Add support for group income (= negative expenses) (#158)

* Allow negative amount for expenses to be entered

- an expense becomes an income
- this does not affect calculations, i.e. an income can be split just like an expense

* Incomes should not be reimbursements

when entering a negative number
- deselect 'isReimbursement'
- hide reimbursement checkbox

* Change captions when entering a negative number

- "expense" becomes "income"
- "paid" becomes "received"

* Format incomes on expense list

- replace "paid by" with "received by"

* Format incomes on "Stats" tab

- a group's or participants balance might be negative
- in this case "spendings" will be "earnings" (display accordingly)
- always display positive numbers
- for active user: highlight spendings/earnings in red/green

* Fix typo

---------

Co-authored-by: Sebastien Castiel <sebastien@castiel.me>

.devcontainer/devcontainer.json

@@ -0,0 +1,42 @@
+// For format details, see https://aka.ms/devcontainer.json. For config options, see the
+// README at: https://github.com/devcontainers/templates/tree/main/src/javascript-node-postgres
+{
+    "name": "spliit",
+    "dockerComposeFile": "docker-compose.yml",
+    "service": "app",
+
+    // Features to add to the dev container. More info: https://containers.dev/features.
+    // "features": {
+    // 	   "ghcr.io/frntn/devcontainers-features/prism:1": {}
+    // },
+
+    // Use 'postCreateCommand' to run commands after the container is created.
+    "postCreateCommand": "cp container.env.example .env && npm install",
+    "postAttachCommand": {
+    	"npm": "npm run dev"
+    },
+
+    // Use 'forwardPorts' to make a list of ports inside the container available locally.
+    // This can be used to network with other containers or with the host.
+    "forwardPorts": [3000, 5432],
+    "portsAttributes": {
+            "3000": {
+                "label": "App"
+            },
+            "5432": {
+                "label": "PostgreSQL"
+            }
+    },
+
+    // Configure tool-specific properties.
+    "customizations": {
+        "codespaces": {
+            "openFiles": [
+                "README.md"
+            ]
+        }
+    }
+
+    // Uncomment to connect as root instead. More info: https://aka.ms/dev-containers-non-root.
+    // "remoteUser": "root"
+}

.devcontainer/docker-compose.yml

@@ -0,0 +1,33 @@
+version: '3.8'
+
+services:
+  app:
+    image: mcr.microsoft.com/devcontainers/typescript-node:latest
+
+    volumes:
+      - ../..:/workspaces:cached
+      
+    # Overrides default command so things don't shut down after the process ends.
+    command: sleep infinity
+
+    # Runs app on the same network as the database container, allows "forwardPorts" in devcontainer.json function.
+    network_mode: service:db
+
+    # Use "forwardPorts" in **devcontainer.json** to forward an app port locally. 
+    # (Adding the "ports" property to this file will not forward from a Codespace.)
+
+  db:
+    image: postgres:latest
+    restart: unless-stopped
+    volumes:
+      - postgres-data:/var/lib/postgresql/data
+    environment:
+      POSTGRES_PASSWORD: 1234
+      POSTGRES_USER: postgres
+      POSTGRES_DB: postgres
+
+    # Add "forwardPorts": ["5432"] to **devcontainer.json** to forward PostgreSQL locally.
+    # (Adding the "ports" property to this file will not forward from a Codespace.)
+
+volumes:
+  postgres-data:

.gitignore

@@ -28,6 +28,7 @@ yarn-error.log*
 # local env files
 .env*.local
 *.env
+!scripts/build.env
 
 # vercel
 .vercel

Dockerfile

@@ -1,22 +1,48 @@
-FROM node:21-slim as base
+FROM node:21-alpine as base
+
+WORKDIR /usr/app
+COPY ./package.json \
+     ./package-lock.json \
+     ./next.config.js \
+     ./tsconfig.json \
+     ./reset.d.ts \
+     ./tailwind.config.js \
+     ./postcss.config.js ./
+COPY ./scripts ./scripts
+COPY ./prisma ./prisma
+
+RUN apk add --no-cache openssl && \
+    npm ci --ignore-scripts && \
+    npx prisma generate
+
+COPY ./src ./src
+
+ENV NEXT_TELEMETRY_DISABLED=1
+
+COPY scripts/build.env .env
+RUN npm run build
+
+RUN rm -r .next/cache
+
+FROM node:21-alpine as runtime-deps
+
+WORKDIR /usr/app
+COPY --from=base /usr/app/package.json /usr/app/package-lock.json /usr/app/next.config.js ./
+COPY --from=base /usr/app/prisma ./prisma
+
+RUN npm ci --omit=dev --omit=optional --ignore-scripts && \
+    npx prisma generate
+
+FROM node:21-alpine as runner
 
 EXPOSE 3000/tcp
 WORKDIR /usr/app
-COPY ./ ./
 
-RUN apt update && \
-    apt install openssl -y && \
-    apt clean && \
-    apt autoclean && \
-    apt autoremove && \
-    npm ci --ignore-scripts && \
-    npm install -g prisma && \
-    prisma generate
+COPY --from=base /usr/app/package.json /usr/app/package-lock.json /usr/app/next.config.js ./
+COPY --from=runtime-deps /usr/app/node_modules ./node_modules
+COPY ./public ./public
+COPY ./scripts ./scripts
+COPY --from=base /usr/app/prisma ./prisma
+COPY --from=base /usr/app/.next ./.next
 
-# env vars needed for build not to fail
-ARG POSTGRES_PRISMA_URL
-ARG POSTGRES_URL_NON_POOLING
-
-RUN npm run build
-
-ENTRYPOINT ["/usr/app/scripts/container-entrypoint.sh"]
+ENTRYPOINT ["/bin/sh", "/usr/app/scripts/container-entrypoint.sh"]

next.config.js

@@ -23,6 +23,12 @@ const nextConfig = {
   images: {
     remotePatterns
   },
+  // Required to run in a codespace (see https://github.com/vercel/next.js/issues/58019)
+  experimental: {
+    serverActions: {
+        allowedOrigins: ['localhost:3000'],
+    },
+},
 }
 
 module.exports = nextConfig

package-lock.json

@@ -39,9 +39,11 @@
         "next13-progressbar": "^1.1.1",
         "openai": "^4.25.0",
         "pg": "^8.11.3",
+        "prisma": "^5.7.0",
         "react": "^18.2.0",
         "react-dom": "^18.2.0",
         "react-hook-form": "^7.47.0",
+        "react-intersection-observer": "^9.8.0",
         "sharp": "^0.33.2",
         "tailwind-merge": "^1.14.0",
         "tailwindcss-animate": "^1.0.7",
@@ -65,7 +67,6 @@
         "postcss": "^8",
         "prettier": "^3.0.3",
         "prettier-plugin-organize-imports": "^3.2.3",
-        "prisma": "^5.7.0",
         "tailwindcss": "^3",
         "tsconfig-paths": "^4.2.0",
         "typescript": "^5.3.3"
@@ -1429,13 +1430,10 @@
       }
     },
     "node_modules/@prisma/client": {
-      "version": "5.6.0",
-      "resolved": "https://registry.npmjs.org/@prisma/client/-/client-5.6.0.tgz",
-      "integrity": "sha512-mUDefQFa1wWqk4+JhKPYq8BdVoFk9NFMBXUI8jAkBfQTtgx8WPx02U2HB/XbAz3GSUJpeJOKJQtNvaAIDs6sug==",
+      "version": "5.9.1",
+      "resolved": "https://registry.npmjs.org/@prisma/client/-/client-5.9.1.tgz",
+      "integrity": "sha512-caSOnG4kxcSkhqC/2ShV7rEoWwd3XrftokxJqOCMVvia4NYV/TPtJlS9C2os3Igxw/Qyxumj9GBQzcStzECvtQ==",
       "hasInstallScript": true,
-      "dependencies": {
-        "@prisma/engines-version": "5.6.0-32.e95e739751f42d8ca026f6b910f5a2dc5adeaeee"
-      },
       "engines": {
         "node": ">=16.13"
       },
@@ -1449,59 +1447,48 @@
       }
     },
     "node_modules/@prisma/debug": {
-      "version": "5.7.0",
-      "resolved": "https://registry.npmjs.org/@prisma/debug/-/debug-5.7.0.tgz",
-      "integrity": "sha512-tZ+MOjWlVvz1kOEhNYMa4QUGURY+kgOUBqLHYIV8jmCsMuvA1tWcn7qtIMLzYWCbDcQT4ZS8xDgK0R2gl6/0wA==",
-      "devOptional": true
+      "version": "5.9.1",
+      "resolved": "https://registry.npmjs.org/@prisma/debug/-/debug-5.9.1.tgz",
+      "integrity": "sha512-yAHFSFCg8KVoL0oRUno3m60GAjsUKYUDkQ+9BA2X2JfVR3kRVSJFc/GpQ2fSORi4pSHZR9orfM4UC9OVXIFFTA=="
     },
     "node_modules/@prisma/engines": {
-      "version": "5.7.0",
-      "resolved": "https://registry.npmjs.org/@prisma/engines/-/engines-5.7.0.tgz",
-      "integrity": "sha512-TkOMgMm60n5YgEKPn9erIvFX2/QuWnl3GBo6yTRyZKk5O5KQertXiNnrYgSLy0SpsKmhovEPQb+D4l0SzyE7XA==",
-      "devOptional": true,
+      "version": "5.9.1",
+      "resolved": "https://registry.npmjs.org/@prisma/engines/-/engines-5.9.1.tgz",
+      "integrity": "sha512-gkdXmjxQ5jktxWNdDA5aZZ6R8rH74JkoKq6LD5mACSvxd2vbqWeWIOV0Py5wFC8vofOYShbt6XUeCIUmrOzOnQ==",
       "hasInstallScript": true,
       "dependencies": {
-        "@prisma/debug": "5.7.0",
-        "@prisma/engines-version": "5.7.0-41.79fb5193cf0a8fdbef536e4b4a159cad677ab1b9",
-        "@prisma/fetch-engine": "5.7.0",
-        "@prisma/get-platform": "5.7.0"
+        "@prisma/debug": "5.9.1",
+        "@prisma/engines-version": "5.9.0-32.23fdc5965b1e05fc54e5f26ed3de66776b93de64",
+        "@prisma/fetch-engine": "5.9.1",
+        "@prisma/get-platform": "5.9.1"
       }
     },
-    "node_modules/@prisma/engines-version": {
-      "version": "5.6.0-32.e95e739751f42d8ca026f6b910f5a2dc5adeaeee",
-      "resolved": "https://registry.npmjs.org/@prisma/engines-version/-/engines-version-5.6.0-32.e95e739751f42d8ca026f6b910f5a2dc5adeaeee.tgz",
-      "integrity": "sha512-UoFgbV1awGL/3wXuUK3GDaX2SolqczeeJ5b4FVec9tzeGbSWJboPSbT0psSrmgYAKiKnkOPFSLlH6+b+IyOwAw=="
-    },
     "node_modules/@prisma/engines/node_modules/@prisma/engines-version": {
-      "version": "5.7.0-41.79fb5193cf0a8fdbef536e4b4a159cad677ab1b9",
-      "resolved": "https://registry.npmjs.org/@prisma/engines-version/-/engines-version-5.7.0-41.79fb5193cf0a8fdbef536e4b4a159cad677ab1b9.tgz",
-      "integrity": "sha512-V6tgRVi62jRwTm0Hglky3Scwjr/AKFBFtS+MdbsBr7UOuiu1TKLPc6xfPiyEN1+bYqjEtjxwGsHgahcJsd1rNg==",
-      "devOptional": true
+      "version": "5.9.0-32.23fdc5965b1e05fc54e5f26ed3de66776b93de64",
+      "resolved": "https://registry.npmjs.org/@prisma/engines-version/-/engines-version-5.9.0-32.23fdc5965b1e05fc54e5f26ed3de66776b93de64.tgz",
+      "integrity": "sha512-HFl7275yF0FWbdcNvcSRbbu9JCBSLMcurYwvWc8WGDnpu7APxQo2ONtZrUggU3WxLxUJ2uBX+0GOFIcJeVeOOQ=="
     },
     "node_modules/@prisma/fetch-engine": {
-      "version": "5.7.0",
-      "resolved": "https://registry.npmjs.org/@prisma/fetch-engine/-/fetch-engine-5.7.0.tgz",
-      "integrity": "sha512-zIn/qmO+N/3FYe7/L9o+yZseIU8ivh4NdPKSkQRIHfg2QVTVMnbhGoTcecbxfVubeTp+DjcbjS0H9fCuM4W04w==",
-      "devOptional": true,
+      "version": "5.9.1",
+      "resolved": "https://registry.npmjs.org/@prisma/fetch-engine/-/fetch-engine-5.9.1.tgz",
+      "integrity": "sha512-l0goQOMcNVOJs1kAcwqpKq3ylvkD9F04Ioe1oJoCqmz05mw22bNAKKGWuDd3zTUoUZr97va0c/UfLNru+PDmNA==",
       "dependencies": {
-        "@prisma/debug": "5.7.0",
-        "@prisma/engines-version": "5.7.0-41.79fb5193cf0a8fdbef536e4b4a159cad677ab1b9",
-        "@prisma/get-platform": "5.7.0"
+        "@prisma/debug": "5.9.1",
+        "@prisma/engines-version": "5.9.0-32.23fdc5965b1e05fc54e5f26ed3de66776b93de64",
+        "@prisma/get-platform": "5.9.1"
       }
     },
     "node_modules/@prisma/fetch-engine/node_modules/@prisma/engines-version": {
-      "version": "5.7.0-41.79fb5193cf0a8fdbef536e4b4a159cad677ab1b9",
-      "resolved": "https://registry.npmjs.org/@prisma/engines-version/-/engines-version-5.7.0-41.79fb5193cf0a8fdbef536e4b4a159cad677ab1b9.tgz",
-      "integrity": "sha512-V6tgRVi62jRwTm0Hglky3Scwjr/AKFBFtS+MdbsBr7UOuiu1TKLPc6xfPiyEN1+bYqjEtjxwGsHgahcJsd1rNg==",
-      "devOptional": true
+      "version": "5.9.0-32.23fdc5965b1e05fc54e5f26ed3de66776b93de64",
+      "resolved": "https://registry.npmjs.org/@prisma/engines-version/-/engines-version-5.9.0-32.23fdc5965b1e05fc54e5f26ed3de66776b93de64.tgz",
+      "integrity": "sha512-HFl7275yF0FWbdcNvcSRbbu9JCBSLMcurYwvWc8WGDnpu7APxQo2ONtZrUggU3WxLxUJ2uBX+0GOFIcJeVeOOQ=="
     },
     "node_modules/@prisma/get-platform": {
-      "version": "5.7.0",
-      "resolved": "https://registry.npmjs.org/@prisma/get-platform/-/get-platform-5.7.0.tgz",
-      "integrity": "sha512-ZeV/Op4bZsWXuw5Tg05WwRI8BlKiRFhsixPcAM+5BKYSiUZiMKIi713tfT3drBq8+T0E1arNZgYSA9QYcglWNA==",
-      "devOptional": true,
+      "version": "5.9.1",
+      "resolved": "https://registry.npmjs.org/@prisma/get-platform/-/get-platform-5.9.1.tgz",
+      "integrity": "sha512-6OQsNxTyhvG+T2Ksr8FPFpuPeL4r9u0JF0OZHUBI/Uy9SS43sPyAIutt4ZEAyqWQt104ERh70EZedkHZKsnNbg==",
       "dependencies": {
-        "@prisma/debug": "5.7.0"
+        "@prisma/debug": "5.9.1"
       }
     },
     "node_modules/@radix-ui/number": {
@@ -7430,13 +7417,12 @@
       }
     },
     "node_modules/prisma": {
-      "version": "5.7.0",
-      "resolved": "https://registry.npmjs.org/prisma/-/prisma-5.7.0.tgz",
-      "integrity": "sha512-0rcfXO2ErmGAtxnuTNHQT9ztL0zZheQjOI/VNJzdq87C3TlGPQtMqtM+KCwU6XtmkoEr7vbCQqA7HF9IY0ST+Q==",
-      "devOptional": true,
+      "version": "5.9.1",
+      "resolved": "https://registry.npmjs.org/prisma/-/prisma-5.9.1.tgz",
+      "integrity": "sha512-Hy/8KJZz0ELtkw4FnG9MS9rNWlXcJhf98Z2QMqi0QiVMoS8PzsBkpla0/Y5hTlob8F3HeECYphBjqmBxrluUrQ==",
       "hasInstallScript": true,
       "dependencies": {
-        "@prisma/engines": "5.7.0"
+        "@prisma/engines": "5.9.1"
       },
       "bin": {
         "prisma": "build/index.js"
@@ -7525,6 +7511,20 @@
         "react": "^16.8.0 || ^17 || ^18"
       }
     },
+    "node_modules/react-intersection-observer": {
+      "version": "9.8.0",
+      "resolved": "https://registry.npmjs.org/react-intersection-observer/-/react-intersection-observer-9.8.0.tgz",
+      "integrity": "sha512-wXHvMQUsTagh3X0Z6jDtGkIXc3VVCd2tjDRYR9kII3GKrZr0XF0xtpfdamo2n8BSF+zzfeeBVOTjxZWpBp9X0g==",
+      "peerDependencies": {
+        "react": "^15.0.0 || ^16.0.0 || ^17.0.0 || ^18.0.0",
+        "react-dom": "^15.0.0 || ^16.0.0 || ^17.0.0 || ^18.0.0"
+      },
+      "peerDependenciesMeta": {
+        "react-dom": {
+          "optional": true
+        }
+      }
+    },
     "node_modules/react-is": {
       "version": "16.13.1",
       "resolved": "https://registry.npmjs.org/react-is/-/react-is-16.13.1.tgz",

