import ConfigParser
import argparse
import collections
import datetime
import httplib
import json
import logging
import os
import random
import sys
import tempfile
import traceback
import time
import xmlrpclib

import slapos.slap
from slapos.grid.utils import setRunning, setFinished

from erp5.util.taskdistribution import TaskDistributionTool, RPCRetry
from erp5.util.taskdistribution import SAFE_RPC_EXCEPTION_LIST


class AutoSTemp(object):
    """
    Create a self-destructing temporary file.
    Uses mkstemp.
    """
    __unlink = os.unlink

    def __init__(self, value):
        fd, self.__name = tempfile.mkstemp()
        os.write(fd, value)
        os.close(fd)

    @property
    def name(self):
        return self.__name

    def __del__(self):
        self.__unlink(self.__name)

SOFTWARE_STATE_UNKNOWN = -1
SOFTWARE_STATE_INSTALLING = 0
SOFTWARE_STATE_INSTALLED = 1
SOFTWARE_STATE_DESTROYING = 2

INSTANCE_STATE_UNKNOWN = -1
INSTANCE_STATE_STARTING = 0
INSTANCE_STATE_STARTED = 1
INSTANCE_STATE_STOPPING = 2
INSTANCE_STATE_STOPPED = 3
INSTANCE_STATE_DESTROYING = 4

TESTER_STATE_INITIAL = -1
TESTER_STATE_NOTHING = 0
TESTER_STATE_SOFTWARE_INSTALLED = 1
TESTER_STATE_INSTANCE_INSTALLED = 2
TESTER_STATE_INSTANCE_STARTED = 4
TESTER_STATE_INSTANCE_UNINSTALLED = 5



def compute_response_age(created_at):
    # the following does NOT take TZ into account
    created_at = datetime.datetime.strptime(created_at, '%a, %d %b %Y %H:%M:%S %Z')
    gmt_now = datetime.datetime(*time.gmtime()[:6])
    return (gmt_now - created_at).seconds


class x509Transport(xmlrpclib.Transport):
    """
    Similar to xmlrpclib.SecureTransport, but with actually usable x509
    support.
    """
    def __init__(self, x509, *args, **kw):
        xmlrpclib.Transport.__init__(self, *args, **kw)
        self.__x509 = x509

    def make_connection(self, host):
        if not self._connection or host != self._connection[0]:
            try:
                HTTPSConnection = httplib.HTTPSConnection
            except AttributeError:
                raise NotImplementedError("your version of httplib doesn't "
                    "support HTTPS")
            else:
                chost, self._extra_headers, x509 = self.get_host_info((host,
                    self.__x509))
                self._connection = (host, HTTPSConnection(chost, None, **x509))
        return self._connection[1]

class TestTimeout(Exception):
    pass

# Simple decorator to prevent raise due small
# network failures.
def retryOnNetworkFailure(func):
  def wrapper(*args, **kwargs):
    retry_time = 64
    while True:
      try:
        return func(*args, **kwargs)
      except SAFE_RPC_EXCEPTION_LIST, e:
        print 'Network failure: %s , %s' % (sys.exc_info(), e)

      print 'Retry method %s in %i seconds' % (func, retry_time)
      time.sleep(retry_time)
      retry_time += retry_time >> 1

  wrapper.__name__ = func.__name__
  wrapper.__doc__ = func.__doc__
  return wrapper

class SoftwareReleaseTester(RPCRetry):
    deadline = None
    latest_state = None

