#include "FilamentGroup.hpp"
#include "GCode/ToolOrderUtils.hpp"
#include "FlushVolPredictor.hpp"
#include <queue>
#include <random>
#include <cassert>
#include <sstream>

namespace Slic3r
{
    using namespace FilamentGroupUtils;
    // clear the array and heap,save the groups in heap to the array
    static void change_memoryed_heaps_to_arrays(MemoryedGroupHeap& heap,const int total_filament_num,const std::vector<unsigned int>& used_filaments, std::vector<std::vector<int>>& arrs)
    {
        // switch the label idx
        arrs.clear();
        while (!heap.empty()) {
            auto top = heap.top();
            heap.pop();
            std::vector<int> labels_tmp(total_filament_num, 0);
            for (size_t idx = 0; idx < top.group.size(); ++idx)
                labels_tmp[used_filaments[idx]] = top.group[idx];
            arrs.emplace_back(std::move(labels_tmp));
        }
    }

    static std::unordered_map<int, int> get_merged_filament_map(const std::unordered_map<int, std::vector<int>>& merged_filaments)
    {
        std::unordered_map<int, int> filament_merge_map;
        for (auto elem : merged_filaments) {
            for (auto f : elem.second) {
                //traverse filaments in merged group
                filament_merge_map[f] = elem.first;
            }
        }
        return filament_merge_map;
    }


    std::vector<int> calc_filament_group_for_tpu(const std::set<int>& tpu_filaments, const int filament_nums, const int master_extruder_id)
    {
        std::vector<int> ret(filament_nums);
        for (size_t fidx = 0; fidx < filament_nums; ++fidx) {
            if (tpu_filaments.count(fidx))
                ret[fidx] = master_extruder_id;
            else
                ret[fidx] = 1 - master_extruder_id;
        }
        return ret;
    }

    bool can_swap_groups(const int extruder_id_0, const std::set<int>& group_0, const int extruder_id_1, const std::set<int>& group_1, const FilamentGroupContext& ctx)
    {
        std::vector<std::set<int>>extruder_unprintables(2);
        {
            std::vector<std::set<int>> unprintable_filaments = ctx.model_info.unprintable_filaments;
            if (unprintable_filaments.size() > 1)
                remove_intersection(unprintable_filaments[0], unprintable_filaments[1]);

            std::map<int, std::vector<int>>unplaceable_limts;
            for (auto& group_id : { extruder_id_0,extruder_id_1 })
                for (auto f : unprintable_filaments[group_id])
                    unplaceable_limts[f].emplace_back(group_id);

            for (auto& elem : unplaceable_limts)
                sort_remove_duplicates(elem.second);

            for (auto& elem : unplaceable_limts) {
                for (auto& eid : elem.second) {
                    if (eid == extruder_id_0) {
                        extruder_unprintables[0].insert(elem.first);
                    }
                    if (eid == extruder_id_1) {
                        extruder_unprintables[1].insert(elem.first);
                    }
                }
            }
        }

        // check printable limits
        for (auto fid : group_0) {
            if (extruder_unprintables[1].count(fid) > 0)
                return false;
        }

        for (auto fid : group_1) {
            if (extruder_unprintables[0].count(fid) > 0)
                return false;
        }

        // check extruder capacity ,if result before exchange meets the constraints and the result after exchange does not meet the constraints, return false
        if (ctx.machine_info.max_group_size[extruder_id_0] >= group_0.size() && ctx.machine_info.max_group_size[extruder_id_1] >= group_1.size() && (ctx.machine_info.max_group_size[extruder_id_0] < group_1.size() || ctx.machine_info.max_group_size[extruder_id_1] < group_0.size()))
            return false;

        return true;
    }


    // only support extruder nums with 2, try to swap the master extruder id with the other extruder id
    std::vector<int> optimize_group_for_master_extruder(const std::vector<unsigned int>& used_filaments,const FilamentGroupContext& ctx, std::vector<int>& filament_map)
    {
        std::vector<int> ret = filament_map;
        std::unordered_map<int, std::set<int>> groups;
        for (size_t idx = 0; idx < used_filaments.size(); ++idx) {
            int filament_id = used_filaments[idx];
            int group_id = ret[filament_id];
            groups[group_id].insert(filament_id);
        }

        int none_master_extruder_id = 1 - ctx.machine_info.master_extruder_id;
        assert(0 <= none_master_extruder_id && none_master_extruder_id <= 1);

        if (can_swap_groups(none_master_extruder_id, groups[none_master_extruder_id], ctx.machine_info.master_extruder_id, groups[ctx.machine_info.master_extruder_id], ctx)
            && groups[none_master_extruder_id].size()>groups[ctx.machine_info.master_extruder_id].size()) {
            for (auto fid : groups[none_master_extruder_id])
                ret[fid] = ctx.machine_info.master_extruder_id;
            for (auto fid : groups[ctx.machine_info.master_extruder_id])
                ret[fid] = none_master_extruder_id;
        }
        return ret;
    }

