duempelkas/.github/prompts/02-domain-model.prompt.md

description, agent

description	agent
Implement the EF Core entity classes and enums for Account, AccountYear, Entry, TransferLink, and EntryType	agent

Step 2: Domain Model

Implement the domain entities under src/Duempelkas.Domain.

Entities

Account (Entities/Account.cs)

• int Id (PK)
• string Name (required, max 200)
• DateTime CreatedUtc
• ICollection<AccountYear> AccountYears (navigation)

AccountYear (Entities/AccountYear.cs)

• int Id (PK)
• int AccountId (FK → Account)
• int Year (e.g. 2026)
• decimal OpeningBalance — explicit carryover from the previous year, user-entered
• DateTime CreatedUtc
• Account Account (navigation)
• ICollection<Entry> Entries (navigation)

Constraint: unique on (AccountId, Year).

Entry (Entities/Entry.cs)

• int Id (PK)
• int AccountYearId (FK → AccountYear)
• EntryType Type — Income or Expense
• DateTime Date
• string Title (required, max 500)
• decimal Amount — always positive; sign determined by Type
• int? TransferLinkId (FK → TransferLink, nullable)
• DateTime CreatedUtc
• AccountYear AccountYear (navigation)
• TransferLink? TransferLink (navigation)

TransferLink (Entities/TransferLink.cs)

• int Id (PK)
• int SourceEntryId (FK → Entry, unique)
• int TargetEntryId (FK → Entry, unique)
• string? Note
• DateTime CreatedUtc
• Entry SourceEntry (navigation)
• Entry TargetEntry (navigation)

Invariants enforced at service level:

• SourceEntry.Type must be Expense
• TargetEntry.Type must be Income
• Both share the same Amount and Date

EntryType (Enums/EntryType.cs)

public enum EntryType { Income = 0, Expense = 1 }

Conventions

• Use decimal for all monetary amounts.
• Store amounts as positive; behaviour (add/subtract) comes from EntryType.
• File-scoped namespaces, nullable enabled.