Fix/issues 7 8 9 expense ledger improvements

apps/backend/prisma/schema.prisma

@@ -57,6 +57,8 @@ model Group {
   name        String
   createdBy   String
   currency    String
+  defaultSplitType String?
+  defaultSplitConfig String?
   createdAt   DateTime      @default(now())
   creator     User          @relation("group_creator", fields: [createdBy], references: [id])
   members     GroupMember[]
@@ -93,6 +95,7 @@ model Expense {
   description      String
   totalAmountCents BigInt
   currency         String
+  category         String?
   createdAt        DateTime @default(now())
   group            Group    @relation(fields: [groupId], references: [id])
   payer            User     @relation("expense_payer", fields: [payerId], references: [id])
@@ -235,3 +238,5 @@ model Payment {
   @@index([receiverId])
   @@map("payments")
 }
+
+

apps/backend/src/expenses/dto/create-expense.dto.ts

@@ -1,6 +1,6 @@
-import { IsArray, IsIn, IsString, MinLength, ValidateNested } from 'class-validator';
+import { IsArray, IsIn, IsOptional, IsString, MinLength, ValidateNested } from 'class-validator';
 import { Transform, Type } from 'class-transformer';
-import { CreateExpenseRequestDto, CreateExpenseSplitDto } from '@fairshare/shared-types';
+import { CreateExpenseRequestDto, CreateExpenseSplitDto, EXPENSE_CATEGORIES } from '@fairshare/shared-types';
 import { sanitizeText } from '../../common/utils/sanitize.util';
 
 export class CreateExpenseSplitInputDto implements CreateExpenseSplitDto {
@@ -30,6 +30,11 @@ export class CreateExpenseDto implements CreateExpenseRequestDto {
   @IsIn(['USD', 'EUR', 'INR'])
   currency!: 'USD' | 'EUR' | 'INR';
 
+  @IsOptional()
+  @IsString()
+  @IsIn([...EXPENSE_CATEGORIES])
+  category?: (typeof EXPENSE_CATEGORIES)[number];
+
   @IsArray()
   @ValidateNested({ each: true })
   @Type(() => CreateExpenseSplitInputDto)

apps/backend/src/expenses/dto/update-expense.dto.ts

@@ -1,9 +1,14 @@
-import { IsOptional, IsString, MinLength } from 'class-validator';
-import { UpdateExpenseRequestDto } from '@fairshare/shared-types';
+import { IsIn, IsOptional, IsString, MinLength } from 'class-validator';
+import { EXPENSE_CATEGORIES, UpdateExpenseRequestDto } from '@fairshare/shared-types';
 
 export class UpdateExpenseDto implements UpdateExpenseRequestDto {
   @IsOptional()
   @IsString()
   @MinLength(2)
   description?: string;
+
+  @IsOptional()
+  @IsString()
+  @IsIn([...EXPENSE_CATEGORIES])
+  category?: (typeof EXPENSE_CATEGORIES)[number] | null;
 }

apps/backend/src/expenses/expenses.service.ts

@@ -73,6 +73,7 @@ export class ExpensesService {
           description: dto.description,
           totalAmountCents: totalAmount,
           currency: dto.currency,
+          category: dto.category ?? null,
         },
       });
 
@@ -105,6 +106,7 @@ export class ExpensesService {
           metadata: {
             payerId: dto.payerId,
             totalAmountCents: totalAmount.toString(),
+            category: dto.category ?? null,
           },
         },
       });
@@ -131,6 +133,7 @@ export class ExpensesService {
       expenseId: expense.id,
       payerId: expense.payerId,
       totalAmountCents: expense.totalAmountCents.toString(),
+      category: expense.category as ExpenseDto['category'],
     });
     incrementExpenseCreated(groupId);
 
@@ -180,6 +183,7 @@ export class ExpensesService {
       where: { id },
       data: {
         description: dto.description,
+        category: dto.category,
       },
       include: { splits: true },
     });
@@ -189,7 +193,7 @@ export class ExpensesService {
       actorUserId,
       type: 'expense_updated',
       entityId: expense.id,
-      metadata: { description: dto.description ?? null },
+      metadata: { description: dto.description ?? null, category: dto.category ?? null },
     });
 
     await this.redis.invalidateGroupCache(expense.groupId);
@@ -245,6 +249,7 @@ export class ExpensesService {
     description: string;
     totalAmountCents: bigint;
     currency: string;
+    category: string | null;
     createdAt: Date;
     splits: Array<{
       id: string;
@@ -260,6 +265,7 @@ export class ExpensesService {
       description: expense.description,
       totalAmountCents: expense.totalAmountCents.toString(),
       currency: expense.currency as 'USD' | 'EUR' | 'INR',
+      category: expense.category as ExpenseDto['category'],
       createdAt: expense.createdAt.toISOString(),
       splits: expense.splits.map((split) => ({
         id: split.id,
@@ -270,3 +276,4 @@ export class ExpensesService {
     };
   }
 }
+

