feat: transaction activity audit and account activity audit

internal/service/account_activity.go

@@ -0,0 +1,77 @@
+package service
+
+import (
+	"fmt"
+	"sort"
+
+	"git.juancwu.dev/juancwu/budgit/internal/model"
+)
+
+type AccountActivityService struct {
+	spaceAudit *SpaceAuditLogService
+	txAudit    *TransactionAuditLogService
+}
+
+func NewAccountActivityService(spaceAudit *SpaceAuditLogService, txAudit *TransactionAuditLogService) *AccountActivityService {
+	return &AccountActivityService{
+		spaceAudit: spaceAudit,
+		txAudit:    txAudit,
+	}
+}
+
+// List returns a merged feed of account-scoped events (account.created/renamed/deleted)
+// and transaction events (created/edited/deleted) for transactions in this account.
+//
+// Rather than a SQL UNION across two heterogeneous tables, we fetch up to (offset+limit)
+// from each side and merge in Go. Audit volume per account is low, so the simplicity
+// outweighs the slight overfetch.
+func (s *AccountActivityService) List(accountID string, limit, offset int) ([]model.AccountActivityRow, error) {
+	if limit <= 0 {
+		limit = 25
+	}
+	if offset < 0 {
+		offset = 0
+	}
+	fetchN := offset + limit
+
+	spaceLogs, err := s.spaceAudit.repo.ListAccountEvents(accountID, fetchN, 0)
+	if err != nil {
+		return nil, fmt.Errorf("failed to list account events: %w", err)
+	}
+	txLogs, err := s.txAudit.repo.ListByAccount(accountID, fetchN, 0)
+	if err != nil {
+		return nil, fmt.Errorf("failed to list transaction events: %w", err)
+	}
+
+	rows := make([]model.AccountActivityRow, 0, len(spaceLogs)+len(txLogs))
+	for _, l := range spaceLogs {
+		rows = append(rows, model.AccountActivityRow{SpaceLog: l})
+	}
+	for _, l := range txLogs {
+		rows = append(rows, model.AccountActivityRow{TxLog: l})
+	}
+	sort.Slice(rows, func(i, j int) bool {
+		return rows[i].Timestamp().After(rows[j].Timestamp())
+	})
+
+	if offset >= len(rows) {
+		return nil, nil
+	}
+	end := offset + limit
+	if end > len(rows) {
+		end = len(rows)
+	}
+	return rows[offset:end], nil
+}
+
+func (s *AccountActivityService) Count(accountID string) (int, error) {
+	spaceCount, err := s.spaceAudit.repo.CountAccountEvents(accountID)
+	if err != nil {
+		return 0, fmt.Errorf("failed to count account events: %w", err)
+	}
+	txCount, err := s.txAudit.repo.CountByAccount(accountID)
+	if err != nil {
+		return 0, fmt.Errorf("failed to count transaction events: %w", err)
+	}
+	return spaceCount + txCount, nil
+}