organize events by months, weeks and days and print a calendar view

web/src/lib/event.ts

@@ -1,7 +1,23 @@
+import {
+  compareAsc,
+  getYear,
+  getMonth,
+  getWeek,
+  getDate,
+  endOfWeek,
+  startOfWeek,
+  eachDayOfInterval,
+  addWeeks,
+} from "date-fns";
+import { toLocalTime, formatDate } from "./date";
 import { graphql } from "@/gql";
 import { EventFragment, EventOccurrence } from "@/gql/graphql";
 
-export type { EventFragment } from "@/gql/graphql"
+export type { EventFragment } from "@/gql/graphql";
+
+export type SingularEvent = EventFragment & {
+  occurrence: EventOccurrence;
+};
 
 const EventFragmentDefinition = graphql(`
   fragment Event on EventPage {
@@ -55,10 +71,6 @@ export const allEventsQuery = graphql(`
   }
 `);
 
-export type SingularEvent = EventFragment & {
-  occurrence: EventOccurrence;
-};
-
 export function getSingularEvents(events: EventFragment[]) {
   return events
     .map((event) => {
@@ -77,3 +89,59 @@ export function getSingularEvents(events: EventFragment[]) {
 function isDefined<T>(val: T | undefined | null): val is T {
   return val !== undefined && val !== null;
 }
+
+interface EventsByDate {
+  [yearMonth: string]: {
+    [week: number]: {
+      [day: number]: SingularEvent[];
+    };
+  };
+}
+
+export function organizeEventsByDate(events: SingularEvent[]): EventsByDate {
+  const sortedEvents = events.sort((a, b) =>
+    compareAsc(new Date(a.occurrence.start), new Date(b.occurrence.start))
+  );
+
+  const eventsByDate: EventsByDate = {};
+
+  const minDate = new Date(sortedEvents[0]?.occurrence.start);
+  const maxDate = new Date(
+    sortedEvents[sortedEvents.length - 1]?.occurrence.start
+  );
+
+  let currentDate = startOfWeek(minDate, { weekStartsOn: 1 });
+  while (currentDate <= maxDate) {
+    const yearMonth = formatDate(currentDate, "yyyy-MM");
+    const week = formatDate(currentDate, "w");
+    const daysOfWeek = eachDayOfInterval({
+      start: currentDate,
+      end: endOfWeek(currentDate, { weekStartsOn: 1 }),
+    });
+
+    if (!eventsByDate[yearMonth]) {
+      eventsByDate[yearMonth] = {};
+    }
+    if (!eventsByDate[yearMonth][week]) {
+      eventsByDate[yearMonth][week] = {};
+    }
+    daysOfWeek.forEach((day) => {
+      const formattedDay = formatDate(day, "yyyy-MM-dd");
+      if (!eventsByDate[yearMonth][week][formattedDay]) {
+        eventsByDate[yearMonth][week][formattedDay] = [];
+      }
+    });
+
+    currentDate = addWeeks(currentDate, 1);
+  }
+
+  sortedEvents.forEach((event) => {
+    const start = toLocalTime(event.occurrence.start);
+    const yearMonth = formatDate(start, "yyyy-MM");
+    const week = formatDate(start, "w");
+    const day = formatDate(start, "yyyy-MM-dd");
+    eventsByDate[yearMonth][week][day].push(event);
+  });
+
+  return eventsByDate;
+}