// ─────────────────────────────────────────────────────────────
// public/entrance.js — client-side behaviour for the entrance page.
// Loaded via <script src="/entrance.js" defer></script> so CSP
// can stay at `script-src 'self'` — no inline scripts.
// ─────────────────────────────────────────────────────────────

/* ───── Topographic currents ───── */
(function drawCurrents() {
  const wrap = document.getElementById('currents');
  if (!wrap) return;
  const W = 1400, H = 1400, cx = W * 0.55, cy = H * 0.45;
  const svgNS = 'http://www.w3.org/2000/svg';
  const svg = document.createElementNS(svgNS, 'svg');
  svg.setAttribute('viewBox', `0 0 ${W} ${H}`);
  svg.setAttribute('preserveAspectRatio', 'xMidYMid meet');
  const RINGS = 26, BASE_R = 90, STEP = 32, AMP = 26;
  for (let i = 0; i < RINGS; i++) {
    const r = BASE_R + i * STEP, segs = 260;
    const p1 = (i * 0.6) % (Math.PI * 2);
    const p2 = (i * 1.3 + 1.2) % (Math.PI * 2);
    const a1 = AMP * (0.9 + (i % 5) * 0.08);
    const a2 = AMP * 0.35;
    let d = '';
    for (let s = 0; s <= segs; s++) {
      const t = (s / segs) * Math.PI * 2;
      const rr = r + a1 * Math.sin(t * 3 + p1 + i * 0.15)
                   + a2 * Math.sin(t * 5 + p2 + i * 0.22)
                   + AMP * 0.18 * Math.sin(t * 7 + i);
      const x = cx + Math.cos(t) * rr;
      const y = cy + Math.sin(t) * rr * 0.92;
      d += (s === 0 ? 'M' : 'L') + x.toFixed(1) + ' ' + y.toFixed(1);
    }
    d += ' Z';
    const path = document.createElementNS(svgNS, 'path');
    path.setAttribute('d', d);
    path.setAttribute('fill', 'none');
    path.setAttribute('stroke', '#383831');
    path.setAttribute('stroke-width', '1');
    path.setAttribute('stroke-linejoin', 'round');
    path.setAttribute('opacity', (i % 3 === 0 ? 0.095 : 0.055).toString());
    svg.appendChild(path);
  }
  wrap.appendChild(svg);
  requestAnimationFrame(() => setTimeout(() => wrap.classList.add('is-ready'), 120));
})();

/* ───── Step transitions ───── */
const steps = {
  email:   document.getElementById('step-email'),
  code:    document.getElementById('step-code'),
  welcome: document.getElementById('step-welcome'),
};
function showStep(name) {
  Object.entries(steps).forEach(([k, el]) => {
    el.classList.toggle('is-active', k === name);
  });
}

/* ───── Step 1: email ───── */
const emailForm  = document.getElementById('email-form');
const emailInput = document.getElementById('email-input');
const emailAck   = document.getElementById('email-ack');
let rememberedEmail = '';

function setAck(el, text, isError) {
  el.textContent = text;
  el.classList.toggle('is-error', !!isError);
  el.classList.toggle('is-visible', !!text);
}

emailInput.addEventListener('input', () => {
  emailInput.classList.remove('is-error');
  setAck(emailAck, '', false);
});

emailForm.addEventListener('submit', async (e) => {
  e.preventDefault();
  const email = emailInput.value.trim();
  if (!/^[^@\s]+@[^@\s]+\.[^@\s]+$/.test(email)) {
    emailInput.classList.add('is-error');
    setAck(emailAck, 'Please enter a valid email address.', true);
    return;
  }

  emailInput.disabled = true;
  setAck(emailAck, 'Sending\u2026', false);

  try {
    const res = await fetch('/auth/request-code', {
      method: 'POST',
      credentials: 'same-origin',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({ email }),
    });

    if (res.status === 429) {
      emailInput.disabled = false;
      setAck(emailAck, 'Too many attempts. Try again in a little while.', true);
      return;
    }
    if (!res.ok) {
      emailInput.disabled = false;
      setAck(emailAck, 'Something went wrong. Try again.', true);
      return;
    }
  } catch (err) {
    emailInput.disabled = false;
    setAck(emailAck, 'Could not reach the archive. Retry?', true);
    return;
  }

  rememberedEmail = email;
  setAck(emailAck, '', false);
  showStep('code');
  setTimeout(() => codeCells[0].focus(), 300);
});

