import logging
import os
import json
import signal

from flask import abort, Response
from endpoints.api import (ApiResource, nickname, resource, internal_only, show_if,
                           require_fresh_login, request, validate_json_request, verify_not_prod)

from endpoints.common import common_login
from app import app, CONFIG_PROVIDER, superusers
from data import model
from data.database import configure
from auth.permissions import SuperUserPermission
from auth.auth_context import get_authenticated_user
from data.database import User
from util.config.configutil import add_enterprise_config_defaults
from util.config.validator import validate_service_for_config, SSL_FILENAMES
from data.runmigration import run_alembic_migration

import features

logger = logging.getLogger(__name__)

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

  try:
    list(User.select().limit(1))
    return True
  except:
    return False


def database_has_users():
  """ Returns whether the database has any users defined. """
  return bool(list(User.select().limit(1)))


@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 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.yaml_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'
      }

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

    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.yaml_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_yaml())

      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)



@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(1, 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': {
      'id': 'UpdateConfig',
      'type': 'object',
      'description': 'Updates the YAML config file',
      'required': [
        'config',
        'hostname'
      ],
      'properties': {
        'config': {
          'type': 'object'
        },
        'hostname': {
          '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_yaml()
      return {
        'config': config_object
      }

    abort(403)

  @nickname('scUpdateConfig')
  @verify_not_prod
  @validate_json_request('UpdateConfig')
  def put(self):
    """ Updates the config.yaml 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.yaml_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 YAML file.
      CONFIG_PROVIDER.save_yaml(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 filename in SSL_FILENAMES:
      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 filename in SSL_FILENAMES:
      abort(404)

    if SuperUserPermission().can():
      uploaded_file = request.files['file']
      if not uploaded_file:
        abort(400)

      CONFIG_PROVIDER.save_volume_file(filename, uploaded_file)
      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': {
      'id': '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.yaml_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 = model.create_user(username, password, email, auto_verify=True)

      # Add the user to the config.
      config_object = CONFIG_PROVIDER.get_yaml()
      config_object['SUPER_USERS'] = [username]
      CONFIG_PROVIDER.save_yaml(config_object)

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

      # Conduct login with that user.
      common_login(superuser)

      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': {
      'id': 'ValidateConfig',
      'type': 'object',
      'description': 'Validates configuration',
      'required': [
        'config'
      ],
      'properties': {
        'config': {
          'type': 'object'
        }
      },
    },
  }

  @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.yaml_exists() or SuperUserPermission().can():
      config = request.get_json()['config']
      return validate_service_for_config(service, config)

    abort(403)