# Copyright 21 May 2005 - (c) 2005 Jake Edge <jake@edge2.net>

# Copyright 2005-2007 Olivia Mackall <olivia@selenic.com>

#

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

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

import contextlib

import struct

import threading

from .i18n import _

from . import (

    encoding,

    error,

    pycompat,

    util,

    wireprototypes,

    wireprotov1server,

)

from .interfaces import util as interfaceutil

from .utils import (

    compression,

    stringutil,

)

stringio = util.stringio

urlerr = util.urlerr

urlreq = util.urlreq

HTTP_OK = 200

HGTYPE = b'application/mercurial-0.1'

HGTYPE2 = b'application/mercurial-0.2'

HGERRTYPE = b'application/hg-error'

SSHV1 = wireprototypes.SSHV1

def decodevaluefromheaders(req, headerprefix):

    """Decode a long value from multiple HTTP request headers.

    Returns the value as a bytes, not a str.

    """

    chunks = []

    i = 1

    while True:

        v = req.headers.get(b'%s-%d' % (headerprefix, i))

        if v is None:

            break

        chunks.append(pycompat.bytesurl(v))

        i += 1

    return b''.join(chunks)

@interfaceutil.implementer(wireprototypes.baseprotocolhandler)

class httpv1protocolhandler:

    def __init__(self, req, ui, checkperm):

        self._req = req

        self._ui = ui

        self._checkperm = checkperm

        self._protocaps = None

    @property

    def name(self):

        return b'http-v1'

    def getargs(self, args):

        knownargs = self._args()

        data = {}

        keys = args.split()

        for k in keys:

            if k == b'*':

                star = {}

                for key in knownargs.keys():

                    if key != b'cmd' and key not in keys:

                        star[key] = knownargs[key][0]

                data[b'*'] = star

            else:

                data[k] = knownargs[k][0]

        return [data[k] for k in keys]

    def _args(self):

        args = self._req.qsparams.asdictoflists()

        postlen = int(self._req.headers.get(b'X-HgArgs-Post', 0))

        if postlen:

            args.update(

                urlreq.parseqs(

                    self._req.bodyfh.read(postlen), keep_blank_values=True

                )

            )

            return args

        argvalue = decodevaluefromheaders(self._req, b'X-HgArg')

        args.update(urlreq.parseqs(argvalue, keep_blank_values=True))

        return args

    def getprotocaps(self):

        if self._protocaps is None:

            value = decodevaluefromheaders(self._req, b'X-HgProto')

            self._protocaps = set(value.split(b' '))

        return self._protocaps

    def getpayload(self):

        # Existing clients *always* send Content-Length.

        length = int(self._req.headers[b'Content-Length'])

        # If httppostargs is used, we need to read Content-Length

        # minus the amount that was consumed by args.

        length -= int(self._req.headers.get(b'X-HgArgs-Post', 0))

        return util.filechunkiter(self._req.bodyfh, limit=length)

    @contextlib.contextmanager

    def mayberedirectstdio(self):

        oldout = self._ui.fout

        olderr = self._ui.ferr

        out = util.stringio()

        try:

            self._ui.fout = out

            self._ui.ferr = out

            yield out

        finally:

            self._ui.fout = oldout

            self._ui.ferr = olderr

    def client(self):

        return b'remote:%s:%s:%s' % (

            self._req.urlscheme,

            urlreq.quote(self._req.remotehost or b''),

            urlreq.quote(self._req.remoteuser or b''),

        )

    def addcapabilities(self, repo, caps):

        caps.append(b'batch')

        caps.append(

            b'httpheader=%d' % repo.ui.configint(b'server', b'maxhttpheaderlen')

        )

        if repo.ui.configbool(b'experimental', b'httppostargs'):

            caps.append(b'httppostargs')

