#include "mesh_decoder.h"
#include "mesh_codec.hpp"
#include "third_party/static_block.hpp"
#include "impl/main_impl.h"

#include <unordered_map>

using namespace mesh_codec;

namespace mesh_decoder_impl {

    using mesh_map_type =
            std::unordered_map<size_t, mesh_ptr>;
    mesh_map_type mesh_pool;

    static_block {
        register_cleanup_func([] { mesh_pool.clear(); });
    }

    using hasher_type = std::hash<std::string>;
    hasher_type name_hasher;

    mesh_ptr get_no_transfer_mesh(size_t name) {
        assert(mesh_pool.contains(name));
        return mesh_pool.at(name);
    }

}

using namespace mesh_decoder_impl;

struct mesh_decoder::impl {

    using cache_map_type =
            std::unordered_map<hash_type, mesh_ptr>;
    cache_map_type cache_map;

    static mesh_ptr decode_mesh(const data_type &data) {
        auto ret = mesh_type::raw_info_type();
        auto reader = network_reader(data);
        reader >> ret.num_triangles;
        auto vbo_size = reader.read_value<size_t>();
        ret.vbo_data = reader.read_data(vbo_size);
        auto ebo_size = reader.read_value<size_t>();
        ret.ebo_data = reader.read_data(ebo_size);
        assert(reader.empty());
        return mesh_type::from_raw(ret);
    }

    mesh_ptr decode(const data_type &data) {
        auto reader = network_reader(data);
        auto flag = reader.read_value<flag_type>();

        if (flag == FLAG_NO_TRANSFER) {
            auto name = reader.read_value<size_t>();
            return get_no_transfer_mesh(name);
        }

        auto id = reader.read_value<hash_type>();
        if (cache_map.contains(id)) {
            return cache_map.at(id);
        }

//        assert(!reader.empty());
        if (reader.empty()) return nullptr; // TODO: mesh IDR may not be handled???
        auto mesh = decode_mesh(reader.read_remain());
        if (flag != FLAG_NO_CACHE) {
            assert(!cache_map.contains(id));
            cache_map.emplace(id, mesh);
        }

        return mesh;
    }

};

mesh_decoder::mesh_decoder(create_config _)
        : pimpl(std::make_unique<impl>()) {
}

mesh_decoder::~mesh_decoder() = default;

mesh_ptr mesh_decoder::decode(const data_type &data) {
    return pimpl->decode(data);
}

void register_mesh_file(const std::string &name,
                        const std::string &path) {
    auto mesh = mesh_type::create({.path = path});
    auto name_id = name_hasher(name);
    assert(!mesh_pool.contains(name_id));
    mesh_pool.emplace(name_id, mesh);
}

void register_mesh_list(const YAML::Node &conf_list) {
    for (auto &conf: conf_list) {
        register_mesh_file(LOAD_STR("name"), LOAD_STR("path"));
    }
}