import bcrypt
import logging
import json
import uuid
from flask.ext.login import UserMixin

from peewee import JOIN_LEFT_OUTER, IntegrityError, fn
from uuid import uuid4
from datetime import datetime, timedelta
from enum import Enum

from data.database import (User, LoginService, FederatedLogin, RepositoryPermission, TeamMember,
                           Team, Repository, TupleSelector, TeamRole, Namespace, Visibility,
                           EmailConfirmation, Role, db_for_update, random_string_generator,
                           UserRegion, ImageStorageLocation,
                           ServiceKeyApproval, OAuthApplication, RepositoryBuildTrigger,
                           UserPromptKind, UserPrompt, UserPromptTypes)
from data.model import (DataModelException, InvalidPasswordException, InvalidRobotException,
                        InvalidUsernameException, InvalidEmailAddressException,
                        TooManyLoginAttemptsException, db_transaction,
                        notification, config, repository, _basequery)
from data.text import prefix_search
from util.names import format_robot_username, parse_robot_username
from util.validation import (validate_username, validate_email, validate_password,
                             INVALID_PASSWORD_MESSAGE)
from util.backoff import exponential_backoff


logger = logging.getLogger(__name__)


EXPONENTIAL_BACKOFF_SCALE = timedelta(seconds=1)

def hash_password(password, salt=None):
  salt = salt or bcrypt.gensalt()
  return bcrypt.hashpw(password.encode('utf-8'), salt)

def create_user(username, password, email, auto_verify=False, email_required=True, prompts=tuple()):
  """ Creates a regular user, if allowed. """
  if not validate_password(password):
    raise InvalidPasswordException(INVALID_PASSWORD_MESSAGE)

  created = create_user_noverify(username, email, email_required=email_required, prompts=prompts)
  created.password_hash = hash_password(password)
  created.verified = auto_verify
  created.save()

  return created


def create_user_noverify(username, email, email_required=True, prompts=tuple()):
  if email_required:
    if not validate_email(email):
      raise InvalidEmailAddressException('Invalid email address: %s' % email)
  else:
    # If email addresses are not required and none was specified, then we just use a unique
    # ID to ensure that the database consistency check remains intact.
    email = email or str(uuid.uuid4())

  (username_valid, username_issue) = validate_username(username)
  if not username_valid:
    raise InvalidUsernameException('Invalid namespace %s: %s' % (username, username_issue))

  try:
    existing = User.get((User.username == username) | (User.email == email))

    logger.info('Existing user with same username or email.')

    # A user already exists with either the same username or email
    if existing.username == username:
      raise InvalidUsernameException('Username has already been taken: %s' %
                                     username)
    raise InvalidEmailAddressException('Email has already been used: %s' %
                                       email)

  except User.DoesNotExist:
    # This is actually the happy path
    logger.debug('Email and username are unique!')

  try:
    new_user = User.create(username=username, email=email)
    for prompt in prompts:
      create_user_prompt(new_user, prompt)

    return new_user
  except Exception as ex:
    raise DataModelException(ex.message)


def is_username_unique(test_username):
  try:
    User.get((User.username == test_username))
    return False
  except User.DoesNotExist:
    return True


def change_password(user, new_password):
  if not validate_password(new_password):
    raise InvalidPasswordException(INVALID_PASSWORD_MESSAGE)

  pw_hash = hash_password(new_password)
  user.invalid_login_attempts = 0
  user.password_hash = pw_hash
  user.uuid = str(uuid4())
  user.save()

  # Remove any password required notifications for the user.
  notification.delete_notifications_by_kind(user, 'password_required')


def get_default_user_prompts(features):
  prompts = set()
  if features.USER_METADATA:
    prompts.add(UserPromptTypes.ENTER_NAME)
    prompts.add(UserPromptTypes.ENTER_COMPANY)

  return prompts


def has_user_prompts(user):
  try:
    UserPrompt.select().where(UserPrompt.user == user).get()
    return True
  except UserPrompt.DoesNotExist:
    return False


def has_user_prompt(user, prompt_name):
  prompt_kind = UserPromptKind.get(name=prompt_name)

  try:
    UserPrompt.get(user=user, kind=prompt_kind)
    return True
  except UserPrompt.DoesNotExist:
    return False


