# Copyright (c) "Neo4j"
# Neo4j Sweden AB [https://neo4j.com]
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     https://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.


""" Base classes and helpers.
"""


from __future__ import annotations

import abc
import typing as t
from urllib.parse import (
    parse_qs,
    urlparse,
)

from ._meta import deprecated
from .exceptions import ConfigurationError


if t.TYPE_CHECKING:
    import typing_extensions as te
    from typing_extensions import Protocol as _Protocol

    from .addressing import Address
else:
    _Protocol = object


READ_ACCESS: te.Final[str] = "READ"
WRITE_ACCESS: te.Final[str] = "WRITE"

DRIVER_BOLT: te.Final[str] = "DRIVER_BOLT"
DRIVER_NEO4J: te.Final[str] = "DRIVER_NEO4J"

SECURITY_TYPE_NOT_SECURE: te.Final[str] = "SECURITY_TYPE_NOT_SECURE"
SECURITY_TYPE_SELF_SIGNED_CERTIFICATE: te.Final[str] = \
    "SECURITY_TYPE_SELF_SIGNED_CERTIFICATE"
SECURITY_TYPE_SECURE: te.Final[str] = "SECURITY_TYPE_SECURE"

URI_SCHEME_BOLT: te.Final[str] = "bolt"
URI_SCHEME_BOLT_SELF_SIGNED_CERTIFICATE: te.Final[str] = "bolt+ssc"
URI_SCHEME_BOLT_SECURE: te.Final[str] = "bolt+s"

URI_SCHEME_NEO4J: te.Final[str] = "neo4j"
URI_SCHEME_NEO4J_SELF_SIGNED_CERTIFICATE: te.Final[str] = "neo4j+ssc"
URI_SCHEME_NEO4J_SECURE: te.Final[str] = "neo4j+s"

URI_SCHEME_BOLT_ROUTING: te.Final[str] = "bolt+routing"

# TODO: 6.0 - remove TRUST constants
TRUST_SYSTEM_CA_SIGNED_CERTIFICATES: te.Final[str] = \
    "TRUST_SYSTEM_CA_SIGNED_CERTIFICATES"  # Default
TRUST_ALL_CERTIFICATES: te.Final[str] = "TRUST_ALL_CERTIFICATES"

SYSTEM_DATABASE: te.Final[str] = "system"
DEFAULT_DATABASE: te.Final[None] = None  # Must be a non string hashable value


# TODO: This class is not tested
class Auth:
    """Container for auth details.

    :param scheme: specifies the type of authentication, examples: "basic",
                   "kerberos"
    :type scheme: str | None
    :param principal: specifies who is being authenticated
    :type principal: str | None
    :param credentials: authenticates the principal
    :type credentials: str | None
    :param realm: specifies the authentication provider
    :type realm: str | None
    :param parameters: extra key word parameters passed along to the
                       authentication provider
    :type parameters: typing.Any
    """

    def __init__(
        self,
        scheme: t.Optional[str],
        principal: t.Optional[str],
        credentials: t.Optional[str],
        realm: t.Optional[str] = None,
        **parameters: t.Any
    ) -> None:
        self.scheme = scheme
        # Neo4j servers pre 4.4 require the principal field to always be
        # present. Therefore, we transmit it even if it's an empty sting.
        if principal is not None:
            self.principal = principal
        if credentials:
            self.credentials = credentials
        if realm:
            self.realm = realm
        if parameters:
            self.parameters = parameters

    def __eq__(self, other: t.Any) -> bool:
        if not isinstance(other, Auth):
            return NotImplemented
        return vars(self) == vars(other)


# For backwards compatibility
AuthToken = Auth

if t.TYPE_CHECKING:
    _TAuth = t.Union[t.Tuple[t.Any, t.Any], Auth, None]


def basic_auth(
    user: str, password: str, realm: t.Optional[str] = None
) -> Auth:
    """Generate a basic auth token for a given user and password.

    This will set the scheme to "basic" for the auth token.

    :param user: user name, this will set the
    :param password: current password, this will set the credentials
    :param realm: specifies the authentication provider

    :returns: auth token for use with :meth:`GraphDatabase.driver` or
        :meth:`AsyncGraphDatabase.driver`
    """
    return Auth("basic", user, password, realm)


def kerberos_auth(base64_encoded_ticket: str) -> Auth:
    """Generate a kerberos auth token with the base64 encoded ticket.

