###############################################################################
#
# Workbook - A class for writing the Excel XLSX Workbook file.
#
# SPDX-License-Identifier: BSD-2-Clause
# Copyright 2013-2023, John McNamara, jmcnamara@cpan.org
#

# Standard packages.
import hashlib
import operator
import os
import re
import time
from datetime import datetime, timezone
from decimal import Decimal
from fractions import Fraction
from struct import unpack
from warnings import warn
from zipfile import ZipFile, ZipInfo, ZIP_DEFLATED, LargeZipFile


# Package imports.
from . import xmlwriter
from .worksheet import Worksheet
from .chartsheet import Chartsheet
from .sharedstrings import SharedStringTable
from .format import Format
from .packager import Packager
from .utility import xl_cell_to_rowcol
from .chart_area import ChartArea
from .chart_bar import ChartBar
from .chart_column import ChartColumn
from .chart_doughnut import ChartDoughnut
from .chart_line import ChartLine
from .chart_pie import ChartPie
from .chart_radar import ChartRadar
from .chart_scatter import ChartScatter
from .chart_stock import ChartStock
from .exceptions import InvalidWorksheetName
from .exceptions import DuplicateWorksheetName
from .exceptions import UndefinedImageSize
from .exceptions import UnsupportedImageFormat
from .exceptions import FileCreateError
from .exceptions import FileSizeError


class Workbook(xmlwriter.XMLwriter):
    """
    A class for writing the Excel XLSX Workbook file.


    """

    ###########################################################################
    #
    # Public API.
    #
    ###########################################################################
    chartsheet_class = Chartsheet
    worksheet_class = Worksheet

    def __init__(self, filename=None, options=None):
        """
        Constructor.

        """
        if options is None:
            options = {}

        super(Workbook, self).__init__()

        self.filename = filename

        self.tmpdir = options.get("tmpdir", None)
        self.date_1904 = options.get("date_1904", False)
        self.strings_to_numbers = options.get("strings_to_numbers", False)
        self.strings_to_formulas = options.get("strings_to_formulas", True)
        self.strings_to_urls = options.get("strings_to_urls", True)
        self.nan_inf_to_errors = options.get("nan_inf_to_errors", False)
        self.default_date_format = options.get("default_date_format", None)
        self.constant_memory = options.get("constant_memory", False)
        self.in_memory = options.get("in_memory", False)
        self.excel2003_style = options.get("excel2003_style", False)
        self.remove_timezone = options.get("remove_timezone", False)
        self.use_future_functions = options.get("use_future_functions", False)
        self.default_format_properties = options.get("default_format_properties", {})

        self.max_url_length = options.get("max_url_length", 2079)
        if self.max_url_length < 255:
            self.max_url_length = 2079

        if options.get("use_zip64"):
            self.allow_zip64 = True
        else:
            self.allow_zip64 = False

        self.worksheet_meta = WorksheetMeta()
        self.selected = 0
        self.fileclosed = 0
        self.filehandle = None
        self.internal_fh = 0
        self.sheet_name = "Sheet"
        self.chart_name = "Chart"
        self.sheetname_count = 0
        self.chartname_count = 0
        self.worksheets_objs = []
        self.charts = []
        self.drawings = []
        self.sheetnames = {}
        self.formats = []
        self.xf_formats = []
        self.xf_format_indices = {}
        self.dxf_formats = []
        self.dxf_format_indices = {}
        self.palette = []
        self.font_count = 0
        self.num_formats = []
        self.defined_names = []
        self.named_ranges = []
        self.custom_colors = []
        self.doc_properties = {}
        self.custom_properties = []
        self.createtime = datetime.now(timezone.utc)
        self.num_vml_files = 0
        self.num_comment_files = 0
        self.x_window = 240
        self.y_window = 15
        self.window_width = 16095
        self.window_height = 9660
        self.tab_ratio = 600
        self.str_table = SharedStringTable()
        self.vba_project = None
        self.vba_project_is_stream = False
        self.vba_project_signature = None
        self.vba_project_signature_is_stream = False
        self.vba_codename = None
        self.image_types = {}
        self.images = []
        self.border_count = 0
        self.fill_count = 0
        self.drawing_count = 0
        self.calc_mode = "auto"
        self.calc_on_load = True
        self.calc_id = 124519
        self.has_comments = False
        self.read_only = 0
        self.has_metadata = False

        # We can't do 'constant_memory' mode while doing 'in_memory' mode.
        if self.in_memory:
            self.constant_memory = False

        # Add the default cell format.
        if self.excel2003_style:
            self.add_format({"xf_index": 0, "font_family": 0})
        else:
            self.add_format({"xf_index": 0})

        # Add a default URL format.
        self.default_url_format = self.add_format({"hyperlink": True})

        # Add the default date format.
        if self.default_date_format is not None:
            self.default_date_format = self.add_format(
                {"num_format": self.default_date_format}
            )

    def __enter__(self):
        """Return self object to use with "with" statement."""
        return self

    def __exit__(self, type, value, traceback):
        """Close workbook when exiting "with" statement."""
        self.close()

    def add_worksheet(self, name=None, worksheet_class=None):
        """
        Add a new worksheet to the Excel workbook.

        Args:
            name: The worksheet name. Defaults to 'Sheet1', etc.

        Returns:
            Reference to a worksheet object.

        """
        if worksheet_class is None:
            worksheet_class = self.worksheet_class

        return self._add_sheet(name, worksheet_class=worksheet_class)

    def add_chartsheet(self, name=None, chartsheet_class=None):
        """
        Add a new chartsheet to the Excel workbook.

        Args:
            name: The chartsheet name. Defaults to 'Sheet1', etc.

        Returns:
            Reference to a chartsheet object.

        """
        if chartsheet_class is None:
            chartsheet_class = self.chartsheet_class

        return self._add_sheet(name, worksheet_class=chartsheet_class)

    def add_format(self, properties=None):
        """
        Add a new Format to the Excel Workbook.

        Args:
            properties: The format properties.

        Returns:
            Reference to a Format object.

        """
        format_properties = self.default_format_properties.copy()

        if self.excel2003_style:
            format_properties = {"font_name": "Arial", "font_size": 10, "theme": 1 * -1}

        if properties:
            format_properties.update(properties)

        xf_format = Format(
            format_properties, self.xf_format_indices, self.dxf_format_indices
        )

        # Store the format reference.
        self.formats.append(xf_format)

        return xf_format

    def add_chart(self, options):
        """
        Create a chart object.

        Args:
            options: The chart type and subtype options.

        Returns:
            Reference to a Chart object.