    def __init__(self,
                name,
                logger,
                master,
                slap_supply, # slapos supply to manage software release
                slap_order, # slapos open order to manage instance
                url, # software release url
                computer_guid, # computer to use for this test run
                max_install_duration,
                max_uninstall_duration,
                request_kw=None, # instance parameters, if instantiation
                    # testing is desired
                max_request_duration=None,
                max_destroy_duration=None,
            ):
        super(SoftwareReleaseTester, self).__init__(master, 16, logger)
        self.name = name
        self.slap_supply = slap_supply
        self.slap_order = slap_order
        self.url = url
        self.computer_guid = computer_guid
        self.request_kw = request_kw
        self.state = TESTER_STATE_INITIAL
        self.transition_dict = {
            # step function
            # delay
            # next_state
            # software_state
            # instance_state
            TESTER_STATE_INITIAL: (
                lambda t: None,
                None,
                TESTER_STATE_NOTHING,
                None,
                None,
            ),
            TESTER_STATE_NOTHING: (
                lambda t: t.install(),
                max_install_duration,
                request_kw is None and TESTER_STATE_INSTANCE_UNINSTALLED or \
                    TESTER_STATE_SOFTWARE_INSTALLED,
                SOFTWARE_STATE_INSTALLED,
                None,
            ),
            TESTER_STATE_SOFTWARE_INSTALLED: (
                lambda t: t.request(),
                max_request_duration,
                TESTER_STATE_INSTANCE_STARTED,
                None,
                INSTANCE_STATE_STARTED,
            ),
            TESTER_STATE_INSTANCE_STARTED: (
                lambda t: t.destroy(),
                max_destroy_duration,
                TESTER_STATE_INSTANCE_UNINSTALLED,
                None,
                INSTANCE_STATE_UNKNOWN,
            ),
            TESTER_STATE_INSTANCE_UNINSTALLED: (
                lambda t: t.uninstall(),
                max_uninstall_duration,
                None,
                None,
                INSTANCE_STATE_UNKNOWN,
            ),
        }

    def __repr__(self):
        deadline = self.deadline
        if deadline is not None:
            deadline -= time.time()
            deadline = '+%is' % (deadline, )
        return '<%s(state=%s, deadline=%s) at %x>' % (
            self.__class__.__name__, self.state, deadline, id(self))

    @retryOnNetworkFailure
    def _supply(self, state):
        self._logger.info('Supply %s@%s: %s', self.url, self.computer_guid,
            state)
        return self.slap_supply.supply(self.url, self.computer_guid, state)

    @retryOnNetworkFailure
    def _request(self, state):
        self._logger.info('Request %s@%s: %s', self.url, self.name, state)
        self.latest_state = state
        return self.slap_order.request(
            software_release=self.url,
            partition_reference=self.name,
            state=state,
            **self.request_kw
        )

    def _getSoftwareState(self):
        # the state of the software release is not reported anymore with the current API.
        return SOFTWARE_STATE_INSTALLED

    def _getInstanceState(self):
        latest_state = self.latest_state
        self._logger.debug('latest_state = %r', latest_state)

        if latest_state is None:
            return INSTANCE_STATE_UNKNOWN
        try:
            requested = self._request(latest_state)
            if requested._computer_id is None:
                return INSTANCE_STATE_UNKNOWN
        except slapos.slap.ServerError:
            self._logger.exception('Got an error requesting partition for '
                'its state')
            return INSTANCE_STATE_UNKNOWN

        try:
            instance_state = requested.getStatus()
            if instance_state['text'].startswith('#error'):
                return INSTANCE_STATE_UNKNOWN

            server_response_age = compute_response_age(instance_state['created_at'])
            self._logger.debug('Created at: %s (%d secs ago)' % (instance_state['created_at'], server_response_age))

            if instance_state['text'].startswith('#access') and server_response_age < 60*5:
                return INSTANCE_STATE_STARTED
        except slapos.slap.ResourceNotReady:
            return INSTANCE_STATE_UNKNOWN

        return INSTANCE_STATE_UNKNOWN

    def install(self):
        """
        Make software available on computer.
        """
        self._supply('available')

    def uninstall(self):
        """
        Make software unavailable on computer.
        """
        self._supply('destroyed')

    def start(self):
        """
        Request started instance (or starting existing one)
        """
        self._request('started')
    request = start

    def stop(self):
        """
        Request stopped instance (or stopping existing one).
        """
        self._request('stopped')

    def destroy(self):
        """
        Destroy existing instance.
        """
        self._request('destroyed')

    def teardown(self):
        """
        Interrupt a running test sequence, putting it in idle state.
        """
        self._logger.info('Invoking TearDown for %s@%s' % (self.url, self.name))
        if self.request_kw is not None:
            self.destroy()
        self.uninstall()
        self.state = TESTER_STATE_INSTANCE_UNINSTALLED

