# -*- coding: utf-8 -*-
import logging
import os
import re
import time

from collections import namedtuple
from os import listdir
from threading import Thread, Lock

import openerp.addons.hw_proxy.controllers.main as hw_proxy
from openerp import http

_logger = logging.getLogger(__name__)

DRIVER_NAME = 'scale'

try:
    import serial
except ImportError:
    _logger.error('Odoo module hw_scale depends on the pyserial python module')
    serial = None


def _toledo8217StatusParse(status):
    """ Parse a scale's status, returning a `(weight, weight_info)` pair. """
    weight, weight_info = None, None
    stat = ord(status[status.index('?') + 1])
    if stat == 0:
        weight_info = 'ok'
    else:
        weight_info = []
        if stat & 1 :
            weight_info.append('moving')
        if stat & 1 << 1:
            weight_info.append('over_capacity')
        if stat & 1 << 2:
            weight_info.append('negative')
            weight = 0.0
        if stat & 1 << 3:
            weight_info.append('outside_zero_capture_range')
        if stat & 1 << 4:
            weight_info.append('center_of_zero')
        if stat & 1 << 5:
            weight_info.append('net_weight')
    return weight, weight_info

ScaleProtocol = namedtuple(
    'ScaleProtocol',
    "name baudrate bytesize stopbits parity timeout writeTimeout weightRegexp statusRegexp "
    "statusParse commandTerminator commandDelay weightDelay newWeightDelay "
    "weightCommand zeroCommand tareCommand clearCommand emptyAnswerValid autoResetWeight")

# 8217 Mettler-Toledo (Weight-only) Protocol, as described in the scale's Service Manual.
#    e.g. here: https://www.manualslib.com/manual/861274/Mettler-Toledo-Viva.html?page=51#manual
# Our recommended scale, the Mettler-Toledo "Ariva-S", supports this protocol on
# both the USB and RS232 ports, it can be configured in the setup menu as protocol option 3.
# We use the default serial protocol settings, the scale's settings can be configured in the
# scale's menu anyway.
Toledo8217Protocol = ScaleProtocol(
    name='Toledo 8217',
    baudrate=9600,
    bytesize=serial.SEVENBITS,
    stopbits=serial.STOPBITS_ONE,
    parity=serial.PARITY_EVEN,
    timeout=1,
    writeTimeout=1,
    weightRegexp="\x02\\s*([0-9.]+)N?\\r",
    statusRegexp="\x02\\s*(\\?.)\\r",
    statusParse=_toledo8217StatusParse,
    commandDelay=0.2,
    weightDelay=0.5,
    newWeightDelay=0.2,
    commandTerminator='',
    weightCommand='W',
    zeroCommand='Z',
    tareCommand='T',
    clearCommand='C',
    emptyAnswerValid=False,
    autoResetWeight=False,
)

# The ADAM scales have their own RS232 protocol, usually documented in the scale's manual
#   e.g at https://www.adamequipment.com/media/docs/Print%20Publications/Manuals/PDF/AZEXTRA/AZEXTRA-UM.pdf
#          https://www.manualslib.com/manual/879782/Adam-Equipment-Cbd-4.html?page=32#manual
# Only the baudrate and label format seem to be configurable in the AZExtra series.
ADAMEquipmentProtocol = ScaleProtocol(
    name='Adam Equipment',
    baudrate=4800,
    bytesize=serial.EIGHTBITS,
    stopbits=serial.STOPBITS_ONE,
    parity=serial.PARITY_NONE,
    timeout=0.2,
    writeTimeout=0.2,
    weightRegexp=r"\s*([0-9.]+)kg", # LABEL format 3 + KG in the scale settings, but Label 1/2 should work
    statusRegexp=None,
    statusParse=None,
    commandTerminator="\r\n",
    commandDelay=0.2,
    weightDelay=0.5,
    newWeightDelay=5,  # AZExtra beeps every time you ask for a weight that was previously returned!
                       # Adding an extra delay gives the operator a chance to remove the products
                       # before the scale starts beeping. Could not find a way to disable the beeps.
    weightCommand='P',
    zeroCommand='Z',
    tareCommand='T',
    clearCommand=None, # No clear command -> Tare again
    emptyAnswerValid=True, # AZExtra does not answer unless a new non-zero weight has been detected
    autoResetWeight=True,  # AZExtra will not return 0 after removing products
)


