#include "streams.h"
#include <cerrno>
#include <climits>

file_stream::file_stream(const json &config, const std::size_t osize)
    : stream(osize)
    , _path(config.at("path").get<std::string>())
    , _istream(_path, std::ios::binary) {}

vec_cview file_stream::next() {
    _istream.read(reinterpret_cast<char *>(_data.data()), osize());

    if (_istream.fail()) {
        perror("stream failbit (or badbit). error state:");
        throw std::runtime_error("I/O error while reading a file " + _path);
    }
    if (_istream.eof())
        throw std::runtime_error("end of file " + _path + " reached, not enough data!");

    return make_cview(_data);
}

const_stream::const_stream(const json &config, const std::size_t osize)
    : stream(osize) {

    const std::string value = config.at("value");
    fromHex(_data, value);
    if (_data.size() != osize) {
        throw std::runtime_error(std::string("Input value length ") + std::to_string(_data.size()) +
                                 " does not match required size " + std::to_string(osize));
    }
}

void const_stream::fromHex(std::vector<value_type> &res, const std::string &hex) {
    if (hex.size() & 1) {
        throw std::runtime_error("Input length is not divisible by 2");
    }

    res.reserve(hex.size() / 2);
    for (size_t i = 0; i < hex.size(); i += 2) {
        char *endptr = nullptr;
        const auto chunk = hex.substr(i, 2);
        const char *nptr = chunk.c_str();
        errno = 0;
        auto cbyte = strtol(nptr, &endptr, 16);
        if ((cbyte == 0 && errno != 0) || cbyte == LONG_MIN || cbyte == LONG_MAX ||
            endptr - nptr < 2) {
            throw std::runtime_error(std::string("Hex decoding failed at pos ") +
                                     std::to_string(i));
        }
        res.push_back((value_type)cbyte);
    }
}

vec_cview const_stream::next() {
    return make_cview(_data);
}

single_value_stream::single_value_stream(
    const json &config,
    default_seed_source &seeder,
    std::unordered_map<std::string, std::shared_ptr<std::unique_ptr<stream>>> &pipes,
    const std::size_t osize)
    : stream(osize) {
    auto stream = make_stream(config, seeder, pipes, osize);
    vec_cview single_vector = stream->next();
    std::copy(single_vector.begin(), single_vector.end(), _data.begin());
}

vec_cview single_value_stream::next() {
    return make_cview(_data);
}

repeating_stream::repeating_stream(
    const json &config,
    default_seed_source &seeder,
    std::unordered_map<std::string, std::shared_ptr<std::unique_ptr<stream>>> &pipes,
    const std::size_t osize)
    : stream(osize)
    , _source(make_stream(config.at("source"), seeder, pipes, osize))
    , _period(unsigned(config.value("period", 0)))
    , _i(0) {}

vec_cview repeating_stream::next() {
    if (_i % _period == 0) {
        _data = _source->next().copy_to_vector();
    }
    ++_i;
    return make_cview(_data);
}

counter::counter(const std::size_t osize)
    : stream(osize) {
    std::fill(_data.begin(), _data.end(), std::numeric_limits<value_type>::min());
}

vec_cview counter::next() {
    for (value_type &value : _data) {
        if (value != std::numeric_limits<value_type>::max()) {
            ++value;
            break;
        }
        value = std::numeric_limits<value_type>::min();
    }
    return make_cview(_data);
}

random_start_counter::random_start_counter(default_seed_source &seeder, const std::size_t osize)
    : counter(osize) {
    auto stream = std::make_unique<pcg32_stream>(seeder, osize);
    vec_cview single_vector = stream->next();
    std::copy(single_vector.begin(), single_vector.end(), _data.begin());
}

template <typename Seeder>
xor_stream::xor_stream(
    const json &config,
    Seeder &&seeder,
    std::unordered_map<std::string, std::shared_ptr<std::unique_ptr<stream>>> &pipes,
    const std::size_t osize)
    : stream(osize)
    , _source(make_stream(config.at("source"), seeder, pipes, osize * 2)) {}

vec_cview xor_stream::next() {
    vec_cview in = _source->next();
    auto first1 = in.begin();
    const auto last = in.begin() + _data.size();
    auto first2 = in.begin() + _data.size();
    auto o_first = _data.begin();

    while (first1 != last) {
        *o_first++ = (*first1++ xor *first2++);
    }

    return make_cview(_data);
}

vec_cview hw_counter::next() {
    std::copy_n(_origin_data.begin(), osize(), _data.begin());
    for (const auto &pos : _cur_positions) {
        _data[pos / 8] ^= (1 << (pos % 8));
    }

