feat(finance): support weighted rent split

apps/bot/src/anonymous-feedback.test.ts

@@ -159,6 +159,7 @@ function createHouseholdConfigurationRepository(): HouseholdConfigurationReposit
       displayName: input.displayName,
       preferredLocale: input.preferredLocale ?? null,
       householdDefaultLocale: 'ru',
+      rentShareWeight: 1,
       isAdmin: input.isAdmin === true
     }),
     getHouseholdMember: async () => null,
@@ -171,6 +172,7 @@ function createHouseholdConfigurationRepository(): HouseholdConfigurationReposit
         displayName: 'Stan',
         preferredLocale: null,
         householdDefaultLocale: 'ru',
+        rentShareWeight: 1,
         isAdmin: false
       }
     ],
@@ -191,6 +193,7 @@ function createHouseholdConfigurationRepository(): HouseholdConfigurationReposit
       displayName: 'Stan',
       preferredLocale: locale,
       householdDefaultLocale: 'ru',
+      rentShareWeight: 1,
       isAdmin: false
     }),
     getHouseholdBillingSettings: async (householdId) => ({
@@ -222,7 +225,8 @@ function createHouseholdConfigurationRepository(): HouseholdConfigurationReposit
       sortOrder: input.sortOrder,
       isActive: input.isActive
     }),
-    promoteHouseholdAdmin: async () => null
+    promoteHouseholdAdmin: async () => null,
+    updateHouseholdMemberRentShareWeight: async () => null
   }
 }
 

apps/bot/src/miniapp-auth.test.ts

@@ -28,6 +28,7 @@ function onboardingRepository(): HouseholdConfigurationRepository {
       displayName: string
       preferredLocale: 'en' | 'ru' | null
       householdDefaultLocale: 'en' | 'ru'
+      rentShareWeight: number
       isAdmin: boolean
     }
   >()
@@ -97,6 +98,7 @@ function onboardingRepository(): HouseholdConfigurationRepository {
         displayName: input.displayName,
         preferredLocale: input.preferredLocale ?? null,
         householdDefaultLocale: household.defaultLocale,
+        rentShareWeight: 1,
         isAdmin: input.isAdmin === true
       }
       members.set(input.telegramUserId, member)
@@ -122,6 +124,7 @@ function onboardingRepository(): HouseholdConfigurationRepository {
         displayName: pending.displayName,
         preferredLocale: null,
         householdDefaultLocale: household.defaultLocale,
+        rentShareWeight: 1,
         isAdmin: input.isAdmin === true
       }
       members.set(pending.telegramUserId, member)
@@ -141,6 +144,15 @@ function onboardingRepository(): HouseholdConfigurationRepository {
           }
         : null
     },
+    updateHouseholdMemberRentShareWeight: async (_householdId, memberId, rentShareWeight) => {
+      const member = [...members.values()].find((entry) => entry.id === memberId)
+      return member
+        ? {
+            ...member,
+            rentShareWeight
+          }
+        : null
+    },
     getHouseholdBillingSettings: async (householdId) => ({
       householdId,
       rentAmountMinor: null,

apps/bot/src/miniapp-billing.test.ts

@@ -70,6 +70,7 @@ function onboardingRepository(): HouseholdConfigurationRepository {
       displayName: input.displayName,
       preferredLocale: input.preferredLocale ?? null,
       householdDefaultLocale: household.defaultLocale,
+      rentShareWeight: 1,
       isAdmin: input.isAdmin === true
     }),
     getHouseholdMember: async () => null,
@@ -111,6 +112,7 @@ function onboardingRepository(): HouseholdConfigurationRepository {
         displayName: 'Stan',
         preferredLocale: null,
         householdDefaultLocale: 'ru',
+        rentShareWeight: 1,
         isAdmin: true
       }
     ],
@@ -121,7 +123,8 @@ function onboardingRepository(): HouseholdConfigurationRepository {
       defaultLocale: locale
     }),
     updateMemberPreferredLocale: async () => null,
-    promoteHouseholdAdmin: async () => null
+    promoteHouseholdAdmin: async () => null,
+    updateHouseholdMemberRentShareWeight: async () => null
   }
 }
 

