import { writable } from 'svelte/store';

export interface AuthUser {
	id: string;
	email: string;
}

export type AuthState =
	| { status: 'unknown' }
	| { status: 'authenticated'; user: AuthUser }
	| { status: 'unauthenticated' };

function createAuthStore() {
	const { subscribe, set } = writable<AuthState>({ status: 'unknown' });

	/** Calls GET /api/v1/auth/me and updates the store. Never throws. */
	async function refresh(): Promise<AuthState> {
		try {
			const res = await fetch('/api/v1/auth/me', { credentials: 'include' });
			if (res.ok) {
				const user = (await res.json()) as AuthUser;
				const next: AuthState = { status: 'authenticated', user };
				set(next);
				return next;
			}
		} catch {
			// Network failure: fall through to unauthenticated. The login page's own
			// fetch will surface a retry message if the user tries to act.
		}
		const next: AuthState = { status: 'unauthenticated' };
		set(next);
		return next;
	}

	async function logout(): Promise<void> {
		try {
			await fetch('/api/v1/auth/logout', { method: 'POST', credentials: 'include' });
		} finally {
			set({ status: 'unauthenticated' });
		}
	}

	return { subscribe, refresh, logout };
}

export const auth = createAuthStore();