SCALE_PROTOCOLS = (
    Toledo8217Protocol,
    ADAMEquipmentProtocol, # must be listed last, as it supports no probing!
)

class Scale(Thread):
    def __init__(self):
        Thread.__init__(self)
        self.lock = Lock()
        self.scalelock = Lock()
        self.status = {'status':'connecting', 'messages':[]}
        self.input_dir = '/dev/serial/by-path/'
        self.weight = 0
        self.weight_info = 'ok'
        self.device = None
        self.path_to_scale = ''
        self.protocol = None

    def lockedstart(self):
        with self.lock:
            if not self.isAlive():
                self.daemon = True
                self.start()

    def set_status(self, status, message=None):
        if status == self.status['status']:
            if message is not None and message != self.status['messages'][-1]:
                self.status['messages'].append(message)

                if status == 'error' and message:
                    _logger.error('Scale Error: '+ message)
                elif status == 'disconnected' and message:
                    _logger.warning('Disconnected Scale: '+ message)
        else:
            self.status['status'] = status
            if message:
                self.status['messages'] = [message]
            else:
                self.status['messages'] = []

            if status == 'error' and message:
                _logger.error('Scale Error: '+ message)
            elif status == 'disconnected' and message:
                _logger.warning('Disconnected Scale: '+message)

    def _get_raw_response(self, connection):
        answer = []
        while True:
            char = connection.read(1) # may return `bytes` or `str`
            if not char:
                break
            else:
                answer.append(char)
        return ''.join(answer)

    def _parse_weight_answer(self, protocol, answer):
        """ Parse a scale's answer to a weighing request, returning
            a `(weight, weight_info, status)` pair.
        """
        weight, weight_info, status = None, None, None
        try:
            _logger.debug("Parsing weight [%r]", answer)
            if not answer and protocol.emptyAnswerValid:
                # Some scales do not return the same value again, but we
                # should not clear the weight data, POS may still be reading it
                return weight, weight_info, status

            if protocol.statusRegexp and re.search(protocol.statusRegexp, answer):
                # parse status to set weight_info - we'll try weighing again later
                weight, weight_info = protocol.statusParse(answer)
            else:
                match = re.search(protocol.weightRegexp, answer)
                if match:
                    weight_text = match.group(1)
                    try:
                        weight = float(weight_text)
                        _logger.info('Weight: %s', weight)
                    except ValueError:
                        _logger.exception("Cannot parse weight [%r]", weight_text)
                        status = 'Invalid weight, please power-cycle the scale'
                else:
                    _logger.error("Cannot parse scale answer [%r]", answer)
                    status = 'Invalid scale answer, please power-cycle the scale'
        except Exception as e:
            _logger.exception("Cannot parse scale answer [%r]", answer)
            status = ("Could not weigh on scale %s with protocol %s: %s" %
                      (self.path_to_scale, protocol.name, e))
        return weight, weight_info, status

    def get_device(self):
        if self.device:
            return self.device

        with hw_proxy.rs232_lock:
            try:
                if not os.path.exists(self.input_dir):
                    self.set_status('disconnected', 'No RS-232 device found')
                    return None

                devices = [device for device in listdir(self.input_dir)]

                for device in devices:
                    driver = hw_proxy.rs232_devices.get(device)
                    if driver and driver != DRIVER_NAME:
                        # belongs to another driver
                        _logger.info('Ignoring %s, belongs to %s', device, driver)
                        continue
                    path = self.input_dir + device
                    for protocol in SCALE_PROTOCOLS:
                        _logger.info('Probing %s with protocol %s', path, protocol)
                        connection = serial.Serial(path,
                                                   baudrate=protocol.baudrate,
                                                   bytesize=protocol.bytesize,
                                                   stopbits=protocol.stopbits,
                                                   parity=protocol.parity,
                                                   timeout=1,      # longer timeouts for probing
                                                   writeTimeout=1) # longer timeouts for probing
                        connection.write(protocol.weightCommand + protocol.commandTerminator)
                        time.sleep(protocol.commandDelay)
                        answer = self._get_raw_response(connection)
                        weight, weight_info, status = self._parse_weight_answer(protocol, answer)
                        if status:
                            _logger.info('Probing %s: no valid answer to protocol %s', path, protocol.name)
                        else:
                            _logger.info('Probing %s: answer looks ok for protocol %s', path, protocol.name)
                            self.path_to_scale = path
                            self.protocol = protocol
                            self.set_status(
                                'connected',
                                'Connected to %s with %s protocol' % (device, protocol.name)
                            )
                            connection.timeout = protocol.timeout
                            connection.writeTimeout = protocol.writeTimeout
                            hw_proxy.rs232_devices[path] = DRIVER_NAME
                            return connection