apps/bot/src/miniapp-dashboard.test.ts

@@ -24,6 +24,7 @@ function repository(
         id: 'member-1',
         telegramUserId: '123456',
         displayName: 'Stan',
+        rentShareWeight: 1,
         isAdmin: true
       }
     ],
@@ -124,6 +125,7 @@ function onboardingRepository(): HouseholdConfigurationRepository {
       displayName: input.displayName,
       preferredLocale: input.preferredLocale ?? null,
       householdDefaultLocale: household.defaultLocale,
+      rentShareWeight: 1,
       isAdmin: input.isAdmin === true
     }),
     getHouseholdMember: async () => null,
@@ -165,7 +167,8 @@ function onboardingRepository(): HouseholdConfigurationRepository {
       sortOrder: input.sortOrder,
       isActive: input.isActive
     }),
-    promoteHouseholdAdmin: async () => null
+    promoteHouseholdAdmin: async () => null,
+    updateHouseholdMemberRentShareWeight: async () => null
   }
 }
 
@@ -177,6 +180,7 @@ describe('createMiniAppDashboardHandler', () => {
         id: 'member-1',
         telegramUserId: '123456',
         displayName: 'Stan',
+        rentShareWeight: 1,
         isAdmin: true
       })
     )
@@ -189,6 +193,7 @@ describe('createMiniAppDashboardHandler', () => {
         displayName: 'Stan',
         preferredLocale: null,
         householdDefaultLocale: 'ru',
+        rentShareWeight: 1,
         isAdmin: true
       }
     ]
@@ -255,6 +260,7 @@ describe('createMiniAppDashboardHandler', () => {
         id: 'member-1',
         telegramUserId: '123456',
         displayName: 'Stan',
+        rentShareWeight: 1,
         isAdmin: true
       })
     )
@@ -267,6 +273,7 @@ describe('createMiniAppDashboardHandler', () => {
         displayName: 'Stan',
         preferredLocale: null,
         householdDefaultLocale: 'ru',
+        rentShareWeight: 1,
         isAdmin: true
       }
     ]

apps/bot/src/miniapp-locale.test.ts

@@ -33,6 +33,7 @@ function repository(): HouseholdConfigurationRepository {
         displayName: 'Stan',
         preferredLocale: null,
         householdDefaultLocale: household.defaultLocale,
+        rentShareWeight: 1,
         isAdmin: true
       }
     ],
@@ -45,6 +46,7 @@ function repository(): HouseholdConfigurationRepository {
         displayName: 'Mia',
         preferredLocale: null,
         householdDefaultLocale: household.defaultLocale,
+        rentShareWeight: 1,
         isAdmin: false
       }
     ]
@@ -92,6 +94,7 @@ function repository(): HouseholdConfigurationRepository {
         displayName: input.displayName,
         preferredLocale: input.preferredLocale ?? null,
         householdDefaultLocale: household.defaultLocale,
+        rentShareWeight: 1,
         isAdmin: input.isAdmin === true
       },
     getHouseholdMember: async (_householdId, telegramUserId) => members.get(telegramUserId) ?? null,
@@ -154,7 +157,8 @@ function repository(): HouseholdConfigurationRepository {
       sortOrder: input.sortOrder,
       isActive: input.isActive
     }),
-    promoteHouseholdAdmin: async () => null
+    promoteHouseholdAdmin: async () => null,
+    updateHouseholdMemberRentShareWeight: async () => null
   }
 }
 

