// ----------------------------------------------------------------------------
// -                        Open3D: www.open3d.org                            -
// ----------------------------------------------------------------------------
// Copyright (c) 2018-2023 www.open3d.org
// SPDX-License-Identifier: MIT
// ----------------------------------------------------------------------------

#include <liblzf/lzf.h>

#include <cinttypes>
#include <cstdint>
#include <cstdio>
#include <sstream>

#include "open3d/core/Dtype.h"
#include "open3d/core/ParallelFor.h"
#include "open3d/core/Tensor.h"
#include "open3d/io/FileFormatIO.h"
#include "open3d/t/io/PointCloudIO.h"
#include "open3d/utility/FileSystem.h"
#include "open3d/utility/Helper.h"
#include "open3d/utility/Logging.h"
#include "open3d/utility/ProgressReporters.h"

// References for PCD file IO
// http://pointclouds.org/documentation/tutorials/pcd_file_format.html
// https://github.com/PointCloudLibrary/pcl/blob/master/io/src/pcd_io.cpp
// https://www.mathworks.com/matlabcentral/fileexchange/40382-matlab-to-point-cloud-library

namespace open3d {
namespace t {
namespace io {

enum class PCDDataType { ASCII = 0, BINARY = 1, BINARY_COMPRESSED = 2 };

struct PCLPointField {
public:
    std::string name;
    int size;
    char type;
    int count;
    // helper variable
    int count_offset = 0;
    int offset = 0;
};

struct PCDHeader {
public:
    std::string version;
    std::vector<PCLPointField> fields;
    int width;
    int height;
    int points;
    PCDDataType datatype;
    std::string viewpoint;

    // helper variables
    int elementnum;
    int pointsize;
    std::unordered_map<std::string, bool> has_attr;
    std::unordered_map<std::string, core::Dtype> attr_dtype;
};

struct ReadAttributePtr {
    ReadAttributePtr(void *data_ptr = nullptr,
                     const int row_idx = 0,
                     const int row_length = 0,
                     const int size = 0)
        : data_ptr_(data_ptr),
          row_idx_(row_idx),
          row_length_(row_length),
          size_(size) {}

    void *data_ptr_;
    const int row_idx_;
    const int row_length_;
    const int size_;
};

struct WriteAttributePtr {
    WriteAttributePtr(const core::Dtype &dtype,
                      const void *data_ptr,
                      const int group_size)
        : dtype_(dtype), data_ptr_(data_ptr), group_size_(group_size) {}

    const core::Dtype dtype_;
    const void *data_ptr_;
    const int group_size_;
};

static core::Dtype GetDtypeFromPCDHeaderField(char type, int size) {
    char type_uppercase = std::toupper(type, std::locale());
    if (type_uppercase == 'I') {
        if (size == 1) return core::Dtype::Int8;
        if (size == 2) return core::Dtype::Int16;
        if (size == 4) return core::Dtype::Int32;
        if (size == 8)
            return core::Dtype::Int64;
        else
            utility::LogError("Unsupported size {} for data type {}.", size,
                              type);
    } else if (type_uppercase == 'U') {
        if (size == 1) return core::Dtype::UInt8;
        if (size == 2) return core::Dtype::UInt16;
        if (size == 4) return core::Dtype::UInt32;
        if (size == 8)
            return core::Dtype::UInt64;
        else
            utility::LogError("Unsupported size {} for data type {}.", size,
                              type);
    } else if (type_uppercase == 'F') {
        if (size == 4) return core::Dtype::Float32;
        if (size == 8)
            return core::Dtype::Float64;
        else
            utility::LogError("Unsupported size {} for data type {}.", size,
                              type);
    } else {
        utility::LogError("Unsupported data type {}.", type);
    }
}

static bool InitializeHeader(PCDHeader &header) {
    if (header.points <= 0 || header.pointsize <= 0) {
        utility::LogWarning("[Write PCD] PCD has no data.");
        return false;
    }
    if (header.fields.size() == 0 || header.pointsize <= 0) {
        utility::LogWarning("[Write PCD] PCD has no fields.");
        return false;
    }
    header.has_attr["positions"] = false;
    header.has_attr["normals"] = false;
    header.has_attr["colors"] = false;

    std::unordered_set<std::string> known_field;
    std::unordered_map<std::string, core::Dtype> field_dtype;

    for (const auto &field : header.fields) {
        if (field.name == "x" || field.name == "y" || field.name == "z" ||
            field.name == "normal_x" || field.name == "normal_y" ||
            field.name == "normal_z" || field.name == "rgb" ||
            field.name == "rgba") {
            known_field.insert(field.name);
            field_dtype[field.name] =
                    GetDtypeFromPCDHeaderField(field.type, field.size);
        } else {
            header.has_attr[field.name] = true;
            header.attr_dtype[field.name] =
                    GetDtypeFromPCDHeaderField(field.type, field.size);
        }
    }

    if (known_field.count("x") && known_field.count("y") &&
        known_field.count("z")) {
        if ((field_dtype["x"] == field_dtype["y"]) &&
            (field_dtype["x"] == field_dtype["z"])) {
            header.has_attr["positions"] = true;
            header.attr_dtype["positions"] = field_dtype["x"];
        } else {
            utility::LogWarning(
                    "[Write PCD] Dtype for positions data are not "
                    "same.");
            return false;
        }
    } else {
        utility::LogWarning(
                "[Write PCD] Fields for positions data are not "
                "complete.");
        return false;
    }

