feat: implement gap detection algorithm

Author: stampaaaron

apps/frontend/src/routes/_auth/questionnaire/_questionnaire/$id/entries.tsx

@@ -1,11 +1,14 @@
-import { Button, Group, Stack, notifications } from "@quassel/ui";
+import { Button, Group, Stack, notifications, useForm } from "@quassel/ui";
 import { createFileRoute, Link, useNavigate } from "@tanstack/react-router";
 import { i18n } from "../../../../../stores/i18n";
 import { useStore } from "@nanostores/react";
 import { $api } from "../../../../../stores/api";
 import { EntryFormValues } from "../../../../../components/questionnaire/calendar/EntryForm";
 import { useQueryClient } from "@tanstack/react-query";
 import { EntryCalendar } from "../../../../../components/questionnaire/calendar/EntryCalendar";
+import { useEffect } from "react";
+import { components } from "../../../../../api.gen";
+import { resolveGaps } from "../../../../../utils/entry";
 
 const messages = i18n("questionnaireEntries", {
   formAction: "Continue",
@@ -23,6 +26,20 @@ function QuestionnaireEntries() {
 
   const c = useQueryClient();
 
+  const f = useForm<{ entries: components["schemas"]["QuestionnaireEntryDto"][] }>({
+    initialValues: {
+      entries: [],
+    },
+    validate: {
+      entries: (value) => {
+        const gaps = resolveGaps(value);
+        console.log(gaps);
+
+        return !!gaps.length;
+      },
+    },
+  });
+
   const createMutation = $api.useMutation("post", "/entries");
   const updateMutation = $api.useMutation("patch", "/entries/{id}");
   const deleteMutation = $api.useMutation("delete", "/entries/{id}");
@@ -80,9 +97,13 @@ function QuestionnaireEntries() {
     n({ to: "/questionnaire/$id/remarks", params: p });
   };
 
+  useEffect(() => {
+    f.setValues({ entries: questionnaire.entries });
+  }, [questionnaire]);
+
   return (
     <>
-      <form onSubmit={handleSubmit}>
+      <form onSubmit={f.onSubmit(handleSubmit)}>
         <Stack>
           <EntryCalendar
             entries={questionnaire.entries ?? []}

apps/frontend/src/utils/entry.ts

@@ -0,0 +1,28 @@
+import { components } from "../api.gen";
+
+type Entry = components["schemas"]["QuestionnaireEntryDto"];
+
+const groupByWeekday = (entries: Entry[]) =>
+  entries.reduce<Entry[][]>((acc, cur) => {
+    acc[cur.weekday] = [...(acc[cur.weekday] ?? []), cur];
+    return acc;
+  }, []);
+
+export const resolveGaps = (entries: Entry[]) => groupByWeekday(entries).map(resolveGapsInDay);
+
+// inspired by: https://cs.stackexchange.com/questions/133276/algorithm-to-compute-the-gaps-between-a-set-of-intervals
+const resolveGapsInDay = (entriesOfSameDay: Entry[]) => {
+  const entriesSortedByStart = entriesOfSameDay.toSorted((a, b) => a.startedAt.localeCompare(b.startedAt));
+
+  const gaps: [string, string][] = [];
+  let lastCoveredTime = entriesSortedByStart[0]?.endedAt;
+
+  for (const entry of entriesSortedByStart) {
+    if (entry.startedAt > lastCoveredTime) {
+      gaps.push([lastCoveredTime, entry.startedAt]);
+    }
+    lastCoveredTime = lastCoveredTime > entry.endedAt ? lastCoveredTime : entry.endedAt;
+  }
+
+  return gaps;
+};