// ==========================================
// ChatPane Kit — Markdown Renderer
// ==========================================
// Wraps window.marked + window.DOMPurify with fallback.
// Independently importable utility.
//
// v0.37.10: Task list rendering, code block language extraction.
//
// Usage:
//   import { renderMarkdown } from './markdown.js';
//   const html = renderMarkdown('**bold** text');

let _lastInput = '';
let _lastOutput = '';

const _escMap = { '&': '&amp;', '<': '&lt;', '>': '&gt;', '"': '&quot;', "'": '&#39;' };

function _escapeHtml(text) {
    return text.replace(/[&<>"']/g, c => _escMap[c]);
}

/**
 * Configure marked with task list support if available.
 */
let _configured = false;
function _ensureConfigured() {
    if (_configured) return;
    _configured = true;
    if (typeof marked === 'undefined') return;

    marked.setOptions({
        breaks: true,
        gfm: true,
    });

    // Custom renderer for task list items
    const renderer = new marked.Renderer();
    const origListItem = renderer.listitem?.bind(renderer);
    renderer.listitem = function(text, task, checked) {
        if (task) {
            const checkbox = checked
                ? '<input type="checkbox" checked disabled class="sw-task-checkbox" />'
                : '<input type="checkbox" disabled class="sw-task-checkbox" />';
            return '<li class="sw-task-item">' + checkbox + ' ' + text + '</li>\n';
        }
        if (origListItem) return origListItem(text, task, checked);
        return '<li>' + text + '</li>\n';
    };

    marked.use({ renderer });
}

/**
 * Render markdown text to sanitized HTML.
 * Falls back to escaped plaintext when marked/DOMPurify unavailable.
 *
 * @param {string} text — raw markdown
 * @returns {string} sanitized HTML
 */
export function renderMarkdown(text) {
    if (!text) return '';
    if (text === _lastInput) return _lastOutput;

    let result;
    if (typeof marked !== 'undefined' && typeof DOMPurify !== 'undefined') {
        _ensureConfigured();
        result = DOMPurify.sanitize(marked.parse(text));
    } else {
        result = _escapeHtml(text);
    }

    _lastInput = text;
    _lastOutput = result;
    return result;
}