import { pool } from '../../config/db.js';

const DEVICE_COLS = [
  'hostname', 'kind', 'manufacturer', 'model', 'serial', 'os_name', 'os_version', 'os_arch', 'domain', 'last_user',
  'ip_main', 'mac_main', 'cpu_summary', 'ram_mb', 'disk_total_mb', 'disk_free_mb', 'max_disk_used_pct',
  'agent_version', 'tag', 'itemtype',
];

const CHILD_TABLES = {
  cpus: { table: 'device_cpus', cols: ['name', 'manufacturer', 'cores', 'threads', 'speed_mhz'] },
  memories: { table: 'device_memories', cols: ['slot', 'capacity_mb', 'type', 'speed', 'manufacturer', 'serial'] },
  disks: { table: 'device_disks', cols: ['name', 'model', 'manufacturer', 'type', 'interface', 'size_mb', 'serial'] },
  volumes: { table: 'device_volumes', cols: ['mount', 'label', 'filesystem', 'type', 'total_mb', 'free_mb'] },
  networks: { table: 'device_networks', cols: ['description', 'mac', 'ip', 'mask', 'gateway', 'type', 'status'] },
  monitors: { table: 'device_monitors', cols: ['manufacturer', 'model', 'serial'] },
  accounts: { table: 'device_accounts', cols: ['kind', 'name', 'domain', 'sid'] },
  software: { table: 'device_software', cols: ['name', 'version', 'publisher', 'install_date', 'category', 'is_component'] },
};

// ---------- Tokens de ingesta ----------

export async function findActiveTokenByHash(hash) {
  const [rows] = await pool.query('SELECT id FROM inventory_tokens WHERE token_hash = ? AND is_active = 1', [hash]);
  return rows[0] || null;
}

export const touchToken = (id) => pool.query('UPDATE inventory_tokens SET last_used_at = NOW() WHERE id = ?', [id]);

export async function listTokens() {
  const [rows] = await pool.query(
    `SELECT t.id, t.label, t.is_active, t.last_used_at, t.created_at, u.name AS created_by_name, (t.token_enc IS NOT NULL) AS has_secret
     FROM inventory_tokens t LEFT JOIN users u ON u.id = t.created_by ORDER BY t.id DESC`
  );
  return rows.map((r) => ({ ...r, has_secret: !!r.has_secret }));
}

export async function createToken(label, hash, enc, userId) {
  const [r] = await pool.query('INSERT INTO inventory_tokens (label, token_hash, token_enc, created_by) VALUES (?, ?, ?, ?)', [label, hash, enc, userId]);
  return r.insertId;
}

export async function findTokenSecret(id) {
  const [[row]] = await pool.query('SELECT token_enc FROM inventory_tokens WHERE id = ?', [id]);
  return row?.token_enc || null;
}

export const setTokenActive = (id, active) => pool.query('UPDATE inventory_tokens SET is_active = ? WHERE id = ?', [active ? 1 : 0, id]);
export const deleteToken = (id) => pool.query('DELETE FROM inventory_tokens WHERE id = ?', [id]);

// ---------- Acceso compartido (solo lectura) ----------

export async function isViewer(userId) {
  const [rows] = await pool.query('SELECT 1 FROM device_viewers WHERE user_id = ?', [userId]);
  return rows.length > 0;
}

export async function listViewers() {
  const [rows] = await pool.query(
    `SELECT v.user_id, u.name, u.email, r.name AS role_name, v.created_at, g.name AS granted_by_name
     FROM device_viewers v JOIN users u ON u.id = v.user_id JOIN roles r ON r.id = u.role_id
     LEFT JOIN users g ON g.id = v.granted_by ORDER BY u.name`
  );
  return rows;
}

export const addViewer = (userId, grantedBy) => pool.query('INSERT IGNORE INTO device_viewers (user_id, granted_by) VALUES (?, ?)', [userId, grantedBy]);
export const removeViewer = (userId) => pool.query('DELETE FROM device_viewers WHERE user_id = ?', [userId]);

export async function findUserBrief(userId) {
  const [[row]] = await pool.query('SELECT u.id, u.name, u.is_active, r.code AS role_code FROM users u JOIN roles r ON r.id = u.role_id WHERE u.id = ?', [userId]);
  return row || null;
}

// ---------- Ingesta ----------

// Foto de lo que hay hoy en BD (para calcular el diff contra el reporte nuevo).
async function snapshotOf(conn, deviceId) {
  const [[dev]] = await conn.query('SELECT hostname, os_name, os_version, ram_mb FROM devices WHERE id = ?', [deviceId]);
  const [disks] = await conn.query('SELECT model, serial, size_mb FROM device_disks WHERE device_id = ?', [deviceId]);
  const [software] = await conn.query('SELECT name, version FROM device_software WHERE device_id = ?', [deviceId]);
  return { dev, disks, software };
}

