"""
tui_events.py — Thread-safe event bus between the bot backend and the TUI.

The bot backend runs in a dedicated thread with its own asyncio event loop
(completely isolated from Textual's loop).  Events are posted via a standard
queue.Queue (thread-safe), and the TUI consumer polls it from Textual's loop
using asyncio.get_event_loop().run_in_executor() bridging.

post() is safe to call from any thread or any asyncio loop.
"""

import queue
import threading
from dataclasses import dataclass, field
from typing import Any

# Thread-safe queue — works across the bot thread and Textual's thread.
_queue: queue.Queue | None = None
_queue_lock = threading.Lock()

# Set to True when the TUI is running so tdl pipes output instead of
# writing directly to the terminal.
tui_active: bool = False


def init_bus() -> queue.Queue:
    """Call once from MonitorApp.on_mount() to create the queue."""
    global _queue, tui_active
    _queue = queue.Queue()
    tui_active = True
    return _queue


def get_bus() -> queue.Queue | None:
    return _queue


def post(event: Any) -> None:
    """Fire-and-forget from any thread. Silently drops if bus not up."""
    if _queue is not None:
        try:
            _queue.put_nowait(event)
        except queue.Full:
            pass


# ─── Event types ──────────────────────────────────────────────────────────────

@dataclass
class EvDownloadQueued:
    """A file has been accepted and is waiting for tdl."""
    batch_id:  str
    filename:  str
    size_mb:   float
    source:    str
    password:  str | None


@dataclass
class EvDownloadStarted:
    """tdl has begun transferring this file."""
    batch_id:  str
    filename:  str


@dataclass
class EvDownloadDone:
    """File fully downloaded (tdl or Telethon fallback)."""
    batch_id:  str
    filename:  str
    via:       str   # "tdl" | "telethon"


@dataclass
class EvDownloadFailed:
    """All download attempts failed."""
    batch_id:  str
    filename:  str
    reason:    str


@dataclass
class EvTdlOutput:
    """A line of output from tdl's stdout/stderr (TUI mode only)."""
    line: str


@dataclass
class EvHit:
    """A scored credential hit to display in the hits panel."""
    severity:  str
    raw:       str
    source:    str
    filename:  str
    reasons:   list[str] = field(default_factory=list)


@dataclass
class EvChannelAdded:
    """A channel was added to the live watch list."""
    channel: str | int


@dataclass
class EvChannelRemoved:
    """A channel was removed from the live watch list."""
    channel: str | int


@dataclass
class EvStatus:
    """Generic one-line status message (startup, errors, etc.)."""
    text: str
    level: str = "info"   # "info" | "warning" | "error"