New scheduling UI!

src/lib/server/auth.test.ts

@@ -1,4 +1,4 @@
-import type { RequestEvent } from '@sveltejs/kit';
+import type { Cookies } from '@sveltejs/kit';
 import { eq } from 'drizzle-orm';
 import { testDb as db } from '$lib/server/db/test';
 import * as table from '$lib/server/db/schema';
@@ -64,15 +64,15 @@ export async function invalidateSession(sessionId: string) {
 	await db.delete(table.session).where(eq(table.session.id, sessionId));
 }
 
-export function setSessionTokenCookie(event: RequestEvent, token: string, expiresAt: Date) {
-	event.cookies.set(sessionCookieName, token, {
+export function setSessionTokenCookie({ cookies }: { cookies: Cookies }, token: string, expiresAt: Date) {
+	cookies.set(sessionCookieName, token, {
 		expires: expiresAt,
 		path: '/'
 	});
 }
 
-export function deleteSessionTokenCookie(event: RequestEvent) {
-	event.cookies.delete(sessionCookieName, {
+export function deleteSessionTokenCookie({ cookies }: { cookies: Cookies }) {
+	cookies.delete(sessionCookieName, {
 		path: '/'
 	});
 }

src/lib/server/auth.ts

@@ -1,4 +1,4 @@
-import type { RequestEvent } from '@sveltejs/kit';
+import type { Cookies, RequestEvent } from '@sveltejs/kit';
 import { eq } from 'drizzle-orm';
 import { db } from '$lib/server/db';
 import * as table from '$lib/server/db/schema';
@@ -64,15 +64,15 @@ export async function invalidateSession(sessionId: string) {
 	await db.delete(table.session).where(eq(table.session.id, sessionId));
 }
 
-export function setSessionTokenCookie(event: RequestEvent, token: string, expiresAt: Date) {
-	event.cookies.set(sessionCookieName, token, {
+export function setSessionTokenCookie({ cookies }: { cookies: Cookies }, token: string, expiresAt: Date) {
+	cookies.set(sessionCookieName, token, {
 		expires: expiresAt,
 		path: '/'
 	});
 }
 
-export function deleteSessionTokenCookie(event: RequestEvent) {
-	event.cookies.delete(sessionCookieName, {
+export function deleteSessionTokenCookie({ cookies }: { cookies: Cookies }) {
+	cookies.delete(sessionCookieName, {
 		path: '/'
 	});
 }

src/lib/server/bible-api.ts

@@ -31,3 +31,22 @@ export async function fetchRandomVerse(): Promise<ApiVerse> {
 		verseText
 	};
 }
+
+/**
+ * Like fetchRandomVerse, but re-rolls until the picked book is not in
+ * `avoidBookIds` (the no-back-to-back neighbors for lazy gap-fill).
+ * 66 books with ≤2 excluded gives ~97% success per try; capped at 20 tries
+ * before accepting whatever was last drawn (spec: "Lazy Gap-Fill").
+ */
+export async function fetchRandomVerseAvoiding(
+	avoidBookIds: string[] = []
+): Promise<ApiVerse> {
+	const avoid = new Set(avoidBookIds.filter(Boolean));
+	let last: ApiVerse | null = null;
+	for (let i = 0; i < 20; i++) {
+		const v = await fetchRandomVerse();
+		last = v;
+		if (!avoid.has(v.bookId)) return v;
+	}
+	return last as ApiVerse;
+}

src/lib/server/daily-verse.ts

@@ -1,9 +1,16 @@
 import { db } from '$lib/server/db';
 import { dailyVerses } from '$lib/server/db/schema';
 import { eq, sql } from 'drizzle-orm';
-import { fetchRandomVerse } from '$lib/server/bible-api';
+import { fetchRandomVerse, fetchRandomVerseAvoiding } from '$lib/server/bible-api';
 import type { DailyVerse } from '$lib/server/db/schema';
 
