"""Temporary visual effects that appear on the map and fade over time."""

import time
from dataclasses import dataclass


@dataclass
class Effect:
    """A temporary visual overlay on the world map."""

    x: int
    y: int
    char: str
    color: str  # ANSI color code
    expires_at: float  # monotonic time when this effect disappears


# Global list of active effects
active_effects: list[Effect] = []


def add_effect(x: int, y: int, char: str, color: str, ttl: float) -> None:
    """Add a temporary visual effect at (x, y).

    Args:
        x: World X coordinate
        y: World Y coordinate
        char: Character to display
        color: ANSI color code for rendering
        ttl: Time to live in seconds
    """
    active_effects.append(
        Effect(x=x, y=y, char=char, color=color, expires_at=time.monotonic() + ttl)
    )


def get_effects_at(x: int, y: int) -> list[Effect]:
    """Get all non-expired effects at a given position."""
    now = time.monotonic()
    return [e for e in active_effects if e.x == x and e.y == y and e.expires_at > now]


def clear_expired() -> None:
    """Remove all expired effects from the active list."""
    now = time.monotonic()
    active_effects[:] = [e for e in active_effects if e.expires_at > now]