export interface FuelConfig {
  rendimientoKmL: number | null;
  precioPorLitro: number | null;
}

export function currencyForCountry(country: string | null | undefined): string {
  const normalized = (country ?? '')
    .normalize('NFD')
    .replace(/[\u0300-\u036f]/g, '')
    .replace(/[^a-z0-9]/gi, '')
    .toLowerCase();
  if (!normalized) return '$';
  if (['mexico', 'mx', 'cdmx', 'ciudaddemexico', 'mexicocity', 'estadosunidosmexicanos'].includes(normalized)) return 'MX$';
  if (['republicadominicana', 'dominicana', 'rd', 'do', 'santodomingo'].includes(normalized)) return 'RD$';
  return '$';
}

export function isFuelConfigured(config: FuelConfig): boolean {
  return (
    config.rendimientoKmL != null &&
    config.precioPorLitro != null &&
    Number.isFinite(config.rendimientoKmL) &&
    Number.isFinite(config.precioPorLitro) &&
    config.rendimientoKmL > 0 &&
    config.precioPorLitro >= 0
  );
}

export function fuelLiters(distanceKm: number, rendimientoKmL: number): number {
  if (!Number.isFinite(distanceKm) || distanceKm <= 0) return 0;
  if (!Number.isFinite(rendimientoKmL) || rendimientoKmL <= 0) return 0;
  return distanceKm / rendimientoKmL;
}

export function fuelCost(distanceKm: number, config: FuelConfig): { liters: number; cost: number } {
  if (!isFuelConfigured(config)) return { liters: 0, cost: 0 };
  const liters = fuelLiters(distanceKm, config.rendimientoKmL as number);
  return { liters, cost: liters * (config.precioPorLitro as number) };
}

export function formatFuelCost(cost: number, currency: string): string {
  return `${currency} ${cost.toFixed(2)}`;
}