/**
 * SSH Connections page — connection grid, add/edit modal, and full in-browser SSH terminal.
 * Session lifecycle: start Holesail tunnel → open WebSocket → spawn SSH via PTY on native host
 * → bridge PTY ↔ WebSocket ↔ xterm.js in the browser.
 * Handles auto-reconnect with exponential backoff and PTY resize via ResizeObserver.
 * Depends on: core/utils.js ($, escapeHtml, log), core/messaging.js (sendToNative),
 *             ui/toast.js (showToast, copyToClipboard), ui/modal.js (openModal, closeModal, showModalError)
 */

let sshConnections = [];
let activeSshSession = null; // { sessionId, wsPort, term, fitAddon, ws, resizeObserver, conn, dataDisposable }
let _sshReconnectTimer = null;
let _sshConnecting = false;
const SSH_RECONNECT_BASE_MS = 3000;
const SSH_RECONNECT_MAX_MS = 60000;

function generateSshId() {
  return 'ssh-' + Date.now().toString(36) + '-' + Math.random().toString(36).slice(2, 7);
}

function loadSshConnections(cb) {
  chrome.runtime.sendMessage(
    { target: 'holesail-native', action: 'send', payload: { type: 'getSshConnections' } },
    (response) => {
      if (response && response.ok && Array.isArray(response.sshConnections)) {
        sshConnections = response.sshConnections.map(c => {
          let password = '';
          if (c.passwordB64) {
            try { password = decodeURIComponent(escape(atob(c.passwordB64))); } catch (_) {}
          }
          return { ...c, password };
        });
      }
      if (cb) cb(sshConnections);
    }
  );
}

function saveSshConnections(cb) {
  const toSave = sshConnections.map(c => {
    const { password, ...rest } = c; // eslint-disable-line no-unused-vars
    if (password) rest.passwordB64 = btoa(unescape(encodeURIComponent(password)));
    else delete rest.passwordB64;
    return rest;
  });
  chrome.runtime.sendMessage(
    { target: 'holesail-native', action: 'send', payload: { type: 'setSshConnections', payload: { connections: toSave } } },
    (response) => {
      if (response && !response.ok) {
        log('saveSshConnections failed:', response.error);
      }
      renderSshGrid();
      const countEl = $('sshCount');
      if (countEl) countEl.textContent = sshConnections.length;
      if (cb) cb();
    }
  );
}

/**
 * Re-render the SSH connection grid from the current `sshConnections` array.
 */
function renderSshGrid() {
  const grid = $('sshGrid');
  if (!grid) return;
  if (sshConnections.length === 0) {
    grid.innerHTML = `
      <div class="empty-state" style="grid-column:1/-1">
        <svg viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="1.5"><rect x="2" y="4" width="20" height="16" rx="2"/><polyline points="8,10 12,14 16,10"/></svg>
        <div class="empty-state-title">No SSH connections</div>
        <div class="empty-state-desc">Add a connection to get started. You'll need an hs:// key for the remote peer.</div>
      </div>`;
    return;
  }
  grid.innerHTML = sshConnections.map(conn => `
    <div class="ssh-conn-card" data-ssh-id="${escapeHtml(conn.id)}">
      <div class="ssh-conn-card-top">
        <div class="ssh-conn-icon">
          <svg viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2">
            <rect x="2" y="4" width="20" height="16" rx="2"/>
            <polyline points="8,10 12,14 16,10"/>
          </svg>
        </div>
        <div class="ssh-conn-info">
          <div class="ssh-conn-label">${escapeHtml(conn.label || conn.username + '@ssh')}</div>
          ${conn.autoReconnect ? '<div style="font-size:10.5px;color:var(--cyan);margin-top:2px;">Auto-reconnect enabled</div>' : ''}
        </div>
        <div class="ssh-conn-actions">
          <button class="btn btn-primary" data-ssh-connect="${escapeHtml(conn.id)}" style="padding:6px 14px;font-size:12px;">
            <svg viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" style="width:13px;height:13px;"><polyline points="5,12 19,12"/><polyline points="12,5 19,12 12,19"/></svg>
            Connect
          </button>
          <button class="btn btn-ghost" data-ssh-edit="${escapeHtml(conn.id)}" style="padding:6px 10px;" title="Edit">
            <svg viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" style="width:14px;height:14px;"><path d="M11 4H4a2 2 0 0 0-2 2v14a2 2 0 0 0 2 2h14a2 2 0 0 0 2-2v-7"/><path d="M18.5 2.5a2.121 2.121 0 0 1 3 3L12 15l-4 1 1-4 9.5-9.5z"/></svg>
          </button>
          <button class="btn btn-ghost" data-ssh-remove="${escapeHtml(conn.id)}" style="padding:6px 10px;color:var(--red);" title="Remove">
            <svg viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" style="width:14px;height:14px;"><polyline points="3,6 5,6 21,6"/><path d="M19,6l-1,14a2,2,0,0,1-2,2H8a2,2,0,0,1-2-2L5,6"/></svg>
          </button>
        </div>
      </div>
    </div>`).join('');

