service backend

api/ledger/internal/service/ledger/helpers.go

@@ -0,0 +1,166 @@
+package ledger
+
+import (
+	"fmt"
+	"time"
+
+	ledgerv1 "github.com/tech/sendico/ledger/internal/generated/service/ledger/v1"
+	"github.com/tech/sendico/ledger/storage/model"
+	"github.com/tech/sendico/pkg/merrors"
+	moneyv1 "github.com/tech/sendico/pkg/proto/common/money/v1"
+	"github.com/shopspring/decimal"
+	"go.mongodb.org/mongo-driver/bson/primitive"
+	"google.golang.org/protobuf/types/known/timestamppb"
+)
+
+// parseObjectID converts a hex string to ObjectID
+func parseObjectID(hexID string) (primitive.ObjectID, error) {
+	if hexID == "" {
+		return primitive.NilObjectID, merrors.InvalidArgument("empty object ID")
+	}
+	oid, err := primitive.ObjectIDFromHex(hexID)
+	if err != nil {
+		return primitive.NilObjectID, merrors.InvalidArgument(fmt.Sprintf("invalid object ID: %v", err))
+	}
+	return oid, nil
+}
+
+// parseDecimal converts a string amount to decimal
+func parseDecimal(amount string) (decimal.Decimal, error) {
+	if amount == "" {
+		return decimal.Zero, merrors.InvalidArgument("empty amount")
+	}
+	dec, err := decimal.NewFromString(amount)
+	if err != nil {
+		return decimal.Zero, merrors.InvalidArgument(fmt.Sprintf("invalid decimal amount: %v", err))
+	}
+	return dec, nil
+}
+
+// validateMoney checks that a Money message is valid
+func validateMoney(m *moneyv1.Money, fieldName string) error {
+	if m == nil {
+		return merrors.InvalidArgument(fmt.Sprintf("%s: money is required", fieldName))
+	}
+	if m.Amount == "" {
+		return merrors.InvalidArgument(fmt.Sprintf("%s: amount is required", fieldName))
+	}
+	if m.Currency == "" {
+		return merrors.InvalidArgument(fmt.Sprintf("%s: currency is required", fieldName))
+	}
+	// Validate it's a valid decimal
+	if _, err := parseDecimal(m.Amount); err != nil {
+		return err
+	}
+	return nil
+}
+
+// validatePostingLines validates charge lines
+func validatePostingLines(lines []*ledgerv1.PostingLine) error {
+	for i, line := range lines {
+		if line == nil {
+			return merrors.InvalidArgument(fmt.Sprintf("charges[%d]: nil posting line", i))
+		}
+		if line.LedgerAccountRef == "" {
+			return merrors.InvalidArgument(fmt.Sprintf("charges[%d]: ledger_account_ref is required", i))
+		}
+		if line.Money == nil {
+			return merrors.InvalidArgument(fmt.Sprintf("charges[%d]: money is required", i))
+		}
+		if err := validateMoney(line.Money, fmt.Sprintf("charges[%d].money", i)); err != nil {
+			return err
+		}
+		// Charges should not be MAIN type
+		if line.LineType == ledgerv1.LineType_LINE_MAIN {
+			return merrors.InvalidArgument(fmt.Sprintf("charges[%d]: cannot have LINE_MAIN type", i))
+		}
+	}
+	return nil
+}
+
+// getEventTime extracts event time from proto or defaults to now
+func getEventTime(ts *timestamppb.Timestamp) time.Time {
+	if ts != nil && ts.IsValid() {
+		return ts.AsTime()
+	}
+	return time.Now().UTC()
+}
+
+// protoLineTypeToModel converts proto LineType to model LineType
+func protoLineTypeToModel(lt ledgerv1.LineType) model.LineType {
+	switch lt {
+	case ledgerv1.LineType_LINE_MAIN:
+		return model.LineTypeMain
+	case ledgerv1.LineType_LINE_FEE:
+		return model.LineTypeFee
+	case ledgerv1.LineType_LINE_SPREAD:
+		return model.LineTypeSpread
+	case ledgerv1.LineType_LINE_REVERSAL:
+		return model.LineTypeReversal
+	default:
+		return model.LineTypeMain
+	}
+}
+
+// modelLineTypeToProto converts model LineType to proto LineType
+func modelLineTypeToProto(lt model.LineType) ledgerv1.LineType {
+	switch lt {
+	case model.LineTypeMain:
+		return ledgerv1.LineType_LINE_MAIN
+	case model.LineTypeFee:
+		return ledgerv1.LineType_LINE_FEE
+	case model.LineTypeSpread:
+		return ledgerv1.LineType_LINE_SPREAD
+	case model.LineTypeReversal:
+		return ledgerv1.LineType_LINE_REVERSAL
+	default:
+		return ledgerv1.LineType_LINE_TYPE_UNSPECIFIED
+	}
+}
+
+// modelEntryTypeToProto converts model EntryType to proto EntryType
+func modelEntryTypeToProto(et model.EntryType) ledgerv1.EntryType {
+	switch et {
+	case model.EntryTypeCredit:
+		return ledgerv1.EntryType_ENTRY_CREDIT
+	case model.EntryTypeDebit:
+		return ledgerv1.EntryType_ENTRY_DEBIT
+	case model.EntryTypeTransfer:
+		return ledgerv1.EntryType_ENTRY_TRANSFER
+	case model.EntryTypeFX:
+		return ledgerv1.EntryType_ENTRY_FX
+	case model.EntryTypeFee:
+		return ledgerv1.EntryType_ENTRY_FEE
+	case model.EntryTypeAdjust:
+		return ledgerv1.EntryType_ENTRY_ADJUST
+	case model.EntryTypeReverse:
+		return ledgerv1.EntryType_ENTRY_REVERSE
+	default:
+		return ledgerv1.EntryType_ENTRY_TYPE_UNSPECIFIED
+	}
+}
+
+// calculateBalance computes net balance from a set of posting lines
+func calculateBalance(lines []*model.PostingLine) (decimal.Decimal, error) {
+	balance := decimal.Zero
+	for _, line := range lines {
+		amount, err := parseDecimal(line.Amount)
+		if err != nil {
+			return decimal.Zero, fmt.Errorf("invalid line amount: %w", err)
+		}
+		balance = balance.Add(amount)
+	}
+	return balance, nil
+}
+
+// validateBalanced ensures posting lines sum to zero (double-entry accounting)
+func validateBalanced(lines []*model.PostingLine) error {
+	balance, err := calculateBalance(lines)
+	if err != nil {
+		return err
+	}
+	if !balance.IsZero() {
+		return merrors.InvalidArgument(fmt.Sprintf("journal entry must balance (sum=0), got: %s", balance.String()))
+	}
+	return nil
+}