    if (known_field.count("normal_x") && known_field.count("normal_y") &&
        known_field.count("normal_z")) {
        if ((field_dtype["normal_x"] == field_dtype["normal_y"]) &&
            (field_dtype["normal_x"] == field_dtype["normal_z"])) {
            header.has_attr["normals"] = true;
            header.attr_dtype["normals"] = field_dtype["x"];
        } else {
            utility::LogWarning(
                    "[InitializeHeader] Dtype for normals data are not same.");
            return false;
        }
    }

    if (known_field.count("rgb")) {
        header.has_attr["colors"] = true;
        header.attr_dtype["colors"] = field_dtype["rgb"];
    } else if (known_field.count("rgba")) {
        header.has_attr["colors"] = true;
        header.attr_dtype["colors"] = field_dtype["rgba"];
    }

    return true;
}

static bool ReadPCDHeader(FILE *file, PCDHeader &header) {
    char line_buffer[DEFAULT_IO_BUFFER_SIZE];
    size_t specified_channel_count = 0;

    while (fgets(line_buffer, DEFAULT_IO_BUFFER_SIZE, file)) {
        std::string line(line_buffer);
        if (line == "") {
            continue;
        }
        std::vector<std::string> st = utility::SplitString(line, "\t\r\n ");
        std::stringstream sstream(line);
        sstream.imbue(std::locale::classic());
        std::string line_type;
        sstream >> line_type;
        if (line_type.substr(0, 1) == "#") {
        } else if (line_type.substr(0, 7) == "VERSION") {
            if (st.size() >= 2) {
                header.version = st[1];
            }
        } else if (line_type.substr(0, 6) == "FIELDS" ||
                   line_type.substr(0, 7) == "COLUMNS") {
            specified_channel_count = st.size() - 1;
            if (specified_channel_count == 0) {
                utility::LogWarning("[ReadPCDHeader] Bad PCD file format.");
                return false;
            }
            header.fields.resize(specified_channel_count);
            int count_offset = 0, offset = 0;
            for (size_t i = 0; i < specified_channel_count;
                 ++i, count_offset += 1, offset += 4) {
                header.fields[i].name = st[i + 1];
                header.fields[i].size = 4;
                header.fields[i].type = 'F';
                header.fields[i].count = 1;
                header.fields[i].count_offset = count_offset;
                header.fields[i].offset = offset;
            }
            header.elementnum = count_offset;
            header.pointsize = offset;
        } else if (line_type.substr(0, 4) == "SIZE") {
            if (specified_channel_count != st.size() - 1) {
                utility::LogWarning("[ReadPCDHeader] Bad PCD file format.");
                return false;
            }
            int offset = 0, col_type = 0;
            for (size_t i = 0; i < specified_channel_count;
                 ++i, offset += col_type) {
                sstream >> col_type;
                header.fields[i].size = col_type;
                header.fields[i].offset = offset;
            }
            header.pointsize = offset;
        } else if (line_type.substr(0, 4) == "TYPE") {
            if (specified_channel_count != st.size() - 1) {
                utility::LogWarning("[ReadPCDHeader] Bad PCD file format.");
                return false;
            }
            for (size_t i = 0; i < specified_channel_count; ++i) {
                header.fields[i].type = st[i + 1].c_str()[0];
            }
        } else if (line_type.substr(0, 5) == "COUNT") {
            if (specified_channel_count != st.size() - 1) {
                utility::LogWarning("[ReadPCDHeader] Bad PCD file format.");
                return false;
            }
            int count_offset = 0, offset = 0, col_count = 0;
            for (size_t i = 0; i < specified_channel_count; ++i) {
                sstream >> col_count;
                header.fields[i].count = col_count;
                header.fields[i].count_offset = count_offset;
                header.fields[i].offset = offset;
                count_offset += col_count;
                offset += col_count * header.fields[i].size;
            }
            header.elementnum = count_offset;
            header.pointsize = offset;
        } else if (line_type.substr(0, 5) == "WIDTH") {
            sstream >> header.width;
        } else if (line_type.substr(0, 6) == "HEIGHT") {
            sstream >> header.height;
            header.points = header.width * header.height;
        } else if (line_type.substr(0, 9) == "VIEWPOINT") {
            if (st.size() >= 2) {
                header.viewpoint = st[1];
            }
        } else if (line_type.substr(0, 6) == "POINTS") {
            sstream >> header.points;
        } else if (line_type.substr(0, 4) == "DATA") {
            header.datatype = PCDDataType::ASCII;
            if (st.size() >= 2) {
                if (st[1].substr(0, 17) == "binary_compressed") {
                    header.datatype = PCDDataType::BINARY_COMPRESSED;
                } else if (st[1].substr(0, 6) == "binary") {
                    header.datatype = PCDDataType::BINARY;
                }
            }
            break;
        }
    }
    if (!InitializeHeader(header)) {
        return false;
    }
    return true;
}

static void ReadASCIIPCDColorsFromField(ReadAttributePtr &attr,
                                        const PCLPointField &field,
                                        const char *data_ptr,
                                        const int index) {
    std::uint8_t *attr_data_ptr = static_cast<std::uint8_t *>(attr.data_ptr_) +
                                  index * attr.row_length_;

    if (field.size == 4) {
        std::uint8_t data[4] = {0};
        char *end;
        char type_uppercase = std::toupper(field.type, std::locale());
        if (type_uppercase == 'I') {
            std::int32_t value = std::strtol(data_ptr, &end, 0);
            std::memcpy(data, &value, sizeof(std::int32_t));
        } else if (type_uppercase == 'U') {
            std::uint32_t value = std::strtoul(data_ptr, &end, 0);
            std::memcpy(data, &value, sizeof(std::uint32_t));
        } else if (type_uppercase == 'F') {
            float value = std::strtof(data_ptr, &end);
            std::memcpy(data, &value, sizeof(float));
        }

