# -*- coding: utf-8 -*-

# Copyright © 2012-2018 Roberto Alsina and others.

# 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
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# the rights to use, copy, modify, merge, publish,
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# 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.
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# WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
# PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS
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"""Render the taxonomy overviews, classification pages and feeds."""

import blinker
import os
import natsort
from collections import defaultdict
from copy import copy
try:
    from urlparse import urljoin
except ImportError:
    from urllib.parse import urljoin  # NOQA

from nikola.plugin_categories import Task
from nikola import utils, hierarchy_utils
from nikola.nikola import _enclosure


class RenderTaxonomies(Task):
    """Render taxonomy pages and feeds."""

    name = "render_taxonomies"

    def _generate_classification_overview_kw_context(self, taxonomy, lang):
        """Create context and kw for a classification overview page."""
        context, kw = taxonomy.provide_overview_context_and_uptodate(lang)

        context = copy(context)
        context["kind"] = "{}_index".format(taxonomy.classification_name)
        sorted_links = []
        sorted_links_all = []
        for other_lang in sorted(self.site.config['TRANSLATIONS'].keys()):
            sorted_links_all.append((other_lang, None, None))
            if other_lang != lang:
                sorted_links.append((other_lang, None, None))
        context['has_other_languages'] = True
        context['other_languages'] = sorted_links
        context['all_languages'] = sorted_links_all

        kw = copy(kw)
        kw["messages"] = self.site.MESSAGES
        kw["translations"] = self.site.config['TRANSLATIONS']
        kw["filters"] = self.site.config['FILTERS']
        kw["minimum_post_count"] = taxonomy.minimum_post_count_per_classification_in_overview
        kw["output_folder"] = self.site.config['OUTPUT_FOLDER']
        kw["pretty_urls"] = self.site.config['PRETTY_URLS']
        kw["strip_indexes"] = self.site.config['STRIP_INDEXES']
        kw["index_file"] = self.site.config['INDEX_FILE']

        # Collect all relevant classifications
        if taxonomy.has_hierarchy:
            def acceptor(node):
                return len(self._filter_list(self.site.posts_per_classification[taxonomy.classification_name][lang][node.classification_name], lang)) >= kw["minimum_post_count"]

            clipped_root_list = [hierarchy_utils.clone_treenode(node, parent=None, acceptor=acceptor) for node in self.site.hierarchy_per_classification[taxonomy.classification_name][lang]]
            clipped_root_list = [node for node in clipped_root_list if node]
            clipped_flat_hierarchy = hierarchy_utils.flatten_tree_structure(clipped_root_list)

            classifications = [cat.classification_name for cat in clipped_flat_hierarchy]
        else:
            classifications = natsort.natsorted([tag for tag, posts in self.site.posts_per_classification[taxonomy.classification_name][lang].items()
                                                 if len(self._filter_list(posts, lang)) >= kw["minimum_post_count"]],
                                                alg=natsort.ns.F | natsort.ns.IC)
            taxonomy.sort_classifications(classifications, lang)

        # Set up classifications in context
        context[taxonomy.overview_page_variable_name] = classifications
        context["has_hierarchy"] = taxonomy.has_hierarchy
        if taxonomy.overview_page_items_variable_name:
            items = [(classification,
                      self.site.link(taxonomy.classification_name, classification, lang))
                     for classification in classifications]
            items_with_postcount = [
                (classification,
                 self.site.link(taxonomy.classification_name, classification, lang),
                 len(self._filter_list(self.site.posts_per_classification[taxonomy.classification_name][lang][classification], lang)))
                for classification in classifications
            ]
            context[taxonomy.overview_page_items_variable_name] = items
            context[taxonomy.overview_page_items_variable_name + "_with_postcount"] = items_with_postcount
        if taxonomy.has_hierarchy and taxonomy.overview_page_hierarchy_variable_name:
            hier_items = [
                (node.name, node.classification_name, node.classification_path,
                 self.site.link(taxonomy.classification_name, node.classification_name, lang),
                 node.indent_levels, node.indent_change_before,
                 node.indent_change_after)
                for node in clipped_flat_hierarchy
            ]
            hier_items_with_postcount = [
                (node.name, node.classification_name, node.classification_path,
                 self.site.link(taxonomy.classification_name, node.classification_name, lang),
                 node.indent_levels, node.indent_change_before,
                 node.indent_change_after,
                 len(node.children),
                 len(self._filter_list(self.site.posts_per_classification[taxonomy.classification_name][lang][node.classification_name], lang)))
                for node in clipped_flat_hierarchy
            ]
            context[taxonomy.overview_page_hierarchy_variable_name] = hier_items
            context[taxonomy.overview_page_hierarchy_variable_name + '_with_postcount'] = hier_items_with_postcount
        return context, kw