+/** Add `n` days to a YYYY-MM-DD string using pure UTC arithmetic. */
+function addDays(dateStr: string, n: number): string {
+	const d = new Date(dateStr + 'T00:00:00Z');
+	d.setUTCDate(d.getUTCDate() + n);
+	return d.toISOString().slice(0, 10);
+}
+
 export async function getVerseForDate(dateStr: string): Promise<DailyVerse> {
 	// Validate date format (YYYY-MM-DD)
 	if (!/^\d{4}-\d{2}-\d{2}$/.test(dateStr)) {
@@ -16,8 +23,28 @@ export async function getVerseForDate(dateStr: string): Promise<DailyVerse> {
 		return existing[0];
 	}
 
-	// Otherwise get a new random verse for this date
-	const apiVerse = await fetchRandomVerse();
+	// Otherwise get a new random verse for this date. Gap-fill is extended to
+	// respect the no-back-to-back rule: the random verse's book must differ from
+	// any committed neighbor (D-1 / D+1). This preserves the global invariant
+	// that no two consecutive calendar days ever feature the same book
+	// (spec: "Lazy Gap-Fill").
+	const [prev] = await db
+		.select({ bookId: dailyVerses.bookId })
+		.from(dailyVerses)
+		.where(eq(dailyVerses.date, addDays(dateStr, -1)))
+		.limit(1);
+	const [next] = await db
+		.select({ bookId: dailyVerses.bookId })
+		.from(dailyVerses)
+		.where(eq(dailyVerses.date, addDays(dateStr, 1)))
+		.limit(1);
+
+	const avoid = [prev?.bookId, next?.bookId].filter((b): b is string => !!b);
+	const apiVerse =
+		avoid.length > 0
+			? await fetchRandomVerseAvoiding(avoid)
+			: await fetchRandomVerse();
+
 	const createdAt = sql`${Math.floor(Date.now() / 1000)}`;
 