        // color data is packed in BGR order.
        attr_data_ptr[0] = data[2];
        attr_data_ptr[1] = data[1];
        attr_data_ptr[2] = data[0];
    } else {
        attr_data_ptr[0] = 0;
        attr_data_ptr[1] = 0;
        attr_data_ptr[2] = 0;
    }
}

template <typename scalar_t>
static void UnpackASCIIPCDElement(scalar_t &data,
                                  const char *data_ptr) = delete;

template <>
void UnpackASCIIPCDElement<float>(float &data, const char *data_ptr) {
    char *end;
    data = std::strtof(data_ptr, &end);
}

template <>
void UnpackASCIIPCDElement<double>(double &data, const char *data_ptr) {
    char *end;
    data = std::strtod(data_ptr, &end);
}

template <>
void UnpackASCIIPCDElement<std::int8_t>(std::int8_t &data,
                                        const char *data_ptr) {
    char *end;
    data = static_cast<std::int8_t>(std::strtol(data_ptr, &end, 0));
}

template <>
void UnpackASCIIPCDElement<std::int16_t>(std::int16_t &data,
                                         const char *data_ptr) {
    char *end;
    data = static_cast<std::int16_t>(std::strtol(data_ptr, &end, 0));
}

template <>
void UnpackASCIIPCDElement<std::int32_t>(std::int32_t &data,
                                         const char *data_ptr) {
    char *end;
    data = static_cast<std::int32_t>(std::strtol(data_ptr, &end, 0));
}

template <>
void UnpackASCIIPCDElement<std::int64_t>(std::int64_t &data,
                                         const char *data_ptr) {
    char *end;
    data = std::strtol(data_ptr, &end, 0);
}

template <>
void UnpackASCIIPCDElement<std::uint8_t>(std::uint8_t &data,
                                         const char *data_ptr) {
    char *end;
    data = static_cast<std::uint8_t>(std::strtoul(data_ptr, &end, 0));
}

template <>
void UnpackASCIIPCDElement<std::uint16_t>(std::uint16_t &data,
                                          const char *data_ptr) {
    char *end;
    data = static_cast<std::uint16_t>(std::strtoul(data_ptr, &end, 0));
}

template <>
void UnpackASCIIPCDElement<std::uint32_t>(std::uint32_t &data,
                                          const char *data_ptr) {
    char *end;
    data = static_cast<std::uint32_t>(std::strtoul(data_ptr, &end, 0));
}

template <>
void UnpackASCIIPCDElement<std::uint64_t>(std::uint64_t &data,
                                          const char *data_ptr) {
    char *end;
    data = std::strtoul(data_ptr, &end, 0);
}

static void ReadASCIIPCDElementsFromField(ReadAttributePtr &attr,
                                          const PCLPointField &field,
                                          const char *data_ptr,
                                          const int index) {
    DISPATCH_DTYPE_TO_TEMPLATE(
            GetDtypeFromPCDHeaderField(field.type, field.size), [&] {
                scalar_t *attr_data_ptr =
                        static_cast<scalar_t *>(attr.data_ptr_) +
                        index * attr.row_length_ + attr.row_idx_;

                UnpackASCIIPCDElement<scalar_t>(attr_data_ptr[0], data_ptr);
            });
}

static void ReadBinaryPCDColorsFromField(ReadAttributePtr &attr,
                                         const PCLPointField &field,
                                         const void *data_ptr,
                                         const int index) {
    std::uint8_t *attr_data_ptr = static_cast<std::uint8_t *>(attr.data_ptr_) +
                                  index * attr.row_length_;

    if (field.size == 4) {
        std::uint8_t data[4] = {0};
        std::memcpy(data, data_ptr, 4 * sizeof(std::uint8_t));

        // color data is packed in BGR order.
        attr_data_ptr[0] = data[2];
        attr_data_ptr[1] = data[1];
        attr_data_ptr[2] = data[0];
    } else {
        attr_data_ptr[0] = 0;
        attr_data_ptr[1] = 0;
        attr_data_ptr[2] = 0;
    }
}

static void ReadBinaryPCDElementsFromField(ReadAttributePtr &attr,
                                           const PCLPointField &field,
                                           const void *data_ptr,
                                           const int index) {
    DISPATCH_DTYPE_TO_TEMPLATE(
            GetDtypeFromPCDHeaderField(field.type, field.size), [&] {
                scalar_t *attr_data_ptr =
                        static_cast<scalar_t *>(attr.data_ptr_) +
                        index * attr.row_length_ + attr.row_idx_;

                std::memcpy(attr_data_ptr, data_ptr, sizeof(scalar_t));
            });
}

static bool ReadPCDData(FILE *file,
                        PCDHeader &header,
                        t::geometry::PointCloud &pointcloud,
                        const ReadPointCloudOption &params) {
    // The header should have been checked
    pointcloud.Clear();

    std::unordered_map<std::string, ReadAttributePtr> map_field_to_attr_ptr;

    if (header.has_attr["positions"]) {
        pointcloud.SetPointPositions(core::Tensor::Empty(
                {header.points, 3}, header.attr_dtype["positions"]));

