#!/usr/bin/env python3
import markdown
import sys
import io
import re
from pygments.formatters import HtmlFormatter
from markdown.extensions.toc import TocExtension
from markdown.extensions import Extension
from markdown.preprocessors import Preprocessor

# Python-Markdown (unlike CommonMark/GitHub) refuses to let a list interrupt a
# paragraph unless there's a blank line between them, so a very common README
# shape renders as one run-on paragraph instead of a list:
#
#     Passing:
#     - foo
#     - bar
#
# This preprocessor restores the GitHub behavior: when a bullet ( - * + ) or a
# "1."/"1)" ordered-list marker immediately follows a paragraph line, insert a
# blank line so the list starts. We deliberately only interrupt on "1" for
# ordered lists (matching CommonMark) so prose like "... the year\n1985. was
# ..." is not turned into a list. Fenced code, indented code, and lines that
# already follow a list item are left untouched.
_MD_FENCE = re.compile(r'^(\s{0,3})(`{3,}|~{3,})')
_MD_BULLET = re.compile(r'^ {0,3}[-*+][ \t]+\S')
_MD_ORDERED1 = re.compile(r'^ {0,3}1[.)][ \t]+\S')
_MD_ANYITEM = re.compile(r'^ {0,3}(?:[-*+]|\d{1,9}[.)])[ \t]')


class _ListInterruptPreprocessor(Preprocessor):
	def run(self, lines):
		out, in_fence, fence = [], False, None
		for line in lines:
			m = _MD_FENCE.match(line)
			if m:
				tok = m.group(2)[0]
				if not in_fence:
					in_fence, fence = True, tok
				elif fence == tok:
					in_fence, fence = False, None
				out.append(line)
				continue
			if not in_fence and out:
				prev = out[-1]
				if (prev.strip() and not _MD_ANYITEM.match(prev)
						and not prev.startswith(('    ', '\t'))
						and (_MD_BULLET.match(line) or _MD_ORDERED1.match(line))):
					out.append('')
			out.append(line)
		return out


class ListInterruptExtension(Extension):
	def extendMarkdown(self, md):
		# priority 21: just above the built-in 'normalize_whitespace' (20) so we
		# operate on clean lines before block parsing.
		md.preprocessors.register(
			_ListInterruptPreprocessor(md), 'list_interrupt', 21)

