import { client } from "../backend/helper";

type Claim = "role" | "person_row_id" | "exp" | "iat" | "aud" | "iss";

export type UppercaseUserRole =
  | "KANDIMAT_PERSON"
  | "KANDIMAT_EDITOR"
  | "KANDIMAT_CANDIDATE";

export type UserRole =
  | "kandimat_editor"
  | "kandimat_candidate"
  | "kandimat_person";

export interface JwtPayload {
  role: UserRole;
  person_row_id: number;
  exp: number;
  iat: number;
  aud: "postgraphile";
  iss: "postgraphile";
}

const CLAIMS: Claim[] = ["role", "person_row_id", "exp", "iat", "aud", "iss"];

export const UPPERCASE_USER_ROLES: UppercaseUserRole[] = [
  "KANDIMAT_PERSON",
  "KANDIMAT_EDITOR",
  "KANDIMAT_CANDIDATE",
];

export const USER_ROLES: UserRole[] = [
  "kandimat_editor",
  "kandimat_candidate",
  "kandimat_person",
];

export const getRawJsonWebToken = (): string | null => {
  return localStorage.getItem("token");
};

export const isJwtPayloadValid = (jwtPayload: unknown): boolean => {
  const jwt = Object(jwtPayload);
  return (
    CLAIMS.every((claim) => Object.keys(jwt).includes(claim)) &&
    USER_ROLES.includes(jwt.role) &&
    typeof jwt.person_row_id === "number" &&
    typeof jwt.exp === "number" &&
    typeof jwt.iat === "number"
  );
};

export const parseJwt = (token: string): JwtPayload | null => {
  try {
    const base64Url = token.split(".")[1];
    const base64 = base64Url.replace(/-/g, "+").replace(/_/g, "/");
    const jsonPayload = decodeURIComponent(
      atob(base64)
        .split("")
        .map((c) => "%" + ("00" + c.charCodeAt(0).toString(16)).slice(-2))
        .join("")
    );
    const jwtPayload = JSON.parse(jsonPayload);
    return isJwtPayloadValid(jwtPayload) ? jwtPayload : null;
  } catch {
    return null;
  }
};

export const getJsonWebToken = (): JwtPayload | null => {
  const rawToken = getRawJsonWebToken();
  return rawToken ? parseJwt(rawToken) : null;
};

export const logoutUser = async (): Promise<void> => {
  try {
    await client.cache.reset();
  } catch (e) {
    console.error(e);
  }
  localStorage.removeItem("token");
  window.location.reload();
};

export const isLoggedIn = (): boolean => !!getJsonWebToken();