docs/specs/HOUSEBOT-077-custom-rent-split-weights.md

@@ -0,0 +1,48 @@
+# HOUSEBOT-077 Custom Rent Split Weights
+
+## Summary
+
+Support unequal room rents by storing a deterministic rent-share weight per active household member and using those weights in monthly settlement calculations.
+
+## Goals
+
+- Preserve equal split as the default when all member weights are `1`.
+- Allow household admins to edit per-member rent weights from the mini app.
+- Keep settlement math deterministic and money-safe.
+- Reflect weighted rent shares consistently in statements and dashboard views.
+
+## Non-goals
+
+- Per-cycle rent weights.
+- Free-form percentage editing.
+- Automatic square-meter or room-type calculations.
+
+## Scope
+
+- In: member-level `rentShareWeight`, settlement-engine support, admin API/UI, tests.
+- Out: historical backfill UI, move-in/move-out proration logic, rent history analytics.
+
+## Data Model Changes
+
+- Add `members.rent_share_weight integer not null default 1`.
+- Existing members migrate to `1`.
+
+## Domain Rules
+
+- Rent weights must be positive integers.
+- Active members participate in rent splitting according to their weight.
+- Utility splitting remains independent from rent splitting.
+- The same input must always produce the same minor-unit allocation.
+
+## Interfaces
+
+- Household admin mini app payload includes member `rentShareWeight`.
+- Admin write endpoint updates one member rent weight at a time.
+
+## Acceptance Criteria
+
+- [ ] Settlement engine uses weighted rent shares.
+- [ ] Equal split still holds when all weights are `1`.
+- [ ] Admins can edit member rent weights in the mini app.
+- [ ] Dashboard and statements reflect the new rent shares.
+- [ ] Validation rejects zero or negative weights.

packages/adapters-db/src/finance-repository.ts

@@ -38,6 +38,7 @@ export function createDbFinanceRepository(
           id: schema.members.id,
           telegramUserId: schema.members.telegramUserId,
           displayName: schema.members.displayName,
+          rentShareWeight: schema.members.rentShareWeight,
           isAdmin: schema.members.isAdmin
         })
         .from(schema.members)
@@ -66,6 +67,7 @@ export function createDbFinanceRepository(
           id: schema.members.id,
           telegramUserId: schema.members.telegramUserId,
           displayName: schema.members.displayName,
+          rentShareWeight: schema.members.rentShareWeight,
           isAdmin: schema.members.isAdmin
         })
         .from(schema.members)

packages/adapters-db/src/household-config-repository.ts

@@ -115,6 +115,7 @@ function toHouseholdMemberRecord(row: {
   displayName: string
   preferredLocale: string | null
   defaultLocale: string
+  rentShareWeight: number
   isAdmin: number
 }): HouseholdMemberRecord {
   const householdDefaultLocale = normalizeSupportedLocale(row.defaultLocale)
@@ -129,6 +130,7 @@ function toHouseholdMemberRecord(row: {
     displayName: row.displayName,
     preferredLocale: normalizeSupportedLocale(row.preferredLocale),
     householdDefaultLocale,
+    rentShareWeight: row.rentShareWeight,
     isAdmin: row.isAdmin === 1
   }
 }
@@ -766,6 +768,7 @@ export function createDbHouseholdConfigurationRepository(databaseUrl: string): {
           telegramUserId: input.telegramUserId,
           displayName: input.displayName,
           preferredLocale: input.preferredLocale ?? null,
+          rentShareWeight: input.rentShareWeight ?? 1,
           isAdmin: input.isAdmin ? 1 : 0
         })
         .onConflictDoUpdate({
@@ -773,6 +776,7 @@ export function createDbHouseholdConfigurationRepository(databaseUrl: string): {
           set: {
             displayName: input.displayName,
             preferredLocale: input.preferredLocale ?? schema.members.preferredLocale,
+            rentShareWeight: input.rentShareWeight ?? schema.members.rentShareWeight,
             ...(input.isAdmin
               ? {
                   isAdmin: 1
@@ -786,6 +790,7 @@ export function createDbHouseholdConfigurationRepository(databaseUrl: string): {
           telegramUserId: schema.members.telegramUserId,
           displayName: schema.members.displayName,
           preferredLocale: schema.members.preferredLocale,
+          rentShareWeight: schema.members.rentShareWeight,
           isAdmin: schema.members.isAdmin
         })
 
