// ----------------------------------------------------------------------------
// -                        Open3D: www.open3d.org                            -
// ----------------------------------------------------------------------------
// The MIT License (MIT)
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// Copyright (c) 2018-2021 www.open3d.org
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#include "open3d/io/PoseGraphIO.h"

#include <unordered_map>

#include "open3d/io/IJsonConvertibleIO.h"
#include "open3d/utility/FileSystem.h"
#include "open3d/utility/Logging.h"

namespace open3d {

namespace {
using namespace io;

bool ReadPoseGraphFromJSON(const std::string &filename,
                           pipelines::registration::PoseGraph &pose_graph) {
    return ReadIJsonConvertible(filename, pose_graph);
}

bool WritePoseGraphToJSON(
        const std::string &filename,
        const pipelines::registration::PoseGraph &pose_graph) {
    return WriteIJsonConvertibleToJSON(filename, pose_graph);
}

static const std::unordered_map<
        std::string,
        std::function<bool(const std::string &,
                           pipelines::registration::PoseGraph &)>>
        file_extension_to_pose_graph_read_function{
                {"json", ReadPoseGraphFromJSON},
        };

static const std::unordered_map<
        std::string,
        std::function<bool(const std::string &,
                           const pipelines::registration::PoseGraph &)>>
        file_extension_to_pose_graph_write_function{
                {"json", WritePoseGraphToJSON},
        };

}  // unnamed namespace

namespace io {
std::shared_ptr<pipelines::registration::PoseGraph> CreatePoseGraphFromFile(
        const std::string &filename) {
    auto pose_graph = std::make_shared<pipelines::registration::PoseGraph>();
    ReadPoseGraph(filename, *pose_graph);
    return pose_graph;
}

bool ReadPoseGraph(const std::string &filename,
                   pipelines::registration::PoseGraph &pose_graph) {
    std::string filename_ext =
            utility::filesystem::GetFileExtensionInLowerCase(filename);
    if (filename_ext.empty()) {
        utility::LogWarning(
                "Read pipelines::registration::PoseGraph failed: unknown file "
                "extension.");
        return false;
    }
    auto map_itr =
            file_extension_to_pose_graph_read_function.find(filename_ext);
    if (map_itr == file_extension_to_pose_graph_read_function.end()) {
        utility::LogWarning(
                "Read pipelines::registration::PoseGraph failed: unknown file "
                "extension.");
        return false;
    }
    return map_itr->second(filename, pose_graph);
}

bool WritePoseGraph(const std::string &filename,
                    const pipelines::registration::PoseGraph &pose_graph) {
    std::string filename_ext =
            utility::filesystem::GetFileExtensionInLowerCase(filename);
    if (filename_ext.empty()) {
        utility::LogWarning(
                "Write pipelines::registration::PoseGraph failed: unknown file "
                "extension.");
        return false;
    }
    auto map_itr =
            file_extension_to_pose_graph_write_function.find(filename_ext);
    if (map_itr == file_extension_to_pose_graph_write_function.end()) {
        utility::LogWarning(
                "Write pipelines::registration::PoseGraph failed: unknown file "
                "extension.");
        return false;
    }
    return map_itr->second(filename, pose_graph);
}

}  // namespace io
}  // namespace open3d
