# -*- coding: utf-8 -*-
import random
import re
import string
import threading
import traceback
import warnings
import functools
from typing import Any, Callable, List, Dict, Optional, Union

import queue as Queue
import logging

from telebot import types

try:
    from PIL import Image
    from io import BytesIO
    pil_imported = True
except:
    pil_imported = False

MAX_MESSAGE_LENGTH = 4096

logger = logging.getLogger('TeleBot')

thread_local = threading.local()

content_type_media = [
    'text', 'audio', 'document', 'photo', 'sticker', 'video', 'video_note', 'voice', 'contact', 'dice', 'poll',
    'venue', 'location'
]

content_type_service = [
    'new_chat_members', 'left_chat_member', 'new_chat_title', 'new_chat_photo', 'delete_chat_photo', 'group_chat_created',
    'supergroup_chat_created', 'channel_chat_created', 'migrate_to_chat_id', 'migrate_from_chat_id', 'pinned_message',
    'proximity_alert_triggered', 'voice_chat_scheduled', 'voice_chat_started', 'voice_chat_ended', 
    'voice_chat_participants_invited', 'message_auto_delete_timer_changed'
]

update_types = [
    "update_id", "message", "edited_message", "channel_post", "edited_channel_post", "inline_query", 
    "chosen_inline_result", "callback_query", "shipping_query", "pre_checkout_query", "poll", "poll_answer", 
    "my_chat_member", "chat_member"
]

class WorkerThread(threading.Thread):
    count = 0

    def __init__(self, exception_callback=None, queue=None, name=None):
        if not name:
            name = "WorkerThread{0}".format(self.__class__.count + 1)
            self.__class__.count += 1
        if not queue:
            queue = Queue.Queue()

        threading.Thread.__init__(self, name=name)
        self.queue = queue
        self.daemon = True

        self.received_task_event = threading.Event()
        self.done_event = threading.Event()
        self.exception_event = threading.Event()
        self.continue_event = threading.Event()

        self.exception_callback = exception_callback
        self.exception_info = None
        self._running = True
        self.start()

    def run(self):
        while self._running:
            try:
                task, args, kwargs = self.queue.get(block=True, timeout=.5)
                self.continue_event.clear()
                self.received_task_event.clear()
                self.done_event.clear()
                self.exception_event.clear()
                logger.debug("Received task")
                self.received_task_event.set()

                task(*args, **kwargs)
                logger.debug("Task complete")
                self.done_event.set()
            except Queue.Empty:
                pass
            except Exception as e:
                logger.debug(type(e).__name__ + " occurred, args=" + str(e.args) + "\n" + traceback.format_exc())
                self.exception_info = e
                self.exception_event.set()
                if self.exception_callback:
                    self.exception_callback(self, self.exception_info)
                self.continue_event.wait()

    def put(self, task, *args, **kwargs):
        self.queue.put((task, args, kwargs))

    def raise_exceptions(self):
        if self.exception_event.is_set():
            raise self.exception_info

    def clear_exceptions(self):
        self.exception_event.clear()
        self.continue_event.set()

    def stop(self):
        self._running = False


class ThreadPool:

    def __init__(self, num_threads=2):
        self.tasks = Queue.Queue()
        self.workers = [WorkerThread(self.on_exception, self.tasks) for _ in range(num_threads)]
        self.num_threads = num_threads

        self.exception_event = threading.Event()
        self.exception_info = None

    def put(self, func, *args, **kwargs):
        self.tasks.put((func, args, kwargs))

    def on_exception(self, worker_thread, exc_info):
        self.exception_info = exc_info
        self.exception_event.set()
        worker_thread.continue_event.set()

    def raise_exceptions(self):
        if self.exception_event.is_set():
            raise self.exception_info

    def clear_exceptions(self):
        self.exception_event.clear()

    def close(self):
        for worker in self.workers:
            worker.stop()
        for worker in self.workers:
            worker.join()


class AsyncTask:
    def __init__(self, target, *args, **kwargs):
        self.target = target
        self.args = args
        self.kwargs = kwargs

        self.done = False
        self.thread = threading.Thread(target=self._run)
        self.thread.start()

