"""
KIRA interface to receive UDP packets from a Keene Electronics IR-IP bridge.
"""
# pylint: disable=import-error
import os
import select
import socket
import sys
import threading
import time

from . import utils

from .constants import (
    DEFAULT_HOST,
    DEFAULT_PORT
)


class KiraReceiver(threading.Thread):
    """
    Open a UDP socket to monitor for incoming IR-IP packets.
    """

    def __init__(self, host=DEFAULT_HOST, port=DEFAULT_PORT):
        """Construct a KIRA interface object."""
        threading.Thread.__init__(self)
        self.stopped = threading.Event()
        self._callbacks = []
        self._socket = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
        self._socket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
        self.host = host
        self.port = port
        self._socket.bind((host, port))
        self.codeMap = {}
        self._state = 'idle'

    def registerCode(self, codeName, code, codeType=None):
        code = utils.mangleCode(code, codeType=codeType)
        if code:
            self.codeMap[code] = codeName

    def registerCallback(self, callback):
        self._callbacks.append(callback)

    def run(self):
        """Main loop of KIRA thread."""
        while not self.stopped.isSet():
            try:
                # if the current state is idle, just block and wait forever
                # if the current state is any other state, then a timeout of 200ms should
                # be reasonable in all cases.
                timeout = (self._state != 'idle') and 0.2 or None
                rdlist, _, _ = select.select([self._socket.fileno()], [], [], timeout)
                if not rdlist:
                    if self._state != 'idle':
                        self._state = 'idle'
                    continue
                data = self._socket.recv(1024)
                if not data:
                    # check if the socket is still valid
                    try:
                        os.fstat(recv._socket.fileno())
                    except socket.error:
                        break
                    continue
                code = utils.mangleIR(data, ignore_errors=True)
                codeName = self.codeMap.get(code)
                # some manufacturers repeat their IR codes several times in rapid
                # succession. by tracking the last code, we can eliminate redundant
                # state changes
                if codeName and (self._state != codeName):
                    self._state = codeName
                    for callback in self._callbacks:
                        callback(codeName)
            except:
                time.sleep(0.1)

    def stop(self):
        self.stopped.set()
        # force receiver thread to wake from select
        sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
        sock.connect((self.host, self.port))
        msg = "stop"
        datagram = sys.version_info[0] == 2 and bytes(msg) or bytes(msg, "utf-8")
        sock.send(datagram)
        sock.close()
        self.join()
        self._socket.close()