# vim: tabstop=4 shiftwidth=4 softtabstop=4

# Copyright 2014 IBM Corporation
#
# 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
#
#     http://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.
# ALl rights reserved

# This is the socket api layer.
# It implement unix and tls sockets
# 

import atexit
import errno
import os
import pwd
import stat
import struct
import sys
import traceback

import eventlet.green.socket as socket
import eventlet.green.ssl as ssl
import eventlet

import confluentd.auth as auth
import confluent.tlvdata as tlvdata
import confluentd.consoleserver as consoleserver
import confluentd.config.configmanager as configmanager
import confluentd.exceptions as exc
import confluentd.log as log
import confluentd.core as pluginapi


tracelog = None
auditlog = None
try:
    SO_PEERCRED = socket.SO_PEERCRED
except AttributeError:
    import platform
    if "ppc64" in platform.machine():
        SO_PEERCRED = 21
    else:
        SO_PEERCRED = 17


class ClientConsole(object):
    def __init__(self, client):
        self.client = client
        self.xmit = False
        self.pendingdata = []

    def sendall(self, data):
        if not self.xmit:
            self.pendingdata.append(data)
            return
        send_data(self.client, data)

    def startsending(self):
        self.xmit = True
        for datum in self.pendingdata:
            send_data(self.client, datum)
        self.pendingdata = None


def send_data(connection, data):
    try:
        tlvdata.send(connection, data)
    except IOError as ie:
        if ie.errno != errno.EPIPE:
            raise


def sessionhdl(connection, authname, skipauth=False):
    # For now, trying to test the console stuff, so let's just do n4.
    authenticated = False
    authdata = None
    cfm = None
    if skipauth:
        authenticated = True
        cfm = configmanager.ConfigManager(tenant=None)
    elif authname:
        authdata = auth.authorize(authname, element=None)
        if authdata is not None:
            cfm = authdata[1]
            authenticated = True
    send_data(connection, "Confluent -- v0 --")
    while not authenticated:  # prompt for name and passphrase
        send_data(connection, {'authpassed': 0})
        response = tlvdata.recv(connection)
        authname = response['username']
        passphrase = response['password']
        # note(jbjohnso): here, we need to authenticate, but not
        # authorize a user.  When authorization starts understanding
        # element path, that authorization will need to be called
        # per request the user makes
        authdata = auth.check_user_passphrase(authname, passphrase)
        if authdata is None:
            auditlog.log(
                {'operation': 'connect', 'user': authname, 'allowed': False})
        else:
            authenticated = True
            cfm = authdata[1]
    send_data(connection, {'authpassed': 1})
    request = tlvdata.recv(connection)
    while request is not None:
        try:
            process_request(
                connection, request, cfm, authdata, authname, skipauth)
        except exc.ForbiddenRequest:
            send_data(connection, {'errorcode': 403,
                                      'error': 'Forbidden'})
            send_data(connection, {'_requestdone': 1})
        except exc.TargetEndpointBadCredentials:
            send_data(connection, {'errorcode': 502,
                                      'error': 'Bad Credentials'})
            send_data(connection, {'_requestdone': 1})
        except exc.TargetEndpointUnreachable as tu:
            send_data(connection, {'errorcode': 504,
                                      'error': 'Unreachable Target - ' + str(
                                          tu)})
            send_data(connection, {'_requestdone': 1})
        except exc.NotImplementedException:
            send_data(connection, {'errorcode': 501,
                                      'error': 'Not Implemented'})
            send_data(connection, {'_requestdone': 1})
        except exc.NotFoundException as nfe:
            send_data(connection, {'errorcode': 404,
                                      'error': str(nfe)})
            send_data(connection, {'_requestdone': 1})
        except exc.InvalidArgumentException as iae:
            send_data(connection, {'errorcode': 400,
                                      'error': 'Bad Request - ' + str(iae)})
            send_data(connection, {'_requestdone': 1})
        except exc.LockedCredentials as lockedcred:
            send_data(connection, {'errorcode': 500,
                                      'error': 'Locked Credential Store'})
            send_data(connection, {'_requestdone': 1})
        except SystemExit:
            sys.exit(0)
        except:
            tracelog.log(traceback.format_exc(), ltype=log.DataTypes.event,
                         event=log.Events.stacktrace)
            send_data(connection, {'errorcode': 500,
                                      'error': 'Unexpected error'})
            send_data(connection, {'_requestdone': 1})
        request = tlvdata.recv(connection)


def send_response(responses, connection):
    if responses is None:
        return
    for rsp in responses:
        send_data(connection, rsp.raw())
    send_data(connection, {'_requestdone': 1})