package.json

@@ -9,6 +9,7 @@
     "lint": "next lint",
     "check-types": "tsc --noEmit",
     "check-formatting": "prettier -c src",
+    "prettier": "prettier -w src",
     "postinstall": "prisma migrate deploy && prisma generate",
     "build-image": "./scripts/build-image.sh",
     "start-container": "docker compose --env-file container.env up"
@@ -47,13 +48,15 @@
     "react": "^18.2.0",
     "react-dom": "^18.2.0",
     "react-hook-form": "^7.47.0",
+    "react-intersection-observer": "^9.8.0",
     "sharp": "^0.33.2",
     "tailwind-merge": "^1.14.0",
     "tailwindcss-animate": "^1.0.7",
     "ts-pattern": "^5.0.6",
     "uuid": "^9.0.1",
     "vaul": "^0.8.0",
-    "zod": "^3.22.4"
+    "zod": "^3.22.4",
+    "prisma": "^5.7.0"
   },
   "devDependencies": {
     "@total-typescript/ts-reset": "^0.5.1",
@@ -70,7 +73,6 @@
     "postcss": "^8",
     "prettier": "^3.0.3",
     "prettier-plugin-organize-imports": "^3.2.3",
-    "prisma": "^5.7.0",
     "tailwindcss": "^3",
     "tsconfig-paths": "^4.2.0",
     "typescript": "^5.3.3"

prisma/migrations/20240310194006_add_notes_in_expense/migration.sql

@@ -0,0 +1,2 @@
+-- AlterTable
+ALTER TABLE "Expense" ADD COLUMN     "notes" TEXT;

prisma/migrations/20240414135355_add_activity_log/migration.sql

@@ -0,0 +1,18 @@
+-- CreateEnum
+CREATE TYPE "ActivityType" AS ENUM ('UPDATE_GROUP', 'CREATE_EXPENSE', 'UPDATE_EXPENSE', 'DELETE_EXPENSE');
+
+-- CreateTable
+CREATE TABLE "Activity" (
+    "id" TEXT NOT NULL,
+    "groupId" TEXT NOT NULL,
+    "time" TIMESTAMP(3) NOT NULL DEFAULT CURRENT_TIMESTAMP,
+    "activityType" "ActivityType" NOT NULL,
+    "participantId" TEXT,
+    "expenseId" TEXT,
+    "data" TEXT,
+
+    CONSTRAINT "Activity_pkey" PRIMARY KEY ("id")
+);
+
+-- AddForeignKey
+ALTER TABLE "Activity" ADD CONSTRAINT "Activity_groupId_fkey" FOREIGN KEY ("groupId") REFERENCES "Group"("id") ON DELETE RESTRICT ON UPDATE CASCADE;

prisma/schema.prisma

@@ -17,6 +17,7 @@ model Group {
   currency     String        @default("$")
   participants Participant[]
   expenses     Expense[]
+  activities   Activity[]
   createdAt    DateTime      @default(now())
 }
 
@@ -52,6 +53,7 @@ model Expense {
   splitMode       SplitMode         @default(EVENLY)
   createdAt       DateTime          @default(now())
   documents       ExpenseDocument[]
+  notes           String?
 }
 
 model ExpenseDocument {
@@ -79,3 +81,21 @@ model ExpensePaidFor {
 
   @@id([expenseId, participantId])
 }
+
+model Activity {
+  id            String       @id
+  group         Group        @relation(fields: [groupId], references: [id])
+  groupId       String
+  time          DateTime     @default(now())
+  activityType  ActivityType
+  participantId String?
+  expenseId     String?
+  data          String?
+}
+
+enum ActivityType {
+  UPDATE_GROUP
+  CREATE_EXPENSE
+  UPDATE_EXPENSE
+  DELETE_EXPENSE
+}

scripts/build-image.sh

@@ -5,9 +5,6 @@ SPLIIT_VERSION=$(node -p -e "require('./package.json').version")
 
 # we need to set dummy data for POSTGRES env vars in order for build not to fail
 docker buildx build \
-    --no-cache \
-    --build-arg POSTGRES_PRISMA_URL=postgresql://build:@db \
-    --build-arg POSTGRES_URL_NON_POOLING=postgresql://build:@db \
     -t ${SPLIIT_APP_NAME}:${SPLIIT_VERSION} \
     -t ${SPLIIT_APP_NAME}:latest \
     .

scripts/build.env

@@ -0,0 +1,22 @@
+# build file that contains all possible env vars with mocked values
+# as most of them are used at build time in order to have the production build to work properly
+
+# db
+POSTGRES_PASSWORD=1234
+
+# app
+POSTGRES_PRISMA_URL=postgresql://postgres:${POSTGRES_PASSWORD}@db
+POSTGRES_URL_NON_POOLING=postgresql://postgres:${POSTGRES_PASSWORD}@db
+
+# app-minio
+NEXT_PUBLIC_ENABLE_EXPENSE_DOCUMENTS=false
+S3_UPLOAD_KEY=AAAAAAAAAAAAAAAAAAAA
+S3_UPLOAD_SECRET=AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
+S3_UPLOAD_BUCKET=spliit
+S3_UPLOAD_REGION=eu-north-1
+S3_UPLOAD_ENDPOINT=s3://minio.example.com
+
+# app-openai
+NEXT_PUBLIC_ENABLE_RECEIPT_EXTRACT=false
+OPENAI_API_KEY=XXXXXXXXXXXXXXXXXXXXXXXXXXXX
+NEXT_PUBLIC_ENABLE_CATEGORY_EXTRACT=false

scripts/container-entrypoint.sh

@@ -1,3 +1,6 @@
 #!/bin/bash
-prisma migrate deploy
+
+set -euxo pipefail
+
+npx prisma migrate deploy
 npm run start

scripts/start-local-db.sh

@@ -6,6 +6,6 @@ else
     echo "postgres is not running, starting it"
     docker rm postgres --force
     mkdir -p postgres-data
-    docker run --name postgres -d -p 5432:5432 -e POSTGRES_PASSWORD=1234 -v ./postgres-data:/var/lib/postgresql/data postgres
+    docker run --name postgres -d -p 5432:5432 -e POSTGRES_PASSWORD=1234 -v "/$(pwd)/postgres-data:/var/lib/postgresql/data" postgres
     sleep 5 # Wait for postgres to start
 fi

src/app/groups/[groupId]/activity/activity-item.tsx

@@ -0,0 +1,102 @@
+'use client'
+import { Button } from '@/components/ui/button'
+import { getGroupExpenses } from '@/lib/api'
+import { DateTimeStyle, cn, formatDate } from '@/lib/utils'
+import { Activity, ActivityType, Participant } from '@prisma/client'
+import { ChevronRight } from 'lucide-react'
+import Link from 'next/link'
+import { useRouter } from 'next/navigation'
+
+type Props = {
+  groupId: string
+  activity: Activity
+  participant?: Participant
+  expense?: Awaited<ReturnType<typeof getGroupExpenses>>[number]
+  dateStyle: DateTimeStyle
+}
+
+function getSummary(activity: Activity, participantName?: string) {
+  const participant = participantName ?? 'Someone'
+  const expense = activity.data ?? ''
+  if (activity.activityType == ActivityType.UPDATE_GROUP) {
+    return (
+      <>
+        Group settings were modified by <strong>{participant}</strong>
+      </>
+    )
+  } else if (activity.activityType == ActivityType.CREATE_EXPENSE) {
+    return (
+      <>
+        Expense <em>&ldquo;{expense}&rdquo;</em> created by{' '}
+        <strong>{participant}</strong>.
+      </>
+    )
+  } else if (activity.activityType == ActivityType.UPDATE_EXPENSE) {
+    return (
+      <>
+        Expense <em>&ldquo;{expense}&rdquo;</em> updated by{' '}
+        <strong>{participant}</strong>.
+      </>
+    )
+  } else if (activity.activityType == ActivityType.DELETE_EXPENSE) {
+    return (
+      <>
+        Expense <em>&ldquo;{expense}&rdquo;</em> deleted by{' '}
+        <strong>{participant}</strong>.
+      </>
+    )
+  }
+}
+
+export function ActivityItem({
+  groupId,
+  activity,
+  participant,
+  expense,
+  dateStyle,
+}: Props) {
+  const router = useRouter()
+
+  const expenseExists = expense !== undefined
+  const summary = getSummary(activity, participant?.name)
+
+  return (
+    <div
+      className={cn(
+        'flex justify-between sm:rounded-lg px-2 sm:pr-1 sm:pl-2 py-2 text-sm hover:bg-accent gap-1 items-stretch',
+        expenseExists && 'cursor-pointer',
+      )}
+      onClick={() => {
+        if (expenseExists) {
+          router.push(`/groups/${groupId}/expenses/${activity.expenseId}/edit`)
+        }
+      }}
+    >
+      <div className="flex flex-col justify-between items-start">
+        {dateStyle !== undefined && (
+          <div className="mt-1 text-xs/5 text-muted-foreground">
+            {formatDate(activity.time, { dateStyle })}
+          </div>
+        )}
+        <div className="my-1 text-xs/5 text-muted-foreground">
+          {formatDate(activity.time, { timeStyle: 'short' })}
+        </div>
+      </div>
+      <div className="flex-1">
+        <div className="m-1">{summary}</div>
+      </div>
+      {expenseExists && (
+        <Button
+          size="icon"
+          variant="link"
+          className="self-center hidden sm:flex w-5 h-5"
+          asChild
+        >
+          <Link href={`/groups/${groupId}/expenses/${activity.expenseId}/edit`}>
+            <ChevronRight className="w-4 h-4" />
+          </Link>
+        </Button>
+      )}
+    </div>
+  )
+}

