"""Discord Rich Presence integration for Tunetti."""

import logging
import threading
import time
from typing import Optional

from pypresence import Presence, DiscordNotFound
from pypresence.types import ActivityType

log = logging.getLogger("tunetti.rpc")


def _safe_artists(song: Optional[dict]) -> str:
    """Extract a comma-separated artist string, handling None / missing keys."""
    if not song:
        return ""
    artists = song.get("artists")
    if not isinstance(artists, list):
        return ""
    names = []
    for a in artists:
        if isinstance(a, dict):
            name = a.get("name", "")
            if name:
                names.append(name)
    return ", ".join(names)


class DiscordRPC:
    """Manages Discord Rich Presence for the currently playing song.

    Presence updates are normally batched every ``REFRESH_INTERVAL``
    seconds, but calling :meth:`update_song` immediately signals the
    background loop to send the new state right away.
    """

    REFRESH_INTERVAL = 15  # seconds between re-sends

    def __init__(self, client_id: str):
        self._client_id = client_id
        self._rpc: Optional[Presence] = None
        self._connected = False
        self._song: Optional[dict] = None
        self._start_ts: Optional[int] = None
        self._lock = threading.Lock()
        self._thread: Optional[threading.Thread] = None
        self._stop_event = threading.Event()
        self._wake_event = threading.Event()

    # ------------------------------------------------------------------
    # Lifecycle
    # ------------------------------------------------------------------
    def start(self) -> None:
        """Connect to Discord and start the background update loop."""
        if self._thread and self._thread.is_alive():
            return
        self._stop_event.clear()
        self._wake_event.clear()
        self._thread = threading.Thread(target=self._run, daemon=True,
                                        name="discord-rpc")
        self._thread.start()

    def stop(self) -> None:
        self._stop_event.set()
        self._wake_event.set()
        if self._thread:
            self._thread.join(timeout=3)
        self._disconnect()

    # ------------------------------------------------------------------
    # Public update
    # ------------------------------------------------------------------
    def update_song(self, song: Optional[dict],
                    reset_start: bool = True) -> None:
        """Set the currently playing song (or None to clear).

        When *reset_start* is ``True`` (default), the start timestamp
        is set to now so Discord shows a fresh progress bar.  Pass
        ``False`` on resume to keep the original start time.

        The presence is sent to Discord *immediately*.
        """
        with self._lock:
            self._song = song
            if reset_start:
                self._start_ts = int(time.time()) if song else None
        self._wake_event.set()

    def clear(self) -> None:
        """Clear the presence entirely."""
        with self._lock:
            self._song = None
            self._start_ts = None
        self._wake_event.set()

    def seek_to(self, position_ms: int) -> None:
        """Recalculate start_ts after a seek so Discord's progress bar
        shows the correct elapsed time from the new position."""
        with self._lock:
            if self._start_ts is not None:
                self._start_ts = int(time.time()) - (position_ms // 1000)
        self._wake_event.set()

    # ------------------------------------------------------------------
    # Internal
    # ------------------------------------------------------------------
    def _connect(self) -> bool:
        try:
            self._rpc = Presence(self._client_id)
            self._rpc.connect()
            self._connected = True
            log.info("Connected to Discord RPC")
            return True
        except DiscordNotFound:
            log.warning("Discord not running – RPC unavailable")
            self._connected = False
            return False
        except Exception as exc:
            log.debug("Discord RPC connect failed: %s", exc)
            self._connected = False
            return False

    def _disconnect(self) -> None:
        if self._rpc:
            try:
                self._rpc.close()
            except Exception:
                pass
        self._rpc = None
        self._connected = False

    def _send_presence(self) -> None:
        with self._lock:
            song = self._song
            start = self._start_ts

        if not song:
            if self._connected and self._rpc is not None:
                try:
                    self._rpc.clear()
                except Exception:
                    self._connected = False
            return

        artists_str = _safe_artists(song)
        title = song.get("title", "Unknown")
        thumbnail = song.get("thumbnail") or ""
        duration = song.get("duration", 0)

        end_ts = (start + duration) if start and duration else None

        if self._rpc is None:
            return

        try:
            self._rpc.update(
                activity_type=ActivityType.LISTENING,
                details=title,
                state=f"by {artists_str}" if artists_str else "YouTube Music",
                large_image=thumbnail,
                start=start,
                end=end_ts,
            )
        except Exception as exc:
            log.debug("RPC update failed: %s", exc)
            self._connected = False

    def _run(self) -> None:
        while not self._stop_event.is_set():
            if not self._connected:
                self._connect()
                if not self._connected:
                    self._stop_event.wait(10)
                    continue

            self._send_presence()
            # Wait for either the refresh interval or an immediate wake-up
            self._wake_event.wait(self.REFRESH_INTERVAL)
            self._wake_event.clear()

        self._disconnect()