intercom/intercom.py

from gpiozero import LED
from gpiozero import Button

import subprocess
from threading import Thread
import socket
import yaml
import time

NO_CALL = 0
INCOMING_CALL = 1
OUTGOING_CALL = 2
OP_CALL = 'CALL'.encode()
OP_HANG = 'HANG'.encode()
OP_PING = 'PING'.encode()
OP_OK = 'OK'.encode()
OP_ERROR = 'ERROR'.encode()
CHECK_STATUS_INTERVAL = 120


class CallManager:
    state = NO_CALL
    station = None
    call_process = None

    def call(self, station):
        try:
            self.call_process = subprocess.Popen(['parole', '-c', station['host'], '-d', config['audio device']])
            s = socket.socket()
            s.connect((station['host'], station['port']))
            s.send(OP_CALL)
            response = s.recv(1024)
            print('Call notice sent', 'response=', response.decode())
            s.close()
            self.state = OUTGOING_CALL
            self.station = station
            station['red'].on()
        except Exception as e:
            print('Error al realizar la llamada: ', e)
            station['green'].off()
            self.call_process.terminate()
            self.call_process.communicate()

    def incoming_call(self, station):
        self.state = INCOMING_CALL
        self.station = station
        station['red'].on()

    def hang(self):
        print('Hang! self.station', self.station)
        if self.station is not None:
            self.station['red'].off()
        if self.call_process is not None:
            self.call_process.terminate()
            self.call_process.communicate()
        self.state = NO_CALL
        self.station = None

    def notify_hang(self):
        if self.station is not None:
            s = socket.socket()
            s.connect((self.station['host'], self.station['port']))
            s.send(OP_HANG)
            response = s.recv(1024)
            print('Hang notify sent', 'response=', response.decode())
            s.close()


callManager = CallManager()


def getstationbyip(ip):
    for s in stations:
        if s['ip'] == ip:
            return s
    return None


# Escuchamos en port para peticiones de operaciones.
def listen(call_manager):
    serversocket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    serversocket.bind(('0.0.0.0', port))
    print('Listening address', socket.gethostname(), 'on port', port)
    serversocket.listen(5)
    while True:
        # accept connections from outside
        (clientsocket, ip_address) = serversocket.accept()
        data = clientsocket.recv(1024)
        print('Connection from', ip_address, 'host=', clientsocket.getpeername(), 'data=', data.decode())
        station = getstationbyip(ip_address[0])

        if data == OP_HANG:
            call_manager.hang()
            clientsocket.send(OP_OK)
        elif data == OP_CALL:
            if callManager.state == OUTGOING_CALL or callManager.state == INCOMING_CALL:
                callManager.hang()
            call_manager.incoming_call(station)
            clientsocket.send(OP_OK)
        elif data == OP_PING:
            station['green'].on()
            clientsocket.send(OP_OK)
        else:
            clientsocket.send(OP_ERROR)
        clientsocket.close()


# Comprueba que el otro intercom esta activo.
def check_status(station):
    while True:
        s = socket.socket()
        try:
            s.connect((station['host'], station['port']))
            s.send(OP_PING)
            if s.recv(1024) == OP_OK:
                station['green'].on()
            else:
                station['red'].off()
                station['green'].off()
        except socket.error:
            station['red'].off()
            station['green'].off()
            print('Check status failed! host=', station['host'])
        finally:
            s.close()
        time.sleep(CHECK_STATUS_INTERVAL)


config = yaml.safe_load(open("intercom.yml"))
port = config['port']
stations = config['stations']

# Start thread to wait for incoming hang petitions.
thread_listen = Thread(target=listen, args=(callManager,))
thread_listen.daemon = True
thread_listen.start()

# Power off leds and start threads to check other intercoms status.
for _station in stations:
    _station['ip'] = socket.gethostbyname(_station['host'])

    _station['red'] = LED(_station['red led'])
    _station['red'].off()

    _station['green'] = LED(_station['green led'])
    _station['green'].off()

    _station['btn'] = Button(_station['button'])
    _station['old button state'] = _station['btn'].is_pressed
    _station['button state changed time'] = time.clock_gettime(time.CLOCK_MONOTONIC)
    _station['button pressed'] = False

    thread_check = Thread(target=check_status, args=(_station,))
    thread_check.daemon = True
    thread_check.start()

# Listen for swith changes.
try:
    while True:
        for _station in stations:
            # new_input_state = GPIO.input(_station['button'])
            new_input_state = _station['btn'].is_pressed
            # Al pulsar el interruptor cambia el estado.
            elapsed_time = time.clock_gettime(time.CLOCK_MONOTONIC) - _station['button state changed time']
            if new_input_state != _station['old button state'] and elapsed_time > 0.2:
                if not _station['toogle button']:
                    _station['button pressed'] = not _station['button pressed']
                    if _station['button pressed']:
                        _station['old button state'] = new_input_state
                        _station['button state changed time'] = time.clock_gettime(time.CLOCK_MONOTONIC)
                        continue
                print('Interruptor pulsado callManager.state=', callManager.state, 'elapsed_time', elapsed_time)
                # Si no hay llamada en curso la hacemos.
                if callManager.state == NO_CALL:
                    callManager.call(_station)
                elif callManager.state == OUTGOING_CALL:
                    callManager.notify_hang()
                    callManager.hang()
                elif callManager.state == INCOMING_CALL:
                    callManager.notify_hang()
                    callManager.hang()

                _station['old button state'] = new_input_state
                _station['button state changed time'] = time.clock_gettime(time.CLOCK_MONOTONIC)
        time.sleep(0.02)
finally:
    for _station in stations:
        _station['red'].close()
        _station['green'].close()
        _station['btn'].close()