import { omitUndefinedKeys } from "./omitUndefinedKeys.ts";
import type { LinkUtmParams, createUtm } from "./utm.ts";

export function withParams(path: string, params?: Record<string, string>) {
  if (!params) {
    return path;
  }

  const cleanParams = omitUndefinedKeys(params);
  if (Object.keys(cleanParams).length === 0) {
    return path;
  }

  return `${path}?${new URLSearchParams(cleanParams)}`;
}

export type AccountParams = {
  redirectTo?: string;
  backTo?: string;
};

export type BuyParams = {
  note?: "continuePurchase" | "loginNeeded";
};

type InputAppHrefs = {
  login?: (params?: AccountParams) => string;
  join?: (params?: AccountParams) => string;
  password?: () => string;

  dashboard?: () => string;
  account: () => string;

  // These are usually external links to the root domain, so we want to be
  // able to set some tracking params.
  terms?: (linkUtm?: LinkUtmParams) => string;
  privacy?: (linkUtm?: LinkUtmParams) => string;
  cookies?: (linkUtm?: LinkUtmParams) => string;
};

export type AppHrefs = Required<InputAppHrefs>;

export function createHrefs<T extends InputAppHrefs>(params: {
  /**
   * Hrefs to be used for the given app. At minimum, you need to provide
   * the core hrefs required by Appkit.
   */
  hrefs: T;

  /**
   * The function responsible for generating UTM tags. You should
   * use the return value of {@link createUtm} unless you are doing something
   * unusual.
   */
  utm: ReturnType<typeof createUtm>;
}) {
  const { utm, hrefs } = params;

  return {
    dashboard: () => `~/`,

    login: (params?: AccountParams) => withParams(`~/login`, params),
    join: (params?: AccountParams) => withParams(`~/join`, params),
    password: () => `~/password`,

    terms: (linkUtm?: LinkUtmParams) =>
      `https://indietabletop.club/terms?${utm(linkUtm)}`,
    privacy: (linkUtm?: LinkUtmParams) =>
      `https://indietabletop.club/privacy?${utm(linkUtm)}`,
    cookies: (linkUtm?: LinkUtmParams) =>
      `https://indietabletop.club/cookies?${utm(linkUtm)}`,
    itc: (linkUtm?: LinkUtmParams) =>
      `https://indietabletop.club?${utm(linkUtm)}`,
    fathom: () => `https://usefathom.com`,

    ...hrefs,
  };
}