import asyncio
import difflib
import html
import logging
import os
import re
import sys
import time
import urllib.parse

from telethon import TelegramClient, events, types, custom, utils, errors
from telethon.extensions import markdown

logging.basicConfig(level=logging.WARNING)
logging.getLogger('asyncio').setLevel(logging.ERROR)

try:
    import aiohttp
except ImportError:
    aiohttp = None
    logging.warning('aiohttp module not available; #haste command disabled')

def get_env(name, message, cast=str):
    if name in os.environ:
        return os.environ[name]
    while True:
        value = input(message)
        try:
            return cast(value)
        except ValueError as e:
            print(e, file=sys.stderr)
            time.sleep(1)


API_ID = get_env('TG_API_ID', 'Enter your API ID: ', int)
API_HASH = get_env('TG_API_HASH', 'Enter your API hash: ')
TOKEN = get_env('TG_TOKEN', 'Enter the bot token: ')
NAME = TOKEN.split(':')[0]
bot = TelegramClient(NAME, API_ID, API_HASH)


# ============================== Constants ==============================
WELCOME = {
-1001109500936:
    'Hi and welcome to the group. Before asking any questions, **please** '
    'read [the docs](https://telethon.readthedocs.io/). Make sure you are '
    'using the latest version with `pip3 install -U telethon`, since most '
    'problems have already been fixed in newer versions.',

-1001200633650:
    'Welcome to the off-topic group. Feel free to talk, ask or test anything '
    'here, politely. Check the description if you need to test more spammy '
    '"features" of your or other people\'s bots (sed commands too).'
}

READ_FULL = (
    'Please read [Accessing the Full API](https://telethon.readthedocs.io'
    '/en/latest/concepts/full-api.html)'
)

SEARCH = (
    'Remember [search is your friend]'
    '(https://lonamiwebs.github.io/Telethon/?q={}&redirect=no)'
)

DOCS = 'TL Reference for [{}](https://lonamiwebs.github.io/Telethon/?q={})'
RTD = '[Read The Docs!](https://telethon.readthedocs.io)'
RTFD = '[Read The F* Docs!](https://telethon.readthedocs.io)'
UPDATES = (
    'Check out [Working with Updates](https://telethon.readthedocs.io'
    '/en/latest/basic/updates.html) in the documentation.'
)
DOCS_CLIENT = 'https://telethon.readthedocs.io/en/latest/modules/client.html#'
DOCS_MESSAGE = (
    'https://telethon.readthedocs.io/en/latest/'
    'modules/custom.html#telethon.tl.custom.message.Message.'
)

SPAM = (
    "Telethon is free software. That means using it is a right: you are " 
    "free to use it for absolutely any purpose whatsoever. However, help "
    "and support with using it is a privilege. If you misbehave or want "
    "to do bad things, nobody is obligated to help you and you're not "
    "welcome here."
)

OFFTOPIC = {
    -1001109500936:
    'That is not related to Telethon. '
    'You may continue the conversation in @TelethonOffTopic',
    -1001200633650:
    'That seems to be related to Telethon. Try asking in @TelethonChat'
}

ASK = (
    "Hey, that's not how you ask a question! If you want helpful advice "
    "(or any response at all) [read this first](https://stackoverflow.com"
    "/help/how-to-ask) and then ask again. If you have the time, [How To "
    "Ask Questions The Smart Way](catb.org/~esr/faqs/smart-questions.html)"
    " is another wonderful resource worth reading."
)

