from __future__ import annotations

import threading
import time
from dataclasses import dataclass, field
from typing import Dict, Optional, Set


def server_time_ms() -> float:
    """High-resolution server time in milliseconds."""
    return time.time_ns() / 1_000_000.0


@dataclass
class ActiveEventState:
    event_id: int
    name: str
    start_time_ms: float
    end_time_ms: Optional[float]
    # public_id -> video_url
    assignments: Dict[str, str]


_lock = threading.Lock()
_trigger: Optional[ActiveEventState] = None
_trigger_ended: Set[str] = set()


def set_trigger_event(state: Optional[ActiveEventState]) -> None:
    global _trigger, _trigger_ended
    with _lock:
        _trigger = state
        _trigger_ended = set()


def get_current_event(now_ms: Optional[float] = None) -> Optional[ActiveEventState]:
    """Returns current active trigger event if any."""
    global _trigger
    with _lock:
        if now_ms is None:
            now_ms = server_time_ms()

        if _trigger is not None and _trigger.end_time_ms is not None and now_ms > _trigger.end_time_ms:
            _trigger = None
            _trigger_ended.clear()

        return _trigger


def get_trigger_event(now_ms: Optional[float] = None) -> Optional[ActiveEventState]:
    global _trigger
    with _lock:
        if _trigger is None:
            return None
        if now_ms is None:
            now_ms = server_time_ms()
        if _trigger.end_time_ms is not None and now_ms > _trigger.end_time_ms:
            _trigger = None
            _trigger_ended.clear()
            return None
        return _trigger


def mark_trigger_display_ended(event_id: int, public_id: str) -> bool:
    """Marks a display as ended for the current trigger event.

    Returns True if this completes the event (all displays ended) and the trigger is cleared.
    """
    global _trigger, _trigger_ended
    with _lock:
        if _trigger is None or _trigger.event_id != event_id:
            return False
        _trigger_ended.add(public_id)
        if len(_trigger_ended) >= len(_trigger.assignments):
            _trigger = None
            _trigger_ended = set()
            return True
        return False


def clear_trigger_event() -> None:
    global _trigger, _trigger_ended
    with _lock:
        _trigger = None
        _trigger_ended = set()