src/app/groups/[groupId]/activity/activity-list.tsx

@@ -0,0 +1,112 @@
+import { ActivityItem } from '@/app/groups/[groupId]/activity/activity-item'
+import { getGroupExpenses } from '@/lib/api'
+import { Activity, Participant } from '@prisma/client'
+import dayjs, { type Dayjs } from 'dayjs'
+
+type Props = {
+  groupId: string
+  participants: Participant[]
+  expenses: Awaited<ReturnType<typeof getGroupExpenses>>
+  activities: Activity[]
+}
+
+const DATE_GROUPS = {
+  TODAY: 'Today',
+  YESTERDAY: 'Yesterday',
+  EARLIER_THIS_WEEK: 'Earlier this week',
+  LAST_WEEK: 'Last week',
+  EARLIER_THIS_MONTH: 'Earlier this month',
+  LAST_MONTH: 'Last month',
+  EARLIER_THIS_YEAR: 'Earlier this year',
+  LAST_YEAR: 'Last year',
+  OLDER: 'Older',
+}
+
+function getDateGroup(date: Dayjs, today: Dayjs) {
+  if (today.isSame(date, 'day')) {
+    return DATE_GROUPS.TODAY
+  } else if (today.subtract(1, 'day').isSame(date, 'day')) {
+    return DATE_GROUPS.YESTERDAY
+  } else if (today.isSame(date, 'week')) {
+    return DATE_GROUPS.EARLIER_THIS_WEEK
+  } else if (today.subtract(1, 'week').isSame(date, 'week')) {
+    return DATE_GROUPS.LAST_WEEK
+  } else if (today.isSame(date, 'month')) {
+    return DATE_GROUPS.EARLIER_THIS_MONTH
+  } else if (today.subtract(1, 'month').isSame(date, 'month')) {
+    return DATE_GROUPS.LAST_MONTH
+  } else if (today.isSame(date, 'year')) {
+    return DATE_GROUPS.EARLIER_THIS_YEAR
+  } else if (today.subtract(1, 'year').isSame(date, 'year')) {
+    return DATE_GROUPS.LAST_YEAR
+  } else {
+    return DATE_GROUPS.OLDER
+  }
+}
+
+function getGroupedActivitiesByDate(activities: Activity[]) {
+  const today = dayjs()
+  return activities.reduce(
+    (result: { [key: string]: Activity[] }, activity: Activity) => {
+      const activityGroup = getDateGroup(dayjs(activity.time), today)
+      result[activityGroup] = result[activityGroup] ?? []
+      result[activityGroup].push(activity)
+      return result
+    },
+    {},
+  )
+}
+
+export function ActivityList({
+  groupId,
+  participants,
+  expenses,
+  activities,
+}: Props) {
+  const groupedActivitiesByDate = getGroupedActivitiesByDate(activities)
+
+  return activities.length > 0 ? (
+    <>
+      {Object.values(DATE_GROUPS).map((dateGroup: string) => {
+        let groupActivities = groupedActivitiesByDate[dateGroup]
+        if (!groupActivities || groupActivities.length === 0) return null
+        const dateStyle =
+          dateGroup == DATE_GROUPS.TODAY || dateGroup == DATE_GROUPS.YESTERDAY
+            ? undefined
+            : 'medium'
+
+        return (
+          <div key={dateGroup}>
+            <div
+              className={
+                'text-muted-foreground text-xs py-1 font-semibold sticky top-16 bg-white dark:bg-[#1b1917]'
+              }
+            >
+              {dateGroup}
+            </div>
+            {groupActivities.map((activity: Activity) => {
+              const participant =
+                activity.participantId !== null
+                  ? participants.find((p) => p.id === activity.participantId)
+                  : undefined
+              const expense =
+                activity.expenseId !== null
+                  ? expenses.find((e) => e.id === activity.expenseId)
+                  : undefined
+              return (
+                <ActivityItem
+                  key={activity.id}
+                  {...{ groupId, activity, participant, expense, dateStyle }}
+                />
+              )
+            })}
+          </div>
+        )
+      })}
+    </>
+  ) : (
+    <p className="px-6 text-sm py-6">
+      There is not yet any activity in your group.
+    </p>
+  )
+}

src/app/groups/[groupId]/activity/page.tsx

@@ -0,0 +1,51 @@
+import { cached } from '@/app/cached-functions'
+import { ActivityList } from '@/app/groups/[groupId]/activity/activity-list'
+import {
+  Card,
+  CardContent,
+  CardDescription,
+  CardHeader,
+  CardTitle,
+} from '@/components/ui/card'
+import { getActivities, getGroupExpenses } from '@/lib/api'
+import { Metadata } from 'next'
+import { notFound } from 'next/navigation'
+
+export const metadata: Metadata = {
+  title: 'Activity',
+}
+
+export default async function ActivityPage({
+  params: { groupId },
+}: {
+  params: { groupId: string }
+}) {
+  const group = await cached.getGroup(groupId)
+  if (!group) notFound()
+
+  const expenses = await getGroupExpenses(groupId)
+  const activities = await getActivities(groupId)
+
+  return (
+    <>
+      <Card className="mb-4">
+        <CardHeader>
+          <CardTitle>Activity</CardTitle>
+          <CardDescription>
+            Overview of all activity in this group.
+          </CardDescription>
+        </CardHeader>
+        <CardContent className="flex flex-col space-y-4">
+          <ActivityList
+            {...{
+              groupId,
+              participants: group.participants,
+              expenses,
+              activities,
+            }}
+          />
+        </CardContent>
+      </Card>
+    </>
+  )
+}

src/app/groups/[groupId]/edit/page.tsx

@@ -17,10 +17,10 @@ export default async function EditGroupPage({
   const group = await cached.getGroup(groupId)
   if (!group) notFound()
 
-  async function updateGroupAction(values: unknown) {
+  async function updateGroupAction(values: unknown, participantId?: string) {
     'use server'
     const groupFormValues = groupFormSchema.parse(values)
-    const group = await updateGroup(groupId, groupFormValues)
+    const group = await updateGroup(groupId, groupFormValues, participantId)
     redirect(`/groups/${group.id}`)
   }
 

src/app/groups/[groupId]/expenses/[expenseId]/edit/page.tsx

@@ -6,6 +6,7 @@ import {
   getExpense,
   updateExpense,
 } from '@/lib/api'
+import { getRuntimeFeatureFlags } from '@/lib/featureFlags'
 import { expenseFormSchema } from '@/lib/schemas'
 import { Metadata } from 'next'
 import { notFound, redirect } from 'next/navigation'
@@ -26,16 +27,16 @@ export default async function EditExpensePage({
   const expense = await getExpense(groupId, expenseId)
   if (!expense) notFound()
 
-  async function updateExpenseAction(values: unknown) {
+  async function updateExpenseAction(values: unknown, participantId?: string) {
     'use server'
     const expenseFormValues = expenseFormSchema.parse(values)
-    await updateExpense(groupId, expenseId, expenseFormValues)
+    await updateExpense(groupId, expenseId, expenseFormValues, participantId)
     redirect(`/groups/${groupId}`)
   }
 
-  async function deleteExpenseAction() {
+  async function deleteExpenseAction(participantId?: string) {
     'use server'
-    await deleteExpense(expenseId)
+    await deleteExpense(groupId, expenseId, participantId)
     redirect(`/groups/${groupId}`)
   }
 
@@ -47,6 +48,7 @@ export default async function EditExpensePage({
         categories={categories}
         onSubmit={updateExpenseAction}
         onDelete={deleteExpenseAction}
+        runtimeFeatureFlags={await getRuntimeFeatureFlags()}
       />
     </Suspense>
   )

src/app/groups/[groupId]/expenses/active-user-balance.tsx

@@ -0,0 +1,43 @@
+'use client'
+import { Money } from '@/components/money'
+import { getBalances } from '@/lib/balances'
+import { useActiveUser } from '@/lib/hooks'
+
+type Props = {
+  groupId: string
+  currency: string
+  expense: Parameters<typeof getBalances>[0][number]
+}
+
+export function ActiveUserBalance({ groupId, currency, expense }: Props) {
+  const activeUserId = useActiveUser(groupId)
+  if (activeUserId === null || activeUserId === '' || activeUserId === 'None') {
+    return null
+  }
+
+  const balances = getBalances([expense])
+  let fmtBalance = <>You are not involved</>
+  if (Object.hasOwn(balances, activeUserId)) {
+    const balance = balances[activeUserId]
+    let balanceDetail = <></>
+    if (balance.paid > 0 && balance.paidFor > 0) {
+      balanceDetail = (
+        <>
+          {' ('}
+          <Money {...{ currency, amount: balance.paid }} />
+          {' - '}
+          <Money {...{ currency, amount: balance.paidFor }} />
+          {')'}
+        </>
+      )
+    }
+    fmtBalance = (
+      <>
+        Your balance:{' '}
+        <Money {...{ currency, amount: balance.total }} bold colored />
+        {balanceDetail}
+      </>
+    )
+  }
+  return <div className="text-xs text-muted-foreground">{fmtBalance}</div>
+}

src/app/groups/[groupId]/expenses/create-from-receipt-button.tsx

@@ -26,7 +26,7 @@ import {
 import { ToastAction } from '@/components/ui/toast'
 import { useToast } from '@/components/ui/use-toast'
 import { useMediaQuery } from '@/lib/hooks'
-import { formatCurrency, formatExpenseDate, formatFileSize } from '@/lib/utils'
+import { formatCurrency, formatDate, formatFileSize } from '@/lib/utils'
 import { Category } from '@prisma/client'
 import { ChevronRight, FileQuestion, Loader2, Receipt } from 'lucide-react'
 import { getImageData, usePresignedUpload } from 'next-s3-upload'
@@ -212,9 +212,9 @@ export function CreateFromReceiptButton({
               <div>
                 {receiptInfo ? (
                   receiptInfo.date ? (
-                    formatExpenseDate(
-                      new Date(`${receiptInfo?.date}T12:00:00.000Z`),
-                    )
+                    formatDate(new Date(`${receiptInfo?.date}T12:00:00.000Z`), {
+                      dateStyle: 'medium',
+                    })
                   ) : (
                     <Unknown />
                   )

src/app/groups/[groupId]/expenses/create/page.tsx

@@ -1,6 +1,7 @@
 import { cached } from '@/app/cached-functions'
 import { ExpenseForm } from '@/components/expense-form'
 import { createExpense, getCategories } from '@/lib/api'
+import { getRuntimeFeatureFlags } from '@/lib/featureFlags'
 import { expenseFormSchema } from '@/lib/schemas'
 import { Metadata } from 'next'
 import { notFound, redirect } from 'next/navigation'
@@ -19,10 +20,10 @@ export default async function ExpensePage({
   const group = await cached.getGroup(groupId)
   if (!group) notFound()
 
-  async function createExpenseAction(values: unknown) {
+  async function createExpenseAction(values: unknown, participantId?: string) {
     'use server'
     const expenseFormValues = expenseFormSchema.parse(values)
-    await createExpense(expenseFormValues, groupId)
+    await createExpense(expenseFormValues, groupId, participantId)
     redirect(`/groups/${groupId}`)
   }
 
