from __future__ import annotations

import math

# Clockwise from east, matching the y-down world convention used throughout (see camera.py).
_EIGHT_WAY_DIRECTIONS: tuple[tuple[int, int], ...] = (
    (1, 0),
    (1, 1),
    (0, 1),
    (-1, 1),
    (-1, 0),
    (-1, -1),
    (0, -1),
    (1, -1),
)


def snap_to_8way(dx: float, dy: float) -> tuple[int, int]:
    """Snaps a free direction to the nearest of the 8 compass directions.

    The mouse can point anywhere ("no fixed angles" while aiming), but combat/interaction still
    resolves against the tile grid, so this is where continuous aim meets discrete tile logic.
    """
    if dx == 0.0 and dy == 0.0:
        return 0, 1
    angle = math.atan2(dy, dx)
    index = round(angle / (math.pi / 4)) % 8
    return _EIGHT_WAY_DIRECTIONS[index]


def apply_cone_deviation(dx: int, dy: int, cone_degrees: float, rng) -> tuple[int, int]:
    """Randomly deviates a direction within +/- cone_degrees/2, snapped back to the grid.

    This is where "the exact direction of the shot is randomized" within the aim cone happens -
    the caller (e.g. perform_shoot) supplies the cone's size (from skill + weapon mods).
    """
    if cone_degrees <= 0:
        return dx, dy
    base_angle = math.atan2(dy, dx)
    deviation = math.radians(rng.uniform(-cone_degrees / 2, cone_degrees / 2))
    angle = base_angle + deviation
    return snap_to_8way(math.cos(angle), math.sin(angle))