Implement database administration

Add routes and admin panel elements for creating a database backup,
restoring from a backup, deleting the existing schedule, and replacing
the database with the demo schedule.  These server as crude ways to
manage the data stored in the system.

pages/admin.vue

@@ -1,12 +1,102 @@
 <template>
 	<main>
 		<h1>Admin</h1>
-		<h2>Users</h2>
+		<Tabs
-		<TableUsers />
+			:tabs
+			default="users"
+		>
+			<template #users>
+				<TableUsers />
+			</template>
+			<template #database>
+				<p>
+					To backup the database you can create and download a
+					database snapshot. This will export all schedule and user
+					data stored on the server into a single JSON file that can
+					then later be used to replace the exsting content of the
+					database to restore the system to the state it was in when
+					the snapshot was created.
+				</p>
+				<form
+					action="/api/admin/database-export"
+					method="post"
+				>
+					<p>
+						<button type="submit">
+							Download snapshot
+						</button>
+					</p>
+				</form>
+				<fieldset>
+					<legend>Restore Database</legend>
+					<p>
+						To restore the system to a previous state you can load a
+						database snapshot obtained from previously running the
+						database snapshot tool above. This will delete all
+						changes including new events, shifts, users and user
+						data that has created since the snapshot was created.
+					</p>
+					<form
+						action="/api/admin/database-import"
+						enctype="multipart/form-data"
+						method="post"
+					>
+						<p>
+							<label>
+								Database snapshot:
+								<input name="snapshot" type="file">
+							</label>
+						</p>
+						<p>
+							<button type="submit">
+								Restore database
+							</button>
+						</p>
+					</form>
+				</fieldset>
+				<fieldset>
+					<legend>Danger Zone</legend>
+					<p>
+						If you wish to start over with the schedule, you can use
+						this button to delete the current schedule.
+					</p>
+					<form
+						action="/api/admin/delete-schedule"
+						method="post"
+					>
+						<p>
+							<button type="submit">
+								Delete schedule
+							</button>
+						</p>
+					</form>
+					<p>
+						If you wish to see a demo of how the system can be used
+						you can replace the existing schedule with a generated
+						demo schedule that shows off all the features. <b>This
+						will delete all existing data including users!</b>
+					</p>
+					<form
+						action="/api/admin/database-import-demo"
+						method="post"
+					>
+						<p>
+							<button type="submit">
+								Replace with demo
+							</button>
+						</p>
+					</form>
+				</fieldset>
+			</template>
+		</Tabs>
 	</main>
 </template>
 
 <script lang="ts" setup>
+const tabs = [
+	{ id: "users", title: "Users" },
+	{ id: "database", title: "Database" },
+];
 </script>
 
 <style>

server/api/admin/database-export.post.ts

@@ -0,0 +1,15 @@
+import { readNextSessionId, readNextUserId, readSchedule, readSessions, readSubscriptions, readUsers } from "~/server/database";
+
+export default defineEventHandler(async (event) => {
+	await requireServerSessionWithAdmin(event);
+	setHeader(event, "Content-Disposition", 'attachment; filename="database-dump.json"');
+	setHeader(event, "Content-Type", "application/json; charset=utf-8");
+	return {
+		nextUserId: await readNextUserId(),
+		users: await readUsers(),
+		nextSessionId: await readNextSessionId(),
+		sessions: await readSessions(),
+		subscriptions: await readSubscriptions(),
+		schedule: await readSchedule(),
+	};
+})

server/api/admin/database-import-demo.post.ts

@@ -0,0 +1,7 @@
+import { writeSchedule, writeUsers } from "~/server/database";
+import { generateDemoSchedule, generateDemoAccounts } from "~/server/generate-demo-schedule";
+export default defineEventHandler(async (event) => {
+	await requireServerSessionWithAdmin(event);
+	await writeUsers(generateDemoAccounts());
+	await writeSchedule(generateDemoSchedule());
+})