@@ -813,6 +818,7 @@ export function createDbHouseholdConfigurationRepository(databaseUrl: string): {
           telegramUserId: schema.members.telegramUserId,
           displayName: schema.members.displayName,
           preferredLocale: schema.members.preferredLocale,
+          rentShareWeight: schema.members.rentShareWeight,
           defaultLocale: schema.households.defaultLocale,
           isAdmin: schema.members.isAdmin
         })
@@ -838,6 +844,7 @@ export function createDbHouseholdConfigurationRepository(databaseUrl: string): {
           telegramUserId: schema.members.telegramUserId,
           displayName: schema.members.displayName,
           preferredLocale: schema.members.preferredLocale,
+          rentShareWeight: schema.members.rentShareWeight,
           defaultLocale: schema.households.defaultLocale,
           isAdmin: schema.members.isAdmin
         })
@@ -1012,6 +1019,7 @@ export function createDbHouseholdConfigurationRepository(databaseUrl: string): {
           telegramUserId: schema.members.telegramUserId,
           displayName: schema.members.displayName,
           preferredLocale: schema.members.preferredLocale,
+          rentShareWeight: schema.members.rentShareWeight,
           defaultLocale: schema.households.defaultLocale,
           isAdmin: schema.members.isAdmin
         })
@@ -1082,6 +1090,7 @@ export function createDbHouseholdConfigurationRepository(databaseUrl: string): {
             telegramUserId: pending.telegramUserId,
             displayName: pending.displayName,
             preferredLocale: normalizeSupportedLocale(pending.languageCode),
+            rentShareWeight: 1,
             isAdmin: input.isAdmin ? 1 : 0
           })
           .onConflictDoUpdate({
@@ -1103,6 +1112,7 @@ export function createDbHouseholdConfigurationRepository(databaseUrl: string): {
             telegramUserId: schema.members.telegramUserId,
             displayName: schema.members.displayName,
             preferredLocale: schema.members.preferredLocale,
+            rentShareWeight: schema.members.rentShareWeight,
             isAdmin: schema.members.isAdmin
           })
 
@@ -1174,6 +1184,7 @@ export function createDbHouseholdConfigurationRepository(databaseUrl: string): {
           telegramUserId: schema.members.telegramUserId,
           displayName: schema.members.displayName,
           preferredLocale: schema.members.preferredLocale,
+          rentShareWeight: schema.members.rentShareWeight,
           isAdmin: schema.members.isAdmin
         })
 
@@ -1206,6 +1217,7 @@ export function createDbHouseholdConfigurationRepository(databaseUrl: string): {
           telegramUserId: schema.members.telegramUserId,
           displayName: schema.members.displayName,
           preferredLocale: schema.members.preferredLocale,
+          rentShareWeight: schema.members.rentShareWeight,
           isAdmin: schema.members.isAdmin
         })
 
@@ -1219,6 +1231,39 @@ export function createDbHouseholdConfigurationRepository(databaseUrl: string): {
         throw new Error('Failed to resolve household chat after admin promotion')
       }
 
+      return toHouseholdMemberRecord({
+        ...row,
+        defaultLocale: household.defaultLocale
+      })
+    },
+
+    async updateHouseholdMemberRentShareWeight(householdId, memberId, rentShareWeight) {
+      const rows = await db
+        .update(schema.members)
+        .set({
+          rentShareWeight
+        })
+        .where(and(eq(schema.members.householdId, householdId), eq(schema.members.id, memberId)))
+        .returning({
+          id: schema.members.id,
+          householdId: schema.members.householdId,
+          telegramUserId: schema.members.telegramUserId,
+          displayName: schema.members.displayName,
+          preferredLocale: schema.members.preferredLocale,
+          rentShareWeight: schema.members.rentShareWeight,
+          isAdmin: schema.members.isAdmin
+        })
+
+      const row = rows[0]
+      if (!row) {
+        return null
+      }
+
+      const household = await this.getHouseholdChatByHouseholdId(householdId)
+      if (!household) {
+        throw new Error('Failed to resolve household chat after rent weight update')
+      }
+
       return toHouseholdMemberRecord({
         ...row,
         defaultLocale: household.defaultLocale

