import random
import re

import telethon
import yaml
import pgbotlib.api
import pgbotlib.dbstuff
import pgbotlib.misc


def get_token(token_name: str, token_regex: list) -> tuple:
    regex = []
    for i in token_regex:
        regex.append(re.compile(i))
    return token_name, regex


def get_tokens(path: str) -> list:
    with open(path, 'r', encoding='utf-8') as data:
        tokens = yaml.safe_load(data.read())
    return [get_token(i, tokens[i]) for i in tokens]


class Responder:
    def __init__(self, config: dict,
                 client: telethon.TelegramClient,
                 db_connection: pgbotlib.dbstuff.DBConn,
                 namegen: pgbotlib.misc.NameGenerator) -> None:
        # apiregex matches "{apiname}optional data"
        # message itself is also passed to the api call method
        self.enabled = True
        self.apiregex = re.compile(r'^\{(\w+)\}(.+)?$')
        self.namegen = pgbotlib.misc.NameGenerator(config, db_connection)
        self.tokens = get_tokens(config.get('response_tokens', 'tokens.yml'))
        self.chats = config['chats']
        self.api = pgbotlib.api.ApiWrapper(self.tokens, db_connection)
        self.db_connection = db_connection
        self.client = client

    def tokenize(self, message: str) -> frozenset:
        tokens = set()
        for token, regexi in self.tokens:
            for regex in regexi:
                if regex.search(message):
                    tokens.add(token)
                    break
        return frozenset(tokens)

    def __get_keys(self) -> dict:
        result = {}
        query = 'SELECT DISTINCT tokens FROM responses'
        for i in self.db_connection.query_raw(query, tuple()):
            result[frozenset(i[0].split(','))] = i[0]
        return result

    def __response_choice(self, key: str) -> str:
        return self.db_connection.query_random(
                "SELECT response FROM responses WHERE tokens = %s", (key,))

    def enable(self) -> None:
        self.enabled = True

    def disable(self) -> None:
        self.enabled = False

    def is_enabled(self) -> bool:
        return self.enabled

    def get_response(self, tokens: frozenset) -> str:
        counter = 0
        keys = self.__get_keys()
        for items, string in keys.items():
            if items <= tokens:
                # check for priority tokens
                for token in items:
                    if token.startswith('!'):
                        return self.__response_choice(string)
                match_length = len(items & tokens)
                if match_length > counter:
                    counter = match_length
                    key = string
        if not counter:
            return None
        return self.__response_choice(key)

    def api_match(self, response: str, message: str) -> str:
        match = self.apiregex.search(response)
        if not match:
            return response
        api_spec = match.groups()
        return self.api.call(*api_spec, message)

    async def user_tmpl(self, response: str,
                        event: telethon.events.common.EventBuilder) -> str:
        marker = '<username>'
        if marker not in response:
            return response
        sender = await event.get_sender()
        username = self.namegen.get_name(sender)
        return response.replace(marker, username)

    async def rndm_tmpl(self, response: str, chat_id: str) -> str:
        marker = '<randomname>'
        if marker not in response:
            return response
        users = await self.client.get_participants(entity=chat_id)
        victim = random.choice(users)
        username = self.namegen.get_name(victim)
        return response.replace('<randomname>', username)

    async def respond(self,
                      event: telethon.events.common.EventBuilder) -> None:
        if not self.enabled:
            return None
        chat_id = telethon.utils.get_peer_id(event.message.peer_id)
        if chat_id not in self.chats:
            return None
        message = event.message.text.lower()
        tokens = self.tokenize(message)
        response = self.get_response(tokens)
        if not response:
            return None
        response = self.api_match(response, message)
        response = await self.user_tmpl(response, event)
        response = await self.rndm_tmpl(response, chat_id)
        await self.client.send_message(chat_id, response)