# Source code for ebooklib.utils

    # This file is part of EbookLib.
    # Copyright (c) 2013 Aleksandar Erkalovic <aerkalov@gmail.com>
    #
    # EbookLib is free software: you can redistribute it and/or modify
    # it under the terms of the GNU Affero General Public License as published by
    # the Free Software Foundation, either version 3 of the License, or
    # (at your option) any later version.
    #
    # EbookLib is distributed in the hope that it will be useful,
    # but WITHOUT ANY WARRANTY; without even the implied warranty of
    # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    # GNU Affero General Public License for more details.
    #
    # You should have received a copy of the GNU Affero General Public License
    # along with EbookLib.  If not, see <http://www.gnu.org/licenses/>.

    import io
    import mimetypes

    from lxml import etree

    mimetype_initialised = False

    def debug(obj):
        import pprint

        pp = pprint.PrettyPrinter(indent=4)
        pp.pprint(obj)

    def parse_string(s):
        try:
            tree = etree.parse(io.BytesIO(s.encode('utf-8')))
        except:
            tree = etree.parse(io.BytesIO(s))

        return tree

    def parse_html_string(s):
        from lxml import html

        utf8_parser = html.HTMLParser(encoding='utf-8')

        html_tree = html.document_fromstring(s, parser=utf8_parser)

        return html_tree

    def guess_type(extenstion):
        global mimetype_initialised

        if not mimetype_initialised:
            mimetypes.init()
            mimetypes.add_type('application/xhtml+xml', '.xhtml')
            mimetype_initialised = True

        return mimetypes.guess_type(extenstion)

    def create_pagebreak(pageref, label=None, html=True):
        from ebooklib.epub import NAMESPACES

        pageref_attributes = {
            '{%s}type' % NAMESPACES['EPUB']: 'pagebreak',
            'title': u'{}'.format(pageref),
            'id': u'{}'.format(pageref),
         }

        pageref_elem = etree.Element('span', pageref_attributes, nsmap={'epub': NAMESPACES['EPUB']})

        if label:
            pageref_elem.text = label

        if html:
            return etree.tostring(pageref_elem, encoding='unicode')

        return pageref_elem

    def get_headers(elem):
        for n in range(1, 7):
            headers = elem.xpath('./h{}'.format(n))

            if len(headers) > 0:
                text = headers[0].text_content().strip()
                if len(text) > 0:
                    return text
        return None

    def get_pages(item):
        body = parse_html_string(item.get_body_content())
        pages = []

        for elem in body.iter():
            if 'epub:type' in elem.attrib:
                if elem.get('id') is not None:
                    _text = None

                    if elem.text is not None and elem.text.strip() != '':
                        _text = elem.text.strip()

                    if _text is None:
                        _text = elem.get('aria-label')

                    if _text is None:
                        _text = get_headers(elem)

                    pages.append((item.get_name(), elem.get('id'), _text or elem.get('id')))

        return pages

    def get_pages_for_items(items):
        pages_from_docs = [get_pages(item) for item in items]

        return [item for pages in pages_from_docs for item in pages]