import collections
import re

from ebook_converter.ebooks.docx.writer.container import create_skeleton, page_size, page_effective_area
from ebook_converter.ebooks.docx.writer.fonts import FontsManager
from ebook_converter.ebooks.docx.writer.images import ImagesManager
from ebook_converter.ebooks.docx.writer.links import LinksManager
from ebook_converter.ebooks.docx.writer.lists import ListsManager
from ebook_converter.ebooks.docx.writer.styles import StylesManager, FloatSpec
from ebook_converter.ebooks.docx.writer.tables import Table
from ebook_converter.ebooks.oeb import base
from ebook_converter.ebooks.oeb import parse_utils
from ebook_converter.ebooks.oeb.stylizer import Stylizer as Sz, Style as St
from ebook_converter.utils.localization import lang_as_iso639_1


def lang_for_tag(tag):
    for attr in ('lang', '{http://www.w3.org/XML/1998/namespace}lang'):
        val = lang_as_iso639_1(tag.get(attr))
        if val:
            return val


class Style(St):

    def __init__(self, *args, **kwargs):
        St.__init__(self, *args, **kwargs)
        self._letterSpacing = None

    @property
    def letterSpacing(self):
        if self._letterSpacing is not None:
            val = self._get('letter-spacing')
            if val == 'normal':
                self._letterSpacing = val
            else:
                self._letterSpacing = self._unit_convert(val)
        return self._letterSpacing


class Stylizer(Sz):

    def style(self, element):
        try:
            return self._styles[element]
        except KeyError:
            return Style(element, self)


class TextRun(object):

    ws_pat = None

    def __init__(self, namespace, style, first_html_parent, lang=None):
        self.first_html_parent = first_html_parent
        if self.ws_pat is None:
            TextRun.ws_pat = self.ws_pat = re.compile(r'\s+')
        self.style = style
        self.texts = []
        self.link = None
        self.lang = lang
        self.parent_style = None
        self.makeelement = namespace.makeelement
        self.descendant_style = None

    def add_text(self, text, preserve_whitespace, bookmark=None, link=None):
        if not preserve_whitespace:
            text = self.ws_pat.sub(' ', text)
            if text.strip() != text:
                # If preserve_whitespace is False, Word ignores leading and
                # trailing whitespace
                preserve_whitespace = True
        self.texts.append((text, preserve_whitespace, bookmark))
        self.link = link

    def add_break(self, clear='none', bookmark=None):
        self.texts.append((None, clear, bookmark))

    def add_image(self, drawing, bookmark=None):
        self.texts.append((drawing, None, bookmark))

    def serialize(self, p, links_manager):
        makeelement = self.makeelement
        parent = p if self.link is None else links_manager.serialize_hyperlink(p, self.link)
        r = makeelement(parent, 'w:r')
        rpr = makeelement(r, 'w:rPr', append=False)
        if getattr(self.descendant_style, 'id', None) is not None:
            makeelement(rpr, 'w:rStyle', w_val=self.descendant_style.id)
        if self.lang:
            makeelement(rpr, 'w:lang', w_bidi=self.lang, w_val=self.lang, w_eastAsia=self.lang)
        if len(rpr) > 0:
            r.append(rpr)

        for text, preserve_whitespace, bookmark in self.texts:
            if bookmark is not None:
                bid = links_manager.bookmark_id
                makeelement(r, 'w:bookmarkStart', w_id=str(bid), w_name=bookmark)
            if text is None:
                makeelement(r, 'w:br', w_clear=preserve_whitespace)
            elif hasattr(text, 'xpath'):
                r.append(text)
            else:
                t = makeelement(r, 'w:t')
                t.text = text or ''
                if preserve_whitespace:
                    t.set('{http://www.w3.org/XML/1998/namespace}space', 'preserve')
            if bookmark is not None:
                makeelement(r, 'w:bookmarkEnd', w_id=str(bid))

    def __repr__(self):
        return repr(self.texts)

    def is_empty(self):
        if not self.texts:
            return True
        if len(self.texts) == 1 and self.texts[0][:2] == ('', False):
            return True
        return False