packages/application/src/finance-command-service.test.ts

@@ -216,12 +216,14 @@ describe('createFinanceCommandService', () => {
         id: 'alice',
         telegramUserId: '100',
         displayName: 'Alice',
+        rentShareWeight: 1,
         isAdmin: true
       },
       {
         id: 'bob',
         telegramUserId: '200',
         displayName: 'Bob',
+        rentShareWeight: 1,
         isAdmin: false
       }
     ]

packages/application/src/finance-command-service.ts

@@ -130,7 +130,8 @@ async function buildFinanceDashboard(
     utilitySplitMode: 'equal',
     members: members.map((member) => ({
       memberId: MemberId.from(member.id),
-      active: true
+      active: true,
+      rentWeight: member.rentShareWeight
     })),
     purchases: purchases.map((purchase) => ({
       purchaseId: PurchaseEntryId.from(purchase.id),

packages/application/src/household-admin-service.test.ts

@@ -30,6 +30,7 @@ function createRepositoryStub() {
     displayName: 'Stan',
     preferredLocale: null,
     householdDefaultLocale: household.defaultLocale,
+    rentShareWeight: 1,
     isAdmin: true
   })
   pendingMembers.set('2', {
@@ -94,6 +95,7 @@ function createRepositoryStub() {
         displayName: input.displayName,
         preferredLocale: input.preferredLocale ?? null,
         householdDefaultLocale: household.defaultLocale,
+        rentShareWeight: 1,
         isAdmin: input.isAdmin === true
       }
       members.set(input.telegramUserId, record)
@@ -120,6 +122,7 @@ function createRepositoryStub() {
         displayName: pending.displayName,
         preferredLocale: null,
         householdDefaultLocale: household.defaultLocale,
+        rentShareWeight: 1,
         isAdmin: input.isAdmin === true
       }
       members.set(member.telegramUserId, member)
@@ -167,7 +170,8 @@ function createRepositoryStub() {
       sortOrder: input.sortOrder,
       isActive: input.isActive
     }),
-    promoteHouseholdAdmin: async () => null
+    promoteHouseholdAdmin: async () => null,
+    updateHouseholdMemberRentShareWeight: async () => null
   }
 
   return {
@@ -238,6 +242,7 @@ describe('createHouseholdAdminService', () => {
         displayName: 'Alice',
         preferredLocale: null,
         householdDefaultLocale: 'ru',
+        rentShareWeight: 1,
         isAdmin: false
       }
     })

packages/application/src/household-onboarding-service.test.ts

@@ -100,6 +100,7 @@ function createRepositoryStub() {
         displayName: input.displayName,
         preferredLocale: input.preferredLocale ?? null,
         householdDefaultLocale: household.defaultLocale,
+        rentShareWeight: 1,
         isAdmin: input.isAdmin === true
       }
       members.set(input.telegramUserId, member)
@@ -133,6 +134,7 @@ function createRepositoryStub() {
         displayName: pending.displayName,
         preferredLocale: null,
         householdDefaultLocale: household.defaultLocale,
+        rentShareWeight: 1,
         isAdmin: input.isAdmin === true
       }
     },
@@ -190,6 +192,9 @@ function createRepositoryStub() {
     },
     async promoteHouseholdAdmin() {
       return null
+    },
+    async updateHouseholdMemberRentShareWeight() {
+      return null
     }
   }
 
