"""Copia uma arvore do SVN do SourceForge pelas listagens HTML do mod_dav_svn (sem cliente svn), para
montar o fonte do pak64 numa revisao fixa (build-simutrans.sh).
uso: python3 -I svnexport.py 'https://svn.code.sf.net/p/simutrans/code/!svn/bc/<rev>/pak64/' <pasta>"""
import concurrent.futures as cf, os, re, sys, urllib.parse, urllib.request

base, out = sys.argv[1], sys.argv[2]
files = []


def walk(rel):
    html = urllib.request.urlopen(base + rel).read().decode('utf-8')
    for href in re.findall(r'<li><a href="([^"]+)">', html):
        if href == '../':
            continue
        if href.endswith('/'):
            walk(rel + href)
        else:
            files.append(rel + href)


def get(rel):
    path = os.path.join(out, urllib.parse.unquote(rel))
    os.makedirs(os.path.dirname(path), exist_ok=True)
    for attempt in range(4):
        try:
            data = urllib.request.urlopen(base + rel).read()
            break
        except OSError:
            if attempt == 3:
                raise
    with open(path, 'wb') as f:
        f.write(data)


walk('')
with cf.ThreadPoolExecutor(8) as ex:
    list(ex.map(get, files))
print(len(files), 'files')