    This will set the scheme to "kerberos" for the auth token.

    :param base64_encoded_ticket: a base64 encoded service ticket, this will set
                                  the credentials

    :returns: auth token for use with :meth:`GraphDatabase.driver` or
        :meth:`AsyncGraphDatabase.driver`
    """
    return Auth("kerberos", "", base64_encoded_ticket)


def bearer_auth(base64_encoded_token: str) -> Auth:
    """Generate an auth token for Single-Sign-On providers.

    This will set the scheme to "bearer" for the auth token.

    :param base64_encoded_token: a base64 encoded authentication token generated
                                 by a Single-Sign-On provider.

    :returns: auth token for use with :meth:`GraphDatabase.driver` or
        :meth:`AsyncGraphDatabase.driver`
    """
    return Auth("bearer", None, base64_encoded_token)


def custom_auth(
    principal: t.Optional[str],
    credentials: t.Optional[str],
    realm: t.Optional[str],
    scheme: t.Optional[str],
    **parameters: t.Any
) -> Auth:
    """Generate a custom auth token.

    :param principal: specifies who is being authenticated
    :param credentials: authenticates the principal
    :param realm: specifies the authentication provider
    :param scheme: specifies the type of authentication
    :param parameters: extra key word parameters passed along to the
                       authentication provider

    :returns: auth token for use with :meth:`GraphDatabase.driver` or
        :meth:`AsyncGraphDatabase.driver`
    """
    return Auth(scheme, principal, credentials, realm, **parameters)


# TODO: 6.0 - remove this class
@deprecated("Use the `Bookmarks` class instead.")
class Bookmark:
    """A Bookmark object contains an immutable list of bookmark string values.

    :param values: ASCII string values

    .. deprecated:: 5.0
        `Bookmark` will be removed in version 6.0.
        Use :class:`Bookmarks` instead.
    """
    def __init__(self, *values: str) -> None:
        if values:
            bookmarks = []
            for ix in values:
                try:
                    if ix:
                        ix.encode("ascii")
                        bookmarks.append(ix)
                except UnicodeEncodeError as e:
                    raise ValueError("The value {} is not ASCII".format(ix))
            self._values = frozenset(bookmarks)
        else:
            self._values = frozenset()

    def __repr__(self) -> str:
        """
        :returns: repr string with sorted values
        """
        return "<Bookmark values={{{}}}>".format(", ".join(["'{}'".format(ix) for ix in sorted(self._values)]))

    def __bool__(self) -> bool:
        return bool(self._values)

    @property
    def values(self) -> frozenset:
        """
        :returns: immutable list of bookmark string values
        """
        return self._values


class Bookmarks:
    """Container for an immutable set of bookmark string values.

    Bookmarks are used to causally chain sessions.
    See :meth:`Session.last_bookmarks` or :meth:`AsyncSession.last_bookmarks`
    for more information.

    Use addition to combine multiple Bookmarks objects::

        bookmarks3 = bookmarks1 + bookmarks2
    """

    def __init__(self):
        self._raw_values = frozenset()

    def __repr__(self) -> str:
        """
        :returns: repr string with sorted values
        """
        return "<Bookmarks values={{{}}}>".format(
            ", ".join(map(repr, sorted(self._raw_values)))
        )

    def __bool__(self) -> bool:
        """True if there are bookmarks in the container."""
        return bool(self._raw_values)

    def __add__(self, other: Bookmarks) -> Bookmarks:
        """Add multiple containers together."""
        if isinstance(other, Bookmarks):
            if not other:
                return self
            ret = self.__class__()
            ret._raw_values = self._raw_values | other._raw_values
            return ret
        return NotImplemented

    @property
    def raw_values(self) -> t.FrozenSet[str]:
        """The raw bookmark values.

        You should not need to access them unless you want to serialize
        bookmarks.

        :returns: immutable list of bookmark string values
        :rtype: frozenset[str]
        """
        return self._raw_values

    @classmethod
    def from_raw_values(cls, values: t.Iterable[str]) -> Bookmarks:
        """Create a Bookmarks object from a list of raw bookmark string values.

        You should not need to use this method unless you want to deserialize
        bookmarks.