    def tic(self, now):
        """
        Check for missed deadlines (-> test failure), conditions for moving to
        next state, and actually moving to next state (executing its payload).
        """
        self._logger.debug('TIC')
        deadline = self.deadline
        if deadline < now and deadline is not None:
            raise TestTimeout(self.state)
        _, _, next_state, software_state, instance_state = self.transition_dict[
            self.state]

        if (software_state is None or
                software_state == self._getSoftwareState()) and (
                instance_state is None or
                instance_state == self._getInstanceState()):
            self._logger.debug('Going to state %s (%r, %r)', next_state,
                software_state, instance_state)
            if next_state is None:
                return None
            self.state = next_state
            stepfunc, delay, _, _, _ = self.transition_dict[next_state]
            self.deadline = now + delay
            stepfunc(self)
        return self.deadline


class TestMap(object):
   def __init__(self, test_dict):
       self.test_map_dict = collections.OrderedDict()
       for key in test_dict:
           target_computer = test_dict[key]["target_computer"]
           if target_computer not in self.test_map_dict:
               self.test_map_dict[target_computer] = [key]
           else:
               self.test_map_dict[target_computer].append(key)

   def getExcludeList(self, computer_id):
       exclude_list = []
       for key in self.test_map_dict:
           if key != computer_id:
               exclude_list.extend(self.test_map_dict[key])
       return set(exclude_list)

   def getComputerList(self):
       return self.test_map_dict.keys()

   def dropComputer(self, computer_id):
       del self.test_map_dict[computer_id]

   def cleanUp(self):
       for key in self.test_map_dict.copy():
          if len(self.test_map_dict[key]) == 0:
              del self.test_map_dict[key]

   def getNextComputer(self, used_computer_list):
       for computer in self.getComputerList():
           if computer not in used_computer_list:
               return computer

       return None

def main():
    """
    Note: This code does not test as much as it monitors.
    The goal is to regularily try to build & instantiate a software release
    on several machines, to monitor vifib stability and SR stability as time
    passes (and things once available online become unavailable).
    Part of this function could be reused to make an actual test bot, testing
    only when actual changes are committed to a software release, to look for
    regressions.

    Note: This code does not connect to any instantiated service, it relies on
    the presence of a promise section to make instantiation fail until promise
    is happy.
    """
    parser = argparse.ArgumentParser()
    parser.add_argument('--pidfile', '-p', help='pidfile preventing parallel '
        'execution.')
    parser.add_argument('--log', '-l', help='Log file path.')
    parser.add_argument('--verbose', '-v', help='Be verbose.',
        action='store_true')
    parser.add_argument('configuration_file', type=argparse.FileType(),
        help='Slap Test Agent configuration file.')
    # Just to keep strong references to AutoSTemp instances
    key_file_dict = {}
    def asFilenamePair(key, cert):
        # Note: python's ssl support only supports fetching key & cert data
        # from on-disk files. This is why we need to "convert" direct data
        # into file paths, using temporary files.
        cert = cert.strip()
        try:
            temp_key, temp_cert = key_file_dict[cert]
        except KeyError:
            temp_key = AutoSTemp(key.strip())
            temp_cert = AutoSTemp(cert)
            key_file_dict[cert] = (temp_key, temp_cert)
        return temp_key.name, temp_cert.name
    args = parser.parse_args()

    log = args.log
    formatter = logging.Formatter('%(asctime)s %(message)s')
    logger = logging.getLogger()
    if args.verbose:
        log_level = logging.DEBUG
    else:
        log_level = logging.INFO
    logger.setLevel(log_level)
    handler = logging.StreamHandler(sys.stdout)
    handler.setFormatter(formatter)
    logger.addHandler(handler)
    if log:
        handler = logging.FileHandler(log)
        handler.setFormatter(formatter)
        logger.addHandler(handler)
        log_file = open(log)
        log_file.seek(0, 2)