        """

        # Type must be specified so we can create the required chart instance.
        chart_type = options.get("type")
        if chart_type is None:
            warn("Chart type must be defined in add_chart()")
            return

        if chart_type == "area":
            chart = ChartArea(options)
        elif chart_type == "bar":
            chart = ChartBar(options)
        elif chart_type == "column":
            chart = ChartColumn(options)
        elif chart_type == "doughnut":
            chart = ChartDoughnut(options)
        elif chart_type == "line":
            chart = ChartLine(options)
        elif chart_type == "pie":
            chart = ChartPie(options)
        elif chart_type == "radar":
            chart = ChartRadar(options)
        elif chart_type == "scatter":
            chart = ChartScatter(options)
        elif chart_type == "stock":
            chart = ChartStock(options)
        else:
            warn("Unknown chart type '%s' in add_chart()" % chart_type)
            return

        # Set the embedded chart name if present.
        if "name" in options:
            chart.chart_name = options["name"]

        chart.embedded = True
        chart.date_1904 = self.date_1904
        chart.remove_timezone = self.remove_timezone

        self.charts.append(chart)

        return chart

    def add_vba_project(self, vba_project, is_stream=False):
        """
        Add a vbaProject binary to the Excel workbook.

        Args:
            vba_project: The vbaProject binary file name.
            is_stream:   vba_project is an in memory byte stream.

        Returns:
            Nothing.

        """
        if not is_stream and not os.path.exists(vba_project):
            warn("VBA project binary file '%s' not found." % vba_project)
            return -1

        if self.vba_codename is None:
            self.vba_codename = "ThisWorkbook"

        self.vba_project = vba_project
        self.vba_project_is_stream = is_stream

    def add_signed_vba_project(
        self, vba_project, signature, project_is_stream=False, signature_is_stream=False
    ):
        """
        Add a vbaProject binary and a vbaProjectSignature binary to the
        Excel workbook.

        Args:
            vba_project:           The vbaProject binary file name.
            signature:             The vbaProjectSignature binary file name.
            project_is_stream:     vba_project is an in memory byte stream.
            signature_is_stream:   signature is an in memory byte stream.

        Returns:
            Nothing.

        """
        if self.add_vba_project(vba_project, project_is_stream) == -1:
            return -1

        if not signature_is_stream and not os.path.exists(signature):
            warn("VBA project signature binary file '%s' not found." % signature)
            return -1

        self.vba_project_signature = signature
        self.vba_project_signature_is_stream = signature_is_stream

    def close(self):
        """
        Call finalization code and close file.

        Args:
            None.

        Returns:
            Nothing.

        """
        if not self.fileclosed:
            try:
                self._store_workbook()
            except IOError as e:
                raise FileCreateError(e)
            except LargeZipFile:
                raise FileSizeError(
                    "Filesize would require ZIP64 extensions. "
                    "Use workbook.use_zip64()."
                )

            self.fileclosed = True

            # Ensure all constant_memory temp files are closed.
            if self.constant_memory:
                for worksheet in self.worksheets():
                    worksheet._opt_close()

        else:
            warn("Calling close() on already closed file.")

    def set_size(self, width, height):
        """
        Set the size of a workbook window.

        Args:
            width:  Width  of the window in pixels.
            height: Height of the window in pixels.

        Returns:
            Nothing.

        """
        # Convert the width/height to twips at 96 dpi.
        if width:
            self.window_width = int(width * 1440 / 96)
        else:
            self.window_width = 16095

        if height:
            self.window_height = int(height * 1440 / 96)
        else:
            self.window_height = 9660

    def set_tab_ratio(self, tab_ratio=None):
        """
        Set the ratio between worksheet tabs and the horizontal slider.

        Args:
            tab_ratio: The tab ratio, 0 <= tab_ratio <= 100

        Returns:
            Nothing.

        """
        if tab_ratio is None:
            return

        if tab_ratio < 0 or tab_ratio > 100:
            warn("Tab ratio '%d' outside: 0 <= tab_ratio <= 100" % tab_ratio)
        else:
            self.tab_ratio = int(tab_ratio * 10)

    def set_properties(self, properties):
        """
        Set the document properties such as Title, Author etc.

        Args:
            properties: Dictionary of document properties.

        Returns:
            Nothing.

        """
        self.doc_properties = properties

    def set_custom_property(self, name, value, property_type=None):
        """
        Set a custom document property.

        Args:
            name:          The name of the custom property.
            value:         The value of the custom property.
            property_type: The type of the custom property. Optional.

        Returns:
            Nothing.

        """
        if name is None or value is None:
            warn(
                "The name and value parameters must be non-None in "
                "set_custom_property()"
            )
            return -1

        if property_type is None:
            # Determine the property type from the Python type.
            if isinstance(value, bool):
                property_type = "bool"
            elif isinstance(value, datetime):
                property_type = "date"
            elif isinstance(value, int):
                property_type = "number_int"
            elif isinstance(value, (float, int, Decimal, Fraction)):
                property_type = "number"
            else:
                property_type = "text"

        if property_type == "date":
            value = value.strftime("%Y-%m-%dT%H:%M:%SZ")

        if property_type == "text" and len(value) > 255:
            warn(
                "Length of 'value' parameter exceeds Excel's limit of 255 "
                "characters in set_custom_property(): '%s'" % value
            )

        if len(name) > 255:
            warn(
                "Length of 'name' parameter exceeds Excel's limit of 255 "
                "characters in set_custom_property(): '%s'" % name
            )

        self.custom_properties.append((name, value, property_type))

    def set_calc_mode(self, mode, calc_id=None):
        """
        Set the Excel calculation mode for the workbook.

        Args:
            mode: String containing one of:
                * manual
                * auto_except_tables
                * auto

        Returns:
            Nothing.

        """
        self.calc_mode = mode

        if mode == "manual":
            self.calc_on_load = False
        elif mode == "auto_except_tables":
            self.calc_mode = "autoNoTable"

        # Leave undocumented for now. Rarely required.
        if calc_id:
            self.calc_id = calc_id

    def define_name(self, name, formula):
        # Create a defined name in Excel. We handle global/workbook level
        # names and local/worksheet names.
        """
        Create a defined name in the workbook.

        Args:
            name:    The defined name.
            formula: The cell or range that the defined name refers to.

        Returns:
            Nothing.

        """
        sheet_index = None
        sheetname = ""

        # Remove the = sign from the formula if it exists.
        if formula.startswith("="):
            formula = formula.lstrip("=")

        # Local defined names are formatted like "Sheet1!name".
        sheet_parts = re.compile(r"^([^!]+)!([^!]+)$")
        match = sheet_parts.match(name)

        if match:
            sheetname = match.group(1)
            name = match.group(2)
            sheet_index = self._get_sheet_index(sheetname)

            # Warn if the sheet index wasn't found.
            if sheet_index is None:
                warn("Unknown sheet name '%s' in defined_name()" % sheetname)
                return -1
        else:
            # Use -1 to indicate global names.
            sheet_index = -1

        # Warn if the defined name contains invalid chars as defined by Excel.
        if not re.match(r"^[\w\\][\w\\.]*$", name, re.UNICODE) or re.match(
            r"^\d", name
        ):
            warn("Invalid Excel characters in defined_name(): '%s'" % name)
            return -1

        # Warn if the defined name looks like a cell name.
        if re.match(r"^[a-zA-Z][a-zA-Z]?[a-dA-D]?\d+$", name):
            warn("Name looks like a cell name in defined_name(): '%s'" % name)
            return -1

        # Warn if the name looks like a R1C1 cell reference.
        if re.match(r"^[rcRC]$", name) or re.match(r"^[rcRC]\d+[rcRC]\d+$", name):
            warn("Invalid name '%s' like a RC cell ref in defined_name()" % name)
            return -1

        self.defined_names.append([name, sheet_index, formula, False])

    def worksheets(self):
        """
        Return a list of the worksheet objects in the workbook.