  grid.querySelectorAll('[data-ssh-connect]').forEach(btn => {
    btn.addEventListener('click', (e) => {
      e.stopPropagation();
      const conn = sshConnections.find(c => c.id === btn.dataset.sshConnect);
      if (conn) connectSsh(conn);
    });
  });
  grid.querySelectorAll('[data-ssh-edit]').forEach(btn => {
    btn.addEventListener('click', (e) => {
      e.stopPropagation();
      const conn = sshConnections.find(c => c.id === btn.dataset.sshEdit);
      if (conn) openAddSshModal(conn);
    });
  });
  grid.querySelectorAll('[data-ssh-remove]').forEach(btn => {
    btn.addEventListener('click', (e) => {
      e.stopPropagation();
      const conn = sshConnections.find(c => c.id === btn.dataset.sshRemove);
      if (conn) {
        $('removeSshName').textContent = conn.label || conn.username;
        $('removeSshConfirm').dataset.sshId = conn.id;
        openModal('modal-removeSsh');
      }
    });
  });
}

/**
 * Open the Add/Edit SSH Connection modal, pre-populated with `conn` if provided.
 * @param {object} [conn] - Existing connection to edit; omit to add a new one.
 */
function openAddSshModal(conn) {
  const isEdit = !!conn;
  $('modal-addSsh-title').textContent = isEdit ? 'Edit SSH Connection' : 'Add SSH Connection';
  $('sshConnLabel').value = conn ? conn.label : '';
  $('sshConnHsUrl').value = conn ? conn.hsUrl : '';
  $('sshConnUsername').value = conn ? conn.username : '';
  $('sshConnPassword').value = conn ? (conn.password || '') : '';
  const arEl = $('sshConnAutoReconnect');
  if (arEl) arEl.checked = conn ? !!conn.autoReconnect : false;
  $('sshConnEditId').value = conn ? conn.id : '';
  $('sshConnSubmit').textContent = isEdit ? 'Save Changes' : 'Save Connection';
  openModal('modal-addSsh');
}

function updateTermSizeDisplay(term) {
  const el = $('termSizeDisplay');
  if (el && term) el.textContent = term.cols + '×' + term.rows;
}