    /**
     * @brief Select the group that best fit the filaments in AMS
     *
     * Calculate the total color distance between the grouping results and the AMS filaments through
     * minimum cost maximum flow. Only those with a distance difference within the threshold are
     * considered valid.
     *
     * @param map_lists Group list with similar flush count
     * @param used_filaments Idx of used filaments
     * @param used_filament_info Information of filaments used
     * @param machine_filament_info Information of filaments loaded in printer
     * @param color_threshold Threshold for considering colors to be similar
     * @return The group that best fits the filament distribution in AMS
     */
    std::vector<int> select_best_group_for_ams(const std::vector<std::vector<int>>& map_lists,
        const std::vector<unsigned int>& used_filaments,
        const std::vector<FilamentInfo>& used_filament_info,
        const std::vector<std::vector<MachineFilamentInfo>>& machine_filament_info_,
        const double color_threshold)
    {
        using namespace FlushPredict;

        const int fail_cost = 9999;

        // these code is to make we machine filament info size is 2
        std::vector<std::vector<MachineFilamentInfo>> machine_filament_info = machine_filament_info_;
        machine_filament_info.resize(2);

        int best_cost = std::numeric_limits<int>::max();
        std::vector<int>best_map;

        for (auto& map : map_lists) {
            std::vector<std::vector<int>> group_filaments(2);
            std::vector<std::vector<Color>>group_colors(2);

            for (size_t i = 0; i < used_filaments.size(); ++i) {
                int target_group = map[used_filaments[i]] == 0 ? 0 : 1;
                group_colors[target_group].emplace_back(used_filament_info[i].color);
                group_filaments[target_group].emplace_back(i);
            }

            int group_cost = 0;
            for (size_t i = 0; i < 2; ++i) {
                if (group_colors[i].empty())
                    continue;
                if (machine_filament_info[i].empty()) {
                    group_cost += group_colors.size() * fail_cost;
                    continue;
                }
                std::vector<std::vector<float>>distance_matrix(group_colors[i].size(), std::vector<float>(machine_filament_info[i].size()));

                // calculate color distance matrix
                for (size_t src = 0; src < group_colors[i].size(); ++src) {
                    for (size_t dst = 0; dst < machine_filament_info[i].size(); ++dst) {
                        distance_matrix[src][dst] = calc_color_distance(
                            RGBColor(group_colors[i][src].r, group_colors[i][src].g, group_colors[i][src].b),
                            RGBColor(machine_filament_info[i][dst].color.r, machine_filament_info[i][dst].color.g, machine_filament_info[i][dst].color.b)
                        );
                    }
                }

                // get min cost by min cost max flow
                std::vector<int>l_nodes(group_colors[i].size()), r_nodes(machine_filament_info[i].size());
                std::iota(l_nodes.begin(), l_nodes.end(), 0);
                std::iota(r_nodes.begin(), r_nodes.end(), 0);

                std::unordered_map<int, std::vector<int>>unlink_limits;
                for (size_t from = 0; from < group_filaments[i].size(); ++from) {
                    for (size_t to = 0; to < machine_filament_info[i].size(); ++to) {
                        if (used_filament_info[group_filaments[i][from]].type != machine_filament_info[i][to].type ||
                            used_filament_info[group_filaments[i][from]].is_support != machine_filament_info[i][to].is_support) {
                            unlink_limits[from].emplace_back(to);
                        }
                    }
                }

                MatchModeGroupSolver mcmf(distance_matrix, l_nodes, r_nodes, std::vector<int>(r_nodes.size(), l_nodes.size()), unlink_limits);
                auto ams_map = mcmf.solve();

                for (size_t idx = 0; idx < ams_map.size(); ++idx) {
                    if (ams_map[idx] == MaxFlowGraph::INVALID_ID || distance_matrix[idx][ams_map[idx]] > color_threshold) {
                        group_cost += fail_cost;
                    }
                    else {
                        group_cost += distance_matrix[idx][ams_map[idx]];
                    }
                }
            }

            if (best_map.empty() || group_cost < best_cost) {
                best_cost = group_cost;
                best_map = map;
            }
        }

        return best_map;
    }


    void FilamentGroupUtils::update_memoryed_groups(const MemoryedGroup& item, const double gap_threshold, MemoryedGroupHeap& groups)
    {
        auto emplace_if_accepatle = [gap_threshold](MemoryedGroupHeap& heap, const MemoryedGroup& elem, const MemoryedGroup& best) {
            if (best.cost == 0) {
                if (std::abs(elem.cost - best.cost) <= ABSOLUTE_FLUSH_GAP_TOLERANCE)
                    heap.push(elem);
                return;
            }
            double gap_rate = (double)std::abs(elem.cost - best.cost) / (double)best.cost;
            if (gap_rate < gap_threshold)
                heap.push(elem);
            };