@@ -319,6 +324,7 @@ describe('createHouseholdOnboardingService', () => {
         displayName: 'Stan',
         preferredLocale: null,
         householdDefaultLocale: 'ru',
+        rentShareWeight: 1,
         isAdmin: true
       }
     })
@@ -333,13 +339,14 @@ describe('createHouseholdOnboardingService', () => {
       displayName: 'Stan',
       preferredLocale: null,
       householdDefaultLocale: 'ru',
+      rentShareWeight: 1,
       isAdmin: true
     }
     const service = createHouseholdOnboardingService({ repository })
     const duplicateRepository = repository as HouseholdConfigurationRepository & {
       listHouseholdMembersByTelegramUserId: (
         telegramUserId: string
-      ) => Promise<readonly HouseholdMemberRecord[]>
+      ) => Promise<readonly (HouseholdMemberRecord & { rentShareWeight: number })[]>
     }
     duplicateRepository.listHouseholdMembersByTelegramUserId = async () => [
       member,
@@ -350,6 +357,7 @@ describe('createHouseholdOnboardingService', () => {
         displayName: 'Stan elsewhere',
         preferredLocale: null,
         householdDefaultLocale: 'ru',
+        rentShareWeight: 1,
         isAdmin: false
       }
     ]

packages/application/src/household-onboarding-service.ts

@@ -20,6 +20,7 @@ export type HouseholdMiniAppAccess =
         isAdmin: boolean
         preferredLocale: SupportedLocale | null
         householdDefaultLocale: SupportedLocale
+        rentShareWeight: number
       }
     }
   | {
@@ -70,6 +71,7 @@ export interface HouseholdOnboardingService {
           isAdmin: boolean
           preferredLocale: SupportedLocale | null
           householdDefaultLocale: SupportedLocale
+          rentShareWeight: number
         }
       }
     | {
@@ -85,6 +87,7 @@ function toMember(member: HouseholdMemberRecord): {
   isAdmin: boolean
   preferredLocale: SupportedLocale | null
   householdDefaultLocale: SupportedLocale
+  rentShareWeight: number
 } {
   return {
     id: member.id,
@@ -92,7 +95,8 @@ function toMember(member: HouseholdMemberRecord): {
     displayName: member.displayName,
     isAdmin: member.isAdmin,
     preferredLocale: member.preferredLocale,
-    householdDefaultLocale: member.householdDefaultLocale
+    householdDefaultLocale: member.householdDefaultLocale,
+    rentShareWeight: member.rentShareWeight
   }
 }
 

packages/application/src/household-setup-service.test.ts

@@ -175,6 +175,7 @@ function createRepositoryStub() {
         householdDefaultLocale:
           [...households.values()].find((household) => household.householdId === input.householdId)
             ?.defaultLocale ?? 'ru',
+        rentShareWeight: input.rentShareWeight ?? existing?.rentShareWeight ?? 1,
         isAdmin: input.isAdmin === true || existing?.isAdmin === true
       }
       members.set(key, next)
@@ -216,6 +217,7 @@ function createRepositoryStub() {
           [...households.values()].find(
             (household) => household.householdId === pending.householdId
           )?.defaultLocale ?? 'ru',
+        rentShareWeight: 1,
         isAdmin: input.isAdmin === true
       }
       members.set(key, member)
@@ -296,6 +298,22 @@ function createRepositoryStub() {
       }
       members.set(`${householdId}:${member.telegramUserId}`, next)
       return next
+    },
+
+    async updateHouseholdMemberRentShareWeight(householdId, memberId, rentShareWeight) {
+      const member = [...members.values()].find(
+        (entry) => entry.householdId === householdId && entry.id === memberId
+      )
+      if (!member) {
+        return null
+      }
+
+      const next = {
+        ...member,
+        rentShareWeight
+      }
+      members.set(`${householdId}:${member.telegramUserId}`, next)
+      return next
     }
   }
 
@@ -332,6 +350,7 @@ describe('createHouseholdSetupService', () => {
       displayName: 'Stan',
       preferredLocale: null,
       householdDefaultLocale: 'ru',
+      rentShareWeight: 1,
       isAdmin: true
     })
   })
@@ -369,6 +388,7 @@ describe('createHouseholdSetupService', () => {
       displayName: 'Mia',
       preferredLocale: null,
       householdDefaultLocale: 'ru',
+      rentShareWeight: 1,
       isAdmin: true
     })
   })

packages/application/src/locale-preference-service.test.ts

@@ -21,6 +21,7 @@ function createRepository(): HouseholdConfigurationRepository {
     displayName: 'Stan',
     preferredLocale: null,
     householdDefaultLocale: 'ru',
+    rentShareWeight: 1,
     isAdmin: true
   }
 