                self.set_status('disconnected', 'No supported RS-232 scale found')
            except Exception as e:
                _logger.exception('Failed probing for scales')
                self.set_status('error', 'Failed probing for scales: %s' % e)
            return None

    def get_weight(self):
        self.lockedstart()
        return self.weight

    def get_weight_info(self):
        self.lockedstart()
        return self.weight_info

    def get_status(self):
        self.lockedstart()
        return self.status

    def read_weight(self):
        with self.scalelock:
            p = self.protocol
            try:
                self.device.write(p.weightCommand + p.commandTerminator)
                time.sleep(p.commandDelay)
                answer = self._get_raw_response(self.device)
                weight, weight_info, status = self._parse_weight_answer(p, answer)
                if status:
                    self.set_status('error', status)
                    self.device = None
                else:
                    if weight is not None:
                        self.weight = weight
                    if weight_info is not None:
                        self.weight_info = weight_info
            except Exception as e:
                self.set_status(
                    'error',
                    "Could not weigh on scale %s with protocol %s: %s" %
                    (self.path_to_scale, p.name, e))
                self.device = None

    def set_zero(self):
        with self.scalelock:
            if self.device:
                try:
                    self.device.write(self.protocol.zeroCommand + self.protocol.commandTerminator)
                    time.sleep(self.protocol.commandDelay)
                except Exception as e:
                    self.set_status(
                        'error',
                        "Could not zero scale %s with protocol %s: %s" %
                        (self.path_to_scale, self.protocol.name, e))
                    self.device = None

    def set_tare(self):
        with self.scalelock:
            if self.device:
                try:
                    self.device.write(self.protocol.tareCommand + self.protocol.commandTerminator)
                    time.sleep(self.protocol.commandDelay)
                except Exception as e:
                    self.set_status(
                        'error',
                        "Could not tare scale %s with protocol %s: %s" %
                        (self.path_to_scale, self.protocol.name, e))
                    self.device = None

    def clear_tare(self):
        with self.scalelock:
            if self.device:
                p = self.protocol
                try:
                    # if the protocol has no clear, we can just tare again
                    clearCommand = p.clearCommand or p.tareCommand
                    self.device.write(clearCommand + p.commandTerminator)
                    time.sleep(p.commandDelay)
                except Exception as e:
                    self.set_status(
                        'error',
                        "Could not clear tare on scale %s with protocol %s: %s" %
                        (self.path_to_scale, p.name, e))
                    self.device = None

    def run(self):
        self.device = None

        while True:
            if self.device:
                old_weight = self.weight
                self.read_weight()
                if self.weight != old_weight:
                    _logger.info('New Weight: %s, sleeping %ss', self.weight, self.protocol.newWeightDelay)
                    time.sleep(self.protocol.newWeightDelay)
                    if self.weight and self.protocol.autoResetWeight:
                        self.weight = 0
                else:
                    _logger.info('Weight: %s, sleeping %ss', self.weight, self.protocol.weightDelay)
                    time.sleep(self.protocol.weightDelay)
            else:
                with self.scalelock:
                    self.device = self.get_device()
                if not self.device:
                    # retry later to support "plug and play"
                    time.sleep(10)

scale_thread = None
if serial:
    scale_thread = Scale()
    hw_proxy.drivers[DRIVER_NAME] = scale_thread

class ScaleDriver(hw_proxy.Proxy):
    @http.route('/hw_proxy/scale_read/', type='json', auth='none', cors='*')
    def scale_read(self):
        if scale_thread:
            return {'weight': scale_thread.get_weight(),
                    'unit': 'kg',
                    'info': scale_thread.get_weight_info()}
        return None

    @http.route('/hw_proxy/scale_zero/', type='json', auth='none', cors='*')
    def scale_zero(self):
        if scale_thread:
            scale_thread.set_zero()
        return True

    @http.route('/hw_proxy/scale_tare/', type='json', auth='none', cors='*')
    def scale_tare(self):
        if scale_thread:
            scale_thread.set_tare()
        return True

    @http.route('/hw_proxy/scale_clear_tare/', type='json', auth='none', cors='*')
    def scale_clear_tare(self):
        if scale_thread:
            scale_thread.clear_tare()
        return True