const fs = require('fs');
const path = require('path');
const { execSync } = require('child_process');
const docPath = process.cwd();
const vReg = /v([0-9].){2}[0-9]/;
const tReg = /#{1,4} /g;
const idReg = /---$(.*\n){1,10}---$/gm;

let menuPaths = [];
let labelKeys;

//pdf destination path
const pdfPath = path.join(__dirname, "../..", 'export_pdf');
if (!fs.existsSync(pdfPath)) {
  fs.mkdirSync(pdfPath);  
}

//released version
const versions = fs.readdirSync(docPath).filter(v => {
  if(vReg.test(v)) {
    const versionPath = path.join(docPath, v);
    const versionInfoPath = path.join(versionPath, "version.json");
    let versionInfo;
    try {
      versionInfo = fs.readFileSync(versionInfoPath);
      const info = JSON.parse(versionInfo.toString());
      if(info.released === 'yes') {
        setMenuPaths(versionPath, menuPaths);
        return true;
      }
    } catch (e) {
      console.log(`${versionInfoPath} read file error ${e.message}`);
      return false;
    }
  }
  return false;
});

menuPaths = menuPaths.flat();

console.log("versions",versions);
console.log("menuPaths",menuPaths);

menuPaths.forEach(fileRoute => {
  const fRoutes = fileRoute.split("/");
  fRoutes.pop();
  fRoutes.pop();
  const rootPath = fRoutes.join("/");
  const lang = fRoutes.pop();
  fRoutes.pop();
  const version = fRoutes.pop();

  const markdownPaths = [];
  const menuCotent = fs.readFileSync(fileRoute);
  const menuObj = JSON.parse(menuCotent.toString()).menuList.filter(m => !m.outLink);
  const formattedMenu = [];

  // get all label keys
  if (labelKeys === undefined) {
    labelKeys =
      menuObj.length > 0
        ? Object.keys(menuObj[0])
          .filter(v => v.includes('label'))
          .sort((a, b) => a[a.length - 1] - b[b.length - 1])
        : [];
  }
  // extract root menu 
  for (let i = 0; i < menuObj.length; i++) {
    if (menuObj[i][labelKeys[0]] == '') {
      formattedMenu.push(menuObj[i]);
      menuObj.splice(i, 1);
      i--;
    }
  }

  // order root menu item by order
  formattedMenu.sort((a, b) => {
    if (a.order < b.order) {
      return -1;
    }
    if (a.order > b.order) {
      return 1;
    }
    throw new Error(`set correct order in ${fileRoute} ${a.id}, ${b.id}`);
  });

  // order sub menu item by label1, lable2, label3 and order
  menuObj.sort((a, b) => {
    for (const key of labelKeys.concat('order')) {
      if (a[key] < b[key]) {
        return -1;
      }
      if (a[key] > b[key]) {
        return 1;
      }
    }
    throw new Error(`set correct order in ${fileRoute} ${a.id}, ${b.id}`);
  });

  // set submenu
  menuObj.forEach(subMenu => {
    setSubmenu(formattedMenu, subMenu, 0);
  });

  // set markdown path
  setMarkDownPath(rootPath, markdownPaths);

  // generate doc
  const res = [];
  generateDoc(formattedMenu, markdownPaths, res, 1);

  const mdFileName = `doc_milvus_${version}_${lang}`;
  const mdPath = path.join(rootPath, 'export');
  if (!fs.existsSync(mdPath)) {
     fs.mkdirSync(mdPath);
  } 
  const mdFile = path.join(mdPath, `${mdFileName}.md`);
  fs.writeFileSync(mdFile, res.join('\n'));
  console.log("mdPath", mdPath);

  const pandoccmd = `pandoc --toc --toc-depth=2 -s --resource-path=${mdPath} -f markdown+link_attributes -V geometry:"left=2cm, top=2cm, right=2cm, bottom=2cm" -V title="Milvus ${version}" -V mainfont="Symbola" -V CJKmainfont="AR PL SungtiL GB"  --pdf-engine=xelatex -o  ${pdfPath}/${mdFileName}.pdf ${mdFile}`
  const std  = execSync(pandoccmd);
  console.log(`stdout:\n${std}`);
  console.log(`${mdFile} file transfered to pdf`);
});

function generateDoc(menu, paths, res, level) {
  menu.forEach(m => {
    res.push(`${"#".repeat(level)} ${m.title}  `)
    if (m.id.endsWith('.md')) {
      const filePath = paths.filter(p => p.endsWith(m.id))[0];
      if (filePath === undefined) {
        const fRoutes = paths[0].split("/");
        fRoutes.pop();
        fRoutes.pop();
        throw new Error(`menu item ${JSON.stringify(m)} not found in ${fRoutes.join('/')}`);
      }
      const fileContent = fs.readFileSync(filePath).toString();
      res.push(replacetitle(fileContent, m.title));
    }
    if (m?.child?.length > 0) {
      generateDoc(m.child, paths, res, level + 1)
    }
  });
}

function replacetitle(content, title) {
  const titleReg = new RegExp(`#{1,2} ${title}( *)\n`);
  // remove all main title since we already generate title by toc
  content = content.replace(titleReg, '');

  // remove all code so that they can be shown properly
  // content = content.replace(/```/g, '');

  content = content.replace(/f"\\n/g, 'f"');

  // replace all sub title h1,h2,h3 by h3 to avoid them appear in toc
  content = content.replace(tReg, "### ");

  // remove all custom keys
  content = content.replace(idReg, "");
  return content;
}

function setMarkDownPath(dirPath, list) {
  let filesList = fs.readdirSync(dirPath);
  for (let i = 0; i < filesList.length; i++) {
    let filePath = path.join(dirPath, filesList[i]);
    if (filePath.endsWith('.md') && !filePath.includes("export_pdf")) {
      list.push(filePath);
    } else {
      let stats = fs.statSync(filePath);
      if (stats.isDirectory()) {
        setMarkDownPath(filePath, list);
      }
    }
  }
}

function setSubmenu(parents, child, level) {
  const parent1 = parents.filter(p => p.id === child[labelKeys[level]]);
  const parent = parent1[0];
  if (!parent) {
    return;
  }
  if (!child[labelKeys[level + 1]]) {
    if (parent.child === undefined) {
      parent.child = [];
    }
    parent.child.push(child);
    return;
  }
  if (!labelKeys[level + 1]) {
    return;
  }
  setSubmenu(parent.child, child, level + 1);
}

function setMenuPaths(dirPath, list) {
  let filesList = fs.readdirSync(dirPath);
  for (let i = 0; i < filesList.length; i++) {
    let filePath = path.join(dirPath, filesList[i]);
    if (filePath.endsWith('menuStructure')) {
      list.push(fs.readdirSync(filePath).map(f => path.join(filePath, f)));
    } else {
      let stats = fs.statSync(filePath);
      if (stats.isDirectory()) {
        setMenuPaths(filePath, list);
      }
    }
  }
}