import { URL } from "url";
import _ from "lodash";

const DEFAULT_REMOVED_QUERY_PARAMS = [
  "utm_campaign",
  "utm_source",
  "utm_content",
  "utm_term",
  "Utm_viral",
  "utm_medium",
  "utm_identifier",
  "utm_key",
  "fb_source",
  "referrer",
  "referer",
  "ref",
  "Rand",
  "rnd",
  "randid",
  ".?rand",
  ".?partner",
  "cb",
  "count",
  "adid",
  "session",
  "sessionid",
  "session_redirect",
  "paramd",
  "userinfo",
  "uid",
  "refresh",
  "ocid",
  "ncid",
  "clickenc",
  "fbclid",
  "Amp_js_v",
  "amp_gsa",
  "ns_source",
  "ns_campaign",
  "ns_mchanel",
  "ns_mchannel",
  "Ns_linkname",
  "ns_fee",
  "src",
  "ex_cid",
  "usqp",
  "source",
  "xid",
  "trkid",
  "utm_social-type",
  "mbid",
  "utm_brand",
  "__twitter_impression",
  "utm_referrer",
  "CMP",
];

const paramRemovalPatterns: Record<string, RegExp> = _.mapValues(
  {
    default: DEFAULT_REMOVED_QUERY_PARAMS,
    "trivia.com": ["guid", "dicbo", ...DEFAULT_REMOVED_QUERY_PARAMS],
  },
  createQueryParamRegExp
);

const pathRemovalPatterns: Record<string, RegExp[]> = {
  default: [/\/amp(?:\/[?&]*)?$/],
};
const protocolRemovalPatterns: Record<string, RegExp[]> = {
  default: [/^(https?:\/\/)?(www\.)?/],
};

const domainSanitizationPattern = /^www\./;

export const sanitizeURL = (url: string): string => {
  const parsed = new URL(url);

  const domain = parsed.hostname.replace(domainSanitizationPattern, "");

  const pathRemovalPattern = pathRemovalPatterns[domain] || pathRemovalPatterns.default;
  const paramRemovalPattern = paramRemovalPatterns[domain] || paramRemovalPatterns.default;

  for (const pattern of [...pathRemovalPattern, paramRemovalPattern]) {
    url = url.replace(pattern, "");
  }

  // ┌────────────────────────────────────────────────────────────────────────────────────────────────┐
  // │                                              href                                              │
  // ├──────────┬──┬─────────────────────┬────────────────────────┬───────────────────────────┬───────┤
  // │ protocol │  │        auth         │          host          │           path            │ hash  │
  // │          │  │                     ├─────────────────┬──────┼──────────┬────────────────┤       │
  // │          │  │                     │    hostname     │ port │ pathname │     search     │       │
  // │          │  │                     │                 │      │          ├─┬──────────────┤       │
  // │          │  │                     │                 │      │          │ │    query     │       │
  // "  https:   //    user   :   pass   @ sub.example.com : 8080   /p/a/t/h  ?  query=string   #hash "
  // │          │  │          │          │    hostname     │ port │          │                │       │
  // │          │  │          │          ├─────────────────┴──────┤          │                │       │
  // │ protocol │  │ username │ password │          host          │          │                │       │
  // ├──────────┴──┼──────────┴──────────┼────────────────────────┤          │                │       │
  // │   origin    │                     │         origin         │ pathname │     search     │ hash  │
  // ├─────────────┴─────────────────────┴────────────────────────┴──────────┴────────────────┴───────┤
  // │                                              href                                              │
  // └────────────────────────────────────────────────────────────────────────────────────────────────┘
  // add a / for homepage url => no pathname or only /, no search, no hash, not ends with /, ?, #
  const urlWithProtocol = new URL(url);
  if (
    urlWithProtocol.pathname === "/" &&
    urlWithProtocol.search === "" &&
    urlWithProtocol.hash === "" &&
    !url.endsWith("/")
  ) {
    // remove ? if no query string
    if (url.endsWith("?")) {
      url = url.slice(0, -1);
    }
    url += "/";
  }

  const protocolRemovalPattern = protocolRemovalPatterns[domain] || protocolRemovalPatterns.default;
  for (const pattern of [...protocolRemovalPattern]) {
    url = url.replace(pattern, "");
  }
  return url;
};

function createQueryParamRegExp(params: string[]) {
  return new RegExp(`(((?<=\\?)|&|%3F|%26|;)(?:${params.join("|")})=[^&]*)`, "g");
}