@@ -104,7 +105,8 @@ function createRepository(): HouseholdConfigurationRepository {
       sortOrder: input.sortOrder,
       isActive: input.isActive
     }),
-    promoteHouseholdAdmin: async () => null
+    promoteHouseholdAdmin: async () => null,
+    updateHouseholdMemberRentShareWeight: async () => null
   }
 }
 

packages/application/src/settlement-engine.test.ts

@@ -83,6 +83,25 @@ describe('calculateMonthlySettlement', () => {
     expect(result.totalDue.amountMinor).toBe(82000n)
   })
 
+  test('supports weighted rent split by member weights', () => {
+    const input = {
+      ...fixtureBase(),
+      utilitySplitMode: 'equal' as const,
+      members: [
+        { memberId: MemberId.from('a'), active: true, rentWeight: 3 },
+        { memberId: MemberId.from('b'), active: true, rentWeight: 2 },
+        { memberId: MemberId.from('c'), active: true, rentWeight: 1 }
+      ],
+      purchases: []
+    }
+
+    const result = calculateMonthlySettlement(input)
+
+    expect(result.lines.map((line) => line.rentShare.amountMinor)).toEqual([35000n, 23333n, 11667n])
+    expect(result.lines.map((line) => line.utilityShare.amountMinor)).toEqual([4000n, 4000n, 4000n])
+    expect(result.totalDue.amountMinor).toBe(82000n)
+  })
+
   test('5-member scenario with two purchases remains deterministic', () => {
     const input = {
       ...fixtureBase(),
@@ -150,4 +169,18 @@ describe('calculateMonthlySettlement', () => {
 
     expect(() => calculateMonthlySettlement(input)).toThrow(DomainError)
   })
+
+  test('throws if rent split is selected with invalid rent weights', () => {
+    const input = {
+      ...fixtureBase(),
+      utilitySplitMode: 'equal' as const,
+      members: [
+        { memberId: MemberId.from('a'), active: true, rentWeight: 1 },
+        { memberId: MemberId.from('b'), active: true, rentWeight: 0 }
+      ],
+      purchases: []
+    }
+
+    expect(() => calculateMonthlySettlement(input)).toThrow(DomainError)
+  })
 })

packages/application/src/settlement-engine.ts

@@ -82,6 +82,31 @@ function validateWeightedUtilityDays(members: readonly SettlementMemberInput[]):
   return weights
 }
 
+function validateRentWeights(members: readonly SettlementMemberInput[]): readonly bigint[] {
+  const weights = members.map((member) => {
+    const raw = member.rentWeight ?? 1
+
+    if (!Number.isInteger(raw) || raw <= 0) {
+      throw new DomainError(
+        DOMAIN_ERROR_CODE.INVALID_SETTLEMENT_INPUT,
+        `rentWeight must be a positive integer for member ${member.memberId.toString()}`
+      )
+    }
+
+    return BigInt(raw)
+  })
+
+  const total = weights.reduce((sum, current) => sum + current, 0n)
+  if (total <= 0n) {
+    throw new DomainError(
+      DOMAIN_ERROR_CODE.INVALID_SETTLEMENT_INPUT,
+      'Total rent weights must be positive'
+    )
+  }
+
+  return weights
+}
+
 function validateCurrencyConsistency(input: SettlementInput): void {
   const currency = input.rent.currency
 
@@ -114,7 +139,7 @@ export function calculateMonthlySettlement(input: SettlementInput): SettlementRe
     activeMembers.map((member) => [member.memberId.toString(), createMemberState(member, currency)])
   )
 
