using FinancialApi.Domain; using Wolverine.Attributes; using Wolverine.Persistence; namespace FinancialApi.Application; public record ApplyFeeCommand(int AccountId, decimal Amount); public record FeeAppliedEvent(int AccountId, decimal Amount); public static class ApplyFeeHandler { public static async Task<(Account, Account)> LoadAsync( ApplyFeeCommand cmd, IAccountQuery query) { var source = await query.FindByIdAsync(cmd.AccountId); var dest = await query.FindByIdAsync(99999); if (source == null || dest == null) { throw new InvalidOperationException($"Cannot process transfer. Account(s) not found."); } return (source, dest); } public static ( IStorageAction CustomerWrite, IStorageAction RevenueWrite, IStorageAction JournalWrite, FeeAppliedEvent Event ) Handle( ApplyFeeCommand cmd, Account source, Account dest ) { var updatedSource = source.ApplyPosting(cmd.Amount, EntryType.Debit); var updatedRevenue = dest.ApplyPosting(cmd.Amount, EntryType.Credit); var lines = new List { new(updatedSource.Id, cmd.Amount, EntryType.Debit), new(updatedRevenue.Id, cmd.Amount, EntryType.Credit) }; var journalEntry = BalancedJournal.Create(Guid.NewGuid(), $"Service Fee Applied: {cmd.Amount} to Account {cmd.AccountId}", DateTimeOffset.UtcNow, lines); var @event = new FeeAppliedEvent(cmd.AccountId, cmd.Amount); return ( Storage.Update(updatedSource), Storage.Update(updatedRevenue), Storage.Insert(journalEntry.Entry), @event ); } }