// DNSSEC Check - Background Service Worker
// Uses Google DNS-over-HTTPS API to check DNSSEC (AD flag)

const dnssecCache = new Map();
const CACHE_TTL = 5 * 60 * 1000; // 5 minutes

// --- Icon Generation (OffscreenCanvas) ---

function drawShield(ctx, size, fillColor) {
  const p = size * 0.08; // padding
  const w = size - p * 2;
  const h = size - p * 2;
  const cx = size / 2;
  const top = p;

  ctx.beginPath();
  ctx.moveTo(cx, top);
  ctx.lineTo(p + w, top + h * 0.22);
  ctx.lineTo(p + w, top + h * 0.55);
  ctx.quadraticCurveTo(p + w * 0.95, top + h * 0.82, cx, top + h);
  ctx.quadraticCurveTo(p + w * 0.05, top + h * 0.82, p, top + h * 0.55);
  ctx.lineTo(p, top + h * 0.22);
  ctx.closePath();

  ctx.fillStyle = fillColor;
  ctx.fill();

  // Subtle border
  ctx.strokeStyle = 'rgba(0,0,0,0.15)';
  ctx.lineWidth = Math.max(1, size * 0.03);
  ctx.stroke();
}

function drawCheck(ctx, size) {
  const cx = size / 2;
  const cy = size * 0.52;
  const s = size * 0.18;

  ctx.beginPath();
  ctx.moveTo(cx - s, cy);
  ctx.lineTo(cx - s * 0.25, cy + s * 0.7);
  ctx.lineTo(cx + s, cy - s * 0.6);
  ctx.strokeStyle = '#fff';
  ctx.lineWidth = Math.max(2, size * 0.1);
  ctx.lineCap = 'round';
  ctx.lineJoin = 'round';
  ctx.stroke();
}

function drawX(ctx, size) {
  const cx = size / 2;
  const cy = size * 0.5;
  const s = size * 0.14;

  ctx.strokeStyle = '#fff';
  ctx.lineWidth = Math.max(2, size * 0.1);
  ctx.lineCap = 'round';

  ctx.beginPath();
  ctx.moveTo(cx - s, cy - s);
  ctx.lineTo(cx + s, cy + s);
  ctx.stroke();

  ctx.beginPath();
  ctx.moveTo(cx + s, cy - s);
  ctx.lineTo(cx - s, cy + s);
  ctx.stroke();
}

function drawQuestion(ctx, size) {
  ctx.fillStyle = '#fff';
  ctx.font = `bold ${size * 0.4}px sans-serif`;
  ctx.textAlign = 'center';
  ctx.textBaseline = 'middle';
  ctx.fillText('?', size / 2, size * 0.52);
}

function createIcon(color, symbol, size) {
  const canvas = new OffscreenCanvas(size, size);
  const ctx = canvas.getContext('2d');

  drawShield(ctx, size, color);

  if (symbol === 'check') drawCheck(ctx, size);
  else if (symbol === 'x') drawX(ctx, size);
  else if (symbol === '?') drawQuestion(ctx, size);

  return ctx.getImageData(0, 0, size, size);
}

// Pre-generate all icon states
const STATES = {
  green: { color: '#27ae60', symbol: 'check' },
  red:   { color: '#e74c3c', symbol: 'x' },
  gray:  { color: '#95a5a6', symbol: '?' }
};

const SIZES = [16, 32, 48, 128];
const icons = {};

for (const [name, { color, symbol }] of Object.entries(STATES)) {
  icons[name] = {};
  for (const size of SIZES) {
    icons[name][size] = createIcon(color, symbol, size);
  }
}

function setIcon(tabId, state) {
  chrome.action.setIcon({
    tabId,
    imageData: {
      16:  icons[state][16],
      32:  icons[state][32],
      48:  icons[state][48],
      128: icons[state][128]
    }
  });
}

function setTitle(tabId, text) {
  chrome.action.setTitle({ tabId, title: text });
}

