import { describe, test, expect } from 'bun:test';
import { _cosine } from './vector-only.ts';

// Note: VectorOnlyAdapter.init/query require a live embedding API key.
// Those end-to-end tests live in a smoke-test class and gate on OPENAI_API_KEY.
// Here we unit-test the pure-function pieces.

describe('vector-only adapter (pure helpers)', () => {
  test('cosine of identical vectors = 1.0', () => {
    const a = new Float32Array([1, 2, 3, 4]);
    const b = new Float32Array([1, 2, 3, 4]);
    expect(_cosine(a, b)).toBeCloseTo(1.0, 6);
  });

  test('cosine of opposite vectors = -1.0', () => {
    const a = new Float32Array([1, 2, 3]);
    const b = new Float32Array([-1, -2, -3]);
    expect(_cosine(a, b)).toBeCloseTo(-1.0, 6);
  });

  test('cosine of orthogonal vectors = 0', () => {
    const a = new Float32Array([1, 0, 0]);
    const b = new Float32Array([0, 1, 0]);
    expect(_cosine(a, b)).toBeCloseTo(0.0, 6);
  });

  test('cosine handles zero vector by returning 0', () => {
    const a = new Float32Array([0, 0, 0]);
    const b = new Float32Array([1, 2, 3]);
    expect(_cosine(a, b)).toBe(0);
  });

  test('cosine is scale-invariant', () => {
    const a = new Float32Array([1, 2, 3]);
    const b = new Float32Array([2, 4, 6]);
    // Same direction, different magnitudes; cosine should still be 1.
    expect(_cosine(a, b)).toBeCloseTo(1.0, 6);
  });

  test('cosine returns 0 on mismatched-length vectors at the tail', () => {
    // Uses min(len) — shorter vector's dimensions are compared, longer's
    // extras are implicitly dropped. Produces a sensible number even
    // when upstream glue has a dim mismatch bug; helps fail-soft rather
    // than crash the benchmark.
    const a = new Float32Array([1, 1, 1]);
    const b = new Float32Array([1, 1]);
    const sim = _cosine(a, b);
    expect(sim).toBeGreaterThan(0);
    expect(sim).toBeLessThanOrEqual(1);
  });
});