        :param values: ASCII string values (raw bookmarks)
        :type values: Iterable[str]
        """
        obj = cls()
        bookmarks = []
        for value in values:
            if not isinstance(value, str):
                raise TypeError("Raw bookmark values must be str. "
                                "Found {}".format(type(value)))
            try:
                value.encode("ascii")
            except UnicodeEncodeError as e:
                raise ValueError(f"The value {value} is not ASCII") from e
            bookmarks.append(value)
        obj._raw_values = frozenset(bookmarks)
        return obj


class ServerInfo:
    """ Represents a package of information relating to a Neo4j server.
    """

    def __init__(self, address: Address, protocol_version: Version):
        self._address = address
        self._protocol_version = protocol_version
        self._metadata: dict = {}

    @property
    def address(self) -> Address:
        """ Network address of the remote server.
        """
        return self._address

    @property
    def protocol_version(self) -> Version:
        """ Bolt protocol version with which the remote server
        communicates. This is returned as a :class:`.Version`
        object, which itself extends a simple 2-tuple of
        (major, minor) integers.
        """
        return self._protocol_version

    @property
    def agent(self) -> str:
        """ Server agent string by which the remote server identifies
        itself.
        """
        return str(self._metadata.get("server"))

    @property  # type: ignore
    @deprecated("The connection id is considered internal information "
                "and will no longer be exposed in future versions.")
    def connection_id(self):
        """ Unique identifier for the remote server connection.
        """
        return self._metadata.get("connection_id")

    def update(self, metadata: dict) -> None:
        """ Update server information with extra metadata. This is
        typically drawn from the metadata received after successful
        connection initialisation.
        """
        self._metadata.update(metadata)


class Version(tuple):

    def __new__(cls, *v):
        return super().__new__(cls, v)

    def __repr__(self):
        return "{}{}".format(self.__class__.__name__, super().__repr__())

    def __str__(self):
        return ".".join(map(str, self))

    def to_bytes(self) -> bytes:
        b = bytearray(4)
        for i, v in enumerate(self):
            if not 0 <= i < 2:
                raise ValueError("Too many version components")
            if isinstance(v, list):
                b[-i - 1] = int(v[0] % 0x100)
                b[-i - 2] = int((v[0] - v[-1]) % 0x100)
            else:
                b[-i - 1] = int(v % 0x100)
        return bytes(b)

    @classmethod
    def from_bytes(cls, b: bytes) -> Version:
        b = bytearray(b)
        if len(b) != 4:
            raise ValueError("Byte representation must be exactly four bytes")
        if b[0] != 0 or b[1] != 0:
            raise ValueError("First two bytes must contain zero")
        return Version(b[-1], b[-2])


class BookmarkManager(_Protocol, metaclass=abc.ABCMeta):
    """Class to manage bookmarks throughout the driver's lifetime.

    Neo4j clusters are eventually consistent, meaning that there is no
    guarantee a query will be able to read changes made by a previous query.
    For cases where such a guarantee is necessary, the server provides
    bookmarks to the client. A bookmark is an abstract token that represents
    some state of the database. By passing one or multiple bookmarks along
    with a query, the server will make sure that the query will not get
    executed before the represented state(s) (or a later state) have been
    established.

    The bookmark manager is an interface used by the driver for keeping
    track of the bookmarks and this way keeping sessions automatically
    consistent. Configure the driver to use a specific bookmark manager with
    :ref:`bookmark-manager-ref`.

    This class is just an abstract base class that defines the required
    interface. Create a child class to implement a specific bookmark manager
    or make use of the default implementation provided by the driver through
    :meth:`.GraphDatabase.bookmark_manager()`.

    .. note::
        All methods must be concurrency safe.

    .. versionadded:: 5.0

    .. versionchanged:: 5.3
        The bookmark manager no longer tracks bookmarks per database.
        This effectively changes the signature of almost all bookmark
        manager related methods:

        * :meth:`.update_bookmarks` has no longer a ``database`` argument.
        * :meth:`.get_bookmarks` has no longer a ``database`` argument.
        * The ``get_all_bookmarks`` method was removed.
        * The ``forget`` method was removed.

    .. versionchanged:: 5.8 Stabilized from experimental.
    """

    @abc.abstractmethod
    def update_bookmarks(
        self, previous_bookmarks: t.Collection[str],
        new_bookmarks: t.Collection[str]
    ) -> None:
        """Handle bookmark updates.

        :param previous_bookmarks:
            The bookmarks used at the start of a transaction
        :param new_bookmarks:
            The new bookmarks retrieved at the end of a transaction
        """
        ...