@@ -32,6 +33,7 @@ export default async function ExpensePage({
         group={group}
         categories={categories}
         onSubmit={createExpenseAction}
+        runtimeFeatureFlags={await getRuntimeFeatureFlags()}
       />
     </Suspense>
   )

src/app/groups/[groupId]/expenses/expense-card.tsx

@@ -0,0 +1,79 @@
+'use client'
+import { ActiveUserBalance } from '@/app/groups/[groupId]/expenses/active-user-balance'
+import { CategoryIcon } from '@/app/groups/[groupId]/expenses/category-icon'
+import { Button } from '@/components/ui/button'
+import { getGroupExpenses } from '@/lib/api'
+import { cn, formatCurrency, formatDate } from '@/lib/utils'
+import { ChevronRight } from 'lucide-react'
+import Link from 'next/link'
+import { useRouter } from 'next/navigation'
+import { Fragment } from 'react'
+
+type Props = {
+  expense: Awaited<ReturnType<typeof getGroupExpenses>>[number]
+  currency: string
+  groupId: string
+}
+
+export function ExpenseCard({ expense, currency, groupId }: Props) {
+  const router = useRouter()
+
+  return (
+    <div
+      key={expense.id}
+      className={cn(
+        'flex justify-between sm:mx-6 px-4 sm:rounded-lg sm:pr-2 sm:pl-4 py-4 text-sm cursor-pointer hover:bg-accent gap-1 items-stretch',
+        expense.isReimbursement && 'italic',
+      )}
+      onClick={() => {
+        router.push(`/groups/${groupId}/expenses/${expense.id}/edit`)
+      }}
+    >
+      <CategoryIcon
+        category={expense.category}
+        className="w-4 h-4 mr-2 mt-0.5 text-muted-foreground"
+      />
+      <div className="flex-1">
+        <div className={cn('mb-1', expense.isReimbursement && 'italic')}>
+          {expense.title}
+        </div>
+        <div className="text-xs text-muted-foreground">
+          {expense.amount > 0 ? 'Paid by ' : 'Received by '}
+          <strong>{expense.paidBy.name}</strong> for{' '}
+          {expense.paidFor.map((paidFor, index) => (
+            <Fragment key={index}>
+              {index !== 0 && <>, </>}
+              <strong>{paidFor.participant.name}</strong>
+            </Fragment>
+          ))}
+        </div>
+        <div className="text-xs text-muted-foreground">
+          <ActiveUserBalance {...{ groupId, currency, expense }} />
+        </div>
+      </div>
+      <div className="flex flex-col justify-between items-end">
+        <div
+          className={cn(
+            'tabular-nums whitespace-nowrap',
+            expense.isReimbursement ? 'italic' : 'font-bold',
+          )}
+        >
+          {formatCurrency(currency, expense.amount)}
+        </div>
+        <div className="text-xs text-muted-foreground">
+          {formatDate(expense.expenseDate, { dateStyle: 'medium' })}
+        </div>
+      </div>
+      <Button
+        size="icon"
+        variant="link"
+        className="self-center hidden sm:flex"
+        asChild
+      >
+        <Link href={`/groups/${groupId}/expenses/${expense.id}/edit`}>
+          <ChevronRight className="w-4 h-4" />
+        </Link>
+      </Button>
+    </div>
+  )
+}

src/app/groups/[groupId]/expenses/expense-list-fetch-action.ts

@@ -0,0 +1,16 @@
+'use server'
+
+import { getGroupExpenses } from '@/lib/api'
+
+export async function getGroupExpensesAction(
+  groupId: string,
+  options?: { offset: number; length: number },
+) {
+  'use server'
+
+  try {
+    return getGroupExpenses(groupId, options)
+  } catch {
+    return null
+  }
+}

src/app/groups/[groupId]/expenses/expense-list.tsx

@@ -1,24 +1,29 @@
 'use client'
-import { CategoryIcon } from '@/app/groups/[groupId]/expenses/category-icon'
+import { ExpenseCard } from '@/app/groups/[groupId]/expenses/expense-card'
+import { getGroupExpensesAction } from '@/app/groups/[groupId]/expenses/expense-list-fetch-action'
 import { Button } from '@/components/ui/button'
 import { SearchBar } from '@/components/ui/search-bar'
-import { getGroupExpenses } from '@/lib/api'
-import { cn, formatCurrency, formatExpenseDate } from '@/lib/utils'
-import { Expense, Participant } from '@prisma/client'
+import { Skeleton } from '@/components/ui/skeleton'
+import { Participant } from '@prisma/client'
 import dayjs, { type Dayjs } from 'dayjs'
-import { ChevronRight } from 'lucide-react'
 import Link from 'next/link'
-import { useRouter } from 'next/navigation'
-import { Fragment, useEffect, useState } from 'react'
+import { useEffect, useMemo, useState } from 'react'
+import { useInView } from 'react-intersection-observer'
+
+type ExpensesType = NonNullable<
+  Awaited<ReturnType<typeof getGroupExpensesAction>>
+>
 
 type Props = {
-  expenses: Awaited<ReturnType<typeof getGroupExpenses>>
+  expensesFirstPage: ExpensesType
+  expenseCount: number
   participants: Participant[]
   currency: string
   groupId: string
 }
 
 const EXPENSE_GROUPS = {
+  UPCOMING: 'Upcoming',
   THIS_WEEK: 'This week',
   EARLIER_THIS_MONTH: 'Earlier this month',
   LAST_MONTH: 'Last month',
@@ -28,7 +33,9 @@ const EXPENSE_GROUPS = {
 }
 
 function getExpenseGroup(date: Dayjs, today: Dayjs) {
-  if (today.isSame(date, 'week')) {
+  if (today.isBefore(date)) {
+    return EXPENSE_GROUPS.UPCOMING
+  } else if (today.isSame(date, 'week')) {
     return EXPENSE_GROUPS.THIS_WEEK
   } else if (today.isSame(date, 'month')) {
     return EXPENSE_GROUPS.EARLIER_THIS_MONTH
@@ -43,28 +50,32 @@ function getExpenseGroup(date: Dayjs, today: Dayjs) {
   }
 }
 
-function getGroupedExpensesByDate(
-  expenses: Awaited<ReturnType<typeof getGroupExpenses>>,
-) {
+function getGroupedExpensesByDate(expenses: ExpensesType) {
   const today = dayjs()
-  return expenses.reduce(
-    (result: { [key: string]: Expense[] }, expense: Expense) => {
-      const expenseGroup = getExpenseGroup(dayjs(expense.expenseDate), today)
-      result[expenseGroup] = result[expenseGroup] ?? []
-      result[expenseGroup].push(expense)
-      return result
-    },
-    {},
-  )
+  return expenses.reduce((result: { [key: string]: ExpensesType }, expense) => {
+    const expenseGroup = getExpenseGroup(dayjs(expense.expenseDate), today)
+    result[expenseGroup] = result[expenseGroup] ?? []
+    result[expenseGroup].push(expense)
+    return result
+  }, {})
 }
 
 export function ExpenseList({
-  expenses,
+  expensesFirstPage,
+  expenseCount,
   currency,
   participants,
   groupId,
 }: Props) {
+  const firstLen = expensesFirstPage.length
   const [searchText, setSearchText] = useState('')
+  const [dataIndex, setDataIndex] = useState(firstLen)
+  const [dataLen, setDataLen] = useState(firstLen)
+  const [hasMoreData, setHasMoreData] = useState(expenseCount > firstLen)
+  const [isFetching, setIsFetching] = useState(false)
+  const [expenses, setExpenses] = useState(expensesFirstPage)
+  const { ref, inView } = useInView()
+
   useEffect(() => {
     const activeUser = localStorage.getItem('newGroup-activeUser')
     const newUser = localStorage.getItem(`${groupId}-newUser`)
@@ -84,13 +95,46 @@ export function ExpenseList({
     }
   }, [groupId, participants])
 
-  const getParticipant = (id: string) => participants.find((p) => p.id === id)
-  const router = useRouter()
+  useEffect(() => {
+    const fetchNextPage = async () => {
+      setIsFetching(true)
+
+      const newExpenses = await getGroupExpensesAction(groupId, {
+        offset: dataIndex,
+        length: dataLen,
+      })
+
+      if (newExpenses !== null) {
+        const exp = expenses.concat(newExpenses)
+        setExpenses(exp)
+        setHasMoreData(exp.length < expenseCount)
+        setDataIndex(dataIndex + dataLen)
+        setDataLen(Math.ceil(1.5 * dataLen))
+      }
+
+      setTimeout(() => setIsFetching(false), 500)
+    }
+
+    if (inView && hasMoreData && !isFetching) fetchNextPage()
+  }, [
+    dataIndex,
+    dataLen,
+    expenseCount,
+    expenses,
+    groupId,
+    hasMoreData,
+    inView,
+    isFetching,
+  ])
+
+  const groupedExpensesByDate = useMemo(
+    () => getGroupedExpensesByDate(expenses),
+    [expenses],
+  )
 
-  const groupedExpensesByDate = getGroupedExpensesByDate(expenses)
   return expenses.length > 0 ? (
     <>
-      <SearchBar onChange={(e) => setSearchText(e.target.value)} />
+      <SearchBar onValueChange={(value) => setSearchText(value)} />
       {Object.values(EXPENSE_GROUPS).map((expenseGroup: string) => {
         let groupExpenses = groupedExpensesByDate[expenseGroup]
         if (!groupExpenses) return null
@@ -110,73 +154,33 @@ export function ExpenseList({
             >
               {expenseGroup}
             </div>
-            {groupExpenses.map((expense: any) => (
-              <div
+            {groupExpenses.map((expense) => (
+              <ExpenseCard
                 key={expense.id}
-                className={cn(
-                  'flex justify-between sm:mx-6 px-4 sm:rounded-lg sm:pr-2 sm:pl-4 py-4 text-sm cursor-pointer hover:bg-accent gap-1 items-stretch',
-                  expense.isReimbursement && 'italic',
-                )}
-                onClick={() => {
-                  router.push(`/groups/${groupId}/expenses/${expense.id}/edit`)
-                }}
-              >
-                <CategoryIcon
-                  category={expense.category}
-                  className="w-4 h-4 mr-2 mt-0.5 text-muted-foreground"
-                />
-                <div className="flex-1">
-                  <div
-                    className={cn('mb-1', expense.isReimbursement && 'italic')}
-                  >
-                    {expense.title}
-                  </div>
-                  <div className="text-xs text-muted-foreground">
-                    Paid by{' '}
-                    <strong>{getParticipant(expense.paidById)?.name}</strong>{' '}
-                    for{' '}
-                    {expense.paidFor.map((paidFor: any, index: number) => (
-                      <Fragment key={index}>
-                        {index !== 0 && <>, </>}
-                        <strong>
-                          {
-                            participants.find(
-                              (p) => p.id === paidFor.participantId,
-                            )?.name
-                          }
-                        </strong>
-                      </Fragment>
-                    ))}
-                  </div>
-                </div>
-                <div className="flex flex-col justify-between items-end">
-                  <div
-                    className={cn(
-                      'tabular-nums whitespace-nowrap',
-                      expense.isReimbursement ? 'italic' : 'font-bold',
-                    )}
-                  >
-                    {formatCurrency(currency, expense.amount)}
-                  </div>
-                  <div className="text-xs text-muted-foreground">
-                    {formatExpenseDate(expense.expenseDate)}
-                  </div>
-                </div>
-                <Button
-                  size="icon"
-                  variant="link"
-                  className="self-center hidden sm:flex"
-                  asChild
-                >
-                  <Link href={`/groups/${groupId}/expenses/${expense.id}/edit`}>
-                    <ChevronRight className="w-4 h-4" />
-                  </Link>
-                </Button>
-              </div>
+                expense={expense}
+                currency={currency}
+                groupId={groupId}
+              />
             ))}
           </div>
         )
       })}
+      {expenses.length < expenseCount &&
+        [0, 1, 2].map((i) => (
+          <div
+            key={i}
+            className="border-t flex justify-between items-center px-6 py-4 text-sm"
+            ref={i === 0 ? ref : undefined}
+          >
+            <div className="flex flex-col gap-2">
+              <Skeleton className="h-4 w-16 rounded-full" />
+              <Skeleton className="h-4 w-32 rounded-full" />
+            </div>
+            <div>
+              <Skeleton className="h-4 w-16 rounded-full" />
+            </div>
+          </div>
+        ))}
     </>
   ) : (
     <p className="px-6 text-sm py-6">

src/app/groups/[groupId]/expenses/export/json/route.ts

@@ -1,4 +1,4 @@
-import { getPrisma } from '@/lib/prisma'
+import { prisma } from '@/lib/prisma'
 import contentDisposition from 'content-disposition'
 import { NextResponse } from 'next/server'
 
