'use strict';

const Term = (() => {
  let term = null;
  let fitAddon = null;
  let ws = null;
  let panel = null;
  let wantOpen = false;
  let retryTimer = null;
  let retryMs = 400;

  function ensure() {
    if (term) return;
    panel = document.getElementById('terminal-panel');
    term = new Terminal({ cursorBlink: true, scrollback: 2000, cols: 80, rows: 24 });
    fitAddon = new FitAddon.FitAddon();
    term.loadAddon(fitAddon);
    term.open(document.getElementById('terminal'));
    try { fitAddon.fit(); } catch (e) {}
    term.onData((d) => {
      if (ws && ws.readyState === WebSocket.OPEN) {
        try { ws.send(d); } catch (e) {}
      }
    });
  }

  function scheduleReconnect() {
    if (!wantOpen) return;
    clearTimeout(retryTimer);
    retryTimer = setTimeout(() => {
      if (wantOpen) connect();
    }, retryMs);
    retryMs = Math.min(5000, Math.max(400, retryMs * 2));
  }

  function toggle() {
    ensure();
    if (panel.classList.contains('hidden')) {
      panel.classList.remove('hidden');
      document.getElementById('terminal-btn').classList.add('active');
      try { fitAddon.fit(); } catch (e) {}
      wantOpen = true;
      retryMs = 400;
      connect();
    } else {
      panel.classList.add('hidden');
      document.getElementById('terminal-btn').classList.remove('active');
      disconnect();
    }
  }

  function connect() {
    if (!wantOpen) return;
    if (ws && (ws.readyState === WebSocket.OPEN || ws.readyState === WebSocket.CONNECTING)) return;
    if (term) term.reset();
    let sock;
    try {
      sock = new WebSocket(App.terminalWs);
    } catch (e) {
      term.writeln('\r\n[cannot reach daemon terminal: ' + e.message + ']');
      scheduleReconnect();
      return;
    }
    ws = sock;
    sock.onopen = () => { retryMs = 400; };
    sock.onmessage = (ev) => {
      if (typeof ev.data === 'string') term.write(ev.data);
      else ev.data.text().then((t) => term.write(t));
    };
    sock.onclose = () => {
      if (ws === sock) ws = null;
      if (term && wantOpen) {
        term.writeln('\r\n[connection closed — reconnecting]');
        scheduleReconnect();
      } else if (term) {
        term.writeln('\r\n[connection closed]');
      }
    };
    sock.onerror = () => { try { sock.close(); } catch (e) {} };
  }

  function disconnect() {
    wantOpen = false;
    clearTimeout(retryTimer);
    retryTimer = null;
    if (ws) { try { ws.close(); } catch (e) {} ws = null; }
  }

  function isOpen() {
    return !!panel && !panel.classList.contains('hidden');
  }

  function close() {
    if (isOpen()) toggle();
  }

  window.addEventListener('resize', () => {
    if (fitAddon && panel && !panel.classList.contains('hidden')) {
      try { fitAddon.fit(); } catch (e) {}
    }
  });

  return { toggle, close, isOpen };
})();