def create_user_prompt(user, prompt_name):
  prompt_kind = UserPromptKind.get(name=prompt_name)
  return UserPrompt.create(user=user, kind=prompt_kind)


def remove_user_prompt(user, prompt_name):
  prompt_kind = UserPromptKind.get(name=prompt_name)
  UserPrompt.delete().where(UserPrompt.user == user, UserPrompt.kind == prompt_kind).execute()


def get_user_prompts(user):
  query = UserPrompt.select().where(UserPrompt.user == user).join(UserPromptKind)
  return [prompt.kind.name for prompt in query]


def change_username(user_id, new_username):
  (username_valid, username_issue) = validate_username(new_username)
  if not username_valid:
    raise InvalidUsernameException('Invalid username %s: %s' % (new_username, username_issue))

  with db_transaction():
    # Reload the user for update
    user = db_for_update(User.select().where(User.id == user_id)).get()

    # Rename the robots
    for robot in db_for_update(_list_entity_robots(user.username)):
      _, robot_shortname = parse_robot_username(robot.username)
      new_robot_name = format_robot_username(new_username, robot_shortname)
      robot.username = new_robot_name
      robot.save()

    # Rename the user
    user.username = new_username
    user.save()

    # Remove any prompts for username.
    remove_user_prompt(user, 'confirm_username')

    return user


def change_invoice_email_address(user, invoice_email_address):
  # Note: We null out the address if it is an empty string.
  user.invoice_email_address = invoice_email_address or None
  user.save()


def change_send_invoice_email(user, invoice_email):
  user.invoice_email = invoice_email
  user.save()


def change_user_tag_expiration(user, tag_expiration_s):
  user.removed_tag_expiration_s = tag_expiration_s
  user.save()


def update_email(user, new_email, auto_verify=False):
  try:
    user.email = new_email
    user.verified = auto_verify
    user.save()
  except IntegrityError:
    raise DataModelException('E-mail address already used')


def create_robot(robot_shortname, parent):
  (username_valid, username_issue) = validate_username(robot_shortname)
  if not username_valid:
    raise InvalidRobotException('The name for the robot \'%s\' is invalid: %s' %
                                (robot_shortname, username_issue))

  username = format_robot_username(parent.username, robot_shortname)

  try:
    User.get(User.username == username)

    msg = 'Existing robot with name: %s' % username
    logger.info(msg)
    raise InvalidRobotException(msg)

  except User.DoesNotExist:
    pass

  try:
    created = User.create(username=username, robot=True)

    service = LoginService.get(name='quayrobot')
    password = created.email
    FederatedLogin.create(user=created, service=service,
                          service_ident=password)

    return created, password
  except Exception as ex:
    raise DataModelException(ex.message)


def get_robot(robot_shortname, parent):
  robot_username = format_robot_username(parent.username, robot_shortname)
  robot = lookup_robot(robot_username)
  return robot, robot.email


def lookup_robot(robot_username):
  try:
    return (User
            .select()
            .join(FederatedLogin)
            .join(LoginService)
            .where(LoginService.name == 'quayrobot', User.username == robot_username,
                   User.robot == True)
            .get())
  except User.DoesNotExist:
    raise InvalidRobotException('Could not find robot with username: %s' % robot_username)


def get_matching_robots(name_prefix, username, limit=10):
  admined_orgs = (_basequery.get_user_organizations(username)
                  .switch(Team)
                  .join(TeamRole)
                  .where(TeamRole.name == 'admin'))

  prefix_checks = False

  for org in admined_orgs:
    org_search =  prefix_search(User.username, org.username + '+' + name_prefix)
    prefix_checks = prefix_checks | org_search

  user_search =  prefix_search(User.username, username + '+' + name_prefix)
  prefix_checks = prefix_checks | user_search

  return User.select().where(prefix_checks).limit(limit)


def verify_robot(robot_username, password):
  result = parse_robot_username(robot_username)
  if result is None:
    raise InvalidRobotException('%s is an invalid robot name' % robot_username)

  # Find the matching robot.
  query = (User
           .select()
           .join(FederatedLogin)
           .join(LoginService)
           .where(FederatedLogin.service_ident == password, LoginService.name == 'quayrobot',
                  User.username == robot_username))

  try:
    robot = query.get()
  except User.DoesNotExist:
    msg = ('Could not find robot with username: %s and supplied password.' %
           robot_username)
    raise InvalidRobotException(msg)