        void *data_ptr = pointcloud.GetPointPositions().GetDataPtr();
        ReadAttributePtr position_x(data_ptr, 0, 3, header.points);
        ReadAttributePtr position_y(data_ptr, 1, 3, header.points);
        ReadAttributePtr position_z(data_ptr, 2, 3, header.points);

        map_field_to_attr_ptr.emplace(std::string("x"), position_x);
        map_field_to_attr_ptr.emplace(std::string("y"), position_y);
        map_field_to_attr_ptr.emplace(std::string("z"), position_z);
    } else {
        utility::LogWarning(
                "[ReadPCDData] Fields for point data are not complete.");
        return false;
    }
    if (header.has_attr["normals"]) {
        pointcloud.SetPointNormals(core::Tensor::Empty(
                {header.points, 3}, header.attr_dtype["normals"]));

        void *data_ptr = pointcloud.GetPointNormals().GetDataPtr();
        ReadAttributePtr normal_x(data_ptr, 0, 3, header.points);
        ReadAttributePtr normal_y(data_ptr, 1, 3, header.points);
        ReadAttributePtr normal_z(data_ptr, 2, 3, header.points);

        map_field_to_attr_ptr.emplace(std::string("normal_x"), normal_x);
        map_field_to_attr_ptr.emplace(std::string("normal_y"), normal_y);
        map_field_to_attr_ptr.emplace(std::string("normal_z"), normal_z);
    }
    if (header.has_attr["colors"]) {
        // Colors stored in a PCD file is ALWAYS in UInt8 format.
        // However it is stored as a single packed floating value.
        pointcloud.SetPointColors(
                core::Tensor::Empty({header.points, 3}, core::UInt8));

        void *data_ptr = pointcloud.GetPointColors().GetDataPtr();
        ReadAttributePtr colors(data_ptr, 0, 3, header.points);

        map_field_to_attr_ptr.emplace(std::string("colors"), colors);
    }

    // PCLPointField
    for (const auto &field : header.fields) {
        if (header.has_attr[field.name] && field.name != "x" &&
            field.name != "y" && field.name != "z" &&
            field.name != "normal_x" && field.name != "normal_y" &&
            field.name != "normal_z" && field.name != "rgb" &&
            field.name != "rgba") {
            pointcloud.SetPointAttr(
                    field.name,
                    core::Tensor::Empty({header.points, 1},
                                        header.attr_dtype[field.name]));

            void *data_ptr = pointcloud.GetPointAttr(field.name).GetDataPtr();
            ReadAttributePtr attr(data_ptr, 0, 1, header.points);

            map_field_to_attr_ptr.emplace(field.name, attr);
        }
    }

    utility::CountingProgressReporter reporter(params.update_progress);
    reporter.SetTotal(header.points);

    if (header.datatype == PCDDataType::ASCII) {
        char line_buffer[DEFAULT_IO_BUFFER_SIZE];
        int idx = 0;
        while (fgets(line_buffer, DEFAULT_IO_BUFFER_SIZE, file) &&
               idx < header.points) {
            std::string line(line_buffer);
            std::vector<std::string> strs =
                    utility::SplitString(line, "\t\r\n ");
            if ((int)strs.size() < header.elementnum) {
                continue;
            }
            for (size_t i = 0; i < header.fields.size(); ++i) {
                const auto &field = header.fields[i];
                if (field.name == "rgb" || field.name == "rgba") {
                    ReadASCIIPCDColorsFromField(
                            map_field_to_attr_ptr["colors"], field,
                            strs[field.count_offset].c_str(), idx);
                } else {
                    ReadASCIIPCDElementsFromField(
                            map_field_to_attr_ptr[field.name], field,
                            strs[field.count_offset].c_str(), idx);
                }
            }
            ++idx;
            if (idx % 1000 == 0) {
                reporter.Update(idx);
            }
        }
    } else if (header.datatype == PCDDataType::BINARY) {
        std::unique_ptr<char[]> buffer(new char[header.pointsize]);
        for (int i = 0; i < header.points; ++i) {
            if (fread(buffer.get(), header.pointsize, 1, file) != 1) {
                utility::LogWarning(
                        "[ReadPCDData] Failed to read data record.");
                pointcloud.Clear();
                return false;
            }
            for (const auto &field : header.fields) {
                if (field.name == "rgb" || field.name == "rgba") {
                    ReadBinaryPCDColorsFromField(
                            map_field_to_attr_ptr["colors"], field,
                            buffer.get() + field.offset, i);
                } else {
                    ReadBinaryPCDElementsFromField(
                            map_field_to_attr_ptr[field.name], field,
                            buffer.get() + field.offset, i);
                }
            }
            if (i % 1000 == 0) {
                reporter.Update(i);
            }
        }
    } else if (header.datatype == PCDDataType::BINARY_COMPRESSED) {
        double reporter_total = 100.0;
        reporter.SetTotal(int(reporter_total));
        reporter.Update(int(reporter_total * 0.01));
        std::uint32_t compressed_size;
        std::uint32_t uncompressed_size;
        if (fread(&compressed_size, sizeof(compressed_size), 1, file) != 1) {
            utility::LogWarning("[ReadPCDData] Failed to read data record.");
            pointcloud.Clear();
            return false;
        }
        if (fread(&uncompressed_size, sizeof(uncompressed_size), 1, file) !=
            1) {
            utility::LogWarning("[ReadPCDData] Failed to read data record.");
            pointcloud.Clear();
            return false;
        }
        utility::LogDebug(
                "PCD data with {:d} compressed size, and {:d} uncompressed "
                "size.",
                compressed_size, uncompressed_size);
        std::unique_ptr<char[]> buffer_compressed(new char[compressed_size]);
        reporter.Update(int(reporter_total * .1));
        if (fread(buffer_compressed.get(), 1, compressed_size, file) !=
            compressed_size) {
            utility::LogWarning("[ReadPCDData] Failed to read data record.");
            pointcloud.Clear();
            return false;
        }
        std::unique_ptr<char[]> buffer(new char[uncompressed_size]);
        reporter.Update(int(reporter_total * .2));
        if (lzf_decompress(buffer_compressed.get(),
                           (unsigned int)compressed_size, buffer.get(),
                           (unsigned int)uncompressed_size) !=
            uncompressed_size) {
            utility::LogWarning("[ReadPCDData] Uncompression failed.");
            pointcloud.Clear();
            return false;
        }
        for (const auto &field : header.fields) {
            const char *base_ptr = buffer.get() + field.offset * header.points;
            double progress =
                    double(base_ptr - buffer.get()) / uncompressed_size;
            reporter.Update(int(reporter_total * (progress + .2)));
            if (field.name == "rgb" || field.name == "rgba") {
                for (int i = 0; i < header.points; ++i) {
                    ReadBinaryPCDColorsFromField(
                            map_field_to_attr_ptr["colors"], field,
                            base_ptr + i * field.size * field.count, i);
                }
            } else {
                for (int i = 0; i < header.points; ++i) {
                    ReadBinaryPCDElementsFromField(
                            map_field_to_attr_ptr[field.name], field,
                            base_ptr + i * field.size * field.count, i);
                }
            }
        }
    }
    reporter.Finish();
    return true;
}