    def _render_classification_overview(self, classification_name, template, lang, context, kw):
        # Prepare rendering
        context["permalink"] = self.site.link("{}_index".format(classification_name), None, lang)
        if "pagekind" not in context:
            context["pagekind"] = ["list", "tags_page"]
        output_name = os.path.join(self.site.config['OUTPUT_FOLDER'], self.site.path('{}_index'.format(classification_name), None, lang))
        blinker.signal('generate_classification_overview').send({
            'site': self.site,
            'classification_name': classification_name,
            'lang': lang,
            'context': context,
            'kw': kw,
            'output_name': output_name,
        })
        task = self.site.generic_post_list_renderer(
            lang,
            [],
            output_name,
            template,
            kw['filters'],
            context,
        )
        task['uptodate'] = task['uptodate'] + [utils.config_changed(kw, 'nikola.plugins.task.taxonomies:page')]
        task['basename'] = str(self.name)
        yield task

    def _generate_classification_overview(self, taxonomy, lang):
        """Create a global "all your tags/categories" page for a given language."""
        context, kw = self._generate_classification_overview_kw_context(taxonomy, lang)
        for task in self._render_classification_overview(taxonomy.classification_name, taxonomy.template_for_classification_overview, lang, context, kw):
            yield task

    def _generate_tag_and_category_overview(self, tag_taxonomy, category_taxonomy, lang):
        """Create a global "all your tags/categories" page for a given language."""
        # Create individual contexts and kw dicts
        tag_context, tag_kw = self._generate_classification_overview_kw_context(tag_taxonomy, lang)
        cat_context, cat_kw = self._generate_classification_overview_kw_context(category_taxonomy, lang)

        # Combine resp. select dicts
        if tag_context['items'] and cat_context['cat_items']:
            # Combine contexts. We must merge the tag context into the category context
            # so that tag_context['items'] makes it into the result.
            context = cat_context
            context.update(tag_context)
            kw = cat_kw
            kw.update(tag_kw)

            # Update title
            title = self.site.MESSAGES[lang]["Tags and Categories"]
            context['title'] = title
            context['description'] = title
            kw['title'] = title
            kw['description'] = title
        elif cat_context['cat_items']:
            # Use category overview page
            context = cat_context
            kw = cat_kw
        else:
            # Use tag overview page
            context = tag_context
            kw = tag_kw

        # Render result
        for task in self._render_classification_overview('tag', tag_taxonomy.template_for_classification_overview, lang, context, kw):
            yield task

    def _generate_classification_page_as_rss(self, taxonomy, classification, filtered_posts, title, description, kw, lang):
        """Create a RSS feed for a single classification in a given language."""
        kind = taxonomy.classification_name
        # Render RSS
        output_name = os.path.normpath(os.path.join(self.site.config['OUTPUT_FOLDER'], self.site.path(kind + "_rss", classification, lang)))
        feed_url = urljoin(self.site.config['BASE_URL'], self.site.link(kind + "_rss", classification, lang).lstrip('/'))
        deps = []
        deps_uptodate = []
        for post in filtered_posts:
            deps += post.deps(lang)
            deps_uptodate += post.deps_uptodate(lang)
        blog_title = kw["blog_title"](lang)
        task = {
            'basename': str(self.name),
            'name': output_name,
            'file_dep': deps,
            'targets': [output_name],
            'actions': [(utils.generic_rss_renderer,
                        (lang, "{0} ({1})".format(blog_title, title) if blog_title != title else blog_title,
                         kw["site_url"], description, filtered_posts,
                         output_name, kw["feed_teasers"], kw["feed_plain"], kw['feed_length'],
                         feed_url, _enclosure, kw["feed_links_append_query"]))],
            'clean': True,
            'uptodate': [utils.config_changed(kw, 'nikola.plugins.task.taxonomies:rss')] + deps_uptodate,
            'task_dep': ['render_posts'],
        }
        return utils.apply_filters(task, kw['filters'])

