import logging
import time
import re

from datetime import datetime
from notifications import build_repository_event_data
from util.jinjautil import get_template_env
from util.secscan import PRIORITY_LEVELS, get_priority_for_index

logger = logging.getLogger(__name__)

TEMPLATE_ENV = get_template_env("events")

class InvalidNotificationEventException(Exception):
  pass

class NotificationEvent(object):
  def __init__(self):
    pass

  def get_level(self, event_data, notification_data):
    """
    Returns a 'level' representing the severity of the event.
    Valid values are: 'info', 'warning', 'error', 'primary', 'success'
    """
    raise NotImplementedError

  def get_summary(self, event_data, notification_data):
    """
    Returns a human readable one-line summary for the given notification data.
    """
    raise NotImplementedError

  def get_message(self, event_data, notification_data):
    """
    Returns a human readable HTML message for the given notification data.
    """
    return TEMPLATE_ENV.get_template(self.event_name() + '.html').render({
      'event_data': event_data,
      'notification_data': notification_data
    })

  def get_sample_data(self, namespace_name, repo_name, event_config):
    """
    Returns sample data for testing the raising of this notification, with an example notification.
    """
    raise NotImplementedError

  def should_perform(self, event_data, notification_data):
    """
    Whether a notification for this event should be performed. By default returns True.
    """
    return True

  @classmethod
  def event_name(cls):
    """
    Particular event implemented by subclasses.
    """
    raise NotImplementedError

  @classmethod
  def get_event(cls, eventname):
    found = NotificationEvent._get_event(cls, eventname)
    if found is not None:
      return found

    raise InvalidNotificationEventException('Unable to find event: %s' % eventname)

  @classmethod
  def event_names(cls):
    for subc in cls.__subclasses__():
      if subc.event_name() is None:
        for subsubc in subc.__subclasses__():
          yield subsubc.event_name()
      else:
        yield subc.event_name()

  @staticmethod
  def _get_event(cls, eventname):
    for subc in cls.__subclasses__():
      if subc.event_name() is None:
        found = NotificationEvent._get_event(subc, eventname)
        if found is not None:
          return found
      elif subc.event_name() == eventname:
        return subc()


class RepoPushEvent(NotificationEvent):
  @classmethod
  def event_name(cls):
    return 'repo_push'

  def get_level(self, event_data, notification_data):
    return 'primary'

  def get_summary(self, event_data, notification_data):
    return 'Repository %s updated' % (event_data['repository'])

  def get_sample_data(self, namespace_name, repo_name, event_config):
    return build_repository_event_data(namespace_name, repo_name, {
      'updated_tags': ['latest', 'foo'],
      'pruned_image_count': 3
    })


def _build_summary(event_data):
  """ Returns a summary string for the build data found in the event data block. """
  summary = 'for repository %s [%s]' % (event_data['repository'], event_data['build_id'][0:7])
  return summary


class VulnerabilityFoundEvent(NotificationEvent):
  CONFIG_LEVEL = 'level'
  PRIORITY_KEY = 'priority'
  VULNERABILITY_KEY = 'vulnerability'
  MULTIPLE_VULNERABILITY_KEY = 'vulnerabilities'

  @classmethod
  def event_name(cls):
    return 'vulnerability_found'

  def get_level(self, event_data, notification_data):
    vuln_data = event_data[VulnerabilityFoundEvent.VULNERABILITY_KEY]
    priority = vuln_data[VulnerabilityFoundEvent.PRIORITY_KEY]
    if priority == 'Defcon1' or priority == 'Critical':
      return 'error'

    if priority == 'Medium' or priority == 'High':
      return 'warning'

    return 'info'

  def get_sample_data(self, namespace_name, repo_name, event_config):
    level = event_config.get(VulnerabilityFoundEvent.CONFIG_LEVEL, 'Critical')
    return build_repository_event_data(namespace_name, repo_name,  {
      'tags': ['latest', 'prod', 'foo', 'bar', 'baz'],
      'image': 'some-image-id',
      'vulnerability': {
        'id': 'CVE-FAKE-CVE',
        'description': 'A futurist vulnerability',
        'link': 'https://security-tracker.debian.org/tracker/CVE-FAKE-CVE',
        'priority': get_priority_for_index(level)
      },
    })

