// ── Tab switching ─────────────────────────────────────────────────
const tabBtns = document.querySelectorAll('.tab-btn');
const sections = document.querySelectorAll('section');

function showTab(name) {
  sections.forEach(s => s.classList.toggle('active', s.id === name));
  tabBtns.forEach(b => b.classList.toggle('active', b.dataset.tab === name && !b.classList.contains('btn-launch')));
  if (name === 'dashboard') refreshStats();
  window.scrollTo({ top: 0, behavior: 'smooth' });
}

tabBtns.forEach(btn => {
  btn.addEventListener('click', () => showTab(btn.dataset.tab));
});

// ── Upload handling ──────────────────────────────────────────────
const uploadZone = document.getElementById('uploadZone');
const fileInput = document.getElementById('fileInput');
const previewRow = document.getElementById('previewRow');
const previewThumb = document.getElementById('previewThumb');
const previewName = document.getElementById('previewName');
const previewSize = document.getElementById('previewSize');
const clearBtn = document.getElementById('clearBtn');
const scanBtn = document.getElementById('scanBtn');
const verdictCard = document.getElementById('verdictCard');

let selectedFile = null;

uploadZone.addEventListener('click', () => fileInput.click());

uploadZone.addEventListener('dragover', e => { e.preventDefault(); uploadZone.classList.add('dragover'); });
uploadZone.addEventListener('dragleave', () => uploadZone.classList.remove('dragover'));
uploadZone.addEventListener('drop', e => {
  e.preventDefault();
  uploadZone.classList.remove('dragover');
  if (e.dataTransfer.files.length) handleFile(e.dataTransfer.files[0]);
});

fileInput.addEventListener('change', () => {
  if (fileInput.files.length) handleFile(fileInput.files[0]);
});

function handleFile(file) {
  selectedFile = file;
  previewName.textContent = file.name;
  previewSize.textContent = `${(file.size / (1024 * 1024)).toFixed(2)} MB · ${file.type.startsWith('video') ? 'Video' : 'Image'}`;

  const url = URL.createObjectURL(file);
  if (file.type.startsWith('video')) {
    previewThumb.outerHTML = `<video id="previewThumb" src="${url}" muted></video>`;
  } else {
    if (previewThumb.tagName !== 'IMG') {
      document.getElementById('previewThumb').outerHTML = `<img id="previewThumb" src="${url}" />`;
    } else {
      previewThumb.src = url;
    }
  }

  previewRow.style.display = 'flex';
  scanBtn.disabled = false;
  verdictCard.classList.remove('show');
}

clearBtn.addEventListener('click', () => {
  selectedFile = null;
  fileInput.value = '';
  previewRow.style.display = 'none';
  scanBtn.disabled = true;
  verdictCard.classList.remove('show');
});

// ── Run scan ─────────────────────────────────────────────────────
scanBtn.addEventListener('click', async () => {
  if (!selectedFile) return;
  scanBtn.disabled = true;
  scanBtn.textContent = 'Scanning…';

  const formData = new FormData();
  formData.append('file', selectedFile);
  formData.append('sample_rate', document.getElementById('rateSelect').value);

  try {
    const res = await fetch('/api/analyze', { method: 'POST', body: formData });
    const data = await res.json();
    if (data.error) {
      alert(data.error);
    } else {
      renderVerdict(data);
    }
  } catch (err) {
    alert('Something went wrong while analyzing the file.');
    console.error(err);
  } finally {
    scanBtn.disabled = false;
    scanBtn.textContent = 'Start Scan';
  }
});

function renderVerdict(data) {
  const isFake = data.verdict === 'FAKE';
  const accent = isFake ? 'var(--red)' : 'var(--green)';

  document.getElementById('verdictIcon').textContent = isFake ? '⚠' : '✓';
  document.getElementById('verdictIcon').style.background = isFake ? 'rgba(244,63,94,0.14)' : 'rgba(52,211,153,0.14)';
  document.getElementById('verdictIcon').style.color = accent;

  document.getElementById('verdictLabel').textContent = data.verdict;
  document.getElementById('verdictLabel').style.color = accent;
  document.getElementById('verdictConf').textContent = `${data.confidence}% confidence`;

  document.getElementById('fakeVal').textContent = `${data.fake_pct}%`;
  document.getElementById('realVal').textContent = `${data.real_pct}%`;
  document.getElementById('fakeBar').style.width = `${data.fake_pct}%`;
  document.getElementById('realBar').style.width = `${data.real_pct}%`;

  document.getElementById('metaType').textContent = data.file_type === 'video' ? '🎥 Video' : '🖼️ Image';
  document.getElementById('metaElapsed').textContent = `${data.elapsed}s`;
  document.getElementById('metaFrames').textContent = data.frames;

  verdictCard.classList.add('show');
  verdictCard.scrollIntoView({ behavior: 'smooth', block: 'nearest' });
}

// ── Dashboard ────────────────────────────────────────────────────
async function refreshStats() {
  try {
    const res = await fetch('/api/stats');
    const data = await res.json();

    document.getElementById('statTotal').textContent = data.total_scans;
    document.getElementById('statFakes').textContent = data.fakes_detected;
    document.getElementById('statReal').textContent = data.authentic;
    document.getElementById('statAcc').textContent = `${data.model_accuracy}%`;

    document.getElementById('legendReal').textContent = data.authentic;
    document.getElementById('legendFake').textContent = data.fakes_detected;
    document.getElementById('donutPct').textContent = `${data.fake_rate}%`;

    const circumference = 2 * Math.PI * 70; // ~440
    const fakeLen = (data.fake_rate / 100) * circumference;
    document.getElementById('donutFake').setAttribute('stroke-dasharray', `${fakeLen} ${circumference}`);

    const list = document.getElementById('historyList');
    if (!data.history.length) {
      list.innerHTML = '<div class="empty-state">No scans yet — run a detection to see results here.</div>';
    } else {
      list.innerHTML = data.history.map(h => `
        <div class="history-row">
          <span class="name">${h.name}</span>
          <span class="badge ${h.verdict.toLowerCase()}">${h.verdict} · ${h.confidence}%</span>
        </div>
      `).join('');
    }
  } catch (err) {
    console.error('Failed to load stats', err);
  }
}