 	const newVerse: Omit<DailyVerse, 'createdAt'> = {

src/lib/server/verse-submission.ts

@@ -0,0 +1,293 @@
+import { db as defaultDb } from '$lib/server/db';
+import { dailyVerses, verseSubmissions } from '$lib/server/db/schema';
+import { eq, desc, sql } from 'drizzle-orm';
+import { getBookById } from '$lib/server/bible';
+
+// Drizzle instance type alias (the production db or the test db).
+export type Db = typeof defaultDb;
+import {
+	composeVerseWindow,
+	formatWindowReference,
+	getChapterCount,
+	getVerseCount
+} from '$lib/server/xml-bible';
+
+// Server-side constants for the community-verse-submission feature
+// (spec: "Rate Limiting & Cooldown", "Scheduling Algorithm").
+const DAY_MS = 1000 * 60 * 60 * 24;
+export const COOLDOWN_MS = 7 * DAY_MS;
+export const REPEAT_WINDOW_DAYS = 60;
+const MAX_SCHEDULE_RETRIES = 5;
+// Safety cap on the day-by-day forward scan. 10k days (~27 years) is well
+// beyond any realistic calendar density; prevents an accidental infinite loop.
+const MAX_SCAN_DAYS = 10_000;
+
+export interface SubmissionInput {
+	bookId: string;
+	chapter: number;
+	verse: number;
+}
+
+export interface ScheduleResult {
+	scheduledDate: string;
+	reference: string;
+	windowText: string;
+	bookId: string;
+}
+
+/** Add `n` days to a YYYY-MM-DD string using pure UTC arithmetic. */
+export function addDays(dateStr: string, n: number): string {
+	const d = new Date(dateStr + 'T00:00:00Z');
+	d.setUTCDate(d.getUTCDate() + n);
+	return d.toISOString().slice(0, 10);
+}
+
+/** Whole-day difference (b - a) between two YYYY-MM-DD strings, UTC. */
+export function dayDiff(a: string, b: string): number {
+	const ta = new Date(a + 'T00:00:00Z').getTime();
+	const tb = new Date(b + 'T00:00:00Z').getTime();
+	return Math.round((tb - ta) / DAY_MS);
+}
+
+/** Current server UTC date as YYYY-MM-DD. */
+export function todayUtcStr(): string {
+	return new Date().toISOString().slice(0, 10);
+}
+
+/**
+ * The canonical identity of a 3-verse window, used by the 60-day repeat rule.
+ * Combines bookId + formatted reference so identical windows collide regardless
+ * of how the underlying row was produced (submission vs. random gap-fill).
+ */
+function windowRef(bookId: string, reference: string): string {
+	return `${bookId}|${reference}`;
+}
+
+/** Is this a SQLite unique-constraint violation (used for retry-on-conflict)? */
+export function isUniqueConstraintError(err: unknown): boolean {
+	const e = err as { code?: string; message?: string } | null;
+	return !!e && (
+		e.code === 'SQLITE_CONSTRAINT_UNIQUE' ||
+		e.code === 'SQLITE_CONSTRAINT' ||
+		!!(e.message && /UNIQUE/i.test(e.message))
+	);
+}
+
+export interface CooldownState {
+	/** True if the user submitted within the last 7 days. */
+	onCooldown: boolean;
+	/** Server UTC millis when the cooldown expires, or null. */
+	cooldownEndsAt: number | null;
+}
+
+/** Compute the rolling 7-day cooldown state for a user (server UTC). */
+export async function getCooldownState(
+	db: Db,
+	userId: string,
+	now: number = Date.now()
+): Promise<CooldownState> {
+	const [last] = await db
+		.select({ submittedAt: verseSubmissions.submittedAt })
+		.from(verseSubmissions)
+		.where(eq(verseSubmissions.userId, userId))
+		.orderBy(desc(verseSubmissions.submittedAt))
+		.limit(1);
+
+	if (!last) {
+		return { onCooldown: false, cooldownEndsAt: null };
+	}
+
+	const cooldownEndsAt = last.submittedAt + COOLDOWN_MS;
+	if (now < cooldownEndsAt) {
+		return { onCooldown: true, cooldownEndsAt };
+	}
+	return { onCooldown: false, cooldownEndsAt: null };
+}
+
+/** Structural validation of a user-supplied (bookId, chapter, verse) selection. */
+export function validateSelection(input: SubmissionInput): string | null {
+	const book = getBookById(input.bookId);
+	if (!book) return 'Unknown bookId';
+
+	if (!Number.isInteger(input.chapter) || input.chapter < 1) {
+		return 'chapter must be a positive integer';
+	}
+	const chapterCount = getChapterCount(book.order);
+	if (input.chapter > chapterCount) {
+		return `chapter out of range (1-${chapterCount})`;
+	}
+
+	if (!Number.isInteger(input.verse) || input.verse < 1) {
+		return 'verse must be a positive integer';
+	}
+	const verseCount = getVerseCount(book.order, input.chapter);
+	if (input.verse > verseCount) {
+		return `verse out of range (1-${verseCount})`;
+	}
+
+	return null;
+}
+
+interface LoadedCalendar {
+	byDate: Map<string, { bookId: string; windowRef: string }>;
+	datesByWindowRef: Map<string, string[]>;
+}
+
+/** Load every committed daily_verses row into in-memory indexes for the scan. */
+async function loadCalendar(db: Db): Promise<LoadedCalendar> {