    if (!combination_next()) {
        if (_increase_hw) {
            _cur_hw += 1;
        } else if (_randomize_overflow) {
            randomize(); // combination space depleted && not increasing HW.
        }

        if (_cur_hw > osize() * 8 && _increase_hw) {
            _cur_hw = 1; // reset
        }

        combination_init();
    }

    return make_cview(_data);
}

column_stream::column_stream(
    const json &config,
    default_seed_source &seeder,
    std::unordered_map<std::string, std::shared_ptr<std::unique_ptr<stream>>> &pipes,
    const std::size_t osize)
    : stream(osize)
    , _internal_bit_size(std::size_t(config.at("size")) * 8)
    , _buf(_internal_bit_size)
    , _position(0)
    , _source(make_stream(config.at("source"), seeder, pipes, _internal_bit_size / 8)) {
    for (auto &v : _buf)
        v.resize(osize);
}

vec_cview column_stream::next() {
    // regenerate the buffer
    if ((_position % _internal_bit_size) == 0) {
        _position = 0;

        // memset _buf to 0; change to STL?
        for (auto &vec : _buf)
            for (auto &val : vec)
                val = 0;

        for (std::size_t i = 0; i < osize() * 8; ++i) {
            auto vec = _source->next().data();

            // something like matrix transposition
            for (std::size_t j = 0; j < _internal_bit_size; ++j) {
                // select current bit (&), move it as least significant (>>) and then move it to the
                // position given by _i_ - which column you should store to
                _buf[j][i / 8] |= ((vec[j / 8] & (0x1 << (7 - (j % 8)))) >> (7 - (j % 8)))
                                  << (7 - (i % 8));
            }
        }
    }

    return make_cview(_buf[_position++]); // return and increment
}

column_fixed_position_stream::column_fixed_position_stream(
    const json &config,
    default_seed_source &seeder,
    std::unordered_map<std::string, std::shared_ptr<std::unique_ptr<stream>>> &pipes,
    const std::size_t osize,
    const std::size_t position)
    : stream(osize)
    , _position(position)
    , _source(make_stream(config.at("source"), seeder, pipes, std::size_t(config.at("size")))) {}

vec_cview column_fixed_position_stream::next() {
    for (auto &val : _data)
        val = 0;

    std::size_t rev_pos = 7 - (_position % 8);

    for (std::size_t i = 0; i < osize() * 8; ++i) {
        auto vec = _source->next().data();

        std::size_t rev_i = 7 - (i % 8);
        _data[i / 8] += ((vec[_position / 8] & (0x1 << rev_pos)) >> rev_pos) << rev_i;
    }

    return make_cview(_data); // return and increment
}

pipe_in_stream::pipe_in_stream(
    const nlohmann::json &config,
    default_seed_source &seeder,
    std::unordered_map<std::string, std::shared_ptr<std::unique_ptr<stream>>> &pipes,
    const std::size_t osize)
    : stream(0) {
    std::string pipe_id = config.at("id");

    // substream has to be created in advance
    // creating it separately in following if would cause inconsistances
    std::unique_ptr<stream> new_stream = make_stream(config.at("source"), seeder, pipes, osize);

    auto search = pipes.find(pipe_id);
    if (search == pipes.end()) {
        // pipe_id is not yet in hashtable, create new entry
        _source = std::make_shared<std::unique_ptr<stream>>(std::move(new_stream));
        pipes[pipe_id] = _source;
    } else {
        // pipe_id is in hashtable, update the entry for pipe_out
        *pipes[pipe_id] = std::move(new_stream);
        _source = pipes[pipe_id];
    }
}

tuple_stream::tuple_stream(
    const nlohmann::json &config,
    default_seed_source &seeder,
    std::unordered_map<std::string, std::shared_ptr<std::unique_ptr<stream>>> &pipes,
    const std::size_t osize)
    : stream(osize) {
    size_t acc_size = 0;
    for (const auto &stream_cfg : config.at("sources")) {
        const auto cur_osize = std::size_t(stream_cfg.value("output_size", 0));
        acc_size += cur_osize;
        _sources.push_back(make_stream(
            stream_cfg, seeder, pipes, cur_osize));
    }
    if (acc_size > osize) {
        throw std::runtime_error(std::string("Tuple size components are larger than tuple buffer, components: ")
                                 + std::to_string(acc_size) + " vs tuple osize: " + std::to_string(osize));
    }
}

std::unique_ptr<stream>
make_stream(const json &config,
            default_seed_source &seeder,
            std::unordered_map<std::string, std::shared_ptr<std::unique_ptr<stream>>> &pipes,
            const std::size_t osize) {
    const std::string type = config.at("type");

    if (osize == 0 and type != "dummy_stream") { // we allow dummy stream with 0 size
        logger::warning() << "Stream " + type + " have osize 0." << std::endl;
    }

