const { db } = require('../database');
const sql = require('mssql');

let cachedConfig = null;
let lastConfigLoad = 0;
let pool = null;

async function loadConfig() {
  return new Promise((resolve, reject) => {
    db.get('SELECT server, database, username, password FROM mssql_config WHERE id = 1', (err, row) => {
      if (err) {
        return reject(new Error('Fehler beim Lesen der MSSQL-Konfiguration: ' + err.message));
      }
      resolve(row || null);
    });
  });
}

async function getMssqlPool() {
  const now = Date.now();
  if (!cachedConfig || now - lastConfigLoad > 60 * 1000) {
    cachedConfig = await loadConfig();
    lastConfigLoad = now;
  }

  if (!cachedConfig || !cachedConfig.server || !cachedConfig.database || !cachedConfig.username || !cachedConfig.password) {
    throw new Error('MSSQL-Konfiguration ist unvollständig. Bitte im Adminbereich konfigurieren.');
  }

  if (pool && pool.connected) {
    return pool;
  }

  const config = {
    server: cachedConfig.server,
    database: cachedConfig.database,
    user: cachedConfig.username,
    password: cachedConfig.password,
    options: {
      encrypt: false,
      trustServerCertificate: true
    }
  };

  pool = await sql.connect(config);
  return pool;
}

async function searchProjectsByDescription(searchTerm) {
  const pool = await getMssqlPool();
  const request = pool.request();
  request.input('search', sql.NVarChar, `%${searchTerm}%`);

  // Datenbankname aus Konfiguration verwenden
  const dbName = cachedConfig && cachedConfig.database ? cachedConfig.database : null;
  if (!dbName) {
    throw new Error('MSSQL-Datenbankname ist nicht konfiguriert.');
  }

  const query = `
    SELECT TOP 25
      kk.Auftrag AS auftrag,
      kk.Proj   AS proj,
      kk.Such   AS such,
      kk.Knd    AS knd,
      k.Bez     AS bez
    FROM [${dbName}].dbo.KKOPF kk
    LEFT JOIN [${dbName}].dbo.KUNDE k ON kk.Knd = k.Knd
    WHERE kk.Proj    LIKE @search
       OR kk.Auftrag LIKE @search
       OR kk.Such    LIKE @search
       OR k.Bez      LIKE @search
    ORDER BY kk.ErfTerm DESC
  `;

  const result = await request.query(query);
  return result.recordset || [];
}

async function testMssqlConnection() {
  const pool = await getMssqlPool();
  await pool.request().query('SELECT TOP 1 1 AS ok');
  return true;
}

module.exports = {
  getMssqlPool,
  searchProjectsByDescription,
  testMssqlConnection
};