# encoding: utf-8

"""
Directly exposed API functions and classes, :func:`Document` for now.
Provides a syntactically more convenient API for interacting with the
OpcPackage graph.
"""

from __future__ import absolute_import, division, print_function

import os

from docx.enum.section import WD_SECTION
from docx.enum.text import WD_BREAK
from docx.opc.constants import CONTENT_TYPE as CT, RELATIONSHIP_TYPE as RT
from docx.package import Package
from docx.parts.numbering import NumberingPart
from docx.parts.styles import StylesPart
from docx.shared import lazyproperty


_thisdir = os.path.split(__file__)[0]
_default_docx_path = os.path.join(_thisdir, 'templates', 'default.docx')


class Document(object):
    """
    Return a |Document| instance loaded from *docx*, where *docx* can be
    either a path to a ``.docx`` file (a string) or a file-like object. If
    *docx* is missing or ``None``, the built-in default document "template"
    is loaded.
    """
    def __init__(self, docx=None):
        super(Document, self).__init__()
        document_part, package = self._open(docx)
        self._document_part = document_part
        self._package = package

    def add_heading(self, text='', level=1):
        """
        Return a heading paragraph newly added to the end of the document,
        populated with *text* and having the heading paragraph style
        determined by *level*. If *level* is 0, the style is set to
        ``'Title'``. If *level* is 1 (or not present), ``'Heading1'`` is used.
        Otherwise the style is set to ``'Heading{level}'``. If *level* is
        outside the range 0-9, |ValueError| is raised.
        """
        if not 0 <= level <= 9:
            raise ValueError("level must be in range 0-9, got %d" % level)
        style = 'Title' if level == 0 else 'Heading%d' % level
        return self.add_paragraph(text, style)

    def add_page_break(self):
        """
        Return a paragraph newly added to the end of the document and
        containing only a page break.
        """
        p = self._document_part.add_paragraph()
        r = p.add_run()
        r.add_break(WD_BREAK.PAGE)
        return p

    def add_paragraph(self, text='', style=None):
        """
        Return a paragraph newly added to the end of the document, populated
        with *text* and having paragraph style *style*. *text* can contain
        tab (``\\t``) characters, which are converted to the appropriate XML
        form for a tab. *text* can also include newline (``\\n``) or carriage
        return (``\\r``) characters, each of which is converted to a line
        break.
        """
        return self._document_part.add_paragraph(text, style)

    def add_picture(self, image_path_or_stream, width=None, height=None):
        """
        Return a new picture shape added in its own paragraph at the end of
        the document. The picture contains the image at
        *image_path_or_stream*, scaled based on *width* and *height*. If
        neither width nor height is specified, the picture appears at its
        native size. If only one is specified, it is used to compute
        a scaling factor that is then applied to the unspecified dimension,
        preserving the aspect ratio of the image. The native size of the
        picture is calculated using the dots-per-inch (dpi) value specified
        in the image file, defaulting to 72 dpi if no value is specified, as
        is often the case.
        """
        run = self.add_paragraph().add_run()
        picture = run.add_picture(image_path_or_stream, width, height)
        return picture

    def add_section(self, start_type=WD_SECTION.NEW_PAGE):
        """
        Return a |Section| object representing a new section added at the end
        of the document. The optional *start_type* argument must be a member
        of the :ref:`WdSectionStart` enumeration defaulting to
        ``WD_SECTION.NEW_PAGE`` if not provided.
        """
        return self._document_part.add_section(start_type)

    def add_table(self, rows, cols, style='LightShading-Accent1'):
        """
        Add a table having row and column counts of *rows* and *cols*
        respectively and table style of *style*. If *style* is |None|, a
        table with no style is produced.
        """
        table = self._document_part.add_table(rows, cols)
        if style:
            table.style = style
        return table

    @property
    def core_properties(self):
        """
        A |CoreProperties| object providing read/write access to the core
        properties of this document.
        """
        return self._package.core_properties

    @property
    def inline_shapes(self):
        """
        Return a reference to the |InlineShapes| instance for this document.
        """
        return self._document_part.inline_shapes

    @lazyproperty
    def numbering_part(self):
        """
        Instance of |NumberingPart| for this document. Creates an empty
        numbering part if one is not present.
        """
        try:
            return self._document_part.part_related_by(RT.NUMBERING)
        except KeyError:
            numbering_part = NumberingPart.new()
            self._document_part.relate_to(numbering_part, RT.NUMBERING)
            return numbering_part

    @property
    def paragraphs(self):
        """
        A list of |Paragraph| instances corresponding to the paragraphs in
        the document, in document order. Note that paragraphs within revision
        marks such as ``<w:ins>`` or ``<w:del>`` do not appear in this list.
        """
        return self._document_part.paragraphs

    def save(self, path_or_stream):
        """
        Save this document to *path_or_stream*, which can be either a path to
        a filesystem location (a string) or a file-like object.
        """
        self._package.save(path_or_stream)

    @property
    def sections(self):
        """
        Return a reference to the |Sections| instance for this document.
        """
        return self._document_part.sections

    @lazyproperty
    def styles_part(self):
        """
        Instance of |StylesPart| for this document. Creates an empty styles
        part if one is not present.
        """
        try:
            return self._document_part.part_related_by(RT.STYLES)
        except KeyError:
            styles_part = StylesPart.new()
            self._document_part.relate_to(styles_part, RT.STYLES)
            return styles_part

    @property
    def tables(self):
        """
        A list of |Table| instances corresponding to the tables in the
        document, in document order. Note that tables within revision marks
        such as ``<w:ins>`` or ``<w:del>`` do not appear in this list.
        """
        return self._document_part.tables

    @staticmethod
    def _open(docx):
        """
        Return a (document_part, package) 2-tuple loaded from *docx*, where
        *docx* can be either a path to a ``.docx`` file (a string) or a
        file-like object. If *docx* is ``None``, the built-in default
        document "template" is loaded.
        """
        docx = _default_docx_path if docx is None else docx
        package = Package.open(docx)
        document_part = package.main_document
        if document_part.content_type != CT.WML_DOCUMENT_MAIN:
            tmpl = "file '%s' is not a Word file, content type is '%s'"
            raise ValueError(tmpl % (docx, document_part.content_type))
        return document_part, package
