import { inject, Injectable } from "@angular/core";
import { User } from "../model/User";
import { UserRestService } from "../rest-services/user/user.rest-service";
import { RefreshTokenRequest } from "../rest-services/user/model/refresh-token.model";

const JWT_PARAM = 'jwt';
const REFRESH_TOKEN_PARAM = 'refresh-token';

interface UserDetails {
    sub: string;
    exp: number;
    email: string;
    pseudo: string;
    roles: string;
}

@Injectable({
    providedIn: 'root'
})
export class AuthenticationService {

    authenticate(token: string, refreshToken: string): void {
        localStorage.setItem(JWT_PARAM, token);
        localStorage.setItem(REFRESH_TOKEN_PARAM, refreshToken);
    }

    unauthenticate(): void {
        localStorage.removeItem(JWT_PARAM);
    }
    
    isAuthenticated(): boolean {
        let result = false;

        const userDetails = this.extractUserDetails();
        
        if (userDetails) {
            const authenticationExpiration = new Date(userDetails.exp * 1000);
            result = authenticationExpiration > new Date();
        }

        return result;
    }

    getAuthenticatedUser(): User | undefined {
        return this.extractUserFromLocalStorage();
    }

    getToken(): string | undefined {
        return localStorage.getItem(JWT_PARAM) ?? undefined;
    }

    getRefreshToken(): string | undefined {
        return localStorage.getItem(REFRESH_TOKEN_PARAM) ?? undefined;
    }

    isTokenExpired(): boolean {
        let result = false;

        const userDetails = this.extractUserDetails();

        if (userDetails) {
            const expirationDate = new Date(userDetails.exp * 1000);
            const now = new Date();

            result = expirationDate < now;
        }

        return result;
    }

    private extractUserFromLocalStorage(): User | undefined {
        let result: User | undefined = undefined;

        const userDetails = this.extractUserDetails();
        if (userDetails) {
            const user = this.convertToUser(userDetails);
            result = user;
        }

        return result;
    }

    private extractUserDetails(): UserDetails | undefined {
        let result: UserDetails | undefined = undefined;

        const token = localStorage.getItem(JWT_PARAM);

        const tokenParts = token?.split('.');
        if (tokenParts?.length === 3 && tokenParts[1].length) {
            const decodedTokenPart = atob(tokenParts[1]);
            const userDetails: UserDetails = JSON.parse(decodedTokenPart);
            result = userDetails;
        }

        return result;
    }

    private convertToUser(userDetails: UserDetails): User {
        return {
            id: userDetails.sub,
            email: userDetails.email,
            pseudo: userDetails.pseudo,
            roles: userDetails.roles.split(',')
        };
    }
}