feat(plan): resolveGrid for batch cell resolution

src/services/plan.service.ts

@@ -96,3 +96,102 @@ export async function resolveCell(
     rangeTo: entry.date_to.toISOString().slice(0, 10),
   };
 }
+
+/**
+ * Compute the effective plan cell for every (userId, date) in the
+ * given range. Returns a 2D map: cells[userId][dateStr] = ResolvedCell | null.
+ *
+ * Implementation: load all entries and overrides for the range in two
+ * queries, then iterate the dates and resolve each cell in O(1) per
+ * (user, date). This avoids N+1 calls to resolveCell.
+ */
+export async function resolveGrid(
+  userIds: number[],
+  dateFromStr: string,
+  dateToStr: string,
+): Promise<Record<number, Record<string, ResolvedCell | null>>> {
+  const dateFrom = new Date(dateFromStr);
+  const dateTo = new Date(dateToStr);
+
+  const [entries, overrides] = await Promise.all([
+    prisma.work_plan_entries.findMany({
+      where: {
+        user_id: { in: userIds },
+        is_deleted: false,
+        date_from: { lte: dateTo },
+        date_to: { gte: dateFrom },
+      },
+      orderBy: { created_at: "desc" },
+    }),
+    prisma.work_plan_overrides.findMany({
+      where: {
+        user_id: { in: userIds },
+        is_deleted: false,
+        shift_date: { gte: dateFrom, lte: dateTo },
+      },
+    }),
+  ]);
+
+  // Build a date list (inclusive)
+  const dates: string[] = [];
+  for (
+    let d = new Date(dateFrom);
+    d <= dateTo;
+    d.setUTCDate(d.getUTCDate() + 1)
+  ) {
+    dates.push(d.toISOString().slice(0, 10));
+  }
+
+  const result: Record<number, Record<string, ResolvedCell | null>> = {};
+  for (const uid of userIds) {
+    result[uid] = {};
+    for (const dateStr of dates) {
+      // Override first
+      const override = overrides.find(
+        (o) =>
+          o.user_id === uid &&
+          o.shift_date.toISOString().slice(0, 10) === dateStr,
+      );
+      if (override) {
+        result[uid][dateStr] = {
+          source: "override",
+          entryId: null,
+          overrideId: override.id,
+          user_id: override.user_id,
+          shift_date: dateStr,
+          project_id: override.project_id,
+          category: override.category,
+          note: override.note,
+          rangeFrom: null,
+          rangeTo: null,
+        };
+        continue;
+      }
+      // First (latest by created_at) matching entry
+      const entry = entries.find(
+        (e) =>
+          e.user_id === uid &&
+          e.date_from <= new Date(dateStr) &&
+          e.date_to >= new Date(dateStr),
+      );
+      if (entry) {
+        result[uid][dateStr] = {
+          source: "entry",
+          entryId: entry.id,
+          overrideId: null,
+          user_id: entry.user_id,
+          shift_date: dateStr,
+          project_id: entry.project_id,
+          category: entry.category,
+          note: entry.note,
+          rangeFrom: entry.date_from.toISOString().slice(0, 10),
+          rangeTo: entry.date_to.toISOString().slice(0, 10),
+        };
+      } else {
+        result[uid][dateStr] = null;
+      }
+    }
+  }
+
+  return result;
+}