  def should_perform(self, event_data, notification_data):
    event_config = notification_data.event_config_dict
    if VulnerabilityFoundEvent.CONFIG_LEVEL not in event_config:
      return True

    if VulnerabilityFoundEvent.VULNERABILITY_KEY not in event_data:
      return False

    vuln_info = event_data.get(VulnerabilityFoundEvent.VULNERABILITY_KEY, {})
    event_severity = PRIORITY_LEVELS.get(vuln_info.get('priority', 'Unknown'))
    if event_severity is None:
      return False

    actual_level_index = int(event_severity['index'])
    filter_level_index = int(event_config[VulnerabilityFoundEvent.CONFIG_LEVEL])
    return actual_level_index <= filter_level_index

  def get_summary(self, event_data, notification_data):
    vuln_key = VulnerabilityFoundEvent.VULNERABILITY_KEY
    priority_key = VulnerabilityFoundEvent.PRIORITY_KEY

    multiple_vulns = event_data.get(VulnerabilityFoundEvent.MULTIPLE_VULNERABILITY_KEY)
    if multiple_vulns is not None:
      top_priority = multiple_vulns[0].get(priority_key, 'Unknown')
      matching = [v for v in multiple_vulns if v.get(priority_key, 'Unknown') == top_priority]

      msg = '%s %s' % (len(matching), top_priority)
      if len(matching) < len(multiple_vulns):
        msg += ' and %s more' % (len(multiple_vulns) - len(matching))

      msg += ' vulnerabilities were detected in repository %s in %s tags'
      return msg % (event_data['repository'], len(event_data['tags']))
    else:
      msg = '%s vulnerability detected in repository %s in %s tags'
      return msg % (event_data[vuln_key][priority_key], event_data['repository'],
                    len(event_data['tags']))


class BaseBuildEvent(NotificationEvent):
  @classmethod
  def event_name(cls):
    return None

  def should_perform(self, event_data, notification_data):
    if not notification_data.event_config_dict:
      return True

    event_config = notification_data.event_config_dict
    ref_regex = event_config.get('ref-regex') or None
    if ref_regex is None:
      return True

    # Lookup the ref. If none, this is a non-git build and we should not fire the event.
    ref = event_data.get('trigger_metadata', {}).get('ref', None)
    if ref is None:
      return False

    # Try parsing the regex string as a regular expression. If we fail, we fail to fire
    # the event.
    try:
      return bool(re.compile(str(ref_regex)).match(ref))
    except Exception:
      logger.warning('Regular expression error for build event filter: %s', ref_regex)
      return False


class BuildQueueEvent(BaseBuildEvent):
  @classmethod
  def event_name(cls):
    return 'build_queued'

  def get_level(self, event_data, notification_data):
    return 'info'

  def get_sample_data(self, namespace_name, repo_name, event_config):
    build_uuid = 'fake-build-id'
    return build_repository_event_data(namespace_name, repo_name,  {
      'is_manual': False,
      'build_id': build_uuid,
      'build_name': 'some-fake-build',
      'docker_tags': ['latest', 'foo', 'bar'],
      'trigger_id': '1245634',
      'trigger_kind': 'GitHub',
      'trigger_metadata': {
        "default_branch": "master",
        "ref": "refs/heads/somebranch",
        "commit": "42d4a62c53350993ea41069e9f2cfdefb0df097d",
        "commit_info": {
          'url': 'http://path/to/the/commit',
          'message': 'Some commit message',
          'date': time.mktime(datetime.now().timetuple()),
          'author': {
            'username': 'fakeauthor',
            'url': 'http://path/to/fake/author/in/scm',
            'avatar_url': 'http://www.gravatar.com/avatar/fakehash'
          }
        }
      }
    }, subpage='/build/%s' % build_uuid)

  def get_summary(self, event_data, notification_data):
    return 'Build queued ' + _build_summary(event_data)


class BuildStartEvent(BaseBuildEvent):
  @classmethod
  def event_name(cls):
    return 'build_start'