function diffSnapshots(before, after) {
  const changes = [];
  for (const f of ['hostname', 'os_name', 'os_version', 'ram_mb']) {
    if ((before.dev[f] ?? null) !== (after.dev[f] ?? null)) {
      changes.push({ change_type: 'field', field: f, old_value: before.dev[f], new_value: after.dev[f] });
    }
  }
  const diskKey = (d) => `${d.model || ''}|${d.serial || ''}|${d.size_mb || ''}`;
  const swKey = (s) => `${s.name}|${s.version || ''}`;
  const compare = (a, b, keyFn, labelFn, addType, removeType) => {
    const ka = new Set(a.map(keyFn));
    const kb = new Set(b.map(keyFn));
    for (const x of b) if (!ka.has(keyFn(x))) changes.push({ change_type: addType, field: null, old_value: null, new_value: labelFn(x) });
    for (const x of a) if (!kb.has(keyFn(x))) changes.push({ change_type: removeType, field: null, old_value: labelFn(x), new_value: null });
  };
  compare(before.disks, after.disks, diskKey, (d) => `${d.model || 'Disco'} ${d.size_mb ? Math.round(d.size_mb / 1024) + ' GB' : ''}`.trim(), 'disk_added', 'disk_removed');
  compare(before.software, after.software, swKey, (s) => `${s.name}${s.version ? ` ${s.version}` : ''}`, 'software_installed', 'software_removed');
  return changes;
}

// Upsert por deviceid. Reemplaza todos los componentes dentro de una transaccion y registra el diff.
// Un equipo dado de baja (status=retired) sigue actualizando datos pero NO se reactiva solo.
export async function upsertInventory(deviceid, n, rawFile) {
  const conn = await pool.getConnection();
  try {
    await conn.beginTransaction();
    const [[existing]] = await conn.query('SELECT id FROM devices WHERE deviceid = ? FOR UPDATE', [deviceid]);
    const d = n.device;
    const values = DEVICE_COLS.map((c) => d[c] ?? null);
    const extraJson = Object.keys(n.extra).length ? JSON.stringify(n.extra) : null;

    let deviceId;
    let before = null;
    if (existing) {
      deviceId = existing.id;
      before = await snapshotOf(conn, deviceId);
      await conn.query(
        `UPDATE devices SET ${DEVICE_COLS.map((c) => `${c} = ?`).join(', ')}, last_seen = NOW(), raw_file = ?, extra_json = ? WHERE id = ?`,
        [...values, rawFile, extraJson, deviceId]
      );
      for (const { table } of Object.values(CHILD_TABLES)) await conn.query(`DELETE FROM ${table} WHERE device_id = ?`, [deviceId]);
    } else {
      const [r] = await conn.query(
        `INSERT INTO devices (deviceid, ${DEVICE_COLS.join(', ')}, raw_file, extra_json) VALUES (?, ${DEVICE_COLS.map(() => '?').join(', ')}, ?, ?)`,
        [deviceid, ...values, rawFile, extraJson]
      );
      deviceId = r.insertId;
    }

    for (const [key, { table, cols }] of Object.entries(CHILD_TABLES)) {
      const rows = n[key];
      if (!rows.length) continue;
      await conn.query(
        `INSERT INTO ${table} (device_id, ${cols.join(', ')}) VALUES ?`,
        [rows.map((row) => [deviceId, ...cols.map((c) => row[c] ?? null)])]
      );
    }

    let changeCount = 0;
    if (before) {
      const after = {
        dev: d,
        disks: n.disks,
        software: n.software,
      };
      const changes = diffSnapshots(before, after);
      changeCount = changes.length;
      if (changes.length) {
        await conn.query(
          'INSERT INTO device_changes (device_id, change_type, field, old_value, new_value) VALUES ?',
          [changes.map((c) => [deviceId, c.change_type, c.field, c.old_value == null ? null : String(c.old_value), c.new_value == null ? null : String(c.new_value)])]
        );
      }
    }
    await conn.commit();
    return { id: deviceId, created: !existing, changeCount };
  } catch (err) {
    await conn.rollback();
    throw err;
  } finally {
    conn.release();
  }
}

// ---------- Consultas de la UI ----------

export async function findAll({ search, kind, status, staleDays, diskFull }) {
  const where = [];
  const params = [];
  if (status) { where.push('d.status = ?'); params.push(status); }
  if (kind) { where.push('d.kind = ?'); params.push(kind); }
  if (staleDays) { where.push('d.last_seen < NOW() - INTERVAL ? DAY'); params.push(staleDays); }
  if (diskFull) where.push('d.max_disk_used_pct >= 90');
  if (search) {
    where.push(`(d.hostname LIKE ? OR d.serial LIKE ? OR d.model LIKE ? OR d.ip_main LIKE ? OR d.mac_main LIKE ? OR d.last_user LIKE ? OR u.name LIKE ?)`);
    params.push(...Array(7).fill(`%${search}%`));
  }
  const [rows] = await pool.query(
    `SELECT d.id, d.hostname, d.kind, d.manufacturer, d.model, d.serial, d.os_name, d.os_version, d.ip_main, d.mac_main,
            d.last_user, d.ram_mb, d.disk_total_mb, d.max_disk_used_pct, d.first_seen, d.last_seen, d.status,
            d.assigned_user_id, u.name AS assigned_user_name, d.department_id, dep.name AS department_name
     FROM devices d
     LEFT JOIN users u ON u.id = d.assigned_user_id
     LEFT JOIN departments dep ON dep.id = d.department_id
     ${where.length ? `WHERE ${where.join(' AND ')}` : ''}
     ORDER BY d.hostname`,
    params
  );
  return rows;
}