-  const rentShares = input.rent.splitEvenly(activeMembers.length)
+  const rentShares = input.rent.splitByWeights(validateRentWeights(activeMembers))
   for (const [index, member] of activeMembers.entries()) {
     const state = membersById.get(member.memberId.toString())
     if (!state) {

packages/db/drizzle-checksums.json

@@ -10,6 +10,8 @@
     "0006_marvelous_nehzno.sql": "369a862f68dede5568116e29865aa3c8a7a0ff494487af1b202b62932ffe83f4",
     "0007_sudden_murmur.sql": "eedf265c46705c20be4ddb3e2bd7d9670108756915b911e580e19a00f8118104",
     "0008_lowly_spiral.sql": "4f016332d60f7ef1fef0311210a0fa1a0bfc1d9b6da1da4380a60c14d54a9681",
-    "0009_quiet_wallflower.sql": "c5bcb6a01b6f22a9e64866ac0d11468105aad8b2afb248296370f15b462e3087"
+    "0009_quiet_wallflower.sql": "c5bcb6a01b6f22a9e64866ac0d11468105aad8b2afb248296370f15b462e3087",
+    "0010_wild_molecule_man.sql": "46027a6ac770cdc2efd4c3eb5bb53f09d1b852c70fdc46a2434e5a7064587245",
+    "0011_previous_ezekiel_stane.sql": "d996e64d3854de22e36dedeaa94e46774399163d90263bbb05e0b9199af79b70"
   }
 }

packages/db/drizzle/0011_previous_ezekiel_stane.sql

@@ -0,0 +1 @@
+ALTER TABLE "members" ADD COLUMN "rent_share_weight" integer DEFAULT 1 NOT NULL;

packages/db/drizzle/meta/_journal.json

@@ -78,6 +78,13 @@
       "when": 1773092080214,
       "tag": "0010_wild_molecule_man",
       "breakpoints": true
+    },
+    {
+      "idx": 11,
+      "version": "7",
+      "when": 1773096404367,
+      "tag": "0011_previous_ezekiel_stane",
+      "breakpoints": true
     }
   ]
 }

packages/db/src/schema.ts

@@ -194,6 +194,7 @@ export const members = pgTable(
     telegramUserId: text('telegram_user_id').notNull(),
     displayName: text('display_name').notNull(),
     preferredLocale: text('preferred_locale'),
+    rentShareWeight: integer('rent_share_weight').default(1).notNull(),
     isAdmin: integer('is_admin').default(0).notNull(),
     joinedAt: timestamp('joined_at', { withTimezone: true }).defaultNow().notNull()
   },

packages/domain/src/settlement-primitives.ts

@@ -7,6 +7,7 @@ export type UtilitySplitMode = 'equal' | 'weighted_by_days'
 export interface SettlementMemberInput {
   memberId: MemberId
   active: boolean
+  rentWeight?: number
   utilityDays?: number
 }
 

packages/ports/src/finance.ts

@@ -4,6 +4,7 @@ export interface FinanceMemberRecord {
   id: string
   telegramUserId: string
   displayName: string
+  rentShareWeight: number
   isAdmin: boolean
 }
 

packages/ports/src/household-config.ts

@@ -45,6 +45,7 @@ export interface HouseholdMemberRecord {
   displayName: string
   preferredLocale: SupportedLocale | null
   householdDefaultLocale: SupportedLocale
+  rentShareWeight: number
   isAdmin: boolean
 }
 
@@ -128,6 +129,7 @@ export interface HouseholdConfigurationRepository {
     telegramUserId: string
     displayName: string
     preferredLocale?: SupportedLocale | null
+    rentShareWeight?: number
     isAdmin?: boolean
   }): Promise<HouseholdMemberRecord>
   getHouseholdMember(
@@ -178,4 +180,9 @@ export interface HouseholdConfigurationRepository {
     householdId: string,
     memberId: string
   ): Promise<HouseholdMemberRecord | null>
+  updateHouseholdMemberRentShareWeight(
+    householdId: string,
+    memberId: string,
+    rentShareWeight: number
+  ): Promise<HouseholdMemberRecord | null>
 }