server/api/admin/database-import.post.ts

@@ -0,0 +1,44 @@
+import { readNextSessionId, readNextUserId, readSessions, type ServerSession, type ServerUser, writeNextSessionId, writeNextUserId, writeSchedule, writeSessions, writeSubscriptions, writeUsers } from "~/server/database";
+import type { ApiSchedule, ApiSubscription } from "~/shared/types/api";
+
+export default defineEventHandler(async (event) => {
+	await requireServerSessionWithAdmin(event);
+	const formData = await readMultipartFormData(event);
+	let snapshot: undefined | {
+		nextUserId: number,
+		users: ServerUser[],
+		nextSessionId: number,
+		sessions: ServerSession[],
+		subscriptions: ApiSubscription[],
+		schedule: ApiSchedule,
+	};
+	for (const part of formData ?? []) {
+		if (part.name === "snapshot") {
+			snapshot = JSON.parse(part.data.toString("utf-8"));
+		}
+	}
+	if (!snapshot) {
+		throw createError({
+			statusCode: 400,
+			statusMessage: "Bad Request",
+			message: "snapshot missing."
+		});
+	}
+
+	const currentNextUserId = await readNextUserId();
+	await writeNextUserId(Math.max(currentNextUserId, snapshot.nextUserId));
+	await writeUsers(snapshot.users);
+	const currentNextSessionId = await readNextSessionId();
+	await writeNextSessionId(Math.max(currentNextSessionId, snapshot.nextSessionId));
+	const currentSessions = new Map((await readSessions()).map(session => [session.id, session]));
+	await writeSessions(snapshot.sessions.filter(session => {
+		const current = currentSessions.get(session.id);
+		// Only keep sessions that match the account id in both sets to avoid
+		// resurrecting deleted sessions. This will still cause session cross
+		// pollution if a snapshot from another instance is loaded here.
+		return current && current.account.id === session.account.id;
+	}));
+	await writeSubscriptions(snapshot.subscriptions);
+	await writeSchedule(snapshot.schedule);
+	await sendRedirect(event, "/");
+})

server/api/admin/delete-schedule.post.ts

@@ -0,0 +1,11 @@
+import { writeSchedule } from "~/server/database";
+import type { ApiSchedule } from "~/shared/types/api";
+
+export default defineEventHandler(async (event) => {
+	await requireServerSessionWithAdmin(event);
+	const schedule: ApiSchedule = {
+		id: 111,
+		updatedAt: new Date().toISOString(),
+	};
+	await writeSchedule(schedule);
+})

server/database.ts

@@ -1,6 +1,5 @@
 import { readFile, unlink, writeFile } from "node:fs/promises";
 import type { ApiSchedule, ApiSubscription, ApiUserType } from "~/shared/types/api";
-import { generateDemoSchedule, generateDemoAccounts } from "~/server/generate-demo-schedule";
 import type { Id } from "~/shared/types/common";
 
 export interface ServerSession {
@@ -65,7 +64,10 @@ async function readJson<T>(filePath: string, fallback: T) {
 }
 
 export async function readSchedule() {
-	return readJson(schedulePath, generateDemoSchedule);
+	return readJson(schedulePath, (): ApiSchedule => ({
+		id: 111,
+		updatedAt: new Date().toISOString(),
+	}));
 }
 
 export async function writeSchedule(schedule: ApiSchedule) {
@@ -85,6 +87,14 @@ export async function writeSubscriptions(subscriptions: ApiSubscription[]) {
 	await writeFile(subscriptionsPath, JSON.stringify(subscriptions, undefined, "\t") + "\n", "utf-8");
 }
 
+export async function readNextUserId() {
+	return await readJson(nextUserIdPath, 0);
+}
+
+export async function writeNextUserId(nextId: number) {
+	await writeFile(nextUserIdPath, String(nextId), "utf-8");
+}
+
 export async function nextUserId() {
 	let nextId = await readJson(nextUserIdPath, 0);
 	if (nextId === 0) {
@@ -95,13 +105,21 @@ export async function nextUserId() {
 }
 
 export async function readUsers() {
-	return await readJson(usersPath, generateDemoAccounts as () => ServerUser[]);
+	return await readJson(usersPath, (): ServerUser[] => []);
 }
 
 export async function writeUsers(users: ServerUser[]) {
 	await writeFile(usersPath, JSON.stringify(users, undefined, "\t") + "\n", "utf-8");
 }
 
+export async function readNextSessionId() {
+	return await readJson(nextSessionIdPath, 0);
+}
+
+export async function writeNextSessionId(nextId: number) {
+	await writeFile(nextSessionIdPath, String(nextId), "utf-8");
+}
+
 export async function nextSessionId() {
 	const nextId = await readJson(nextSessionIdPath, 0);
 	await writeFile(nextSessionIdPath, String(nextId + 1), "utf-8");