  # Find the owner user and ensure it is not disabled.
  try:
    owner = User.get(User.username == result[0])
  except User.DoesNotExist:
    raise InvalidRobotException('Robot %s owner does not exist' % robot_username)

  if not owner.enabled:
    raise InvalidRobotException('This user has been disabled. Please contact your administrator.')

  return robot

def regenerate_robot_token(robot_shortname, parent):
  robot_username = format_robot_username(parent.username, robot_shortname)

  robot = lookup_robot(robot_username)
  password = random_string_generator(length=64)()
  robot.email = password
  robot.uuid = str(uuid4())

  service = LoginService.get(name='quayrobot')
  login = FederatedLogin.get(FederatedLogin.user == robot, FederatedLogin.service == service)
  login.service_ident = password

  login.save()
  robot.save()

  return robot, password

def delete_robot(robot_username):
  try:
    robot = User.get(username=robot_username, robot=True)
    robot.delete_instance(recursive=True, delete_nullable=True)

  except User.DoesNotExist:
    raise InvalidRobotException('Could not find robot with username: %s' %
                                robot_username)


def list_namespace_robots(namespace):
  """ Returns all the robots found under the given namespace. """
  return _list_entity_robots(namespace)


def _list_entity_robots(entity_name):
  """ Return the list of robots for the specified entity. This MUST return a query, not a
      materialized list so that callers can use db_for_update.
      """
  return (User
          .select()
          .join(FederatedLogin)
          .where(User.robot == True, User.username ** (entity_name + '+%')))


def list_entity_robot_permission_teams(entity_name, include_permissions=False):
  query = (_list_entity_robots(entity_name))

  fields = [User.username, FederatedLogin.service_ident]
  if include_permissions:
    query = (query
             .join(RepositoryPermission, JOIN_LEFT_OUTER,
                   on=(RepositoryPermission.user == FederatedLogin.user))
             .join(Repository, JOIN_LEFT_OUTER)
             .switch(User)
             .join(TeamMember, JOIN_LEFT_OUTER)
             .join(Team, JOIN_LEFT_OUTER))

    fields.append(Repository.name)
    fields.append(Team.name)

  return TupleSelector(query, fields)


def update_user_metadata(user, given_name=None, family_name=None, company=None):
  """ Updates the metadata associated with the user, including his/her name and company. """
  with db_transaction():
    user.given_name = given_name or user.given_name
    user.family_name = family_name or user.family_name
    user.company = company or user.company
    user.save()

    # Remove any prompts associated with the user's metadata being needed.
    remove_user_prompt(user, UserPromptTypes.ENTER_NAME)
    remove_user_prompt(user, UserPromptTypes.ENTER_COMPANY)


def _get_login_service(service_id):
  try:
    return LoginService.get(LoginService.name == service_id)
  except LoginService.DoesNotExist:
    return LoginService.create(name=service_id)


def create_federated_user(username, email, service_id, service_ident,
                          set_password_notification, metadata={},
                          email_required=True, prompts=tuple()):
  prompts = set(prompts)
  prompts.add(UserPromptTypes.CONFIRM_USERNAME)

  new_user = create_user_noverify(username, email, email_required=email_required, prompts=prompts)
  new_user.verified = True
  new_user.save()

  FederatedLogin.create(user=new_user, service=_get_login_service(service_id),
                        service_ident=service_ident,
                        metadata_json=json.dumps(metadata))

  if set_password_notification:
    notification.create_notification('password_required', new_user)

  return new_user


def attach_federated_login(user, service_id, service_ident, metadata=None):
  service = _get_login_service(service_id)
  FederatedLogin.create(user=user, service=service, service_ident=service_ident,
                        metadata_json=json.dumps(metadata or {}))
  return user


def verify_federated_login(service_id, service_ident):
  try:
    found = (FederatedLogin
             .select(FederatedLogin, User)
             .join(LoginService)
             .switch(FederatedLogin).join(User)
             .where(FederatedLogin.service_ident == service_ident, LoginService.name == service_id)
             .get())
    return found.user
  except FederatedLogin.DoesNotExist:
    return None