        if (groups.empty()) {
            groups.push(item);
        }
        else {
            auto top = groups.top();
            // we only memory items with the highest prefer level
            if (top.prefer_level > item.prefer_level)
                return;
            else if (top.prefer_level == item.prefer_level) {
                if (top.cost <= item.cost) {
                    emplace_if_accepatle(groups, item, top);
                }
                // find a group with lower cost, rebuild the heap
                else {
                    MemoryedGroupHeap new_heap;
                    new_heap.push(item);
                    while (!groups.empty()) {
                        auto top = groups.top();
                        groups.pop();
                        emplace_if_accepatle(new_heap, top, item);
                    }
                    groups = std::move(new_heap);
                }
            }
            // find a group with the higher prefer level, rebuild the heap
            else {
                groups = MemoryedGroupHeap();
                groups.push(item);
            }
        }
    }

    std::vector<unsigned int> collect_sorted_used_filaments(const std::vector<std::vector<unsigned int>>& layer_filaments)
    {
        std::set<unsigned int>used_filaments_set;
        for (const auto& lf : layer_filaments)
            for (const auto& f : lf)
                used_filaments_set.insert(f);
        std::vector<unsigned int>used_filaments(used_filaments_set.begin(), used_filaments_set.end());
        std::sort(used_filaments.begin(), used_filaments.end());
        return used_filaments;
    }

    FlushDistanceEvaluator::FlushDistanceEvaluator(const FlushMatrix& flush_matrix, const std::vector<unsigned int>& used_filaments, const std::vector<std::vector<unsigned int>>& layer_filaments, double p)
    {
        //calc pair counts
        std::vector<std::vector<int>>count_matrix(used_filaments.size(), std::vector<int>(used_filaments.size()));
        for (const auto& lf : layer_filaments) {
            for (auto iter = lf.begin(); iter != lf.end(); ++iter) {
                auto id_iter1 = std::find(used_filaments.begin(), used_filaments.end(), *iter);
                if (id_iter1 == used_filaments.end())
                    continue;
                auto idx1 = id_iter1 - used_filaments.begin();
                for (auto niter = std::next(iter); niter != lf.end(); ++niter) {
                    auto id_iter2 = std::find(used_filaments.begin(), used_filaments.end(), *niter);
                    if (id_iter2 == used_filaments.end())
                        continue;
                    auto idx2 = id_iter2 - used_filaments.begin();
                    count_matrix[idx1][idx2] += 1;
                    count_matrix[idx2][idx1] += 1;
                }
            }
        }

        m_distance_matrix.resize(used_filaments.size(), std::vector<float>(used_filaments.size()));

        for (size_t i = 0; i < used_filaments.size(); ++i) {
            for (size_t j = 0; j < used_filaments.size(); ++j) {
                if (i == j)
                    m_distance_matrix[i][j] = 0;
                else {
                    //TODO: check m_flush_matrix
                    float max_val = std::max(flush_matrix[used_filaments[i]][used_filaments[j]], flush_matrix[used_filaments[j]][used_filaments[i]]);
                    float min_val = std::min(flush_matrix[used_filaments[i]][used_filaments[j]], flush_matrix[used_filaments[j]][used_filaments[i]]);
                    m_distance_matrix[i][j] = (max_val * p + min_val * (1 - p)) * count_matrix[i][j];
                }
            }
        }
    }

    double FlushDistanceEvaluator::get_distance(int idx_a, int idx_b) const
    {
        assert(0 <= idx_a && idx_a < m_distance_matrix.size());
        assert(0 <= idx_b && idx_b < m_distance_matrix.size());

        return m_distance_matrix[idx_a][idx_b];
    }

    std::vector<int> KMediods2::cluster_small_data(const std::map<int, int>& unplaceable_limits, const std::vector<int>& group_size)
    {
        std::vector<int>labels(m_elem_count, -1);
        std::vector<int>new_group_size = group_size;

        for (auto& [elem, center] : unplaceable_limits) {
            if (labels[elem] == -1) {
                int gid = 1 - center;
                labels[elem] = gid;
                new_group_size[gid] -= 1;
            }
        }

        for (auto& label : labels) {
            if (label == -1) {
                int gid = -1;
                for (size_t idx = 0; idx < new_group_size.size(); ++idx) {
                    if (new_group_size[idx] > 0) {
                        gid = idx;
                        break;
                    }
                }
                if (gid != -1) {
                    label = gid;
                    new_group_size[gid] -= 1;
                }
                else {
                    label = m_default_group_id;
                }
            }
        }

