#!/usr/bin/env python

import sys
import cmd
import struct
import socket
import os

#------------------------------------------------------------------------------

class CLI(cmd.Cmd):
    """Simple command-line interface for the X-Plane Remote Access plugin."""
    _types = { "i"  : 0x01,
               "f"  : 0x02,
               "d"  : 0x03,
               "fa" : 0x11,
               "ia" : 0x12,
               "ba" : 0x13 }

    @staticmethod
    def _packLength(x):
        """Pack the given integer as a variable-length value."""
        s = ""
        while True:
            y = x&0x7f
            x >>= 7
            if x>0: y |= 0x80
            s += struct.pack("B", y)
            if x==0:
                return s

    @staticmethod
    def _packString(s):
        """Pack the given string."""
        return CLI._packLength(len(s)) + s

    def __init__(self, stream):
        """Construct the CLI."""
        cmd.Cmd.__init__(self)

        self._stream = stream

        self.use_rawinput = True
        self.intro = "\nX-Plane Remote Access plugin command prompt\n"
        self.prompt = "XPLRA> "

        self.daemon = True

    def default(self, line):
        """Handle uhandled commands"""
        if line=="EOF":
            print
            return True
        else:
            return super(CLI, self).default(line)

    def do_get(self, args):
        """Handle the 'get' command"""
        words = args.split()
        if len(words)<2:
            print >> sys.stderr, "Missing parameters"
            return False

        name = words[0]

        type = words[1]
        if type not in self._types:
            print >> sys.stderr, "Invalid type"
            return False

        length = None
        offset = None
        if len(words)>3:
            length = int(words[2])
            offset = int(words[3])

        self._writeU8(0x01)
        self._writeString(name)
        self._writeU8(self._types[type])
        if length is not None:
            self._writeS32(length)
            self._writeS32(offset)
        self._flush()

        result = self._readU8()
        if result==0:
            value = None
            if type=="i":
                value = self._readS32()
            elif type=="f":
                value = self._readFloat()
            elif type=="d":
                value = self._readDouble()
            elif type=="fa":
                length = self._readS32()
                if length>0:
                    value = [self._readFloat() for i in range(0, length)]
            elif type=="ia":
                length = self._readS32()
                if length>0:
                    value = [self._readS32() for i in range(0, length)]
            elif type=="ba":
                length = self._readS32()
                if length>0:
                    bytes = [self._readU8() for i in range(0, length)]
                    value = ""
                    for b in bytes:
                        if b==0: break
                        value += chr(b)
                    #value = bytes

            print value
        else:
            print "Result code:", result

    def _writeU8(self, x):
        """Write the given value as an unsigned, 8-bit value."""
        self._stream.write(struct.pack("B", x))

    def _writeS32(self, x):
        """Write the given value as a signed, 32-bit value."""
        self._stream.write(struct.pack("i", x))

    def _writeLength(self, length):
        """Write the given value is a variable-length value into our stream."""
        self._stream.write(self._packLength(length))

    def _writeString(self, str):
        """Write the given string into the stream."""
        self._stream.write(self._packString(str))

    def _flush(self):
        """Flush our stream."""
        self._stream.flush()

    def _readU8(self):
        """Read an unsigned, 8-bit value from the stream."""
        (value,) = struct.unpack("B", self._stream.read(1))
        return value

    def _readS32(self):
        """Read a signed, 32-bit value from the stream."""
        (value,) = struct.unpack("i", self._stream.read(4))
        return value

    def _readFloat(self):
        """Read a single-precision floating point value from the stream."""
        (value,) = struct.unpack("f", self._stream.read(4))
        return value

    def _readDouble(self):
        """Read a double-precision floating point value from the stream."""
        (value,) = struct.unpack("d", self._stream.read(8))
        return value

    def _readLength(self):
        """Read a variable-length value from our stream."""
        length = 0
        while True:
            (x,) = struct.unpack("B", self._stream.read(1))
            length <<= 7
            length |= x&0x7f
            if x&0x80==0:
                return length

    @staticmethod
    def _readString(self):
        """Read a string from our stream."""
        length = self._readLength()
        return self._stream.read(length)

#------------------------------------------------------------------------------

if __name__ == "__main__":
    s = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
    s.connect("/tmp/xplra-" + os.environ["LOGNAME"])
    CLI(s.makefile()).cmdloop()