    @property
    def style_weight(self):
        ans = 0
        for text, preserve_whitespace, bookmark in self.texts:
            if isinstance(text, str):
                ans += len(text)
        return ans


class Block(object):

    def __init__(self, namespace, styles_manager, links_manager, html_block, style, is_table_cell=False, float_spec=None, is_list_item=False, parent_bg=None):
        self.force_not_empty = False
        self.namespace = namespace
        self.bookmarks = set()
        self.list_tag = (html_block, style) if is_list_item else None
        self.is_first_block = False
        self.numbering_id = None
        self.parent_items = None
        self.html_block = html_block
        self.html_tag = parse_utils.barename(html_block.tag)
        self.float_spec = float_spec
        if float_spec is not None:
            float_spec.blocks.append(self)
        self.html_style = style
        self.style = styles_manager.create_block_style(style, html_block, is_table_cell=is_table_cell, parent_bg=parent_bg)
        self.styles_manager, self.links_manager = styles_manager, links_manager
        self.keep_next = False
        self.runs = []
        self.skipped = False
        self.linked_style = None
        self.page_break_before = style['page-break-before'] == 'always'
        self.keep_lines = style['page-break-inside'] == 'avoid'
        self.page_break_after = False
        self.block_lang = None

    def resolve_skipped(self, next_block):
        if not self.is_empty():
            return
        if len(self.html_block) > 0 and self.html_block[0] is next_block.html_block:
            self.skipped = True
            if self.list_tag is not None:
                next_block.list_tag = self.list_tag

    def add_text(self, text, style, ignore_leading_whitespace=False, html_parent=None, is_parent_style=False, bookmark=None, link=None, lang=None):
        ws = style['white-space']
        preserve_whitespace = ws in {'pre', 'pre-wrap', '-o-pre-wrap'}
        ts = self.styles_manager.create_text_style(style, is_parent_style=is_parent_style)
        if self.runs and ts == self.runs[-1].style and link == self.runs[-1].link and lang == self.runs[-1].lang:
            run = self.runs[-1]
        else:
            run = TextRun(self.namespace, ts, self.html_block if html_parent is None else html_parent, lang=lang)
            self.runs.append(run)
        if ignore_leading_whitespace and not preserve_whitespace:
            text = text.lstrip()
        if preserve_whitespace or ws == 'pre-line':
            for text in text.splitlines():
                run.add_text(text, preserve_whitespace, bookmark=bookmark, link=link)
                bookmark = None
                run.add_break()
        else:
            run.add_text(text, preserve_whitespace, bookmark=bookmark, link=link)

    def add_break(self, clear='none', bookmark=None):
        if self.runs:
            run = self.runs[-1]
        else:
            run = TextRun(self.namespace, self.styles_manager.create_text_style(self.html_style), self.html_block)
            self.runs.append(run)
        run.add_break(clear=clear, bookmark=bookmark)

    def add_image(self, drawing, bookmark=None):
        if self.runs:
            run = self.runs[-1]
        else:
            run = TextRun(self.namespace, self.styles_manager.create_text_style(self.html_style), self.html_block)
            self.runs.append(run)
        run.add_image(drawing, bookmark=bookmark)

    def serialize(self, body):
        makeelement = self.namespace.makeelement
        p = makeelement(body, 'w:p')
        end_bookmarks = []
        for bmark in self.bookmarks:
            end_bookmarks.append(str(self.links_manager.bookmark_id))
            makeelement(p, 'w:bookmarkStart', w_id=end_bookmarks[-1], w_name=bmark)
        if self.block_lang:
            rpr = makeelement(p, 'w:rPr')
            makeelement(rpr, 'w:lang', w_val=self.block_lang, w_bidi=self.block_lang, w_eastAsia=self.block_lang)