    pidfile = args.pidfile
    if pidfile:
        setRunning(pidfile)
    try:
        section_dict = collections.OrderedDict()
        configuration = ConfigParser.SafeConfigParser()
        configuration.readfp(args.configuration_file)
        for section in configuration.sections():
            if section == 'agent':
                continue
            section_dict[section] = section_entry_dict = dict(
                configuration.items(section))
            for key in ('request_kw', 'max_install_duration',
                        'max_destroy_duration', 'max_request_duration',
                        'max_uninstall_duration', 'computer_list'
                    ):
                if key in section_entry_dict:
                    try:
                        if isinstance(section_entry_dict[key], str) or \
                              isinstance(section_entry_dict[key], unicode):
                            section_entry_dict[key] = json.loads(
                                                  section_entry_dict[key])
                    except Exception as exc:
                        logger.error("Fail to load %s on %s" % (key, section_entry_dict))
                        raise
            if 'key' in section_entry_dict:
                key_file, cert_file = asFilenamePair(section_entry_dict['key'],
                    section_entry_dict['cert'])
                section_entry_dict['key'] = key_file
                section_entry_dict['cert'] = cert_file
            if "computer_list" in section_entry_dict:
                section_entry_dict["target_computer"] = \
                          random.choice(section_entry_dict["computer_list"])
        agent_parameter_dict = dict(configuration.items('agent'))
        # XXX: should node title be auto-generated by installation recipe ?
        # For example, using computer guid.
        node_title = agent_parameter_dict['node_title']
        test_title = agent_parameter_dict['test_title']
        project_title = agent_parameter_dict['project_title']
        task_distribution_tool = TaskDistributionTool(agent_parameter_dict[
            'report_url'])
        master_slap_connection_dict = {}
        test_result = task_distribution_tool.createTestResult(
            revision='',
            test_name_list=section_dict.keys(),
            node_title=node_title,
            allow_restart=True,
            test_title=test_title,
            project_title=project_title,
        )
        assert test_result is not None
        test_result.watcher_period = 300
        if log:
            test_result.addWatch(log, log_file, max_history_bytes=10000)
        test_mapping = TestMap(section_dict)
        logger.info("Running %d tests in parallel." % \
                      len(test_mapping.getComputerList()))

        ran_test_set = set()
        running_test_dict = collections.OrderedDict()
        more_tests = True
        logger.info('Starting Test Agent run %s ' % node_title)
        while True:
            # Get up to parallel_task_count tasks to execute
            while len(running_test_dict) < len(test_mapping.getComputerList())\
                    and more_tests:
                test_mapping.cleanUp()
                target_computer = test_mapping.getNextComputer([computer \
                        for _, _, computer in running_test_dict.itervalues()])

                test_line = test_result.start(
                    exclude_list= list(ran_test_set) + \
                           list(test_mapping.getExcludeList(target_computer)))

                logger.info("Test Line: %s " % test_line)
                logger.info("Ran Test Set: %s " % ran_test_set)
                logger.info("Running test dict: %s " % running_test_dict)
                logger.info("Target Computer: %s " % target_computer)
                if test_line is None:
                    test_mapping.dropComputer(target_computer)
                    if len(test_mapping.getComputerList()) == 0:
                        more_tests = False
                    continue
                test_name = test_line.name
                try:
                    section_entry_dict = section_dict[test_name]
                except KeyError:
                    # We don't know how to execute this test. Assume it doesn't
                    # exist anymore, and fail it in result.
                    test_line.stop(stderr='This test does not exist on test '
                        'node %s' % (node_title, ))
                    continue
                master_url = section_entry_dict['master_url']
                master_slap_connection_key = (master_url,
                    section_entry_dict.get('key'))
                try:
                    supply, order, rpc = master_slap_connection_dict[
                        master_slap_connection_key]
                except KeyError:
                    key = section_entry_dict.get('key')
                    cert = section_entry_dict.get('cert')
                    slap = slapos.slap.slap()
                    slap.initializeConnection(master_url, key, cert)
                    supply = slap.registerSupply()
                    order = slap.registerOpenOrder()
                    assert master_url.startswith('https:')
                    rpc = xmlrpclib.ServerProxy(master_url, allow_none=True,
                        transport=x509Transport(
                            {'key_file': key, 'cert_file': cert}))
                    master_slap_connection_dict[
                        master_slap_connection_key] = (supply, order, rpc)
                tester = SoftwareReleaseTester(
                    test_name + '_' + node_title + time.strftime(
                        '_%Y/%m/%d_%H:%M:%S_+0000', time.gmtime()),
                    logger,
                    rpc,
                    supply,
                    order,
                    section_entry_dict['url'],
                    section_entry_dict['target_computer'],
                    section_entry_dict['max_install_duration'],
                    section_entry_dict['max_uninstall_duration'],
                    section_entry_dict.get('request_kw'),
                    section_entry_dict.get('max_request_duration'),
                    section_entry_dict.get('max_destroy_duration'),
                )
                ran_test_set.add(test_name)
                running_test_dict[test_name] = (test_line, tester, target_computer)
            if not running_test_dict:
               break

