import logging

from prometheus_client import Counter, Summary
from telegram.ext import CommandHandler, Updater

from smsbot.utils import get_smsbot_version

REQUEST_TIME = Summary('telegram_request_processing_seconds', 'Time spent processing request')
COMMAND_COUNT = Counter('telegram_command_count', 'Total number of commands processed')


class TelegramSmsBot(object):

    def __init__(self, telegram_token, allow_subscribing=False, owner=None, subscribers=None):
        self.logger = logging.getLogger(self.__class__.__name__)
        self.bot_token = telegram_token
        self.subscriber_ids = subscribers or []
        self.set_owner(owner)

        self.updater = Updater(self.bot_token, use_context=True)
        self.updater.dispatcher.add_handler(CommandHandler('help', self.help_handler))
        self.updater.dispatcher.add_handler(CommandHandler('start', self.help_handler))

        if allow_subscribing:
            self.updater.dispatcher.add_handler(CommandHandler('subscribe', self.subscribe_handler))
            self.updater.dispatcher.add_handler(CommandHandler('unsubscribe', self.unsubscribe_handler))

        self.updater.dispatcher.add_error_handler(self.error_handler)

    def start(self):
        self.logger.info('Starting bot...')
        self.updater.start_polling()
        self.bot = self.updater.bot
        self.logger.info('Bot Ready')

    def stop(self):
        self.updater.stop()

    @REQUEST_TIME.time()
    def help_handler(self, update, context):
        """Send a message when the command /help is issued."""
        self.logger.info('/help command received in chat: %s', update.message.chat)

        commands = []
        for command in self.updater.dispatcher.handlers[0]:
            commands.extend(['/{0}'.format(cmd) for cmd in command.command])

        update.message.reply_markdown('Smsbot v{0}\n\n{1}'.format(get_smsbot_version(), '\n'.join(commands)))
        COMMAND_COUNT.inc()

    @REQUEST_TIME.time()
    def subscribe_handler(self, update, context):
        self.logger.info('/subscribe command received')
        if update.message.chat['id'] not in self.subscriber_ids:
            self.logger.info('{0} subscribed'.format(update.message.chat['username']))
            self.subscriber_ids.append(update.message.chat['id'])
            self.send_owner('{0} has subscribed'.format(update.message.chat['username']))
            update.message.reply_markdown('You have been subscribed to SMS notifications')
        else:
            update.message.reply_markdown('You are already subscribed to SMS notifications')
        COMMAND_COUNT.inc()

    @REQUEST_TIME.time()
    def unsubscribe_handler(self, update, context):
        self.logger.info('/unsubscribe command received')
        if update.message.chat['id'] in self.subscriber_ids:
            self.logger.info('{0} unsubscribed'.format(update.message.chat['username']))
            self.subscriber_ids.remove(update.message.chat['id'])
            self.send_owner('{0} has unsubscribed'.format(update.message.chat['username']))
            update.message.reply_markdown('You have been unsubscribed to SMS notifications')
        else:
            update.message.reply_markdown('You are not subscribed to SMS notifications')
        COMMAND_COUNT.inc()

    def error_handler(self, update, context):
        """Log Errors caused by Updates."""
        self.logger.warning('Update "%s" caused error "%s"', update, context.error)
        self.send_owner('Update "%{0}" caused error "{1}"'.format(update, context.error))

    def send_message(self, message, chat_id):
        self.bot.sendMessage(text=message, chat_id=chat_id)

    def send_owner(self, message):
        if self.owner_id:
            self.send_message(message, self.owner_id)

    def send_subscribers(self, message):
        for chat_id in self.subscriber_ids:
            self.send_message(message, chat_id)

    def set_owner(self, chat_id):
        self.owner_id = chat_id
        if self.owner_id and self.owner_id not in self.subscriber_ids:
            self.subscriber_ids.append(self.owner_id)

    def add_subscriber(self, chat_id):
        self.subscriber_ids.append(chat_id)