from django import  template #關鍵程式碼
register = template.Library()  #關鍵程式碼
from django.db.models import Count
from django.utils.safestring import mark_safe
from article.models import ArticlePost  

import markdown


#1、返回單個數字
# {% load article_tags %}  必須要有
@register.simple_tag
def total_articles():
    return ArticlePost.objects.count()
#  {% total_articles %}

@register.simple_tag
def author_total_articles(user):
    return user.article.count()
# {% author_total_articles user %}

#2、返回html程式碼
@register.inclusion_tag('article/list/lastest_articles.html')
def latest_articles(n=5):
    lastest_articles = ArticlePost.objects.order_by("-created")[:n]
    return {"latest_articles":lastest_articles}
#   {% latest_articles 4 %}

#3、返回物件陣列
@register.assignment_tag
def most_commented_articles(n=3):
    return ArticlePost.objects.annotate(total_counts = Count('comments')).order_by('-total_comments')[:n]
# {% most_commented_articles as most_comments %}
#  {% for comment_article in most_comments %} #這個是必須的，定義變數。
#  {% endfor %}

#4，自定義過濾器
@register.filter(name='markdown') #重新命名，方便前端呼叫,遵從使用習慣
def markdown_filter(text):  #不能是markdown，與import markdown衝突
    return mark_safe(markdown.markdown(text))
# {% article.boyd | markdown %}