/**
 * Unit tests for render.js partitioning, export, and bounded history helpers.
 */

import { test, describe } from 'node:test';
import assert from 'node:assert/strict';
import {
  partitionMarkdown,
  renderMarkdownSectionToFragment,
  SECTION_TARGET_BYTES,
  SECTION_HARD_LIMIT_BYTES,
  PATHOLOGICAL_BLOCK_LIMIT,
  getUtf8Bytes
} from '../js/render.js';
import { serializeBounded } from '../js/history.js';

describe('Render module helpers and partition logic', () => {
  test('partitionMarkdown returns single section for normal sized text', () => {
    const text = '# Small Document\n\nThis is a short markdown text.';
    const sections = partitionMarkdown(text);
    assert.equal(sections.length, 1);
    assert.equal(sections[0].text, text);
  });

  test('partitionMarkdown splits large documents at heading/blank line boundaries', () => {
    // Generate text exceeding SECTION_TARGET_BYTES (~48 KiB)
    const part1 = '# Section One\n' + 'Content line.\n'.repeat(3500);
    const part2 = '# Section Two\n' + 'More content line.\n'.repeat(3500);
    const combined = `${part1}\n\n${part2}`;

    const sections = partitionMarkdown(combined);
    assert.ok(sections.length >= 2, 'Large text should be partitioned into at least 2 sections');
    assert.ok(sections[0].text.includes('Section One'));
    assert.ok(sections[1].text.includes('Section Two'));
  });

  test('partitionMarkdown forces split inside giant 12 MB code fence and re-opens fence', () => {
    // 12 MB code fence (runtime probe from H1)
    const line = 'const val = 1234567890;\n';
    const linesCount = Math.ceil((12 * 1024 * 1024) / line.length);
    const codeBlock = '```typescript\n' + line.repeat(linesCount) + '```\n';

    const sections = partitionMarkdown(codeBlock);
    assert.ok(sections.length > 100, `12 MB fence must be split into multiple sections, got ${sections.length}`);

    // Every section must stay strictly bounded
    for (let i = 0; i < sections.length; i++) {
      const secBytes = getUtf8Bytes(sections[i].text);
      assert.ok(secBytes <= SECTION_HARD_LIMIT_BYTES + 1024, `Section ${i} size ${secBytes} must be <= hard limit`);

      // Each section must be a valid closed code block
      const text = sections[i].text.trim();
      assert.ok(text.startsWith('```typescript'), `Section ${i} must open with code fence`);
      assert.ok(text.endsWith('```'), `Section ${i} must close with code fence`);
    }
  });

  test('partitionMarkdown splits dense 2.2 MB list with no blank lines into bounded sections', () => {
    // 2.2 MB dense list (runtime probe from H1)
    const listItem = '- Item with detailed specification text and metadata\n';
    const itemsCount = Math.ceil((2.2 * 1024 * 1024) / listItem.length);
    const denseList = listItem.repeat(itemsCount);

    const sections = partitionMarkdown(denseList);
    assert.ok(sections.length >= 30, `2.2 MB dense list must be partitioned, got ${sections.length} sections`);

    for (let i = 0; i < sections.length; i++) {
      const secBytes = getUtf8Bytes(sections[i].text);
      assert.ok(secBytes <= SECTION_HARD_LIMIT_BYTES + 512, `Section ${i} size ${secBytes} must not exceed hard limit`);
    }
  });

  test('partitionMarkdown partitions ~122 MB simulated answer into bounded sections', () => {
    // 122 MB simulated answer (from H1 runtime probe)
    // Construct in chunks to avoid single-line issues
    const chunk = '# Header\n' + 'Paragraph content line for analysis.\n'.repeat(1000); // ~37 KB
    const chunkBytes = getUtf8Bytes(chunk);
    const repetitions = Math.ceil((122 * 1024 * 1024) / chunkBytes);
    const hugeDoc = chunk.repeat(repetitions);

    const sections = partitionMarkdown(hugeDoc);
    assert.ok(sections.length >= 1000, `122 MB document must partition into >1000 sections, got ${sections.length}`);
    for (let i = 0; i < Math.min(20, sections.length); i++) {
      assert.ok(getUtf8Bytes(sections[i].text) <= SECTION_HARD_LIMIT_BYTES + 512);
    }
  });

  test('partitionMarkdown splits large tables at row boundaries and repeats table headers', () => {
    const header = '| Column 1 | Column 2 | Column 3 |\n|---|---|---|\n';
    const row = '| data alpha | data beta | data gamma |\n';
    const table = header + row.repeat(3000); // ~120 KB

    const sections = partitionMarkdown(table);
    assert.ok(sections.length >= 2, 'Large table should partition into multiple sections');

    // Section 2 should continue with repeated table header
    assert.ok(sections[1].text.includes('| Column 1 | Column 2 | Column 3 |'), 'Subsequent section must repeat table header');
    assert.ok(sections[1].text.includes('|---|---|---|'), 'Subsequent section must repeat table separator');
  });

  test('partitionMarkdown handles multibyte UTF-8 byte boundary correctly', () => {
    // 4-byte UTF-8 emoji
    const emojiLine = '🚀'.repeat(500) + '\n'; // 2000 bytes per line
    const multibyteDoc = emojiLine.repeat(40); // 80,000 bytes

    const sections = partitionMarkdown(multibyteDoc);
    assert.ok(sections.length >= 2, 'Should partition multibyte document based on byte size');
    for (const sec of sections) {
      assert.ok(getUtf8Bytes(sec.text) <= SECTION_HARD_LIMIT_BYTES + 2048);
    }
  });

  test('partitionMarkdown falls back to bounded plain-text for single pathological line', () => {
    // Single line exceeding 128 KiB
    const hugeLine = 'A'.repeat(150 * 1024);
    const sections = partitionMarkdown(hugeLine);
    assert.ok(sections.length >= 1);
    assert.ok(sections[0].isPathologicalFallback);
    assert.ok(sections[0].text.includes('Block truncated for performance'));
    assert.ok(sections[0].text.length < 35 * 1024);
  });

  test('renderMarkdownSectionToFragment fails safe when marked or DOMPurify absent', () => {
    // In Node test environment, window.marked and window.DOMPurify are undefined
    const rawUntrusted = '<script>alert("xss")</script><img src="x" onerror="alert(1)">';
    const fragment = renderMarkdownSectionToFragment(rawUntrusted);

    // Must return a safe DocumentFragment containing the render error notice, NEVER raw innerHTML
    assert.ok(fragment);
    if (typeof document !== 'undefined') {
      const notice = fragment.querySelector('.render-error-notice');
      assert.ok(notice, 'Must contain error notice when parser/sanitizer is absent');
      assert.ok(!fragment.querySelector('script'), 'Must never inject script tags');
      assert.ok(!fragment.querySelector('img'), 'Must never inject img tags');
    }
  });

  test('serializeBounded bounds huge 10 MB objects to <= 32 KiB without memory exhaustion', () => {
    const hugeObject = {
      title: 'Large Tool Result',
      markdown: 'x'.repeat(10 * 1024 * 1024), // 10 MB string
      items: Array.from({ length: 50000 }, (_, i) => ({ id: i, name: `item_${i}` }))
    };

    const serialized = serializeBounded(hugeObject, 32 * 1024);
    assert.ok(serialized.length <= 34 * 1024, `Serialized result length ${serialized.length} must be bounded around 32 KB`);
    assert.ok(serialized.includes('Result display bounded to 32.0 KB'), 'Must include truncation indicator');
  });
});