""" Superuser Config API. """

import logging
import os
import signal
import subprocess

from flask import abort

from app import app, config_provider, superusers, OVERRIDE_CONFIG_DIRECTORY, ip_resolver
from auth.permissions import SuperUserPermission
from auth.auth_context import get_authenticated_user
from data.database import configure
from data.runmigration import run_alembic_migration
from data.users import get_federated_service_name, get_users_handler
from endpoints.api.suconfig_models_pre_oci import pre_oci_model as model
from endpoints.api import (ApiResource, nickname, resource, internal_only, show_if,
                           require_fresh_login, request, validate_json_request, verify_not_prod,
                           InvalidRequest)
from endpoints.common import common_login
from util.config.configutil import add_enterprise_config_defaults
from util.config.database import sync_database_with_config
from util.config.validator import validate_service_for_config, is_valid_config_upload_filename, ValidatorContext

import features


logger = logging.getLogger(__name__)


def database_is_valid():
  """ Returns whether the database, as configured, is valid. """
  if app.config['TESTING']:
    return False

  return model.is_valid()


def database_has_users():
  """ Returns whether the database has any users defined. """
  return model.has_users()


@resource('/v1/superuser/registrystatus')
@internal_only
@show_if(features.SUPER_USERS)
class SuperUserRegistryStatus(ApiResource):
  """ Resource for determining the status of the registry, such as if config exists,
      if a database is configured, and if it has any defined users.
  """
  @nickname('scRegistryStatus')
  @verify_not_prod
  def get(self):
    """ Returns the status of the registry. """

    # If we have SETUP_COMPLETE, then we're ready to go!
    if app.config.get('SETUP_COMPLETE', False):
      return {
        'provider_id': config_provider.provider_id,
        'requires_restart': config_provider.requires_restart(app.config),
        'status': 'ready'
      }

    # If there is no conf/stack volume, then report that status.
    if not config_provider.volume_exists():
      return {
        'status': 'missing-config-dir'
      }

    # If there is no config file, we need to setup the database.
    if not config_provider.config_exists():
      return {
        'status': 'config-db'
      }

    # If the database isn't yet valid, then we need to set it up.
    if not database_is_valid():
      return {
        'status': 'setup-db'
      }

    return {
      'status': 'create-superuser' if not database_has_users() else 'config'
    }


class _AlembicLogHandler(logging.Handler):
  def __init__(self):
    super(_AlembicLogHandler, self).__init__()
    self.records = []

  def emit(self, record):
    self.records.append({
      'level': record.levelname,
      'message': record.getMessage()
    })

@resource('/v1/superuser/setupdb')
@internal_only
@show_if(features.SUPER_USERS)
class SuperUserSetupDatabase(ApiResource):
  """ Resource for invoking alembic to setup the database. """
  @verify_not_prod
  @nickname('scSetupDatabase')
  def get(self):
    """ Invokes the alembic upgrade process. """
    # Note: This method is called after the database configured is saved, but before the
    # database has any tables. Therefore, we only allow it to be run in that unique case.
    if config_provider.config_exists() and not database_is_valid():
      # Note: We need to reconfigure the database here as the config has changed.
      combined = dict(**app.config)
      combined.update(config_provider.get_config())

      configure(combined)
      app.config['DB_URI'] = combined['DB_URI']

      log_handler = _AlembicLogHandler()

      try:
        run_alembic_migration(log_handler)
      except Exception as ex:
        return {
          'error': str(ex)
        }

      return {
        'logs': log_handler.records
      }

    abort(403)


# From: https://stackoverflow.com/a/44712205
def get_process_id(name):
    """Return process ids found by (partial) name or regex.

    >>> get_process_id('kthreadd')
    [2]
    >>> get_process_id('watchdog')
    [10, 11, 16, 21, 26, 31, 36, 41, 46, 51, 56, 61]  # ymmv
    >>> get_process_id('non-existent process')
    []
    """
    child = subprocess.Popen(['pgrep', name], stdout=subprocess.PIPE, shell=False)
    response = child.communicate()[0]
    return [int(pid) for pid in response.split()]


@resource('/v1/superuser/shutdown')
@internal_only
@show_if(features.SUPER_USERS)
class SuperUserShutdown(ApiResource):
  """ Resource for sending a shutdown signal to the container. """

  @verify_not_prod
  @nickname('scShutdownContainer')
  def post(self):
    """ Sends a signal to the phusion init system to shut down the container. """
    # Note: This method is called to set the database configuration before super users exists,
    # so we also allow it to be called if there is no valid registry configuration setup.
    if app.config['TESTING'] or not database_has_users() or SuperUserPermission().can():
      # Note: We skip if debugging locally.
      if app.config.get('DEBUGGING') == True:
        return {}

      os.kill(get_process_id('my_init')[0], signal.SIGINT)
      return {}

    abort(403)


@resource('/v1/superuser/config')
@internal_only
@show_if(features.SUPER_USERS)
class SuperUserConfig(ApiResource):
  """ Resource for fetching and updating the current configuration, if any. """
  schemas = {
    'UpdateConfig': {
      'type': 'object',
      'description': 'Updates the YAML config file',
      'required': [
        'config',
        'hostname'
      ],
      'properties': {
        'config': {
          'type': 'object'
        },
        'hostname': {
          'type': 'string'
        },
        'password': {
          'type': 'string'
        },
      },
    },
  }

  @require_fresh_login
  @verify_not_prod
  @nickname('scGetConfig')
  def get(self):
    """ Returns the currently defined configuration, if any. """
    if SuperUserPermission().can():
      config_object = config_provider.get_config()
      return {
        'config': config_object
      }

    abort(403)

