/**
 * Tests for fixSvgNamespaces utility
 *
 * Root cause: mermaid.render() returns SVG with xlink:href attributes (used by
 * C4Context person icons) but without xmlns:xlink namespace declaration.
 * DOMParser.parseFromString(svg, 'image/svg+xml') is a strict XML parser —
 * it fails on undeclared namespace prefixes and returns a <parsererror> element.
 * This causes C4Context diagrams to render as a blank white box.
 *
 * mermaid.run() (live editor) does include xmlns:xlink, so it works fine.
 * Only mermaid.render() (static site via init-mermaid.js) is affected.
 *
 * Run with: `pnpm test` (uses tsx + node:test — no vitest, no happy-dom).
 *
 * NOTE: The 3 DOMParser/`document` tests that were here under the
 * "DOMParser integration" describe block were dropped when we moved off
 * happy-dom. Their own comment already acknowledged: "happy-dom is lenient
 * and parses it anyway, so we cannot replicate that specific Chrome failure
 * here. The string-level tests above are the authoritative verification that
 * the fix adds the declaration that Chrome requires."
 */

import { describe, it } from 'node:test';
import assert from 'node:assert/strict';
import { fixSvgNamespaces } from '../src/svg-utils.js';

// Minimal SVG that mermaid.render() produces for a typical C4Context diagram.
// Critical detail: has xlink:href (from person icon <image> elements) but
// NO xmlns:xlink declaration — this is what mermaid.render() actually outputs.
const C4_SVG_WITHOUT_XMLNS = `<svg id="mermaid-svg-0" width="100%" xmlns="http://www.w3.org/2000/svg" viewBox="0 0 650 400">
<style>#mermaid-svg-0 .node{fill:#08427B}</style>
<g>
  <rect x="10" y="10" width="200" height="100" fill="#08427B"/>
  <image width="48" height="48" x="91" y="20" xlink:href="data:image/png;base64,iVBORw0KGgo="/>
  <text x="110" y="90" fill="white">Customer</text>
</g>
</svg>`;

// Same SVG but already has xmlns:xlink — should not be modified
const C4_SVG_WITH_XMLNS = `<svg id="mermaid-svg-0" width="100%" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" viewBox="0 0 650 400">
<style>#mermaid-svg-0 .node{fill:#08427B}</style>
<g>
  <image width="48" height="48" x="91" y="20" xlink:href="data:image/png;base64,iVBORw0KGgo="/>
</g>
</svg>`;

// Flowchart SVG — no xlink: usage at all, should not be modified
const FLOWCHART_SVG_NO_XLINK = `<svg id="mermaid-svg-1" width="100%" xmlns="http://www.w3.org/2000/svg" viewBox="0 0 400 200">
<style>#mermaid-svg-1 .node rect{fill:#36bcf7}</style>
<g>
  <rect x="10" y="10" width="100" height="40"/>
  <text x="60" y="35">Start</text>
</g>
</svg>`;

// Flowchart with clickable links — also uses xlink:href (less common but possible)
const FLOWCHART_SVG_WITH_LINK = `<svg id="mermaid-svg-2" width="100%" xmlns="http://www.w3.org/2000/svg" viewBox="0 0 400 200">
<a xlink:href="https://example.com" target="_blank">
  <rect x="10" y="10" width="100" height="40"/>
</a>
</svg>`;

describe('fixSvgNamespaces', () => {
  describe('C4Context person icon (root cause scenario)', () => {
    it('adds xmlns:xlink when SVG uses xlink:href without declaration', () => {
      const fixed = fixSvgNamespaces(C4_SVG_WITHOUT_XMLNS);

      assert.ok(fixed.includes('xmlns:xlink="http://www.w3.org/1999/xlink"'));
    });

    it('places xmlns:xlink inside the <svg> opening tag', () => {
      const fixed = fixSvgNamespaces(C4_SVG_WITHOUT_XMLNS);

      // Must be on <svg>, not somewhere else
      assert.match(fixed, /<svg[^>]+xmlns:xlink="http:\/\/www\.w3\.org\/1999\/xlink"/);
    });

    it('preserves all existing SVG content unchanged', () => {
      const fixed = fixSvgNamespaces(C4_SVG_WITHOUT_XMLNS);

      assert.ok(fixed.includes('xlink:href="data:image/png;base64,iVBORw0KGgo="'));
      assert.ok(fixed.includes('xmlns="http://www.w3.org/2000/svg"'));
      assert.ok(fixed.includes('viewBox="0 0 650 400"'));
      assert.ok(fixed.includes('<text x="110" y="90" fill="white">Customer</text>'));
    });
  });

  describe('idempotency — does not break already-valid SVG', () => {
    it('returns SVG unchanged when xmlns:xlink is already declared', () => {
      const fixed = fixSvgNamespaces(C4_SVG_WITH_XMLNS);

      assert.equal(fixed, C4_SVG_WITH_XMLNS);
    });

    it('does not duplicate xmlns:xlink when called twice', () => {
      const fixed = fixSvgNamespaces(fixSvgNamespaces(C4_SVG_WITHOUT_XMLNS));

      const count = (fixed.match(/xmlns:xlink/g) ?? []).length;
      assert.equal(count, 1);
    });
  });

  describe('non-C4 diagrams — no false positives', () => {
    it('returns flowchart SVG unchanged when no xlink: is used', () => {
      const fixed = fixSvgNamespaces(FLOWCHART_SVG_NO_XLINK);

      assert.equal(fixed, FLOWCHART_SVG_NO_XLINK);
      assert.ok(!fixed.includes('xmlns:xlink'));
    });

    it('adds xmlns:xlink for flowchart with clickable links (also uses xlink:href)', () => {
      const fixed = fixSvgNamespaces(FLOWCHART_SVG_WITH_LINK);

      assert.ok(fixed.includes('xmlns:xlink="http://www.w3.org/1999/xlink"'));
    });
  });
});