        return labels;
    }

    std::vector<int> KMediods2::assign_cluster_label(const std::vector<int>& center, const std::map<int, int>& unplaceable_limtis, const std::vector<int>& group_size, const FGStrategy& strategy)
    {
        struct Comp {
            bool operator()(const std::pair<int, int>& a, const std::pair<int, int>& b) {
                return a.second > b.second;
            }
        };

        std::vector<std::set<int>>groups(2);
        std::vector<int>new_max_group_size = group_size;
        // store filament idx and distance gap between center 0 and center 1
        std::priority_queue<std::pair<int, int>, std::vector<std::pair<int, int>>, Comp>min_heap;

        for (int i = 0; i < m_elem_count; ++i) {
            if (auto it = unplaceable_limtis.find(i); it != unplaceable_limtis.end()) {
                int gid = it->second;
                assert(gid == 0 || gid == 1);
                groups[1 - gid].insert(i);   // insert to group
                new_max_group_size[1 - gid] = std::max(new_max_group_size[1 - gid] - 1, 0); // decrease group_size
                continue;
            }
            int distance_to_0 = m_evaluator->get_distance(i, center[0]);
            int distance_to_1 = m_evaluator->get_distance(i, center[1]);
            min_heap.push({ i,distance_to_0 - distance_to_1 });
        }

        bool have_enough_size = (min_heap.size() <= (new_max_group_size[0] + new_max_group_size[1]));

        if (have_enough_size || strategy == FGStrategy::BestFit) {
            while (!min_heap.empty()) {
                auto top = min_heap.top();
                min_heap.pop();
                if (groups[0].size() < new_max_group_size[0] && (top.second <= 0 || groups[1].size() >= new_max_group_size[1]))
                    groups[0].insert(top.first);
                else if (groups[1].size() < new_max_group_size[1] && (top.second > 0 || groups[0].size() >= new_max_group_size[0]))
                    groups[1].insert(top.first);
                else {
                    if (top.second <= 0)
                        groups[0].insert(top.first);
                    else
                        groups[1].insert(top.first);
                }
            }
        }
        else {
            while (!min_heap.empty()) {
                auto top = min_heap.top();
                min_heap.pop();
                if (top.second <= 0)
                    groups[0].insert(top.first);
                else
                    groups[1].insert(top.first);
            }
        }

        std::vector<int>labels(m_elem_count);
        for (auto& f : groups[0])
            labels[f] = 0;
        for (auto& f : groups[1])
            labels[f] = 1;

        return labels;
    }

    int KMediods2::calc_cost(const std::vector<int>& labels, const std::vector<int>& medoids)
    {
        int total_cost = 0;
        for (int i = 0; i < m_elem_count; ++i)
            total_cost += m_evaluator->get_distance(i, medoids[labels[i]]);
        return total_cost;
    }

    void KMediods2::do_clustering(const FGStrategy& g_strategy, int timeout_ms)
    {
        FlushTimeMachine T;
        T.time_machine_start();

        if (m_elem_count < m_k) {
            m_cluster_labels = cluster_small_data(m_unplaceable_limits, m_max_cluster_size);
            {
                std::vector<int>cluster_center(m_k, -1);
                for (size_t idx = 0; idx < m_cluster_labels.size(); ++idx) {
                    if (cluster_center[m_cluster_labels[idx]] == -1)
                        cluster_center[m_cluster_labels[idx]] = idx;
                }
                MemoryedGroup g(m_cluster_labels, calc_cost(m_cluster_labels, cluster_center), 1);
                update_memoryed_groups(g, memory_threshold, memoryed_groups);
            }
            return;
        }

        std::vector<int>best_labels;
        int best_cost = std::numeric_limits<int>::max();

        for (int center_0 = 0; center_0 < m_elem_count; ++center_0) {
            if (auto iter = m_unplaceable_limits.find(center_0); iter != m_unplaceable_limits.end() && iter->second == 0)
                continue;
            for (int center_1 = 0; center_1 < m_elem_count; ++center_1) {
                if (center_0 == center_1)
                    continue;
                if (auto iter = m_unplaceable_limits.find(center_1); iter != m_unplaceable_limits.end() && iter->second == 1)
                    continue;

                std::vector<int>new_centers = { center_0,center_1 };
                std::vector<int>new_labels = assign_cluster_label(new_centers, m_unplaceable_limits, m_max_cluster_size, g_strategy);

                int new_cost = calc_cost(new_labels, new_centers);
                if (new_cost < best_cost) {
                    best_cost = new_cost;
                    best_labels = new_labels;
                }