        # FUTURE advertise 0.2rx once support is implemented

        # FUTURE advertise minrx and mintx after consulting config option

        caps.append(b'httpmediatype=0.1rx,0.1tx,0.2tx')

        compengines = wireprototypes.supportedcompengines(

            repo.ui, compression.SERVERROLE

        )

        if compengines:

            comptypes = b','.join(

                urlreq.quote(e.wireprotosupport().name) for e in compengines

            )

            caps.append(b'compression=%s' % comptypes)

        return caps

    def checkperm(self, perm):

        return self._checkperm(perm)

# This method exists mostly so that extensions like remotefilelog can

# disable a kludgey legacy method only over http. As of early 2018,

# there are no other known users, so with any luck we can discard this

# hook if remotefilelog becomes a first-party extension.

def iscmd(cmd):

    return cmd in wireprotov1server.commands

def handlewsgirequest(rctx, req, res, checkperm):

    """Possibly process a wire protocol request.

    If the current request is a wire protocol request, the request is

    processed by this function.

    ``req`` is a ``parsedrequest`` instance.

    ``res`` is a ``wsgiresponse`` instance.

    Returns a bool indicating if the request was serviced. If set, the caller

    should stop processing the request, as a response has already been issued.

    """

    # Avoid cycle involving hg module.

    from .hgweb import common as hgwebcommon

    repo = rctx.repo

    # HTTP version 1 wire protocol requests are denoted by a "cmd" query

    # string parameter. If it isn't present, this isn't a wire protocol

    # request.

    if b'cmd' not in req.qsparams:

        return False

    cmd = req.qsparams[b'cmd']

    # The "cmd" request parameter is used by both the wire protocol and hgweb.

    # While not all wire protocol commands are available for all transports,

    # if we see a "cmd" value that resembles a known wire protocol command, we

    # route it to a protocol handler. This is better than routing possible

    # wire protocol requests to hgweb because it prevents hgweb from using

    # known wire protocol commands and it is less confusing for machine

    # clients.

    if not iscmd(cmd):

        return False

    # The "cmd" query string argument is only valid on the root path of the

    # repo. e.g. ``/?cmd=foo``, ``/repo?cmd=foo``. URL paths within the repo

    # like ``/blah?cmd=foo`` are not allowed. So don't recognize the request

    # in this case. We send an HTTP 404 for backwards compatibility reasons.

    if req.dispatchpath:

        res.status = hgwebcommon.statusmessage(404)

        res.headers[b'Content-Type'] = HGTYPE

        # TODO This is not a good response to issue for this request. This

        # is mostly for BC for now.

        res.setbodybytes(b'0\n%s\n' % b'Not Found')

        return True

    proto = httpv1protocolhandler(

        req, repo.ui, lambda perm: checkperm(rctx, req, perm)

    )

    # The permissions checker should be the only thing that can raise an

    # ErrorResponse. It is kind of a layer violation to catch an hgweb

    # exception here. So consider refactoring into a exception type that

    # is associated with the wire protocol.

    try:

        _callhttp(repo, req, res, proto, cmd)

    except hgwebcommon.ErrorResponse as e:

        for k, v in e.headers:

            res.headers[k] = v

        res.status = hgwebcommon.statusmessage(

            e.code, stringutil.forcebytestr(e)

        )

        # TODO This response body assumes the failed command was

        # "unbundle." That assumption is not always valid.

        res.setbodybytes(b'0\n%s\n' % stringutil.forcebytestr(e))

    return True

def _httpresponsetype(ui, proto, prefer_uncompressed):

    """Determine the appropriate response type and compression settings.

    Returns a tuple of (mediatype, compengine, engineopts).

