const form = document.getElementById('uploadForm');
const input = document.getElementById('imageInput');
const preview = document.getElementById('preview');
const dropZone = document.getElementById('dropZone');
const fileName = document.getElementById('fileName');
const button = document.getElementById('analyseButton');
const title = document.getElementById('verdictTitle');
const badge = document.getElementById('verdictBadge');
const note = document.getElementById('reportNote');
const status = document.getElementById('serviceStatus');
const rows = [...document.querySelectorAll('.test-list li')];
let previewUrl = '';

function setServiceState(online) {
  status.textContent = online ? 'Service ready' : 'Service unavailable';
  status.className = `status ${online ? 'online' : 'offline'}`;
}

fetch('/api/health', { cache: 'no-store' })
  .then((response) => setServiceState(response.ok))
  .catch(() => setServiceState(false));

function selectFile(file) {
  if (!file) return;
  if (!['image/jpeg', 'image/png', 'image/webp'].includes(file.type)) {
    showError('Select a JPEG, PNG or WebP image.');
    input.value = '';
    return;
  }
  if (file.size > 8 * 1024 * 1024) {
    showError('The selected image is larger than 8 MB.');
    input.value = '';
    return;
  }
  if (previewUrl) URL.revokeObjectURL(previewUrl);
  previewUrl = URL.createObjectURL(file);
  preview.src = previewUrl;
  fileName.textContent = file.name;
  dropZone.classList.add('has-preview');
  resetReport();
}

input.addEventListener('change', () => selectFile(input.files[0]));

for (const eventName of ['dragenter', 'dragover']) {
  dropZone.addEventListener(eventName, (event) => {
    event.preventDefault();
    dropZone.classList.add('dragging');
  });
}

for (const eventName of ['dragleave', 'drop']) {
  dropZone.addEventListener(eventName, (event) => {
    event.preventDefault();
    dropZone.classList.remove('dragging');
  });
}

dropZone.addEventListener('drop', (event) => {
  const file = event.dataTransfer.files[0];
  if (!file) return;
  const transfer = new DataTransfer();
  transfer.items.add(file);
  input.files = transfer.files;
  selectFile(file);
});

function resetReport() {
  title.textContent = 'Ready to analyse';
  badge.textContent = 'Not tested';
  badge.className = 'verdict neutral';
  note.textContent = 'Tests run in order and stop immediately when one rejects the image.';
  rows.forEach((row) => {
    row.className = '';
    row.querySelector('b').textContent = 'Waiting';
    row.removeAttribute('title');
  });
}

function showRunning() {
  title.textContent = 'Analysis in progress';
  badge.textContent = 'Running';
  badge.className = 'verdict running';
  note.textContent = 'Free Spaces can be slow after waking up. Keep this page open.';
  rows.forEach((row) => {
    row.className = '';
    row.querySelector('b').textContent = 'Waiting';
    row.removeAttribute('title');
  });
}

function showError(message) {
  title.textContent = 'Analysis unavailable';
  badge.textContent = 'Error';
  badge.className = 'verdict error';
  note.textContent = message;
}

function renderReport(report) {
  const labels = { approved: 'Approved', rejected: 'Rejected', error: 'Error' };
  title.textContent = report.verdict === 'approved' ? 'Image passed every test' :
    report.verdict === 'rejected' ? 'Image did not pass moderation' : 'Analysis could not finish';
  badge.textContent = labels[report.verdict] || 'Error';
  badge.className = `verdict ${report.verdict}`;

  rows.forEach((row, index) => {
    const result = report.results[index];
    if (!result) {
      row.className = 'skipped';
      row.querySelector('b').textContent = 'Skipped';
      return;
    }
    row.className = result.status;
    const score = typeof result.score === 'number' ? ` · ${(result.score * 100).toFixed(1)}%` : '';
    row.querySelector('b').textContent = `${result.status === 'passed' ? 'Passed' : result.status === 'rejected' ? 'Failed' : 'Error'}${score}`;
    if (result.detail || result.warning) row.title = [result.detail, result.warning].filter(Boolean).join(' ');
  });

  const failed = report.results.find((result) => !result.passed);
  note.textContent = failed
    ? `${failed.name} stopped the sequence. ${failed.detail || failed.warning || ''}`.trim()
    : 'All four automated tests completed successfully.';
}

function renderProgress(event) {
  title.textContent = 'Analysis in progress';
  badge.textContent = 'Running';
  badge.className = 'verdict running';
  const active = typeof event.active === 'number' ? event.active : -1;
  rows.forEach((row, index) => {
    const result = event.results && event.results[index];
    row.removeAttribute('title');
    if (result) {
      row.className = result.status;
      const score = typeof result.score === 'number' ? ` · ${(result.score * 100).toFixed(1)}%` : '';
      row.querySelector('b').textContent = `${result.status === 'passed' ? 'Passed' : result.status === 'rejected' ? 'Failed' : 'Error'}${score}`;
      if (result.detail || result.warning) row.title = [result.detail, result.warning].filter(Boolean).join(' ');
    } else if (index === active) {
      row.className = 'running';
      row.querySelector('b').textContent = 'Running';
    } else {
      row.className = '';
      row.querySelector('b').textContent = 'Waiting';
    }
  });
  note.textContent = active >= 0
    ? `${event.activeName || rows[active]?.children[1]?.textContent || 'Current test'} is running.`
    : 'Tests run in order and stop immediately when one rejects the image.';
}

async function readProgressStream(response) {
  if (!response.body) {
    const payload = await response.json();
    if (!response.ok) throw new Error(payload.detail || `HTTP error ${response.status}`);
    renderReport(payload);
    return;
  }

  if (!response.ok) {
    let payload = {};
    try { payload = await response.json(); } catch {}
    throw new Error(payload.detail || `HTTP error ${response.status}`);
  }

  const reader = response.body.getReader();
  const decoder = new TextDecoder();
  let buffer = '';

  while (true) {
    const { value, done } = await reader.read();
    if (done) break;
    buffer += decoder.decode(value, { stream: true });
    const lines = buffer.split('\n');
    buffer = lines.pop() || '';
    for (const line of lines) {
      if (!line.trim()) continue;
      const event = JSON.parse(line);
      if (event.type === 'progress') renderProgress(event);
      if (event.type === 'complete') renderReport(event.report);
    }
  }

  if (buffer.trim()) {
    const event = JSON.parse(buffer);
    if (event.type === 'progress') renderProgress(event);
    if (event.type === 'complete') renderReport(event.report);
  }
}

form.addEventListener('submit', async (event) => {
  event.preventDefault();
  const file = input.files[0];
  if (!file) {
    showError('Select an image before running moderation.');
    return;
  }

  showRunning();
  button.disabled = true;
  button.textContent = 'Analysing...';
  const body = new FormData();
  body.append('image', file);

  try {
    const response = await fetch('/api/analyse-stream', { method: 'POST', body });
    await readProgressStream(response);
  } catch (error) {
    showError(error.message || 'The analysis request failed.');
  } finally {
    button.disabled = false;
    button.textContent = 'Run moderation';
  }
});