/* ───── Step 2: code ───── */
const codeCells = Array.from(document.querySelectorAll('.code-cell'));
const codeForm  = document.getElementById('code-form');
const codeAck   = document.getElementById('code-ack');

function codeValue() { return codeCells.map(c => c.value).join(''); }

codeCells.forEach((cell, i) => {
  cell.addEventListener('input', () => {
    cell.value = cell.value.replace(/\D/g, '').slice(-1);
    cell.classList.toggle('is-filled', !!cell.value);
    cell.classList.remove('is-error');
    setAck(codeAck, '', false);
    if (cell.value && i < codeCells.length - 1) codeCells[i + 1].focus();
    if (codeValue().length === 6) submitCode();
  });
  cell.addEventListener('keydown', (e) => {
    if (e.key === 'Backspace' && !cell.value && i > 0) {
      codeCells[i - 1].focus();
      codeCells[i - 1].value = '';
      codeCells[i - 1].classList.remove('is-filled');
      e.preventDefault();
    } else if (e.key === 'ArrowLeft' && i > 0) { codeCells[i - 1].focus(); e.preventDefault(); }
    else if (e.key === 'ArrowRight' && i < codeCells.length - 1) { codeCells[i + 1].focus(); e.preventDefault(); }
  });
  cell.addEventListener('paste', (e) => {
    const text = (e.clipboardData || window.clipboardData).getData('text').replace(/\D/g, '');
    if (!text) return;
    e.preventDefault();
    for (let j = 0; j < codeCells.length; j++) {
      codeCells[j].value = text[j] || '';
      codeCells[j].classList.toggle('is-filled', !!codeCells[j].value);
    }
    (codeCells[Math.min(text.length, codeCells.length - 1)] || codeCells[0]).focus();
    if (codeValue().length === 6) submitCode();
  });
});

codeForm.addEventListener('submit', (e) => { e.preventDefault(); submitCode(); });

let submitting = false;
async function submitCode() {
  if (submitting) return;
  if (codeValue().length !== 6) return;
  submitting = true;
  codeCells.forEach(c => c.disabled = true);
  setAck(codeAck, 'Reading\u2026', false);

  try {
    const res = await fetch('/auth/verify-code', {
      method: 'POST',
      credentials: 'same-origin',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({ email: rememberedEmail, code: codeValue() }),
    });

    if (res.ok) {
      setAck(codeAck, '', false);
      showStep('welcome');
      return;
    }

    codeCells.forEach(c => { c.classList.add('is-error'); c.disabled = false; });
    if (res.status === 429) {
      setAck(codeAck, 'Too many attempts. Request a new code.', true);
    } else {
      setAck(codeAck, 'That code doesn\u2019t match. Try again.', true);
    }
    submitting = false;
  } catch (err) {
    codeCells.forEach(c => c.disabled = false);
    setAck(codeAck, 'Could not reach the archive. Retry?', true);
    submitting = false;
  }
}

document.getElementById('use-different').addEventListener('click', () => {
  codeCells.forEach(c => { c.value = ''; c.classList.remove('is-filled', 'is-error'); c.disabled = false; });
  setAck(codeAck, '', false);
  submitting = false;
  emailInput.disabled = false;
  emailInput.value = rememberedEmail;
  showStep('email');
  setTimeout(() => emailInput.focus(), 300);
});

/* ───── Step 3: welcome → timeline ───── */
document.getElementById('welcome-continue').addEventListener('click', () => {
  // Cross-document View Transitions animate this nav automatically on
  // supported browsers (Chrome/Safari). Firefox falls back to a plain nav.
  window.location.href = '/timeline';
});

/* ───── On-load routing ───── */
// `/` always serves this entrance shell. Decide which step to show based
// on whether the visitor already has a valid session.
(async function routeOnLoad() {
  let authed = false;
  try {
    const res = await fetch('/auth/me', { credentials: 'same-origin' });
    authed = res.ok;
  } catch { /* offline — fall through to email */ }

  if (authed) {
    showStep('welcome');
  } else {
    showStep('email');
    setTimeout(() => emailInput.focus(), 300);
  }
  document.body.classList.remove('is-pending');
})();