    // trivial source only streams
    if (type == "dummy_stream")
        return std::make_unique<dummy_stream>(osize);
    else if (type == "file_stream")
        return std::make_unique<file_stream>(config, osize);
    else if (type == "true_stream")
        return std::make_unique<true_stream>(osize);
    else if (type == "false_stream")
        return std::make_unique<false_stream>(osize);
    else if (type == "const_stream")
        return std::make_unique<const_stream>(config, osize);
    else if (type == "mt19937_stream")
        return std::make_unique<mt19937_stream>(seeder, osize);
    else if (type == "pcg32_stream" or type == "random_stream")
        return std::make_unique<pcg32_stream>(seeder, osize);

    else if (type == "counter")
        return std::make_unique<counter>(osize);
    else if (type == "random_start_counter")
        return std::make_unique<random_start_counter>(seeder, osize);
    else if (type == "sac")
        return std::make_unique<sac_stream>(seeder, osize);
    else if (type == "sac_fixed_position") {
        const std::size_t pos = std::size_t(config.at("position"));
        return std::make_unique<sac_fixed_pos_stream>(seeder, osize, pos);
    } else if (type == "sac_2d_all_positions")
        return std::make_unique<sac_2d_all_pos>(seeder, osize);
    else if (type == "hw_counter")
        return std::make_unique<hw_counter>(config, seeder, osize);

    // sources with statistical distribution
    else if (type == "bernoulli_distribution")
        return std::make_unique<bernoulli_distribution_stream>(config, seeder, osize);
    else if (type == "binomial_distribution")
        return std::make_unique<binomial_distribution_stream>(config, seeder, osize);
    else if (type == "normal_distribution")
        return std::make_unique<normal_distribution_stream>(config, seeder, osize);
    else if (type == "poisson_distribution")
        return std::make_unique<poisson_distribution_stream>(config, seeder, osize);
    else if (type == "exponential_distribution")
        return std::make_unique<exponential_distribution_stream>(config, seeder, osize);

    // modifiers -- streams that has other stream as an input (but are used as source before cipher)
    else if (type == "single_value_stream")
        return std::make_unique<single_value_stream>(config.at("source"), seeder, pipes, osize);
    else if (type == "repeating_stream")
        return std::make_unique<repeating_stream>(config, seeder, pipes, osize);
    else if (type == "tuple_stream")
        return std::make_unique<tuple_stream>(config, seeder, pipes, osize);

    // pipes
    else if (type == "pipe_in_stream")
        return std::make_unique<pipe_in_stream>(config, seeder, pipes, osize);
    else if (type == "pipe_out_stream")
        return std::make_unique<pipe_out_stream>(config, pipes);

    // postprocessing modifiers -- streams that has cipher stream as an input
    else if (type == "xor_stream")
        return std::make_unique<xor_stream>(config, seeder, pipes, osize);
    else if (type == "column")
        return std::make_unique<column_stream>(config, seeder, pipes, osize);
    else if (type == "column_fixed_position") {
        const std::size_t pos = std::size_t(config.at("position"));
        return std::make_unique<column_fixed_position_stream>(config, seeder, pipes, osize, pos);
    }

    // mock streams for testing
#if (BUILD_testsuite && TEST_STREAM)
    else if (type == "test_stream")
        return std::make_unique<testsuite::test_stream>(config);
#endif

        // cryptoprimitives streams
#ifdef BUILD_stream_ciphers
    else if (type == "stream_cipher" or type == "estream")
        return std::make_unique<stream_ciphers::stream_stream>(config, seeder, pipes, osize);
#endif
#ifdef BUILD_hash
    else if (type == "hash" || type == "sha3")
        return std::make_unique<hash::hash_stream>(config, seeder, pipes, osize);
#endif
#ifdef BUILD_block
    else if (type == "block")
        return std::make_unique<block::block_stream>(config, seeder, pipes, osize);
#endif
#ifdef BUILD_prngs
    else if (type == "prng")
        return std::make_unique<prng::prng_stream>(config, seeder, osize, pipes);
#endif
    throw std::runtime_error("requested stream named \"" + type + "\" does not exist");
}

void stream_to_dataset(dataset &set, std::unique_ptr<stream> &source) {

    auto beg = set.rawdata();
    auto end = set.rawdata() + set.rawsize();

    for (; beg != end;) {
        vec_cview n = source->next();
        beg = std::copy(n.begin(), n.end(), beg);
    }
}