}.ignore(pos, expected))
        {
            if (!parseIdentifierOrStringLiteral(pos, expected, pattern))
                return false;

            boost::algorithm::trim(pattern);
        }

        if (pattern != "@")
            name += '@' + pattern;

        user_name = std::move(name);
        if (host_like_pattern)
            *host_like_pattern = std::move(pattern);
        return true;
    }
}


bool parseUserName(IParser::Pos & pos, Expected & expected, String & user_name)
{
    return parseUserNameImpl(pos, expected, user_name, nullptr);
}


bool parseUserName(IParser::Pos & pos, Expected & expected, String & user_name, String & host_like_pattern)
{
    return parseUserNameImpl(pos, expected, user_name, &host_like_pattern);
}


bool parseUserNameOrCurrentUserTag(IParser::Pos & pos, Expected & expected, String & user_name, bool & current_user)
{
    if (ParserKeyword{"CURRENT_USER"}.ignore(pos, expected) || ParserKeyword{"currentUser"}.ignore(pos, expected))
    {
        if (ParserToken{TokenType::OpeningRoundBracket}.ignore(pos, expected))
        {
            if (!ParserToken{TokenType::ClosingRoundBracket}.ignore(pos, expected))
                return false;
        }
        current_user = true;
        return true;
    }

    if (parseUserName(pos, expected, user_name))
    {
        current_user = false;
        return true;
    }

    return false;
}

}