#
# Describe a connection over a socket.
#
# This class is intended to be apdapted into IEndpoint interface

import socket
from zope import interface
import errno

from interfaces import endpoint

from zope import component
from interfaces.message import Debug

@interface.implementer(endpoint.IConnection)
class SocketConnection(object):
    """ Define a connected element (serial, network…)
    """

    def __init__(self, configuration):
        self.port = int(configuration["port"])
        self.host = configuration["host"]

    def connect(self) -> None:
        """ Connect """
        self.s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        self.s.connect((self.host, self.port))
        self.s.settimeout(0.0)
        component.handle(Debug("Connected to the socket"))

    def read(self) -> str:
        """ Read from the connection and return the bytes.
            Return None if there is nothing to read (non-blocking)
            Raise an exception if disconnected """
        try:
            return self.s.recv(1024)
        except socket.error as e:
            err = e.args[0]
            if err == errno.EAGAIN or err == errno.EWOULDBLOCK:
                return None
            raise e

    def write(self, content:str) -> None:
        """ Write into the connection.
            Raise an exception if disconnected """
        self.s.sendall(content)