import { browser } from "$app/environment";
import type { UserIdentity } from "$lib/Data/AniList/identity";
import { writable } from "svelte/store";
import localforage from "localforage";

export const defaultIdentity: UserIdentity = {
	name: "",
	id: -2,
	avatar: "https://s4.anilist.co/file/anilistcdn/user/avatar/large/default.png",
};

const createStore = () => {
	const store = writable<UserIdentity>(defaultIdentity);
	let state: UserIdentity = defaultIdentity;
	let hydrated = !browser;
	let changedBeforeHydration = false;
	let initialEmission = true;
	let applyingStoredValue = false;

	store.subscribe((value) => {
		state = value;

		if (browser && !hydrated && !initialEmission && !applyingStoredValue)
			changedBeforeHydration = true;

		if (browser && hydrated) localforage.setItem("identity", value);

		initialEmission = false;
	});

	if (browser)
		localforage.getItem<UserIdentity>("identity").then(async (value) => {
			if (value && typeof value === "object" && !changedBeforeHydration) {
				applyingStoredValue = true;
				store.set(value);
				applyingStoredValue = false;
			}

			hydrated = true;

			await localforage.setItem("identity", state);
		});

	return {
		subscribe: store.subscribe,
		set: store.set,
		update: store.update,
		reset: () => store.set(defaultIdentity),

		get: () => {
			const keys = Object.keys(defaultIdentity);
			const identityKeys = Object.keys(state);
			const updatedIdentity = { ...state };

			for (const key of keys)
				if (!identityKeys.includes(key))
					(updatedIdentity as unknown as Record<string, unknown>)[key] = (
						defaultIdentity as unknown as Record<string, unknown>
					)[key];

			if (browser && hydrated) localforage.setItem("identity", updatedIdentity);

			return updatedIdentity;
		},

		setKey: (key: keyof UserIdentity, value: unknown) =>
			store.update((identity) => ({ ...identity, [key]: value })),
	};
};

const identity = createStore();

export default identity;