#!/usr/bin/env python3

"""

Use this to print JSON directly to console from whatever camera.

"""

import json
import socketserver
from functools import wraps, partial
from argparse import ArgumentParser

ap = ArgumentParser()
ap.add_argument( "--port", default=55555, type=int )
ap.add_argument( "--host", default="localhost" )



class TCPHandler( socketserver.BaseRequestHandler ):
    """
    """

    def __init__( self, callback, *a, **kw ):
        self.callback = callback
        super().__init__( *a, **kw )

    def handle(self):

        while True:
            self.data = self.request.recv(4096)
            if not self.data:
                break
            self.callback( self.data )


class ThreadedTCPServer( socketserver.ThreadingMixIn, socketserver.TCPServer ):
    pass



class StreamHandler():

    def __init__(self, name='', on_except=None):
        self.name = name
        self.callbacks = list()
        if on_except:
            self.on_except = on_except
        else:
            def on_except(e):
                print( type(e).__name__, e )
            self.on_except = on_except


    def update(self, val):
        try:
            v = val.decode()
            for cb in self.callbacks:
                cb( v )
        except Exception as e:
            self.on_except(e)


    def new_callback( self, func ):

        charbuffer = ""
        json_strings = []

        @wraps( func )
        def callback( charstring ):
            nonlocal charbuffer
            nonlocal json_strings
            for c in charstring:
                charbuffer += c
                if charbuffer[-4:] in "\r\n\r\n\r":
                    json_strings.append(charbuffer[:-4])
                    charbuffer = ""
            for s in json_strings:
                obj = json.loads(s)
                func( obj )
            json_strings = []

        self.callbacks.append( callback )


if __name__ == '__main__':

    args = vars(ap.parse_args())
    port = args["port"]
    host = args["host"]

    x = StreamHandler()

    @x.new_callback
    def vrm_printer( json_obj ):
        if "decodes" in json_obj:
            json_obj=json_obj["decodes"][0]
        vrm = json_obj.get("vrm") or json_obj.get("vrm2")
        meta_type = json_obj.get( "meta_type" ) or ""
        if vrm:
            print( vrm + " " + meta_type )

    server = ThreadedTCPServer((host, port), partial( TCPHandler, x.update ) )
    server.serve_forever()

    print("Cam stream closed.")