    def _generate_classification_page_as_index(self, taxonomy, classification, filtered_posts, context, kw, lang):
        """Render an index page collection using only this classification's posts."""
        kind = taxonomy.classification_name

        def page_link(i, displayed_i, num_pages, force_addition, extension=None):
            return self.site.link(kind, classification, lang, alternative_path=force_addition, page=i)

        def page_path(i, displayed_i, num_pages, force_addition, extension=None):
            return self.site.path(kind, classification, lang, alternative_path=force_addition, page=i)

        context = copy(context)
        context["kind"] = kind
        if "pagekind" not in context:
            context["pagekind"] = ["index", "tag_page"]
        template_name = taxonomy.template_for_single_list

        yield self.site.generic_index_renderer(lang, filtered_posts, context['title'], template_name, context, kw, str(self.name), page_link, page_path)

    def _generate_classification_page_as_atom(self, taxonomy, classification, filtered_posts, context, kw, lang):
        """Generate atom feeds for classification lists."""
        kind = taxonomy.classification_name

        context = copy(context)
        context["kind"] = kind

        yield self.site.generic_atom_renderer(lang, filtered_posts, context, kw, str(self.name), classification, kind)

    def _generate_classification_page_as_list(self, taxonomy, classification, filtered_posts, context, kw, lang):
        """Render a single flat link list with this classification's posts."""
        kind = taxonomy.classification_name
        template_name = taxonomy.template_for_single_list
        output_name = os.path.join(self.site.config['OUTPUT_FOLDER'], self.site.path(kind, classification, lang))
        context["lang"] = lang
        # list.tmpl expects a different format than list_post.tmpl (Issue #2701)
        if template_name == 'list.tmpl':
            context["items"] = [(post.title(lang), post.permalink(lang), None) for post in filtered_posts]
        else:
            context["posts"] = filtered_posts
        if "pagekind" not in context:
            context["pagekind"] = ["list", "tag_page"]
        task = self.site.generic_post_list_renderer(lang, filtered_posts, output_name, template_name, kw['filters'], context)
        task['uptodate'] = task['uptodate'] + [utils.config_changed(kw, 'nikola.plugins.task.taxonomies:list')]
        task['basename'] = str(self.name)
        yield task

    def _filter_list(self, post_list, lang):
        """Return only the posts which should be shown for this language."""
        if self.site.config["SHOW_UNTRANSLATED_POSTS"]:
            return post_list
        else:
            return [x for x in post_list if x.is_translation_available(lang)]

    def _generate_subclassification_page(self, taxonomy, node, context, kw, lang):
        """Render a list of subclassifications."""
        def get_subnode_data(subnode):
            return [
                taxonomy.get_classification_friendly_name(subnode.classification_name, lang, only_last_component=True),
                self.site.link(taxonomy.classification_name, subnode.classification_name, lang),
                len(self._filter_list(self.site.posts_per_classification[taxonomy.classification_name][lang][subnode.classification_name], lang))
            ]

        items = [get_subnode_data(subnode) for subnode in node.children]
        context = copy(context)
        context["lang"] = lang
        context["permalink"] = self.site.link(taxonomy.classification_name, node.classification_name, lang)
        if "pagekind" not in context:
            context["pagekind"] = ["list", "archive_page"]
        context["items"] = items
        task = self.site.generic_post_list_renderer(
            lang,
            [],
            os.path.join(kw['output_folder'], self.site.path(taxonomy.classification_name, node.classification_name, lang)),
            taxonomy.subcategories_list_template,
            kw['filters'],
            context,
        )
        task_cfg = {1: kw, 2: items}
        task['uptodate'] = task['uptodate'] + [utils.config_changed(task_cfg, 'nikola.plugins.task.taxonomy')]
        task['basename'] = self.name
        return task