def list_federated_logins(user):
  selected = FederatedLogin.select(FederatedLogin.service_ident,
                                   LoginService.name, FederatedLogin.metadata_json)
  joined = selected.join(LoginService)
  return joined.where(LoginService.name != 'quayrobot',
                      FederatedLogin.user == user)


def lookup_federated_login(user, service_name):
  try:
    return list_federated_logins(user).where(LoginService.name == service_name).get()
  except FederatedLogin.DoesNotExist:
    return None


def create_confirm_email_code(user, new_email=None):
  if new_email:
    if not validate_email(new_email):
      raise InvalidEmailAddressException('Invalid email address: %s' %
                                         new_email)

  code = EmailConfirmation.create(user=user, email_confirm=True,
                                  new_email=new_email)
  return code


def confirm_user_email(code):
  try:
    code = EmailConfirmation.get(EmailConfirmation.code == code,
                                 EmailConfirmation.email_confirm == True)
  except EmailConfirmation.DoesNotExist:
    raise DataModelException('Invalid email confirmation code')

  user = code.user
  user.verified = True

  old_email = None
  new_email = code.new_email
  if new_email and new_email != old_email:
    if find_user_by_email(new_email):
      raise DataModelException('E-mail address already used')

    old_email = user.email
    user.email = new_email

  user.save()

  code.delete_instance()

  return user, new_email, old_email


def create_reset_password_email_code(email):
  try:
    user = User.get(User.email == email)
  except User.DoesNotExist:
    raise InvalidEmailAddressException('Email address was not found')

  if user.organization:
    raise InvalidEmailAddressException('Organizations can not have passwords')

  code = EmailConfirmation.create(user=user, pw_reset=True)
  return code


def validate_reset_code(code):
  try:
    code = EmailConfirmation.get(EmailConfirmation.code == code,
                                 EmailConfirmation.pw_reset == True)
  except EmailConfirmation.DoesNotExist:
    return None

  user = code.user
  if not user.verified:
    user.verified = True
    user.save()

  code.delete_instance()

  return user


def find_user_by_email(email):
  try:
    return User.get(User.email == email)
  except User.DoesNotExist:
    return None


def get_nonrobot_user(username):
  try:
    return User.get(User.username == username, User.organization == False, User.robot == False)
  except User.DoesNotExist:
    return None


def get_user(username):
  try:
    return User.get(User.username == username, User.organization == False)
  except User.DoesNotExist:
    return None


def get_namespace_user(username):
  try:
    return User.get(User.username == username)
  except User.DoesNotExist:
    return None


def get_user_or_org(username):
  try:
    return User.get(User.username == username, User.robot == False)
  except User.DoesNotExist:
    return None


def get_user_by_id(user_db_id):
  try:
    return User.get(User.id == user_db_id, User.organization == False)
  except User.DoesNotExist:
    return None


def get_namespace_user_by_user_id(namespace_user_db_id):
  try:
    return User.get(User.id == namespace_user_db_id, User.robot == False)
  except User.DoesNotExist:
    raise InvalidUsernameException('User with id does not exist: %s' % namespace_user_db_id)


def get_namespace_by_user_id(namespace_user_db_id):
  try:
    return User.get(User.id == namespace_user_db_id, User.robot == False).username
  except User.DoesNotExist:
    raise InvalidUsernameException('User with id does not exist: %s' % namespace_user_db_id)


def get_user_by_uuid(user_uuid):
  try:
    return User.get(User.uuid == user_uuid, User.organization == False)
  except User.DoesNotExist:
    return None


def get_user_or_org_by_customer_id(customer_id):
  try:
    return User.get(User.stripe_id == customer_id)
  except User.DoesNotExist:
    return None


def get_matching_user_namespaces(namespace_prefix, username, limit=10):
  namespace_search = prefix_search(Namespace.username, namespace_prefix)
  base_query = (Namespace
                .select()
                .distinct()
                .join(Repository, on=(Repository.namespace_user == Namespace.id))
                .join(RepositoryPermission, JOIN_LEFT_OUTER)
                .where(namespace_search))

  return _basequery.filter_to_repos_for_user(base_query, username).limit(limit)

def get_matching_users(username_prefix, robot_namespace=None, organization=None, limit=20):
  user_search =  prefix_search(User.username, username_prefix)
  direct_user_query = (user_search & (User.organization == False) & (User.robot == False))