apps/backend/src/groups/dto/update-group-default-split.dto.ts

@@ -0,0 +1,28 @@
+import { Type } from 'class-transformer';
+import { IsArray, IsIn, IsObject, IsOptional, IsString, ValidateNested } from 'class-validator';
+import { EXPENSE_SPLIT_TYPES, GroupDefaultSplitDto, UpdateGroupDefaultSplitRequestDto } from '@fairshare/shared-types';
+
+class GroupDefaultSplitPreferenceDto implements GroupDefaultSplitDto {
+  @IsString()
+  @IsIn([...EXPENSE_SPLIT_TYPES])
+  splitType!: (typeof EXPENSE_SPLIT_TYPES)[number];
+
+  @IsArray()
+  @IsString({ each: true })
+  participantUserIds!: string[];
+
+  @IsOptional()
+  @IsObject()
+  exactAmountsCentsByUser?: Record<string, string>;
+
+  @IsOptional()
+  @IsObject()
+  percentagesByUser?: Record<string, string>;
+}
+
+export class UpdateGroupDefaultSplitDto implements UpdateGroupDefaultSplitRequestDto {
+  @IsOptional()
+  @ValidateNested()
+  @Type(() => GroupDefaultSplitPreferenceDto)
+  defaultSplitPreference!: GroupDefaultSplitPreferenceDto | null;
+}

apps/backend/src/groups/groups.controller.ts

@@ -1,11 +1,12 @@
-import { Body, Controller, Get, Param, Post, UseGuards } from '@nestjs/common';
+import { Body, Controller, Get, Param, Patch, Post, UseGuards } from '@nestjs/common';
 import { Throttle } from '@nestjs/throttler';
 import { JwtAuthGuard } from '../auth/guards/jwt-auth.guard';
 import { CurrentUser } from '../common/decorators/current-user.decorator';
 import { JwtPayload } from '../auth/types/auth.types';
 import { GroupsService } from './groups.service';
 import { CreateGroupDto } from './dto/create-group.dto';
 import { InviteMemberDto } from './dto/invite-member.dto';
+import { UpdateGroupDefaultSplitDto } from './dto/update-group-default-split.dto';
 
 @Controller('groups')
 @UseGuards(JwtAuthGuard)
@@ -42,9 +43,14 @@ export class GroupsController {
     return this.groupsService.summary(id, user.sub);
   }
 
+  @Patch(':id/default-split')
+  updateDefaultSplit(@Param('id') id: string, @CurrentUser() user: JwtPayload, @Body() dto: UpdateGroupDefaultSplitDto) {
+    return this.groupsService.updateDefaultSplit(id, user.sub, dto);
+  }
+
   @Post(':id/invite')
   @Throttle({ default: { limit: 10, ttl: 60_000 } })
   invite(@Param('id') id: string, @CurrentUser() user: JwtPayload, @Body() dto: InviteMemberDto) {
     return this.groupsService.invite(id, user.sub, dto);
   }
-}
+}

apps/backend/src/groups/groups.service.ts

@@ -1,11 +1,12 @@
 import { ConflictException, ForbiddenException, Injectable, NotFoundException } from '@nestjs/common';
-import { GroupDto, GroupMemberSummaryDto, GroupSummaryDto } from '@fairshare/shared-types';
+import { GroupDefaultSplitDto, GroupDto, GroupMemberSummaryDto, GroupSummaryDto } from '@fairshare/shared-types';
 import { PrismaService } from '../common/prisma.service';
 import { RedisService } from '../redis/redis.service';
 import { NotificationsService } from '../notifications/notifications.service';
 import { RealtimeService } from '../realtime/realtime.service';
 import { CreateGroupDto } from './dto/create-group.dto';
 import { InviteMemberDto } from './dto/invite-member.dto';
+import { UpdateGroupDefaultSplitDto } from './dto/update-group-default-split.dto';
 
 @Injectable()
 export class GroupsService {
@@ -53,6 +54,7 @@ export class GroupsService {
       currency: group.currency as 'USD' | 'EUR' | 'INR',
       createdBy: group.createdBy,
       createdAt: group.createdAt.toISOString(),
+      defaultSplitPreference: null,
     };
   }
 
@@ -74,6 +76,7 @@ export class GroupsService {
       currency: group.currency as 'USD' | 'EUR' | 'INR',
       createdBy: group.createdBy,
       createdAt: group.createdAt.toISOString(),
+      defaultSplitPreference: this.parseDefaultSplitPreference(group.defaultSplitType, group.defaultSplitConfig),
     }));
   }
 
@@ -100,6 +103,7 @@ export class GroupsService {
       currency: group.currency as 'USD' | 'EUR' | 'INR',
       createdBy: group.createdBy,
       createdAt: group.createdAt.toISOString(),
+      defaultSplitPreference: this.parseDefaultSplitPreference(group.defaultSplitType, group.defaultSplitConfig),
       members: group.members.map((member) => ({
         id: member.id,
         userId: member.userId,
@@ -209,13 +213,79 @@ export class GroupsService {
     };
   }
 
