#!/usr/bin/env python3
# /// script
# requires-python = ">=3.10"
# dependencies = [
#   "telethon>=1.42",
#   "python-dotenv>=1.0",
# ]
# ///
"""
List broadcast channels and supergroups in a named Telegram folder (default: "Jobs").

Output: JSON array of usernames (falling back to numeric id for private channels) on stdout.

Pipe directly into the fetch script:
    list_telegram_channels.py | fetch_telegram_jobs.py -

Account: uses TELEGRAM_SESSION_STRING from .env — must be the usulsu (main) account.
The "Jobs" folder lives on that account.
"""

import asyncio
import json
import os
import sys
from pathlib import Path

from dotenv import load_dotenv
from telethon import TelegramClient
from telethon.sessions import StringSession
from telethon.tl.functions.messages import GetDialogFiltersRequest
from telethon.tl.types import Channel, InputPeerChannel

PROJECT_ROOT = Path(__file__).resolve().parent.parent
DEFAULT_FOLDER = "Jobs"


def filter_title(f):
    """DialogFilter.title is str on older Telethon, TextWithEntities on newer."""
    t = getattr(f, "title", None)
    if t is None:
        return ""
    return t if isinstance(t, str) else getattr(t, "text", "")


async def main(folder_title):
    load_dotenv(PROJECT_ROOT / ".env")
    try:
        api_id = int(os.environ["TELEGRAM_API_ID"])
        api_hash = os.environ["TELEGRAM_API_HASH"]
        session = os.environ["TELEGRAM_SESSION_STRING"]
    except KeyError as e:
        sys.exit(f"missing env var: {e}. check .env in project root.")

    async with TelegramClient(StringSession(session), api_id, api_hash) as client:
        result = await client(GetDialogFiltersRequest())

        target = None
        for f in result.filters:
            if filter_title(f) == folder_title:
                target = f
                break
        if target is None:
            sys.exit(f"folder {folder_title!r} not found")

        # Combine pinned + included peers — both are part of the folder
        wanted_channel_ids = set()
        for peer in list(getattr(target, "pinned_peers", []) or []) + list(target.include_peers):
            if isinstance(peer, InputPeerChannel):
                wanted_channel_ids.add(peer.channel_id)

        # Resolve channel entities to extract usernames
        usernames = []
        async for dialog in client.iter_dialogs():
            ent = dialog.entity
            if not isinstance(ent, Channel):
                continue
            if ent.id not in wanted_channel_ids:
                continue
            usernames.append(ent.username or str(-1000000000000 - ent.id))

        print(json.dumps(usernames, ensure_ascii=False))


if __name__ == "__main__":
    folder = sys.argv[1] if len(sys.argv) > 1 else DEFAULT_FOLDER
    asyncio.run(main(folder))