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mobilizon.chapril.org-mobil.../js/src/services/AnonymousParticipationStora...

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import { IEvent } from "@/types/event.model";
const ANONYMOUS_PARTICIPATIONS_LOCALSTORAGE_KEY = "ANONYMOUS_PARTICIPATIONS";
interface IAnonymousParticipation {
token: string;
expiration: Date;
confirmed: boolean;
}
class AnonymousParticipationNotFoundError extends Error {
constructor(message?: string) {
super(message);
Object.setPrototypeOf(this, new.target.prototype);
this.name = AnonymousParticipationNotFoundError.name;
}
}
function jsonToMap(jsonStr: string): Map<string, IAnonymousParticipation> {
return new Map(JSON.parse(jsonStr));
}
function mapToJson(map: Map<any, any>): string {
return JSON.stringify([...map]);
}
/**
* Fetch existing anonymous participations saved inside this browser
*/
function getLocalAnonymousParticipations(): Map<
string,
IAnonymousParticipation
> {
return jsonToMap(
localStorage.getItem(ANONYMOUS_PARTICIPATIONS_LOCALSTORAGE_KEY) ||
mapToJson(new Map())
);
}
/**
* Purge participations which expiration has been reached
* @param participations Map
*/
function purgeOldParticipations(
participations: Map<string, IAnonymousParticipation>
): Map<string, IAnonymousParticipation> {
// eslint-disable-next-line no-restricted-syntax
for (const [hashedUUID, { expiration }] of participations) {
if (expiration < new Date()) {
participations.delete(hashedUUID);
}
}
return participations;
}
/**
* Insert a participation in the list of anonymous participations
* @param hashedUUID
* @param participation
*/
function insertLocalAnonymousParticipation(
hashedUUID: string,
participation: IAnonymousParticipation
) {
const participations = purgeOldParticipations(
getLocalAnonymousParticipations()
);
participations.set(hashedUUID, participation);
localStorage.setItem(
ANONYMOUS_PARTICIPATIONS_LOCALSTORAGE_KEY,
mapToJson(participations)
);
}
function buildExpiration(event: IEvent): Date {
const expiration = event.endsOn || event.beginsOn;
expiration.setMonth(expiration.getMonth() + 1);
return expiration;
}
async function digestMessage(message: string): Promise<string> {
const encoder = new TextEncoder();
const data = encoder.encode(message);
const hashBuffer = await crypto.subtle.digest("SHA-256", data);
const hashArray = Array.from(new Uint8Array(hashBuffer));
return hashArray.map((b) => b.toString(16).padStart(2, "0")).join("");
}
async function addLocalUnconfirmedAnonymousParticipation(
event: IEvent,
cancellationToken: string
): Promise<void> {
/**
* We hash the event UUID so that we can't know which events
* an anonymous user goes by looking up it's localstorage
*/
const hashedUUID = await digestMessage(event.uuid);
/**
* We round expiration to first day of next 3 months so that
* it's difficult to find event from date
*/
const expiration = buildExpiration(event);
insertLocalAnonymousParticipation(hashedUUID, {
token: cancellationToken,
expiration,
confirmed: false,
});
}
async function confirmLocalAnonymousParticipation(uuid: string): Promise<void> {
const participations = purgeOldParticipations(
getLocalAnonymousParticipations()
);
const hashedUUID = await digestMessage(uuid);
const participation = participations.get(hashedUUID);
if (participation) {
participation.confirmed = true;
participations.set(hashedUUID, participation);
localStorage.setItem(
ANONYMOUS_PARTICIPATIONS_LOCALSTORAGE_KEY,
mapToJson(participations)
);
}
}
async function getParticipation(
eventUUID: string
): Promise<IAnonymousParticipation> {
const hashedUUID = await digestMessage(eventUUID);
const participation = purgeOldParticipations(
getLocalAnonymousParticipations()
).get(hashedUUID);
if (participation) {
return participation;
}
throw new AnonymousParticipationNotFoundError("Participation not found");
}
async function isParticipatingInThisEvent(eventUUID: string): Promise<boolean> {
const participation = await getParticipation(eventUUID);
return participation !== undefined && participation.confirmed;
}
async function getLeaveTokenForParticipation(
eventUUID: string
): Promise<string> {
return (await getParticipation(eventUUID)).token;
}
async function removeAnonymousParticipation(eventUUID: string): Promise<void> {
const hashedUUID = await digestMessage(eventUUID);
const participations = purgeOldParticipations(
getLocalAnonymousParticipations()
);
participations.delete(hashedUUID);
localStorage.setItem(
ANONYMOUS_PARTICIPATIONS_LOCALSTORAGE_KEY,
mapToJson(participations)
);
}
function removeAllAnonymousParticipations(): void {
localStorage.removeItem(ANONYMOUS_PARTICIPATIONS_LOCALSTORAGE_KEY);
}
export {
addLocalUnconfirmedAnonymousParticipation,
confirmLocalAnonymousParticipation,
getLeaveTokenForParticipation,
isParticipatingInThisEvent,
removeAnonymousParticipation,
removeAllAnonymousParticipations,
AnonymousParticipationNotFoundError,
};