const fs = require('fs');
const path = require('path');
const dir = path.join(__dirname, '..', '..', 'frontend', 'textbooks');
const files = ['geometry_10_hub.html','geometry_10_r1.html','geometry_10_r2.html','geometry_10_r3.html','geometry_10_r4.html'];

const cmds = ['dfrac','sqrt','sin','cos','tan','angle','vec','triangle','Rightarrow','cdot','ne','le','ge','pi','alpha','beta','gamma','delta','varphi','circ','perp','parallel','frac','tfrac','overline','left','right','begin','end','boxed','cot','arcsin','arccos','arctan','log','ln','lim','sum','int','infty','Delta','theta','lambda','mu','rho','sigma','tau','omega','Omega','phi','psi','xi','zeta','eta','epsilon','varepsilon','Pi','Sigma','approx','equiv','pm','mp','times','div','leq','geq','neq','sim','cong','subset','supset','cup','cap','forall','exists','overrightarrow','overleftarrow','widehat','widetilde','mathbf','mathrm','mathbb','mathcal','quad','qquad','hline','cline','displaystyle','textstyle','scriptstyle','underline','operatorname','land','lor','lnot','mapsto','Leftrightarrow','Leftarrow','leftarrow','rightarrow','uparrow','downarrow','prime','colon'];

for (const f of files) {
  const fp = path.join(dir, f);
  if (!fs.existsSync(fp)) { console.log('MISSING', f); continue; }
  const txt = fs.readFileSync(fp, 'utf8');

  const scriptRe = /<script(?![^>]*\bsrc=)[^>]*>([\s\S]*?)<\/script>/g;
  let m;
  let totalKatexErrs = 0;
  const errSamples = [];
  let scriptBlocks = 0;
  let combinedJs = '';

  while ((m = scriptRe.exec(txt)) !== null) {
    scriptBlocks++;
    const body = m[1];
    combinedJs += body + ';\n';
    const cmdRe = /(^|[^\\])\\([a-zA-Z]+)/g;
    let cm;
    while ((cm = cmdRe.exec(body)) !== null) {
      const cmd = cm[2];
      if (cmds.includes(cmd)) {
        totalKatexErrs++;
        const idxAbs = m.index + cm.index + cm[1].length;
        const before = txt.slice(0, idxAbs);
        const line = (before.match(/\n/g) || []).length + 1;
        if (errSamples.length < 10) errSamples.push({line, cmd, ctx: body.slice(Math.max(0,cm.index-30), cm.index+50).replace(/\n/g,' ')});
      }
    }
  }

  // <option> raw KaTeX
  const optRe = /<option[^>]*>([\s\S]*?)<\/option>/g;
  let om;
  let optionRaw = 0;
  const optionSamples = [];
  while ((om = optRe.exec(txt)) !== null) {
    const content = om[1];
    if (/\$[^\$]+\$/.test(content) || /\\(dfrac|sqrt|frac|angle|vec|sin|cos|alpha|beta|pi|circ|triangle|Rightarrow)/.test(content)) {
      optionRaw++;
      const before = txt.slice(0, om.index);
      const line = (before.match(/\n/g) || []).length + 1;
      if (optionSamples.length < 8) optionSamples.push({line, content: content.slice(0,90)});
    }
  }

  // Emoji
  const emojiRe = /[\u{1F300}-\u{1FAFF}\u{1F000}-\u{1F02F}\u{2700}-\u{27BF}\u{2600}-\u{26FF}]/gu;
  let em;
  let emoji = 0;
  const emojiSamples = [];
  while ((em = emojiRe.exec(txt)) !== null) {
    emoji++;
    const before = txt.slice(0, em.index);
    const line = (before.match(/\n/g) || []).length + 1;
    if (emojiSamples.length < 10) emojiSamples.push({line, ch: em[0], cp: em[0].codePointAt(0).toString(16), ctx: txt.slice(Math.max(0,em.index-25), em.index+25).replace(/\n/g,' ')});
  }

  let authors = [];
  if (f.includes('hub')) {
    for (const a of ['Латотин','Чеботаревский','Горбунова','Шлыков']) {
      if (txt.includes(a)) authors.push(a);
    }
  }

  let parseErr = null;
  try { new Function(combinedJs); } catch(e) { parseErr = e.message.slice(0,200); }

  console.log('=== ' + f + ' ===');
  console.log('  size:', txt.length, 'scripts:', scriptBlocks);
  console.log('  KaTeX single-backslash errors:', totalKatexErrs);
  for (const s of errSamples) console.log('    line ' + s.line + '  \\' + s.cmd + '  ctx: ' + s.ctx);
  console.log('  <option> raw KaTeX:', optionRaw);
  for (const s of optionSamples) console.log('    line ' + s.line + ': ' + s.content);
  console.log('  Emoji symbols:', emoji);
  for (const s of emojiSamples) console.log('    line ' + s.line + ' U+' + s.cp + ' ctx: ' + s.ctx);
  if (authors.length) console.log('  Authors in hub:', authors.join(', '));
  console.log('  JS parse:', parseErr ? 'ERROR: ' + parseErr : 'OK');
}