        ppr = makeelement(p, 'w:pPr')
        if self.keep_next:
            makeelement(ppr, 'w:keepNext')
        if self.float_spec is not None:
            self.float_spec.serialize(self, ppr)
        if self.numbering_id is not None:
            numpr = makeelement(ppr, 'w:numPr')
            makeelement(numpr, 'w:ilvl', w_val=str(self.numbering_id[1]))
            makeelement(numpr, 'w:numId', w_val=str(self.numbering_id[0]))
        if self.linked_style is not None:
            makeelement(ppr, 'w:pStyle', w_val=self.linked_style.id)
        elif self.style.id:
            makeelement(ppr, 'w:pStyle', w_val=self.style.id)
        if self.is_first_block:
            makeelement(ppr, 'w:pageBreakBefore', w_val='off')
        elif self.page_break_before:
            makeelement(ppr, 'w:pageBreakBefore', w_val='on')
        if self.keep_lines:
            makeelement(ppr, 'w:keepLines', w_val='on')
        for run in self.runs:
            run.serialize(p, self.links_manager)
        for bmark in end_bookmarks:
            makeelement(p, 'w:bookmarkEnd', w_id=bmark)

    def __repr__(self):
        return 'Block(%r)' % self.runs
    __str__ = __repr__

    def is_empty(self):
        if self.force_not_empty:
            return False
        for run in self.runs:
            if not run.is_empty():
                return False
        return True


class Blocks(object):

    def __init__(self, namespace, styles_manager, links_manager):
        self.top_bookmark = None
        self.namespace = namespace
        self.styles_manager = styles_manager
        self.links_manager = links_manager
        self.all_blocks = []
        self.pos = 0
        self.current_block = None
        self.items = []
        self.tables = []
        self.current_table = None
        self.open_html_blocks = set()
        self.html_tag_start_blocks = {}

    def current_or_new_block(self, html_tag, tag_style):
        return self.current_block or self.start_new_block(html_tag, tag_style)

    def end_current_block(self):
        if self.current_block is not None:
            self.all_blocks.append(self.current_block)
            if self.current_table is not None and self.current_table.current_row is not None:
                self.current_table.add_block(self.current_block)
            else:
                self.block_map[self.current_block] = len(self.items)
                self.items.append(self.current_block)
                self.current_block.parent_items = self.items
        self.current_block = None

    def start_new_block(self, html_block, style, is_table_cell=False, float_spec=None, is_list_item=False):
        parent_bg = None
        if html_block is not None:
            p = html_block.getparent()
            b = self.html_tag_start_blocks.get(p)
            if b is not None:
                ps = self.styles_manager.styles_for_html_blocks.get(p)
                if ps is not None and ps.background_color is not None:
                    parent_bg = ps.background_color
        self.end_current_block()
        self.current_block = Block(
            self.namespace, self.styles_manager, self.links_manager, html_block, style,
            is_table_cell=is_table_cell, float_spec=float_spec, is_list_item=is_list_item,
            parent_bg=parent_bg)
        self.html_tag_start_blocks[html_block] = self.current_block
        self.open_html_blocks.add(html_block)
        return self.current_block

    def start_new_table(self, html_tag, tag_style=None):
        self.current_table = Table(self.namespace, html_tag, tag_style)
        self.tables.append(self.current_table)

    def start_new_row(self, html_tag, tag_style):
        if self.current_table is None:
            self.start_new_table(html_tag)
        self.current_table.start_new_row(html_tag, tag_style)

    def start_new_cell(self, html_tag, tag_style):
        if self.current_table is None:
            self.start_new_table(html_tag)
        self.current_table.start_new_cell(html_tag, tag_style)

    def finish_tag(self, html_tag):
        if self.current_block is not None and html_tag in self.open_html_blocks:
            start_block = self.html_tag_start_blocks.get(html_tag)
            if start_block is not None and start_block.html_style['page-break-after'] == 'always':
                self.current_block.page_break_after = True
            self.end_current_block()
            self.open_html_blocks.discard(html_tag)

        if self.current_table is not None:
            table_finished = self.current_table.finish_tag(html_tag)
            if table_finished:
                table = self.tables[-1]
                del self.tables[-1]
                if self.tables:
                    self.current_table = self.tables[-1]
                    self.current_table.add_table(table)
                else:
                    self.current_table = None
                    self.block_map[table] = len(self.items)
                    self.items.append(table)

    def serialize(self, body):
        for item in self.items:
            item.serialize(body)