                {
                    MemoryedGroup g(new_labels,new_cost,1);
                    update_memoryed_groups(g, memory_threshold, memoryed_groups);
                }

                if (T.time_machine_end() > timeout_ms)
                    break;
            }
            if (T.time_machine_end() > timeout_ms)
                break;
        }
        this->m_cluster_labels = best_labels;
    }

    std::vector<int> FilamentGroup::calc_min_flush_group(int* cost)
    {
        auto used_filaments = collect_sorted_used_filaments(ctx.model_info.layer_filaments);
        int used_filament_num = used_filaments.size();

        if (used_filament_num < 10)
            return calc_min_flush_group_by_enum(used_filaments, cost);
        else
            return calc_min_flush_group_by_pam2(used_filaments, cost, 500);
    }

    std::unordered_map<int, std::vector<int>> FilamentGroup::try_merge_filaments()
    {
        std::unordered_map<int, std::vector<int>>merged_filaments;

        std::unordered_map<std::string, std::vector<int>> merge_filament_map;

        auto unprintable_stat_to_str = [unprintable_filaments = this->ctx.model_info.unprintable_filaments](int idx) {
            std::string str;
            for (size_t eid = 0; eid < unprintable_filaments.size(); ++eid) {
                if (unprintable_filaments[eid].count(idx)) {
                    if (eid > 0)
                        str += ',';
                    str += std::to_string(idx);
                }
            }
            return str;
            };

        for (size_t idx = 0; idx < ctx.model_info.filament_ids.size(); ++idx) {
            std::string id = ctx.model_info.filament_ids[idx];
            Color color = ctx.model_info.filament_info[idx].color;
            std::string unprintable_str = unprintable_stat_to_str(idx);

            std::string key = id + "," + color.to_hex_str(true) + "," + unprintable_str;
            merge_filament_map[key].push_back(idx);
        }

        for (auto& elem : merge_filament_map) {
            if (elem.second.size() > 1) {
                merged_filaments[elem.second.front()] = elem.second;
            }
        }
        return merged_filaments;
    }

    std::vector<int> FilamentGroup::seperate_merged_filaments(const std::vector<int>& filament_map, const std::unordered_map<int, std::vector<int>>& merged_filaments)
    {
        std::vector<int> ret_map = filament_map;
        for (auto& elem : merged_filaments) {
            int src = elem.first;
            for (auto f : elem.second) {
                ret_map[f] = ret_map[src];
            }
        }
        return ret_map;
    }

    void  FilamentGroup::rebuild_context(const std::unordered_map<int, std::vector<int>>& merged_filaments)
    {
        if (merged_filaments.empty())
            return;

        FilamentGroupContext new_ctx = ctx;

        std::unordered_map<int, int> filament_merge_map = get_merged_filament_map(merged_filaments);

        // modify layer filaments
        for (auto& layer_filament : new_ctx.model_info.layer_filaments) {
            for (auto& f : layer_filament) {
                if (auto iter = filament_merge_map.find((int)(f)); iter != filament_merge_map.end()) {
                    f = iter->second;
                }
            }
        }

        for (auto& unprintables : new_ctx.model_info.unprintable_filaments) {
            std::set<int> new_unprintables;
            for (auto f : unprintables) {
                if (auto iter = filament_merge_map.find((int)(f)); iter != filament_merge_map.end()) {
                    new_unprintables.insert(iter->second);
                }
                else {
                    new_unprintables.insert(f);
                }
            }
        }

        ctx = new_ctx;
        return;
    }



    std::vector<int> FilamentGroup::calc_filament_group(int* cost)
    {
        try {
            if (FGMode::MatchMode == ctx.group_info.mode)
                return calc_filament_group_for_match(cost);
        }
        catch (const FilamentGroupException& e) {
        }

        auto merged_map = try_merge_filaments();
        rebuild_context(merged_map);
        auto filamnet_map = calc_filament_group_for_flush(cost);
        return seperate_merged_filaments(filamnet_map, merged_map);
    }

    std::vector<int> FilamentGroup::calc_filament_group_for_match(int* cost)
    {
        using namespace FlushPredict;

        auto used_filaments = collect_sorted_used_filaments(ctx.model_info.layer_filaments);
        std::vector<FilamentInfo> used_filament_list;
        for (auto f : used_filaments)
            used_filament_list.emplace_back(ctx.model_info.filament_info[f]);

        std::vector<MachineFilamentInfo> machine_filament_list;
        std::map<MachineFilamentInfo, std::set<int>> machine_filament_set;
        for (size_t eid = 0; eid < ctx.machine_info.machine_filament_info.size();++eid) {
            for (auto& filament : ctx.machine_info.machine_filament_info[eid]) {
                machine_filament_set[filament].insert(machine_filament_list.size());
                machine_filament_list.emplace_back(filament);
            }
        }

        if (machine_filament_list.empty())
            throw FilamentGroupException(FilamentGroupException::EmptyAmsFilaments,"Empty ams filament in For-Match mode.");