/**
 * Open the SSH terminal modal and start a new SSH session for the given connection.
 * Guards against concurrent calls with `_sshConnecting`. Disconnects any existing session first.
 * @param {object} conn - SSH connection object with `hsUrl`, `username`, `password`, etc.
 * @returns {Promise<void>}
 */
function _getXtermTheme() {
  const isLight = document.documentElement.getAttribute('data-theme') === 'light';
  if (isLight) {
    return {
      background: '#1a1a1e',
      foreground: '#e4e4e7',
      cursor: '#0891b2',
      cursorAccent: '#1a1a1e',
      selectionBackground: 'rgba(8,145,178,0.30)',
      black: '#18181b',
      red: '#e11d48',
      green: '#16a34a',
      yellow: '#d97706',
      blue: '#2563eb',
      magenta: '#9333ea',
      cyan: '#0891b2',
      white: '#e4e4e7',
      brightBlack: '#3f3f46',
      brightRed: '#fb7185',
      brightGreen: '#86efac',
      brightYellow: '#fde68a',
      brightBlue: '#93c5fd',
      brightMagenta: '#d8b4fe',
      brightCyan: '#67e8f9',
      brightWhite: '#fafafa',
    };
  }
  return {
    background: '#0d0d0f',
    foreground: '#e4e4e7',
    cursor: '#22d3ee',
    cursorAccent: '#0d0d0f',
    selectionBackground: 'rgba(34,211,238,0.25)',
    black: '#18181b',
    red: '#f43f5e',
    green: '#4ade80',
    yellow: '#fbbf24',
    blue: '#60a5fa',
    magenta: '#c084fc',
    cyan: '#22d3ee',
    white: '#e4e4e7',
    brightBlack: '#3f3f46',
    brightRed: '#fb7185',
    brightGreen: '#86efac',
    brightYellow: '#fde68a',
    brightBlue: '#93c5fd',
    brightMagenta: '#d8b4fe',
    brightCyan: '#67e8f9',
    brightWhite: '#fafafa',
  };
}

async function connectSsh(conn) {
  if (_sshConnecting) return;
  _sshConnecting = true;
  if (_sshReconnectTimer) { clearTimeout(_sshReconnectTimer); _sshReconnectTimer = null; }
  try {
    return await _connectSshImpl(conn);
  } finally {
    _sshConnecting = false;
  }
}

async function _connectSshImpl(conn) {
  openModal('modal-sshTerminal');
  $('termConnLabel').textContent = conn.label || conn.username;
  $('termUserHost').textContent = conn.username + '@ssh';
  $('termStatusDot').className = 'terminal-status-dot';
  $('termStateDisplay').textContent = 'Connecting…';
  $('termStateDisplay').style.color = 'var(--amber)';

  await disconnectSsh();

  const term = new Terminal({
    fontFamily: "'JetBrains Mono', 'Fira Code', 'Cascadia Code', monospace",
    fontSize: 13,
    lineHeight: 1.3,
    cursorBlink: true,
    cursorStyle: 'block',
    scrollback: 5000,
    theme: _getXtermTheme()
  });

  const fitAddon = new FitAddon.FitAddon();
  term.loadAddon(fitAddon);

  const container = $('terminalContainer');
  container.innerHTML = '';
  term.open(container);

  // Fit synchronously now that the container is in the DOM, then wait a frame
  // for the browser to finish layout so dimensions are accurate before we
  // send cols/rows to the native host.
  await new Promise(resolve => requestAnimationFrame(() => {
    try { fitAddon.fit(); } catch (_) {}
    updateTermSizeDisplay(term);
    resolve();
  }));

  term.writeln('\x1b[36mConnecting to ' + escapeHtml(conn.label || conn.username) + '…\x1b[0m');
  term.writeln('\x1b[90mEstablishing Holesail tunnel…\x1b[0m');

  const cols = term.cols || 80;
  const rows = term.rows || 24;
  const result = await sendToNative('startSshSession', {
    hsUrl: conn.hsUrl,
    username: conn.username,
    password: conn.password || '',
    cols,
    rows,
    label: conn.label || conn.username
  });

  if (!result || !result.ok) {
    const errMsg = (result && result.error) || 'Unknown error';
    term.writeln('\x1b[31mFailed to start session: ' + errMsg + '\x1b[0m');
    $('termStatusDot').className = 'terminal-status-dot disconnected';
    $('termStateDisplay').textContent = 'Error';
    $('termStateDisplay').style.color = 'var(--red)';
    activeSshSession = { term, fitAddon, ws: null, resizeObserver: null, conn, sessionId: null };
    return;
  }

  const { sessionId, wsPort } = result;
  term.writeln('\x1b[90mTunnel ready — connecting SSH…\x1b[0m');