        Args:
            None.

        Returns:
            A list of worksheet objects.

        """
        return self.worksheets_objs

    def get_worksheet_by_name(self, name):
        """
        Return a worksheet object in the workbook using the sheetname.

        Args:
            name: The name of the worksheet.

        Returns:
            A worksheet object or None.

        """
        return self.sheetnames.get(name)

    def get_default_url_format(self):
        """
        Get the default url format used when a user defined format isn't
        specified with write_url(). The format is the hyperlink style defined
        by Excel for the default theme.

        Args:
            None.

        Returns:
            A format object.

        """
        return self.default_url_format

    def use_zip64(self):
        """
        Allow ZIP64 extensions when writing xlsx file zip container.

        Args:
            None.

        Returns:
            Nothing.

        """
        self.allow_zip64 = True

    def set_vba_name(self, name=None):
        """
        Set the VBA name for the workbook. By default the workbook is referred
        to as ThisWorkbook in VBA.

        Args:
            name: The VBA name for the workbook.

        Returns:
            Nothing.

        """
        if name is not None:
            self.vba_codename = name
        else:
            self.vba_codename = "ThisWorkbook"

    def read_only_recommended(self):
        """
        Set the Excel "Read-only recommended" option when saving a file.

        Args:
            None.

        Returns:
            Nothing.

        """
        self.read_only = 2

    ###########################################################################
    #
    # Private API.
    #
    ###########################################################################

    def _assemble_xml_file(self):
        # Assemble and write the XML file.

        # Prepare format object for passing to Style.pm.
        self._prepare_format_properties()

        # Write the XML declaration.
        self._xml_declaration()

        # Write the workbook element.
        self._write_workbook()

        # Write the fileVersion element.
        self._write_file_version()

        # Write the fileSharing element.
        self._write_file_sharing()

        # Write the workbookPr element.
        self._write_workbook_pr()

        # Write the bookViews element.
        self._write_book_views()

        # Write the sheets element.
        self._write_sheets()

        # Write the workbook defined names.
        self._write_defined_names()

        # Write the calcPr element.
        self._write_calc_pr()

        # Close the workbook tag.
        self._xml_end_tag("workbook")

        # Close the file.
        self._xml_close()

    def _store_workbook(self):
        # Create the xlsx/zip file.
        try:
            xlsx_file = ZipFile(
                self.filename,
                "w",
                compression=ZIP_DEFLATED,
                allowZip64=self.allow_zip64,
            )
        except IOError as e:
            raise e

        # Assemble worksheets into a workbook.
        packager = self._get_packager()

        # Add a default worksheet if non have been added.
        if not self.worksheets():
            self.add_worksheet()

        # Ensure that at least one worksheet has been selected.
        if self.worksheet_meta.activesheet == 0:
            self.worksheets_objs[0].selected = 1
            self.worksheets_objs[0].hidden = 0

        # Set the active sheet.
        for sheet in self.worksheets():
            if sheet.index == self.worksheet_meta.activesheet:
                sheet.active = 1

        # Set the sheet vba_codename the workbook has a vbaProject binary.
        if self.vba_project:
            for sheet in self.worksheets():
                if sheet.vba_codename is None:
                    sheet.set_vba_name()

        # Convert the SST strings data structure.
        self._prepare_sst_string_data()

        # Prepare the worksheet VML elements such as comments and buttons.
        self._prepare_vml()

        # Set the defined names for the worksheets such as Print Titles.
        self._prepare_defined_names()

        # Prepare the drawings, charts and images.
        self._prepare_drawings()

        # Add cached data to charts.
        self._add_chart_data()

        # Prepare the worksheet tables.
        self._prepare_tables()

        # Prepare the metadata file links.
        self._prepare_metadata()

        # Package the workbook.
        packager._add_workbook(self)
        packager._set_tmpdir(self.tmpdir)
        packager._set_in_memory(self.in_memory)
        xml_files = packager._create_package()

        # Free up the Packager object.
        packager = None

        # Add XML sub-files to the Zip file with their Excel filename.
        for file_id, file_data in enumerate(xml_files):
            os_filename, xml_filename, is_binary = file_data

            if self.in_memory:
                # Set sub-file timestamp to Excel's timestamp of 1/1/1980.
                zipinfo = ZipInfo(xml_filename, (1980, 1, 1, 0, 0, 0))

                # Copy compression type from parent ZipFile.
                zipinfo.compress_type = xlsx_file.compression

                if is_binary:
                    xlsx_file.writestr(zipinfo, os_filename.getvalue())
                else:
                    xlsx_file.writestr(zipinfo, os_filename.getvalue().encode("utf-8"))
            else:
                # The sub-files are tempfiles on disk, i.e, not in memory.

                # Set sub-file timestamp to 31/1/1980 due to portability
                # issues setting it to Excel's timestamp of 1/1/1980.
                timestamp = time.mktime((1980, 1, 31, 0, 0, 0, 0, 0, -1))
                os.utime(os_filename, (timestamp, timestamp))

                try:
                    xlsx_file.write(os_filename, xml_filename)
                    os.remove(os_filename)
                except LargeZipFile as e:
                    # Close open temp files on zipfile.LargeZipFile exception.
                    for i in range(file_id, len(xml_files) - 1):
                        os.remove(xml_files[i][0])
                    raise e

        xlsx_file.close()

    def _add_sheet(self, name, worksheet_class=None):
        # Utility for shared code in add_worksheet() and add_chartsheet().

        if worksheet_class:
            worksheet = worksheet_class()
        else:
            worksheet = self.worksheet_class()

        sheet_index = len(self.worksheets_objs)
        name = self._check_sheetname(name, isinstance(worksheet, Chartsheet))

        # Initialization data to pass to the worksheet.
        init_data = {
            "name": name,
            "index": sheet_index,
            "str_table": self.str_table,
            "worksheet_meta": self.worksheet_meta,
            "constant_memory": self.constant_memory,
            "tmpdir": self.tmpdir,
            "date_1904": self.date_1904,
            "strings_to_numbers": self.strings_to_numbers,
            "strings_to_formulas": self.strings_to_formulas,
            "strings_to_urls": self.strings_to_urls,
            "nan_inf_to_errors": self.nan_inf_to_errors,
            "default_date_format": self.default_date_format,
            "default_url_format": self.default_url_format,
            "excel2003_style": self.excel2003_style,
            "remove_timezone": self.remove_timezone,
            "max_url_length": self.max_url_length,
            "use_future_functions": self.use_future_functions,
        }

        worksheet._initialize(init_data)

        self.worksheets_objs.append(worksheet)
        self.sheetnames[name] = worksheet

        return worksheet

    def _check_sheetname(self, sheetname, is_chartsheet=False):
        # Check for valid worksheet names. We check the length, if it contains
        # any invalid chars and if the sheetname is unique in the workbook.
        invalid_char = re.compile(r"[\[\]:*?/\\]")