        std::map<int, int> unprintable_limit_indices; // key stores filament idx in used_filament, value stores unprintable extruder
        extract_unprintable_limit_indices(ctx.model_info.unprintable_filaments, used_filaments, unprintable_limit_indices);

        std::vector<std::vector<float>> color_dist_matrix(used_filament_list.size(), std::vector<float>(machine_filament_list.size()));
        for (size_t i = 0; i < used_filament_list.size(); ++i) {
            for (size_t j = 0; j < machine_filament_list.size(); ++j) {
                color_dist_matrix[i][j] = calc_color_distance(
                    RGBColor(used_filament_list[i].color.r, used_filament_list[i].color.g, used_filament_list[i].color.b),
                    RGBColor(machine_filament_list[j].color.r, machine_filament_list[j].color.g, machine_filament_list[j].color.b)
                );
            }
        }

        std::vector<int>l_nodes(used_filaments.size());
        std::iota(l_nodes.begin(), l_nodes.end(), 0);
        std::vector<int>r_nodes(machine_filament_list.size());
        std::iota(r_nodes.begin(), r_nodes.end(), 0);
        std::vector<int>machine_filament_capacity(machine_filament_list.size(),l_nodes.size());
        std::vector<int>extruder_filament_count(2, 0);

        auto is_extruder_filament_compatible = [&unprintable_limit_indices](int filament_idx, int extruder_id) {
            auto iter = unprintable_limit_indices.find(filament_idx);
            if (iter != unprintable_limit_indices.end() && iter->second == extruder_id)
                return false;
            return true;
            };

        auto build_unlink_limits = [](const std::vector<int>& l_nodes, const std::vector<int>& r_nodes, const std::function<bool(int, int)>& can_link) {
            std::unordered_map<int, std::vector<int>> unlink_limits;
            for (size_t i = 0; i < l_nodes.size(); ++i) {
                std::vector<int> unlink_filaments;
                for (size_t j = 0; j < r_nodes.size(); ++j) {
                    if (!can_link(l_nodes[i], r_nodes[j]))
                        unlink_filaments.emplace_back(j);
                }
                if (!unlink_filaments.empty())
                    unlink_limits.emplace(i, std::move(unlink_filaments));
            }
            return unlink_limits;
            };

        auto optimize_map_to_machine_filament = [&](const std::vector<int>& map_to_machine_filament, const std::vector<int>& l_nodes, const std::vector<int>& r_nodes, std::vector<int>& filament_map, bool consider_capacity) {
            std::vector<int> ungrouped_filaments;
            std::vector<int> filaments_to_optimize;

            auto map_filament_to_machine_filament = [&](int filament_idx, int machine_filament_idx) {
                auto& machine_filament = machine_filament_list[machine_filament_idx];
                machine_filament_capacity[machine_filament_idx] = std::max(0, machine_filament_capacity[machine_filament_idx] - 1);  // decrease machine filament capacity
                filament_map[used_filaments[filament_idx]] = machine_filament.extruder_id;  // set extruder id to filament map
                extruder_filament_count[machine_filament.extruder_id] += 1; // increase filament count in extruder
                };
            auto unmap_filament_to_machine_filament = [&](int filament_idx, int machine_filament_idx) {
                auto& machine_filament = machine_filament_list[machine_filament_idx];
                machine_filament_capacity[machine_filament_idx] += 1;  // increase machine filament capacity
                extruder_filament_count[machine_filament.extruder_id] -= 1; // increase filament count in extruder
                };

            for (size_t idx = 0; idx < map_to_machine_filament.size(); ++idx) {
                if (map_to_machine_filament[idx] == MaxFlowGraph::INVALID_ID) {
                    ungrouped_filaments.emplace_back(l_nodes[idx]);
                    continue;
                }
                int used_filament_idx = l_nodes[idx];
                int machine_filament_idx = r_nodes[map_to_machine_filament[idx]];
                auto& machine_filament = machine_filament_list[machine_filament_idx];
                if (machine_filament_set[machine_filament].size() > 1 && unprintable_limit_indices.count(used_filament_idx) == 0)
                    filaments_to_optimize.emplace_back(idx);

                map_filament_to_machine_filament(used_filament_idx, machine_filament_idx);
            }
            // try to optimize the result
            for (auto idx : filaments_to_optimize) {
                int filament_idx = l_nodes[idx];
                int old_machine_filament_idx = r_nodes[map_to_machine_filament[idx]];
                auto& old_machine_filament = machine_filament_list[old_machine_filament_idx];

                int curr_gap = std::abs(extruder_filament_count[0] - extruder_filament_count[1]);
                unmap_filament_to_machine_filament(filament_idx, old_machine_filament_idx);

