import logging
import os
import psycopg2
from datetime import datetime
from telethon.sync import TelegramClient
from telethon.tl.functions.messages import GetHistoryRequest

LOG_FILE = os.getenv('LOG_FILE', '/app/tg_nodes.log')

if os.path.exists(LOG_FILE) and os.path.isdir(LOG_FILE):
    raise RuntimeError(f"Path {LOG_FILE} is a directory! Expected file.")

logging.basicConfig(
    handlers=[
        logging.FileHandler(LOG_FILE),
        logging.StreamHandler()
    ]
)

class TelegramChannelMonitor:
    db_config = None

    def __init__(self, session_name, api_id, api_hash, channel_username, source_name):
        self.session_name = session_name
        self.api_id = api_id
        self.api_hash = api_hash
        self.channel_username = channel_username
        self.source_name = source_name

    @classmethod
    def set_db_config(cls, config):
        cls.db_config = config

    def fetch_last_post(self):
        logging.info(f"[{self.source_name}] checking a new post...")

        try:
            with TelegramClient(self.session_name, self.api_id, self.api_hash) as client:
                entity = client.get_entity(self.channel_username)
                history = client(GetHistoryRequest(
                    peer=entity,
                    limit=1,
                    offset_date=None,
                    offset_id=0,
                    max_id=0,
                    min_id=0,
                    add_offset=0,
                    hash=0
                ))

                if history.messages:
                    msg = history.messages[0]
                    logging.info(f"[{self.source_name}] received a post: {msg.message[:60]}...")
                    self.save_to_db(self.source_name, msg.message)
                else:
                    logging.info(f"[{self.source_name}] there is no new messages")
        except Exception as e:
            logging.error(f"[{self.source_name}] error when receiving a post: {e}")

    def save_to_db(self, source, message):
        if not self.db_config:
            logging.error("DB config is not set")
            return

        try:
            conn = psycopg2.connect(**self.db_config)
            cur = conn.cursor()
            cur.execute(
                "INSERT INTO leaks (source, message) VALUES (%s, %s)",
                (source, message)
            )
            conn.commit()
            cur.close()
            conn.close()
            logging.info(f"[{self.source_name}] message is recorded in the database")
        except Exception as e:
            logging.error(f"[{self.source_name}] error when writing to the database: {e}")