Aim a bulk email at one day of a listing booked by the day

specs/attendees/writing-to-the-people-who-booked.feature

@@ -107,3 +107,42 @@ Feature: An owner writes to the people who booked
       Given the owner has an email provider of their own
       And 1 person has booked onto "the Gig"
       Then "the Gig" offers a way to write to the people who booked
+
+  @rule:attendees.a-message-can-be-aimed-at-one-day
+  Rule: A message can be aimed at one day of a listing booked by the day
+    A listing booked by the day holds several days' worth of people, and news
+    about one of those days is not news for the rest. The owner can aim a
+    message at a single day, and everyone the site writes to is somebody that
+    day belongs to. Aiming at the listing itself still reaches all of them, so
+    the day is an extra way to choose rather than the only one.
+
+    @case:writing.one-day-hears-and-the-others-do-not
+    Scenario: The owner writes to one day
+      Given the owner has an email provider of their own
+      And "Rachel" has booked onto "the Course" for day 1
+      And "Marco" has booked onto "the Course" for day 8
+      When the owner writes to "the Course" on day 1 saying "We are in the small hall tonight."
+      Then the owner is shown that it would reach 1 person
+      When the owner sends it
+      Then it was written to "Rachel"
+      And nothing was written to "Marco"
+
+    @case:writing.the-whole-listing-still-reaches-every-day
+    Scenario: The owner writes to the listing rather than to a day
+      Given the owner has an email provider of their own
+      And "Rachel" has booked onto "the Course" for day 1
+      And "Marco" has booked onto "the Course" for day 8
+      When the owner writes to "the Course" saying "The term ends a week early."
+      Then the owner is shown that it would reach 2 people
+      When the owner sends it
+      Then it was written to "Rachel"
+      And it was written to "Marco"
+
+    @case:writing.a-stay-hears-about-every-day-it-covers
+    Scenario: A booking covering several days hears about each of them
+      Given the owner has an email provider of their own
+      And "Priya" has booked onto "the Hall" from day 1 for 3 days
+      When the owner writes to "the Hall" on day 3 saying "The car park is closed."
+      Then the owner is shown that it would reach 1 person
+      When the owner sends it
+      Then it was written to "Priya"

src/features/admin/listing-page-data.ts

@@ -16,7 +16,6 @@ import { listingMoneyTotals } from "#shared/accounting/listing-money-totals.ts";
 import { emptyRange } from "#shared/accounting/range.ts";
 import { resolveRecipientEmails } from "#shared/bulk-email.ts";
 import { getEffectiveDomain } from "#shared/config.ts";
-import { formatDateLabel } from "#shared/dates.ts";
 import {
   type ActivityLogEntry,
   getListingActivityLog,
@@ -60,6 +59,7 @@ import { ListingRosterPanel } from "#templates/admin/listings/roster.tsx";
 import type { AttendeeFilter } from "#templates/admin/listings/types.ts";
 import type { TableQuestionData } from "#templates/attendee-table/types.ts";
 import {
+  dateOptionsFor,
   filterByDate,
   loadGroupContext,
   loadListingQuestionData,
@@ -154,19 +154,6 @@ const loadDecryptedListingAttendees = async (
   return decryptAttendees(attendeesRaw, privateKey);
 };
 
-/** The distinct booking dates present on a daily listing, ascending, as the
- *  roster's date-picker options; empty for a non-daily listing. */
-const availableDatesFor = (
-  listing: ListingWithCount,
-  attendees: Attendee[],
-): { value: string; label: string }[] => {
-  if (listing.listing_type !== "daily") return [];
-  const dates = [
-    ...new Set(attendees.map((a) => a.date).filter((d): d is string => !!d)),
-  ].sort((a, b) => a.localeCompare(b));
-  return dates.map((value) => ({ label: formatDateLabel(value), value }));
-};
-
 /** The Overview's answer summary needs only the questions and each attendee's
  *  chosen answer ids (counted per option) — never the free-text answers. So it
  *  reads the choice ids scoped to the listing in SQL, decrypting nothing.
@@ -278,7 +265,7 @@ export const loadListingRosterPanel = async (
     activeFilter,
     allowedDomain: getEffectiveDomain(),
     attendees: filteredByDate,
-    availableDates: availableDatesFor(listing, attendees),
+    availableDates: dateOptionsFor(listing, attendees),
     childNames: (childrenLinks.listingsByKey.get(listing.id) ?? []).map(
       (child) => child.name,
     ),

