Use tRPC in other group pages (#249)

* Use tRPC in group edition + group layout

* Use tRPC in group modals

* Use tRPC in group stats

* Use tRPC in group activity

src/trpc/routers/groups/stats/get.procedure.ts

@@ -0,0 +1,35 @@
+import { getGroupExpenses } from '@/lib/api'
+import {
+  getTotalActiveUserPaidFor,
+  getTotalActiveUserShare,
+  getTotalGroupSpending,
+} from '@/lib/totals'
+import { baseProcedure } from '@/trpc/init'
+import { z } from 'zod'
+
+export const getGroupStatsProcedure = baseProcedure
+  .input(
+    z.object({
+      groupId: z.string().min(1),
+      participantId: z.string().optional(),
+    }),
+  )
+  .query(async ({ input: { groupId, participantId } }) => {
+    const expenses = await getGroupExpenses(groupId)
+    const totalGroupSpendings = getTotalGroupSpending(expenses)
+
+    const totalParticipantSpendings =
+      participantId !== undefined
+        ? getTotalActiveUserPaidFor(participantId, expenses)
+        : undefined
+    const totalParticipantShare =
+      participantId !== undefined
+        ? getTotalActiveUserShare(participantId, expenses)
+        : undefined
+
+    return {
+      totalGroupSpendings,
+      totalParticipantSpendings,
+      totalParticipantShare,
+    }
+  })