  if robot_namespace:
    robot_prefix = format_robot_username(robot_namespace, username_prefix)
    robot_search = prefix_search(User.username, robot_prefix)
    direct_user_query = ((robot_search & (User.robot == True)) | direct_user_query)

  query = (User
           .select(User.id, User.username, User.email, User.robot)
           .group_by(User.id, User.username, User.email, User.robot)
           .where(direct_user_query))

  if organization:
    query = (query
             .select(User.id, User.username, User.email, User.robot, fn.Sum(Team.id))
             .join(TeamMember, JOIN_LEFT_OUTER)
             .join(Team, JOIN_LEFT_OUTER, on=((Team.id == TeamMember.team) &
                                              (Team.organization == organization)))
             .order_by(User.robot.desc()))

  class MatchingUserResult(object):
    def __init__(self, *args):
      self.id = args[0]
      self.username = args[1]
      self.email = args[2]
      self.robot = args[3]

      if organization:
        self.is_org_member = (args[3] != None)
      else:
        self.is_org_member = None

  return (MatchingUserResult(*args) for args in query.tuples().limit(limit))


def verify_user(username_or_email, password):
  # Make sure we didn't get any unicode for the username.
  try:
    str(username_or_email)
  except ValueError:
    return None

  try:
    fetched = User.get((User.username == username_or_email) |
                       (User.email == username_or_email))
  except User.DoesNotExist:
    return None

  now = datetime.utcnow()

  if fetched.invalid_login_attempts > 0:
    can_retry_at = exponential_backoff(fetched.invalid_login_attempts, EXPONENTIAL_BACKOFF_SCALE,
                                       fetched.last_invalid_login)

    if can_retry_at > now:
      retry_after = can_retry_at - now
      raise TooManyLoginAttemptsException('Too many login attempts.', retry_after.total_seconds())

  if (fetched.password_hash and
      hash_password(password, fetched.password_hash) == fetched.password_hash):
    if fetched.invalid_login_attempts > 0:
      fetched.invalid_login_attempts = 0
      fetched.save()

    return fetched

  fetched.invalid_login_attempts += 1
  fetched.last_invalid_login = now
  fetched.save()

  # We weren't able to authorize the user
  return None


def get_all_repo_users(namespace_name, repository_name):
  return (RepositoryPermission
          .select(User.username, User.email, User.robot, Role.name, RepositoryPermission)
          .join(User)
          .switch(RepositoryPermission)
          .join(Role)
          .switch(RepositoryPermission)
          .join(Repository)
          .join(Namespace, on=(Repository.namespace_user == Namespace.id))
          .where(Namespace.username == namespace_name, Repository.name == repository_name))


def get_all_repo_users_transitive_via_teams(namespace_name, repository_name):
  return (User
          .select()
          .distinct()
          .join(TeamMember)
          .join(Team)
          .join(RepositoryPermission)
          .join(Repository)
          .join(Namespace, on=(Repository.namespace_user == Namespace.id))
          .where(Namespace.username == namespace_name, Repository.name == repository_name))


def get_all_repo_users_transitive(namespace_name, repository_name):
  # Load the users found via teams and directly via permissions.
  via_teams = get_all_repo_users_transitive_via_teams(namespace_name, repository_name)
  directly = [perm.user for perm in get_all_repo_users(namespace_name, repository_name)]

  # Filter duplicates.
  user_set = set()

  def check_add(u):
    if u.username in user_set:
      return False

    user_set.add(u.username)
    return True

  return [user for user in list(directly) + list(via_teams) if check_add(user)]


def get_private_repo_count(username):
  return (Repository
          .select()
          .join(Visibility)
          .switch(Repository)
          .join(Namespace, on=(Repository.namespace_user == Namespace.id))
          .where(Namespace.username == username, Visibility.name == 'private')
          .count())


def get_active_users():
  return User.select().where(User.organization == False, User.robot == False)


def get_active_user_count():
  return get_active_users().count()


def get_robot_count():
  return User.select().where(User.robot == True).count()


def detach_external_login(user, service_name):
  try:
    service = LoginService.get(name=service_name)
  except LoginService.DoesNotExist:
    return

