import { describe, expect, it } from "vitest";
import { stepFearedMobAway } from "./mobMotion";

describe("feared mob steering", () => {
  it("moves away from the player without changing floor height or crossing the leash", () => {
    const current: [number, number, number] = [2, 7, 0];
    const threat = [0, 4, 0] as const;
    const home = [0, 7, 0] as const;

    const moved = stepFearedMobAway(current, threat, home, 2, 3, current);
    const awayFromThreat = [current[0] - threat[0], current[2] - threat[2]];
    const originalAway = [2 - threat[0], 0 - threat[2]];
    const directionDot = awayFromThreat[0] * originalAway[0]
      + awayFromThreat[1] * originalAway[1];

    expect(moved).toBeCloseTo(1);
    expect(directionDot).toBeGreaterThan(0);
    expect(current[1]).toBe(7);
    expect(Math.hypot(current[0] - home[0], current[2] - home[2])).toBeCloseTo(3);
  });

  it("uses a deterministic direction when the mob and player overlap", () => {
    const out: [number, number, number] = [0, 0, 0];
    stepFearedMobAway([0, 2, 0], [0, 2, 0], [0, 2, 0], 0.5, 5, out);
    expect(out).toEqual([0.5, 2, 0]);
  });

  it("keeps malformed or zero-step input stationary and finite", () => {
    const out: [number, number, number] = [9, 9, 9];
    expect(stepFearedMobAway([1, 2, 3], [0, 0, 0], [0, 0, 0], Number.NaN, 4, out)).toBe(0);
    expect(out).toEqual([1, 2, 3]);
    expect(Object.values(out).every(Number.isFinite)).toBe(true);
  });
});