AmITaskListBot.py

'''
Created on Mar 24, 2017
Copyright (c) 2016-2017 Teodoro Montanaro

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License
@author: tmontanaro
'''

from sys import argv
from telegram.ext import Updater, CommandHandler, MessageHandler, Filters

def new_task(bot, update, args):
    '''
    Add a new element to the given list
    '''

    # args is a list: when you insert words separated by a space, it considers the space as a separator and creates a list of all the inserted words
    # to re-create the string, you can simply join the words inserting a space among them
    taskToAdd = ' '.join(args)

    if taskToAdd and taskToAdd.strip() and (not taskToAdd.isspace()):
        # actually add the item to the list
        tasks_list.append(taskToAdd)
        message = "The new task was successfully added to the list!"

    else:
        message = "You did not specify any task!"
    #send the generated message to the user
    bot.sendMessage(chat_id=update.message.chat_id, text=message)
    saveListToFile()


def remove_task(bot, update, args):
    '''
    Remove an element from the given list
    '''

    # args is a list: when you insert words separated by a space, it considers the space as a separator and creates a list of all the inserted words
    # to re-create the string, you can simply join the words inserting a space among them

    taskToRemove = ' '.join(args)

    message = ''
    if taskToRemove and taskToRemove.strip() and (not taskToRemove.isspace()):
        # check if the task is actually present in the list
        if (taskToRemove in tasks_list):
            tasks_list.remove(taskToRemove)
            message="The task was successfully deleted!"
        else:
            message ="The task you specified is not in the list!"
    else:
        message = "You did not specify any task!"
    #send the generated message to the user
    bot.sendMessage(chat_id=update.message.chat_id, text=message)
    #save the list into the file
    saveListToFile()


def remove_multiple_tasks(bot, update, args):
    '''
    Remove all the elements that contain a provided string
    '''

    # create a list to store tasks we will remove at the end
    remove_list = []
    removed_elements = []
    # args is a list: when you insert words separated by a space, it considers the space as a separator and creates a list of all the inserted words
    # to re-create the string, you can simply join the words inserting a space among them
    substring = ' '.join(args)
    message = ''

    if substring and substring.strip() and (not substring.isspace()):
        # substring is not None AND substring is not empty or blank AND substring is not only made by spaces

        #mark tasks that contains the specified substring
        for single_task in tasks_list:
            #if the substring is contained in the task we save it in the remove_list
            if (substring in single_task):
                remove_list.append(single_task)
        if (len(remove_list)>0):
            for task_to_remove in remove_list:
                if (task_to_remove in tasks_list):
                    tasks_list.remove(task_to_remove)
                    removed_elements.append(task_to_remove)
            message = "The elements "+ ' , '.join(removed_elements)+" were successfully removed!"
        else:
            message = "I did not find any task to delete!"
    else:
        message = "You did not specify any string!"
    #send the generated message to the user
    bot.sendMessage(chat_id=update.message.chat_id, text=message)
    #save the list into the file
    saveListToFile()

def print_sorted_list(bot, update):
    '''
    Print the elements of the list, sorted in alphabetic order
    '''

    message = ''
    # check if the list is empty
    if (len(tasks_list) == 0):
        message="Nothing to do, here!"
    else:
        # we don't want to modify the real list of elements: we want only to print it after sorting
        # there are 2 possibilities:
        # a) using the sort method
        #  temp_tasks_list = tasks_list[:]
        #  temp_tasks_list.sort()
        #  message = temp_tasks_list
        # b) using the sorted method (the sorted method returns a new list)
        message = sorted(tasks_list)
    bot.sendMessage(chat_id=update.message.chat_id, text=message)


# define one command handler. Command handlers usually take the two arguments:
# bot and update.
def start(bot, update):
    update.message.reply_text('Hello! This is AmITaskListBot. You can use one of the following commands:')
    update.message.reply_text('/newTask <task to add>')
    update.message.reply_text('/removeTask <task to remove>')
    update.message.reply_text('/removeAllTasks <substring used to remove all the tasks that contain it>')
    update.message.reply_text('/showTasks')

def echo(bot, update):
    # get the message from the user
    receivedText = update.message.text
    textToSend = "I'm sorry,. I'm afraid I can't do that"
    bot.sendMessage(chat_id=update.message.chat_id, text=textToSend)

def saveListToFile():
    '''
    Here we save the changed list into the task_list.txt file
    '''
    filename = "task_list.txt"
    try:
        # open file in write mode
        txt = open(filename, "w")

        # write each task as a new line in the file
        for single_task in tasks_list:
            txt.write(single_task + "\n")

        # close the file
        txt.close()
    except IOError:
        print("Problems in saving todo list to file")

if __name__ == '__main__':
    # main program

    # initialize the task list
    tasks_list = []
    # get the list from the "task_list.txt" file
    filename = "task_list.txt"
    try:
        # open the file
        txt = open(filename)

        # read the file: load each row in an element of the list without "/n"
        tasks_list = txt.read().splitlines()

        # close the file
        txt.close()

    except IOError:
        # File not found! We work with an empty list
        print("File not found!")
        exit()

    updater = Updater(token='367368579:AAG5qoc_gCZdzzShjAQevHMcGn0Pm0sePVg')

    # add an handler to start the bot replying with the list of available commands
    dispatcher = updater.dispatcher
    dispatcher.add_handler(CommandHandler('start', start))

    # on non-command textual messages - echo the message on Telegram
    dispatcher.add_handler(MessageHandler(Filters.text, echo))
    
    # add an handler to insert a new task in the list
    newTask_handler = CommandHandler('newTask', new_task, pass_args=True)
    dispatcher.add_handler(newTask_handler)
    #add an handler to remove the first occurence of a specific task from the list
    removeTask_handler = CommandHandler('removeTask', remove_task, pass_args=True)
    dispatcher.add_handler(removeTask_handler)

    #add an handler to remove from the list all the existing tasks that contain a provided string
    removeAllTasks_handler = CommandHandler('removeAllTasks', remove_multiple_tasks, pass_args=True)
    dispatcher.add_handler(removeAllTasks_handler)

    #add an handler to show the list tasks
    showTasks_handler = CommandHandler('showTasks', print_sorted_list)
    dispatcher.add_handler(showTasks_handler)

    #start the bot
    updater.start_polling()