# Python 2.3 ... 2.6 compatibility:
from roundup.anypy.sets_ import set

# Roles that can always remove or restore files and messages
EDIT_ROLES = set('Developer Admin Coordinator'.split())

def removed(db, cl, nodeid, newvalues, name):
    ''' Sets [msg|file].issueid on unlink, unsets on link

    Used for restoring removed files or messages in the web UI.
    Also audits spurious removals and restorations by users.
    '''
    if name == 'messages':
        klass = db.msg
    elif name == 'files':
        klass = db.file
    new = set(newvalues[name] or [])
    old = set(cl.get(nodeid, name) or [])
    len_new, len_old = len(new), len(old)
    if len_new != len_old:
        user = db.getuid()
        roles = db.user.get(user, 'roles').split(',')
        add_remove_ok = bool([role for role in roles if role in EDIT_ROLES])
        if len_new < len_old:
            gone = (old - new).pop()
            if name == 'files':
                # Allow users to remove their own files
                file_creator = klass.get(gone, 'creator') == user
                add_remove_ok = add_remove_ok or file_creator
            if add_remove_ok:
                # Record issue id in removed file/msg
                klass.set(gone, issueid=nodeid)
            else:
                raise ValueError(
                                 "You don't have permission to remove %s %s."
                                 % (name[:-1], gone))
        else:
            added = (new - old).pop()
            # Allow adding new files and messages that were
            # not previously unlinked
            add_remove_ok = add_remove_ok or not klass.get(added, 'issueid')
            if add_remove_ok:
                if klass.get(added, 'issueid') == nodeid:
                    klass.set(added, issueid='')
            else:
                raise ValueError(
                                 "You don't have permission to remove %s %s."
                                 % (name[:-1], added))

def removed_file(db, cl, nodeid, newvalues):
    if 'files' not in newvalues or nodeid is None:
        return
    removed(db, cl, nodeid, newvalues, 'files')

def removed_msg(db, cl, nodeid, newvalues):
    if 'messages' not in newvalues or nodeid is None:
        return
    removed(db, cl, nodeid, newvalues, 'messages')


def init(db):
    db.issue.audit('set', removed_msg)
    db.issue.audit('set', removed_file)