                auto optional_filaments = machine_filament_set[old_machine_filament];
                auto iter = optional_filaments.begin();
                for (; iter != optional_filaments.end(); ++iter) {
                    int new_extruder_id = machine_filament_list[*iter].extruder_id;
                    int new_gap = std::abs(extruder_filament_count[new_extruder_id] + 1 - extruder_filament_count[1 - new_extruder_id]);
                    if (new_gap < curr_gap && (!consider_capacity || machine_filament_capacity[*iter] > 0)) {
                        map_filament_to_machine_filament(filament_idx, *iter);
                        break;
                    }
                }

                if (iter == optional_filaments.end())
                    map_filament_to_machine_filament(filament_idx, old_machine_filament_idx);
            }
            return ungrouped_filaments;
            };

        std::vector<int> group(ctx.group_info.total_filament_num, ctx.machine_info.master_extruder_id);
        std::vector<int> ungrouped_filaments;

        auto unlink_limits_full = build_unlink_limits(l_nodes, r_nodes, [&used_filament_list, &machine_filament_list, is_extruder_filament_compatible](int used_filament_idx, int machine_filament_idx) {
            return used_filament_list[used_filament_idx].type == machine_filament_list[machine_filament_idx].type &&
                used_filament_list[used_filament_idx].is_support == machine_filament_list[machine_filament_idx].is_support &&
                is_extruder_filament_compatible(used_filament_idx, machine_filament_list[machine_filament_idx].extruder_id);
            });

        {
            MatchModeGroupSolver s(color_dist_matrix, l_nodes, r_nodes, machine_filament_capacity, unlink_limits_full);
            ungrouped_filaments = optimize_map_to_machine_filament(s.solve(), l_nodes, r_nodes,group,false);
            if (ungrouped_filaments.empty())
                return group;
        }

        // additionally remove type limits
        {
            l_nodes = ungrouped_filaments;
            auto unlink_limits = build_unlink_limits(l_nodes, r_nodes, [&machine_filament_list, is_extruder_filament_compatible](int used_filament_idx, int machine_filament_idx) {
                return is_extruder_filament_compatible(used_filament_idx, machine_filament_list[machine_filament_idx].extruder_id);
                });

            MatchModeGroupSolver s(color_dist_matrix, l_nodes, r_nodes, machine_filament_capacity, unlink_limits);
            ungrouped_filaments = optimize_map_to_machine_filament(s.solve(), l_nodes, r_nodes, group,false);
            if (ungrouped_filaments.empty())
                return group;
        }

        // remove all limits
        {
            l_nodes = ungrouped_filaments;
            MatchModeGroupSolver s(color_dist_matrix, l_nodes, r_nodes, machine_filament_capacity, {});
            auto ret = optimize_map_to_machine_filament(s.solve(), l_nodes, r_nodes, group,false);
            for (size_t idx = 0; idx < ret.size(); ++idx) {
                if (ret[idx] == MaxFlowGraph::INVALID_ID)
                    assert(false);
                else
                    group[used_filaments[l_nodes[idx]]] = machine_filament_list[r_nodes[ret[idx]]].extruder_id;
            }
        }

        return group;
    }

    std::vector<int> FilamentGroup::calc_filament_group_for_flush(int* cost)
    {
        auto used_filaments = collect_sorted_used_filaments(ctx.model_info.layer_filaments);

        std::vector<int> ret = calc_min_flush_group(cost);
        std::vector<std::vector<int>> memoryed_maps = this->m_memoryed_groups;
        memoryed_maps.insert(memoryed_maps.begin(), ret);

        std::vector<int> optimized_ret = optimize_group_for_master_extruder(used_filaments, ctx, ret);
        if (optimized_ret != ret)
            memoryed_maps.insert(memoryed_maps.begin(), optimized_ret);

        std::vector<FilamentGroupUtils::FilamentInfo> used_filament_info;
        for (auto f : used_filaments) {
            used_filament_info.emplace_back(ctx.model_info.filament_info[f]);
        }

        ret = select_best_group_for_ams(memoryed_maps, used_filaments, used_filament_info, ctx.machine_info.machine_filament_info);
        return ret;
    }


    // sorted used_filaments
    std::vector<int> FilamentGroup::calc_min_flush_group_by_enum(const std::vector<unsigned int>& used_filaments, int* cost)
    {
        static constexpr int UNPLACEABLE_LIMIT_REWARD = 100;  // reward value if the group result follows the unprintable limit
        static constexpr int MAX_SIZE_LIMIT_REWARD = 10;    // reward value if the group result follows the max size per extruder
        static constexpr int BEST_FIT_LIMIT_REWARD = 1;     // reward value if the group result try to fill the max size per extruder