    def delete_block_at(self, pos=None):
        pos = self.pos if pos is None else pos
        block = self.all_blocks[pos]
        del self.all_blocks[pos]
        bpos = self.block_map.pop(block, None)
        if bpos is not None:
            del self.items[bpos]
        else:
            items = self.items if block.parent_items is None else block.parent_items
            items.remove(block)
        block.parent_items = None
        if block.float_spec is not None:
            block.float_spec.blocks.remove(block)
        try:
            next_block = self.all_blocks[pos]
            next_block.bookmarks.update(block.bookmarks)
            for attr in 'page_break_after page_break_before'.split():
                setattr(next_block, attr, getattr(block, attr))
        except (IndexError, KeyError):
            pass

    def __enter__(self):
        self.pos = len(self.all_blocks)
        self.block_map = {}

    def __exit__(self, etype, value, traceback):
        if value is not None:
            return  # Since there was an exception, the data structures are not in a consistent state
        if self.current_block is not None:
            self.all_blocks.append(self.current_block)
        self.current_block = None
        if len(self.all_blocks) > self.pos and self.all_blocks[self.pos].is_empty():
            # Delete the empty block corresponding to the <body> tag when the
            # body tag has no inline content before its first sub-block
            self.delete_block_at(self.pos)
        if self.pos > 0 and self.pos < len(self.all_blocks):
            # Insert a page break corresponding to the start of the html file
            self.all_blocks[self.pos].page_break_before = True
            if self.top_bookmark is not None:
                self.all_blocks[self.pos].bookmarks.add(self.top_bookmark)
        self.top_bookmark = None
        self.block_map = {}

    def apply_page_break_after(self):
        for i, block in enumerate(self.all_blocks):
            if block.page_break_after and i < len(self.all_blocks) - 1:
                next_block = self.all_blocks[i + 1]
                if next_block.parent_items is block.parent_items and block.parent_items is self.items:
                    next_block.page_break_before = True

    def resolve_language(self):
        default_lang = self.styles_manager.document_lang
        for block in self.all_blocks:
            count = collections.Counter()
            for run in block.runs:
                count[run.lang] += 1
            if count:
                block.block_lang = bl = count.most_common(1)[0][0]
                for run in block.runs:
                    if run.lang == bl:
                        run.lang = None
                if bl == default_lang:
                    block.block_lang = None

    def __repr__(self):
        return 'Block(%r)' % self.runs


class Convert(object):

    # Word does not apply default styling to hyperlinks, so we ensure they get
    # default styling (the conversion pipeline does not apply any styling to
    # them).
    base_css = '''
    a[href] { text-decoration: underline; color: blue }
    '''

    def __init__(self, oeb, docx, mi, add_cover, add_toc):
        self.oeb, self.docx, self.add_cover, self.add_toc = oeb, docx, add_cover, add_toc
        self.log, self.opts = docx.log, docx.opts
        self.mi = mi
        self.cover_img = None
        p = self.opts.output_profile
        p.width_pts, p.height_pts = page_effective_area(self.opts)

    def __call__(self):
        from ebook_converter.ebooks.oeb.transforms.rasterize import SVGRasterizer
        self.svg_rasterizer = SVGRasterizer(base_css=self.base_css)
        self.svg_rasterizer(self.oeb, self.opts)

        self.styles_manager = StylesManager(self.docx.namespace, self.log, self.mi.language)
        self.links_manager = LinksManager(self.docx.namespace, self.docx.document_relationships, self.log)
        self.images_manager = ImagesManager(self.oeb, self.docx.document_relationships, self.opts)
        self.lists_manager = ListsManager(self.docx)
        self.fonts_manager = FontsManager(self.docx.namespace, self.oeb, self.opts)
        self.blocks = Blocks(self.docx.namespace, self.styles_manager, self.links_manager)
        self.current_link = self.current_lang = None

        for item in self.oeb.spine:
            self.log.debug('Processing', item.href)
            self.process_item(item)
        if self.add_toc:
            self.links_manager.process_toc_links(self.oeb)

        if self.add_cover and self.oeb.metadata.cover and str(self.oeb.metadata.cover[0]) in self.oeb.manifest.ids:
            cover_id = str(self.oeb.metadata.cover[0])
            item = self.oeb.manifest.ids[cover_id]
            self.cover_img = self.images_manager.read_image(item.href)