    def _run(self):
        try:
            self.result = self.target(*self.args, **self.kwargs)
        except Exception as e:
            self.result = e
        self.done = True

    def wait(self):
        if not self.done:
            self.thread.join()
        if isinstance(self.result, BaseException):
            raise self.result
        else:
            return self.result


def async_dec():
    def decorator(fn):
        def wrapper(*args, **kwargs):
            return AsyncTask(fn, *args, **kwargs)

        return wrapper

    return decorator


def is_string(var):
    return isinstance(var, str)


def is_dict(var):
    return isinstance(var, dict)


def is_bytes(var):
    return isinstance(var, bytes)


def is_pil_image(var):
    return pil_imported and isinstance(var, Image.Image)


def pil_image_to_file(image, extension='JPEG', quality='web_low'):
    if pil_imported:
        photoBuffer = BytesIO()
        image.convert('RGB').save(photoBuffer, extension, quality=quality)
        photoBuffer.seek(0)
        
        return photoBuffer
    else:
        raise RuntimeError('PIL module is not imported')


def is_command(text: str) -> bool:
    """
    Checks if `text` is a command. Telegram chat commands start with the '/' character.
    :param text: Text to check.
    :return: True if `text` is a command, else False.
    """
    if text is None: return False
    return text.startswith('/')


def extract_command(text: str) -> Union[str, None]:
    """
    Extracts the command from `text` (minus the '/') if `text` is a command (see is_command).
    If `text` is not a command, this function returns None.

    Examples:
    extract_command('/help'): 'help'
    extract_command('/help@BotName'): 'help'
    extract_command('/search black eyed peas'): 'search'
    extract_command('Good day to you'): None

    :param text: String to extract the command from
    :return: the command if `text` is a command (according to is_command), else None.
    """
    if text is None: return None
    return text.split()[0].split('@')[0][1:] if is_command(text) else None


def extract_arguments(text: str) -> str:
    """
    Returns the argument after the command.
    
    Examples:
    extract_arguments("/get name"): 'name'
    extract_arguments("/get"): ''
    extract_arguments("/get@botName name"): 'name'
    
    :param text: String to extract the arguments from a command
    :return: the arguments if `text` is a command (according to is_command), else None.
    """
    regexp = re.compile(r"/\w*(@\w*)*\s*([\s\S]*)", re.IGNORECASE)
    result = regexp.match(text)
    return result.group(2) if is_command(text) else None


def split_string(text: str, chars_per_string: int) -> List[str]:
    """
    Splits one string into multiple strings, with a maximum amount of `chars_per_string` characters per string.
    This is very useful for splitting one giant message into multiples.

    :param text: The text to split
    :param chars_per_string: The number of characters per line the text is split into.
    :return: The splitted text as a list of strings.
    """
    return [text[i:i + chars_per_string] for i in range(0, len(text), chars_per_string)]


def smart_split(text: str, chars_per_string: int=MAX_MESSAGE_LENGTH) -> List[str]:
    """
    Splits one string into multiple strings, with a maximum amount of `chars_per_string` characters per string.
    This is very useful for splitting one giant message into multiples.
    If `chars_per_string` > 4096: `chars_per_string` = 4096.
    Splits by '\n', '. ' or ' ' in exactly this priority.

    :param text: The text to split
    :param chars_per_string: The number of maximum characters per part the text is split to.
    :return: The splitted text as a list of strings.
    """

    def _text_before_last(substr: str) -> str:
        return substr.join(part.split(substr)[:-1]) + substr

    if chars_per_string > MAX_MESSAGE_LENGTH: chars_per_string = MAX_MESSAGE_LENGTH

    parts = []
    while True:
        if len(text) < chars_per_string:
            parts.append(text)
            return parts

        part = text[:chars_per_string]

        if "\n" in part: part = _text_before_last("\n")
        elif ". " in part: part = _text_before_last(". ")
        elif " " in part: part = _text_before_last(" ")

        parts.append(part)
        text = text[len(part):]


def escape(text: str) -> str:
    """
    Replaces the following chars in `text` ('&' with '&amp;', '<' with '&lt;' and '>' with '&gt;').

