import {countries,provinces,personal,corporate,sources,reviewed} from './data.mjs';
import {amount,percentage,progressive,sales,company} from './engine.mjs';
const $=s=>document.querySelector(s);
const form=$('#tax-form');let mode='income';let activeScope='',activePeriod='';
const escape=s=>String(s).replace(/[&<>"']/g,c=>({'&':'&amp;','<':'&lt;','>':'&gt;','"':'&quot;',"'":'&#39;'}[c]));
const country=()=>countries.find(c=>c.code===$('#country').value);
const money=n=>new Intl.NumberFormat('en',{style:'currency',currency:country().currency,maximumFractionDigits:2}).format(n);
const select=(id,label,options)=>`<div class="tax-field"><label for="${id}">${label}</label><select id="${id}" name="${id}">${options.map(([v,t])=>`<option value="${v}">${escape(t)}</option>`).join('')}</select></div>`;
const rateField=()=>'<div class="tax-field" id="custom-wrap"><label for="custom-rate">Verified combined tax rate (%)</label><input id="custom-rate" type="number" min="0" max="100" step="0.001" required placeholder="Enter the applicable rate"><p class="tax-help">Confirm the rate with the authority. This is arithmetic using your rate, not an automatic tax determination.</p></div>';
$('#country').innerHTML='<optgroup label="Countries">'+countries.filter(c=>!c.eu).map(c=>`<option value="${c.code}">${c.name}</option>`).join('')+'</optgroup><optgroup label="European Union">'+countries.filter(c=>c.eu).map(c=>`<option value="${c.code}">${c.name}</option>`).join('')+'</optgroup>';
$('#country').value='AU';
function clearResult(){
 $('#result').innerHTML='<p class="tax-kicker">Your calculation</p><h2>Make the numbers clear.</h2><p>Confirm the scope and calculate to see a breakdown.</p>';
 $('#error').textContent='';
}
function configure(){
 clearResult();$('#confirm').checked=false;
 const c=country(),data=(mode==='income'?personal:corporate)[c.code];let options='',links=[];let available=true;
 if(mode==='sales'){
  activePeriod='Rate snapshot reviewed 21 September 2026 · current transactions only';
  activeScope='Domestic transactions only. You must confirm the place of supply and product classification. Excludes imports, cross-border/reverse-charge transactions, special territories, excise duties, tax credits and registration rules.';
  if(c.eu){
   options+=select('rate-choice','VAT treatment',[['standard',`Standard VAT — ${c.vat}%`],['custom','Reduced / special rate — enter verified rate']]);
   options+=rateField();links.push(['European Commission VAT rates (source updated 13 July 2026)',sources.euVAT],['National tax rules and special territories',sources.euTax]);
   activeScope+=' Standard rate only is preset. Regional exceptions and reduced-rate eligibility are not determined. Do not use the national standard rate for special territories.';
  }else if(c.code==='CA'){
   options+=select('province','Place of supply — province / territory',provinces.map(p=>[p[0],p[1]]));
   options+=select('rate-choice','Treatment',[['standard','Ordinary supply subject to GST/HST and PST/QST'],['custom','Special / reduced treatment — enter verified combined rate']]);options+=rateField();
   links.push(['CRA GST/HST and provincial rate table',sources.caSales]);
   activeScope+=' Provincial and federal amounts use the same pre-tax base. Product-specific PST/QST exemptions are not determined.';
  }else if(c.code==='AU'){
   options+=select('rate-choice','GST treatment',[['standard','Ordinary taxable supply — 10% GST'],['custom','Other treatment — enter verified rate']]);options+=rateField();links.push(['Australian Government GST guidance',sources.auSales]);
  }else if(c.code==='IN'){
   options+=select('rate-choice','GST treatment',[['18','Standard rate — 18%'],['5','Merit rate — 5%'],['40','Special de-merit rate — 40%'],['custom','Other verified rate']]);
