import mimetypes
import os
import pkg_resources
import re
import string
import sys
import urllib.parse
from xml.sax import saxutils

from ebook_converter import constants as const
from ebook_converter.utils import date
from ebook_converter.ebooks.oeb import base
from ebook_converter.ebooks.oeb.base import XPath, xml2text, urlnormalize
from ebook_converter.library.comments import comments_to_html, markdown
from ebook_converter.ebooks.chardet import strip_encoding_declarations
from ebook_converter.ebooks.metadata import fmt_sidx, rating_to_stars


JACKET_XPATH = '//h:meta[@name="calibre-content" and @content="jacket"]'


class SafeFormatter(string.Formatter):

    def get_value(self, *args, **kwargs):
        try:
            return string.Formatter.get_value(self, *args, **kwargs)
        except KeyError:
            return ''


class Base(object):

    def remove_images(self, item, limit=1):
        path = XPath('//h:img[@src]')
        removed = 0
        for img in path(item.data):
            if removed >= limit:
                break
            href = item.abshref(img.get('src'))
            image = self.oeb.manifest.hrefs.get(href)
            if image is None:
                href = urlnormalize(href)
                image = self.oeb.manifest.hrefs.get(href)
            if image is not None:
                self.oeb.manifest.remove(image)
                self.oeb.guide.remove_by_href(href)
                img.getparent().remove(img)
                removed += 1
        return removed


class RemoveFirstImage(Base):

    def remove_first_image(self):
        deleted_item = None
        for item in self.oeb.spine:
            if XPath(JACKET_XPATH)(item.data):
                continue
            removed = self.remove_images(item)
            if removed > 0:
                self.log('Removed first image')
                body = XPath('//h:body')(item.data)
                if body:
                    raw = xml2text(body[0]).strip()
                    imgs = XPath('//h:img|//svg:svg')(item.data)
                    if not raw and not imgs:
                        self.log('Removing %s as it has no content' %
                                 item.href)
                        self.oeb.manifest.remove(item)
                        deleted_item = item
                break
        else:
            self.log.warn('Could not find first image to remove')
        if deleted_item is not None:
            for item in list(self.oeb.toc):
                href = urllib.parse.urldefrag(item.href)[0]
                if href == deleted_item.href:
                    self.oeb.toc.remove(item)
            self.oeb.guide.remove_by_href(deleted_item.href)

    def __call__(self, oeb, opts, metadata):
        """
        Add metadata in jacket.xhtml if specified in opts
        If not specified, remove previous jacket instance
        """
        self.oeb, self.opts, self.log = oeb, opts, oeb.log
        if opts.remove_first_image:
            self.remove_first_image()


class Jacket(Base):
    """
    Book jacket manipulation. Remove first image and insert comments at start
    of book.
    """

    def insert_metadata(self, mi):
        self.log('Inserting metadata into book...')

        try:
            tags = list(map(str, self.oeb.metadata.subject))
        except Exception:
            tags = []

        try:
            comments = str(self.oeb.metadata.description[0])
        except Exception:
            comments = ''

        try:
            title = str(self.oeb.metadata.title[0])
        except Exception:
            title = 'Unknown'

        try:
            authors = list(map(str, self.oeb.metadata.creator))
        except Exception:
            authors = ['Unknown']

        root = render_jacket(mi, self.opts.output_profile,
                             alt_title=title, alt_tags=tags,
                             alt_authors=authors,
                             alt_comments=comments,
                             rescale_fonts=True)
        id, href = self.oeb.manifest.generate('calibre_jacket', 'jacket.xhtml')

        jacket = self.oeb.manifest.add(id, href, mimetypes.guess_type(href)[0],
                                       data=root)
        self.oeb.spine.insert(0, jacket, True)
        self.oeb.inserted_metadata_jacket = jacket
        for img, path in referenced_images(root):
            self.oeb.log('Embedding referenced image %s into jacket' % path)
            ext = path.rpartition('.')[-1].lower()
            item_id, href = self.oeb.manifest.generate('jacket_image',
                                                       'jacket_img.' + ext)
            with open(path, 'rb') as f:
                item = self.oeb.manifest.add(
                    item_id, href, mimetypes.guess_type(href)[0],
                    data=f.read())
            item.unload_data_from_memory()
            img.set('src', jacket.relhref(item.href))

    def remove_existing_jacket(self):
        for x in self.oeb.spine[:4]:
            if XPath(JACKET_XPATH)(x.data):
                self.remove_images(x, limit=sys.maxsize)
                self.oeb.manifest.remove(x)
                self.log('Removed existing jacket')
                break

    def __call__(self, oeb, opts, metadata):
        """
        Add metadata in jacket.xhtml if specified in opts
        If not specified, remove previous jacket instance
        """
        self.oeb, self.opts, self.log = oeb, opts, oeb.log
        self.remove_existing_jacket()
        if opts.insert_metadata:
            self.insert_metadata(metadata)

