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

/**
 * Tests for the Diff Panel pure helpers.
 *
 * The `createDiffPanel` factory is DOM-heavy and exercised via e2e tests.
 * Here we only cover the stringly helpers that decide how each version
 * option is rendered — particularly the Forge-aware branch.
 */

import { formatDiffOption, isForgeAuthored } from '../src/docs/diff-panel.js';

describe('formatDiffOption', () => {
  const recent = new Date(Date.now() - 5 * 60 * 1000).toISOString();

  it('tags forge-authored versions with [forge] prefix', () => {
    const out = formatDiffOption({ author: 'forge', label: 'Initial plan' }, recent);
    expect(out.startsWith('[forge]')).toBe(true);
    expect(out).toContain('Initial plan');
    expect(out).toContain('5 min ago');
  });

  it('prefers name over label when both present', () => {
    const out = formatDiffOption({ author: 'forge', name: 'Milestone 1', label: 'raw' }, recent);
    expect(out).toContain('Milestone 1');
    expect(out).not.toContain('raw');
  });

  it('falls back to "revision" when forge metadata has no label', () => {
    const out = formatDiffOption({ author: 'forge' }, recent);
    expect(out).toContain('[forge] revision');
  });

  it('uses legacy "time — author" format for human versions', () => {
    const out = formatDiffOption({ author: 'scott' }, recent);
    expect(out).toBe('5 min ago — scott');
    expect(out.startsWith('[forge]')).toBe(false);
  });

  it('uses "name (time)" when a human version has a name', () => {
    const out = formatDiffOption({ author: 'scott', name: 'Before rewrite' }, recent);
    expect(out).toBe('Before rewrite (5 min ago)');
  });

  it('defaults author to Unknown when missing', () => {
    const out = formatDiffOption({}, recent);
    expect(out).toContain('Unknown');
  });
});

describe('isForgeAuthored', () => {
  it('returns true for forge author', () => {
    expect(isForgeAuthored({ author: 'forge' })).toBe(true);
  });

  it('returns false for human authors', () => {
    expect(isForgeAuthored({ author: 'scott' })).toBe(false);
  });

  it('returns false when author is missing', () => {
    expect(isForgeAuthored({})).toBe(false);
  });

  it('returns false for non-string author values', () => {
    expect(isForgeAuthored({ author: 42 as unknown })).toBe(false);
  });
});