   options+=select('supply','Supply type',[['intra','Within the same state — CGST + SGST'],['inter','Between states — IGST']]);options+=rateField();links.push(['Government of India GST reform announcement',sources.inSales]);
   activeScope+=' These are rate presets, not an HSN/SAC classification service. Special goods, valuation rules and additional cesses are excluded.';
  }else{
   options+=rateField();links.push(['US state tax authority directory',sources.usSales]);
   activeScope='US sales tax has no single nationwide rate. This mode only performs arithmetic with the combined state/local rate YOU enter. It does not look up an address, establish nexus, determine exemptions or validate a rate. Check the destination jurisdiction and product before using it.';
  }
  options+=select('price-mode','The entered amount is',[['exclusive','Before tax — add tax'],['inclusive','Including tax — extract tax']]);
  $('#amount-label').textContent=`Transaction amount (${c.currency})`;$('#amount-help').textContent='Use the transaction currency shown. This tool does not convert currencies.';
 }else if(data){
  activePeriod=data.period;activeScope=data.note;links.push(['Official rules for this calculation',data.source]);
  options=select('profile',mode==='income'?'Supported taxpayer profile':'Supported company profile',data.profiles.map(p=>[p.id,p.label]));
  $('#amount-label').textContent=mode==='income'?`Annual taxable income (${c.currency})`:`Eligible taxable profit (${c.currency})`;
  $('#amount-help').textContent=mode==='income'?'Use taxable income after deductions. Do not enter gross salary or subtract deductions twice.':'Use taxable profit after permitted deductions, not revenue or turnover. Eligibility must already be established.';
 }else{
  available=false;activePeriod='National rules not yet verified in this calculator';
  activeScope=`${c.name} ${mode==='income'?'personal income':'company'} tax is not available yet. Regional rules, deductions and reliefs have not been implemented and verified. No numerical estimate will be shown. Use the official national tax database below.`;
  links.push(['European Commission — national tax rules',sources.euTax]);
 }
 $('#options').innerHTML=options;
 $('#period').textContent=activePeriod;$('#scope').textContent=activeScope;
 $('#amount').closest('.tax-field').hidden=!available;$('#amount').disabled=!available;
 $('.tax-confirm').hidden=!available;$('#confirm').disabled=!available;$('#calculate').disabled=!available;
 $('#sources').innerHTML=links.map(([label,url])=>`<li><a href="${url}" target="_blank" rel="noopener noreferrer">${escape(label)} ↗</a></li>`).join('');
 const stale=Date.now()-Date.parse(reviewed)>90*86400000;
 $('#reviewed').textContent=`Source review: ${reviewed}. ${stale?'This snapshot is over 90 days old. Recheck the authority before relying on it.':'Each result uses the tax period shown above.'}`;
 if(!available)$('#result').innerHTML='<p class="tax-kicker">Coverage</p><h2>Not available yet.</h2><p>No tax amount has been calculated. Follow the official source below for this country.</p>';
 updateCustom();
}
function updateCustom(){const el=$('#custom-wrap');if(!el)return;const visible=!$('#rate-choice')||$('#rate-choice').value==='custom';el.hidden=!visible;$('#custom-rate').disabled=!visible;}
function fieldRow(label,value){return `<div class="tax-row"><span>${escape(label)}</span><strong>${escape(value)}</strong></div>`;}
form.addEventListener('submit',e=>{
 e.preventDefault();$('#error').textContent='';
 try{
  if(!form.reportValidity())return;
  if(!$('#confirm').checked)throw new Error('Confirm that your circumstances match the supported scope.');
  const c=country(),value=amount($('#amount').value);let title='',total=0,body='';
  if(mode==='sales'){
