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

# Copyright 2005-2007 Matt Mackall <mpm@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.

from __future__ import absolute_import

import abc

import cgi

import struct

import sys

from .i18n import _

from . import (

    encoding,

    error,

    hook,

    pycompat,

    util,

    wireproto,

)

stringio = util.stringio

urlerr = util.urlerr

urlreq = util.urlreq

HTTP_OK = 200

HGTYPE = 'application/mercurial-0.1'

HGTYPE2 = 'application/mercurial-0.2'

HGERRTYPE = 'application/hg-error'

# Names of the SSH protocol implementations.

SSHV1 = 'ssh-v1'

# This is advertised over the wire. Incremental the counter at the end

# to reflect BC breakages.

SSHV2 = 'exp-ssh-v2-0001'

class abstractserverproto(object):

    """abstract class that summarizes the protocol API

    Used as reference and documentation.

    """

    __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 getfile(self, fp):

        """write the whole content of a file into a file like object

        The file is in the form::

            (<chunk-size>\n<chunk>)+0\n

        chunk size is the ascii version of the int.

        """

    @abc.abstractmethod

    def redirect(self):

        """may setup interception for stdout and stderr

        See also the `restore` method."""

    # If the `redirect` function does install interception, the `restore`

    # function MUST be defined. If interception is not used, this function

    # MUST NOT be defined.

    #

    # left commented here on purpose

    #

    #def restore(self):

    #    """reinstall previous stdout and stderr and return intercepted stdout

    #    """

    #    raise NotImplementedError()

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

    prefix = headerprefix.upper().replace(r'-', r'_')

    while True:

        v = req.env.get(r'HTTP_%s_%d' % (prefix, i))

        if v is None:

            break

        chunks.append(pycompat.bytesurl(v))

        i += 1

    return ''.join(chunks)

class webproto(abstractserverproto):

    def __init__(self, req, ui):

        self._req = req

        self._ui = ui

    @property

    def name(self):

        return 'http'

    def getargs(self, args):

        knownargs = self._args()

        data = {}

        keys = args.split()

        for k in keys:

            if k == '*':

                star = {}

                for key in knownargs.keys():

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

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

                data['*'] = star

            else:

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

        return [data[k] for k in keys]

    def _args(self):

        args = util.rapply(pycompat.bytesurl, self._req.form.copy())

        postlen = int(self._req.env.get(r'HTTP_X_HGARGS_POST', 0))

        if postlen:

            args.update(cgi.parse_qs(

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

            return args

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

        args.update(cgi.parse_qs(argvalue, keep_blank_values=True))

        return args

    def getfile(self, fp):

        length = int(self._req.env[r'CONTENT_LENGTH'])

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

        # minus the amount that was consumed by args.

        length -= int(self._req.env.get(r'HTTP_X_HGARGS_POST', 0))

        for s in util.filechunkiter(self._req, limit=length):

            fp.write(s)

    def redirect(self):

        self._oldio = self._ui.fout, self._ui.ferr

        self._ui.ferr = self._ui.fout = stringio()

    def restore(self):

        val = self._ui.fout.getvalue()

        self._ui.ferr, self._ui.fout = self._oldio

        return val

    def _client(self):

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

            self._req.env.get('wsgi.url_scheme') or 'http',

            urlreq.quote(self._req.env.get('REMOTE_HOST', '')),

            urlreq.quote(self._req.env.get('REMOTE_USER', '')))

    def responsetype(self, 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.

        protocaps = decodevaluefromheaders(self._req, r'X-HgProto').split(' ')

        if '0.2' in protocaps:

            # All clients are expected to support uncompressed data.

            if prefer_uncompressed:

                return HGTYPE2, util._noopengine(), {}

            # Default as defined by wire protocol spec.

            compformats = ['zlib', 'none']

            for cap in protocaps:

                if cap.startswith('comp='):

                    compformats = cap[5:].split(',')

                    break

            # Now find an agreed upon compression format.

            for engine in wireproto.supportedcompengines(self._ui, self,

                                                         util.SERVERROLE):

                if engine.wireprotosupport().name in compformats:

                    opts = {}

                    level = self._ui.configint('server',

                                              '%slevel' % engine.name())

                    if level is not None:

                        opts['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 = {'level': self._ui.configint('server', 'zliblevel')}

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

def iscmd(cmd):

    return cmd in wireproto.commands

def parsehttprequest(repo, req, query):

    """Parse the HTTP request for a wire protocol request.

