#    This file is part of the Minecraft Overviewer.
#
#    Minecraft Overviewer is free software: you can redistribute it and/or
#    modify it under the terms of the GNU General Public License as published
#    by the Free Software Foundation, either version 3 of the License, or (at
#    your option) any later version.
#
#    Minecraft Overviewer is distributed in the hope that it will be useful,
#    but WITHOUT ANY WARRANTY; without even the implied warranty of
#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General
#    Public License for more details.
#
#    You should have received a copy of the GNU General Public License along
#    with the Overviewer.  If not, see <http://www.gnu.org/licenses/>.

import socket
import struct
import select


class RConException(Exception):
    def __init__(self, request_id, reason):
        self.request_id = request_id
        self.reason = reason

    def __str__(self):
        return ("Failed RCon request with request ID %d, reason %s" %
                (self.request_id, self.reason))


class RConConnection():
    rid = 0

    def __init__(self, target, port):
        self.sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        self.sock.connect((target, port))

    def send(self, t, payload):
        self.rid = self.rid + 1
        header = struct.pack("<iii",
                             len(payload) + 4 + 4 + 2,  # rid, type and padding
                             self.rid, t)
        data = header + payload + '\x00\x00'
        self.sock.send(data)

        toread = select.select([self.sock], [], [], 30)

        if not toread:
            raise RConException(self.rid, "Request timed out.")

        try:
            res_len, res_id, res_type = \
                struct.unpack("<iii", self.sock.recv(12, socket.MSG_WAITALL))
        except Exception as e:
            raise RConException(self.rid,
                                "RCon protocol error. Are you sure you're "
                                "talking to the RCon port? Error: %s" % e)
        res_data = self.sock.recv(res_len - 4 - 4)
        res_data = res_data[:-2]

        if res_id == -1:
            if t == 3:
                raise RConException(self.rid, "Login failed.")
            else:
                raise RConException(self.rid,
                                    "Request failed due to invalid login.")
        elif res_id != self.rid:
            raise RConException(self.rid, "Received unexpected response "
                                "number: %d" % res_id)
        return res_data

    def login(self, password):
        self.send(3, password)

    def command(self, com, args):
        self.send(2, com + " " + args)

    def close(self):
        self.sock.close()