   const custom=$('#custom-rate')&&!$('#custom-rate').disabled;
   let rates,labels;
   if(custom){rates=[percentage($('#custom-rate').value)];labels=['Tax using your supplied rate'];}
   else if(c.eu){rates=[c.vat];labels=['Standard VAT'];}
   else if(c.code==='CA'){const p=provinces.find(p=>p[0]===$('#province').value);rates=[p[2],p[3]];labels=['GST / HST',p[0]==='QC'?'QST':'PST'];}
   else if(c.code==='AU'){rates=[10];labels=['GST'];}
   else if(c.code==='IN'){const rate=percentage($('#rate-choice').value);rates=$('#supply').value==='intra'?[rate/2,rate/2]:[rate];labels=rates.length===2?['CGST','SGST / UTGST']:['IGST'];}
   else throw new Error('Enter your verified combined tax rate.');
   const result=sales(value,rates,$('#price-mode').value==='inclusive');total=result.total;title=custom?'Tax at your supplied rate':'Estimated transaction tax';
   body=fieldRow('Price before tax',money(result.base))+result.rows.map((r,i)=>fieldRow(`${labels[i]} (${r.rate}%)`,money(r.tax))).join('')+fieldRow('Price including tax',money(result.gross));
   body+='<p>Rounded to two decimal places. Invoice-level rounding or special valuation rules can differ.</p>';
  }else{
   const data=(mode==='income'?personal:corporate)[c.code];
   if(!data)throw new Error('This country and tax type are not supported yet.');
   const p=data.profiles.find(p=>p.id===$('#profile').value);if(!p)throw new Error('Choose a supported profile.');
   if(mode==='income'){
    const r=progressive(value,p.bands);total=r.total;title='Basic bracket tax only';
    body=fieldRow('Taxable income entered',money(value))+fieldRow('Bracket tax / taxable income',`${value?(total/value*100).toFixed(2):'0.00'}%`);
    body+='<div class="tax-table-wrap"><table><caption>Tax by income band</caption><thead><tr><th>Band starts at</th><th>Rate</th><th>Tax</th></tr></thead><tbody>'+r.rows.filter(r=>r.base>0).map(r=>`<tr><td>${money(r.lower)}</td><td>${r.rate}%</td><td>${money(r.tax)}</td></tr>`).join('')+'</tbody></table></div>';
    body+='<p><strong>Before the adjustments listed below. This is not total tax or take-home pay.</strong></p>';
   }else{
    const r=company(value,p);total=r.total;title='Estimated company tax component';
    body=fieldRow('Eligible taxable profit',money(value))+fieldRow(`Basic tax (${p.rate}%)`,money(r.basic));
    if(p.surcharge)body+=fieldRow(`Surcharge (${p.surcharge}% of basic tax)`,money(r.surcharge));
    if(p.cess)body+=fieldRow(`Cess (${p.cess}% of tax + surcharge)`,money(r.cess));
   }
  }
  $('#result').innerHTML=`<p class="tax-kicker">${escape(c.name)} · ${escape(activePeriod)}</p><h2>${title}</h2><output class="tax-total">${money(total)}</output>${body}<p class="result-scope"><strong>Included / excluded</strong><br>${escape(activeScope)}</p>`;
 }catch(err){clearResult();$('#error').textContent=err.message;}
});
$('#country').addEventListener('change',()=>{$('#amount').value='';configure();});
form.addEventListener('input',e=>{if(e.target.id!=='country')clearResult();});
$('#options').addEventListener('change',()=>{updateCustom();clearResult();$('#confirm').checked=false;});
const tabs=[...document.querySelectorAll('[data-mode]')];
function activate(tab){mode=tab.dataset.mode;tabs.forEach(t=>{const on=t===tab;t.setAttribute('aria-selected',String(on));t.tabIndex=on?0:-1;});$('#tax-panel').setAttribute('aria-labelledby',tab.id);$('#amount').value='';configure();}
tabs.forEach((tab,i)=>{tab.addEventListener('click',()=>activate(tab));tab.addEventListener('keydown',e=>{let n;if(e.key==='ArrowRight')n=(i+1)%tabs.length;else if(e.key==='ArrowLeft')n=(i+tabs.length-1)%tabs.length;else if(e.key==='Home')n=0;else if(e.key==='End')n=tabs.length-1;else return;e.preventDefault();tabs[n].focus();activate(tabs[n]);});});
configure();