sys.stdin = io.TextIOWrapper(sys.stdin.buffer, encoding='utf-8')
sys.stdout = io.TextIOWrapper(sys.stdout.buffer, encoding='utf-8')
sys.stdout.write('''
<style>
.markdown-body {
    font-size: 14px;
    line-height: 1.6;
    overflow: hidden;
}
.markdown-body>*:first-child {
    margin-top: 0 !important;
}
.markdown-body>*:last-child {
    margin-bottom: 0 !important;
}
.markdown-body a.absent {
    color: #c00;
}
.markdown-body a.anchor {
    display: block;
    padding-left: 30px;
    margin-left: -30px;
    cursor: pointer;
    position: absolute;
    top: 0;
    left: 0;
    bottom: 0;
}
.markdown-body h1, .markdown-body h2, .markdown-body h3, .markdown-body h4, .markdown-body h5, .markdown-body h6 {
    margin: 20px 0 10px;
    padding: 0;
    font-weight: bold;
    -webkit-font-smoothing: antialiased;
    cursor: text;
    position: relative;
}
.markdown-body h1 .mini-icon-link, .markdown-body h2 .mini-icon-link, .markdown-body h3 .mini-icon-link, .markdown-body h4 .mini-icon-link, .markdown-body h5 .mini-icon-link, .markdown-body h6 .mini-icon-link {
    display: none;
    color: #000;
}
.markdown-body h1:hover a.anchor, .markdown-body h2:hover a.anchor, .markdown-body h3:hover a.anchor, .markdown-body h4:hover a.anchor, .markdown-body h5:hover a.anchor, .markdown-body h6:hover a.anchor {
    text-decoration: none;
    line-height: 1;
    padding-left: 0;
    margin-left: -22px;
    top: 15%;
}
.markdown-body h1:hover a.anchor .mini-icon-link, .markdown-body h2:hover a.anchor .mini-icon-link, .markdown-body h3:hover a.anchor .mini-icon-link, .markdown-body h4:hover a.anchor .mini-icon-link, .markdown-body h5:hover a.anchor .mini-icon-link, .markdown-body h6:hover a.anchor .mini-icon-link {
    display: inline-block;
}
div#cgit .markdown-body h1 a.toclink, div#cgit .markdown-body h2 a.toclink, div#cgit .markdown-body h3 a.toclink, div#cgit .markdown-body h4 a.toclink, div#cgit .markdown-body h5 a.toclink, div#cgit .markdown-body h6 a.toclink {
    color: black;
}
.markdown-body h1 tt, .markdown-body h1 code, .markdown-body h2 tt, .markdown-body h2 code, .markdown-body h3 tt, .markdown-body h3 code, .markdown-body h4 tt, .markdown-body h4 code, .markdown-body h5 tt, .markdown-body h5 code, .markdown-body h6 tt, .markdown-body h6 code {
    font-size: inherit;
}
.markdown-body h1 {
    font-size: 28px;
    color: #000;
}
.markdown-body h2 {
    font-size: 24px;
    border-bottom: 1px solid #ccc;
    color: #000;
}
.markdown-body h3 {
    font-size: 18px;
}
.markdown-body h4 {
    font-size: 16px;
}
.markdown-body h5 {
    font-size: 14px;
}
.markdown-body h6 {
    color: #777;
    font-size: 14px;
}
.markdown-body p, .markdown-body blockquote, .markdown-body ul, .markdown-body ol, .markdown-body dl, .markdown-body table, .markdown-body pre {
    margin: 15px 0;
}
.markdown-body hr {
    border: 2px solid #ccc;
}
.markdown-body>h2:first-child, .markdown-body>h1:first-child, .markdown-body>h1:first-child+h2, .markdown-body>h3:first-child, .markdown-body>h4:first-child, .markdown-body>h5:first-child, .markdown-body>h6:first-child {
    margin-top: 0;
    padding-top: 0;
}
.markdown-body a:first-child h1, .markdown-body a:first-child h2, .markdown-body a:first-child h3, .markdown-body a:first-child h4, .markdown-body a:first-child h5, .markdown-body a:first-child h6 {
    margin-top: 0;
    padding-top: 0;
}
.markdown-body h1+p, .markdown-body h2+p, .markdown-body h3+p, .markdown-body h4+p, .markdown-body h5+p, .markdown-body h6+p {
    margin-top: 0;
}
.markdown-body li p.first {
    display: inline-block;
}
.markdown-body ul, .markdown-body ol {
    padding-left: 30px;
}
.markdown-body ul.no-list, .markdown-body ol.no-list {
    list-style-type: none;
    padding: 0;
}
.markdown-body ul li>:first-child, .markdown-body ul li ul:first-of-type, .markdown-body ul li ol:first-of-type, .markdown-body ol li>:first-child, .markdown-body ol li ul:first-of-type, .markdown-body ol li ol:first-of-type {
    margin-top: 0px;
}
.markdown-body ul li p:last-of-type, .markdown-body ol li p:last-of-type {
    margin-bottom: 0;
}
.markdown-body ul ul, .markdown-body ul ol, .markdown-body ol ol, .markdown-body ol ul {
    margin-bottom: 0;
}
.markdown-body dl {
    padding: 0;
}
.markdown-body dl dt {
    font-size: 14px;
    font-weight: bold;
    font-style: italic;
    padding: 0;
    margin: 15px 0 5px;
}
.markdown-body dl dt:first-child {
    padding: 0;
}
.markdown-body dl dt>:first-child {
    margin-top: 0px;
}
.markdown-body dl dt>:last-child {
    margin-bottom: 0px;
}
.markdown-body dl dd {
    margin: 0 0 15px;
    padding: 0 15px;
}
.markdown-body dl dd>:first-child {
    margin-top: 0px;
}
.markdown-body dl dd>:last-child {
    margin-bottom: 0px;
}
.markdown-body blockquote {
    border-left: 4px solid #DDD;
    padding: 0 15px;
    color: #777;
}
.markdown-body blockquote>:first-child {
    margin-top: 0px;
}
.markdown-body blockquote>:last-child {
    margin-bottom: 0px;
}
.markdown-body table th {
    font-weight: bold;
}
.markdown-body table th, .markdown-body table td {
    border: 1px solid #ccc;
    padding: 6px 13px;
}
.markdown-body table tr {
    border-top: 1px solid #ccc;
    background-color: #fff;
}
.markdown-body table tr:nth-child(2n) {
    background-color: #f8f8f8;
}
.markdown-body img {
    max-width: 100%;
    -moz-box-sizing: border-box;
    box-sizing: border-box;
}
.markdown-body span.frame {
    display: block;
    overflow: hidden;
}
.markdown-body span.frame>span {
    border: 1px solid #ddd;
    display: block;
    float: left;
    overflow: hidden;
    margin: 13px 0 0;
    padding: 7px;
    width: auto;
}
.markdown-body span.frame span img {
    display: block;
    float: left;
}
.markdown-body span.frame span span {
    clear: both;
    color: #333;
    display: block;
    padding: 5px 0 0;
}
.markdown-body span.align-center {
    display: block;
    overflow: hidden;
    clear: both;
}
.markdown-body span.align-center>span {
    display: block;
    overflow: hidden;
    margin: 13px auto 0;
    text-align: center;
}
.markdown-body span.align-center span img {
    margin: 0 auto;
    text-align: center;
}
.markdown-body span.align-right {
    display: block;
    overflow: hidden;
    clear: both;
}
.markdown-body span.align-right>span {
    display: block;
    overflow: hidden;
    margin: 13px 0 0;
    text-align: right;
}
.markdown-body span.align-right span img {
    margin: 0;
    text-align: right;
}
.markdown-body span.float-left {
    display: block;
    margin-right: 13px;
    overflow: hidden;
    float: left;
}
.markdown-body span.float-left span {
    margin: 13px 0 0;
}
.markdown-body span.float-right {
    display: block;
    margin-left: 13px;
    overflow: hidden;
    float: right;
}
.markdown-body span.float-right>span {
    display: block;
    overflow: hidden;
    margin: 13px auto 0;
    text-align: right;
}
.markdown-body code, .markdown-body tt {
    margin: 0 2px;
    padding: 0px 5px;
    border: 1px solid #eaeaea;
    background-color: #f8f8f8;
    border-radius: 3px;
}
.markdown-body code {
    white-space: nowrap;
}
.markdown-body pre>code {
    margin: 0;
    padding: 0;
    white-space: pre;
    border: none;
    background: transparent;
}
.markdown-body .highlight pre, .markdown-body pre {
    background-color: #f8f8f8;
    border: 1px solid #ccc;
    font-size: 13px;
    line-height: 19px;
    overflow: auto;
    padding: 6px 10px;
    border-radius: 3px;
}
.markdown-body pre code, .markdown-body pre tt {
    margin: 0;
    padding: 0;
    background-color: transparent;
    border: none;
}
''')
sys.stdout.write(HtmlFormatter(style='pastie').get_style_defs('.highlight'))
sys.stdout.write('''
</style>   
''')
# Render to a string (not straight to stdout) so we can post-process it.
# Note: you may want to run this through bleach for sanitization
html = markdown.markdown(
	sys.stdin.read(),
	output_format="html5",
	extensions=[
		"markdown.extensions.fenced_code",
		"markdown.extensions.codehilite",
		"markdown.extensions.tables",
		"markdown.extensions.sane_lists",
		ListInterruptExtension(),
		TocExtension(anchorlink=True)],
	extension_configs={
		"markdown.extensions.codehilite":{"css_class":"highlight"}})