    @abc.abstractmethod
    def get_bookmarks(self) -> t.Collection[str]:
        """Return the bookmarks stored in the bookmark manager.

        :returns: The bookmarks for the given database
        """
        ...


class AsyncBookmarkManager(_Protocol, metaclass=abc.ABCMeta):
    """Same as :class:`.BookmarkManager` but with async methods.

    The driver comes with a default implementation of the async bookmark
    manager accessible through :attr:`.AsyncGraphDatabase.bookmark_manager()`.

    .. versionadded:: 5.0

    .. versionchanged:: 5.3
        See :class:`.BookmarkManager` for changes.

    .. versionchanged:: 5.8 Stabilized from experimental.
    """

    @abc.abstractmethod
    async def update_bookmarks(
        self, previous_bookmarks: t.Collection[str],
        new_bookmarks: t.Collection[str]
    ) -> None:
        ...

    update_bookmarks.__doc__ = BookmarkManager.update_bookmarks.__doc__

    @abc.abstractmethod
    async def get_bookmarks(self) -> t.Collection[str]:
        ...

    get_bookmarks.__doc__ = BookmarkManager.get_bookmarks.__doc__


def parse_neo4j_uri(uri):
    parsed = urlparse(uri)

    if parsed.username:
        raise ConfigurationError("Username is not supported in the URI")

    if parsed.password:
        raise ConfigurationError("Password is not supported in the URI")

    if parsed.scheme == URI_SCHEME_BOLT_ROUTING:
        raise ConfigurationError("Uri scheme {!r} have been renamed. Use {!r}".format(parsed.scheme, URI_SCHEME_NEO4J))
    elif parsed.scheme == URI_SCHEME_BOLT:
        driver_type = DRIVER_BOLT
        security_type = SECURITY_TYPE_NOT_SECURE
    elif parsed.scheme == URI_SCHEME_BOLT_SELF_SIGNED_CERTIFICATE:
        driver_type = DRIVER_BOLT
        security_type = SECURITY_TYPE_SELF_SIGNED_CERTIFICATE
    elif parsed.scheme == URI_SCHEME_BOLT_SECURE:
        driver_type = DRIVER_BOLT
        security_type = SECURITY_TYPE_SECURE
    elif parsed.scheme == URI_SCHEME_NEO4J:
        driver_type = DRIVER_NEO4J
        security_type = SECURITY_TYPE_NOT_SECURE
    elif parsed.scheme == URI_SCHEME_NEO4J_SELF_SIGNED_CERTIFICATE:
        driver_type = DRIVER_NEO4J
        security_type = SECURITY_TYPE_SELF_SIGNED_CERTIFICATE
    elif parsed.scheme == URI_SCHEME_NEO4J_SECURE:
        driver_type = DRIVER_NEO4J
        security_type = SECURITY_TYPE_SECURE
    else:
        raise ConfigurationError("URI scheme {!r} is not supported. Supported URI schemes are {}. Examples: bolt://host[:port] or neo4j://host[:port][?routing_context]".format(
            parsed.scheme,
            [
                URI_SCHEME_BOLT,
                URI_SCHEME_BOLT_SELF_SIGNED_CERTIFICATE,
                URI_SCHEME_BOLT_SECURE,
                URI_SCHEME_NEO4J,
                URI_SCHEME_NEO4J_SELF_SIGNED_CERTIFICATE,
                URI_SCHEME_NEO4J_SECURE
            ]
        ))

    return driver_type, security_type, parsed


def check_access_mode(access_mode):
    if access_mode is None:
        return WRITE_ACCESS
    if access_mode not in (READ_ACCESS, WRITE_ACCESS):
        msg = "Unsupported access mode {}".format(access_mode)
        raise ConfigurationError(msg)

    return access_mode


def parse_routing_context(query):
    """ Parse the query portion of a URI to generate a routing context dictionary.
    """
    if not query:
        return {}

    context = {}
    parameters = parse_qs(query, True)
    for key in parameters:
        value_list = parameters[key]
        if len(value_list) != 1:
            raise ConfigurationError("Duplicated query parameters with key '%s', value '%s' found in query string '%s'" % (key, value_list, query))
        value = value_list[0]
        if not value:
            raise ConfigurationError("Invalid parameters:'%s=%s' in query string '%s'." % (key, value, query))
        context[key] = value

    return context