  def get_level(self, event_data, notification_data):
    return 'info'

  def get_sample_data(self, namespace_name, repo_name, event_config):
    build_uuid = 'fake-build-id'
    return build_repository_event_data(namespace_name, repo_name,  {
      'build_id': build_uuid,
      'build_name': 'some-fake-build',
      'docker_tags': ['latest', 'foo', 'bar'],
      'trigger_id': '1245634',
      'trigger_kind': 'GitHub',
      'trigger_metadata': {
        "default_branch": "master",
        "ref": "refs/heads/somebranch",
        "commit": "42d4a62c53350993ea41069e9f2cfdefb0df097d"
      }
    }, subpage='/build/%s' % build_uuid)

  def get_summary(self, event_data, notification_data):
    return 'Build started ' + _build_summary(event_data)


class BuildSuccessEvent(BaseBuildEvent):
  @classmethod
  def event_name(cls):
    return 'build_success'

  def get_level(self, event_data, notification_data):
    return 'success'

  def get_sample_data(self, namespace_name, repo_name, event_config):
    build_uuid = 'fake-build-id'
    return build_repository_event_data(namespace_name, repo_name,  {
      'build_id': build_uuid,
      'build_name': 'some-fake-build',
      'docker_tags': ['latest', 'foo', 'bar'],
      'trigger_id': '1245634',
      'trigger_kind': 'GitHub',
      'trigger_metadata': {
        "default_branch": "master",
        "ref": "refs/heads/somebranch",
        "commit": "42d4a62c53350993ea41069e9f2cfdefb0df097d"
      },
      'image_id': '1245657346'
    }, subpage='/build/%s' % build_uuid)

  def get_summary(self, event_data, notification_data):
    return 'Build succeeded ' + _build_summary(event_data)


class BuildFailureEvent(BaseBuildEvent):
  @classmethod
  def event_name(cls):
    return 'build_failure'

  def get_level(self, event_data, notification_data):
    return 'error'

  def get_sample_data(self, namespace_name, repo_name, event_config):
    build_uuid = 'fake-build-id'
    return build_repository_event_data(namespace_name, repo_name,  {
      'build_id': build_uuid,
      'build_name': 'some-fake-build',
      'docker_tags': ['latest', 'foo', 'bar'],
      'trigger_kind': 'GitHub',
      'error_message': 'This is a fake error message',
      'trigger_id': '1245634',
      'trigger_kind': 'GitHub',
      'trigger_metadata': {
        "default_branch": "master",
        "ref": "refs/heads/somebranch",
        "commit": "42d4a62c53350993ea41069e9f2cfdefb0df097d",
        "commit_info": {
          'url': 'http://path/to/the/commit',
          'message': 'Some commit message',
          'date': time.mktime(datetime.now().timetuple()),
          'author': {
            'username': 'fakeauthor',
            'url': 'http://path/to/fake/author/in/scm',
            'avatar_url': 'http://www.gravatar.com/avatar/fakehash'
          }
        }
      }
    }, subpage='/build/%s' % build_uuid)

  def get_summary(self, event_data, notification_data):
    return 'Build failure ' + _build_summary(event_data)


class BuildCancelledEvent(BaseBuildEvent):
  @classmethod
  def event_name(cls):
    return 'build_cancelled'

  def get_level(self, event_data, notification_data):
    return 'info'

  def get_sample_data(self, namespace_name, repo_name, event_config):
    build_uuid = 'fake-build-id'
    return build_repository_event_data(namespace_name, repo_name,  {
      'build_id': build_uuid,
      'build_name': 'some-fake-build',
      'docker_tags': ['latest', 'foo', 'bar'],
      'trigger_id': '1245634',
      'trigger_kind': 'GitHub',
      'trigger_metadata': {
        "default_branch": "master",
        "ref": "refs/heads/somebranch",
        "commit": "42d4a62c53350993ea41069e9f2cfdefb0df097d"
      },
      'image_id': '1245657346'
    }, subpage='/build/%s' % build_uuid)

  def get_summary(self, event_data, notification_data):
    return 'Build cancelled ' + _build_summary(event_data)