def process_request(connection, request, cfm, authdata, authname, skipauth):
    if not isinstance(request, dict):
        raise ValueError
    operation = request['operation']
    path = request['path']
    params = request.get('parameters', None)
    hdlr = None
    if not skipauth:
        authdata = auth.authorize(authdata[2], path, authdata[3], operation)
        auditmsg = {
            'operation': operation,
            'user': authdata[2],
            'target': path,
        }
        if authdata[3] is not None:
            auditmsg['tenant'] = authdata[3]
        if authdata is None:
            auditmsg['allowed'] = False
            auditlog.log(auditmsg)
            raise exc.ForbiddenRequest()
        auditmsg['allowed'] = True
        auditlog.log(auditmsg)
    try:
        if operation == 'start':
            elems = path.split('/')
            if elems[3] != "console":
                raise exc.InvalidArgumentException()
            node = elems[2]
            ccons = ClientConsole(connection)
            skipreplay = False
            if params and 'skipreplay' in params and params['skipreplay']:
                skipreplay = True
            consession = consoleserver.ConsoleSession(
                node=node, configmanager=cfm, username=authname,
                datacallback=ccons.sendall, skipreplay=skipreplay)
            if consession is None:
                raise Exception("TODO")
            send_data(connection, {'started': 1})
            ccons.startsending()
            bufferage = consession.get_buffer_age()
            if bufferage is not False:
                send_data(connection, {'bufferage': bufferage})
            while consession is not None:
                data = tlvdata.recv(connection)
                if type(data) == dict:
                    if data['operation'] == 'stop':
                        consession.destroy()
                        return
                    elif data['operation'] == 'break':
                        consession.send_break()
                        continue
                    elif data['operation'] == 'reopen':
                        consession.reopen()
                        continue
                    else:
                        raise Exception("TODO")
                if not data:
                    consession.destroy()
                    return
                consession.write(data)
        elif operation == 'shutdown':
            configmanager.ConfigManager.shutdown()
        else:
            hdlr = pluginapi.handle_path(path, operation, cfm, params)
    except exc.NotFoundException as e:
        send_data(connection, {"errorcode": 404,
                                  "error": "Target not found - " + str(e)})
        send_data(connection, {"_requestdone": 1})
    except exc.InvalidArgumentException as e:
        send_data(connection, {"errorcode": 400,
                                  "error": "Bad Request - " + str(e)})
        send_data(connection, {"_requestdone": 1})
    send_response(hdlr, connection)
    return


def _tlshandler(bind_host, bind_port):
    plainsocket = socket.socket(socket.AF_INET6)
    plainsocket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
    plainsocket.setsockopt(socket.IPPROTO_TCP, socket.TCP_NODELAY, 1)
    plainsocket.bind((bind_host, bind_port, 0, 0))
    plainsocket.listen(5)
    while (1):  # TODO: exithook
        cnn, addr = plainsocket.accept()
        eventlet.spawn_n(_tlsstartup, cnn)


def _tlsstartup(cnn):
    authname = None
    cnn = ssl.wrap_socket(cnn, keyfile="/etc/confluent/privkey.pem",
                          certfile="/etc/confluent/srvcert.pem",
                          ssl_version=ssl.PROTOCOL_TLSv1,
                          server_side=True)
    sessionhdl(cnn, authname)

def removesocket():
    try:
        os.remove("/var/run/confluent/api.sock")
    except OSError:
        pass

def _unixdomainhandler():
    unixsocket = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
    try:
        os.remove("/var/run/confluent/api.sock")
    except OSError:  # if file does not exist, no big deal
        pass
    unixsocket.bind("/var/run/confluent/api.sock")
    os.chmod("/var/run/confluent/api.sock",
             stat.S_IWOTH | stat.S_IROTH | stat.S_IWGRP |
             stat.S_IRGRP | stat.S_IWUSR | stat.S_IRUSR)
    atexit.register(removesocket)
    unixsocket.listen(5)
    while True:
        cnn, addr = unixsocket.accept()
        creds = cnn.getsockopt(socket.SOL_SOCKET, SO_PEERCRED,
                               struct.calcsize('iII'))
        pid, uid, gid = struct.unpack('iII', creds)
        skipauth = False
        if uid in (os.getuid(), 0):
            #this is where we happily accept the person
            #to do whatever.  This allows the server to
            #start with no configuration whatsoever
            #and yet still be configurable by some means
            skipauth = True
            try:
                authname = pwd.getpwuid(uid).pw_name
            except:
                authname = "UNKNOWN SUPERUSER"
        else:
            try:
                authname = pwd.getpwuid(uid).pw_name
            except KeyError:
                cnn.close()
                return
        eventlet.spawn_n(sessionhdl, cnn, authname, skipauth)


class SockApi(object):
    def __init__(self, bindhost=None, bindport=None):
        self.tlsserver = None
        self.unixdomainserver = None
        self.bind_host = bindhost or '::'
        self.bind_port = bindport or 13001

    def start(self):
        global auditlog
        global tracelog
        tracelog = log.Logger('trace')
        auditlog = log.Logger('audit')
        self.tlsserver = eventlet.spawn(
            _tlshandler, self.bind_host, self.bind_port)
        self.unixdomainserver = eventlet.spawn(_unixdomainhandler)