src/features/admin/listing-page.ts

@@ -27,7 +27,7 @@ import {
 import { panelTab, writeFormTab } from "#routes/admin/entity-write-tab.ts";
 import { type AuthSession, requireContentOr } from "#routes/auth.ts";
 import type { AdminFeatureKey } from "#shared/admin-features.ts";
-import { targetQuery } from "#shared/bulk-email-targets.ts";
+import { targetQuery } from "#shared/bulk-email-targets/registry.ts";
 import { settings } from "#shared/db/settings.ts";
 import { isStorageEnabled } from "#shared/storage.ts";
 import {

src/features/admin/listings-view.ts

@@ -17,7 +17,7 @@ import {
 } from "#fp";
 import { getDateFilter } from "#routes/admin/actions.ts";
 import type { AuthSession } from "#routes/auth.ts";
-import { formatDateLabel } from "#shared/dates.ts";
+import { coveredDays, formatDateLabel } from "#shared/dates.ts";
 import { getGroupRemainingByGroupId } from "#shared/db/attendees/capacity/groups.ts";
 import { getGroupsByIds, listingGroups } from "#shared/db/groups.ts";
 import {
@@ -28,26 +28,39 @@ import { getQuestionsForListing } from "#shared/db/questions/queries.ts";
 import type { ResponseHandler } from "#shared/response-steps.ts";
 import { requireRequestPrivateKey } from "#shared/session-private-key.ts";
 import type { Attendee, ListingWithCount } from "#shared/types.ts";
-import type { GroupContext } from "#templates/admin/listings/types.ts";
+import type {
+  DateOption,
+  GroupContext,
+} from "#templates/admin/listings/types.ts";
 
-/** Filter attendees by date for daily listings */
+/** Keep the attendees a chosen day belongs to. A booking counts for every day
+ * it covers, so day 2 of a three-day stay lists that stay. */
 export const filterByDate = (
   attendees: Attendee[],
   date: string | null,
 ): Attendee[] =>
-  date ? filter((a: Attendee) => a.date === date)(attendees) : attendees;
+  date
+    ? filter((a: Attendee) => coveredDays(a.date, a.end_date).includes(date))(
+        attendees,
+      )
+    : attendees;
 
-/** Collect unique dates from attendees, sorted ascending */
-const getUniqueDates: (
-  attendees: Attendee[],
-) => { value: string; label: string }[] = pipe(
-  map((a: Attendee) => a.date),
-  (dates) => compact(dates),
+const getUniqueDates: (attendees: Attendee[]) => DateOption[] = pipe(
+  (attendees: Attendee[]) =>
+    attendees.flatMap((a: Attendee) => coveredDays(a.date, a.end_date)),
+  (dates: string[]) => compact(dates),
   (dates) => unique(dates),
   sort((a, b) => a.localeCompare(b)),
-  map((d) => ({ label: formatDateLabel(d), value: d })),
+  map((d: string) => ({ label: formatDateLabel(d), value: d })),
 );
 
+/** The roster's date-picker options; empty for a listing not booked by the day. */
+export const dateOptionsFor = (
+  listing: ListingWithCount,
+  attendees: Attendee[],
+): DateOption[] =>
+  listing.listing_type === "daily" ? getUniqueDates(attendees) : [];
+
 /** Get date filter and filtered attendees for daily listings */
 const applyDateFilter = (
   listing: ListingWithCount,
@@ -56,10 +69,8 @@ const applyDateFilter = (
 ) => {
   const dateFilter =
     listing.listing_type === "daily" ? getDateFilter(request) : null;
-  const availableDates =
-    listing.listing_type === "daily" ? getUniqueDates(attendees) : [];
   return {
-    availableDates,
+    availableDates: dateOptionsFor(listing, attendees),
     dateFilter,
     filteredByDate: filterByDate(attendees, dateFilter),
   };

src/locales/en/listings-table.json

@@ -17,6 +17,7 @@
   "listings_table.booking_qr": "Booking QR",
   "listings_table.no_email_attendees": "No attendees have an email address",
   "listings_table.export_csv": "Export CSV",
+  "listings_table.email_this_date": "Email this date's attendees",
   "listings_table.column.name.label": "Name",
   "listings_table.column.name.header": "Listing name",
   "listings_table.column.name.description": "Shows the listing name and image. The name links to the listing details.",