# -*- coding: utf-8 -*-
# Copyright (c) 2012 Roberto Alsina y otros.

# Permission is hereby granted, free of charge, to any
# person obtaining a copy of this software and associated
# documentation files (the "Software"), to deal in the
# Software without restriction, including without limitation
# the rights to use, copy, modify, merge, publish,
# distribute, sublicense, and/or sell copies of the
# Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice
# shall be included in all copies or substantial portions of
# the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY
# KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
# WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
# PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS
# OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
# OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
# OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
# SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

from __future__ import unicode_literals, print_function

import codecs
from collections import defaultdict
import os
import re
import string

import lxml.html

from .utils import to_datetime, slugify, bytes_str, Functionary, LocaleBorg

__all__ = ['Post']

TEASER_REGEXP = re.compile('<!--\s*TEASER_END(:(.+))?\s*-->', re.IGNORECASE)


class Post(object):

    """Represents a blog post or web page."""

    def __init__(
        self, source_path, cache_folder, destination, use_in_feeds,
        translations, default_lang, base_url, messages, template_name,
        file_metadata_regexp=None, strip_index_html=False, tzinfo=None,
        skip_untranslated=False,
    ):
        """Initialize post.

        The source path is the .txt post file. From it we calculate
        the meta file, as well as any translations available, and
        the .html fragment file path.
        """
        self.translated_to = set([])
        self._prev_post = None
        self._next_post = None
        self.base_url = base_url
        self.is_draft = False
        self.is_mathjax = False
        self.strip_index_html = strip_index_html
        self.source_path = source_path  # posts/blah.txt
        self.post_name = os.path.splitext(source_path)[0]  # posts/blah
        # cache/posts/blah.html
        self.base_path = os.path.join(cache_folder, self.post_name + ".html")
        self.metadata_path = self.post_name + ".meta"  # posts/blah.meta
        self.folder = destination
        self.translations = translations
        self.default_lang = default_lang
        self.messages = messages
        self.skip_untranslated = skip_untranslated
        self._template_name = template_name

        default_metadata = get_meta(self, file_metadata_regexp)

        self.meta = Functionary(lambda: None, self.default_lang)
        self.meta[default_lang] = default_metadata

        # Load internationalized metadata
        for lang in translations:
            if lang != default_lang:
                if os.path.isfile(self.source_path + "." + lang):
                    self.translated_to.add(lang)

                meta = defaultdict(lambda: '')
                meta.update(default_metadata)
                meta.update(get_meta(self, file_metadata_regexp, lang))
                self.meta[lang] = meta
            elif os.path.isfile(self.source_path):
                self.translated_to.add(default_lang)

        if not self.is_translation_available(default_lang):
            # Special case! (Issue #373)
            # Fill default_metadata with stuff from the other languages
            for lang in sorted(self.translated_to):
                default_metadata.update(self.meta[lang])

        if 'title' not in default_metadata or 'slug' not in default_metadata \
                or 'date' not in default_metadata:
            raise OSError("You must set a title (found '{0}'), a slug (found "
                          "'{1}') and a date (found '{2}')! [in file "
                          "{3}]".format(default_metadata.get('title', None),
                                        default_metadata.get('slug', None),
                                        default_metadata.get('date', None),
                                        source_path))

        # If timezone is set, build localized datetime.
        self.date = to_datetime(self.meta[default_lang]['date'], tzinfo)

        is_draft = False
        is_retired = False
        self._tags = {}
        for lang in self.translated_to:
            self._tags[lang] = [x.strip() for x in self.meta[lang]['tags'].split(',')]
            self._tags[lang] = [t for t in self._tags[lang] if t]
            if 'draft' in self._tags[lang]:
                is_draft = True
                self._tags[lang].remove('draft')
            if 'retired' in self._tags[lang]:
                is_retired = True
                self._tags[lang].remove('retired')

        # While draft comes from the tags, it's not really a tag
        self.is_draft = is_draft
        self.use_in_feeds = use_in_feeds and not is_draft and not is_retired

        # If mathjax is a tag, then enable mathjax rendering support
        self.is_mathjax = 'mathjax' in self.tags

    @property
    def alltags(self):
        """This is ALL the tags for this post."""
        tags = []
        for l in self._tags:
            tags.extend(self._tags[l])
        return list(set(tags))

    @property
    def tags(self):
        lang = self.current_lang()
        if lang in self._tags:
            return self._tags[lang]
        elif self.default_lang in self._tags:
            return self._tags[self.default_lang]
        else:
            return []

    @property
    def prev_post(self):
        lang = self.current_lang()
        rv = self._prev_post
        while self.skip_untranslated:
            if rv is None:
                break
            if rv.is_translation_available(lang):
                break
            rv = rv._prev_post
        return rv

    @prev_post.setter  # NOQA
    def prev_post(self, v):
        self._prev_post = v

    @property
    def next_post(self):
        lang = self.current_lang()
        rv = self._next_post
        while self.skip_untranslated:
            if rv is None:
                break
            if rv.is_translation_available(lang):
                break
            rv = rv._next_post
        return rv

