import os, serial, socket, subprocess, select, datetime, sys
import argparse

parser = argparse.ArgumentParser()
parser.add_argument("--serial_port", default="/dev/serial/by-id/usb-Imaginaerraum.de_DoorControl_43363220195053573A002C0-if01")
parser.add_argument("--nfc_fifo", default="/tmp/nfc_fifo")
parser.add_argument("--control_socket", default="/tmp/nfc.sock")
parser.add_argument("--valid_tokens", default="/etc/door_tokens")
parser.add_argument("--log_file", default="/tmp/nfc.log")
parser.add_argument("--state_timeout", type=float, default=10)
parser.add_argument("--repeat_time", type=float, default=5)

config = parser.parse_args()

# Log data to stdout and the log file
def log(*args):
    data = "%s %s" % (datetime.datetime.now().strftime("%Y-%m-%d %H:%M:%S"), " ".join(i for i in args))
    lgf.write(data + "\n")
    lgf.flush()
    print(data)

# Opens the socket that can control the daemon
# Commands are TBD
def open_control_socket():
    global control_socket
    global config
    global comm_channels

    if os.path.exists(config.control_socket):
        os.unlink(config.control_socket)

    control_socket = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
    control_socket.bind(config.control_socket)
    control_socket.listen(5)
    comm_channels = []

# Opens the serial port to talk to the lock actuator
# Might return a failure. In that case, it will be tried again later
def open_serial_port():
    global serial_port
    global config

    try:
        serial_port = serial.Serial(config.serial_port, timeout=2)
    except:
        serial_port = None
        pass

# Detected tokens are passed in through a FIFO
def open_nfc_fifo():
    global nfc_fifo
    global config

    nfc_fifo = open(config.nfc_fifo, "r")

# Refresh valid tokens from the configured file
def read_valid_tokens():
    global valid
    global config

    try:
        valid = [ s.strip() for s in open(config.valid_tokens, "r").readlines() ]
    except:
        valid = []
        log("No valid tokens")

# Opens the log file for writing
def open_logfile():
    global lgf
    global config

    lgf = open(config.log_file, "a+")

# Actions
IDLE, CLOSE, OPEN_THEN_CLOSE, OPEN, CLOSE_THEN_OPEN = range(5)
# Current door state
state = None
# Current target action
action = CLOSE
# Start time of the current action
start_time = datetime.datetime.now()
# How often the action was repeated
repeats = 0

# Read the state of the door from the serial port
def poll_door_state():
    global state
    global serial_port
    serial_port.reset_input_buffer()
    serial_port.write(b"R")
    data = serial_port.readline().strip().split()
    if data[0] == b'pos:':
        data = int(data[1])
        changed = False
        if data < 80 and door_state != OPEN:
            door_state = OPEN
            changed = True
        elif data > 100 and door_state != CLOSE:
            door_state = CLOSE
            changed = True
        else:
            print(data)
    return door_state

# Check the door state and send commands through a state machine
def handle_door_state():
    global action, target, serial_port, start_time, repeats
    
    state_names = {
        OPEN: "open",
        CLOSE: "close"
        }
    # Commands associated with each target state
    target_state_cmd = {
        OPEN:  b'O',
        CLOSE: b'C'
        }

    old_state = state

    # If no serial port, try to open it or return
    if not serial_port:
        try:
            open_serial_port()
        except:
            return

    # Get new state
    poll_door_state()

    # Idle + change = key?
    if target == IDLE:
        if state != old_state:
            log("Door changed unexpectedly:", state_names[state])
        return

    # Target state, next action, timeout action
    actions = {
        OPEN:  (OPEN,  IDLE, CLOSE_THEN_OPEN ),
        CLOSE: (CLOSE, IDLE, OPEN_THEN_CLOSE ),
        OPEN_THEN_CLOSE: (OPEN, CLOSE, CLOSE ),
        CLOSE_THEN_OPEN: (CLOSE, OPEN, OPEN  )
    }

    # Target state reached
    if state == actions[action][0]:
        # Select next action, reset start time and repetitions
        action = actions[action][1]
        start_time = datetime.datetime.now()
        repeats = 0
        # On idle, we're done
        if action == IDLE:
            log("Reached target position:", state_names[state])
            return

    # Execution time
    t = (datetime.datetime.now() - start_time)
    if t >= config.state_timeout:
        # Timeout -> switch to timeout action
        action = actions[action][2]
        start_time = datetime.datetime.now()
        repeats = 0
        log("Timeout. Switching to", action)
    elif t >= (1 + repeats) * config.repeat_time:
        # Repeat every couple of seconds
        repeats += 1
        serial_port.write(target_state_cmd[actions[action][0]])
        log("Repeating command:", target_state_cmd[actions[action][0]])

def open_door():
    global action
    log("Opening the door")
    action = OPEN

def close_door():
    global action
    log("Closing the door")
    action = CLOSE

def toggle_door_state():
    global state, action
    if state == CLOSE:
        open_door()
    else:
        close_door()

def handle_nfc_token():
    global valid
    
    token = nfc_fifo.readline()

    if token == "":
        open_nfc_fifo()

    token = token.strip()
    if token in valid:
        log("Valid token:", token)
        toggle_door_state()
    else:
        log("Invalid token:", token)

open_logfile()
read_valid_tokens()
open_nfc_fifo()
open_serial_port()
open_control_socket()

while True:
    readable = select.select([ nfc_fifo, control_socket ] + comm_channels, [], [], 0.5)[0]

    for c in readable:
        if c == nfc_fifo:
            handle_nfc_token()
        elif c == control_socket:
            comm_channels.append(control_socket.accept()[0])
        else:
            data = c.recv(1024)
            if len(data) == 0:
                comm_channels.remove(c)
            else:
                print("Got comms data: ", str(c.recv(1024)))
                c.sendall(b':)\n')