        all_blocks = self.blocks.all_blocks
        remove_blocks = []
        for i, block in enumerate(all_blocks):
            try:
                nb = all_blocks[i+1]
            except IndexError:
                break
            block.resolve_skipped(nb)
            if block.skipped:
                remove_blocks.append((i, block))
        for pos, block in reversed(remove_blocks):
            self.blocks.delete_block_at(pos)
        self.blocks.all_blocks[0].is_first_block = True
        self.blocks.apply_page_break_after()
        self.blocks.resolve_language()

        if self.cover_img is not None:
            self.cover_img = self.images_manager.create_cover_markup(self.cover_img, self.opts.preserve_cover_aspect_ratio, *page_size(self.opts))
        self.lists_manager.finalize(all_blocks)
        self.styles_manager.finalize(all_blocks)
        self.write()

    def process_item(self, item):
        self.current_item = item
        stylizer = self.svg_rasterizer.stylizer_cache.get(item)
        if stylizer is None:
            stylizer = Stylizer(item.data, item.href, self.oeb, self.opts, profile=self.opts.output_profile, base_css=self.base_css)
        self.abshref = self.images_manager.abshref = item.abshref

        self.current_lang = lang_for_tag(item.data) or self.styles_manager.document_lang
        for i, body in enumerate(base.XPath('//h:body')(item.data)):
            with self.blocks:
                self.blocks.top_bookmark = self.links_manager.bookmark_for_anchor(self.links_manager.top_anchor, self.current_item, body)
                self.process_tag(body, stylizer, is_first_tag=i == 0)

    def process_tag(self, html_tag, stylizer, is_first_tag=False, float_spec=None):
        tagname = parse_utils.barename(html_tag.tag)
        tag_style = stylizer.style(html_tag)
        ignore_tag_contents = tagname in {'script', 'style', 'title', 'meta'} or tag_style.is_hidden
        display = tag_style._get('display')
        is_block = False

        if not ignore_tag_contents:
            previous_link = self.current_link
            if tagname == 'a' and html_tag.get('href'):
                self.current_link = (self.current_item, html_tag.get('href'), html_tag.get('title'))
            previous_lang = self.current_lang
            tag_lang = lang_for_tag(html_tag)
            if tag_lang:
                self.current_lang = tag_lang

            is_float = tag_style['float'] in {'left', 'right'} and not is_first_tag
            if float_spec is None and is_float:
                float_spec = FloatSpec(self.docx.namespace, html_tag, tag_style)

            if display in {'inline', 'inline-block'} or tagname == 'br':  # <br> has display:block but we dont want to start a new paragraph
                if is_float and float_spec.is_dropcaps:
                    self.add_block_tag(tagname, html_tag, tag_style, stylizer, float_spec=float_spec)
                    float_spec = None
                else:
                    self.add_inline_tag(tagname, html_tag, tag_style, stylizer)
            elif display == 'list-item':
                self.add_block_tag(tagname, html_tag, tag_style, stylizer, is_list_item=True)
            elif display.startswith('table') or display == 'inline-table':
                if display == 'table-cell':
                    self.blocks.start_new_cell(html_tag, tag_style)
                    self.add_block_tag(tagname, html_tag, tag_style, stylizer, is_table_cell=True)
                elif display == 'table-row':
                    self.blocks.start_new_row(html_tag, tag_style)
                elif display in {'table', 'inline-table'}:
                    self.blocks.end_current_block()
                    self.blocks.start_new_table(html_tag, tag_style)
            else:
                if tagname == 'img' and is_float:
                    # Image is floating so dont start a new paragraph for it
                    self.add_inline_tag(tagname, html_tag, tag_style, stylizer)
                else:
                    if tagname == 'hr':
                        for edge in 'right bottom left'.split():
                            tag_style.set('border-%s-style' % edge, 'none')
                    self.add_block_tag(tagname, html_tag, tag_style, stylizer, float_spec=float_spec)

            for child in html_tag.iterchildren():
                if isinstance(getattr(child, 'tag', None), (str, bytes)):
                    self.process_tag(child, stylizer, float_spec=float_spec)
                else:  # Comment/PI/etc.
                    tail = getattr(child, 'tail', None)
                    if tail:
                        block = self.create_block_from_parent(html_tag, stylizer)
                        block.add_text(tail, tag_style, is_parent_style=False, link=self.current_link, lang=self.current_lang)

