// Copyright Contributors to the DNF5 project.
// Copyright Contributors to the libdnf project.
// SPDX-License-Identifier: LGPL-2.1-or-later
//
// This file is part of libdnf: https://github.com/rpm-software-management/libdnf/
//
// Libdnf is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 2.1 of the License, or
// (at your option) any later version.
//
// Libdnf 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 Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with libdnf.  If not, see <https://www.gnu.org/licenses/>.

#include "reldep_parser.hpp"

#include "utils/regex.hpp"

#include <regex>
#include <string>


namespace libdnf5::solv {

// Avoid using the \s and \S patterns here as they are GNU extensions and aren't portable.
static const std::regex RELDEP_REGEX("^([^[:space:]]*)[[:space:]]*(<=|>=|<|>|=)?[[:space:]]*([^[:space:]]*)$");

static bool set_cmp_type(libdnf5::rpm::Reldep::CmpType * cmp_type, std::string cmp_type_string, long int length) {
    if (length == 2) {
        // The second character must be '='
        if (cmp_type_string[1] != '=') {
            return false;
        }
        if (cmp_type_string[0] == '<') {
            *cmp_type = libdnf5::rpm::Reldep::CmpType::LTE;
            return true;
        } else if (cmp_type_string[0] == '>') {
            *cmp_type = libdnf5::rpm::Reldep::CmpType::GTE;
            return true;
        } else {
            return false;
        }
    } else if (length == 1) {
        if (cmp_type_string[0] == '>') {
            *cmp_type = libdnf5::rpm::Reldep::CmpType::GT;
            return true;
        } else if (cmp_type_string[0] == '<') {
            *cmp_type = libdnf5::rpm::Reldep::CmpType::LT;
            return true;
        } else if (cmp_type_string[0] == '=') {
            *cmp_type = libdnf5::rpm::Reldep::CmpType::EQ;
            return true;
        } else {
            return false;
        }
    }
    return false;
}


bool ReldepParser::parse(const std::string & reldep) {
    enum { NAME = 1, CMP_TYPE = 2, EVR = 3 };
    std::smatch match;
    if (reldep.length() > MAX_STRING_LENGTH_FOR_REGEX_MATCH) {
        // GCC std::regex_match() exhausts a stack on very long strings.
        return false;
    }
    if (!std::regex_match(reldep, match, RELDEP_REGEX)) {
        return false;
    } else {
        std::ssub_match cmp_type_sub_match = match[CMP_TYPE];
        std::ssub_match evr_sub_match = match[EVR];
        auto cmp_type_length = cmp_type_sub_match.length();
        auto evr_length = evr_sub_match.length();
        // Only evr and cmp_type together or only name is a valid reldep
        if ((cmp_type_length && evr_length) || (!cmp_type_length && !evr_length)) {
            name = match[NAME].str();
            if (cmp_type_length) {
                evr = evr_sub_match.str();
                auto cmp_type_string = cmp_type_sub_match.str();
                return set_cmp_type(&cmp_type, cmp_type_string, cmp_type_length);
            } else {
                cmp_type = libdnf5::rpm::Reldep::CmpType::NONE;
                evr.clear();
                return true;
            }
        } else {
            return false;
        }
    }
}

}  // namespace libdnf5::solv