export async function findById(id) {
  const [[device]] = await pool.query(
    `SELECT d.*, u.name AS assigned_user_name, dep.name AS department_name
     FROM devices d
     LEFT JOIN users u ON u.id = d.assigned_user_id
     LEFT JOIN departments dep ON dep.id = d.department_id
     WHERE d.id = ?`,
    [id]
  );
  if (!device) return null;
  const detail = { ...device, extra: device.extra_json ? JSON.parse(device.extra_json) : null };
  delete detail.extra_json;
  for (const [key, { table }] of Object.entries(CHILD_TABLES)) {
    const order = key === 'software' ? 'name' : 'id';
    const [rows] = await pool.query(`SELECT * FROM ${table} WHERE device_id = ? ORDER BY ${order}`, [id]);
    detail[key] = rows;
  }
  const [changes] = await pool.query(
    'SELECT id, change_type, field, old_value, new_value, created_at FROM device_changes WHERE device_id = ? ORDER BY created_at DESC, id DESC LIMIT 200',
    [id]
  );
  detail.changes = changes;
  return detail;
}

export async function updateManual(id, { status, assignedUserId, departmentId, notes, editVersion }) {
  const [result] = await pool.query(
    'UPDATE devices SET status = ?, assigned_user_id = ?, department_id = ?, notes = ?, edit_version = edit_version + 1 WHERE id = ? AND edit_version = ?',
    [status, assignedUserId, departmentId, notes, id, editVersion]
  );
  return result.affectedRows > 0;
}

export async function findRawFile(id) {
  const [[row]] = await pool.query('SELECT raw_file FROM devices WHERE id = ?', [id]);
  return row?.raw_file || null;
}

// Por defecto solo aplicaciones; `all` incluye actualizaciones/runtimes/drivers (is_component).
export async function listSoftware({ search, all }) {
  const params = [];
  const clauses = [];
  if (!all) clauses.push('s.is_component = 0');
  if (search) { clauses.push('(s.name LIKE ? OR s.publisher LIKE ?)'); params.push(`%${search}%`, `%${search}%`); }
  const where = clauses.length ? `WHERE ${clauses.join(' AND ')}` : '';
  const [rows] = await pool.query(
    `SELECT s.name, MAX(s.publisher) AS publisher, COUNT(DISTINCT s.device_id) AS device_count,
            COUNT(DISTINCT s.version) AS version_count
     FROM device_software s JOIN devices d ON d.id = s.device_id AND d.status = 'active'
     ${where} GROUP BY s.name ORDER BY device_count DESC, s.name LIMIT 1000`,
    params
  );
  return rows.map((r) => ({ ...r, device_count: Number(r.device_count), version_count: Number(r.version_count) }));
}

export async function listDevicesWithSoftware(name) {
  const [rows] = await pool.query(
    `SELECT d.id, d.hostname, d.kind, d.last_user, s.version
     FROM device_software s JOIN devices d ON d.id = s.device_id
     WHERE s.name = ? AND d.status = 'active' ORDER BY d.hostname`,
    [name]
  );
  return rows;
}

export async function dashboard(staleDays) {
  const one = async (sql, params = []) => (await pool.query(sql, params))[0];
  const [[totals]] = await pool.query(
    `SELECT COUNT(*) AS total,
            SUM(last_seen < NOW() - INTERVAL ? DAY) AS stale,
            SUM(max_disk_used_pct >= 90) AS disk_full,
            SUM(ram_mb IS NOT NULL AND ram_mb < 4096) AS low_ram
     FROM devices WHERE status = 'active'`,
    [staleDays]
  );
  const byKind = await one(`SELECT kind AS label, COUNT(*) AS value FROM devices WHERE status = 'active' GROUP BY kind ORDER BY value DESC`);
  const byOs = await one(`SELECT COALESCE(os_name, '—') AS label, COUNT(*) AS value FROM devices WHERE status = 'active' GROUP BY os_name ORDER BY value DESC LIMIT 8`);
  const topSoftware = await one(
    `SELECT s.name AS label, COUNT(DISTINCT s.device_id) AS value
     FROM device_software s JOIN devices d ON d.id = s.device_id AND d.status = 'active'
     WHERE s.is_component = 0
     GROUP BY s.name ORDER BY value DESC LIMIT 8`
  );
  const n = (v) => Number(v || 0);
  return {
    total: n(totals.total), stale: n(totals.stale), diskFull: n(totals.disk_full), lowRam: n(totals.low_ram),
    byKind: byKind.map((r) => ({ ...r, value: n(r.value) })),
    byOs: byOs.map((r) => ({ ...r, value: n(r.value) })),
    topSoftware: topSoftware.map((r) => ({ ...r, value: n(r.value) })),
  };
}