import { describe, expect, it } from 'vitest';

import {
  angleTo,
  clamp,
  clampLength,
  directionFromKeys,
  distance,
  inCircle,
  length,
  normalize,
  rotate,
} from '../../app/static/js/logic/math.js';
import { createRng, pick, randFloat, randInt } from '../../app/static/js/logic/rng.js';

describe('math', () => {
  it('clamp begrenzt Werte', () => {
    expect(clamp(5, 0, 3)).toBe(3);
    expect(clamp(-1, 0, 3)).toBe(0);
    expect(clamp(2, 0, 3)).toBe(2);
  });

  it('normalize lässt den Nullvektor unverändert', () => {
    expect(normalize({ x: 0, y: 0 })).toEqual({ x: 0, y: 0 });
    expect(length(normalize({ x: 3, y: 4 }))).toBeCloseTo(1);
  });

  it('clampLength kürzt nur zu lange Vektoren', () => {
    expect(length(clampLength({ x: 30, y: 40 }, 10))).toBeCloseTo(10);
    expect(clampLength({ x: 1, y: 1 }, 10)).toEqual({ x: 1, y: 1 });
  });

  it('rotate und angleTo passen zusammen', () => {
    const r = rotate({ x: 1, y: 0 }, Math.PI / 2);
    expect(r.x).toBeCloseTo(0);
    expect(r.y).toBeCloseTo(1);
    expect(angleTo({ x: 0, y: 0 }, { x: 0, y: 5 })).toBeCloseTo(Math.PI / 2);
  });

  it('inCircle berücksichtigt die Ausdehnung des Objekts', () => {
    expect(inCircle({ x: 110, y: 0 }, { x: 0, y: 0 }, 100)).toBe(false);
    expect(inCircle({ x: 110, y: 0 }, { x: 0, y: 0 }, 100, 12)).toBe(true);
    expect(distance({ x: 0, y: 0 }, { x: 3, y: 4 })).toBe(5);
  });

  it('directionFromKeys normalisiert Diagonalen (8-Wege-Bewegung)', () => {
    expect(directionFromKeys({ up: true, down: false, left: false, right: false })).toEqual({ x: 0, y: -1 });
    const diag = directionFromKeys({ up: true, down: false, left: false, right: true });
    expect(length(diag)).toBeCloseTo(1);
    expect(diag.x).toBeGreaterThan(0);
    expect(diag.y).toBeLessThan(0);
    expect(directionFromKeys({ up: true, down: true, left: true, right: true })).toEqual({ x: 0, y: 0 });
  });
});

describe('rng', () => {
  it('ist mit gleichem Seed deterministisch und liegt in [0, 1)', () => {
    const a = createRng(123);
    const b = createRng(123);
    for (let i = 0; i < 1000; i += 1) {
      const value = a();
      expect(value).toBe(b());
      expect(value).toBeGreaterThanOrEqual(0);
      expect(value).toBeLessThan(1);
    }
  });

  it('randInt deckt die Grenzen ab und bleibt im Intervall', () => {
    const rng = createRng(7);
    const seen = new Set();
    for (let i = 0; i < 500; i += 1) {
      const n = randInt(rng, 1, 3);
      expect(n).toBeGreaterThanOrEqual(1);
      expect(n).toBeLessThanOrEqual(3);
      seen.add(n);
    }
    expect(seen).toEqual(new Set([1, 2, 3]));
  });

  it('randFloat und pick verhalten sich korrekt', () => {
    const rng = createRng(9);
    const f = randFloat(rng, 5, 6);
    expect(f).toBeGreaterThanOrEqual(5);
    expect(f).toBeLessThan(6);
    expect(['a', 'b']).toContain(pick(rng, ['a', 'b']));
    expect(() => pick(rng, [])).toThrow();
  });
});