# A README's relative paths point at repo content, but a browser resolves them
# against the page the readme is shown on (/<repo>/about/ or the summary page
# /<repo>/), not against the repo root — so they 404. cgit serves blobs only via
# its `plain`/`tree` commands, so rewrite relative references to absolute cgit
# URLs (absolute so it works both on the about page and the summary page):
#   <img src>   -> /<repo>/plain/<path>?h=<branch>   (raw bytes for the browser)
#   <a href>    -> /<repo>/tree/<path>?h=<branch>     (browsable file/dir view)
# Relative hrefs are resolved as paths against the repo root; a href that climbs
# out of the repo with ".." (e.g. ../sibling) is resolved against the repo's URL
# location instead (-> /sibling), matching how sibling repos are addressed.
# cgit exports the repo context to about-filters via these environment vars; if
# they're absent we leave the references untouched.
import os, re
from urllib.parse import urljoin
repo = os.environ.get("CGIT_REPO_URL", "").strip("/")
if repo:
	branch = os.environ.get("CGIT_REPO_DEFBRANCH", "").strip()
	repo_root = "/" + repo + "/"
	plain = repo_root + "plain/"
	query = ("?h=" + branch) if branch else ""
	# leave absolute, protocol-relative, root-relative, anchor, query-only and
	# scheme (mailto:, http:, data:, ...) URLs alone
	skip = re.compile(r"^(?:[a-z][a-z0-9+.\-]*:|//|/|[#?])", re.I)

	def rewrite_img(m):
		url = m.group(2)
		if not url or skip.match(url):
			return m.group(0)
		return m.group(1) + plain + re.sub(r"^\./", "", url) + query + m.group(3)

	def _split_frag(url):
		# split off a trailing #fragment (kept verbatim on the rewritten URL)
		if "#" in url:
			path, frag = url.split("#", 1)
			return path, "#" + frag
		return url, ""

	def _normalize(path):
		# resolve "." / ".." against the repo root; returns (climbs, cleaned)
		# where `climbs` counts ".." segments that escaped above the repo root.
		out, climbs = [], 0
		for seg in path.split("/"):
			if seg in ("", "."):
				continue
			if seg == "..":
				if out:
					out.pop()
				else:
					climbs += 1
			else:
				out.append(seg)
		return climbs, "/".join(out)

	def rewrite_href(m):
		url = m.group(2)
		if not url or skip.match(url):
			return m.group(0)
		path, frag = _split_frag(url)
		climbs, cleaned = _normalize(path)
		if climbs:
			# escapes the repo (sibling repo etc.): resolve against repo location
			dest = urljoin(repo_root, "../" * climbs + cleaned)
		elif cleaned:
			dest = repo_root + "tree/" + cleaned + query
		else:
			dest = repo_root + (query or "")
		return m.group(1) + dest + frag + m.group(3)

	html = re.sub(r'(<img\b[^>]*?\bsrc=")([^"]*)(")', rewrite_img, html, flags=re.I)
	html = re.sub(r'(<a\b[^>]*?\bhref=")([^"]*)(")', rewrite_href, html, flags=re.I)

sys.stdout.write("<div class='markdown-body'>")
sys.stdout.write(html)
sys.stdout.write("</div>")