Add tRPC, use it for group expenses, balances and information page (#246)

* Add tRPC, use it for group expense list

* Use tRPC for balances

* Use tRPC in group information + better loading states

src/trpc/routers/groups/balances/index.ts

@@ -0,0 +1,6 @@
+import { createTRPCRouter } from '@/trpc/init'
+import { listGroupBalancesProcedure } from '@/trpc/routers/groups/balances/list.procedure'
+
+export const groupBalancesRouter = createTRPCRouter({
+  list: listGroupBalancesProcedure,
+})

src/trpc/routers/groups/balances/list.procedure.ts

@@ -0,0 +1,19 @@
+import { getGroupExpenses } from '@/lib/api'
+import {
+  getBalances,
+  getPublicBalances,
+  getSuggestedReimbursements,
+} from '@/lib/balances'
+import { baseProcedure } from '@/trpc/init'
+import { z } from 'zod'
+
+export const listGroupBalancesProcedure = baseProcedure
+  .input(z.object({ groupId: z.string().min(1) }))
+  .query(async ({ input: { groupId } }) => {
+    const expenses = await getGroupExpenses(groupId)
+    const balances = getBalances(expenses)
+    const reimbursements = getSuggestedReimbursements(balances)
+    const publicBalances = getPublicBalances(reimbursements)
+
+    return { balances: publicBalances, reimbursements }
+  })