    @next_post.setter  # NOQA
    def next_post(self, v):
        self._next_post = v

    @property
    def template_name(self):
        return self.meta('template') or self._template_name

    def _add_old_metadata(self):
        # Compatibility for themes up to Nikola 5.4.1
        # TODO: remove before Nikola 6
        self.pagenames = {}
        self.titles = {}
        for lang in self.translations:
            self.pagenames[lang] = self.meta[lang]['slug']
            self.titles[lang] = self.meta[lang]['title']

    def formatted_date(self, date_format):
        """Return the formatted date, as unicode."""
        fmt_date = self.date.strftime(date_format)
        # Issue #383, this changes from py2 to py3
        if isinstance(fmt_date, bytes_str):
            fmt_date = fmt_date.decode('utf8')
        return fmt_date

    def current_lang(self):
        """Return the currently set locale, if it's one of the
        available translations, or default_lang."""
        lang = LocaleBorg().current_lang
        if lang:
            if lang in self.translations:
                return lang
            lang = lang.split('_')[0]
            if lang in self.translations:
                return lang
        # whatever
        return self.default_lang

    def title(self, lang=None):
        """Return localized title.

        If lang is not specified, it will use the currently set locale,
        because templates set it.
        """
        if lang is None:
            lang = self.current_lang()
        return self.meta[lang]['title']

    def description(self, lang=None):
        """Return localized description."""
        if lang is None:
            lang = self.current_lang()
        return self.meta[lang]['description']

    def deps(self, lang):
        """Return a list of dependencies to build this post's page."""
        deps = []
        if self.default_lang in self.translated_to:
            deps.append(self.base_path)
        if lang != self.default_lang:
            deps += [self.base_path + "." + lang]
        deps += self.fragment_deps(lang)
        return deps

    def fragment_deps(self, lang):
        """Return a list of dependencies to build this post's fragment."""
        deps = []
        if self.default_lang in self.translated_to:
            deps.append(self.source_path)
        if os.path.isfile(self.metadata_path):
            deps.append(self.metadata_path)
        dep_path = self.base_path + '.dep'
        if os.path.isfile(dep_path):
            with codecs.open(dep_path, 'rb+', 'utf8') as depf:
                deps.extend([l.strip() for l in depf.readlines()])
        if lang != self.default_lang:
            lang_deps = list(filter(os.path.exists, [x + "." + lang for x in
                                                     deps]))
            deps += lang_deps
        return deps

    def is_translation_available(self, lang):
        """Return true if the translation actually exists."""
        return lang in self.translated_to

    def translated_source_path(self, lang):
        """Return path to the translation's source file."""
        if lang in self.translated_to:
            if lang == self.default_lang:
                return self.source_path
            else:
                return '.'.join((self.source_path, lang))
        elif lang != self.default_lang:
            return self.source_path
        else:
            return '.'.join((self.source_path, sorted(self.translated_to)[0]))

    def _translated_file_path(self, lang):
        """Return path to the translation's file, or to the original."""
        if lang in self.translated_to:
            if lang == self.default_lang:
                return self.base_path
            else:
                return '.'.join((self.base_path, lang))
        elif lang != self.default_lang:
            return self.base_path
        else:
            return '.'.join((self.base_path, sorted(self.translated_to)[0]))

    def text(self, lang=None, teaser_only=False, strip_html=False):
        """Read the post file for that language and return its contents."""

        if lang is None:
            lang = self.current_lang()
        file_name = self._translated_file_path(lang)
        with codecs.open(file_name, "r", "utf8") as post_file:
            data = post_file.read().strip()

        try:
            document = lxml.html.document_fromstring(data)
        except lxml.etree.ParserError as e:
            # if we don't catch this, it breaks later (Issue #374)
            if str(e) == "Document is empty":
                return ""
            # let other errors raise
            raise(e)
        document.make_links_absolute(self.permalink(lang=lang))
        data = lxml.html.tostring(document, encoding='unicode')
        if teaser_only:
            teaser = TEASER_REGEXP.split(data)[0]
            if teaser != data:
                teaser_str = self.messages[lang]["Read more"] + '...'
                teaser += '<p><a href="{0}">{1}</a></p>'.format(
                    self.permalink(lang), teaser_str)
                # This closes all open tags and sanitizes the broken HTML
                document = lxml.html.fromstring(teaser)
                data = lxml.html.tostring(document, encoding='unicode')

        if data and strip_html:
            content = lxml.html.fromstring(data)
            data = content.text_content().strip()  # No whitespace wanted.
        return data

    def destination_path(self, lang, extension='.html'):
        path = os.path.join(self.translations[lang],
                            self.folder, self.meta[lang]['slug'] + extension)
        return path

    def permalink(self, lang=None, absolute=False, extension='.html'):
        if lang is None:
            lang = self.current_lang()

        pieces = self.translations[lang].split(os.sep)
        pieces += self.folder.split(os.sep)
        pieces += [self.meta[lang]['slug'] + extension]
        pieces = [_f for _f in pieces if _f and _f != '.']
        if absolute:
            pieces = [self.base_url] + pieces
        else:
            pieces = [""] + pieces
        link = "/".join(pieces)
        if self.strip_index_html and link.endswith('/index.html'):
            return link[:-10]
        else:
            return link

    def source_ext(self):
        return os.path.splitext(self.source_path)[1]