        # Increment the Sheet/Chart number used for default sheet names below.
        if is_chartsheet:
            self.chartname_count += 1
        else:
            self.sheetname_count += 1

        # Supply default Sheet/Chart sheetname if none has been defined.
        if sheetname is None or sheetname == "":
            if is_chartsheet:
                sheetname = self.chart_name + str(self.chartname_count)
            else:
                sheetname = self.sheet_name + str(self.sheetname_count)

        # Check that sheet sheetname is <= 31. Excel limit.
        if len(sheetname) > 31:
            raise InvalidWorksheetName(
                "Excel worksheet name '%s' must be <= 31 chars." % sheetname
            )

        # Check that sheetname doesn't contain any invalid characters.
        if invalid_char.search(sheetname):
            raise InvalidWorksheetName(
                "Invalid Excel character '[]:*?/\\' in sheetname '%s'." % sheetname
            )

        # Check that sheetname doesn't start or end with an apostrophe.
        if sheetname.startswith("'") or sheetname.endswith("'"):
            raise InvalidWorksheetName(
                'Sheet name cannot start or end with an apostrophe "%s".' % sheetname
            )

        # Check that the worksheet name doesn't already exist since this is a
        # fatal Excel error. The check must be case insensitive like Excel.
        for worksheet in self.worksheets():
            if sheetname.lower() == worksheet.name.lower():
                raise DuplicateWorksheetName(
                    "Sheetname '%s', with case ignored, is already in use." % sheetname
                )

        return sheetname

    def _prepare_format_properties(self):
        # Prepare all Format properties prior to passing them to styles.py.

        # Separate format objects into XF and DXF formats.
        self._prepare_formats()

        # Set the font index for the format objects.
        self._prepare_fonts()

        # Set the number format index for the format objects.
        self._prepare_num_formats()

        # Set the border index for the format objects.
        self._prepare_borders()

        # Set the fill index for the format objects.
        self._prepare_fills()

    def _prepare_formats(self):
        # Iterate through the XF Format objects and separate them into
        # XF and DXF formats. The XF and DF formats then need to be sorted
        # back into index order rather than creation order.
        xf_formats = []
        dxf_formats = []

        # Sort into XF and DXF formats.
        for xf_format in self.formats:
            if xf_format.xf_index is not None:
                xf_formats.append(xf_format)

            if xf_format.dxf_index is not None:
                dxf_formats.append(xf_format)

        # Pre-extend the format lists.
        self.xf_formats = [None] * len(xf_formats)
        self.dxf_formats = [None] * len(dxf_formats)

        # Rearrange formats into index order.
        for xf_format in xf_formats:
            index = xf_format.xf_index
            self.xf_formats[index] = xf_format

        for dxf_format in dxf_formats:
            index = dxf_format.dxf_index
            self.dxf_formats[index] = dxf_format

    def _set_default_xf_indices(self):
        # Set the default index for each format. Only used for testing.

        formats = list(self.formats)

        # Delete the default url format.
        del formats[1]

        # Skip the default date format if set.
        if self.default_date_format is not None:
            del formats[1]

        # Set the remaining formats.
        for xf_format in formats:
            xf_format._get_xf_index()

    def _prepare_fonts(self):
        # Iterate through the XF Format objects and give them an index to
        # non-default font elements.
        fonts = {}
        index = 0

        for xf_format in self.xf_formats:
            key = xf_format._get_font_key()
            if key in fonts:
                # Font has already been used.
                xf_format.font_index = fonts[key]
                xf_format.has_font = 0
            else:
                # This is a new font.
                fonts[key] = index
                xf_format.font_index = index
                xf_format.has_font = 1
                index += 1

        self.font_count = index

        # For DXF formats we only need to check if the properties have changed.
        for xf_format in self.dxf_formats:
            # The only font properties that can change for a DXF format are:
            # color, bold, italic, underline and strikethrough.
            if (
                xf_format.font_color
                or xf_format.bold
                or xf_format.italic
                or xf_format.underline
                or xf_format.font_strikeout
            ):
                xf_format.has_dxf_font = 1

    def _prepare_num_formats(self):
        # User defined records in Excel start from index 0xA4.
        unique_num_formats = {}
        num_formats = []
        index = 164

        for xf_format in self.xf_formats + self.dxf_formats:
            num_format = xf_format.num_format

            # Check if num_format is an index to a built-in number format.
            if not isinstance(num_format, str):
                num_format = int(num_format)

                # Number format '0' is indexed as 1 in Excel.
                if num_format == 0:
                    num_format = 1

                xf_format.num_format_index = num_format
                continue
            elif num_format == "0":
                # Number format '0' is indexed as 1 in Excel.
                xf_format.num_format_index = 1
                continue
            elif num_format == "General":
                # The 'General' format has an number format index of 0.
                xf_format.num_format_index = 0
                continue

            if num_format in unique_num_formats:
                # Number xf_format has already been used.
                xf_format.num_format_index = unique_num_formats[num_format]
            else:
                # Add a new number xf_format.
                unique_num_formats[num_format] = index
                xf_format.num_format_index = index
                index += 1

                # Only increase font count for XF formats (not DXF formats).
                if xf_format.xf_index:
                    num_formats.append(num_format)

        self.num_formats = num_formats

    def _prepare_borders(self):
        # Iterate through the XF Format objects and give them an index to
        # non-default border elements.
        borders = {}
        index = 0

        for xf_format in self.xf_formats:
            key = xf_format._get_border_key()

            if key in borders:
                # Border has already been used.
                xf_format.border_index = borders[key]
                xf_format.has_border = 0
            else:
                # This is a new border.
                borders[key] = index
                xf_format.border_index = index
                xf_format.has_border = 1
                index += 1

        self.border_count = index

        # For DXF formats we only need to check if the properties have changed.
        has_border = re.compile(r"[^0:]")

        for xf_format in self.dxf_formats:
            key = xf_format._get_border_key()

            if has_border.search(key):
                xf_format.has_dxf_border = 1

    def _prepare_fills(self):
        # Iterate through the XF Format objects and give them an index to
        # non-default fill elements.
        # The user defined fill properties start from 2 since there are 2
        # default fills: patternType="none" and patternType="gray125".
        fills = {}
        index = 2  # Start from 2. See above.