@@ -6,7 +6,6 @@ export async function GET(
   req: Request,
   { params: { groupId } }: { params: { groupId: string } },
 ) {
-  const prisma = await getPrisma()
   const group = await prisma.group.findUnique({
     where: { id: groupId },
     select: {

src/app/groups/[groupId]/expenses/page.tsx

@@ -11,7 +11,11 @@ import {
   CardTitle,
 } from '@/components/ui/card'
 import { Skeleton } from '@/components/ui/skeleton'
-import { getCategories, getGroupExpenses } from '@/lib/api'
+import {
+  getCategories,
+  getGroupExpenseCount,
+  getGroupExpenses,
+} from '@/lib/api'
 import { env } from '@/lib/env'
 import { Download, Plus } from 'lucide-react'
 import { Metadata } from 'next'
@@ -51,6 +55,7 @@ export default async function GroupExpensesPage({
                 prefetch={false}
                 href={`/groups/${groupId}/expenses/export/json`}
                 target="_blank"
+                title="Export to JSON"
               >
                 <Download className="w-4 h-4" />
               </Link>
@@ -63,7 +68,10 @@ export default async function GroupExpensesPage({
               />
             )}
             <Button asChild size="icon">
-              <Link href={`/groups/${groupId}/expenses/create`}>
+              <Link
+                href={`/groups/${groupId}/expenses/create`}
+                title="Create expense"
+              >
                 <Plus className="w-4 h-4" />
               </Link>
             </Button>
@@ -87,7 +95,7 @@ export default async function GroupExpensesPage({
               </div>
             ))}
           >
-            <Expenses groupId={groupId} />
+            <Expenses group={group} />
           </Suspense>
         </CardContent>
       </Card>
@@ -97,14 +105,22 @@ export default async function GroupExpensesPage({
   )
 }
 
-async function Expenses({ groupId }: { groupId: string }) {
-  const group = await cached.getGroup(groupId)
-  if (!group) notFound()
-  const expenses = await getGroupExpenses(group.id)
+type Props = {
+  group: NonNullable<Awaited<ReturnType<typeof cached.getGroup>>>
+}
+
+async function Expenses({ group }: Props) {
+  const expenseCount = await getGroupExpenseCount(group.id)
+
+  const expenses = await getGroupExpenses(group.id, {
+    offset: 0,
+    length: 200,
+  })
 
   return (
     <ExpenseList
-      expenses={expenses}
+      expensesFirstPage={expenses}
+      expenseCount={expenseCount}
       groupId={group.id}
       currency={group.currency}
       participants={group.participants}

src/app/groups/[groupId]/group-tabs.tsx

@@ -15,7 +15,7 @@ export function GroupTabs({ groupId }: Props) {
   return (
     <Tabs
       value={value}
-      className="[&>*]:border"
+      className="[&>*]:border overflow-x-auto"
       onValueChange={(value) => {
         router.push(`/groups/${groupId}/${value}`)
       }}
@@ -23,6 +23,8 @@ export function GroupTabs({ groupId }: Props) {
       <TabsList>
         <TabsTrigger value="expenses">Expenses</TabsTrigger>
         <TabsTrigger value="balances">Balances</TabsTrigger>
+        <TabsTrigger value="stats">Stats</TabsTrigger>
+        <TabsTrigger value="activity">Activity</TabsTrigger>
         <TabsTrigger value="edit">Settings</TabsTrigger>
       </TabsList>
     </Tabs>

src/app/groups/[groupId]/layout.tsx

@@ -35,7 +35,7 @@ export default async function GroupLayout({
 
   return (
     <>
-      <div className="flex flex-col sm:flex-row justify-between sm:items-center gap-3">
+      <div className="flex flex-col justify-between gap-3">
         <h1 className="font-bold text-2xl">
           <Link href={`/groups/${groupId}`}>{group.name}</Link>
         </h1>

src/app/groups/[groupId]/share-button.tsx

@@ -23,7 +23,7 @@ export function ShareButton({ group }: Props) {
   return (
     <Popover>
       <PopoverTrigger asChild>
-        <Button size="icon">
+        <Button title="Share" size="icon" className="flex-shrink-0">
           <Share className="w-4 h-4" />
         </Button>
       </PopoverTrigger>

src/app/groups/[groupId]/stats/page.tsx

@@ -0,0 +1,49 @@
+import { cached } from '@/app/cached-functions'
+import { Totals } from '@/app/groups/[groupId]/stats/totals'
+import {
+  Card,
+  CardContent,
+  CardDescription,
+  CardHeader,
+  CardTitle,
+} from '@/components/ui/card'
+import { getGroupExpenses } from '@/lib/api'
+import { getTotalGroupSpending } from '@/lib/totals'
+import { Metadata } from 'next'
+import { notFound } from 'next/navigation'
+
+export const metadata: Metadata = {
+  title: 'Totals',
+}
+
+export default async function TotalsPage({
+  params: { groupId },
+}: {
+  params: { groupId: string }
+}) {
+  const group = await cached.getGroup(groupId)
+  if (!group) notFound()
+
+  const expenses = await getGroupExpenses(groupId)
+  const totalGroupSpendings = getTotalGroupSpending(expenses)
+
+  return (
+    <>
+      <Card className="mb-4">
+        <CardHeader>
+          <CardTitle>Totals</CardTitle>
+          <CardDescription>
+            Spending summary of the entire group.
+          </CardDescription>
+        </CardHeader>
+        <CardContent className="flex flex-col space-y-4">
+          <Totals
+            group={group}
+            expenses={expenses}
+            totalGroupSpendings={totalGroupSpendings}
+          />
+        </CardContent>
+      </Card>
+    </>
+  )
+}

src/app/groups/[groupId]/stats/totals-group-spending.tsx

@@ -0,0 +1,18 @@
+import { formatCurrency } from '@/lib/utils'
+
+type Props = {
+  totalGroupSpendings: number
+  currency: string
+}
+
+export function TotalsGroupSpending({ totalGroupSpendings, currency }: Props) {
+  const balance = totalGroupSpendings < 0 ? 'earnings' : 'spendings'
+  return (
+    <div>
+      <div className="text-muted-foreground">Total group {balance}</div>
+      <div className="text-lg">
+        {formatCurrency(currency, Math.abs(totalGroupSpendings))}
+      </div>
+    </div>
+  )
+}

src/app/groups/[groupId]/stats/totals-your-share.tsx

@@ -0,0 +1,39 @@
+'use client'
+import { getGroup, getGroupExpenses } from '@/lib/api'
+import { getTotalActiveUserShare } from '@/lib/totals'
+import { cn, formatCurrency } from '@/lib/utils'
+import { useEffect, useState } from 'react'
+
+type Props = {
+  group: NonNullable<Awaited<ReturnType<typeof getGroup>>>
+  expenses: NonNullable<Awaited<ReturnType<typeof getGroupExpenses>>>
+}
+
+export function TotalsYourShare({ group, expenses }: Props) {
+  const [activeUser, setActiveUser] = useState('')
+
+  useEffect(() => {
+    const activeUser = localStorage.getItem(`${group.id}-activeUser`)
+    if (activeUser) setActiveUser(activeUser)
+  }, [group, expenses])
+
+  const totalActiveUserShare =
+    activeUser === '' || activeUser === 'None'
+      ? 0
+      : getTotalActiveUserShare(activeUser, expenses)
+  const currency = group.currency
+
+  return (
+    <div>
+      <div className="text-muted-foreground">Your total share</div>
+      <div
+        className={cn(
+          'text-lg',
+          totalActiveUserShare < 0 ? 'text-green-600' : 'text-red-600',
+        )}
+      >
+        {formatCurrency(currency, Math.abs(totalActiveUserShare))}
+      </div>
+    </div>
+  )
+}

src/app/groups/[groupId]/stats/totals-your-spending.tsx

@@ -0,0 +1,36 @@
+'use client'
+import { getGroup, getGroupExpenses } from '@/lib/api'
+import { useActiveUser } from '@/lib/hooks'
+import { getTotalActiveUserPaidFor } from '@/lib/totals'
+import { cn, formatCurrency } from '@/lib/utils'
+
+type Props = {
+  group: NonNullable<Awaited<ReturnType<typeof getGroup>>>
+  expenses: NonNullable<Awaited<ReturnType<typeof getGroupExpenses>>>
+}
+
+export function TotalsYourSpendings({ group, expenses }: Props) {
+  const activeUser = useActiveUser(group.id)
+
+  const totalYourSpendings =
+    activeUser === '' || activeUser === 'None'
+      ? 0
+      : getTotalActiveUserPaidFor(activeUser, expenses)
+  const currency = group.currency
+  const balance = totalYourSpendings < 0 ? 'earnings' : 'spendings'
+
+  return (
+    <div>
+      <div className="text-muted-foreground">Your total {balance}</div>
+
+      <div
+        className={cn(
+          'text-lg',
+          totalYourSpendings < 0 ? 'text-green-600' : 'text-red-600',
+        )}
+      >
+        {formatCurrency(currency, Math.abs(totalYourSpendings))}
+      </div>
+    </div>
+  )
+}

src/app/groups/[groupId]/stats/totals.tsx

@@ -0,0 +1,34 @@
+'use client'
+import { TotalsGroupSpending } from '@/app/groups/[groupId]/stats/totals-group-spending'
+import { TotalsYourShare } from '@/app/groups/[groupId]/stats/totals-your-share'
+import { TotalsYourSpendings } from '@/app/groups/[groupId]/stats/totals-your-spending'
+import { getGroup, getGroupExpenses } from '@/lib/api'
+import { useActiveUser } from '@/lib/hooks'
+
+export function Totals({
+  group,
+  expenses,
+  totalGroupSpendings,
+}: {
+  group: NonNullable<Awaited<ReturnType<typeof getGroup>>>
+  expenses: NonNullable<Awaited<ReturnType<typeof getGroupExpenses>>>
+  totalGroupSpendings: number
+}) {
+  const activeUser = useActiveUser(group.id)
+  console.log('activeUser', activeUser)
+
+  return (
+    <>
+      <TotalsGroupSpending
+        totalGroupSpendings={totalGroupSpendings}
+        currency={group.currency}
+      />
+      {activeUser && activeUser !== 'None' && (
+        <>
+          <TotalsYourSpendings group={group} expenses={expenses} />
+          <TotalsYourShare group={group} expenses={expenses} />
+        </>
+      )}
+    </>
+  )
+}

src/components/delete-popup.tsx

@@ -0,0 +1,47 @@
+'use client'
+
+import { Trash2 } from 'lucide-react'
+import { AsyncButton } from './async-button'
+import { Button } from './ui/button'
+import {
+  Dialog,
+  DialogClose,
+  DialogContent,
+  DialogDescription,
+  DialogFooter,
+  DialogTitle,
+  DialogTrigger,
+} from './ui/dialog'
+
+export function DeletePopup({ onDelete }: { onDelete: () => Promise<void> }) {
+  return (
+    <Dialog>
+      <DialogTrigger asChild>
+        <Button variant="destructive">
+          <Trash2 className="w-4 h-4 mr-2" />
+          Delete
+        </Button>
+      </DialogTrigger>
+      <DialogContent>
+        <DialogTitle>Delete this expense?</DialogTitle>
+        <DialogDescription>
+          Do you really want to delete this expense? This action is
+          irreversible.
+        </DialogDescription>
+        <DialogFooter className="flex flex-col gap-2">
+          <AsyncButton
+            type="button"
+            variant="destructive"
+            loadingContent="Deleting…"
+            action={onDelete}
+          >
+            Yes
+          </AsyncButton>
+          <DialogClose asChild>
+            <Button variant={'secondary'}>Cancel</Button>
+          </DialogClose>
+        </DialogFooter>
+      </DialogContent>
+    </Dialog>
+  )
+}

src/components/expense-form.tsx

@@ -1,5 +1,4 @@
 'use client'
-import { AsyncButton } from '@/components/async-button'
 import { CategorySelector } from '@/components/category-selector'
 import { ExpenseDocumentsInput } from '@/components/expense-documents-input'
 import { SubmitButton } from '@/components/submit-button'
@@ -35,22 +34,116 @@ import {
   SelectValue,
 } from '@/components/ui/select'
 import { getCategories, getExpense, getGroup, randomId } from '@/lib/api'
-import { ExpenseFormValues, expenseFormSchema } from '@/lib/schemas'
+import { RuntimeFeatureFlags } from '@/lib/featureFlags'
+import { useActiveUser } from '@/lib/hooks'
+import {
+  ExpenseFormValues,
+  SplittingOptions,
+  expenseFormSchema,
+} from '@/lib/schemas'
 import { cn } from '@/lib/utils'
 import { zodResolver } from '@hookform/resolvers/zod'
-import { Save, Trash2 } from 'lucide-react'
+import { Save } from 'lucide-react'
+import Link from 'next/link'
 import { useSearchParams } from 'next/navigation'
 import { useState } from 'react'
 import { useForm } from 'react-hook-form'
 import { match } from 'ts-pattern'
+import { DeletePopup } from './delete-popup'
 import { extractCategoryFromTitle } from './expense-form-actions'
+import { Textarea } from './ui/textarea'
 
