# Copyright 2018 Gregory Szorc <gregory.szorc@gmail.com>

#

# This software may be used and distributed according to the terms of the

# GNU General Public License version 2 or any later version.

from __future__ import absolute_import

import abc

# Names of the SSH protocol implementations.

SSHV1 = 'ssh-v1'

# These are advertised over the wire. Increment the counters at the end

# to reflect BC breakages.

SSHV2 = 'exp-ssh-v2-0001'

HTTPV2 = 'exp-http-v2-0001'

# All available wire protocol transports.

TRANSPORTS = {

    SSHV1: {

        'transport': 'ssh',

        'version': 1,

    },

    SSHV2: {

        'transport': 'ssh',

        'version': 2,

    },

    'http-v1': {

        'transport': 'http',

        'version': 1,

    },

    HTTPV2: {

        'transport': 'http',

        'version': 2,

    }

}

class bytesresponse(object):

    """A wire protocol response consisting of raw bytes."""

    def __init__(self, data):

        self.data = data

class ooberror(object):

    """wireproto reply: failure of a batch of operation

    Something failed during a batch call. The error message is stored in

    `self.message`.

    """

    def __init__(self, message):

        self.message = message

class pushres(object):

    """wireproto reply: success with simple integer return

    The call was successful and returned an integer contained in `self.res`.

    """

    def __init__(self, res, output):

        self.res = res

        self.output = output

class pusherr(object):

    """wireproto reply: failure

    The call failed. The `self.res` attribute contains the error message.

    """

    def __init__(self, res, output):

        self.res = res

        self.output = output

class streamres(object):

    """wireproto reply: binary stream

    The call was successful and the result is a stream.

    Accepts a generator containing chunks of data to be sent to the client.

    ``prefer_uncompressed`` indicates that the data is expected to be

    uncompressable and that the stream should therefore use the ``none``

    engine.

    """

    def __init__(self, gen=None, prefer_uncompressed=False):

        self.gen = gen

        self.prefer_uncompressed = prefer_uncompressed

class streamreslegacy(object):

    """wireproto reply: uncompressed binary stream

    The call was successful and the result is a stream.

    Accepts a generator containing chunks of data to be sent to the client.

    Like ``streamres``, but sends an uncompressed data for "version 1" clients

    using the application/mercurial-0.1 media type.

    """

    def __init__(self, gen=None):

        self.gen = gen

class baseprotocolhandler(object):

    """Abstract base class for wire protocol handlers.

    A wire protocol handler serves as an interface between protocol command

    handlers and the wire protocol transport layer. Protocol handlers provide

    methods to read command arguments, redirect stdio for the duration of

    the request, handle response types, etc.

    """

    __metaclass__ = abc.ABCMeta

    @abc.abstractproperty

    def name(self):

        """The name of the protocol implementation.

        Used for uniquely identifying the transport type.

        """

    @abc.abstractmethod

    def getargs(self, args):

        """return the value for arguments in <args>

        returns a list of values (same order as <args>)"""

    @abc.abstractmethod

    def forwardpayload(self, fp):

        """Read the raw payload and forward to a file.

        The payload is read in full before the function returns.

        """

    @abc.abstractmethod

    def mayberedirectstdio(self):

        """Context manager to possibly redirect stdio.

        The context manager yields a file-object like object that receives

        stdout and stderr output when the context manager is active. Or it

        yields ``None`` if no I/O redirection occurs.

        The intent of this context manager is to capture stdio output

        so it may be sent in the response. Some transports support streaming

        stdio to the client in real time. For these transports, stdio output

        won't be captured.

        """

    @abc.abstractmethod

    def client(self):

        """Returns a string representation of this client (as bytes)."""

    @abc.abstractmethod

    def addcapabilities(self, repo, caps):

        """Adds advertised capabilities specific to this protocol.

        Receives the list of capabilities collected so far.

        Returns a list of capabilities. The passed in argument can be returned.

        """

    @abc.abstractmethod

    def checkperm(self, perm):

        """Validate that the client has permissions to perform a request.

        The argument is the permission required to proceed. If the client

        doesn't have that permission, the exception should raise or abort

        in a protocol specific manner.

        """