  let ws;
  try {
    ws = new WebSocket('ws://127.0.0.1:' + wsPort);
    ws.binaryType = 'arraybuffer';
  } catch (e) {
    term.writeln('\x1b[31mWebSocket connection failed: ' + e.message + '\x1b[0m');
    sendToNative('stopSshSession', { sessionId });
    return;
  }

  ws.onopen = () => {
    $('termStatusDot').className = 'terminal-status-dot';
    $('termStateDisplay').textContent = 'Connected';
    $('termStateDisplay').style.color = 'var(--green)';
    // Send a ready-signal so the native host knows the browser WebSocket is
    // fully open and can safely flush buffered PTY output (MOTD, prompt).
    ws.send('\x00');
    term.focus();
  };

  let firstMessage = true;
  ws.onmessage = (event) => {
    const data = event.data instanceof ArrayBuffer
      ? new Uint8Array(event.data)
      : event.data;
    if (firstMessage) {
      firstMessage = false;
      // Prepend ESC[2J (clear screen) + ESC[H (cursor home) to the first SSH
      // data chunk so the clear and the MOTD are written atomically in the
      // same xterm.js render pass — avoids the race where term.clear() wipes
      // data that was already queued by term.write().
      const CLEAR_HOME = '\x1b[2J\x1b[H';
      if (typeof data === 'string') {
        term.write(CLEAR_HOME + data);
      } else {
        const prefix = new TextEncoder().encode(CLEAR_HOME);
        const combined = new Uint8Array(prefix.length + data.length);
        combined.set(prefix);
        combined.set(data, prefix.length);
        term.write(combined);
      }
      return;
    }
    term.write(data);
  };

  let _reconnectDelay = SSH_RECONNECT_BASE_MS;
  ws.onclose = () => {
    $('termStatusDot').className = 'terminal-status-dot disconnected';
    $('termStateDisplay').textContent = 'Disconnected';
    $('termStateDisplay').style.color = 'var(--text3)';
    term.writeln('\r\n\x1b[90m[Session closed]\x1b[0m');
    if (conn.autoReconnect && activeSshSession) {
      const delay = _reconnectDelay;
      _reconnectDelay = Math.min(_reconnectDelay * 2, SSH_RECONNECT_MAX_MS);
      term.writeln('\x1b[33mAuto-reconnect in ' + Math.round(delay / 1000) + 's…\x1b[0m');
      $('termStateDisplay').textContent = 'Reconnecting…';
      $('termStateDisplay').style.color = 'var(--amber)';
      if (_sshReconnectTimer) clearTimeout(_sshReconnectTimer);
      _sshReconnectTimer = setTimeout(() => {
        _sshReconnectTimer = null;
        if (activeSshSession && conn.autoReconnect) connectSsh(conn);
      }, delay);
    }
  };

  ws.onerror = () => {
    term.writeln('\r\n\x1b[31m[WebSocket error]\x1b[0m');
  };

  const dataDisposable = term.onData((data) => {
    if (ws && ws.readyState === WebSocket.OPEN) {
      ws.send(data);
    }
  });

  // Resize observer — refit on container resize, debounced so we don't
  // flood the native host with stty commands during a window drag.
  activeSshSession = { sessionId, wsPort, term, fitAddon, ws, resizeObserver: null, resizeTimer: null, conn, dataDisposable };
  const resizeObserver = new ResizeObserver(() => {
    try { fitAddon.fit(); updateTermSizeDisplay(term); } catch (_) {}
    if (activeSshSession) clearTimeout(activeSshSession.resizeTimer);
    if (activeSshSession) {
      activeSshSession.resizeTimer = setTimeout(() => {
        if (activeSshSession) activeSshSession.resizeTimer = null;
        try {
          sendToNative('resizeSshSession', { sessionId, cols: term.cols, rows: term.rows });
        } catch (_) {}
      }, 150);
    }
  });
  resizeObserver.observe(container);
  activeSshSession.resizeObserver = resizeObserver;
}

