import { UserNameType } from './userNameType';
import { JWT, JSONWebToken } from '../jwt/jwt';

/**
 * Represents a user's identity using a user's name name and a type of the name.
 * This class is typially used to pass a user name during authentication.
 */
export class User
{
    /** User name. Must be defined in one of supported formats (see {@link UserNameType}) */
    public readonly name: string;
    /** Format of the user name */
    public readonly type: UserNameType;

    /** Constructs the object using a username and a user type.
     * @param name - user name. No name transformation/canonicalization is performed.
     * @param type - an optional type of the user. If not provided, he type is deduced automatically.
     * @remarks
     * If no `type` parameter is provided, the username format is analyzes and automatic type is assigned.
     * For example:
     * * "user\@comtoso.com" name will be parsed as a {@link UserNameType.UPN | User Principal Name (UPN)},
     * * "Domain\\UserX" name will be parsed as a {@link UserNameType.SAM | Security Account Manager (SAM)} name,
     * * "6de5b5ed-85fc-4298-a18b-dac7d5a18369" will be parsed as a {@link UserNameType.UID | Unique Identifier (UID)} name,
     * * "UserX" name will be parsed as a {@link UserNameType.DP | DigitalPersona name} (used in LDS)
     * You may provide a `type` parameter if you want to enforce a specific name type.
     */
    public constructor(name: string, type?: UserNameType) {
        const reGUID = /^[0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{12}$/;
        this.name = name || "";
        this.type = type || (
            (this.name.length === 0)            ? UserNameType.Unknown :
            (this.name === "*")                 ? UserNameType.Unknown :
            (this.name.indexOf('@') !== -1)     ? UserNameType.UPN :
            (this.name.indexOf('\\') !== -1)    ? UserNameType.SAM :
            reGUID.test(this.name)              ? UserNameType.UID
                                                : UserNameType.DP);
    }

    /** @returns `true` when the User object represents an anonymous user. */
    public isAnonymous(): boolean {
        return !this.name || this.name.length === 0;
    }

    /** @returns `true` whrn the user object represents any user. */
    public isEveryone(): boolean {
        return this.name === "*";
    }

    /** Creates a user object representing an anonymous user. */
    public static Anonymous(): User
    {
        return new User("", UserNameType.Unknown);
    }

    /** Creates a user object representing every user. */
    public static Everyone(): User {
        return new User("*", UserNameType.Unknown);
    }

    /** Creates a user object using claims in a JSON Web Token.
     * @param token - a JSON Web Token.
     * @param type - an optional username type to override automatic type detection and force a specific name format.
     * @returns a user object constructed from the `token` claims.
     * @remarks
     * The `token` should contain either {@link ClaimSet.sub |`sub`} or {@link ClaimSet.wan | `wan`} claim
     * to detect a user name. If no such claims are found, then {@link User.Anonymous | anonymous} user is returned.
     * The {@link ClaimSet.sub |`sub`} claim has a priority over the {@link ClaimSet.wan | `wan`} claim.
     * If `type` parameter is not defined, the name type is deduced automatically from the name string.
     * You may provide a `type` parameter if you want to enforce a specific name type.
     * See {@link User.constructor} for type deduction details.
     */
    public static fromJWT(token: JSONWebToken, type?: UserNameType): User
    {
        const claims = JWT.claims(token);
        const user = claims.sub && (claims.sub instanceof User) ? claims.sub :
                     claims.wan ? new User(claims.wan, type) :
                     claims.sub ? new User(claims.sub, type || UserNameType.DP) : User.Anonymous();
        return user;
    }
}