  FederatedLogin.delete().where(FederatedLogin.user == user,
                                FederatedLogin.service == service).execute()


def get_solely_admined_organizations(user_obj):
  """ Returns the organizations admined solely by the given user. """
  orgs = (User.select()
          .where(User.organization == True)
          .join(Team)
          .join(TeamRole)
          .where(TeamRole.name == 'admin')
          .switch(Team)
          .join(TeamMember)
          .where(TeamMember.user == user_obj)
          .distinct())

  # Filter to organizations where the user is the sole admin.
  solely_admined = []
  for org in orgs:
    admin_user_count = (TeamMember.select()
                        .join(Team)
                        .join(TeamRole)
                        .where(Team.organization == org, TeamRole.name == 'admin')
                        .switch(TeamMember)
                        .join(User)
                        .where(User.robot == False)
                        .distinct()
                        .count())

    if admin_user_count == 1:
      solely_admined.append(org)

  return solely_admined


def delete_user(user, queues, force=False):
  if not force and not user.organization:
    # Ensure that the user is not the sole admin for any organizations. If so, then the user
    # cannot be deleted before those organizations are deleted or reassigned.
    organizations = get_solely_admined_organizations(user)
    if len(organizations) > 0:
      message = 'Cannot delete %s as you are the only admin for organizations: ' % user.username
      for index, org in enumerate(organizations):
        if index > 0:
          message = message + ', '

        message = message + org.username

      raise DataModelException(message)

  # Delete all queue items for the user.
  for queue in queues:
    queue.delete_namespaced_items(user.username)

  # Delete any repositories under the user's namespace.
  for repo in list(Repository.select().where(Repository.namespace_user == user)):
    repository.purge_repository(user.username, repo.name)

  if user.organization:
    # Delete the organization's teams.
    for team in Team.select().where(Team.organization == user):
      team.delete_instance(recursive=True)

    # Delete any OAuth approvals and tokens associated with the user.
    for app in OAuthApplication.select().where(OAuthApplication.organization == user):
      app.delete_instance(recursive=True)
  else:
    # Remove the user from any teams in which they are a member.
    TeamMember.delete().where(TeamMember.user == user).execute()

  # Delete any repository buildtriggers where the user is the connected user.
  triggers = RepositoryBuildTrigger.select().where(RepositoryBuildTrigger.connected_user == user)
  for trigger in triggers:
    trigger.delete_instance(recursive=True, delete_nullable=False)

  # Null out any service key approvals. We technically lose information here, but its better than
  # falling and only occurs if a superuser is being deleted.
  ServiceKeyApproval.update(approver=None).where(ServiceKeyApproval.approver == user).execute()

  # Delete the user itself.
  user.delete_instance(recursive=True, delete_nullable=True)


def get_pull_credentials(robotname):
  try:
    robot = lookup_robot(robotname)
  except InvalidRobotException:
    return None

  try:
    login_info = FederatedLogin.get(user=robot)
  except FederatedLogin.DoesNotExist:
    return None

  return {
      'username': robot.username,
      'password': login_info.service_ident,
      'registry': '%s://%s/v1/' % (config.app_config['PREFERRED_URL_SCHEME'],
                                   config.app_config['SERVER_HOSTNAME']),
  }

def get_region_locations(user):
  """ Returns the locations defined as preferred storage for the given user. """
  query = UserRegion.select().join(ImageStorageLocation).where(UserRegion.user == user)
  return set([region.location.name for region in query])

def get_federated_logins(user_ids, service_name):
  """ Returns all federated logins for the given user ids under the given external service. """
  if not user_ids:
    return []

  return (FederatedLogin
          .select()
          .join(User)
          .switch(FederatedLogin)
          .join(LoginService)
          .where(FederatedLogin.user << user_ids,
                 LoginService.name == service_name))


class LoginWrappedDBUser(UserMixin):
  def __init__(self, user_uuid, db_user=None):
    self._uuid = user_uuid
    self._db_user = db_user

  def db_user(self):
    if not self._db_user:
      self._db_user = get_user_by_uuid(self._uuid)
    return self._db_user

  @property
  def is_authenticated(self):
    return self.db_user() is not None

  @property
  def is_active(self):
    return self.db_user().verified

  def get_id(self):
    return unicode(self._uuid)