import { error, fail, redirect } from '@sveltejs/kit';
import type { Actions, PageServerLoad } from './$types';
import {
	countAdmins,
	createUser,
	deleteUser,
	getUser,
	getUserByEmail,
	listUsers,
	parseRole,
	setUserPassword,
	updateUserRole
} from '$lib/server/users';

function requireAdmin(locals: App.Locals) {
	if (!locals.user || locals.user.role !== 'admin') {
		throw error(403, 'Samo administratorji lahko upravljajo uporabnike.');
	}
	return locals.user;
}

export const load: PageServerLoad = ({ locals }) => {
	// Editors don't manage users — send them back to the gallery.
	if (!locals.user || locals.user.role !== 'admin') {
		throw redirect(303, '/admin/gallery');
	}
	return { users: listUsers(), currentUserId: locals.user.id };
};

export const actions: Actions = {
	create: async ({ request, locals }) => {
		requireAdmin(locals);
		const form = await request.formData();
		const email = String(form.get('email') ?? '')
			.trim()
			.toLowerCase();
		const name = String(form.get('name') ?? '').trim();
		const password = String(form.get('password') ?? '');
		const role = parseRole(form.get('role'));

		if (!email || !name || !password || !role) {
			return fail(400, { error: 'Izpolnite vsa polja.' });
		}
		if (password.length < 8) {
			return fail(400, { error: 'Geslo mora imeti vsaj 8 znakov.' });
		}
		if (getUserByEmail(email)) {
			return fail(400, { error: 'Uporabnik s tem e-naslovom že obstaja.' });
		}

		await createUser({ email, name, password, role });
		return { success: `Uporabnik ${email} dodan.` };
	},

	setRole: async ({ request, locals }) => {
		requireAdmin(locals);
		const form = await request.formData();
		const id = String(form.get('id') ?? '');
		const role = parseRole(form.get('role'));
		if (!role) return fail(400, { error: 'Neveljavna vloga.' });

		const target = getUser(id);
		if (!target) return fail(404, { error: 'Uporabnik ne obstaja.' });

		if (target.role === 'admin' && role === 'editor' && countAdmins() <= 1) {
			return fail(400, { error: 'Vsaj en administrator mora ostati.' });
		}

		updateUserRole(id, role);
		return { success: 'Vloga posodobljena.' };
	},

	resetPassword: async ({ request, locals }) => {
		requireAdmin(locals);
		const form = await request.formData();
		const id = String(form.get('id') ?? '');
		const password = String(form.get('password') ?? '');
		if (password.length < 8) {
			return fail(400, { error: 'Geslo mora imeti vsaj 8 znakov.' });
		}
		if (!getUser(id)) return fail(404, { error: 'Uporabnik ne obstaja.' });

		await setUserPassword(id, password);
		return { success: 'Geslo posodobljeno.' };
	},

	delete: async ({ request, locals }) => {
		const admin = requireAdmin(locals);
		const form = await request.formData();
		const id = String(form.get('id') ?? '');

		if (id === admin.id) {
			return fail(400, { error: 'Ne morete izbrisati lastnega računa.' });
		}
		const target = getUser(id);
		if (!target) return fail(404, { error: 'Uporabnik ne obstaja.' });
		if (target.role === 'admin' && countAdmins() <= 1) {
			return fail(400, { error: 'Vsaj en administrator mora ostati.' });
		}

		deleteUser(id);
		return { success: 'Uporabnik izbrisan.' };
	}
};