LOGGING = '''
**Please enable logging:**
```import logging
logging.basicConfig(level=logging.WARNING)```

If you need more information, use `logging.DEBUG` instead.
'''

ALREADY_FIXED = (
    "This issue has already been fixed, but it's not yet available in PyPi. "
    "You can upgrade now with `pip3 install -U https://github.com/LonamiWebs"
    "/Telethon/archive/master.zip`."
)

GOOD_RESOURCES = (
    "Some good resources to learn Python:\n"
    "• [Official Docs](https://docs.python.org/3/tutorial/index.html).\n"
    "• [Dive Into Python 3](https://rawcdn.githack.com/diveintomark/"
    "diveintopython3/master/table-of-contents.html).\n"
    "• [Learn Python](https://www.learnpython.org/).\n"
    "• [Project Python](http://projectpython.net/).\n"
    "• [Computer Science Circles](https://cscircles.cemc.uwaterloo.ca/).\n"
    "• [MIT OpenCourse](https://ocw.mit.edu/courses/electrical-engineering-"
    "and-computer-science/6-0001-introduction-to-computer-science-and-progr"
    "amming-in-python-fall-2016/).\n"
    "• [Hitchhiker’s Guide to Python](https://docs.python-guide.org/).\n"
    "• The @PythonRes Telegram Channel.\n"
    "• Corey Schafer videos for [beginners](https://www.youtube.com/watch?v="
    "YYXdXT2l-Gg&list=PL-osiE80TeTskrapNbzXhwoFUiLCjGgY7) and in [general]"
    "(https://www.youtube.com/watch?v=YYXdXT2l-Gg&list=PL-osiE80TeTt2d9bfV"
    "yTiXJA-UTHn6WwU)."
)

LEARN_PYTHON = (
    "That issue is no longer related with Telethon. You should learn more "
    "Python before trying again. " + GOOD_RESOURCES
)

# ============================== Constants ==============================
# ==============================  Welcome  ==============================
last_welcome = {}


@bot.on(events.ChatAction)
async def handler(event):
    if event.user_joined:
        if event.chat_id in last_welcome:
            try:
                await last_welcome[event.chat_id].delete()
            except errors.MessageDeleteForbiddenError:
                # We believe this happens when trying to delete old messages
                pass

        last_welcome[event.chat_id] = await event.reply(WELCOME[event.chat_id])


# ==============================  Welcome  ==============================
# ==============================  Commands ==============================


@bot.on(events.NewMessage(pattern='#ping', forwards=False))
async def handler(event):
    s = time.time()
    message = await event.reply('Pong!')
    d = time.time() - s
    await message.edit(f'Pong! __(reply took {d:.2f}s)__')
    await asyncio.sleep(5)
    await asyncio.wait([event.delete(), message.delete()])


@bot.on(events.NewMessage(pattern='#full', forwards=False))
async def handler(event):
    """#full: Advises to read "Accessing the full API" in the docs."""
    await asyncio.wait([
        event.delete(),
        event.respond(READ_FULL, reply_to=event.reply_to_msg_id)
    ])


@bot.on(events.NewMessage(pattern='#search (.+)', forwards=False))
async def handler(event):
    """#search query: Searches for "query" in the method reference."""
    query = urllib.parse.quote(event.pattern_match.group(1))
    await asyncio.wait([
        event.delete(),
        event.respond(SEARCH.format(query), reply_to=event.reply_to_msg_id)
    ])


@bot.on(events.NewMessage(pattern='(?i)#(?:docs|ref) (.+)', forwards=False))
async def handler(event):
    """#docs or #ref query: Like #search but shows the query."""
    q1 = event.pattern_match.group(1)
    q2 = urllib.parse.quote(q1)
    await asyncio.wait([
        event.delete(),
        event.respond(DOCS.format(q1, q2), reply_to=event.reply_to_msg_id)
    ])


@bot.on(events.NewMessage(pattern='#rt(f)?d', forwards=False))
async def handler(event):
    """#rtd: Tells the user to please read the docs."""
    rtd = RTFD if event.pattern_match.group(1) else RTD
    await asyncio.wait([
        event.delete(),
        event.respond(rtd, reply_to=event.reply_to_msg_id)
    ])


@bot.on(events.NewMessage(pattern='#(updates|events?)', forwards=False))
async def handler(event):
    """#updates: Advices the user to read "Working with Updates"."""
    await asyncio.wait([
        event.delete(),
        event.respond(UPDATES, reply_to=event.reply_to_msg_id)