            is_block = html_tag in self.blocks.open_html_blocks
            self.blocks.finish_tag(html_tag)
            if is_block and tag_style['page-break-after'] == 'avoid':
                self.blocks.all_blocks[-1].keep_next = True

            self.current_link = previous_link
            self.current_lang = previous_lang

        # Now, process the tail if any

        if display == 'table-row':
            return  # We ignore the tail for these tags

        ignore_whitespace_tail = is_block or display.startswith('table')
        if not is_first_tag and html_tag.tail and (not ignore_whitespace_tail or not html_tag.tail.isspace()):
            # Ignore trailing space after a block tag, as otherwise it will
            # become a new empty paragraph
            block = self.create_block_from_parent(html_tag, stylizer)
            block.add_text(html_tag.tail, stylizer.style(html_tag.getparent()), is_parent_style=True, link=self.current_link, lang=self.current_lang)

    def create_block_from_parent(self, html_tag, stylizer):
        parent = html_tag.getparent()
        block = self.blocks.current_or_new_block(parent, stylizer.style(parent))
        # Do not inherit page-break-before from parent
        block.page_break_before = False
        return block

    def add_block_tag(self, tagname, html_tag, tag_style, stylizer, is_table_cell=False, float_spec=None, is_list_item=False):
        block = self.blocks.start_new_block(
            html_tag, tag_style, is_table_cell=is_table_cell, float_spec=float_spec, is_list_item=is_list_item)
        anchor = html_tag.get('id') or html_tag.get('name')
        if anchor:
            block.bookmarks.add(self.bookmark_for_anchor(anchor, html_tag))
        if tagname == 'img':
            self.images_manager.add_image(html_tag, block, stylizer, as_block=True)
        else:
            text = html_tag.text
            if text:
                block.add_text(text, tag_style, ignore_leading_whitespace=True, is_parent_style=True, link=self.current_link, lang=self.current_lang)
            elif tagname == 'li' and len(html_tag) and parse_utils.barename(html_tag[0].tag) in ('ul', 'ol') and len(html_tag[0]):
                block.force_not_empty = True

    def add_inline_tag(self, tagname, html_tag, tag_style, stylizer):
        anchor = html_tag.get('id') or html_tag.get('name') or None
        bmark = None
        if anchor:
            bmark = self.bookmark_for_anchor(anchor, html_tag)
        if tagname == 'br':
            if html_tag.tail or html_tag is not tuple(html_tag.getparent().iterchildren('*'))[-1]:
                block = self.create_block_from_parent(html_tag, stylizer)
                block.add_break(clear={'both':'all', 'left':'left', 'right':'right'}.get(tag_style['clear'], 'none'), bookmark=bmark)
        elif tagname == 'img':
            block = self.create_block_from_parent(html_tag, stylizer)
            self.images_manager.add_image(html_tag, block, stylizer, bookmark=bmark)
        else:
            if html_tag.text:
                block = self.create_block_from_parent(html_tag, stylizer)
                block.add_text(html_tag.text, tag_style, is_parent_style=False, bookmark=bmark, link=self.current_link, lang=self.current_lang)
            elif bmark:
                block = self.create_block_from_parent(html_tag, stylizer)
                block.add_text('', tag_style, is_parent_style=False, bookmark=bmark, link=self.current_link, lang=self.current_lang)

    def bookmark_for_anchor(self, anchor, html_tag):
        return self.links_manager.bookmark_for_anchor(anchor, self.current_item, html_tag)

    def write(self):
        self.docx.document, self.docx.styles, body = create_skeleton(self.opts)
        self.blocks.serialize(body)
        body.append(body[0])  # Move <sectPr> to the end
        if self.links_manager.toc:
            self.links_manager.serialize_toc(body, self.styles_manager.primary_heading_style)
        if self.cover_img is not None:
            self.images_manager.write_cover_block(body, self.cover_img)
        self.styles_manager.serialize(self.docx.styles)
        self.images_manager.serialize(self.docx.images)
        self.fonts_manager.serialize(self.styles_manager.text_styles, self.docx.font_table, self.docx.embedded_fonts, self.docx.fonts)
        self.lists_manager.serialize(self.docx.numbering)