# Code that fetches metadata from different places


def re_meta(line, match=None):
    """re.compile for meta"""
    if match:
        reStr = re.compile('^\.\. {0}: (.*)'.format(re.escape(match)))
    else:
        reStr = re.compile('^\.\. (.*?): (.*)')
    result = reStr.findall(line.strip())
    if match and result:
        return (match, result[0])
    elif not match and result:
        return (result[0][0], result[0][1].strip())
    else:
        return (None,)


def _get_metadata_from_filename_by_regex(filename, metadata_regexp):
    """
    Tries to ried the metadata from the filename based on the given re.
    This requires to use symbolic group names in the pattern.

    The part to read the metadata from the filename based on a regular
    expression is taken from Pelican - pelican/readers.py
    """
    match = re.match(metadata_regexp, filename)
    meta = {}

    if match:
        # .items() for py3k compat.
        for key, value in match.groupdict().items():
            meta[key.lower()] = value  # metadata must be lowercase

    return meta


def get_metadata_from_file(source_path, lang=None):
    """Extracts metadata from the file itself, by parsing contents."""
    try:
        if lang:
            source_path = "{0}.{1}".format(source_path, lang)
        with codecs.open(source_path, "r", "utf8") as meta_file:
            meta_data = [x.strip() for x in meta_file.readlines()]
        return _get_metadata_from_file(meta_data)
    except Exception:  # The file may not exist, for multilingual sites
        return {}


def _get_metadata_from_file(meta_data):
    """Parse file contents and obtain metadata.

    >>> g = _get_metadata_from_file
    >>> list(g([]).values())
    []
    >>> str(g(["FooBar","======"])["title"])
    'FooBar'
    >>> str(g(["#FooBar"])["title"])
    'FooBar'
    >>> str(g([".. title: FooBar"])["title"])
    'FooBar'
    >>> 'title' in g(["",".. title: FooBar"])
    False

    """
    meta = {}

    re_md_title = re.compile(r'^{0}([^{0}].*)'.format(re.escape('#')))
    # Assuming rst titles are going to be at least 4 chars long
    # otherwise this detects things like ''' wich breaks other markups.
    re_rst_title = re.compile(r'^([{0}]{{4,}})'.format(re.escape(
        string.punctuation)))

    for i, line in enumerate(meta_data):
        if not line:
            break
        if 'title' not in meta:
            match = re_meta(line, 'title')
            if match[0]:
                meta['title'] = match[1]
        if 'title' not in meta:
            if re_rst_title.findall(line) and i > 0:
                meta['title'] = meta_data[i - 1].strip()
        if 'title' not in meta:
            if re_md_title.findall(line):
                meta['title'] = re_md_title.findall(line)[0]

        match = re_meta(line)
        if match[0]:
            meta[match[0]] = match[1]

    return meta


def get_metadata_from_meta_file(path, lang=None):
    """Takes a post path, and gets data from a matching .meta file."""
    meta_path = os.path.splitext(path)[0] + '.meta'
    if lang:
        meta_path += '.' + lang
    if os.path.isfile(meta_path):
        with codecs.open(meta_path, "r", "utf8") as meta_file:
            meta_data = meta_file.readlines()
        while len(meta_data) < 6:
            meta_data.append("")
        (title, slug, date, tags, link, description) = [
            x.strip() for x in meta_data][:6]

        meta = {}

        if title:
            meta['title'] = title
        if slug:
            meta['slug'] = slug
        if date:
            meta['date'] = date
        if tags:
            meta['tags'] = tags
        if link:
            meta['link'] = link
        if description:
            meta['description'] = description

        return meta
    else:
        return {}


def get_meta(post, file_metadata_regexp=None, lang=None):
    """Get post's meta from source.

    If ``file_metadata_regexp`` is given it will be tried to read
    metadata from the filename.
    If any metadata is then found inside the file the metadata from the
    file will override previous findings.
    """
    meta = defaultdict(lambda: '')

    meta.update(get_metadata_from_meta_file(post.metadata_path, lang))

    if meta:
        return meta

    if file_metadata_regexp is not None:
        meta.update(_get_metadata_from_filename_by_regex(post.source_path,
                                                         file_metadata_regexp))

    meta.update(get_metadata_from_file(post.source_path, lang))

    if lang is None:
        # Only perform these checks for the default language

        if 'slug' not in meta:
            # If no slug is found in the metadata use the filename
            meta['slug'] = slugify(os.path.splitext(
                os.path.basename(post.source_path))[0])

        if 'title' not in meta:
            # If no title is found, use the filename without extension
            meta['title'] = os.path.splitext(
                os.path.basename(post.source_path))[0]

    return meta