    ])


def get_docs_message(kind, query):
    kind = kind.lower()
    cls = {'client': TelegramClient, 'msg': custom.Message}[kind]

    attr = search_attr(cls, query.lower())
    if not attr:
        return f'No such method "{query}" :/'

    name = attr
    if kind == 'client':
        attr = attr_fullname(cls, attr)
        url = DOCS_CLIENT
    elif kind == 'msg':
        name = f'Message.{name}'
        url = DOCS_MESSAGE
    else:
        return f'No documentation for "{kind}"'

    return f'Documentation for [{name}]({url}{attr})'


@bot.on(events.NewMessage(pattern='(?i)#(client|msg) (.+)', forwards=False))
async def handler(event):
    """#client or #msg query: Looks for the given attribute in RTD."""
    await event.delete()

    await event.respond(
        get_docs_message(kind=event.pattern_match.group(1),
                         query=event.pattern_match.group(2)),
        reply_to=event.reply_to_msg_id
    )


@bot.on(events.NewMessage(pattern='(?i)#(ask|question)', forwards=False))
async def handler(event):
    """#ask or #question: Advices the user to ask a better question."""
    await asyncio.wait([
        event.delete(),
        event.respond(
            ASK, reply_to=event.reply_to_msg_id, link_preview=False)
    ])


@bot.on(events.NewMessage(pattern='(?i)#spam(mer|ming)?', forwards=False))
async def handler(event):
    """#spam, #spammer, #spamming: Informs spammers that they are not welcome here."""
    await asyncio.wait([
        event.delete(),
        event.respond(SPAM, reply_to=event.reply_to_msg_id)
    ])

@bot.on(events.NewMessage(pattern='(?i)#(ot|offtopic)', forwards=False))
async def handler(event):
    """#ot, #offtopic: Tells the user to move to @TelethonOffTopic."""
    await asyncio.wait([
        event.delete(),
        event.respond(OFFTOPIC[event.chat_id], reply_to=event.reply_to_msg_id)
    ])


@bot.on(events.NewMessage(pattern='(?i)#log(s|ging)?', forwards=False))
async def handler(event):
    """#log, #logs or #logging: Explains how to enable logging."""
    await asyncio.wait([
        event.delete(),
        event.respond(LOGGING, reply_to=event.reply_to_msg_id)
    ])


@bot.on(events.NewMessage(pattern='(?i)#master', forwards=False))
async def handler(event):
    """#master: The bug has been fixed in the `master` branch."""
    await asyncio.wait([
        event.delete(),
        event.respond(ALREADY_FIXED, reply_to=event.reply_to_msg_id)
    ])


@bot.on(events.NewMessage(pattern='(?i)#(learn|python)', forwards=False))
async def handler(event):
    """#learn or #python: Tells the user to learn some Python first."""
    await asyncio.wait([
        event.delete(),
        event.respond(
            LEARN_PYTHON, reply_to=event.reply_to_msg_id, link_preview=False)
    ])


@bot.on(events.NewMessage(pattern='(?i)#(list|help)', forwards=False))
async def handler(event):
    await event.delete()
    text = 'Available commands:\n'
    for callback, handler in bot.list_event_handlers():
        if isinstance(handler, events.NewMessage) and callback.__doc__:
            text += f'\n{callback.__doc__.strip()}'
    text += '\n\nYou can suggest new commands [here](https://docs.google.com/'\
            'spreadsheets/d/12yWwixUu_vB426_toLBAiajXxYKvR2J1DD6yZtQz9l4/edit).'

    message = await event.respond(text, link_preview=False)
    await asyncio.sleep(1 * text.count(' '))  # Sleep ~1 second per word
    await message.delete()


if aiohttp:
    @bot.on(events.NewMessage(pattern='(?i)#[hp]aste(bin)?', forwards=False))
    async def handler(event):
        """
        #haste: Replaces the message you reply to with a hastebin link.
        """
        await event.delete()
        if not event.reply_to_msg_id:
            return

        msg = await event.get_reply_message()
        if len(msg.raw_text or '') < 200:
            return

        sent = await event.respond(
            'Uploading paste…', reply_to=msg.reply_to_msg_id)

        name = html.escape(
            utils.get_display_name(await msg.get_sender()) or 'A user')

        text = msg.raw_text
        code = ''
        for _, string in msg.get_entities_text((
                types.MessageEntityCode, types.MessageEntityPre)):