        # Add the default fills.
        fills["0:0:0"] = 0
        fills["17:0:0"] = 1

        # Store the DXF colors separately since them may be reversed below.
        for xf_format in self.dxf_formats:
            if xf_format.pattern or xf_format.bg_color or xf_format.fg_color:
                xf_format.has_dxf_fill = 1
                xf_format.dxf_bg_color = xf_format.bg_color
                xf_format.dxf_fg_color = xf_format.fg_color

        for xf_format in self.xf_formats:
            # The following logical statements jointly take care of special
            # cases in relation to cell colors and patterns:
            # 1. For a solid fill (_pattern == 1) Excel reverses the role of
            # foreground and background colors, and
            # 2. If the user specifies a foreground or background color
            # without a pattern they probably wanted a solid fill, so we fill
            # in the defaults.
            if (
                xf_format.pattern == 1
                and xf_format.bg_color != 0
                and xf_format.fg_color != 0
            ):
                tmp = xf_format.fg_color
                xf_format.fg_color = xf_format.bg_color
                xf_format.bg_color = tmp

            if (
                xf_format.pattern <= 1
                and xf_format.bg_color != 0
                and xf_format.fg_color == 0
            ):
                xf_format.fg_color = xf_format.bg_color
                xf_format.bg_color = 0
                xf_format.pattern = 1

            if (
                xf_format.pattern <= 1
                and xf_format.bg_color == 0
                and xf_format.fg_color != 0
            ):
                xf_format.pattern = 1

            key = xf_format._get_fill_key()

            if key in fills:
                # Fill has already been used.
                xf_format.fill_index = fills[key]
                xf_format.has_fill = 0
            else:
                # This is a new fill.
                fills[key] = index
                xf_format.fill_index = index
                xf_format.has_fill = 1
                index += 1

        self.fill_count = index

    def _prepare_defined_names(self):
        # Iterate through the worksheets and store any defined names in
        # addition to any user defined names. Stores the defined names
        # for the Workbook.xml and the named ranges for App.xml.
        defined_names = self.defined_names

        for sheet in self.worksheets():
            # Check for Print Area settings.
            if sheet.autofilter_area:
                hidden = 1
                sheet_range = sheet.autofilter_area
                # Store the defined names.
                defined_names.append(
                    ["_xlnm._FilterDatabase", sheet.index, sheet_range, hidden]
                )

            # Check for Print Area settings.
            if sheet.print_area_range:
                hidden = 0
                sheet_range = sheet.print_area_range
                # Store the defined names.
                defined_names.append(
                    ["_xlnm.Print_Area", sheet.index, sheet_range, hidden]
                )

            # Check for repeat rows/cols referred to as Print Titles.
            if sheet.repeat_col_range or sheet.repeat_row_range:
                hidden = 0
                sheet_range = ""
                if sheet.repeat_col_range and sheet.repeat_row_range:
                    sheet_range = sheet.repeat_col_range + "," + sheet.repeat_row_range
                else:
                    sheet_range = sheet.repeat_col_range + sheet.repeat_row_range
                # Store the defined names.
                defined_names.append(
                    ["_xlnm.Print_Titles", sheet.index, sheet_range, hidden]
                )

        defined_names = self._sort_defined_names(defined_names)
        self.defined_names = defined_names
        self.named_ranges = self._extract_named_ranges(defined_names)

    def _sort_defined_names(self, names):
        # Sort the list of list of internal and user defined names in
        # the same order as used by Excel.

        # Add a normalize name string to each list for sorting.
        for name_list in names:
            (defined_name, _, sheet_name, _) = name_list

            # Normalize the defined name by removing any leading '_xmln.'
            # from internal names and lowercasing the string.
            defined_name = defined_name.replace("_xlnm.", "").lower()

            # Normalize the sheetname by removing the leading quote and
            # lowercasing the string.
            sheet_name = sheet_name.lstrip("'").lower()

            name_list.append(defined_name + "::" + sheet_name)

        # Sort based on the normalized key.
        names.sort(key=operator.itemgetter(4))

        # Remove the extra key used for sorting.
        for name_list in names:
            name_list.pop()

        return names

    def _prepare_drawings(self):
        # Iterate through the worksheets and set up chart and image drawings.
        chart_ref_id = 0
        image_ref_id = 0
        ref_id = 0
        drawing_id = 0
        image_ids = {}
        header_image_ids = {}
        background_ids = {}

        for sheet in self.worksheets():
            chart_count = len(sheet.charts)
            image_count = len(sheet.images)
            shape_count = len(sheet.shapes)

            header_image_count = len(sheet.header_images)
            footer_image_count = len(sheet.footer_images)
            has_background = sheet.background_image
            has_drawing = False

            if not (
                chart_count
                or image_count
                or shape_count
                or header_image_count
                or footer_image_count
                or has_background
            ):
                continue

            # Don't increase the drawing_id header/footer images.
            if chart_count or image_count or shape_count:
                drawing_id += 1
                has_drawing = True

            # Prepare the background images.
            if sheet.background_image:
                if sheet.background_bytes:
                    filename = ""
                    image_data = sheet.background_image
                else:
                    filename = sheet.background_image
                    image_data = None

                (
                    image_type,
                    _,
                    _,
                    _,
                    _,
                    _,
                    digest,
                ) = self._get_image_properties(filename, image_data)

                if digest in background_ids:
                    ref_id = background_ids[digest]
                else:
                    image_ref_id += 1
                    ref_id = image_ref_id
                    background_ids[digest] = image_ref_id
                    self.images.append([filename, image_type, image_data])

                sheet._prepare_background(ref_id, image_type)

            # Prepare the worksheet images.
            for index in range(image_count):
                filename = sheet.images[index][2]
                image_data = sheet.images[index][10]
                (
                    image_type,
                    width,
                    height,
                    name,
                    x_dpi,
                    y_dpi,
                    digest,
                ) = self._get_image_properties(filename, image_data)

                if digest in image_ids:
                    ref_id = image_ids[digest]
                else:
                    image_ref_id += 1
                    ref_id = image_ref_id
                    image_ids[digest] = image_ref_id
                    self.images.append([filename, image_type, image_data])

                sheet._prepare_image(
                    index,
                    ref_id,
                    drawing_id,
                    width,
                    height,
                    name,
                    image_type,
                    x_dpi,
                    y_dpi,
                    digest,
                )

            # Prepare the worksheet charts.
            for index in range(chart_count):
                chart_ref_id += 1
                sheet._prepare_chart(index, chart_ref_id, drawing_id)

            # Prepare the worksheet shapes.
            for index in range(shape_count):
                sheet._prepare_shape(index, drawing_id)

            # Prepare the header images.
            for index in range(header_image_count):
                filename = sheet.header_images[index][0]
                image_data = sheet.header_images[index][1]
                position = sheet.header_images[index][2]

