# coding: utf-8
from __future__ import (
    absolute_import,
    print_function,
    unicode_literals,
)

from pydocx.models import XmlModel, XmlCollection, XmlChild
from pydocx.openxml.wordprocessing.hyperlink import Hyperlink
from pydocx.openxml.wordprocessing.paragraph_properties import ParagraphProperties  # noqa
from pydocx.openxml.wordprocessing.run import Run
from pydocx.openxml.wordprocessing.tab_char import TabChar
from pydocx.openxml.wordprocessing.text import Text
from pydocx.openxml.wordprocessing.smart_tag_run import SmartTagRun
from pydocx.openxml.wordprocessing.inserted_run import InsertedRun
from pydocx.openxml.wordprocessing.deleted_run import DeletedRun
from pydocx.openxml.wordprocessing.sdt_run import SdtRun
from pydocx.openxml.wordprocessing.simple_field import SimpleField


class Paragraph(XmlModel):
    XML_TAG = 'p'

    properties = XmlChild(type=ParagraphProperties)

    children = XmlCollection(
        Run,
        Hyperlink,
        SmartTagRun,
        InsertedRun,
        DeletedRun,
        SdtRun,
        SimpleField,
    )

    def __init__(self, **kwargs):
        super(Paragraph, self).__init__(**kwargs)
        self._effective_properties = None

    @property
    def effective_properties(self):
        # TODO need to calculate effective properties like Run
        if not self._effective_properties:
            properties = self.properties
            self._effective_properties = properties
        return self._effective_properties

    def has_structured_document_parent(self):
        from pydocx.openxml.wordprocessing import SdtBlock
        return self.has_ancestor(SdtBlock)

    def get_style_chain_stack(self):
        if not self.properties:
            return

        parent_style = self.properties.parent_style
        if not parent_style:
            return

        # TODO the getattr is necessary because of footnotes. From the context
        # of a footnote, a paragraph's container is the footnote part, which
        # doesn't have access to the style_definitions_part
        part = getattr(self.container, 'style_definitions_part', None)
        if part:
            style_stack = part.get_style_chain_stack('paragraph', parent_style)
            for result in style_stack:
                yield result

    @property
    def heading_style(self):
        if hasattr(self, '_heading_style'):
            return getattr(self, '_heading_style')
        style_stack = self.get_style_chain_stack()
        heading_style = None
        for style in style_stack:
            if style.is_a_heading():
                heading_style = style
                break
        self.heading_style = heading_style
        return heading_style

    @heading_style.setter
    def heading_style(self, style):
        self._heading_style = style

    def get_numbering_definition(self):
        # TODO add memoization

        # TODO the getattr is necessary because of footnotes. From the context
        # of a footnote, a paragraph's container is the footnote part, which
        # doesn't have access to the numbering_definitions_part
        part = getattr(self.container, 'numbering_definitions_part', None)
        if not part:
            return
        if not self.effective_properties:
            return
        numbering_properties = self.effective_properties.numbering_properties
        if not numbering_properties:
            return
        return part.numbering.get_numbering_definition(
            num_id=numbering_properties.num_id,
        )

    def get_numbering_level(self):
        # TODO add memoization
        numbering_definition = self.get_numbering_definition()
        if not numbering_definition:
            return
        if not self.effective_properties:
            return
        numbering_properties = self.effective_properties.numbering_properties
        if not numbering_properties:
            return
        return numbering_definition.get_level(
            level_id=numbering_properties.level_id,
        )

    @property
    def runs(self):
        for p_child in self.children:
            if isinstance(p_child, Run):
                yield p_child

    def get_text(self, tab_char=None):
        '''
        Return a string of all of the contained Text nodes concatenated
        together. If `tab_char` is set, then any TabChar encountered will be
        represented in the returned text using the specified string.

        For example:

        Given the following paragraph XML definition:

            <p>
                <r>
                    <t>abc</t>
                </r>
                <r>
                    <t>def</t>
                </r>
            </p>

        `get_text()` will return 'abcdef'
        '''

        text = []
        for run in self.runs:
            for r_child in run.children:
                if isinstance(r_child, Text):
                    if r_child.text:
                        text.append(r_child.text)
                if tab_char and isinstance(r_child, TabChar):
                    text.append(tab_char)
        return ''.join(text)

    def get_number_of_initial_tabs(self):
        '''
        Return the number of initial TabChars.
        '''
        tab_count = 0
        for p_child in self.children:
            if isinstance(p_child, Run):
                for r_child in p_child.children:
                    if isinstance(r_child, TabChar):
                        tab_count += 1
                    else:
                        break
            else:
                break
        return tab_count