import { describe, expect, it } from 'vitest';
import { wallFaces } from './walls.js';
import { rectShape } from './shapes.js';

describe('wallFaces', () => {
  it('builds a quad strip around a rectangle', () => {
    const wall = wallFaces(rectShape(2, 2), 1);
    // 4 outline points * 2 vertices each.
    expect(wall.positions.length / 3).toBe(8);
    expect(wall.indices.length).toBe(4 * 6); // 4 quads * 2 triangles
  });

  it('has outward-facing normals', () => {
    const wall = wallFaces(rectShape(2, 2), 1);
    // Bottom edge (from (-1,-1) to (1,-1)) normal should point -Y.
    // First two vertices belong to the first outline point (-1,-1).
    const n = wall.normals.slice(0, 3);
    expect(n[0]).toBeCloseTo(0, 5);
    expect(n[1]).toBeCloseTo(-1, 5);
    expect(n[2]).toBeCloseTo(0, 5);
  });

  it('spans from z=0 to z=height', () => {
    const wall = wallFaces(rectShape(2, 2), 3);
    // First vertex is bottom (z=0), second is top (z=3).
    expect(wall.positions[2]).toBe(0);
    expect(wall.positions[5]).toBe(3);
  });

  it('uses planar UVs from the top face mapping, independent of z', () => {
    const wall = wallFaces(rectShape(2, 2), 2);
    // First outline point is (-1,-1) -> planar UV (0, 0).
    expect(wall.uvs[0]).toBeCloseTo(0, 5);
    expect(wall.uvs[1]).toBeCloseTo(0, 5);
    // The bottom and top vertices of the same outline point share a UV,
    // so the texture is constant down the wall regardless of z.
    expect(wall.uvs[2]).toBeCloseTo(wall.uvs[0]!, 5);
    expect(wall.uvs[3]).toBeCloseTo(wall.uvs[1]!, 5);
    // Third outline point is (1, 1) -> planar UV (1, 1).
    expect(wall.uvs[8]).toBeCloseTo(1, 5);
    expect(wall.uvs[9]).toBeCloseTo(1, 5);
  });
});