    :param text: the text to escape
    :return: the escaped text
    """
    chars = {"&": "&amp;", "<": "&lt;", ">": "&gt"}
    for old, new in chars.items(): text = text.replace(old, new)
    return text


def user_link(user: types.User, include_id: bool=False) -> str:
    """
    Returns an HTML user link. This is useful for reports.
    Attention: Don't forget to set parse_mode to 'HTML'!

    Example:
    bot.send_message(your_user_id, user_link(message.from_user) + ' started the bot!', parse_mode='HTML')

    :param user: the user (not the user_id)
    :param include_id: include the user_id
    :return: HTML user link
    """
    name = escape(user.first_name)
    return (f"<a href='tg://user?id={user.id}'>{name}</a>" 
        + (f" (<pre>{user.id}</pre>)" if include_id else ""))


def quick_markup(values: Dict[str, Dict[str, Any]], row_width: int=2) -> types.InlineKeyboardMarkup:
    """
    Returns a reply markup from a dict in this format: {'text': kwargs}
    This is useful to avoid always typing 'btn1 = InlineKeyboardButton(...)' 'btn2 = InlineKeyboardButton(...)' 
    
    Example:
    quick_markup({
        'Twitter': {'url': 'https://twitter.com'},
        'Facebook': {'url': 'https://facebook.com'},
        'Back': {'callback_data': 'whatever'}
    }, row_width=2): 
        returns an InlineKeyboardMarkup with two buttons in a row, one leading to Twitter, the other to facebook
        and a back button below

    kwargs can be: 
    {
        'url': None, 
        'callback_data': None, 
        'switch_inline_query': None,
        'switch_inline_query_current_chat': None,
        'callback_game': None,
        'pay': None,
        'login_url': None
    }
    
    :param values: a dict containing all buttons to create in this format: {text: kwargs} {str:}
    :param row_width: int row width
    :return: InlineKeyboardMarkup
    """
    markup = types.InlineKeyboardMarkup(row_width=row_width)
    buttons = [
        types.InlineKeyboardButton(text=text, **kwargs)
        for text, kwargs in values.items()
    ]
    markup.add(*buttons)
    return markup


# CREDITS TO http://stackoverflow.com/questions/12317940#answer-12320352
def or_set(self):
    self._set()
    self.changed()


def or_clear(self):
    self._clear()
    self.changed()


def orify(e, changed_callback):
    if not hasattr(e, "_set"):
        e._set = e.set
    if not hasattr(e, "_clear"):
        e._clear = e.clear
    e.changed = changed_callback
    e.set = lambda: or_set(e)
    e.clear = lambda: or_clear(e)


def OrEvent(*events):
    or_event = threading.Event()

    def changed():
        bools = [ev.is_set() for ev in events]
        if any(bools):
            or_event.set()
        else:
            or_event.clear()

    def busy_wait():
        while not or_event.is_set():
            or_event._wait(3)

    for e in events:
        orify(e, changed)
    or_event._wait = or_event.wait
    or_event.wait = busy_wait
    changed()
    return or_event


def per_thread(key, construct_value, reset=False):
    if reset or not hasattr(thread_local, key):
        value = construct_value()
        setattr(thread_local, key, value)

    return getattr(thread_local, key)


def chunks(lst, n):
    """Yield successive n-sized chunks from lst."""
    # https://stackoverflow.com/a/312464/9935473
    for i in range(0, len(lst), n):
        yield lst[i:i + n]


def generate_random_token():
    return ''.join(random.sample(string.ascii_letters, 16))


def deprecated(warn: bool=False, alternative: Optional[Callable]=None):
    """
    Use this decorator to mark functions as deprecated.
    When the function is used, an info (or warning if `warn` is True) is logged.
    :param warn: If True a warning is logged else an info
    :param alternative: The new function to use instead
    """
    def decorator(function):
        def wrapper(*args, **kwargs):
            if not warn:
                logger.info(f"`{function.__name__}` is deprecated." 
                    + (f" Use `{alternative.__name__}` instead" if alternative else ""))
            else:
                logger.warn(f"`{function.__name__}` is deprecated." 
                    + (f" Use `{alternative.__name__}` instead" if alternative else ""))
            return function(*args, **kwargs)
        return wrapper
    return decorator