 export type Props = {
   group: NonNullable<Awaited<ReturnType<typeof getGroup>>>
   expense?: NonNullable<Awaited<ReturnType<typeof getExpense>>>
   categories: NonNullable<Awaited<ReturnType<typeof getCategories>>>
-  onSubmit: (values: ExpenseFormValues) => Promise<void>
-  onDelete?: () => Promise<void>
+  onSubmit: (values: ExpenseFormValues, participantId?: string) => Promise<void>
+  onDelete?: (participantId?: string) => Promise<void>
+  runtimeFeatureFlags: RuntimeFeatureFlags
+}
+
+const enforceCurrencyPattern = (value: string) =>
+  value
+    .replace(/^\s*-/, '_') // replace leading minus with _
+    .replace(/[.,]/, '#') // replace first comma with #
+    .replace(/[-.,]/g, '') // remove other minus and commas characters
+    .replace(/_/, '-') // change back _ to minus
+    .replace(/#/, '.') // change back # to dot
+    .replace(/[^-\d.]/g, '') // remove all non-numeric characters
+
+const capitalize = (value: string) =>
+  value.charAt(0).toUpperCase() + value.slice(1)
+
+const getDefaultSplittingOptions = (group: Props['group']) => {
+  const defaultValue = {
+    splitMode: 'EVENLY' as const,
+    paidFor: group.participants.map(({ id }) => ({
+      participant: id,
+      shares: '1' as unknown as number,
+    })),
+  }
+
+  if (typeof localStorage === 'undefined') return defaultValue
+  const defaultSplitMode = localStorage.getItem(
+    `${group.id}-defaultSplittingOptions`,
+  )
+  if (defaultSplitMode === null) return defaultValue
+  const parsedDefaultSplitMode = JSON.parse(
+    defaultSplitMode,
+  ) as SplittingOptions
+
+  if (parsedDefaultSplitMode.paidFor === null) {
+    parsedDefaultSplitMode.paidFor = defaultValue.paidFor
+  }
+
+  // if there is a participant in the default options that does not exist anymore,
+  // remove the stale default splitting options
+  for (const parsedPaidFor of parsedDefaultSplitMode.paidFor) {
+    if (
+      !group.participants.some(({ id }) => id === parsedPaidFor.participant)
+    ) {
+      localStorage.removeItem(`${group.id}-defaultSplittingOptions`)
+      return defaultValue
+    }
+  }
+
+  return {
+    splitMode: parsedDefaultSplitMode.splitMode,
+    paidFor: parsedDefaultSplitMode.paidFor.map((paidFor) => ({
+      participant: paidFor.participant,
+      shares: String(paidFor.shares / 100) as unknown as number,
+    })),
+  }
+}
+
+async function persistDefaultSplittingOptions(
+  groupId: string,
+  expenseFormValues: ExpenseFormValues,
+) {
+  if (localStorage && expenseFormValues.saveDefaultSplittingOptions) {
+    const computePaidFor = (): SplittingOptions['paidFor'] => {
+      if (expenseFormValues.splitMode === 'EVENLY') {
+        return expenseFormValues.paidFor.map(({ participant }) => ({
+          participant,
+          shares: '100' as unknown as number,
+        }))
+      } else if (expenseFormValues.splitMode === 'BY_AMOUNT') {
+        return null
+      } else {
+        return expenseFormValues.paidFor
+      }
+    }
+
+    const splittingOptions = {
+      splitMode: expenseFormValues.splitMode,
+      paidFor: computePaidFor(),
+    } satisfies SplittingOptions
+
+    localStorage.setItem(
+      `${groupId}-defaultSplittingOptions`,
+      JSON.stringify(splittingOptions),
+    )
+  }
 }
 
 export function ExpenseForm({
@@ -59,18 +152,20 @@ export function ExpenseForm({
   categories,
   onSubmit,
   onDelete,
+  runtimeFeatureFlags,
 }: Props) {
   const isCreate = expense === undefined
   const searchParams = useSearchParams()
   const getSelectedPayer = (field?: { value: string }) => {
     if (isCreate && typeof window !== 'undefined') {
       const activeUser = localStorage.getItem(`${group.id}-activeUser`)
-      if (activeUser && activeUser !== 'None') {
+      if (activeUser && activeUser !== 'None' && field?.value === undefined) {
         return activeUser
       }
     }
     return field?.value
   }
+  const defaultSplittingOptions = getDefaultSplittingOptions(group)
   const form = useForm<ExpenseFormValues>({
     resolver: zodResolver(expenseFormSchema),
     defaultValues: expense
@@ -85,8 +180,10 @@ export function ExpenseForm({
             shares: String(shares / 100) as unknown as number,
           })),
           splitMode: expense.splitMode,
+          saveDefaultSplittingOptions: false,
           isReimbursement: expense.isReimbursement,
           documents: expense.documents,
+          notes: expense.notes ?? '',
         }
       : searchParams.get('reimbursement')
       ? {
@@ -99,12 +196,17 @@ export function ExpenseForm({
           paidBy: searchParams.get('from') ?? undefined,
           paidFor: [
             searchParams.get('to')
-              ? { participant: searchParams.get('to')!, shares: 1 }
+              ? {
+                  participant: searchParams.get('to')!,
+                  shares: '1' as unknown as number,
+                }
               : undefined,
           ],
           isReimbursement: true,
-          splitMode: 'EVENLY',
+          splitMode: defaultSplittingOptions.splitMode,
+          saveDefaultSplittingOptions: false,
           documents: [],
+          notes: '',
         }
       : {
           title: searchParams.get('title') ?? '',
@@ -116,13 +218,11 @@ export function ExpenseForm({
             ? Number(searchParams.get('categoryId'))
             : 0, // category with Id 0 is General
           // paid for all, split evenly
-          paidFor: group.participants.map(({ id }) => ({
-            participant: id,
-            shares: 1,
-          })),
+          paidFor: defaultSplittingOptions.paidFor,
           paidBy: getSelectedPayer(),
           isReimbursement: false,
-          splitMode: 'EVENLY',
+          splitMode: defaultSplittingOptions.splitMode,
+          saveDefaultSplittingOptions: false,
           documents: searchParams.get('imageUrl')
             ? [
                 {
@@ -133,18 +233,27 @@ export function ExpenseForm({
                 },
               ]
             : [],
+          notes: '',
         },
   })
   const [isCategoryLoading, setCategoryLoading] = useState(false)
+  const activeUserId = useActiveUser(group.id)
+
+  const submit = async (values: ExpenseFormValues) => {
+    await persistDefaultSplittingOptions(group.id, values)
+    return onSubmit(values, activeUserId ?? undefined)
+  }
+
+  const [isIncome, setIsIncome] = useState(Number(form.getValues().amount) < 0)
+  const sExpense = isIncome ? 'income' : 'expense'
+  const sPaid = isIncome ? 'received' : 'paid'
 
   return (
     <Form {...form}>
-      <form onSubmit={form.handleSubmit((values) => onSubmit(values))}>
+      <form onSubmit={form.handleSubmit(submit)}>
         <Card>
           <CardHeader>
-            <CardTitle>
-              {isCreate ? <>Create expense</> : <>Edit expense</>}
-            </CardTitle>
+            <CardTitle>{(isCreate ? 'Create ' : 'Edit ') + sExpense}</CardTitle>
           </CardHeader>
           <CardContent className="grid sm:grid-cols-2 gap-6">
             <FormField
@@ -152,7 +261,7 @@ export function ExpenseForm({
               name="title"
               render={({ field }) => (
                 <FormItem className="">
-                  <FormLabel>Expense title</FormLabel>
+                  <FormLabel>{capitalize(sExpense)} title</FormLabel>
                   <FormControl>
                     <Input
                       placeholder="Monday evening restaurant"
@@ -160,7 +269,7 @@ export function ExpenseForm({
                       {...field}
                       onBlur={async () => {
                         field.onBlur() // avoid skipping other blur event listeners since we overwrite `field`
-                        if (process.env.NEXT_PUBLIC_ENABLE_CATEGORY_EXTRACT) {
+                        if (runtimeFeatureFlags.enableCategoryExtract) {
                           setCategoryLoading(true)
                           const { categoryId } = await extractCategoryFromTitle(
                             field.value,
@@ -172,7 +281,7 @@ export function ExpenseForm({
                     />
                   </FormControl>
                   <FormDescription>
-                    Enter a description for the expense.
+                    Enter a description for the {sExpense}.
                   </FormDescription>
                   <FormMessage />
                 </FormItem>
@@ -184,7 +293,7 @@ export function ExpenseForm({
               name="expenseDate"
               render={({ field }) => (
                 <FormItem className="sm:order-1">
-                  <FormLabel>Expense date</FormLabel>
+                  <FormLabel>{capitalize(sExpense)} date</FormLabel>
                   <FormControl>
                     <Input
                       className="date-base"
@@ -196,7 +305,7 @@ export function ExpenseForm({
                     />
                   </FormControl>
                   <FormDescription>
-                    Enter the date the expense was made.
+                    Enter the date the {sExpense} was {sPaid}.
                   </FormDescription>
                   <FormMessage />
                 </FormItem>
@@ -206,7 +315,7 @@ export function ExpenseForm({
             <FormField
               control={form.control}
               name="amount"
-              render={({ field }) => (
+              render={({ field: { onChange, ...field } }) => (
                 <FormItem className="sm:order-3">
                   <FormLabel>Amount</FormLabel>
                   <div className="flex items-baseline gap-2">
@@ -214,33 +323,46 @@ export function ExpenseForm({
                     <FormControl>
                       <Input
                         className="text-base max-w-[120px]"
-                        type="number"
+                        type="text"
                         inputMode="decimal"
-                        step={0.01}
                         placeholder="0.00"
+                        onChange={(event) => {
+                          const v = enforceCurrencyPattern(event.target.value)
+                          const income = Number(v) < 0
+                          setIsIncome(income)
+                          if (income) form.setValue('isReimbursement', false)
+                          onChange(v)
+                        }}
+                        onFocus={(e) => {
+                          // we're adding a small delay to get around safaris issue with onMouseUp deselecting things again
+                          const target = e.currentTarget
+                          setTimeout(() => target.select(), 1)
+                        }}
                         {...field}
                       />
                     </FormControl>
                   </div>
                   <FormMessage />
 
-                  <FormField
-                    control={form.control}
-                    name="isReimbursement"
-                    render={({ field }) => (
-                      <FormItem className="flex flex-row gap-2 items-center space-y-0 pt-2">
-                        <FormControl>
-                          <Checkbox
-                            checked={field.value}
-                            onCheckedChange={field.onChange}
-                          />
-                        </FormControl>
-                        <div>
-                          <FormLabel>This is a reimbursement</FormLabel>
-                        </div>
-                      </FormItem>
-                    )}
-                  />
+                  {!isIncome && (
+                    <FormField
+                      control={form.control}
+                      name="isReimbursement"
+                      render={({ field }) => (
+                        <FormItem className="flex flex-row gap-2 items-center space-y-0 pt-2">
+                          <FormControl>
+                            <Checkbox
+                              checked={field.value}
+                              onCheckedChange={field.onChange}
+                            />
+                          </FormControl>
+                          <div>
+                            <FormLabel>This is a reimbursement</FormLabel>
+                          </div>
+                        </FormItem>
+                      )}
+                    />
+                  )}
                 </FormItem>
               )}
             />
@@ -260,7 +382,7 @@ export function ExpenseForm({
                     isLoading={isCategoryLoading}
                   />
                   <FormDescription>
-                    Select the expense category.
+                    Select the {sExpense} category.
                   </FormDescription>
                   <FormMessage />
                 </FormItem>
@@ -272,7 +394,7 @@ export function ExpenseForm({
               name="paidBy"
               render={({ field }) => (
                 <FormItem className="sm:order-5">
-                  <FormLabel>Paid by</FormLabel>
+                  <FormLabel>{capitalize(sPaid)} by</FormLabel>
                   <Select
                     onValueChange={field.onChange}
                     defaultValue={getSelectedPayer(field)}
@@ -289,19 +411,31 @@ export function ExpenseForm({
                     </SelectContent>
                   </Select>
                   <FormDescription>
-                    Select the participant who paid the expense.
+                    Select the participant who {sPaid} the {sExpense}.
                   </FormDescription>
                   <FormMessage />
                 </FormItem>
               )}
             />
+            <FormField
+              control={form.control}
+              name="notes"
+              render={({ field }) => (
+                <FormItem className="sm:order-6">
+                  <FormLabel>Notes</FormLabel>
+                  <FormControl>
+                    <Textarea className="text-base" {...field} />
+                  </FormControl>
+                </FormItem>
+              )}
+            />
           </CardContent>
         </Card>
 