    def _generate_classification_page(self, taxonomy, classification, filtered_posts, generate_list, generate_rss, generate_atom, lang, post_lists_per_lang, classification_set_per_lang=None):
        """Render index or post list and associated feeds per classification."""
        # Should we create this list?
        if not any((generate_list, generate_rss, generate_atom)):
            return
        # Get data
        node = None
        if taxonomy.has_hierarchy:
            node = self.site.hierarchy_lookup_per_classification[taxonomy.classification_name][lang].get(classification)
        context, kw = taxonomy.provide_context_and_uptodate(classification, lang, node)
        kw = copy(kw)
        kw["messages"] = self.site.MESSAGES
        kw["translations"] = self.site.config['TRANSLATIONS']
        kw["filters"] = self.site.config['FILTERS']
        kw["site_url"] = self.site.config['SITE_URL']
        kw["blog_title"] = self.site.config['BLOG_TITLE']
        kw["generate_rss"] = self.site.config['GENERATE_RSS']
        kw["generate_atom"] = self.site.config['GENERATE_ATOM']
        kw["feed_teasers"] = self.site.config["FEED_TEASERS"]
        kw["feed_plain"] = self.site.config["FEED_PLAIN"]
        kw["feed_links_append_query"] = self.site.config["FEED_LINKS_APPEND_QUERY"]
        kw["feed_length"] = self.site.config['FEED_LENGTH']
        kw["output_folder"] = self.site.config['OUTPUT_FOLDER']
        kw["pretty_urls"] = self.site.config['PRETTY_URLS']
        kw["strip_indexes"] = self.site.config['STRIP_INDEXES']
        kw["index_file"] = self.site.config['INDEX_FILE']
        context = copy(context)
        context["permalink"] = self.site.link(taxonomy.classification_name, classification, lang)
        context["kind"] = taxonomy.classification_name
        # Get links to other language versions of this classification
        if classification_set_per_lang is not None:
            other_lang_links = taxonomy.get_other_language_variants(classification, lang, classification_set_per_lang)
            # Collect by language
            links_per_lang = defaultdict(list)
            for other_lang, link in other_lang_links:
                # Make sure we ignore the current language (in case the
                # plugin accidentally returns links for it as well)
                if other_lang != lang:
                    links_per_lang[other_lang].append(link)
            # Sort first by language, then by classification
            sorted_links = []
            sorted_links_all = []
            for other_lang in sorted(list(links_per_lang.keys()) + [lang]):
                if other_lang == lang:
                    sorted_links_all.append((lang, classification, taxonomy.get_classification_friendly_name(classification, lang)))
                else:
                    links = hierarchy_utils.sort_classifications(taxonomy, links_per_lang[other_lang], other_lang)
                    links = [(other_lang, other_classification,
                              taxonomy.get_classification_friendly_name(other_classification, other_lang))
                             for other_classification in links if post_lists_per_lang[other_lang].get(other_classification, ('', False, False))[1]]
                    sorted_links.extend(links)
                    sorted_links_all.extend(links)
            # Store result in context and kw
            context['has_other_languages'] = True
            context['other_languages'] = sorted_links
            context['all_languages'] = sorted_links_all
            kw['other_languages'] = sorted_links
            kw['all_languages'] = sorted_links_all
        else:
            context['has_other_languages'] = False
        # Allow other plugins to modify the result
        blinker.signal('generate_classification_page').send({
            'site': self.site,
            'taxonomy': taxonomy,
            'classification': classification,
            'lang': lang,
            'posts': filtered_posts,
            'context': context,
            'kw': kw,
        })
        # Decide what to do
        if taxonomy.has_hierarchy and taxonomy.show_list_as_subcategories_list:
            # Determine whether there are subcategories
            node = self.site.hierarchy_lookup_per_classification[taxonomy.classification_name][lang][classification]
            # Are there subclassifications?
            if len(node.children) > 0:
                # Yes: create list with subclassifications instead of list of posts
                if generate_list:
                    yield self._generate_subclassification_page(taxonomy, node, context, kw, lang)
                return
        # Generate RSS feed
        if generate_rss and kw["generate_rss"] and not taxonomy.always_disable_rss:
            yield self._generate_classification_page_as_rss(taxonomy, classification, filtered_posts, context['title'], context.get("description"), kw, lang)