    """

    # Determine the response media type and compression engine based

    # on the request parameters.

    if b'0.2' in proto.getprotocaps():

        # All clients are expected to support uncompressed data.

        if prefer_uncompressed:

            return HGTYPE2, compression._noopengine(), {}

        # Now find an agreed upon compression format.

        compformats = wireprotov1server.clientcompressionsupport(proto)

        for engine in wireprototypes.supportedcompengines(

            ui, compression.SERVERROLE

        ):

            if engine.wireprotosupport().name in compformats:

                opts = {}

                level = ui.configint(b'server', b'%slevel' % engine.name())

                if level is not None:

                    opts[b'level'] = level

                return HGTYPE2, engine, opts

        # No mutually supported compression format. Fall back to the

        # legacy protocol.

    # Don't allow untrusted settings because disabling compression or

    # setting a very high compression level could lead to flooding

    # the server's network or CPU.

    opts = {b'level': ui.configint(b'server', b'zliblevel')}

    return HGTYPE, util.compengines[b'zlib'], opts

def _callhttp(repo, req, res, proto, cmd):

    # Avoid cycle involving hg module.

    from .hgweb import common as hgwebcommon

    def genversion2(gen, engine, engineopts):

        # application/mercurial-0.2 always sends a payload header

        # identifying the compression engine.

        name = engine.wireprotosupport().name

        assert 0 < len(name) < 256

        yield struct.pack(b'B', len(name))

        yield name

        for chunk in gen:

            yield chunk

    def setresponse(code, contenttype, bodybytes=None, bodygen=None):

        if code == HTTP_OK:

            res.status = b'200 Script output follows'

        else:

            res.status = hgwebcommon.statusmessage(code)

        res.headers[b'Content-Type'] = contenttype

        if bodybytes is not None:

            res.setbodybytes(bodybytes)

        if bodygen is not None:

            res.setbodygen(bodygen)

    if not wireprotov1server.commands.commandavailable(cmd, proto):

        setresponse(

            HTTP_OK,

            HGERRTYPE,

            _(

                b'requested wire protocol command is not available over '

                b'HTTP'

            ),

        )

        return

    proto.checkperm(wireprotov1server.commands[cmd].permission)

    rsp = wireprotov1server.dispatch(repo, proto, cmd)

    if isinstance(rsp, bytes):

        setresponse(HTTP_OK, HGTYPE, bodybytes=rsp)

    elif isinstance(rsp, wireprototypes.bytesresponse):

        setresponse(HTTP_OK, HGTYPE, bodybytes=rsp.data)

    elif isinstance(rsp, wireprototypes.streamreslegacy):

        setresponse(HTTP_OK, HGTYPE, bodygen=rsp.gen)

    elif isinstance(rsp, wireprototypes.streamres):

        gen = rsp.gen

        # This code for compression should not be streamres specific. It

        # is here because we only compress streamres at the moment.

        mediatype, engine, engineopts = _httpresponsetype(

            repo.ui, proto, rsp.prefer_uncompressed

        )

        gen = engine.compressstream(gen, engineopts)

        if mediatype == HGTYPE2:

            gen = genversion2(gen, engine, engineopts)

        setresponse(HTTP_OK, mediatype, bodygen=gen)

    elif isinstance(rsp, wireprototypes.pushres):

        rsp = b'%d\n%s' % (rsp.res, rsp.output)

        setresponse(HTTP_OK, HGTYPE, bodybytes=rsp)

    elif isinstance(rsp, wireprototypes.pusherr):

        rsp = b'0\n%s\n' % rsp.res

        res.drain = True

        setresponse(HTTP_OK, HGTYPE, bodybytes=rsp)

    elif isinstance(rsp, wireprototypes.ooberror):

        setresponse(HTTP_OK, HGERRTYPE, bodybytes=rsp.message)

    else:

        raise error.ProgrammingError(b'hgweb.protocol internal failure', rsp)

def _sshv1respondbytes(fout, value):

    """Send a bytes response for protocol version 1."""

    fout.write(b'%d\n' % len(value))

    fout.write(value)

    fout.flush()

def _sshv1respondstream(fout, source):

    write = fout.write

    for chunk in source.gen:

        write(chunk)

    fout.flush()

def _sshv1respondooberror(fout, ferr, rsp):

    ferr.write(b'%s\n-\n' % rsp)

    ferr.flush()

    fout.write(b'\n')

    fout.flush()

@interfaceutil.implementer(wireprototypes.baseprotocolhandler)

class sshv1protocolhandler:

    """Handler for requests services via version 1 of SSH protocol."""