#!/usr/bin/python -u
# vim: set fileencoding=utf-8 :
#
# (C) 2008 Guido Guenther <agx@sigxcpu.org>
#    This program is free software; you can redistribute it and/or modify
#    it under the terms of the GNU General Public License as published by
#    the Free Software Foundation; either version 2 of the License, or
#    (at your option) any later version.
#
#    This program is distributed in the hope that it will be useful,
#    but WITHOUT ANY WARRANTY; without even the implied warranty of
#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#    GNU General Public License for more details.
#
#    You should have received a copy of the GNU General Public License
#    along with this program; if not, write to the Free Software
#    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
#
"""Link Debian changelog entries to the VCS"""

import cgi
import os
import re
import sys
import urlgrabber
from lxml import etree
from genshi.template import TemplateLoader
import vcsbrowsers
from htmlchangelog import HTMLChangelog

VERSION="0.0.3"
XMLNS='http://www.w3.org/1999/xhtml'
PTS='http://packages.qa.debian.org'
PKGNAMERE="[a-zA-Z0-9.+\-]+$"


def fetch_changelog(cl_url):
    changelog = urlgrabber.urlread(cl_url, timeout=5.0).decode('utf-8')
    return changelog


def fetch_pts_page(package):
    pts = None
    try:
        url = "%s/%s" % (PTS, package)
        pts = urlgrabber.urlopen(url, timeout=5.0)
    except urlgrabber.grabber.URLGrabError as (code, msg):
        if code == 14:
            raise Exception, "Can't find package '%s' on '%s'" % (package, PTS)
        else:
            raise
    return pts


def parse_pts_xhtml(pts):
    cl_url = None
    vcs_url = None
    vcs = None

    tree = etree.parse(pts)
    searcher = etree.ETXPath('/{%s}html/{%s}body//{%s}a[@href]' % (XMLNS, XMLNS, XMLNS))
    result = searcher(tree)

    for r in result:
        if not r.text:
            continue
        if r.text.lower() == "changelog":
            cl_url = r.attrib['href']
        elif r.text.lower() == "browse":
            vcs_url = r.attrib['href']
            parent = r.getparent()
            vcs = parent.getchildren()[0].text.lower()
    return cl_url, vcs_url, vcs


def get_vcsbrowser(vcs, vcs_url):
    if vcs == "git":
        return vcsbrowsers.GitWebBrowser(vcs_url)
    elif vcs == "Mercurial":
        return vcsbrowsers.HgBrowser(vcs_url)


def render_search_page(title, pkg=None, err=None):
    loader = TemplateLoader('templates')
    tmpl = loader.load('index.html')
    print tmpl.generate(title=title, pkg=pkg,
                        err=err).render('xhtml', doctype='xhtml-strict')


def render_changelog_page(cl):
    print cl


def main(argv):
    title = "cl2vcs %s" % VERSION
    err = ""

    print "Content-Type: text/html; charset=utf-8"
    print

    try:
        form = cgi.FieldStorage()

        if form.has_key('pkg'):
            pkg = form.getfirst('pkg').decode('utf-8').strip()
        else:
            pkg = None

        if pkg:
            if not re.match(PKGNAMERE, pkg):
                return render_search_page(title=title, err=u"Invalid package name: '%s'" % pkg)
            else:
                pkg = str(pkg)
        else:
            return render_search_page(title=title, err=err)

        try:
            pts = fetch_pts_page(pkg)
        except Exception as exc_err:
            err = exc_err
            pts = None

        if not pts:
            return render_search_page(title=title, pkg=pkg, err=err)

        cl_url, vcs_url, vcs = parse_pts_xhtml(pts)
        if cl_url == None:
            return render_search_page(title=title, pkg=pkg,
                                      err="Cannot parse changelog from PTS page.")
        try:
            cl_text = fetch_changelog(cl_url)
        except urlgrabber.grabber.URLGrabError, (errcode, errmsg):
            return render_search_page(title=title,
                                      err="Cannot fetch '%s': %s" % (cl_url, errmsg))
        if vcs and vcs_url:
            vcsbrowser = get_vcsbrowser(vcs, vcs_url)
        else:
            vcsbrowser = None
        cl = HTMLChangelog(cl_text, vcsbrowser=vcsbrowser)
        if cl:
            render_changelog_page(cl)
    except Exception, err:
        import traceback
        traceback.print_exc(file=sys.stderr)
        render_search_page(title=title, err="Unknown error")
    return 0

if __name__ == "__main__":
    sys.exit(main(sys.argv))