# Copyright 2008 LShift Ltd
# Copyright 2006 Vadim Gelfer <vadim.gelfer@gmail.com>
#
# Authors:
# Paul Crowley <paul@lshift.net>
# Vadim Gelfer <vadim.gelfer@gmail.com>
#
# This software may be used and distributed according to the terms
# of the GNU General Public License, incorporated herein by reference.

from mercurial.i18n import _
from mercurial.node import *
from mercurial import util

import os
import ruleset

class Checker(object):
    '''acl checker.'''

    def __init__(self, ui, repo):
        self.ui = ui
        self.repo = repo
        
        self.rules = ruleset.rules_from_env()
        self.rules.set(user = os.environ['REMOTE_USER'])
        self.rules.set(repo = os.environ['HG_REPO_PATH'])

    def allow(self, node):
        '''return if access allowed, raise exception if not.'''
        ctx = self.repo.changectx(node)
        branch = ctx.branch()
        if not self.rules.allow("write", branch=branch, file=None):
            return False
        for f in ctx.files():
            if not self.rules.allow("write", branch=branch, file=f):
                return False
        self.ui.debug(_('%s: allowing changeset %s\n') % (__name__, short(node)))
        return True

    def check(self, node):
        if not self.allow(node):
            raise util.Abort(_('%s: access denied for changeset %s') %
                (__name__, short(node)))

        
def hook(ui, repo, hooktype, node=None, source=None, **kwargs):
    if hooktype != 'pretxnchangegroup':
        raise util.Abort(_('config error - hook type "%s" cannot stop '
                           'incoming changesets') % hooktype)
    c = Checker(ui, repo)
    start = repo.changelog.rev(bin(node))
    end = repo.changelog.count()
    for rev in xrange(start, end):
        c.check(repo.changelog.node(rev))