// Write functions.

static void SetPCDHeaderFieldTypeAndSizeFromDtype(const core::Dtype &dtype,
                                                  PCLPointField &field) {
    if (dtype == core::Int8) {
        field.type = 'I';
        field.size = 1;
    } else if (dtype == core::Int16) {
        field.type = 'I';
        field.size = 2;
    } else if (dtype == core::Int32) {
        field.type = 'I';
        field.size = 4;
    } else if (dtype == core::Int64) {
        field.type = 'I';
        field.size = 8;
    } else if (dtype == core::UInt8) {
        field.type = 'U';
        field.size = 1;
    } else if (dtype == core::UInt16) {
        field.type = 'U';
        field.size = 2;
    } else if (dtype == core::UInt32) {
        field.type = 'U';
        field.size = 4;
    } else if (dtype == core::UInt64) {
        field.type = 'U';
        field.size = 8;
    } else if (dtype == core::Float32) {
        field.type = 'F';
        field.size = 4;
    } else if (dtype == core::Float64) {
        field.type = 'F';
        field.size = 8;
    } else {
        utility::LogError("Unsupported data type.");
    }
}

static bool GenerateHeader(const t::geometry::PointCloud &pointcloud,
                           const bool write_ascii,
                           const bool compressed,
                           PCDHeader &header) {
    if (!pointcloud.HasPointPositions()) {
        return false;
    }

    header.version = "0.7";
    header.width = static_cast<int>(pointcloud.GetPointPositions().GetLength());
    header.height = 1;
    header.points = header.width;
    header.fields.clear();

    PCLPointField field_x, field_y, field_z;
    field_x.name = "x";
    field_x.count = 1;
    SetPCDHeaderFieldTypeAndSizeFromDtype(
            pointcloud.GetPointPositions().GetDtype(), field_x);
    header.fields.push_back(field_x);

    field_y = field_x;
    field_y.name = "y";
    header.fields.push_back(field_y);

    field_z = field_x;
    field_z.name = "z";
    header.fields.push_back(field_z);

    header.elementnum = 3 * field_x.count;
    header.pointsize = 3 * field_x.size;

    if (pointcloud.HasPointNormals()) {
        PCLPointField field_normal_x, field_normal_y, field_normal_z;

        field_normal_x.name = "normal_x";
        field_normal_x.count = 1;
        SetPCDHeaderFieldTypeAndSizeFromDtype(
                pointcloud.GetPointPositions().GetDtype(), field_normal_x);
        header.fields.push_back(field_normal_x);

        field_normal_y = field_normal_x;
        field_normal_y.name = "normal_y";
        header.fields.push_back(field_normal_y);

        field_normal_z = field_normal_x;
        field_normal_z.name = "normal_z";
        header.fields.push_back(field_normal_z);

        header.elementnum += 3 * field_normal_x.count;
        header.pointsize += 3 * field_normal_x.size;
    }
    if (pointcloud.HasPointColors()) {
        PCLPointField field_colors;
        field_colors.name = "rgb";
        field_colors.count = 1;
        field_colors.type = 'F';
        field_colors.size = 4;
        header.fields.push_back(field_colors);

        header.elementnum++;
        header.pointsize += 4;
    }

    // Custom attribute support of shape {num_points, 1}.
    for (auto &kv : pointcloud.GetPointAttr()) {
        if (kv.first != "positions" && kv.first != "normals" &&
            kv.first != "colors") {
            if (kv.second.GetShape() ==
                core::SizeVector(
                        {pointcloud.GetPointPositions().GetLength(), 1})) {
                PCLPointField field_custom_attr;
                field_custom_attr.name = kv.first;
                field_custom_attr.count = 1;
                SetPCDHeaderFieldTypeAndSizeFromDtype(kv.second.GetDtype(),
                                                      field_custom_attr);
                header.fields.push_back(field_custom_attr);