                (
                    image_type,
                    width,
                    height,
                    name,
                    x_dpi,
                    y_dpi,
                    digest,
                ) = self._get_image_properties(filename, image_data)

                if digest in header_image_ids:
                    ref_id = header_image_ids[digest]
                else:
                    image_ref_id += 1
                    ref_id = image_ref_id
                    header_image_ids[digest] = image_ref_id
                    self.images.append([filename, image_type, image_data])

                sheet._prepare_header_image(
                    ref_id,
                    width,
                    height,
                    name,
                    image_type,
                    position,
                    x_dpi,
                    y_dpi,
                    digest,
                )

            # Prepare the footer images.
            for index in range(footer_image_count):
                filename = sheet.footer_images[index][0]
                image_data = sheet.footer_images[index][1]
                position = sheet.footer_images[index][2]

                (
                    image_type,
                    width,
                    height,
                    name,
                    x_dpi,
                    y_dpi,
                    digest,
                ) = self._get_image_properties(filename, image_data)

                if digest in header_image_ids:
                    ref_id = header_image_ids[digest]
                else:
                    image_ref_id += 1
                    ref_id = image_ref_id
                    header_image_ids[digest] = image_ref_id
                    self.images.append([filename, image_type, image_data])

                sheet._prepare_header_image(
                    ref_id,
                    width,
                    height,
                    name,
                    image_type,
                    position,
                    x_dpi,
                    y_dpi,
                    digest,
                )

            if has_drawing:
                drawing = sheet.drawing
                self.drawings.append(drawing)

        # Remove charts that were created but not inserted into worksheets.
        for chart in self.charts[:]:
            if chart.id == -1:
                self.charts.remove(chart)

        # Sort the workbook charts references into the order that the were
        # written to the worksheets above.
        self.charts = sorted(self.charts, key=lambda chart: chart.id)

        self.drawing_count = drawing_id

    def _get_image_properties(self, filename, image_data):
        # Extract dimension information from the image file.
        height = 0
        width = 0
        x_dpi = 96
        y_dpi = 96

        if not image_data:
            # Open the image file and read in the data.
            fh = open(filename, "rb")
            data = fh.read()
        else:
            # Read the image data from the user supplied byte stream.
            data = image_data.getvalue()

        digest = hashlib.sha256(data).hexdigest()

        # Get the image filename without the path.
        image_name = os.path.basename(filename)

        # Look for some common image file markers.
        marker1 = unpack("3s", data[1:4])[0]
        marker2 = unpack(">H", data[:2])[0]
        marker3 = unpack("2s", data[:2])[0]
        marker4 = unpack("<L", data[:4])[0]
        marker5 = (unpack("4s", data[40:44]))[0]
        marker6 = unpack("4s", data[:4])[0]

        png_marker = b"PNG"
        bmp_marker = b"BM"
        emf_marker = b" EMF"
        gif_marker = b"GIF8"

        if marker1 == png_marker:
            self.image_types["png"] = True
            (image_type, width, height, x_dpi, y_dpi) = self._process_png(data)

        elif marker2 == 0xFFD8:
            self.image_types["jpeg"] = True
            (image_type, width, height, x_dpi, y_dpi) = self._process_jpg(data)

        elif marker3 == bmp_marker:
            self.image_types["bmp"] = True
            (image_type, width, height) = self._process_bmp(data)

        elif marker4 == 0x9AC6CDD7:
            self.image_types["wmf"] = True
            (image_type, width, height, x_dpi, y_dpi) = self._process_wmf(data)

        elif marker4 == 1 and marker5 == emf_marker:
            self.image_types["emf"] = True
            (image_type, width, height, x_dpi, y_dpi) = self._process_emf(data)

        elif marker6 == gif_marker:
            self.image_types["gif"] = True
            (image_type, width, height, x_dpi, y_dpi) = self._process_gif(data)

        else:
            raise UnsupportedImageFormat(
                "%s: Unknown or unsupported image file format." % filename
            )

        # Check that we found the required data.
        if not height or not width:
            raise UndefinedImageSize("%s: no size data found in image file." % filename)

        if not image_data:
            fh.close()

        # Set a default dpi for images with 0 dpi.
        if x_dpi == 0:
            x_dpi = 96
        if y_dpi == 0:
            y_dpi = 96

        return image_type, width, height, image_name, x_dpi, y_dpi, digest

    def _process_png(self, data):
        # Extract width and height information from a PNG file.
        offset = 8
        data_length = len(data)
        end_marker = False
        width = 0
        height = 0
        x_dpi = 96
        y_dpi = 96

        # Search through the image data to read the height and width in the
        # IHDR element. Also read the DPI in the pHYs element.
        while not end_marker and offset < data_length:
            length = unpack(">I", data[offset + 0 : offset + 4])[0]
            marker = unpack("4s", data[offset + 4 : offset + 8])[0]

            # Read the image dimensions.
            if marker == b"IHDR":
                width = unpack(">I", data[offset + 8 : offset + 12])[0]
                height = unpack(">I", data[offset + 12 : offset + 16])[0]

            # Read the image DPI.
            if marker == b"pHYs":
                x_density = unpack(">I", data[offset + 8 : offset + 12])[0]
                y_density = unpack(">I", data[offset + 12 : offset + 16])[0]
                units = unpack("b", data[offset + 16 : offset + 17])[0]

                if units == 1:
                    x_dpi = x_density * 0.0254
                    y_dpi = y_density * 0.0254

            if marker == b"IEND":
                end_marker = True
                continue

            offset = offset + length + 12

        return "png", width, height, x_dpi, y_dpi

    def _process_jpg(self, data):
        # Extract width and height information from a JPEG file.
        offset = 2
        data_length = len(data)
        end_marker = False
        width = 0
        height = 0
        x_dpi = 96
        y_dpi = 96

        # Search through the image data to read the JPEG markers.
        while not end_marker and offset < data_length:
            marker = unpack(">H", data[offset + 0 : offset + 2])[0]
            length = unpack(">H", data[offset + 2 : offset + 4])[0]

            # Read the height and width in the 0xFFCn elements (except C4, C8
            # and CC which aren't SOF markers).
            if (
                (marker & 0xFFF0) == 0xFFC0
                and marker != 0xFFC4
                and marker != 0xFFC8
                and marker != 0xFFCC
            ):
                height = unpack(">H", data[offset + 5 : offset + 7])[0]
                width = unpack(">H", data[offset + 7 : offset + 9])[0]

            # Read the DPI in the 0xFFE0 element.
            if marker == 0xFFE0:
                units = unpack("b", data[offset + 11 : offset + 12])[0]
                x_density = unpack(">H", data[offset + 12 : offset + 14])[0]
                y_density = unpack(">H", data[offset + 14 : offset + 16])[0]

                if units == 1:
                    x_dpi = x_density
                    y_dpi = y_density

                if units == 2:
                    x_dpi = x_density * 2.54
                    y_dpi = y_density * 2.54