// --- DNSSEC Check ---

async function checkDNSSEC(domain) {
  const cached = dnssecCache.get(domain);
  if (cached && Date.now() - cached.timestamp < CACHE_TTL) {
    return cached;
  }

  try {
    const url = `https://dns.google/resolve?name=${encodeURIComponent(domain)}&type=A&do=1`;
    const response = await fetch(url);

    if (!response.ok) {
      throw new Error(`DNS API returned ${response.status}`);
    }

    const data = await response.json();

    const result = {
      domain,
      dnssec: data.AD === true,
      status: data.Status,
      timestamp: Date.now(),
      error: null
    };

    dnssecCache.set(domain, result);

    // Auto-clean cache entry after TTL
    setTimeout(() => {
      const entry = dnssecCache.get(domain);
      if (entry && Date.now() - entry.timestamp >= CACHE_TTL) {
        dnssecCache.delete(domain);
      }
    }, CACHE_TTL + 1000);

    return result;
  } catch (error) {
    const result = {
      domain,
      dnssec: false,
      status: -1,
      timestamp: Date.now(),
      error: error.message
    };
    return result;
  }
}

// --- Tab Handling ---

function extractDomain(url) {
  try {
    const parsed = new URL(url);
    if (parsed.protocol === 'http:' || parsed.protocol === 'https:') {
      return parsed.hostname;
    }
  } catch {}
  return null;
}

async function checkTab(tabId, url) {
  const domain = extractDomain(url);

  if (!domain) {
    setIcon(tabId, 'gray');
    setTitle(tabId, 'DNSSEC Check - Geen webpagina');
    chrome.storage.session.set({ [String(tabId)]: null });
    return;
  }

  setIcon(tabId, 'gray');
  setTitle(tabId, `DNSSEC Check - Controleren: ${domain}...`);

  const result = await checkDNSSEC(domain);

  if (result.error) {
    setIcon(tabId, 'gray');
    setTitle(tabId, `DNSSEC Check - Fout bij controleren`);
  } else if (result.dnssec) {
    setIcon(tabId, 'green');
    setTitle(tabId, `DNSSEC Check - ${domain} is DNSSEC beveiligd`);
  } else {
    setIcon(tabId, 'red');
    setTitle(tabId, `DNSSEC Check - ${domain} heeft geen DNSSEC`);
  }

  chrome.storage.session.set({ [String(tabId)]: result });
}

// Check on page load
chrome.tabs.onUpdated.addListener((tabId, changeInfo, tab) => {
  if (changeInfo.status === 'complete' && tab.url) {
    checkTab(tabId, tab.url);
  }
});

// Check on tab switch
chrome.tabs.onActivated.addListener(async ({ tabId }) => {
  try {
    const tab = await chrome.tabs.get(tabId);
    if (tab.url) {
      checkTab(tabId, tab.url);
    }
  } catch {}
});

// Clean up on tab close
chrome.tabs.onRemoved.addListener((tabId) => {
  chrome.storage.session.remove(String(tabId));
});

// Message handler for popup
chrome.runtime.onMessage.addListener((message, sender, sendResponse) => {
  if (message.type === 'getStatus') {
    chrome.storage.session.get([String(message.tabId)], (data) => {
      sendResponse(data[String(message.tabId)] || null);
    });
    return true;
  }

  if (message.type === 'recheck') {
    chrome.tabs.get(message.tabId, (tab) => {
      if (tab && tab.url) {
        const domain = extractDomain(tab.url);
        if (domain) dnssecCache.delete(domain);
        checkTab(message.tabId, tab.url);
        setTimeout(() => {
          chrome.storage.session.get([String(message.tabId)], (data) => {
            sendResponse(data[String(message.tabId)] || null);
          });
        }, 1500);
      } else {
        sendResponse(null);
      }
    });
    return true;
  }
});