                header.elementnum++;
                header.pointsize += field_custom_attr.size;
            } else {
                utility::LogWarning(
                        "Write PCD : Skipping {} attribute. PointCloud "
                        "contains {} attribute which is not supported by PCD "
                        "IO. Only points, normals, colors and attributes with "
                        "shape (num_points, 1) are supported. Expected shape: "
                        "{} but got {}.",
                        kv.first, kv.first,
                        core::SizeVector(
                                {pointcloud.GetPointPositions().GetLength(), 1})
                                .ToString(),
                        kv.second.GetShape().ToString());
            }
        }
    }

    if (write_ascii) {
        header.datatype = PCDDataType::ASCII;
    } else {
        if (compressed) {
            header.datatype = PCDDataType::BINARY_COMPRESSED;
        } else {
            header.datatype = PCDDataType::BINARY;
        }
    }
    return true;
}

static bool WritePCDHeader(FILE *file, const PCDHeader &header) {
    fprintf(file, "# .PCD v%s - Point Cloud Data file format\n",
            header.version.c_str());
    fprintf(file, "VERSION %s\n", header.version.c_str());
    fprintf(file, "FIELDS");
    for (const auto &field : header.fields) {
        fprintf(file, " %s", field.name.c_str());
    }
    fprintf(file, "\n");
    fprintf(file, "SIZE");
    for (const auto &field : header.fields) {
        fprintf(file, " %d", field.size);
    }
    fprintf(file, "\n");
    fprintf(file, "TYPE");
    for (const auto &field : header.fields) {
        fprintf(file, " %c", field.type);
    }
    fprintf(file, "\n");
    fprintf(file, "COUNT");
    for (const auto &field : header.fields) {
        fprintf(file, " %d", field.count);
    }
    fprintf(file, "\n");
    fprintf(file, "WIDTH %d\n", header.width);
    fprintf(file, "HEIGHT %d\n", header.height);
    fprintf(file, "VIEWPOINT 0 0 0 1 0 0 0\n");
    fprintf(file, "POINTS %d\n", header.points);

    switch (header.datatype) {
        case PCDDataType::BINARY:
            fprintf(file, "DATA binary\n");
            break;
        case PCDDataType::BINARY_COMPRESSED:
            fprintf(file, "DATA binary_compressed\n");
            break;
        case PCDDataType::ASCII:
        default:
            fprintf(file, "DATA ascii\n");
            break;
    }
    return true;
}

template <typename scalar_t>
static void ColorToUint8(const scalar_t *input_color,
                         std::uint8_t *output_color) {
    utility::LogError(
            "Color format not supported. Supported color format includes "
            "Float32, Float64, UInt8, UInt16, UInt32.");
}

template <>
void ColorToUint8<float>(const float *input_color, std::uint8_t *output_color) {
    const float normalisation_factor =
            static_cast<float>(std::numeric_limits<std::uint8_t>::max());
    for (int i = 0; i < 3; ++i) {
        output_color[i] = static_cast<std::uint8_t>(
                std::round(std::min(1.f, std::max(0.f, input_color[2 - i])) *
                           normalisation_factor));
    }
    output_color[3] = 0;
}

template <>
void ColorToUint8<double>(const double *input_color,
                          std::uint8_t *output_color) {
    const double normalisation_factor =
            static_cast<double>(std::numeric_limits<std::uint8_t>::max());
    for (int i = 0; i < 3; ++i) {
        output_color[i] = static_cast<std::uint8_t>(
                std::round(std::min(1., std::max(0., input_color[2 - i])) *
                           normalisation_factor));
    }
    output_color[3] = 0;
}

template <>
void ColorToUint8<std::uint8_t>(const std::uint8_t *input_color,
                                std::uint8_t *output_color) {
    for (int i = 0; i < 3; ++i) {
        output_color[i] = input_color[2 - i];
    }
    output_color[3] = 0;
}

template <>
void ColorToUint8<std::uint16_t>(const std::uint16_t *input_color,
                                 std::uint8_t *output_color) {
    const float normalisation_factor =
            static_cast<float>(std::numeric_limits<std::uint8_t>::max()) /
            static_cast<float>(std::numeric_limits<std::uint16_t>::max());
    for (int i = 0; i < 3; ++i) {
        output_color[i] = static_cast<std::uint16_t>(input_color[2 - i] *
                                                     normalisation_factor);
    }
    output_color[3] = 0;
}

template <>
void ColorToUint8<std::uint32_t>(const std::uint32_t *input_color,
                                 std::uint8_t *output_color) {
    const float normalisation_factor =
            static_cast<float>(std::numeric_limits<std::uint8_t>::max()) /
            static_cast<float>(std::numeric_limits<std::uint32_t>::max());
    for (int i = 0; i < 3; ++i) {
        output_color[i] = static_cast<std::uint32_t>(input_color[2 - i] *
                                                     normalisation_factor);
    }
    output_color[3] = 0;
}

static core::Tensor PackColorsToFloat(const core::Tensor &colors_contiguous) {
    core::Tensor packed_color =
            core::Tensor::Empty({colors_contiguous.GetLength(), 1},
                                core::Float32, core::Device("CPU:0"));
    auto packed_color_ptr = packed_color.GetDataPtr<float>();