                # Workaround for incorrect dpi.
                if x_dpi == 1:
                    x_dpi = 96
                if y_dpi == 1:
                    y_dpi = 96

            if marker == 0xFFDA:
                end_marker = True
                continue

            offset = offset + length + 2

        return "jpeg", width, height, x_dpi, y_dpi

    def _process_gif(self, data):
        # Extract width and height information from a GIF file.
        x_dpi = 96
        y_dpi = 96

        width = unpack("<h", data[6:8])[0]
        height = unpack("<h", data[8:10])[0]

        return "gif", width, height, x_dpi, y_dpi

    def _process_bmp(self, data):
        # Extract width and height information from a BMP file.
        width = unpack("<L", data[18:22])[0]
        height = unpack("<L", data[22:26])[0]
        return "bmp", width, height

    def _process_wmf(self, data):
        # Extract width and height information from a WMF file.
        x_dpi = 96
        y_dpi = 96

        # Read the bounding box, measured in logical units.
        x1 = unpack("<h", data[6:8])[0]
        y1 = unpack("<h", data[8:10])[0]
        x2 = unpack("<h", data[10:12])[0]
        y2 = unpack("<h", data[12:14])[0]

        # Read the number of logical units per inch. Used to scale the image.
        inch = unpack("<H", data[14:16])[0]

        # Convert to rendered height and width.
        width = float((x2 - x1) * x_dpi) / inch
        height = float((y2 - y1) * y_dpi) / inch

        return "wmf", width, height, x_dpi, y_dpi

    def _process_emf(self, data):
        # Extract width and height information from a EMF file.

        # Read the bounding box, measured in logical units.
        bound_x1 = unpack("<l", data[8:12])[0]
        bound_y1 = unpack("<l", data[12:16])[0]
        bound_x2 = unpack("<l", data[16:20])[0]
        bound_y2 = unpack("<l", data[20:24])[0]

        # Convert the bounds to width and height.
        width = bound_x2 - bound_x1
        height = bound_y2 - bound_y1

        # Read the rectangular frame in units of 0.01mm.
        frame_x1 = unpack("<l", data[24:28])[0]
        frame_y1 = unpack("<l", data[28:32])[0]
        frame_x2 = unpack("<l", data[32:36])[0]
        frame_y2 = unpack("<l", data[36:40])[0]

        # Convert the frame bounds to mm width and height.
        width_mm = 0.01 * (frame_x2 - frame_x1)
        height_mm = 0.01 * (frame_y2 - frame_y1)

        # Get the dpi based on the logical size.
        x_dpi = width * 25.4 / width_mm
        y_dpi = height * 25.4 / height_mm

        # This is to match Excel's calculation. It is probably to account for
        # the fact that the bounding box is inclusive-inclusive. Or a bug.
        width += 1
        height += 1

        return "emf", width, height, x_dpi, y_dpi

    def _extract_named_ranges(self, defined_names):
        # Extract the named ranges from the sorted list of defined names.
        # These are used in the App.xml file.
        named_ranges = []

        for defined_name in defined_names:
            name = defined_name[0]
            index = defined_name[1]
            sheet_range = defined_name[2]

            # Skip autoFilter ranges.
            if name == "_xlnm._FilterDatabase":
                continue

            # We are only interested in defined names with ranges.
            if "!" in sheet_range:
                sheet_name, _ = sheet_range.split("!", 1)

                # Match Print_Area and Print_Titles xlnm types.
                if name.startswith("_xlnm."):
                    xlnm_type = name.replace("_xlnm.", "")
                    name = sheet_name + "!" + xlnm_type
                elif index != -1:
                    name = sheet_name + "!" + name

                named_ranges.append(name)

        return named_ranges

    def _get_sheet_index(self, sheetname):
        # Convert a sheet name to its index. Return None otherwise.
        sheetname = sheetname.strip("'")

        if sheetname in self.sheetnames:
            return self.sheetnames[sheetname].index
        else:
            return None

    def _prepare_vml(self):
        # Iterate through the worksheets and set up the VML objects.
        comment_id = 0
        vml_drawing_id = 0
        vml_data_id = 1
        vml_header_id = 0
        vml_shape_id = 1024
        vml_files = 0
        comment_files = 0

        for sheet in self.worksheets():
            if not sheet.has_vml and not sheet.has_header_vml:
                continue

            vml_files += 1

            if sheet.has_vml:
                if sheet.has_comments:
                    comment_files += 1
                    comment_id += 1
                    self.has_comments = True

                vml_drawing_id += 1

                count = sheet._prepare_vml_objects(
                    vml_data_id, vml_shape_id, vml_drawing_id, comment_id
                )

                # Each VML should start with a shape id incremented by 1024.
                vml_data_id += 1 * int((1024 + count) / 1024)
                vml_shape_id += 1024 * int((1024 + count) / 1024)

            if sheet.has_header_vml:
                vml_header_id += 1
                vml_drawing_id += 1
                sheet._prepare_header_vml_objects(vml_header_id, vml_drawing_id)

            self.num_vml_files = vml_files
            self.num_comment_files = comment_files

    def _prepare_tables(self):
        # Set the table ids for the worksheet tables.
        table_id = 0
        seen = {}

        for sheet in self.worksheets():
            table_count = len(sheet.tables)

            if not table_count:
                continue

            sheet._prepare_tables(table_id + 1, seen)
            table_id += table_count

    def _prepare_metadata(self):
        # Set the metadata rel link.
        for sheet in self.worksheets():
            if sheet.has_dynamic_arrays:
                self.has_metadata = True

    def _add_chart_data(self):
        # Add "cached" data to charts to provide the numCache and strCache
        # data for series and title/axis ranges.
        worksheets = {}
        seen_ranges = {}
        charts = []

        # Map worksheet names to worksheet objects.
        for worksheet in self.worksheets():
            worksheets[worksheet.name] = worksheet

        # Build a list of the worksheet charts including any combined charts.
        for chart in self.charts:
            charts.append(chart)
            if chart.combined:
                charts.append(chart.combined)

        for chart in charts:
            for c_range in chart.formula_ids.keys():
                r_id = chart.formula_ids[c_range]

                # Skip if the series has user defined data.
                if chart.formula_data[r_id] is not None:
                    if c_range not in seen_ranges or seen_ranges[c_range] is None:
                        data = chart.formula_data[r_id]
                        seen_ranges[c_range] = data
                    continue

                # Check to see if the data is already cached locally.
                if c_range in seen_ranges:
                    chart.formula_data[r_id] = seen_ranges[c_range]
                    continue

                # Convert the range formula to a sheet name and cell range.
                (sheetname, cells) = self._get_chart_range(c_range)

                # Skip if we couldn't parse the formula.
                if sheetname is None:
                    continue

                # Handle non-contiguous ranges like:
                #     (Sheet1!$A$1:$A$2,Sheet1!$A$4:$A$5).
                # We don't try to parse them. We just return an empty list.
                if sheetname.startswith("("):
                    chart.formula_data[r_id] = []
                    seen_ranges[c_range] = []
                    continue

                # Warn if the name is unknown since it indicates a user error
                # in a chart series formula.
                if sheetname not in worksheets:
                    warn(
                        "Unknown worksheet reference '%s' in range "
                        "'%s' passed to add_series()" % (sheetname, c_range)
                    )
                    chart.formula_data[r_id] = []
                    seen_ranges[c_range] = []
                    continue

                # Find the worksheet object based on the sheet name.
                worksheet = worksheets[sheetname]

                # Get the data from the worksheet table.
                data = worksheet._get_range_data(*cells)

                # Add the data to the chart.
                chart.formula_data[r_id] = data

                # Store range data locally to avoid lookup if seen again.
                seen_ranges[c_range] = data

    def _get_chart_range(self, c_range):
        # Convert a range formula such as Sheet1!$B$1:$B$5 into a sheet name
        # and cell range such as ( 'Sheet1', 0, 1, 4, 1 ).