# Render Jacket {{{


def get_rating(rating, rchar, e_rchar):
    ans = ''
    try:
        num = float(rating) / 2
    except Exception:
        return ans
    num = max(0, num)
    num = min(num, 5)
    if num < 1:
        return ans

    ans = ("%s%s") % (rchar * int(num), e_rchar * (5 - int(num)))
    return ans


class Series(str):

    def __new__(self, series, series_index):
        if series and series_index is not None:
            _roman = saxutils.escape(fmt_sidx(series_index, use_roman=True))
            _no_roman = saxutils.escape(fmt_sidx(series_index,
                                                 use_roman=False))
            roman = '{1} of <em>{0}</em>'.format(saxutils.escape(series),
                                                 _roman)
            combined = '{1} of <em>{0}</em>'.format(saxutils.escape(series),
                                                    _no_roman)
        else:
            combined = roman = saxutils.escape(series or u'')
        s = str.__new__(self, combined)
        s.roman = roman
        s.name = saxutils.escape(series or '')
        s.number = saxutils.escape(fmt_sidx(series_index or 1.0,
                                            use_roman=False))
        s.roman_number = saxutils.escape(fmt_sidx(series_index or 1.0,
                                                  use_roman=True))
        return s


class Tags(str):

    def __new__(self, tags, output_profile):
        tags = [saxutils.escape(x) for x in tags or ()]
        t = str.__new__(self, ', '.join(tags))
        t.alphabetical = ', '.join(sorted(tags))
        t.tags_list = tags
        return t


def postprocess_jacket(root, output_profile, has_data):
    # Post-process the generated html to strip out empty header items

    def extract(tag):
        parent = tag.getparent()
        idx = parent.index(tag)
        parent.remove(tag)
        if tag.tail:
            if idx == 0:
                parent.text = (parent.text or '') + tag.tail
            else:
                if idx >= len(parent):
                    idx = -1
                parent[-1].tail = (parent[-1].tail or '') + tag.tail

    def extract_class(cls):
        for tag in root.xpath('//*[@class="_"]'.replace('_', cls)):
            extract(tag)

    for key in 'series rating tags'.split():
        if not has_data[key]:
            extract_class('cbj_' + key)
    if not has_data['pubdate']:
        extract_class('cbj_pubdata')
    if output_profile.short_name != 'kindle':
        extract_class('cbj_kindle_banner_hr')


def render_jacket(mi, output_profile, alt_title='Unknown', alt_tags=[],
                  alt_comments='', alt_publisher='', rescale_fonts=False,
                  alt_authors=None):
    with open(pkg_resources.resource_filename('ebook_converter',
                                              'data/jacket/stylesheet.css'),
              'rb') as fobj:
        css = fobj.read().decode()
    with open(pkg_resources.resource_filename('ebook_converter',
                                              'data/jacket/template.xhtml'),
              'rb') as fobj:
        template = fobj.read().decode()

    template = re.sub(r'<!--.*?-->', '', template, flags=re.DOTALL)
    css = re.sub(r'/\*.*?\*/', '', css, flags=re.DOTALL)

    try:
        title_str = alt_title if mi.is_null('title') else mi.title
    except Exception:
        title_str = 'Unknown'
    title_str = saxutils.escape(title_str)
    title = '<span class="title">%s</span>' % title_str

    series = Series(mi.series, mi.series_index)
    try:
        if not mi.is_null('publisher'):
            publisher = mi.publisher
        else:
            publisher = alt_publisher
    except Exception:
        publisher = ''
    publisher = saxutils.escape(publisher)

    try:
        if date.is_date_undefined(mi.pubdate):
            pubdate = ''
        else:
            dt = date.as_local_time(mi.pubdate)
            pubdate = date.strftime('%Y', dt.timetuple())
    except Exception:
        pubdate = ''

    rating = get_rating(mi.rating, output_profile.ratings_char,
                        output_profile.empty_ratings_char)

    tags = Tags((mi.tags if mi.tags else alt_tags), output_profile)

    comments = mi.comments if mi.comments else alt_comments
    comments = comments.strip()
    if comments:
        comments = comments_to_html(comments)