    DISPATCH_DTYPE_TO_TEMPLATE(colors_contiguous.GetDtype(), [&]() {
        auto colors_ptr = colors_contiguous.GetDataPtr<scalar_t>();
        core::ParallelFor(core::Device("CPU:0"), colors_contiguous.GetLength(),
                          [&](std::int64_t workload_idx) {
                              std::uint8_t rgba[4] = {0};
                              ColorToUint8<scalar_t>(
                                      colors_ptr + 3 * workload_idx, rgba);
                              float val = 0;
                              std::memcpy(&val, rgba, 4 * sizeof(std::uint8_t));
                              packed_color_ptr[workload_idx] = val;
                          });
    });

    return packed_color;
}

template <typename scalar_t>
static int WriteElementDataToFileASCII(const scalar_t &data,
                                       FILE *file) = delete;

template <>
int WriteElementDataToFileASCII<float>(const float &data, FILE *file) {
    return fprintf(file, "%.10g ", data);
}

template <>
int WriteElementDataToFileASCII<double>(const double &data, FILE *file) {
    return fprintf(file, "%.10g ", data);
}

template <>
int WriteElementDataToFileASCII<std::int8_t>(const std::int8_t &data,
                                             FILE *file) {
    return fprintf(file, "%" PRId8 " ", data);
}

template <>
int WriteElementDataToFileASCII<std::int16_t>(const std::int16_t &data,
                                              FILE *file) {
    return fprintf(file, "%" PRId16 " ", data);
}

template <>
int WriteElementDataToFileASCII<std::int32_t>(const std::int32_t &data,
                                              FILE *file) {
    return fprintf(file, "%" PRId32 " ", data);
}

template <>
int WriteElementDataToFileASCII<std::int64_t>(const std::int64_t &data,
                                              FILE *file) {
    return fprintf(file, "%" PRId64 " ", data);
}

template <>
int WriteElementDataToFileASCII<std::uint8_t>(const std::uint8_t &data,
                                              FILE *file) {
    return fprintf(file, "%" PRIu8 " ", data);
}

template <>
int WriteElementDataToFileASCII<std::uint16_t>(const std::uint16_t &data,
                                               FILE *file) {
    return fprintf(file, "%" PRIu16 " ", data);
}

template <>
int WriteElementDataToFileASCII<std::uint32_t>(const std::uint32_t &data,
                                               FILE *file) {
    return fprintf(file, "%" PRIu32 " ", data);
}

template <>
int WriteElementDataToFileASCII<std::uint64_t>(const std::uint64_t &data,
                                               FILE *file) {
    return fprintf(file, "%" PRIu64 " ", data);
}

static bool WritePCDData(FILE *file,
                         const PCDHeader &header,
                         const geometry::PointCloud &pointcloud,
                         const WritePointCloudOption &params) {
    if (pointcloud.IsEmpty()) {
        utility::LogWarning("Write PLY failed: point cloud has 0 points.");
        return false;
    }

    // TODO: Add device transfer in tensor map and use it here.
    geometry::TensorMap t_map(pointcloud.GetPointAttr().Contiguous());
    const std::int64_t num_points = static_cast<std::int64_t>(
            pointcloud.GetPointPositions().GetLength());

    std::vector<WriteAttributePtr> attribute_ptrs;

    attribute_ptrs.emplace_back(t_map["positions"].GetDtype(),
                                t_map["positions"].GetDataPtr(), 3);

    if (pointcloud.HasPointNormals()) {
        attribute_ptrs.emplace_back(t_map["normals"].GetDtype(),
                                    t_map["normals"].GetDataPtr(), 3);
    }

    if (pointcloud.HasPointColors()) {
        t_map["colors"] = PackColorsToFloat(t_map["colors"]);
        attribute_ptrs.emplace_back(core::Float32, t_map["colors"].GetDataPtr(),
                                    1);
    }

    // Sanity check for the attributes is done before adding it to the
    // `header.fields`.
    for (auto &field : header.fields) {
        if (field.name != "x" && field.name != "y" && field.name != "z" &&
            field.name != "normal_x" && field.name != "normal_y" &&
            field.name != "normal_z" && field.name != "rgb" &&
            field.name != "rgba" && field.count == 1) {
            attribute_ptrs.emplace_back(t_map[field.name].GetDtype(),
                                        t_map[field.name].GetDataPtr(), 1);
        }
    }

    utility::CountingProgressReporter reporter(params.update_progress);
    reporter.SetTotal(num_points);
    if (header.datatype == PCDDataType::ASCII) {
        for (std::int64_t i = 0; i < num_points; ++i) {
            for (auto &it : attribute_ptrs) {
                DISPATCH_DTYPE_TO_TEMPLATE(it.dtype_, [&]() {
                    const scalar_t *data_ptr =
                            static_cast<const scalar_t *>(it.data_ptr_);

                    for (int idx_offset = it.group_size_ * i;
                         idx_offset < it.group_size_ * (i + 1); ++idx_offset) {
                        WriteElementDataToFileASCII<scalar_t>(
                                data_ptr[idx_offset], file);
                    }
                });
            }

            fprintf(file, "\n");
            if (i % 1000 == 0) {
                reporter.Update(i);
            }
        }
    } else if (header.datatype == PCDDataType::BINARY) {
        std::vector<char> buffer((header.pointsize * header.points));
        std::uint32_t buffer_index = 0;
        for (std::int64_t i = 0; i < num_points; ++i) {
            for (auto &it : attribute_ptrs) {
                DISPATCH_DTYPE_TO_TEMPLATE(it.dtype_, [&]() {
                    const scalar_t *data_ptr =
                            static_cast<const scalar_t *>(it.data_ptr_);

                    for (int idx_offset = it.group_size_ * i;
                         idx_offset < it.group_size_ * (i + 1); ++idx_offset) {
                        std::memcpy(buffer.data() + buffer_index,
                                    reinterpret_cast<const char *>(
                                            &data_ptr[idx_offset]),
                                    sizeof(scalar_t));
                        buffer_index += sizeof(scalar_t);
                    }
                });
            }

            if (i % 1000 == 0) {
                reporter.Update(i);
            }
        }

        fwrite(buffer.data(), sizeof(char), buffer.size(), file);
    } else if (header.datatype == PCDDataType::BINARY_COMPRESSED) {
        // BINARY_COMPRESSED data contains attributes in column layout
        // for better compression.
        // For example instead of X Y Z NX NY NZ X Y Z NX NY NZ, the data is
        // stored as X X Y Y Z Z NX NX NY NY NZ NZ.

