#!/usr/bin/env python
# -*- coding: utf-8 -*-
# This program is dedicated to the public domain under the CC0 license.

"""
Simple Bot to send timed Telegram messages.

This Bot uses the Updater class to handle the bot and the JobQueue to send
timed messages.

First, a few handler functions are defined. Then, those functions are passed to
the Dispatcher and registered at their respective places.
Then, the bot is started and runs until we press Ctrl-C on the command line.

Usage:
Basic Alarm Bot example, sends a message after a set time.
Press Ctrl-C on the command line or send a signal to the process to stop the
bot.
"""

import logging

from telegram.ext import Updater, CommandHandler

# Enable logging
logging.basicConfig(format='%(asctime)s - %(name)s - %(levelname)s - %(message)s',
                    level=logging.INFO)

logger = logging.getLogger(__name__)


# Define a few command handlers. These usually take the two arguments update and
# context. Error handlers also receive the raised TelegramError object in error.
def start(update, context):
    update.message.reply_text('Hi! Use /set <seconds> to set a timer')


def alarm(context):
    """Send the alarm message."""
    job = context.job
    context.bot.send_message(job.context, text='Beep!')


def set_timer(update, context):
    """Add a job to the queue."""
    chat_id = update.message.chat_id
    try:
        # args[0] should contain the time for the timer in seconds
        due = int(context.args[0])
        if due < 0:
            update.message.reply_text('Sorry we can not go back to future!')
            return

        # Add job to queue and stop current one if there is a timer already
        if 'job' in context.chat_data:
            old_job = context.chat_data['job']
            old_job.schedule_removal()
        new_job = context.job_queue.run_once(alarm, due, context=chat_id)
        context.chat_data['job'] = new_job

        update.message.reply_text('Timer successfully set!')

    except (IndexError, ValueError):
        update.message.reply_text('Usage: /set <seconds>')


def unset(update, context):
    """Remove the job if the user changed their mind."""
    if 'job' not in context.chat_data:
        update.message.reply_text('You have no active timer')
        return

    job = context.chat_data['job']
    job.schedule_removal()
    del context.chat_data['job']

    update.message.reply_text('Timer successfully unset!')


def error(update, context):
    """Log Errors caused by Updates."""
    logger.warning('Update "%s" caused error "%s"', update, context.error)


def main():
    """Run bot."""
    # Create the Updater and pass it your bot's token.
    # Make sure to set use_context=True to use the new context based callbacks
    # Post version 12 this will no longer be necessary
    updater = Updater("TOKEN", use_context=True)

    # Get the dispatcher to register handlers
    dp = updater.dispatcher

    # on different commands - answer in Telegram
    dp.add_handler(CommandHandler("start", start))
    dp.add_handler(CommandHandler("help", start))
    dp.add_handler(CommandHandler("set", set_timer,
                                  pass_args=True,
                                  pass_job_queue=True,
                                  pass_chat_data=True))
    dp.add_handler(CommandHandler("unset", unset, pass_chat_data=True))

    # log all errors
    dp.add_error_handler(error)

    # Start the Bot
    updater.start_polling()

    # Block until you press Ctrl-C or the process receives SIGINT, SIGTERM or
    # SIGABRT. This should be used most of the time, since start_polling() is
    # non-blocking and will stop the bot gracefully.
    updater.idle()


if __name__ == '__main__':
    main()