         <Card className="mt-4">
           <CardHeader>
             <CardTitle className="flex justify-between">
-              <span>Paid for</span>
+              <span>{capitalize(sPaid)} for</span>
               <Button
                 variant="link"
                 type="button"
@@ -334,7 +468,7 @@ export function ExpenseForm({
               </Button>
             </CardTitle>
             <CardDescription>
-              Select who the expense was paid for.
+              Select who the {sExpense} was {sPaid} for.
             </CardDescription>
           </CardHeader>
           <CardContent>
@@ -423,7 +557,7 @@ export function ExpenseForm({
                                               ),
                                             )}
                                             className="text-base w-[80px] -my-2"
-                                            type="number"
+                                            type="text"
                                             disabled={
                                               !field.value?.some(
                                                 ({ participant }) =>
@@ -443,7 +577,9 @@ export function ExpenseForm({
                                                     ? {
                                                         participant: id,
                                                         shares:
-                                                          event.target.value,
+                                                          enforceCurrencyPattern(
+                                                            event.target.value,
+                                                          ),
                                                       }
                                                     : p,
                                                 ),
@@ -486,7 +622,10 @@ export function ExpenseForm({
               )}
             />
 
-            <Collapsible className="mt-5">
+            <Collapsible
+              className="mt-5"
+              defaultOpen={form.getValues().splitMode !== 'EVENLY'}
+            >
               <CollapsibleTrigger asChild>
                 <Button variant="link" className="-mx-4">
                   Advanced splitting options…
@@ -498,7 +637,7 @@ export function ExpenseForm({
                     control={form.control}
                     name="splitMode"
                     render={({ field }) => (
-                      <FormItem className="sm:order-2">
+                      <FormItem>
                         <FormLabel>Split mode</FormLabel>
                         <FormControl>
                           <Select
@@ -529,25 +668,44 @@ export function ExpenseForm({
                           </Select>
                         </FormControl>
                         <FormDescription>
-                          Select how to split the expense.
+                          Select how to split the {sExpense}.
                         </FormDescription>
                       </FormItem>
                     )}
                   />
+                  <FormField
+                    control={form.control}
+                    name="saveDefaultSplittingOptions"
+                    render={({ field }) => (
+                      <FormItem className="flex flex-row gap-2 items-center space-y-0 pt-2">
+                        <FormControl>
+                          <Checkbox
+                            checked={field.value}
+                            onCheckedChange={field.onChange}
+                          />
+                        </FormControl>
+                        <div>
+                          <FormLabel>
+                            Save as default splitting options
+                          </FormLabel>
+                        </div>
+                      </FormItem>
+                    )}
+                  />
                 </div>
               </CollapsibleContent>
             </Collapsible>
           </CardContent>
         </Card>
 
-        {process.env.NEXT_PUBLIC_ENABLE_EXPENSE_DOCUMENTS && (
+        {runtimeFeatureFlags.enableExpenseDocuments && (
           <Card className="mt-4">
             <CardHeader>
               <CardTitle className="flex justify-between">
                 <span>Attach documents</span>
               </CardTitle>
               <CardDescription>
-                See and attach receipts to the expense.
+                See and attach receipts to the {sExpense}.
               </CardDescription>
             </CardHeader>
             <CardContent>
@@ -573,16 +731,13 @@ export function ExpenseForm({
             {isCreate ? <>Create</> : <>Save</>}
           </SubmitButton>
           {!isCreate && onDelete && (
-            <AsyncButton
-              type="button"
-              variant="destructive"
-              loadingContent="Deleting…"
-              action={onDelete}
-            >
-              <Trash2 className="w-4 h-4 mr-2" />
-              Delete
-            </AsyncButton>
+            <DeletePopup
+              onDelete={() => onDelete(activeUserId ?? undefined)}
+            ></DeletePopup>
           )}
+          <Button variant="ghost" asChild>
+            <Link href={`/groups/${group.id}`}>Cancel</Link>
+          </Button>
         </div>
       </form>
     </Form>

src/components/group-form.tsx

@@ -35,12 +35,16 @@ import { getGroup } from '@/lib/api'
 import { GroupFormValues, groupFormSchema } from '@/lib/schemas'
 import { zodResolver } from '@hookform/resolvers/zod'
 import { Save, Trash2 } from 'lucide-react'
+import Link from 'next/link'
 import { useEffect, useState } from 'react'
 import { useFieldArray, useForm } from 'react-hook-form'
 
 export type Props = {
   group?: NonNullable<Awaited<ReturnType<typeof getGroup>>>
-  onSubmit: (groupFormValues: GroupFormValues) => Promise<void>
+  onSubmit: (
+    groupFormValues: GroupFormValues,
+    participantId?: string,
+  ) => Promise<void>
   protectedParticipantIds?: string[]
 }
 
@@ -98,7 +102,11 @@ export function GroupForm({
     <Form {...form}>
       <form
         onSubmit={form.handleSubmit(async (values) => {
-          await onSubmit(values)
+          await onSubmit(
+            values,
+            group?.participants.find((p) => p.name === activeUser)?.id ??
+              undefined,
+          )
         })}
       >
         <Card className="mb-4">
@@ -172,7 +180,11 @@ export function GroupForm({
                         </FormLabel>
                         <FormControl>
                           <div className="flex gap-2">
-                            <Input className="text-base" {...field} />
+                            <Input
+                              className="text-base"
+                              {...field}
+                              placeholder="New"
+                            />
                             {item.id &&
                             protectedParticipantIds.includes(item.id) ? (
                               <HoverCard>
@@ -220,7 +232,7 @@ export function GroupForm({
             <Button
               variant="secondary"
               onClick={() => {
-                append({ name: 'New' })
+                append({ name: '' })
               }}
               type="button"
             >
@@ -272,13 +284,19 @@ export function GroupForm({
           </CardContent>
         </Card>
 
-        <SubmitButton
-          size="lg"
-          loadingContent={group ? 'Saving…' : 'Creating…'}
-          onClick={updateActiveUser}
-        >
-          <Save className="w-4 h-4 mr-2" /> {group ? <>Save</> : <> Create</>}
-        </SubmitButton>
+        <div className="flex mt-4 gap-2">
+          <SubmitButton
+            loadingContent={group ? 'Saving…' : 'Creating…'}
+            onClick={updateActiveUser}
+          >
+            <Save className="w-4 h-4 mr-2" /> {group ? <>Save</> : <> Create</>}
+          </SubmitButton>
+          {!group && (
+            <Button variant="ghost" asChild>
+              <Link href="/groups">Cancel</Link>
+            </Button>
+          )}
+        </div>
       </form>
     </Form>
   )

src/components/money.tsx

@@ -0,0 +1,31 @@
+'use client'
+import { cn, formatCurrency } from '@/lib/utils'
+
+type Props = {
+  currency: string
+  amount: number
+  bold?: boolean
+  colored?: boolean
+}
+
+export function Money({
+  currency,
+  amount,
+  bold = false,
+  colored = false,
+}: Props) {
+  return (
+    <span
+      className={cn(
+        colored && amount <= 1
+          ? 'text-red-600'
+          : colored && amount >= 1
+          ? 'text-green-600'
+          : '',
+        bold && 'font-bold',
+      )}
+    >
+      {formatCurrency(currency, amount)}
+    </span>
+  )
+}

src/components/ui/search-bar.tsx

@@ -1,33 +1,49 @@
-import * as React from "react"
+import * as React from 'react'
 
-import {Input} from "@/components/ui/input";
-import {cn} from "@/lib/utils";
-import {
-  Search
-} from 'lucide-react'
+import { Input } from '@/components/ui/input'
+import { cn } from '@/lib/utils'
+import { Search, XCircle } from 'lucide-react'
 
 export interface InputProps
-  extends React.InputHTMLAttributes<HTMLInputElement> {}
+  extends React.InputHTMLAttributes<HTMLInputElement> {
+  onValueChange?: (value: string) => void
+}
 
 const SearchBar = React.forwardRef<HTMLInputElement, InputProps>(
-  ({ className, type, ...props }, ref) => {
+  ({ className, type, onValueChange, ...props }, ref) => {
+    const [value, _setValue] = React.useState('')
+
+    const setValue = (v: string) => {
+      _setValue(v)
+      onValueChange && onValueChange(v)
+    }
+
     return (
       <div className="mx-4 sm:mx-6 flex relative">
         <Search className="absolute left-3 top-1/2 -translate-y-1/2 w-4 h-4 text-muted-foreground" />
         <Input
           type={type}
           className={cn(
-            "pl-10 text-sm focus:text-base bg-muted border-none text-muted-foreground",
-            className
+            'pl-10 text-sm focus:text-base bg-muted border-none text-muted-foreground',
+            className,
           )}
           ref={ref}
           placeholder="Search for an expense…"
+          value={value}
+          onChange={(e) => setValue(e.target.value)}
           {...props}
         />
+        <XCircle
+          className={cn(
+            'absolute right-3 top-1/2 -translate-y-1/2 w-4 h-4 cursor-pointer',
+            !value && 'hidden',
+          )}
+          onClick={() => setValue('')}
+        />
       </div>
     )
-  }
+  },
 )
-SearchBar.displayName = "SearchBar"
+SearchBar.displayName = 'SearchBar'
 
 export { SearchBar }

src/lib/api.ts

@@ -1,6 +1,6 @@
-import { getPrisma } from '@/lib/prisma'
+import { prisma } from '@/lib/prisma'
 import { ExpenseFormValues, GroupFormValues } from '@/lib/schemas'
-import { Expense } from '@prisma/client'
+import { ActivityType, Expense } from '@prisma/client'
 import { nanoid } from 'nanoid'
 
 export function randomId() {
@@ -8,7 +8,6 @@ export function randomId() {
 }
 
 export async function createGroup(groupFormValues: GroupFormValues) {
-  const prisma = await getPrisma()
   return prisma.group.create({
     data: {
       id: randomId(),
@@ -30,6 +29,7 @@ export async function createGroup(groupFormValues: GroupFormValues) {
 export async function createExpense(
   expenseFormValues: ExpenseFormValues,
   groupId: string,
+  participantId?: string,
 ): Promise<Expense> {
   const group = await getGroup(groupId)
   if (!group) throw new Error(`Invalid group ID: ${groupId}`)
@@ -42,10 +42,16 @@ export async function createExpense(
       throw new Error(`Invalid participant ID: ${participant}`)
   }
 
-  const prisma = await getPrisma()
+  const expenseId = randomId()
+  await logActivity(groupId, ActivityType.CREATE_EXPENSE, {
+    participantId,
+    expenseId,
+    data: expenseFormValues.title,
+  })
+
   return prisma.expense.create({
     data: {
-      id: randomId(),
+      id: expenseId,
       groupId,
       expenseDate: expenseFormValues.expenseDate,
       categoryId: expenseFormValues.category,
@@ -72,12 +78,23 @@ export async function createExpense(
           })),
         },
       },
+      notes: expenseFormValues.notes,
     },
   })
 }
 
-export async function deleteExpense(expenseId: string) {
-  const prisma = await getPrisma()
+export async function deleteExpense(
+  groupId: string,
+  expenseId: string,
+  participantId?: string,
+) {
+  const existingExpense = await getExpense(groupId, expenseId)
+  await logActivity(groupId, ActivityType.DELETE_EXPENSE, {
+    participantId,
+    expenseId,
+    data: existingExpense?.title,
+  })
+
   await prisma.expense.delete({
     where: { id: expenseId },
     include: { paidFor: true, paidBy: true },
@@ -89,15 +106,14 @@ export async function getGroupExpensesParticipants(groupId: string) {
   return Array.from(
     new Set(
       expenses.flatMap((e) => [
-        e.paidById,
-        ...e.paidFor.map((pf) => pf.participantId),
+        e.paidBy.id,
+        ...e.paidFor.map((pf) => pf.participant.id),
       ]),
     ),
   )
 }
 
 export async function getGroups(groupIds: string[]) {
-  const prisma = await getPrisma()
   return (
     await prisma.group.findMany({
       where: { id: { in: groupIds } },
@@ -113,6 +129,7 @@ export async function updateExpense(
   groupId: string,
   expenseId: string,
   expenseFormValues: ExpenseFormValues,
+  participantId?: string,
 ) {
   const group = await getGroup(groupId)
   if (!group) throw new Error(`Invalid group ID: ${groupId}`)
@@ -128,7 +145,12 @@ export async function updateExpense(
       throw new Error(`Invalid participant ID: ${participant}`)
   }
 
-  const prisma = await getPrisma()
+  await logActivity(groupId, ActivityType.UPDATE_EXPENSE, {
+    participantId,
+    expenseId,
+    data: expenseFormValues.title,
+  })
+
   return prisma.expense.update({
     where: { id: expenseId },
     data: {
@@ -185,6 +207,7 @@ export async function updateExpense(
             id: doc.id,
           })),
       },
+      notes: expenseFormValues.notes,
     },
   })
 }
@@ -192,11 +215,13 @@ export async function updateExpense(
 export async function updateGroup(
   groupId: string,
   groupFormValues: GroupFormValues,
+  participantId?: string,
 ) {
   const existingGroup = await getGroup(groupId)
   if (!existingGroup) throw new Error('Invalid group ID')
 