    If the current request appears to be a wire protocol request, this

    function returns a dict with details about that request, including

    an ``abstractprotocolserver`` instance suitable for handling the

    request. Otherwise, ``None`` is returned.

    ``req`` is a ``wsgirequest`` instance.

    """

    # 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 r'cmd' not in req.form:

        return None

    cmd = pycompat.sysbytes(req.form[r'cmd'][0])

    # 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 cmd not in wireproto.commands:

        return None

    proto = webproto(req, repo.ui)

    return {

        'cmd': cmd,

        'proto': proto,

        'dispatch': lambda: _callhttp(repo, req, proto, cmd),

    }

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

    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', len(name))

        yield name

        for chunk in gen:

            yield chunk

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

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

        req.respond(HTTP_OK, HGERRTYPE,

                    body=_('requested wire protocol command is not available '

                           'over HTTP'))

        return []

    if isinstance(rsp, bytes):

        req.respond(HTTP_OK, HGTYPE, body=rsp)

        return []

    elif isinstance(rsp, wireproto.streamres_legacy):

        gen = rsp.gen

        req.respond(HTTP_OK, HGTYPE)

        return gen

    elif isinstance(rsp, wireproto.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 = proto.responsetype(

            rsp.prefer_uncompressed)

        gen = engine.compressstream(gen, engineopts)

        if mediatype == HGTYPE2:

            gen = genversion2(gen, engine, engineopts)

        req.respond(HTTP_OK, mediatype)

        return gen

    elif isinstance(rsp, wireproto.pushres):

        val = proto.restore()

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

        req.respond(HTTP_OK, HGTYPE, body=rsp)

        return []

    elif isinstance(rsp, wireproto.pusherr):

        # drain the incoming bundle

        req.drain()

        proto.restore()

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

        req.respond(HTTP_OK, HGTYPE, body=rsp)

        return []

    elif isinstance(rsp, wireproto.ooberror):

        rsp = rsp.message

        req.respond(HTTP_OK, HGERRTYPE, body=rsp)

        return []

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

class sshserver(abstractserverproto):

    def __init__(self, ui, repo):

        self._ui = ui

        self._repo = repo

        self._fin = ui.fin

        self._fout = ui.fout

        hook.redirect(True)

        ui.fout = repo.ui.fout = ui.ferr

        # Prevent insertion/deletion of CRs

        util.setbinary(self._fin)

        util.setbinary(self._fout)

    @property

    def name(self):

        return 'ssh'

    def getargs(self, args):

        data = {}

        keys = args.split()

        for n in xrange(len(keys)):

            argline = self._fin.readline()[:-1]

            arg, l = argline.split()

            if arg not in keys:

                raise error.Abort(_("unexpected parameter %r") % arg)

            if arg == '*':

                star = {}

                for k in xrange(int(l)):

                    argline = self._fin.readline()[:-1]

                    arg, l = argline.split()

                    val = self._fin.read(int(l))

                    star[arg] = val

                data['*'] = star

            else:

                val = self._fin.read(int(l))

                data[arg] = val

        return [data[k] for k in keys]

    def getfile(self, fpout):

        self._sendresponse('')

        count = int(self._fin.readline())

        while count:

            fpout.write(self._fin.read(count))

            count = int(self._fin.readline())

    def redirect(self):

        pass

    def _sendresponse(self, v):

        self._fout.write("%d\n" % len(v))

        self._fout.write(v)

        self._fout.flush()

    def _sendstream(self, source):

        write = self._fout.write

        for chunk in source.gen:

            write(chunk)