            code += f'{string}\n'
            text = text.replace(string, '')

        code = code.rstrip()
        if code:
            text = re.sub(r'\s+', ' ', text)
        else:
            code = msg.raw_text
            text = ''

        async with aiohttp.ClientSession() as session:
            async with session.post('https://hastebin.com/documents',
                                    data=code.encode('utf-8')) as resp:
                if resp.status >= 300:
                    await sent.edit("Hastebin seems to be down… ( ^^')")
                    return

                haste = (await resp.json())['key']

        await asyncio.wait([
            msg.delete(),
            sent.edit(f'<a href="tg://user?id={msg.sender_id}">{name}</a> '
                      f'said: {text} hastebin.com/{haste}.py'
                      .replace('  ', ' '), parse_mode='html')
        ])


# ==============================  Commands ==============================
# ==============================   Inline  ==============================


@bot.on(events.InlineQuery)
async def handler(event):
    builder = event.builder
    result = None
    query = event.text.lower()
    if query == 'ping':
        result = builder.article('Pong!', text='This bot works inline')
    elif query == 'group':
        result = builder.article(
            'Move to the right group!',
            text='Try moving to the [right group](t.me/TelethonChat)',
            buttons=custom.Button.url('Join the group!', 't.me/TelethonChat'),
            link_preview=False
        )
    elif query in ('python', 'learn'):
        result = builder.article(
            'Resources to Learn Python',
            text=GOOD_RESOURCES,
            link_preview=False
        )
    else:
        m = re.match('(client|msg).(.+)', query)
        if m:
            text = get_docs_message(m.group(1), m.group(2))
            query = markdown.parse(text)[0]
            result = builder.article(query, text=text)
        else:
            m = re.match('ref.(.+)', query)
            if m:
                query = m.group(1)
                text = DOCS.format(query, urllib.parse.quote(query))
                result = builder.article(query, text=text)

    await event.answer([result] if result else None)


# ==============================   Inline  ==============================
# ============================== AutoReply ==============================


@bot.on(events.NewMessage(pattern='(?i)how (.+?)[\W]*$', forwards=False))
@bot.on(events.NewMessage(pattern='(.+?)[\W]*?\?+', forwards=False))
async def handler(event):
    words = event.pattern_match.group(1).split()
    rates = [
        search_attr(TelegramClient, ' '.join(words[-i:]), threshold=None)
        for i in range(1, 4)
    ]
    what = max(rates, key=lambda t: t[1])
    if what[1] < 0.75:
        return

    name = what[0]
    if len(name) < 4:
        return  # Short words trigger very commonly (such as "on")

    attr = attr_fullname(TelegramClient, name)
    await event.reply(
        f'Documentation for [{name}]({DOCS_CLIENT}{attr})',
        reply_to=event.reply_to_msg_id
    )

    # We have two @client.on, both could fire, stop that
    raise events.StopPropagation


# ============================== AutoReply ==============================
# ==============================  Helpers  ==============================


def search_attr(cls, query, threshold=0.6):
    seq = difflib.SequenceMatcher(b=query, autojunk=False)
    scores = []
    for n in dir(cls):
        if not n.startswith('_'):
            seq.set_seq1(n)
            scores.append((n, seq.ratio()))

    scores.sort(key=lambda t: t[1], reverse=True)
    if threshold is None:
        return scores[0]
    else:
        return scores[0][0] if scores[0][1] >= threshold else None


def attr_fullname(cls, n):
    m = getattr(cls, n)
    cls = sys.modules.get(m.__module__)
    for name in m.__qualname__.split('.')[:-1]:
        cls = getattr(cls, name)
    return cls.__module__ + '.' + cls.__name__ + '.' + m.__name__


# ==============================  Helpers  ==============================


bot.start(bot_token=TOKEN)
bot.run_until_disconnected()