import { parsePhoneNumberFromString } from "libphonenumber-js";
import { COUNTRY_LIST } from "../constants";
import type { CountryItem } from "../types";

const COUNTRY_BY_DIAL_DESC = [...COUNTRY_LIST].sort(
  (a, b) => b.dialCode.length - a.dialCode.length
);

export const sanitizeDigits = (input: string): string => input.replace(/\D/g, "");

export const defaultCountry = (): CountryItem =>
  COUNTRY_LIST.find((country) => country.code === "US") ?? COUNTRY_LIST[0];

export const getCountryByCode = (code?: string | null): CountryItem | null => {
  if (!code) {
    return null;
  }
  return COUNTRY_LIST.find((country) => country.code === code.toUpperCase()) ?? null;
};

export const getCountryByDialPrefix = (phone: string): CountryItem | null => {
  const normalized = phone.trim();
  if (!normalized.startsWith("+")) {
    return null;
  }
  return COUNTRY_BY_DIAL_DESC.find((country) => normalized.startsWith(country.dialCode)) ?? null;
};

export const resolveCountryFromPhone = (
  phone: string,
  userSelectedCode: string | null
): CountryItem => {
  const userSelectedCountry = getCountryByCode(userSelectedCode);
  if (userSelectedCountry) {
    return userSelectedCountry;
  }

  const parsed = parsePhoneNumberFromString(phone);
  const parsedCountry = getCountryByCode(parsed?.country);
  if (parsedCountry) {
    return parsedCountry;
  }

  return getCountryByDialPrefix(phone) ?? defaultCountry();
};

export const getLocalDigits = (phone: string, dialCode: string): string => {
  if (phone.startsWith(dialCode)) {
    return phone.slice(dialCode.length);
  }
  return phone.replace(/^\+/, "");
};

export const filterCountries = (searchText: string): ReadonlyArray<CountryItem> => {
  const query = searchText.trim().toLowerCase();
  if (!query) {
    return COUNTRY_LIST;
  }

  const normalizedDialQuery = query.startsWith("+") ? query : `+${query}`;

  return COUNTRY_LIST.filter((country) => {
    return (
      country.name.toLowerCase().includes(query) ||
      country.code.toLowerCase().includes(query) ||
      country.dialCode.includes(query) ||
      country.dialCode.includes(normalizedDialQuery)
    );
  });
};