#!/usr/bin/python
# -*- coding: utf-8 -*-
"""A super-minimal but hopefully reliable Wiki server in Python.
"""

import socket, thread, sys, cgi, pickle, os, errno, urlparse, email.parser, re

def main(fname, port):
    docs = pickle.load(open(fname)) if os.path.exists(fname) else {}
    s = socket.socket()
    s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1) # avoid errno 98
    s.bind(('', port))
    s.listen(5)

    lock = thread.allocate_lock()
    while True: thread.start_new_thread(serve, (fname, docs, lock, s.accept()))

def serve(fname, docs, lock, (c, _)):
    f = c.makefile()
    method, path = f.readline().split()[:2] # XXX this is failing!

    with lock: old = docs.get(path)
    edit_form = ("<form method=POST><input type=submit><textarea name=e>%s</textarea>"
                 % cgi.escape(old or 'add text here'))

    if method == 'POST':
        form = urlparse.parse_qs(f.read(int(parse(f)['content-length'])))

        with lock:
            old = docs[path] = form['e'][0]
            save(docs, fname)

    c.send(ok + "page doesn’t yet exist" + edit_form if old is None else
           ok + '<h1>%s</h1>' % cgi.escape(path[1:]) + render(old) + edit_form)

css = "<style>textarea { min-height: 20em; display: block }\n</style>"
ok = "HTTP/1.0 200 OK\r\nContent-type: text/html; charset=utf-8\r\n\r\n" + css

def render(wikitext):
    return (re.compile(r'\[\[([\s\w]+)\]\]').sub(link, cgi.escape(wikitext))
            .replace('\r\n', '\n').replace('\n\n', '<p>'))

def link(mo):
    n = cgi.escape(mo.group(1))
    return '<a href="%s">%s</a>' % (n, n) # n_n

def save(docs, fname):
    with open(fname + ".new", "w") as out:
        pickle.dump(docs, out)
        out.flush()
        os.fsync(out.fileno())
    os.rename(fname + ".new", fname)

def parse(fp):
    header = []
    for line in fp:
        if not line.strip():
            return email.parser.Parser().parsestr(''.join(header))
        header.append(line)

if __name__ == '__main__':
    main(sys.argv[1] if sys.argv[1:] else 'attowiki.pck',
         int(sys.argv[2]) if sys.argv[2:] else 8080)