-  const prisma = await getPrisma()
+  await logActivity(groupId, ActivityType.UPDATE_GROUP, { participantId })
+
   return prisma.group.update({
     where: { id: groupId },
     data: {
@@ -228,7 +253,6 @@ export async function updateGroup(
 }
 
 export async function getGroup(groupId: string) {
-  const prisma = await getPrisma()
   return prisma.group.findUnique({
     where: { id: groupId },
     include: { participants: true },
@@ -236,27 +260,67 @@ export async function getGroup(groupId: string) {
 }
 
 export async function getCategories() {
-  const prisma = await getPrisma()
   return prisma.category.findMany()
 }
 
-export async function getGroupExpenses(groupId: string) {
-  const prisma = await getPrisma()
+export async function getGroupExpenses(
+  groupId: string,
+  options?: { offset: number; length: number },
+) {
   return prisma.expense.findMany({
-    where: { groupId },
-    include: {
-      paidFor: { include: { participant: true } },
-      paidBy: true,
+    select: {
+      amount: true,
       category: true,
+      createdAt: true,
+      expenseDate: true,
+      id: true,
+      isReimbursement: true,
+      paidBy: { select: { id: true, name: true } },
+      paidFor: {
+        select: {
+          participant: { select: { id: true, name: true } },
+          shares: true,
+        },
+      },
+      splitMode: true,
+      title: true,
     },
+    where: { groupId },
     orderBy: [{ expenseDate: 'desc' }, { createdAt: 'desc' }],
+    skip: options && options.offset,
+    take: options && options.length,
   })
 }
 
+export async function getGroupExpenseCount(groupId: string) {
+  return prisma.expense.count({ where: { groupId } })
+}
+
 export async function getExpense(groupId: string, expenseId: string) {
-  const prisma = await getPrisma()
   return prisma.expense.findUnique({
     where: { id: expenseId },
     include: { paidBy: true, paidFor: true, category: true, documents: true },
   })
 }
+
+export async function getActivities(groupId: string) {
+  return prisma.activity.findMany({
+    where: { groupId },
+    orderBy: [{ time: 'desc' }],
+  })
+}
+
+export async function logActivity(
+  groupId: string,
+  activityType: ActivityType,
+  extra?: { participantId?: string; expenseId?: string; data?: string },
+) {
+  return prisma.activity.create({
+    data: {
+      id: randomId(),
+      groupId,
+      activityType,
+      ...extra,
+    },
+  })
+}

src/lib/balances.ts

@@ -19,7 +19,7 @@ export function getBalances(
   const balances: Balances = {}
 
   for (const expense of expenses) {
-    const paidBy = expense.paidById
+    const paidBy = expense.paidBy.id
     const paidFors = expense.paidFor
 
     if (!balances[paidBy]) balances[paidBy] = { paid: 0, paidFor: 0, total: 0 }
@@ -31,8 +31,8 @@ export function getBalances(
     )
     let remaining = expense.amount
     paidFors.forEach((paidFor, index) => {
-      if (!balances[paidFor.participantId])
-        balances[paidFor.participantId] = { paid: 0, paidFor: 0, total: 0 }
+      if (!balances[paidFor.participant.id])
+        balances[paidFor.participant.id] = { paid: 0, paidFor: 0, total: 0 }
 
       const isLast = index === paidFors.length - 1
 
@@ -47,7 +47,7 @@ export function getBalances(
         ? remaining
         : (expense.amount * shares) / totalShares
       remaining -= dividedAmount
-      balances[paidFor.participantId].paidFor += dividedAmount
+      balances[paidFor.participant.id].paidFor += dividedAmount
     })
   }
 

src/lib/env.ts

@@ -1,5 +1,10 @@
 import { ZodIssueCode, z } from 'zod'
 
+const interpretEnvVarAsBool = (val: unknown): boolean => {
+  if (typeof val !== 'string') return false
+  return ['true', 'yes', '1', 'on'].includes(val.toLowerCase())
+}
+
 const envSchema = z
   .object({
     POSTGRES_URL_NON_POOLING: z.string().url(),
@@ -12,14 +17,23 @@ const envSchema = z
           ? `https://${process.env.VERCEL_URL}`
           : 'http://localhost:3000',
       ),
-    NEXT_PUBLIC_ENABLE_EXPENSE_DOCUMENTS: z.coerce.boolean().default(false),
+    NEXT_PUBLIC_ENABLE_EXPENSE_DOCUMENTS: z.preprocess(
+      interpretEnvVarAsBool,
+      z.boolean().default(false),
+    ),
     S3_UPLOAD_KEY: z.string().optional(),
     S3_UPLOAD_SECRET: z.string().optional(),
     S3_UPLOAD_BUCKET: z.string().optional(),
     S3_UPLOAD_REGION: z.string().optional(),
     S3_UPLOAD_ENDPOINT: z.string().optional(),
-    NEXT_PUBLIC_ENABLE_RECEIPT_EXTRACT: z.coerce.boolean().default(false),
-    NEXT_PUBLIC_ENABLE_CATEGORY_EXTRACT: z.coerce.boolean().default(false),
+    NEXT_PUBLIC_ENABLE_RECEIPT_EXTRACT: z.preprocess(
+      interpretEnvVarAsBool,
+      z.boolean().default(false),
+    ),
+    NEXT_PUBLIC_ENABLE_CATEGORY_EXTRACT: z.preprocess(
+      interpretEnvVarAsBool,
+      z.boolean().default(false),
+    ),
     OPENAI_API_KEY: z.string().optional(),
   })
   .superRefine((env, ctx) => {

src/lib/featureFlags.ts

@@ -0,0 +1,15 @@
+'use server'
+
+import { env } from './env'
+
+export async function getRuntimeFeatureFlags() {
+  return {
+    enableExpenseDocuments: env.NEXT_PUBLIC_ENABLE_EXPENSE_DOCUMENTS,
+    enableReceiptExtract: env.NEXT_PUBLIC_ENABLE_RECEIPT_EXTRACT,
+    enableCategoryExtract: env.NEXT_PUBLIC_ENABLE_CATEGORY_EXTRACT,
+  }
+}
+
+export type RuntimeFeatureFlags = Awaited<
+  ReturnType<typeof getRuntimeFeatureFlags>
+>

src/lib/hooks.ts

@@ -48,3 +48,17 @@ export function useBaseUrl() {
   }, [])
   return baseUrl
 }
+
+/**
+ * @returns The active user, or `null` until it is fetched from local storage
+ */
+export function useActiveUser(groupId: string) {
+  const [activeUser, setActiveUser] = useState<string | null>(null)
+
+  useEffect(() => {
+    const activeUser = localStorage.getItem(`${groupId}-activeUser`)
+    if (activeUser) setActiveUser(activeUser)
+  }, [groupId])
+
+  return activeUser
+}

src/lib/prisma.ts

@@ -1,20 +1,21 @@
 import { PrismaClient } from '@prisma/client'
 
-let prisma: PrismaClient
+declare const global: Global & { prisma?: PrismaClient }
 
-export async function getPrisma() {
+export let p: PrismaClient = undefined as any as PrismaClient
+
+if (typeof window === 'undefined') {
   // await delay(1000)
-  if (!prisma) {
-    if (process.env.NODE_ENV === 'production') {
-      prisma = new PrismaClient()
-    } else {
-      if (!(global as any).prisma) {
-        ;(global as any).prisma = new PrismaClient({
-          // log: [{ emit: 'stdout', level: 'query' }],
-        })
-      }
-      prisma = (global as any).prisma
+  if (process.env['NODE_ENV'] === 'production') {
+    p = new PrismaClient()
+  } else {
+    if (!global.prisma) {
+      global.prisma = new PrismaClient({
+        // log: [{ emit: 'stdout', level: 'query' }],
+      })
     }
+    p = global.prisma
   }
-  return prisma
 }
+
+export const prisma = p

src/lib/schemas.ts

@@ -51,8 +51,7 @@ export const expenseFormSchema = z
         [
           z.number(),
           z.string().transform((value, ctx) => {
-            const normalizedValue = value.replace(/,/g, '.')
-            const valueAsNumber = Number(normalizedValue)
+            const valueAsNumber = Number(value)
             if (Number.isNaN(valueAsNumber))
               ctx.addIssue({
                 code: z.ZodIssueCode.custom,
@@ -63,7 +62,7 @@ export const expenseFormSchema = z
         ],
         { required_error: 'You must enter an amount.' },
       )
-      .refine((amount) => amount >= 1, 'The amount must be higher than 0.01.')
+      .refine((amount) => amount != 1, 'The amount must not be zero.')
       .refine(
         (amount) => amount <= 10_000_000_00,
         'The amount must be lower than 10,000,000.',
@@ -106,6 +105,7 @@ export const expenseFormSchema = z
         Object.values(SplitMode) as any,
       )
       .default('EVENLY'),
+    saveDefaultSplittingOptions: z.boolean(),
     isReimbursement: z.boolean(),
     documents: z
       .array(
@@ -117,6 +117,7 @@ export const expenseFormSchema = z
         }),
       )
       .default([]),
+    notes: z.string().optional(),
   })
   .superRefine((expense, ctx) => {
     let sum = 0
@@ -161,3 +162,9 @@ export const expenseFormSchema = z
   })
 
 export type ExpenseFormValues = z.infer<typeof expenseFormSchema>
+
+export type SplittingOptions = {
+  // Used for saving default splitting options in localStorage
+  splitMode: SplitMode
+  paidFor: ExpenseFormValues['paidFor'] | null
+}

src/lib/totals.ts

@@ -0,0 +1,70 @@
+import { getGroupExpenses } from '@/lib/api'
+
+export function getTotalGroupSpending(
+  expenses: NonNullable<Awaited<ReturnType<typeof getGroupExpenses>>>,
+): number {
+  return expenses.reduce(
+    (total, expense) =>
+      expense.isReimbursement ? total : total + expense.amount,
+    0,
+  )
+}
+
+export function getTotalActiveUserPaidFor(
+  activeUserId: string | null,
+  expenses: NonNullable<Awaited<ReturnType<typeof getGroupExpenses>>>,
+): number {
+  return expenses.reduce(
+    (total, expense) =>
+      expense.paidBy.id === activeUserId && !expense.isReimbursement
+        ? total + expense.amount
+        : total,
+    0,
+  )
+}
+
+export function getTotalActiveUserShare(
+  activeUserId: string | null,
+  expenses: NonNullable<Awaited<ReturnType<typeof getGroupExpenses>>>,
+): number {
+  let total = 0
+
+  expenses.forEach((expense) => {
+    if (expense.isReimbursement) return
+
+    const paidFors = expense.paidFor
+    const userPaidFor = paidFors.find(
+      (paidFor) => paidFor.participant.id === activeUserId,
+    )
+
+    if (!userPaidFor) {
+      // If the active user is not involved in the expense, skip it
+      return
+    }
+
+    switch (expense.splitMode) {
+      case 'EVENLY':
+        // Divide the total expense evenly among all participants
+        total += expense.amount / paidFors.length
+        break
+      case 'BY_AMOUNT':
+        // Directly add the user's share if the split mode is BY_AMOUNT
+        total += userPaidFor.shares
+        break
+      case 'BY_PERCENTAGE':
+        // Calculate the user's share based on their percentage of the total expense
+        total += (expense.amount * userPaidFor.shares) / 10000 // Assuming shares are out of 10000 for percentage
+        break
+      case 'BY_SHARES':
+        // Calculate the user's share based on their shares relative to the total shares
+        const totalShares = paidFors.reduce(
+          (sum, paidFor) => sum + paidFor.shares,
+          0,
+        )
+        total += (expense.amount * userPaidFor.shares) / totalShares
+        break
+    }
+  })
+
+  return parseFloat(total.toFixed(2))
+}

src/lib/utils.ts

@@ -10,9 +10,15 @@ export function delay(ms: number) {
   return new Promise((resolve) => setTimeout(resolve, ms))
 }
 
-export function formatExpenseDate(date: Date) {
-  return date.toLocaleDateString('en-US', {
-    dateStyle: 'medium',
+export type DateTimeStyle = NonNullable<
+  ConstructorParameters<typeof Intl.DateTimeFormat>[1]
+>['dateStyle']
+export function formatDate(
+  date: Date,
+  options: { dateStyle?: DateTimeStyle; timeStyle?: DateTimeStyle } = {},
+) {
+  return date.toLocaleString('en-GB', {
+    ...options,
     timeZone: 'UTC',
   })
 }

src/scripts/migrate.ts

@@ -1,6 +1,6 @@
 // @ts-nocheck
 import { randomId } from '@/lib/api'
-import { getPrisma } from '@/lib/prisma'
+import { prisma } from '@/lib/prisma'
 import { Prisma } from '@prisma/client'
 import { Client } from 'pg'
 
@@ -8,8 +8,6 @@ process.env.NODE_TLS_REJECT_UNAUTHORIZED = '0'
 
 async function main() {
   withClient(async (client) => {
-    const prisma = await getPrisma()
-
     // console.log('Deleting all groups…')
     // await prisma.group.deleteMany({})