//
// Created by Tyler on 10/6/20.
//

#include "assignment-hash.hpp"
#include <ndn-cxx/util/sha256.hpp>

namespace ndn {
namespace ndncert {

_LOG_INIT(ndncert.assignment.hash);

NDNCERT_REGISTER_FUNCFACTORY(AssignmentHash, "hash");

AssignmentHash::AssignmentHash()
    : NameAssignmentFuncFactory("hash")
{
}

NameAssignmentFunc
AssignmentHash::getFunction(const std::string &factoryParam) {
    std::list<std::string> paramList;
    size_t index = 0, startIndex = 0;
    while ((index = factoryParam.find("/", startIndex)) != std::string::npos) {
        auto component = factoryParam.substr(startIndex, index - startIndex);
        if (!component.empty()) {
            paramList.push_back(component);
        }
        startIndex = index + 1;
    }
    if (startIndex != factoryParam.size()) {
        paramList.push_back(factoryParam.substr(startIndex));
    }
    return [paramList](const std::vector<std::tuple<std::string, std::string>> params){
        if (params.size() > paramList.size() * 8) { // might be attack
            BOOST_THROW_EXCEPTION(std::runtime_error("Too many extra parameters given"));
        }
        std::map<std::string, std::string> paramMap;
        for (const auto& param : params) {
            paramMap[std::get<0>(param)] = std::get<1>(param);
        }

        //construct name
        PartialName name;
        for (const auto& field : paramList) {
            auto it = paramMap.find(field);
            if (it == paramMap.end()) {
                return std::vector<PartialName>();
            } else {
                name.append(it->second);
            }
        }
        std::vector<PartialName> nameList;
        util::Sha256 digest;
        digest << name.wireEncode();
        nameList.emplace_back(digest.toString());

        return nameList;
    };
}

}
}