Group tournaments into a single map marker based on position & date (#105)

app/[lang]/tournois/page.tsx

@@ -2,6 +2,8 @@ import clientPromise from "@/lib/mongodb";
 
 import { errorLog } from "@/utils/logger";
 import { Tournament, TimeControl } from "@/types";
+import { groupBy } from "lodash";
+import { parse, differenceInDays, isSameDay } from "date-fns";
 
 import TournamentsDisplay from "./TournamentsDisplay";
 import { ObjectId } from "mongodb";
@@ -54,13 +56,61 @@ const getTournaments = async () => {
       ])
       .toArray();
 
-    return data.map<Tournament>((t) => ({
-      ...t,
-      _id: t._id.toString(),
-      timeControl: tcMap[t.time_control] ?? TimeControl.Other,
-      latLng: { lat: t.coordinates[0], lng: t.coordinates[1] },
-      norm: t.norm_tournament,
-    }));
+    // Group the tournaments by their location
+    const groupedByLocation = groupBy(
+      data,
+      (t) => `${t.coordinates[0]}_${t.coordinates[1]}`,
+    );
+
+    // For each location, create an array of arrays of contiguous dates for this location
+    const dateRangesByLocation: Record<string, Date[][]> = {};
+    for (const location in groupedByLocation) {
+      const tournaments = groupedByLocation[location];
+
+      // Note that this works since the tournaments are sorted by date
+      const dateRanges = tournaments.reduce<Date[][]>(
+        (acc, tournament) => {
+          const group = acc[acc.length - 1];
+          const date = parse(tournament.date, "dd/MM/yyyy", new Date());
+          const diff = differenceInDays(date, group[group.length - 1] ?? date);
+          if (diff > 1) {
+            acc.push([date]);
+          } else if (group.length === 0 || diff === 1) {
+            group.push(date);
+          }
+          return acc;
+        },
+        [[]],
+      );
+
+      dateRangesByLocation[location] = dateRanges;
+    }
+
+    return data.map<Tournament>((t) => {
+      const location = `${t.coordinates[0]}_${t.coordinates[1]}`;
+      const date = parse(t.date, "dd/MM/yyyy", new Date());
+      const dateRanges = dateRangesByLocation[location];
+      const rangeIndex = dateRanges.findIndex((ranges) =>
+        ranges.some((d) => isSameDay(d, date)),
+      );
+
+      // We place each tournament into a group based on location and date, so that
+      // we can display a single map marker.
+      const groupId = `${location}_${rangeIndex}`;
+
+      return {
+        id: t._id.toString(),
+        groupId,
+        tournament: t.tournament,
+        town: t.town,
+        department: t.department,
+        date: t.date,
+        url: t.url,
+        timeControl: tcMap[t.time_control] ?? TimeControl.Other,
+        latLng: { lat: t.coordinates[0], lng: t.coordinates[1] },
+        norm: t.norm_tournament,
+      };
+    });
   } catch (error) {
     errorLog(error);
     throw new Error("Error fetching tournament data");