# core/bot_downloader.py

Handles "click to download" inline button flows. Some Telegram channels post files via a bot behind a button rather than directly attaching them.

## Public API

```python
from core.bot_downloader import (
    handle_bot_download_message,
    has_download_button,
    extract_password,
)
```

### `handle_bot_download_message(client, bot, msg, source_name, patterns, password=None)`
**async.** Full pipeline:
1. Detect download button
2. Click it (URL button → `/start payload` to the bot; callback button → `.click()`)
3. Wait up to `BOT_REPLY_TIMEOUT` seconds for the bot to send a file back
4. Hand each file response to `core.scraper.handle_message()`

### `has_download_button(msg) -> bool`
Returns `True` if the message contains a recognisable download button.  
Checked in live handler and backfill before calling this module.

### `extract_password(msg) -> str | None`
Scans message text for `Pass: ...` / `Password: ...` / `Contraseña: ...` patterns.  
Returns the extracted password string, or `None`.

---

## Button detection

Recognised button text keywords (case-insensitive):
```
DOWNLOAD, DESCARGAR, GET FILE, GET PACK, ⬇, 📥
```

---

## URL button flow (most common)

```
Button URL: https://t.me/SomeBot?start=ABC123
  → parse bot username + payload
  → client.send_message(bot_entity, "/start ABC123")
  → poll get_messages(bot_entity, limit=3) every 1s for BOT_REPLY_TIMEOUT seconds
  → return file messages found
```

## Callback button flow (fallback)

```
btn.click()
→ sleep 2s
→ get_messages(sender, limit=5)
→ return file messages found
```

---

## Constants

| Name | Value | Description |
|------|-------|-------------|
| `BOT_REPLY_TIMEOUT` | `10` | Seconds to wait for bot file reply |
| `DOWNLOAD_BUTTON_KEYWORDS` | see above | Button text triggers |
| `PASSWORD_PATTERN` | regex | Matches `Pass[word]: value` in message text |