        # Split the range formula into sheetname and cells at the last '!'.
        pos = c_range.rfind("!")
        if pos > 0:
            sheetname = c_range[:pos]
            cells = c_range[pos + 1 :]
        else:
            return None, None

        # Split the cell range into 2 cells or else use single cell for both.
        if cells.find(":") > 0:
            (cell_1, cell_2) = cells.split(":", 1)
        else:
            (cell_1, cell_2) = (cells, cells)

        # Remove leading/trailing quotes and convert escaped quotes to single.
        sheetname = sheetname.strip("'")
        sheetname = sheetname.replace("''", "'")

        try:
            # Get the row, col values from the Excel ranges. We do this in a
            # try block for ranges that can't be parsed such as defined names.
            (row_start, col_start) = xl_cell_to_rowcol(cell_1)
            (row_end, col_end) = xl_cell_to_rowcol(cell_2)
        except AttributeError:
            return None, None

        # We only handle 1D ranges.
        if row_start != row_end and col_start != col_end:
            return None, None

        return sheetname, [row_start, col_start, row_end, col_end]

    def _prepare_sst_string_data(self):
        # Convert the SST string data from a dict to a list.
        self.str_table._sort_string_data()

    def _get_packager(self):
        # Get and instance of the Packager class to create the xlsx package.
        # This allows the default packager to be over-ridden.
        return Packager()

    ###########################################################################
    #
    # XML methods.
    #
    ###########################################################################

    def _write_workbook(self):
        # Write <workbook> element.

        schema = "http://schemas.openxmlformats.org"
        xmlns = schema + "/spreadsheetml/2006/main"
        xmlns_r = schema + "/officeDocument/2006/relationships"

        attributes = [
            ("xmlns", xmlns),
            ("xmlns:r", xmlns_r),
        ]

        self._xml_start_tag("workbook", attributes)

    def _write_file_version(self):
        # Write the <fileVersion> element.

        app_name = "xl"
        last_edited = 4
        lowest_edited = 4
        rup_build = 4505

        attributes = [
            ("appName", app_name),
            ("lastEdited", last_edited),
            ("lowestEdited", lowest_edited),
            ("rupBuild", rup_build),
        ]

        if self.vba_project:
            attributes.append(("codeName", "{37E998C4-C9E5-D4B9-71C8-EB1FF731991C}"))

        self._xml_empty_tag("fileVersion", attributes)

    def _write_file_sharing(self):
        # Write the <fileSharing> element.
        if self.read_only == 0:
            return

        attributes = [("readOnlyRecommended", 1)]

        self._xml_empty_tag("fileSharing", attributes)

    def _write_workbook_pr(self):
        # Write <workbookPr> element.
        default_theme_version = 124226
        attributes = []

        if self.vba_codename:
            attributes.append(("codeName", self.vba_codename))
        if self.date_1904:
            attributes.append(("date1904", 1))

        attributes.append(("defaultThemeVersion", default_theme_version))

        self._xml_empty_tag("workbookPr", attributes)

    def _write_book_views(self):
        # Write <bookViews> element.
        self._xml_start_tag("bookViews")
        self._write_workbook_view()
        self._xml_end_tag("bookViews")

    def _write_workbook_view(self):
        # Write <workbookView> element.
        attributes = [
            ("xWindow", self.x_window),
            ("yWindow", self.y_window),
            ("windowWidth", self.window_width),
            ("windowHeight", self.window_height),
        ]

        # Store the tabRatio attribute when it isn't the default.
        if self.tab_ratio != 600:
            attributes.append(("tabRatio", self.tab_ratio))

        # Store the firstSheet attribute when it isn't the default.
        if self.worksheet_meta.firstsheet > 0:
            firstsheet = self.worksheet_meta.firstsheet + 1
            attributes.append(("firstSheet", firstsheet))

        # Store the activeTab attribute when it isn't the first sheet.
        if self.worksheet_meta.activesheet > 0:
            attributes.append(("activeTab", self.worksheet_meta.activesheet))

        self._xml_empty_tag("workbookView", attributes)

    def _write_sheets(self):
        # Write <sheets> element.
        self._xml_start_tag("sheets")

        id_num = 1
        for worksheet in self.worksheets():
            self._write_sheet(worksheet.name, id_num, worksheet.hidden)
            id_num += 1

        self._xml_end_tag("sheets")

    def _write_sheet(self, name, sheet_id, hidden):
        # Write <sheet> element.
        attributes = [
            ("name", name),
            ("sheetId", sheet_id),
        ]

        if hidden == 1:
            attributes.append(("state", "hidden"))
        elif hidden == 2:
            attributes.append(("state", "veryHidden"))

        attributes.append(("r:id", "rId" + str(sheet_id)))

        self._xml_empty_tag("sheet", attributes)

    def _write_calc_pr(self):
        # Write the <calcPr> element.
        attributes = [("calcId", self.calc_id)]

        if self.calc_mode == "manual":
            attributes.append(("calcMode", self.calc_mode))
            attributes.append(("calcOnSave", "0"))
        elif self.calc_mode == "autoNoTable":
            attributes.append(("calcMode", self.calc_mode))

        if self.calc_on_load:
            attributes.append(("fullCalcOnLoad", "1"))

        self._xml_empty_tag("calcPr", attributes)

    def _write_defined_names(self):
        # Write the <definedNames> element.
        if not self.defined_names:
            return

        self._xml_start_tag("definedNames")

        for defined_name in self.defined_names:
            self._write_defined_name(defined_name)

        self._xml_end_tag("definedNames")

    def _write_defined_name(self, defined_name):
        # Write the <definedName> element.
        name = defined_name[0]
        sheet_id = defined_name[1]
        sheet_range = defined_name[2]
        hidden = defined_name[3]

        attributes = [("name", name)]

        if sheet_id != -1:
            attributes.append(("localSheetId", sheet_id))
        if hidden:
            attributes.append(("hidden", 1))

        self._xml_data_element("definedName", sheet_range, attributes)


# A metadata class to share data between worksheets.
class WorksheetMeta(object):
    """
    A class to track worksheets data such as the active sheet and the
    first sheet.

    """

    def __init__(self):
        self.activesheet = 0
        self.firstsheet = 0