        # Generate Atom feed
        if generate_atom and kw["generate_atom"] and not taxonomy.always_disable_atom:
            yield self._generate_classification_page_as_atom(taxonomy, classification, filtered_posts, context, kw, lang)

        # Render HTML
        if generate_list and taxonomy.show_list_as_index:
            yield self._generate_classification_page_as_index(taxonomy, classification, filtered_posts, context, kw, lang)
        elif generate_list:
            yield self._generate_classification_page_as_list(taxonomy, classification, filtered_posts, context, kw, lang)

    def gen_tasks(self):
        """Render the tag pages and feeds."""
        self.site.scan_posts()
        yield self.group_task()

        # Cache classification sets per language for taxonomies where
        # add_other_languages_variable is True.
        classification_set_per_lang = {}
        for taxonomy in self.site.taxonomy_plugins.values():
            if taxonomy.add_other_languages_variable:
                lookup = self.site.posts_per_classification[taxonomy.classification_name]
                cspl = {lang: set(lookup[lang].keys()) for lang in lookup}
                classification_set_per_lang[taxonomy.classification_name] = cspl

        # Collect post lists for classification pages and determine whether
        # they should be generated.
        post_lists_per_lang = {}
        for taxonomy in self.site.taxonomy_plugins.values():
            plpl = {}
            for lang in self.site.config["TRANSLATIONS"]:
                result = {}
                for classification, posts in self.site.posts_per_classification[taxonomy.classification_name][lang].items():
                    # Filter list
                    filtered_posts = self._filter_list(posts, lang)
                    if len(filtered_posts) == 0 and taxonomy.omit_empty_classifications:
                        generate_list = generate_rss = generate_atom = False
                    else:
                        # Should we create this list?
                        generate_list = taxonomy.should_generate_classification_page(classification, filtered_posts, lang)
                        generate_rss = taxonomy.should_generate_rss_for_classification_page(classification, filtered_posts, lang)
                        generate_atom = taxonomy.should_generate_atom_for_classification_page(classification, filtered_posts, lang)
                    result[classification] = (filtered_posts, generate_list, generate_rss, generate_atom)
                plpl[lang] = result
            post_lists_per_lang[taxonomy.classification_name] = plpl

        # Now generate pages
        for lang in self.site.config["TRANSLATIONS"]:
            # To support that tag and category classifications share the same overview,
            # we explicitly detect this case:
            ignore_plugins_for_overview = set()
            if 'tag' in self.site.taxonomy_plugins and 'category' in self.site.taxonomy_plugins and self.site.link("tag_index", None, lang) == self.site.link("category_index", None, lang):
                # Block both plugins from creating overviews
                ignore_plugins_for_overview.add(self.site.taxonomy_plugins['tag'])
                ignore_plugins_for_overview.add(self.site.taxonomy_plugins['category'])
            for taxonomy in self.site.taxonomy_plugins.values():
                if not taxonomy.is_enabled(lang):
                    continue
                # Generate list of classifications (i.e. classification overview)
                if taxonomy not in ignore_plugins_for_overview:
                    if taxonomy.template_for_classification_overview is not None:
                        for task in self._generate_classification_overview(taxonomy, lang):
                            yield task

                # Process classifications
                for classification, (filtered_posts, generate_list, generate_rss, generate_atom) in post_lists_per_lang[taxonomy.classification_name][lang].items():
                    for task in self._generate_classification_page(taxonomy, classification, filtered_posts,
                                                                   generate_list, generate_rss, generate_atom, lang,
                                                                   post_lists_per_lang[taxonomy.classification_name],
                                                                   classification_set_per_lang.get(taxonomy.classification_name)):
                        yield task
            # In case we are ignoring plugins for overview, we must have a collision for
            # tags and categories. Handle this special case with extra code.
            if ignore_plugins_for_overview:
                for task in self._generate_tag_and_category_overview(self.site.taxonomy_plugins['tag'], self.site.taxonomy_plugins['category'], lang):
                    yield task