    orig = mi.authors
    if mi.is_null('authors'):
        mi.authors = list(alt_authors or ('Unknown',))
    try:
        author = mi.format_authors()
    except Exception:
        author = ''
    mi.authors = orig
    author = saxutils.escape(author)
    has_data = {}

    def generate_html(comments):
        args = {'author': author,
                'comments': comments,
                'css': css,
                'footer': '',
                'pubdate': pubdate,
                'pubdate_label': 'Published',
                'publisher': publisher,
                'rating': rating,
                'rating_label': 'Rating',
                'searchable_tags': ' '.join(saxutils.escape(t) + 'ttt'
                                            for t in tags.tags_list),
                'series': series,
                'series_label': 'Series',
                'tags': tags,
                'tags_label': 'Tags',
                'title': title,
                'title_str': title_str,
                'xmlns': const.XHTML_NS}

        for key in mi.custom_field_keys():
            m = mi.get_user_metadata(key, False) or {}
            try:
                display_name, val = mi.format_field_extended(key)[:2]
                dkey = key.replace('#', '_')
                dt = m.get('datatype')
                if dt == 'series':
                    args[dkey] = Series(mi.get(key), mi.get(key + '_index'))
                elif dt == 'rating':
                    args[dkey] = rating_to_stars(mi.get(key),
                                                 m.get('display', {})
                                                 .get('allow_half_stars',
                                                      False))
                elif dt == 'comments':
                    val = val or ''
                    display = m.get('display', {})
                    ctype = display.get('interpret_as') or 'html'
                    if ctype == 'long-text':
                        val = ('<pre style="white-space:pre-wrap">%s</pre>' %
                               saxutils.escape(val))
                    elif ctype == 'short-text':
                        val = '<span>%s</span>' % saxutils.escape(val)
                    elif ctype == 'markdown':
                        val = markdown(val)
                    else:
                        val = comments_to_html(val)
                    args[dkey] = val
                else:
                    args[dkey] = saxutils.escape(val)
                args[dkey+'_label'] = saxutils.escape(display_name)
            except Exception:
                # if the val (custom column contents) is None, don't add to
                # args
                pass

        if False:
            print("Custom column values available in jacket template:")
            for key in args.keys():
                if key.startswith('_') and not key.endswith('_label'):
                    print(" %s: %s" % ('#' + key[1:], args[key]))

        # Used in the comment describing use of custom columns in templates
        # Don't change this unless you also change it in template.xhtml
        args['_genre_label'] = args.get('_genre_label', '{_genre_label}')
        args['_genre'] = args.get('_genre', '{_genre}')

        formatter = SafeFormatter()
        generated_html = formatter.format(template, **args)
        has_data['series'] = bool(series)
        has_data['tags'] = bool(tags)
        has_data['rating'] = bool(rating)
        has_data['pubdate'] = bool(pubdate)

        return strip_encoding_declarations(generated_html)

    from ebook_converter.ebooks.oeb.polish.parsing import parse
    raw = generate_html(comments)
    root = parse(raw, line_numbers=False, force_html5_parse=True)

    if rescale_fonts:
        # We ensure that the conversion pipeline will set the font sizes for
        # text in the jacket to the same size as the font sizes for the rest of
        # the text in the book. That means that as long as the jacket uses
        # relative font sizes (em or %), the post conversion font size will be
        # the same as for text in the main book. So text with size x em will
        # be rescaled to the same value in both the jacket and the main
        # content.
        #
        # We cannot use data-calibre-rescale 100 on the body tag as that will
        # just give the body tag a font size of 1em, which is useless.
        for body in root.xpath('//*[local-name()="body"]'):
            fw = body.makeelement(base.tag('xhtml', 'div'))
            fw.set('data-calibre-rescale', '100')
            for child in body:
                fw.append(child)
            body.append(fw)
    postprocess_jacket(root, output_profile, has_data)
    from ebook_converter.ebooks.oeb.polish.pretty import pretty_html_tree
    pretty_html_tree(None, root)
    return root

# }}}


def linearize_jacket(oeb):
    for x in oeb.spine[:4]:
        if XPath(JACKET_XPATH)(x.data):
            for e in XPath('//h:table|//h:tr|//h:th')(x.data):
                e.tag = base.tag('xhtml', 'div')
            for e in XPath('//h:td')(x.data):
                e.tag = base.tag('xhtml', 'span')
            break


def referenced_images(root):
    for img in XPath('//h:img[@src]')(root):
        src = img.get('src')
        if src.startswith('file://'):
            path = src[7:]
            if os.path.exists(path):
                yield img, path