        const std::int64_t report_total = attribute_ptrs.size() * 2;
        // 0%-50% packing into buffer
        // 50%-75% compressing buffer
        // 75%-100% writing compressed buffer
        reporter.SetTotal(report_total);

        const std::uint32_t buffer_size_in_bytes =
                header.pointsize * header.points;
        std::vector<char> buffer(buffer_size_in_bytes);
        std::vector<char> buffer_compressed(2 * buffer_size_in_bytes);

        std::uint32_t buffer_index = 0;
        std::int64_t count = 0;
        for (auto &it : attribute_ptrs) {
            DISPATCH_DTYPE_TO_TEMPLATE(it.dtype_, [&]() {
                const scalar_t *data_ptr =
                        static_cast<const scalar_t *>(it.data_ptr_);

                for (int idx_offset = 0; idx_offset < it.group_size_;
                     ++idx_offset) {
                    for (std::int64_t i = 0; i < num_points; ++i) {
                        std::memcpy(buffer.data() + buffer_index,
                                    reinterpret_cast<const char *>(
                                            &data_ptr[i * it.group_size_ +
                                                      idx_offset]),
                                    sizeof(scalar_t));
                        buffer_index += sizeof(scalar_t);
                    }
                }
            });

            reporter.Update(count++);
        }

        std::uint32_t size_compressed = lzf_compress(
                buffer.data(), buffer_size_in_bytes, buffer_compressed.data(),
                buffer_size_in_bytes * 2);
        if (size_compressed == 0) {
            utility::LogWarning("[WritePCDData] Failed to compress data.");
            return false;
        }

        utility::LogDebug(
                "[WritePCDData] {:d} bytes data compressed into {:d} bytes.",
                buffer_size_in_bytes, size_compressed);

        reporter.Update(static_cast<std::int64_t>(report_total * 0.75));

        fwrite(&size_compressed, sizeof(size_compressed), 1, file);
        fwrite(&buffer_size_in_bytes, sizeof(buffer_size_in_bytes), 1, file);
        fwrite(buffer_compressed.data(), 1, size_compressed, file);
    }
    reporter.Finish();
    return true;
}

bool ReadPointCloudFromPCD(const std::string &filename,
                           t::geometry::PointCloud &pointcloud,
                           const ReadPointCloudOption &params) {
    PCDHeader header;
    FILE *file = utility::filesystem::FOpen(filename.c_str(), "rb");
    if (file == NULL) {
        utility::LogWarning("Read PCD failed: unable to open file: {}",
                            filename);
        return false;
    }

    if (!ReadPCDHeader(file, header)) {
        utility::LogWarning("Read PCD failed: unable to parse header.");
        fclose(file);
        return false;
    }
    utility::LogDebug(
            "PCD header indicates {:d} fields, {:d} bytes per point, and {:d} "
            "points in total.",
            (int)header.fields.size(), header.pointsize, header.points);
    for (const auto &field : header.fields) {
        utility::LogDebug("{}, {}, {:d}, {:d}, {:d}", field.name.c_str(),
                          field.type, field.size, field.count, field.offset);
    }
    utility::LogDebug("Compression method is {:d}.", (int)header.datatype);
    utility::LogDebug("Points: {};  normals: {};  colors: {}",
                      header.has_attr["positions"] ? "yes" : "no",
                      header.has_attr["normals"] ? "yes" : "no",
                      header.has_attr["colors"] ? "yes" : "no");
    if (!ReadPCDData(file, header, pointcloud, params)) {
        utility::LogWarning("Read PCD failed: unable to read data.");
        fclose(file);
        return false;
    }
    fclose(file);
    return true;
}

bool WritePointCloudToPCD(const std::string &filename,
                          const geometry::PointCloud &pointcloud,
                          const WritePointCloudOption &params) {
    core::AssertTensorDevice(pointcloud.GetPointPositions(),
                             core::Device("CPU:0"));

    PCDHeader header;
    if (!GenerateHeader(pointcloud, bool(params.write_ascii),
                        bool(params.compressed), header)) {
        utility::LogWarning("Write PCD failed: unable to generate header.");
        return false;
    }
    FILE *file = utility::filesystem::FOpen(filename.c_str(), "wb");
    if (file == NULL) {
        utility::LogWarning("Write PCD failed: unable to open file.");
        return false;
    }
    if (!WritePCDHeader(file, header)) {
        utility::LogWarning("Write PCD failed: unable to write header.");
        fclose(file);
        return false;
    }
    if (!WritePCDData(file, header, pointcloud, params)) {
        utility::LogWarning("Write PCD failed: unable to write data.");
        fclose(file);
        return false;
    }
    fclose(file);
    return true;
}

}  // namespace io
}  // namespace t
}  // namespace open3d