/**
 * Tests for embeddings utility — embedText + cosineSimilarity + stripHtmlForEmbedding.
 */

import { describe, it, expect, vi } from 'vitest';
import { cosineSimilarity, stripHtmlForEmbedding } from './embeddings.js';

vi.mock('./llm.js', () => ({
  llm: vi.fn(() => ({
    embed: vi.fn(async () => ({
      embeddings: [[0.1, 0.2, 0.3, 0.4, 0.5]],
      model: 'mock-embed',
      usage: { promptTokens: 5, completionTokens: 0, totalTokens: 5 },
    })),
  })),
}));
vi.mock('./config.js', () => ({
  config: { LLM_EMBEDDING_MODEL: 'text-embedding-3-small' },
}));

describe('cosineSimilarity', () => {
  it('returns 1 for identical vectors', () => {
    const v = [1, 2, 3, 4];
    expect(cosineSimilarity(v, v)).toBeCloseTo(1, 5);
  });

  it('returns 0 for orthogonal vectors', () => {
    expect(cosineSimilarity([1, 0], [0, 1])).toBeCloseTo(0, 5);
  });

  it('returns -1 for opposite vectors', () => {
    expect(cosineSimilarity([1, 0], [-1, 0])).toBeCloseTo(-1, 5);
  });

  it('returns 0 for empty vectors', () => {
    expect(cosineSimilarity([], [])).toBe(0);
  });

  it('returns 0 for mismatched lengths', () => {
    expect(cosineSimilarity([1, 2], [1, 2, 3])).toBe(0);
  });

  it('returns 0 for zero vectors', () => {
    expect(cosineSimilarity([0, 0, 0], [1, 2, 3])).toBe(0);
  });

  it('computes correct similarity for known vectors', () => {
    const a = [1, 2, 3];
    const b = [4, 5, 6];
    // dot = 4+10+18 = 32, |a| = sqrt(14), |b| = sqrt(77)
    const expected = 32 / (Math.sqrt(14) * Math.sqrt(77));
    expect(cosineSimilarity(a, b)).toBeCloseTo(expected, 5);
  });
});

describe('stripHtmlForEmbedding', () => {
  it('strips HTML tags', () => {
    expect(stripHtmlForEmbedding('<p>Hello <b>world</b></p>')).toBe('Hello world');
  });

  it('collapses whitespace', () => {
    expect(stripHtmlForEmbedding('Hello   \n\n  world')).toBe('Hello world');
  });

  it('handles empty string', () => {
    expect(stripHtmlForEmbedding('')).toBe('');
  });

  it('strips complex HTML', () => {
    const html = '<div class="note"><h1>Title</h1><p>Content with <a href="#">link</a></p></div>';
    expect(stripHtmlForEmbedding(html)).toBe('Title Content with link');
  });
});

describe('embedText', () => {
  it('returns embedding vector', async () => {
    const { embedText } = await import('./embeddings.js');
    const result = await embedText('hello world');
    expect(result).toEqual([0.1, 0.2, 0.3, 0.4, 0.5]);
  });
});