import { describe, expect, it } from 'vitest';
import { safeLinkTargetUrl } from '../src/lib/url';

describe('safeLinkTargetUrl', () => {
  it('returns http and https URLs unchanged', () => {
    expect(safeLinkTargetUrl('https://example.com')).toBe('https://example.com');
    expect(safeLinkTargetUrl('http://example.com/path?q=1')).toBe('http://example.com/path?q=1');
  });

  it('is case-insensitive for the scheme', () => {
    expect(safeLinkTargetUrl('HTTPS://Example.COM')).toBe('HTTPS://Example.COM');
    expect(safeLinkTargetUrl('HtTp://example.com')).toBe('HtTp://example.com');
  });

  it('returns null for javascript: URLs', () => {
    expect(safeLinkTargetUrl('javascript:alert(1)')).toBeNull();
  });

  it('returns null for data: URLs', () => {
    expect(safeLinkTargetUrl('data:text/html,<script>alert(1)</script>')).toBeNull();
  });

  it('returns null for other non-http schemes', () => {
    expect(safeLinkTargetUrl('mailto:foo@bar.com')).toBeNull();
    expect(safeLinkTargetUrl('ftp://example.com')).toBeNull();
    expect(safeLinkTargetUrl('file:///etc/passwd')).toBeNull();
  });

  it('returns null for scheme-relative and protocol-relative URLs', () => {
    expect(safeLinkTargetUrl('//example.com')).toBeNull();
    expect(safeLinkTargetUrl('/local/path')).toBeNull();
  });

  it('returns null for null and empty input', () => {
    expect(safeLinkTargetUrl(null)).toBeNull();
    expect(safeLinkTargetUrl('')).toBeNull();
  });

  it('returns null for whitespace-only or malformed input', () => {
    expect(safeLinkTargetUrl('   ')).toBeNull();
    expect(safeLinkTargetUrl('example.com')).toBeNull();
  });
});