#!/usr/bin/env node

import fs from 'fs';
import path from 'path';

const CLEAN_CONTENT_REGEX = {
  comments: /\/\*[\s\S]*?\*\/|\/\/.*$/gm,
  templateLiterals: /`[\s\S]*?`/g,
  strings: /'[^']*'|"[^"]*"/g,
  jsxExpressions: /\{.*?\}/g,
  htmlEntities: {
    quot: /"/g,
    amp: /&/g,
    lt: /</g,
    gt: />/g,
    apos: /'/g
  }
};

const EXTRACTION_REGEX = {
  route: /<Route\s+[^>]*>/g,
  path: /path=["']([^"']+)["']/,
  element: /element=\{<(\w+)[^}]*\/?\s*>\}/,
  helmet: /<Helmet[^>]*?>([\s\S]*?)<\/Helmet>/i,
  helmetTest: /<Helmet[\s\S]*?<\/Helmet>/i,
  title: /<title[^>]*?>\s*(.*?)\s*<\/title>/i,
  description: /<meta\s+name=["']description["']\s+content=["'](.*?)["']/i
};

function cleanContent(content) {
  return content
    .replace(CLEAN_CONTENT_REGEX.comments, '')
    .replace(CLEAN_CONTENT_REGEX.templateLiterals, '""')
    .replace(CLEAN_CONTENT_REGEX.strings, '""');
}

function cleanText(text) {
  if (!text) return text;

  return text
    .replace(CLEAN_CONTENT_REGEX.jsxExpressions, '')
    .replace(CLEAN_CONTENT_REGEX.htmlEntities.quot, '"')
    .replace(CLEAN_CONTENT_REGEX.htmlEntities.amp, '&')
    .replace(CLEAN_CONTENT_REGEX.htmlEntities.lt, '<')
    .replace(CLEAN_CONTENT_REGEX.htmlEntities.gt, '>')
    .replace(CLEAN_CONTENT_REGEX.htmlEntities.apos, "'")
    .trim();
}

function extractRoutes(appJsxPath) {
  if (!fs.existsSync(appJsxPath)) return new Map();

  try {
    const content = fs.readFileSync(appJsxPath, 'utf8');
    const routes = new Map();
    const routeMatches = [...content.matchAll(EXTRACTION_REGEX.route)];

    for (const match of routeMatches) {
      const routeTag = match[0];
      const pathMatch = routeTag.match(EXTRACTION_REGEX.path);
      const elementMatch = routeTag.match(EXTRACTION_REGEX.element);
      const isIndex = routeTag.includes('index');

      if (elementMatch) {
        const componentName = elementMatch[1];
        let routePath;

        if (isIndex) {
          routePath = '/';
        } else if (pathMatch) {
          routePath = pathMatch[1].startsWith('/') ? pathMatch[1] : `/${pathMatch[1]}`;
        }

        routes.set(componentName, routePath);
      }
    }

    return routes;
  } catch (error) {
    return new Map();
  }
}

function findReactFiles(dir) {
  return fs.readdirSync(dir).map(item => path.join(dir, item));
}

function extractHelmetData(content, filePath, routes) {
  const cleanedContent = cleanContent(content);

  if (!EXTRACTION_REGEX.helmetTest.test(cleanedContent)) {
    return null;
  }

  const helmetMatch = content.match(EXTRACTION_REGEX.helmet);
  if (!helmetMatch) return null;

  const helmetContent = helmetMatch[1];
  const titleMatch = helmetContent.match(EXTRACTION_REGEX.title);
  const descMatch = helmetContent.match(EXTRACTION_REGEX.description);

  const title = cleanText(titleMatch?.[1]);
  const description = cleanText(descMatch?.[1]);

  const fileName = path.basename(filePath, path.extname(filePath));
  const url = routes.length && routes.has(fileName)
    ? routes.get(fileName)
    : generateFallbackUrl(fileName);

  return {
    url,
    title: title || 'Untitled Page',
    description: description || 'No description available'
  };
}

function generateFallbackUrl(fileName) {
  const cleanName = fileName.replace(/Page$/, '').toLowerCase();
  return cleanName === 'app' ? '/' : `/${cleanName}`;
}

function generateLlmsTxt(pages) {
  const sortedPages = pages.sort((a, b) => a.title.localeCompare(b.title));
  const pageEntries = sortedPages.map(page =>
    `- [${page.title}](${page.url}): ${page.description}`
  ).join('\n');

  return `## Pages\n${pageEntries}`;
}

function ensureDirectoryExists(dirPath) {
  if (!fs.existsSync(dirPath)) {
    fs.mkdirSync(dirPath, { recursive: true });
  }
}

function processPageFile(filePath, routes) {
  try {
    const content = fs.readFileSync(filePath, 'utf8');
    return extractHelmetData(content, filePath, routes);
  } catch (error) {
    console.error(`❌ Error processing ${filePath}:`, error.message);
    return null;
  }
}

function main() {
  const pagesDir = path.join(process.cwd(), 'src', 'pages');
  const appJsxPath = path.join(process.cwd(), 'src', 'App.jsx');

  let pages = [];

  if (!fs.existsSync(pagesDir)) {
    pages.push(processPageFile(appJsxPath, []));
  } else {
    const routes = extractRoutes(appJsxPath);
    const reactFiles = findReactFiles(pagesDir);

    pages = reactFiles
      .map(filePath => processPageFile(filePath, routes))
      .filter(Boolean);

    if (pages.length === 0) {
      console.error('❌ No pages with Helmet components found!');
      process.exit(1);
    }
  }


  const llmsTxtContent = generateLlmsTxt(pages);
  const outputPath = path.join(process.cwd(), 'public', 'llms.txt');

  ensureDirectoryExists(path.dirname(outputPath));
  fs.writeFileSync(outputPath, llmsTxtContent, 'utf8');
}

const isMainModule = import.meta.url === `file://${process.argv[1]}`;

if (isMainModule) {
  main();
}