  @nickname('scUpdateConfig')
  @verify_not_prod
  @validate_json_request('UpdateConfig')
  def put(self):
    """ Updates the config override file. """
    # Note: This method is called to set the database configuration before super users exists,
    # so we also allow it to be called if there is no valid registry configuration setup.
    if not config_provider.config_exists() or SuperUserPermission().can():
      config_object = request.get_json()['config']
      hostname = request.get_json()['hostname']

      # Add any enterprise defaults missing from the config.
      add_enterprise_config_defaults(config_object, app.config['SECRET_KEY'], hostname)

      # Write the configuration changes to the config override file.
      config_provider.save_config(config_object)

      # If the authentication system is federated, link the superuser account to the
      # the authentication system chosen.
      service_name = get_federated_service_name(config_object['AUTHENTICATION_TYPE'])
      if service_name is not None:
        current_user = get_authenticated_user()
        if current_user is None:
          abort(401)

        service_name = get_federated_service_name(config_object['AUTHENTICATION_TYPE'])
        if not model.has_federated_login(current_user.username, service_name):
          # Verify the user's credentials and retrieve the user's external username+email.
          handler = get_users_handler(config_object, config_provider, OVERRIDE_CONFIG_DIRECTORY)
          (result, err_msg) = handler.verify_credentials(current_user.username,
                                                         request.get_json().get('password', ''))
          if not result:
            logger.error('Could not save configuration due to external auth failure: %s', err_msg)
            abort(400)

          # Link the existing user to the external user.
          model.attach_federated_login(current_user.username, service_name, result.username)

      # Ensure database is up-to-date with config
      sync_database_with_config(config_object)

      return {
        'exists': True,
        'config': config_object
      }

    abort(403)


@resource('/v1/superuser/config/file/<filename>')
@internal_only
@show_if(features.SUPER_USERS)
class SuperUserConfigFile(ApiResource):
  """ Resource for fetching the status of config files and overriding them. """
  @nickname('scConfigFileExists')
  @verify_not_prod
  def get(self, filename):
    """ Returns whether the configuration file with the given name exists. """
    if not is_valid_config_upload_filename(filename):
      abort(404)

    if SuperUserPermission().can():
      return {
        'exists': config_provider.volume_file_exists(filename)
      }

    abort(403)

  @nickname('scUpdateConfigFile')
  @verify_not_prod
  def post(self, filename):
    """ Updates the configuration file with the given name. """
    if not is_valid_config_upload_filename(filename):
      abort(404)

    # Note: This method can be called before the configuration exists
    # to upload the database SSL cert.
    if not config_provider.config_exists() or SuperUserPermission().can():
      uploaded_file = request.files['file']
      if not uploaded_file:
        abort(400)

      config_provider.save_volume_file(uploaded_file, filename)
      return {
        'status': True
      }

    abort(403)


@resource('/v1/superuser/config/createsuperuser')
@internal_only
@show_if(features.SUPER_USERS)
class SuperUserCreateInitialSuperUser(ApiResource):
  """ Resource for creating the initial super user. """
  schemas = {
    'CreateSuperUser': {
      'type': 'object',
      'description': 'Information for creating the initial super user',
      'required': [
        'username',
        'password',
        'email'
      ],
      'properties': {
        'username': {
          'type': 'string',
          'description': 'The username for the superuser'
        },
        'password': {
          'type': 'string',
          'description': 'The password for the superuser'
        },
        'email': {
          'type': 'string',
          'description': 'The e-mail address for the superuser'
        },
      },
    },
  }

  @nickname('scCreateInitialSuperuser')
  @verify_not_prod
  @validate_json_request('CreateSuperUser')
  def post(self):
    """ Creates the initial super user, updates the underlying configuration and
        sets the current session to have that super user. """

    # Special security check: This method is only accessible when:
    #   - There is a valid config YAML file.
    #   - There are currently no users in the database (clean install)
    #
    # We do this special security check because at the point this method is called, the database
    # is clean but does not (yet) have any super users for our permissions code to check against.
    if config_provider.config_exists() and not database_has_users():
      data = request.get_json()
      username = data['username']
      password = data['password']
      email = data['email']

      # Create the user in the database.
      superuser_uuid = model.create_superuser(username, password, email)

      # Add the user to the config.
      config_object = config_provider.get_config()
      config_object['SUPER_USERS'] = [username]
      config_provider.save_config(config_object)

      # Update the in-memory config for the new superuser.
      superusers.register_superuser(username)

      # Conduct login with that user.
      common_login(superuser_uuid)

      return {
        'status': True
      }


    abort(403)


@resource('/v1/superuser/config/validate/<service>')
@internal_only
@show_if(features.SUPER_USERS)
class SuperUserConfigValidate(ApiResource):
  """ Resource for validating a block of configuration against an external service. """
  schemas = {
    'ValidateConfig': {
      'type': 'object',
      'description': 'Validates configuration',
      'required': [
        'config'
      ],
      'properties': {
        'config': {
          'type': 'object'
        },
        'password': {
          'type': 'string',
          'description': 'The users password, used for auth validation'
        }
      },
    },
  }

  @nickname('scValidateConfig')
  @verify_not_prod
  @validate_json_request('ValidateConfig')
  def post(self, service):
    """ Validates the given config for the given service. """
    # Note: This method is called to validate the database configuration before super users exists,
    # so we also allow it to be called if there is no valid registry configuration setup. Note that
    # this is also safe since this method does not access any information not given in the request.
    if not config_provider.config_exists() or SuperUserPermission().can():
      config = request.get_json()['config']
      validator_context = ValidatorContext.from_app(config, request.get_json().get('password', ''), app,
                                                    ip_resolver=ip_resolver,
                                                    config_provider=config_provider)

      return validate_service_for_config(service, validator_context)

    abort(403)