/**
 * Disconnect the active SSH session: close the WebSocket, dispose the xterm terminal,
 * disconnect the ResizeObserver, and send a stopSshSession message to the native host.
 * @returns {Promise<void>}
 */
async function disconnectSsh() {
  if (!activeSshSession) return;
  const { sessionId, ws, term, fitAddon, resizeObserver, resizeTimer, dataDisposable } = activeSshSession;
  activeSshSession = null;
  if (_sshReconnectTimer) { clearTimeout(_sshReconnectTimer); _sshReconnectTimer = null; }

  if (resizeTimer) clearTimeout(resizeTimer);
  if (resizeObserver) resizeObserver.disconnect();
  if (dataDisposable) dataDisposable.dispose();
  if (ws) { try { ws.close(); } catch (_) {} }
  if (term) { try { term.dispose(); } catch (_) {} }
  if (sessionId) {
    await sendToNative('stopSshSession', { sessionId });
  }
}

/**
 * Attach all event listeners for the SSH Connections page.
 * Called once during dashboard initialisation.
 */
function setupSshEvents() {
  $('addSshBtn')?.addEventListener('click', () => openAddSshModal(null));

  $('sshConnSubmit')?.addEventListener('click', () => {
    const label = $('sshConnLabel').value.trim();
    const hsUrl = $('sshConnHsUrl').value.trim();
    const username = $('sshConnUsername').value.trim();
    const password = $('sshConnPassword').value;
    const editId = $('sshConnEditId').value;

    if (!hsUrl) { showModalError('modal-addSsh', 'sshConnError', 'Holesail key is required'); return; }
    if (!username) { showModalError('modal-addSsh', 'sshConnError', 'Username is required'); return; }
    if (!hsUrl.startsWith('hs://')) { showModalError('modal-addSsh', 'sshConnError', 'Key must start with hs://'); return; }

    const autoReconnect = !!$('sshConnAutoReconnect')?.checked;
    if (editId) {
      const idx = sshConnections.findIndex(c => c.id === editId);
      if (idx !== -1) {
        sshConnections[idx] = { ...sshConnections[idx], label, hsUrl, username, password, autoReconnect };
      }
    } else {
      sshConnections.push({ id: generateSshId(), label, hsUrl, username, password, autoReconnect });
    }
    saveSshConnections();
    closeModal('modal-addSsh');
    showToast(editId ? 'Connection updated' : 'Connection saved', 'success');
  });

  $('removeSshConfirm')?.addEventListener('click', () => {
    const id = $('removeSshConfirm').dataset.sshId;
    sshConnections = sshConnections.filter(c => c.id !== id);
    saveSshConnections();
    closeModal('modal-removeSsh');
    showToast('Connection removed', 'success');
  });

  $('termDisconnectBtn')?.addEventListener('click', async () => {
    await disconnectSsh();
    closeModal('modal-sshTerminal');
  });

  $('termCopyBtn')?.addEventListener('click', () => {
    if (activeSshSession && activeSshSession.term) {
      const sel = activeSshSession.term.getSelection();
      if (sel) copyToClipboard(sel, null);
      else showToast('No text selected', 'default');
    }
  });

  $('termFullscreenBtn')?.addEventListener('click', () => {
    const modal = document.querySelector('#modal-sshTerminal .modal');
    if (!modal) return;
    if (modal.style.width === '100vw') {
      modal.style.width = '';
      modal.style.height = '';
      modal.style.borderRadius = '';
    } else {
      modal.style.width = '100vw';
      modal.style.height = '100vh';
      modal.style.borderRadius = '0';
    }
    setTimeout(() => {
      if (activeSshSession && activeSshSession.fitAddon) {
        activeSshSession.fitAddon.fit();
        updateTermSizeDisplay(activeSshSession.term);
      }
    }, 50);
  });

  const termModal = $('modal-sshTerminal');
  if (termModal) {
    const observer = new MutationObserver(() => {
      if (!termModal.classList.contains('open') && activeSshSession) {
        disconnectSsh();
      }
    });
    observer.observe(termModal, { attributes: true, attributeFilter: ['class'] });
    window.addEventListener('beforeunload', () => observer.disconnect(), { once: true });
  }
}