""" Invoke an external command to verify file contents """

import os
import sys
import shlex
from Bcfg2.Server.Plugin import PluginExecutionError
from subprocess import Popen, PIPE
from Bcfg2.Server.Plugins.Cfg import CfgVerifier, CfgVerificationError


class CfgExternalCommandVerifier(CfgVerifier):
    """ Invoke an external script to verify
    :ref:`server-plugins-generators-cfg` file contents """

    #: Handle :file:`:test` files
    __basenames__ = [':test']

    def __init__(self, name, specific, encoding):
        CfgVerifier.__init__(self, name, specific, encoding)
        self.cmd = []
    __init__.__doc__ = CfgVerifier.__init__.__doc__

    def verify_entry(self, entry, metadata, data):
        try:
            proc = Popen(self.cmd, stdin=PIPE, stdout=PIPE, stderr=PIPE)
            err = proc.communicate(input=data)[1]
            rv = proc.wait()
            if rv != 0:
                raise CfgVerificationError(err)
        except:
            err = sys.exc_info()[1]
            raise CfgVerificationError("Error running external command "
                                       "verifier: %s" % err)
    verify_entry.__doc__ = CfgVerifier.verify_entry.__doc__

    def handle_event(self, event):
        CfgVerifier.handle_event(self, event)
        if not self.data:
            return
        self.cmd = []
        if not os.access(self.name, os.X_OK):
            bangpath = self.data.splitlines()[0].strip()
            if bangpath.startswith("#!"):
                self.cmd.extend(shlex.split(bangpath[2:].strip()))
            else:
                raise PluginExecutionError("Cannot execute %s" % self.name)
        self.cmd.append(self.name)
    handle_event.__doc__ = CfgVerifier.handle_event.__doc__