// ── ws.js — WebSocket connection and subscription ────────

let ws = null;
let wsStatus = 'disconnected';
let wsReconnectTimeout = null;
let wsReconnectDelay = 1000;
const wsCallbacks = new Set();

export function getWsURL() {
  const protocol = window.location.protocol === 'https:' ? 'wss:' : 'ws:';
  return protocol + '//' + window.location.host + '/api/v1/ws';
}

export function connectWS() {
  if (ws && (ws.readyState === WebSocket.OPEN || ws.readyState === WebSocket.CONNECTING)) {
    return;
  }

  try {
    ws = new WebSocket(getWsURL());

    ws.onopen = () => {
      console.log('WebSocket connected');
      wsStatus = 'connected';
      wsReconnectDelay = 1000;
      updateWSIndicator();
      wsCallbacks.forEach(cb => cb({ type: 'connected' }));
    };

    ws.onmessage = (event) => {
      try {
        const data = JSON.parse(event.data);
        wsCallbacks.forEach(cb => cb({ type: 'message', data }));
      } catch (e) {
        console.error('Failed to parse WS message:', e);
      }
    };

    ws.onclose = () => {
      console.log('WebSocket disconnected');
      wsStatus = 'reconnecting';
      updateWSIndicator();
      wsCallbacks.forEach(cb => cb({ type: 'disconnected' }));
      wsReconnectTimeout = setTimeout(connectWS, wsReconnectDelay);
      wsReconnectDelay = Math.min(wsReconnectDelay * 1.5, 30000);
    };

    ws.onerror = (err) => {
      console.error('WebSocket error:', err);
    };
  } catch (e) {
    console.error('Failed to connect WebSocket:', e);
    wsReconnectTimeout = setTimeout(connectWS, wsReconnectDelay);
    wsReconnectDelay = Math.min(wsReconnectDelay * 1.5, 30000);
  }
}

export function subscribeWS(callback) {
  wsCallbacks.add(callback);
  if (!ws || ws.readyState !== WebSocket.OPEN) {
    connectWS();
  }
  return () => wsCallbacks.delete(callback);
}

export function updateWSIndicator() {
  const dot = document.getElementById('ws-dot');
  if (!dot) return;
  dot.className = 'ws-dot ' + wsStatus;
  const labels = {
    connected: 'Live — WebSocket connected',
    reconnecting: 'Reconnecting…',
    disconnected: 'Disconnected',
  };
  dot.title = labels[wsStatus] || 'Unknown';
}