+  async updateDefaultSplit(groupId: string, actorUserId: string, dto: UpdateGroupDefaultSplitDto): Promise<GroupDto> {
+    await this.assertMembership(groupId, actorUserId);
+
+    let normalizedPreference: GroupDefaultSplitDto | null = null;
+    if (dto.defaultSplitPreference) {
+      const members = await this.prisma.groupMember.findMany({
+        where: { groupId },
+        select: { userId: true },
+      });
+      const memberIds = new Set(members.map((member) => member.userId));
+      const participantUserIds = Array.from(new Set(dto.defaultSplitPreference.participantUserIds));
+
+      if (participantUserIds.length === 0) {
+        throw new ForbiddenException('Default split must include at least one participant');
+      }
+
+      const invalidParticipant = participantUserIds.find((userId) => !memberIds.has(userId));
+      if (invalidParticipant) {
+        throw new ForbiddenException('Default split participants must belong to the group');
+      }
+
+      normalizedPreference = {
+        splitType: dto.defaultSplitPreference.splitType,
+        participantUserIds,
+        exactAmountsCentsByUser: dto.defaultSplitPreference.exactAmountsCentsByUser,
+        percentagesByUser: dto.defaultSplitPreference.percentagesByUser,
+      };
+    }
+
+    await this.prisma.group.update({
+      where: { id: groupId },
+      data: {
+        defaultSplitType: normalizedPreference?.splitType ?? null,
+        defaultSplitConfig: normalizedPreference
+          ? JSON.stringify({
+              participantUserIds: normalizedPreference.participantUserIds,
+              exactAmountsCentsByUser: normalizedPreference.exactAmountsCentsByUser ?? {},
+              percentagesByUser: normalizedPreference.percentagesByUser ?? {},
+            })
+          : null,
+      },
+    });
+
+    const group = await this.prisma.group.findUniqueOrThrow({
+      where: { id: groupId },
+      include: { members: true },
+    });
+
+    await this.redis.invalidateGroupCache(groupId);
+
+    return {
+      id: group.id,
+      name: group.name,
+      currency: group.currency as 'USD' | 'EUR' | 'INR',
+      createdBy: group.createdBy,
+      createdAt: group.createdAt.toISOString(),
+      defaultSplitPreference: this.parseDefaultSplitPreference(group.defaultSplitType, group.defaultSplitConfig),
+      members: group.members.map((member) => ({
+        id: member.id,
+        userId: member.userId,
+        groupId: member.groupId,
+        role: member.role,
+        joinedAt: member.joinedAt.toISOString(),
+      })),
+    };
+  }
+
   async invite(groupId: string, actorUserId: string, dto: InviteMemberDto): Promise<{ success: true }> {
     await this.assertMembership(groupId, actorUserId);
     const email = dto.email.toLowerCase();
 
     const user = await this.prisma.user.findUnique({ where: { email } });
     if (!user) {
-      // Create or update pending invitation
       await this.prisma.groupInvite.upsert({
         where: {
           groupId_email: {
@@ -229,7 +299,7 @@ export class GroupsService {
           invitedBy: actorUserId,
           role: 'MEMBER',
         },
-        update: {}, // Already invited, no-op
+        update: {},
       });
       return { success: true };
     }
@@ -298,7 +368,6 @@ export class GroupsService {
 
     await this.prisma.$transaction(async (tx) => {
       for (const invite of invites) {
-        // Create membership
         await tx.groupMember.create({
           data: {
             groupId: invite.groupId,
@@ -307,7 +376,6 @@ export class GroupsService {
           },
         });
 
-        // Add activity
         await tx.activity.create({
           data: {
             groupId: invite.groupId,
@@ -318,17 +386,46 @@ export class GroupsService {
           },
         });
 
-        // Delete invite
         await tx.groupInvite.delete({
           where: { id: invite.id },
         });
 
-        // Invalidate cache for each group
         await this.redis.invalidateGroupCache(invite.groupId);
       }
     });
   }
 
+  private parseDefaultSplitPreference(splitType: string | null, splitConfig: string | null): GroupDefaultSplitDto | null {
+    if (!splitType || !splitConfig) {
+      return null;
+    }
+
+    try {
+      const config = JSON.parse(splitConfig) as {
+        participantUserIds?: unknown;
+        exactAmountsCentsByUser?: unknown;
+        percentagesByUser?: unknown;
+      };
+
+      return {
+        splitType: splitType as GroupDefaultSplitDto['splitType'],
+        participantUserIds: Array.isArray(config.participantUserIds)
+          ? config.participantUserIds.filter((value): value is string => typeof value === 'string')
+          : [],
+        exactAmountsCentsByUser:
+          config.exactAmountsCentsByUser && typeof config.exactAmountsCentsByUser === 'object' && !Array.isArray(config.exactAmountsCentsByUser)
+            ? (config.exactAmountsCentsByUser as Record<string, string>)
+            : undefined,
+        percentagesByUser:
+          config.percentagesByUser && typeof config.percentagesByUser === 'object' && !Array.isArray(config.percentagesByUser)
+            ? (config.percentagesByUser as Record<string, string>)
+            : undefined,
+      };
+    } catch {
+      return null;
+    }
+  }
+
   private async assertMembership(groupId: string, userId: string): Promise<void> {
     const membership = await this.prisma.groupMember.findUnique({
       where: {