        MemoryedGroupHeap memoryed_groups;

        auto bit_count_one = [](uint64_t n)
            {
                int count = 0;
                while (n != 0)
                {
                    n &= n - 1;
                    count++;
                }
                return count;
            };

        std::map<int, int>unplaceable_limit_indices;
        extract_unprintable_limit_indices(ctx.model_info.unprintable_filaments, used_filaments, unplaceable_limit_indices);

        int used_filament_num = used_filaments.size();
        uint64_t max_group_num = (static_cast<uint64_t>(1) << used_filament_num);

        int best_cost = std::numeric_limits<int>::max();
        std::vector<int>best_label;
        int best_prefer_level = 0;

        for (uint64_t i = 0; i < max_group_num; ++i) {
            std::vector<std::set<int>>groups(2);
            for (int j = 0; j < used_filament_num; ++j) {
                if (i & (static_cast<uint64_t>(1) << j))
                    groups[1].insert(j);
                else
                    groups[0].insert(j);
            }

            int prefer_level = 0;

            if (check_printable(groups, unplaceable_limit_indices))
                prefer_level += UNPLACEABLE_LIMIT_REWARD;
            if (groups[0].size() <= ctx.machine_info.max_group_size[0] && groups[1].size() <= ctx.machine_info.max_group_size[1])
                prefer_level += MAX_SIZE_LIMIT_REWARD;
            if (FGStrategy::BestFit == ctx.group_info.strategy && groups[0].size() >= ctx.machine_info.max_group_size[0] && groups[1].size() >= ctx.machine_info.max_group_size[1])
                prefer_level += BEST_FIT_LIMIT_REWARD;

            std::vector<int>filament_maps(used_filament_num);
            for (int i = 0; i < used_filament_num; ++i) {
                if (groups[0].find(i) != groups[0].end())
                    filament_maps[i] = 0;
                if (groups[1].find(i) != groups[1].end())
                    filament_maps[i] = 1;
            }

            int total_cost = reorder_filaments_for_minimum_flush_volume(
                used_filaments,
                filament_maps,
                ctx.model_info.layer_filaments,
                ctx.model_info.flush_matrix,
                get_custom_seq,
                nullptr
            );

            if (prefer_level > best_prefer_level || (prefer_level == best_prefer_level && total_cost < best_cost)) {
                best_prefer_level = prefer_level;
                best_cost = total_cost;
                best_label = filament_maps;
            }

            {
                MemoryedGroup mg(filament_maps, total_cost, prefer_level);
                update_memoryed_groups(mg, ctx.group_info.max_gap_threshold, memoryed_groups);
            }
        }

        if (cost)
            *cost = best_cost;

        std::vector<int> filament_labels(ctx.group_info.total_filament_num, 0);
        for (size_t i = 0; i < best_label.size(); ++i)
            filament_labels[used_filaments[i]] = best_label[i];


        change_memoryed_heaps_to_arrays(memoryed_groups, ctx.group_info.total_filament_num, used_filaments, m_memoryed_groups);

        return filament_labels;
    }

    // sorted used_filaments
    std::vector<int> FilamentGroup::calc_min_flush_group_by_pam2(const std::vector<unsigned int>& used_filaments, int* cost, int timeout_ms)
    {
        std::vector<int>filament_labels_ret(ctx.group_info.total_filament_num, ctx.machine_info.master_extruder_id);

        std::map<int, int>unplaceable_limits;
        extract_unprintable_limit_indices(ctx.model_info.unprintable_filaments, used_filaments, unplaceable_limits);

        auto distance_evaluator = std::make_shared<FlushDistanceEvaluator>(ctx.model_info.flush_matrix[0], used_filaments, ctx.model_info.layer_filaments);
        KMediods2 PAM((int)used_filaments.size(), distance_evaluator, ctx.machine_info.master_extruder_id);
        PAM.set_max_cluster_size(ctx.machine_info.max_group_size);
        PAM.set_unplaceable_limits(unplaceable_limits);
        PAM.set_memory_threshold(ctx.group_info.max_gap_threshold);
        PAM.do_clustering(ctx.group_info.strategy, timeout_ms);

        std::vector<int>filament_labels = PAM.get_cluster_labels();

        {
            auto memoryed_groups = PAM.get_memoryed_groups();
            change_memoryed_heaps_to_arrays(memoryed_groups, ctx.group_info.total_filament_num, used_filaments, m_memoryed_groups);
        }

        if (cost)
            *cost = reorder_filaments_for_minimum_flush_volume(used_filaments, filament_labels, ctx.model_info.layer_filaments, ctx.model_info.flush_matrix, std::nullopt, nullptr);

        for (int i = 0; i < filament_labels.size(); ++i)
            filament_labels_ret[used_filaments[i]] = filament_labels[i];
        return filament_labels_ret;
    }

}