import os
import re
import glob
import html
import email
import logging
import datetime
from multiprocessing import Pool
from string import Template

import markdown
from markdown.extensions.toc import TocExtension

destpath_re = re.compile(r'\.md$')
logging.basicConfig(encoding='utf-8', level=logging.INFO)

cpu_count = os.cpu_count()

def convert(text):
	md = markdown.Markdown(extensions=['extra', 'meta', TocExtension(anchorlink=True)])
	res = md.convert(text)
	return res, md.Meta

def render_post(fpath):
	destpath = destpath_re.sub('.html', fpath)
	logging.info("opening %s for parsing, dest %s", fpath, destpath)
	# from: https://python-markdown.github.io/reference/
	with open(fpath, "r", encoding="utf-8") as input_file:
		logging.info("reading %s", fpath)
		text = input_file.read()

	logging.info("parsing %s", fpath)
	out, meta = convert(text)

	title = meta.get('title')[0]
	date = meta.get('date')[0]
	draft = False
	if meta.get('draft'):
		draft = True

	title_out, _ = convert('# ' + title)
	out = title_out + out

	logging.info("writing to %s", destpath)
	render_template('index.html.tmpl', destpath, {'content': out, 'more_title': ' - ' + title})

	return {
		'title': title,
		'date': date,
		'fpath': fpath,
		'destpath': destpath,
		'draft': draft,
	}

def render_posts():
	files = glob.glob('posts/*.md')
	logging.info('found post files %s', files)
	posts = []
	logging.info('starting render posts with cpu_count: %d', cpu_count)
	with Pool(processes=cpu_count) as pool:
		posts = pool.map(render_post, files)

	logging.info("render_posts result: %s", posts)
	return posts

def posts_list_html(posts):
	post_tpl = """<li>
		<a href="{href}">{title}</a>
		<time datetime="{date}">{disp_date}</time>
	</li>"""
	out = '<ul class="blog-posts-list">'
	for post in posts:
		disp_date = datetime.datetime.fromisoformat(post.get('date')).strftime('%Y-%m-%d')
		out += post_tpl.format(href=post.get('destpath'),
						 title=post.get('title'),
						 date=post.get('date'),
						 disp_date=disp_date)
	return out + '</ul>'

def render_template(tpl_fname, out_fname, subs):
	with open(tpl_fname, 'r', encoding='utf-8') as inf:
		tmpl = Template(inf.read())

	out = tmpl.substitute(subs)

	with open(out_fname, 'w', encoding='utf-8') as outf:
		outf.write(out)

def render_index(posts):
	content_html = posts_list_html(posts)
	render_template('index.html.tmpl', 'index.html', {'content': content_html, 'more_title': ''})

def rss_post_xml(post):
	tpl = """
	<item>
		<title>{title}</title>
		<link>{link}</link>
		<pubDate>{pubdate}</pubDate>
		<guid>{link}</guid>
		<description>{description}</description>
	</item>
	"""
	link = "https://cfebs.com/" + post['destpath']

	with open(post['fpath'], 'r', encoding='utf-8') as inf:
		text = inf.read()


	converted, _ = convert(text)

	pubdate = email.utils.format_datetime(datetime.datetime.fromisoformat(post['date']))
	subs = {
		'title': post['title'],
		'link': link,
		'pubdate': pubdate,
		'description': converted
	 }

	for k,v in subs.items():
		subs[k] = html.escape(v)

	return tpl.format(**subs)

def render_rss_index(posts):
	items = ''
	for post in posts[:5]:
		items += rss_post_xml(post)

	subs = {
		'site_title': 'cfebs.com',
		'site_link': 'https://cfebs.com',
		'self_full_link': 'https://cfebs.com/index.xml',
		'description': 'Recent content from cfebs.com',
		'last_build_date': email.utils.format_datetime(datetime.datetime.now()),
	}
	for k,v in subs.items():
		subs[k] = html.escape(v)

	subs['items'] = items
	render_template('index.xml.tmpl', 'index.xml', subs)

def main():
	posts = render_posts()
	logging.info('rendered posts: %s', posts)
	posts = filter(lambda p: not p['draft'], posts)
	sorted_posts = sorted(posts,
					   key=lambda p: datetime.datetime.fromisoformat(p['date']), reverse=True)
	render_index(sorted_posts)
	render_rss_index(sorted_posts)

if __name__ == '__main__':
	main()