import { get } from 'lodash';
import SalesTaxRates from 'sales-tax/res/sales_tax_rates.json';

import { TierType } from './types/TierType';

export const GST_RATE_PERCENT = Math.round(SalesTaxRates['NZ'].rate * 100);

type GSTSettings = {
  number?: string;
  type?: 'OWN' | 'HOST';
  disabled?: boolean;
};

/**
 * Returns true if GST is enabled for this account
 */
export const accountHasGST = (
  account: {
    settings?: {
      GST?: GSTSettings;
      parent?: { settings?: { GST?: GSTSettings } };
      parentCollective?: { settings?: { GST?: GSTSettings } };
    };
  } | null,
): boolean => {
  return Boolean(
    get(account, 'settings.GST') ||
    get(account, 'parent.settings.GST') ||
    get(account, 'parentCollective.settings.GST'),
  );
};

/**
 * Returns true if the given tier type can be subject to VAT
 */
export const isTierTypeSubjectToGST = (tierType: TierType | `${TierType}`): boolean => {
  const taxedTiersTypes: string[] = [TierType.SUPPORT, TierType.SERVICE, TierType.PRODUCT, TierType.TICKET];
  return taxedTiersTypes.includes(tierType);
};

/**
 * Returns true if GST may apply.
 *
 * @param tierType - the tier type (eg. SUPPORT, TICKET...)
 * @param originCOuntry - two letters country where GST is applied
 */
export const gstMayApply = (tierType: TierType | `${TierType}`): boolean => {
  return isTierTypeSubjectToGST(tierType);
};

/**
 * Calculates the GST rate.
 *
 * @param tierType - the tier type (eg. SUPPORT, TICKET...)
 * @param originCountry - two letters country where GST is applied
 * @param userCountry - two letters country code of the payer
 *
 * @returns {Number} `0` if no GST applies or the percentage as a number between 0 and 100
 */
export const getGstPercentage = (
  tierType: TierType | `${TierType}`,
  originCountry: string | null,
  userCountry: string | null,
): number => {
  if (originCountry === 'NZ' && userCountry === 'NZ' && gstMayApply(tierType)) {
    return GST_RATE_PERCENT;
  } else {
    return 0;
  }
};