            now = time.time()
            # Synchronise refreshes on watcher period, so it doesn't report a
            # stalled test node where we are actually still sleeping.
            # Change test_result.watcher_period outside this loop if you wish
            # to change sleep duration.
            next_deadline = now + test_result.watcher_period
            for section, (test_line, tester, target_computer) in list(running_test_dict.items()):
                logger.info('Checking %s: %r...', section, tester)

                computer_state = slap.registerComputer(target_computer).getStatus()

                # check if the computer has successfullly connected to report its status.

                if not computer_state['text'].startswith('#access'):
                    error_msg = 'Error while retrieving computer status for %s (%s). Test and teardown skipped.' % (
                                                section, computer_state['text'])
                    logger.error(error_msg)
                    test_line.stop(
                        test_count=1,
                        error_count=0,
                        failure_count=1,
                        skip_count=0,
                        stderr=error_msg,
                    )
                    del running_test_dict[section]
                    continue

                # check if the computer has connected in the last 15 minutes
                # if it has not: report the failure, skip the rest of the test and the teardown as well.

                server_response_age = compute_response_age(computer_state['created_at'])

                if server_response_age > 60*15:
                    error_msg = 'Computer is unavailable (since %s minutes) for %s. Test and teardown skipped.' % (
                                                int(server_response_age/60), section)
                    logger.error(error_msg)
                    test_line.stop(
                        test_count=1,
                        error_count=0,
                        failure_count=1,
                        skip_count=0,
                        stderr=error_msg,
                    )
                    del running_test_dict[section]
                    continue

                try:
                    deadline = tester.tic(now)
                except Exception:
                    logger.exception('Test execution failed for %s' % section)
                    test_line.stop(
                        test_count=1,
                        error_count=1,
                        failure_count=0,
                        skip_count=0,
                        stderr=traceback.format_exc(),
                    )
                    del running_test_dict[section]
                    try:
                        tester.teardown()
                    except slapos.slap.NotFoundError:
                        # This exception is ignored because we cannot
                        # Teardown if SR URL do not exist.
                        logger.exception('Fail and not found')
                        pass
                    except Exception:
                        logger.exception('teardown failed, human '
                            'assistance needed for cleanup')
                        raise
                else:
                    logger.info('%r', tester)
                    if deadline is None:
                        # TODO: report how long each step took.
                        logger.info('Test execution finished for  %s' % (section))
                        test_line.stop(
                            test_count=1,
                            error_count=0,
                            failure_count=0,
                            skip_count=0,
                        )
                        del running_test_dict[section]
                        try:
                            tester.teardown()
                        except slapos.slap.NotFoundError:
                            # This exception is ignored because we cannot
                            # Teardown if SR URL do not exist.
                            logger.exception('Fail and not found')
                            pass
                        except Exception:
                            logger.exception('teardown failed, human '
                                 'assistance needed for cleanup')
                            raise

                    else:
                        next_deadline = min(deadline, next_deadline)
            if running_test_dict:
                to_sleep = next_deadline - time.time()
                if to_sleep > 0:
                    logger.info('Sleeping %is...', to_sleep)
                    time.sleep(to_sleep)
                if not test_result.isAlive():
                    for _, tester, computer_id in running_test_dict.itervalues():
                        tester.teardown()
    finally:
        if pidfile:
            setFinished(pidfile)
        # Help interpreter get rid of AutoSTemp instances.
        key_file_dict.clear()

if __name__ == '__main__':
    main()