+	const rows = await db
+		.select({
+			date: dailyVerses.date,
+			bookId: dailyVerses.bookId,
+			reference: dailyVerses.reference
+		})
+		.from(dailyVerses);
+
+	const byDate = new Map<string, { bookId: string; windowRef: string }>();
+	const datesByWindowRef = new Map<string, string[]>();
+
+	for (const r of rows) {
+		const wr = windowRef(r.bookId, r.reference);
+		byDate.set(r.date, { bookId: r.bookId, windowRef: wr });
+		const arr = datesByWindowRef.get(wr);
+		if (arr) arr.push(r.date);
+		else datesByWindowRef.set(wr, [r.date]);
+	}
+
+	return { byDate, datesByWindowRef };
+}
+
+/**
+ * Find the earliest valid candidate date `D` (scanning forward from tomorrow,
+ * server UTC) for a submission with the given book + window identity.
+ *
+ * Validity (spec "Scheduling Algorithm"):
+ *  1. Empty:            no daily_verses row at D.
+ *  2. No back-to-back:  D-1 (if committed) has a different book.
+ *  3. No back-to-back:  D+1 (if committed) has a different book.
+ *  4. 60-day repeat:    no identical window within [D-60, D+60] inclusive.
+ */
+async function findCandidateDate(
+	db: Db,
+	bookId: string,
+	submissionWindowRef: string,
+	opts?: { startFrom?: string; today?: string }
+): Promise<string | null> {
+	const { byDate, datesByWindowRef } = await loadCalendar(db);
+
+	let cursor = opts?.startFrom ?? addDays(opts?.today ?? todayUtcStr(), 1);
+	for (let i = 0; i < MAX_SCAN_DAYS; i++) {
+		// Rule 1: must be empty.
+		if (!byDate.has(cursor)) {
+			// Rules 2 & 3: no back-to-back with committed neighbors.
+			const prev = byDate.get(addDays(cursor, -1));
+			const next = byDate.get(addDays(cursor, 1));
+			const backToBack =
+				(!!prev && prev.bookId === bookId) ||
+				(!!next && next.bookId === bookId);
+
+			if (!backToBack) {
+				// Rule 4: 60-day repeat distance for the identical window.
+				const sameWindowDates = datesByWindowRef.get(submissionWindowRef) ?? [];
+				const tooClose = sameWindowDates.some(
+					(d) => Math.abs(dayDiff(d, cursor)) <= REPEAT_WINDOW_DAYS
+				);
+				if (!tooClose) {
+					return cursor;
+				}
+			}
+		}
+		cursor = addDays(cursor, 1);
+	}
+
+	return null;
+}
+
+/**
+ * Run the scheduling scan and write the daily_verses + verse_submissions rows
+ * in a transaction. On a unique-constraint conflict (concurrent submission
+ * picked the same date), re-run the scan from the next day; retry up to a
+ * small bound.
+ */
+export async function scheduleSubmission(
+	db: Db,
+	input: SubmissionInput,
+	userId: string,
+	now: number = Date.now(),
+	opts?: { today?: string }
+): Promise<ScheduleResult> {
+	const book = getBookById(input.bookId);
+	if (!book) throw new Error('Invalid bookId');
+
+	const window = composeVerseWindow(book.order, input.chapter, input.verse);
+	if (!window) throw new Error('Invalid chapter/verse for this book');
+
+	const reference = formatWindowReference(
+		window.bookName,
+		window.startChapter,
+		window.startVerse,
+		window.endChapter,
+		window.endVerse
+	);
+	const windowText = window.verses.join(' ');
+	const submissionWindowRef = windowRef(book.id, reference);
+	let lastCandidate = '';
+
+	for (let attempt = 0; attempt < MAX_SCHEDULE_RETRIES; attempt++) {
+		// Re-compute the candidate each attempt — a concurrent submission may
+		// have claimed the previous candidate between scan and insert. After a
+		// conflict, re-scan from the day *after* the contested candidate.
+		const candidate = await findCandidateDate(
+			db,
+			book.id,
+			submissionWindowRef,
+			attempt === 0
+				? { today: opts?.today }
+				: { startFrom: addDays(lastCandidate, 1) }
+		);
+		if (!candidate) {
+			throw new Error('No valid candidate date found within the scan window');
+		}
+		lastCandidate = candidate;
+
+		try {
+			db.transaction((tx) => {
+				tx.insert(dailyVerses)
+					.values({
+						id: Bun.randomUUIDv7(),
+						date: candidate,
+						bookId: book.id,
+						verseText: windowText,
+						reference,
+						createdAt: sql`${Math.floor(now / 1000)}`
+					})
+					.run();
+				tx.insert(verseSubmissions)
+					.values({
+						id: Bun.randomUUIDv7(),
+						userId,
+						scheduledDate: candidate,
+						selectedBookId: input.bookId,
+						selectedChapter: input.chapter,
+						selectedVerse: input.verse,
+						submittedAt: now
+					})
+					.run();
+			});
+
+			return {
+				scheduledDate: candidate,
+				reference,
+				windowText,
+				bookId: book.id
+			};
+		} catch (err) {
+			if (isUniqueConstraintError(err)) {
+				continue; // retry — re-scan from tomorrow
+			}
+			throw err;
+		}
+	}
+
+	throw new Error('Failed to schedule submission after retries');
+}