import { existsSync } from 'node:fs';
import { resolve } from 'node:path';

/** Rutas de los archivos de certificado (se leen al arrancar). Con `pfx` o con `key` + `cert`. */
export interface HttpsConfig {
  pfxPath?: string;
  passphrase?: string;
  keyPath?: string;
  certPath?: string;
}

export interface AppConfig {
  port: number;
  webOrigin: string;
  serviceLayer: {
    url: string;
    companyDb: string;
    rejectUnauthorized: boolean;
  };
  dbType: 'HANA' | 'MSSQL';
  cookieSecure: boolean;
  /** Carpeta con el build de Angular que la API sirve; null si no existe (desarrollo con `ng serve`). */
  webDistDir: string | null;
  /** null = la API escucha en HTTP. */
  https: HttpsConfig | null;
  /** Si hay HTTPS: puerto HTTP que redirige al HTTPS (por ejemplo 80). null = no se abre. */
  httpRedirectPort: number | null;
}

const vacio = (v: string | undefined): string | undefined => (v && v.trim() !== '' ? v.trim() : undefined);

function leerHttps(): HttpsConfig | null {
  const pfxPath = vacio(process.env.HTTPS_PFX_PATH);
  const keyPath = vacio(process.env.HTTPS_KEY_PATH);
  const certPath = vacio(process.env.HTTPS_CERT_PATH);

  if (!pfxPath && !keyPath && !certPath) return null;
  if (pfxPath && (keyPath || certPath)) {
    throw new Error('Configure el certificado con HTTPS_PFX_PATH o con HTTPS_KEY_PATH + HTTPS_CERT_PATH, no con ambos.');
  }
  if (!pfxPath && !(keyPath && certPath)) {
    throw new Error('Falta HTTPS_KEY_PATH o HTTPS_CERT_PATH: ambos son necesarios.');
  }
  return { pfxPath, passphrase: vacio(process.env.HTTPS_PFX_PASSPHRASE), keyPath, certPath };
}

/** WEB_DIST_DIR, o el build de Angular junto a la API (apps/web/dist/web/browser) si existe. */
function carpetaWeb(): string | null {
  const configurada = vacio(process.env.WEB_DIST_DIR);
  const ruta = configurada ? resolve(configurada) : resolve(import.meta.dirname, '../../../web/dist/web/browser');
  if (existsSync(resolve(ruta, 'index.html'))) return ruta;
  if (configurada) throw new Error(`WEB_DIST_DIR no contiene un index.html: ${ruta}`);
  return null;
}

export default (): AppConfig => {
  const dbType = (process.env.DB_TYPE ?? 'HANA').toUpperCase();
  if (dbType !== 'HANA' && dbType !== 'MSSQL') {
    throw new Error(`DB_TYPE inválido: ${dbType}. Valores permitidos: HANA, MSSQL.`);
  }

  const url = process.env.SL_URL;
  const companyDb = process.env.SL_COMPANY_DB;
  if (!url || !companyDb) {
    throw new Error('Faltan SL_URL y/o SL_COMPANY_DB en la configuración (.env).');
  }

  return {
    port: Number(process.env.PORT ?? 3000),
    webOrigin: process.env.WEB_ORIGIN ?? 'http://localhost:4200',
    serviceLayer: {
      url: url.replace(/\/+$/, ''),
      companyDb,
      rejectUnauthorized: process.env.SL_REJECT_UNAUTHORIZED !== 'false',
    },
    dbType,
    cookieSecure: process.env.COOKIE_SECURE === 'true',
    webDistDir: carpetaWeb(),
    https: leerHttps(),
    httpRedirectPort: Number(vacio(process.env.HTTP_REDIRECT_PORT)) || null,
  };
};