let db = null;

// ── Persistence ──────────────────────────────────────────────────────────────

function saveToStorage() {
  try {
    const data = db.export(); // Uint8Array
    let binary = '';
    const chunk = 8192;
    for (let i = 0; i < data.length; i += chunk) {
      binary += String.fromCharCode(...data.subarray(i, i + chunk));
    }
    localStorage.setItem(STORAGE_KEY, btoa(binary));
  } catch (e) {
    console.warn('catalyst: failed to persist database', e);
  }
}

function loadFromStorage() {
  try {
    const stored = localStorage.getItem(STORAGE_KEY);
    if (!stored) return null;
    const binary = atob(stored);
    const buf = new Uint8Array(binary.length);
    for (let i = 0; i < binary.length; i++) buf[i] = binary.charCodeAt(i);
    return buf;
  } catch (e) {
    console.warn('catalyst: failed to load database from storage', e);
    return null;
  }
}

// ── Init ─────────────────────────────────────────────────────────────────────

async function initDB() {
  const SQL = await initSqlJs({ locateFile: f => SQL_JS_CDN + f });

  const saved = loadFromStorage();
  if (saved) {
    db = new SQL.Database(saved);
    return;
  }

  db = new SQL.Database();
  db.run(`
    CREATE TABLE instances (
      id                   INTEGER PRIMARY KEY AUTOINCREMENT,
      name                 TEXT    NOT NULL,
      state                TEXT    DEFAULT 'deployed',
      stack                TEXT    DEFAULT '',
      vmid                 INTEGER UNIQUE NOT NULL,
      atlas                INTEGER DEFAULT 0,
      argus                INTEGER DEFAULT 0,
      semaphore            INTEGER DEFAULT 0,
      patchmon             INTEGER DEFAULT 0,
      tailscale            INTEGER DEFAULT 0,
      andromeda            INTEGER DEFAULT 0,
      tailscale_ip         TEXT    DEFAULT '',
      hardware_acceleration INTEGER DEFAULT 0,
      createdAt            TEXT    DEFAULT (datetime('now')),
      updatedAt            TEXT    DEFAULT (datetime('now'))
    )
  `);

  const stmt = db.prepare(`
    INSERT INTO instances
      (name, state, stack, vmid, atlas, argus, semaphore, patchmon, tailscale, andromeda, tailscale_ip, hardware_acceleration)
    VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
  `);

  SEED.forEach(s => stmt.run([
    s.name, s.state, s.stack, s.vmid,
    +s.atlas, +s.argus, +s.semaphore, +s.patchmon,
    +s.tailscale, +s.andromeda, s.tailscale_ip, +s.hardware_acceleration,
  ]));

  stmt.free();
  saveToStorage();
}

// ── Queries ──────────────────────────────────────────────────────────────────

function getInstances(filters = {}) {
  let sql = 'SELECT * FROM instances WHERE 1=1';
  const params = [];

  if (filters.search) {
    sql += ' AND (name LIKE ? OR CAST(vmid AS TEXT) LIKE ? OR stack LIKE ?)';
    const s = `%${filters.search}%`;
    params.push(s, s, s);
  }
  if (filters.state) { sql += ' AND state = ?'; params.push(filters.state); }
  if (filters.stack) { sql += ' AND stack = ?'; params.push(filters.stack); }

  sql += ' ORDER BY name ASC';

  const res = db.exec(sql, params);
  if (!res.length) return [];
  const cols = res[0].columns;
  return res[0].values.map(row => Object.fromEntries(cols.map((c, i) => [c, row[i]])));
}

function getInstance(vmid) {
  const res = db.exec('SELECT * FROM instances WHERE vmid = ?', [vmid]);
  if (!res.length) return null;
  const cols = res[0].columns;
  return Object.fromEntries(cols.map((c, i) => [c, res[0].values[0][i]]));
}

function getDistinctStacks() {
  const res = db.exec(`SELECT DISTINCT stack FROM instances WHERE stack != '' ORDER BY stack`);
  if (!res.length) return [];
  return res[0].values.map(row => row[0]);
}

// ── Mutations ─────────────────────────────────────────────────────────────────

function createInstance(data) {
  try {
    db.run(
      `INSERT INTO instances
        (name, state, stack, vmid, atlas, argus, semaphore, patchmon, tailscale, andromeda, tailscale_ip, hardware_acceleration)
       VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)`,
      [data.name, data.state, data.stack, data.vmid,
       data.atlas, data.argus, data.semaphore, data.patchmon,
       data.tailscale, data.andromeda, data.tailscale_ip, data.hardware_acceleration]
    );
    saveToStorage();
    return { ok: true };
  } catch (e) {
    return { ok: false, error: e.message };
  }
}

function updateInstance(id, data) {
  try {
    db.run(
      `UPDATE instances SET
        name=?, state=?, stack=?, vmid=?,
        atlas=?, argus=?, semaphore=?, patchmon=?,
        tailscale=?, andromeda=?, tailscale_ip=?, hardware_acceleration=?,
        updatedAt=datetime('now')
       WHERE id=?`,
      [data.name, data.state, data.stack, data.vmid,
       data.atlas, data.argus, data.semaphore, data.patchmon,
       data.tailscale, data.andromeda, data.tailscale_ip, data.hardware_acceleration,
       id]
    );
    saveToStorage();
    return { ok: true };
  } catch (e) {
    return { ok: false, error: e.message };
  }
}

function deleteInstance(id) {
  db.run('DELETE FROM instances WHERE id = ?', [id]);
  saveToStorage();
}