channeldb: convert settled boolean to state

This commit is a preparation for the addition of new invoice
states. A database migration is not needed because we keep
the same field length and values.

channeldb/invoice_test.go

@@ -106,7 +106,7 @@ func TestInvoiceWorkflow(t *testing.T) {
 	if err != nil {
 		t.Fatalf("unable to fetch invoice: %v", err)
 	}
-	if !dbInvoice2.Terms.Settled {
+	if dbInvoice2.Terms.State != ContractSettled {
 		t.Fatalf("invoice should now be settled but isn't")
 	}
 	if dbInvoice2.SettleDate.IsZero() {
@@ -348,7 +348,7 @@ func TestDuplicateSettleInvoice(t *testing.T) {
 	// We'll update what we expect the settle invoice to be so that our
 	// comparison below has the correct assumption.
 	invoice.SettleIndex = 1
-	invoice.Terms.Settled = true
+	invoice.Terms.State = ContractSettled
 	invoice.AmtPaid = amt
 	invoice.SettleDate = dbInvoice.SettleDate
 

channeldb/invoices.go

@@ -74,6 +74,30 @@ const (
 	MaxPaymentRequestSize = 4096
 )
 
+// ContractState describes the state the invoice is in.
+type ContractState uint8
+
+const (
+	// ContractOpen means the invoice has only been created.
+	ContractOpen ContractState = 0
+
+	// ContractSettled means the htlc is settled and the invoice has been
+	// paid.
+	ContractSettled ContractState = 1
+)
+
+// String returns a human readable identifier for the ContractState type.
+func (c ContractState) String() string {
+	switch c {
+	case ContractOpen:
+		return "Open"
+	case ContractSettled:
+		return "Settled"
+	}
+
+	return "Unknown"
+}
+
 // ContractTerm is a companion struct to the Invoice struct. This struct houses
 // the necessary conditions required before the invoice can be considered fully
 // settled by the payee.
@@ -87,9 +111,8 @@ type ContractTerm struct {
 	// which can be satisfied by the above preimage.
 	Value lnwire.MilliSatoshi
 
-	// Settled indicates if this particular contract term has been fully
-	// settled by the payer.
-	Settled bool
+	// State describes the state the invoice is in.
+	State ContractState
 }
 
 // Invoice is a payment invoice generated by a payee in order to request
@@ -380,7 +403,9 @@ func (d *DB) FetchAllInvoices(pendingOnly bool) ([]Invoice, error) {
 				return err
 			}
 
-			if pendingOnly && invoice.Terms.Settled {
+			if pendingOnly &&
+				invoice.Terms.State == ContractSettled {
+
 				return nil
 			}
 
@@ -528,7 +553,9 @@ func (d *DB) QueryInvoices(q InvoiceQuery) (InvoiceSlice, error) {
 
 			// Skip any settled invoices if the caller is only
 			// interested in unsettled.
-			if q.PendingOnly && invoice.Terms.Settled {
+			if q.PendingOnly &&
+				invoice.Terms.State == ContractSettled {
+
 				continue
 			}
 
@@ -773,7 +800,7 @@ func serializeInvoice(w io.Writer, i *Invoice) error {
 		return err
 	}
 
-	if err := binary.Write(w, byteOrder, i.Terms.Settled); err != nil {
+	if err := binary.Write(w, byteOrder, i.Terms.State); err != nil {
 		return err
 	}
 
@@ -845,7 +872,7 @@ func deserializeInvoice(r io.Reader) (Invoice, error) {
 	}
 	invoice.Terms.Value = lnwire.MilliSatoshi(byteOrder.Uint64(scratch[:]))
 
-	if err := binary.Read(r, byteOrder, &invoice.Terms.Settled); err != nil {
+	if err := binary.Read(r, byteOrder, &invoice.Terms.State); err != nil {
 		return invoice, err
 	}
 
@@ -872,7 +899,7 @@ func settleInvoice(invoices, settleIndex *bbolt.Bucket, invoiceNum []byte,
 
 	// Add idempotency to duplicate settles, return here to avoid
 	// overwriting the previous info.
-	if invoice.Terms.Settled {
+	if invoice.Terms.State == ContractSettled {
 		return &invoice, nil
 	}
 
@@ -891,7 +918,7 @@ func settleInvoice(invoices, settleIndex *bbolt.Bucket, invoiceNum []byte,
 	}
 
 	invoice.AmtPaid = amtPaid
-	invoice.Terms.Settled = true
+	invoice.Terms.State = ContractSettled
 	invoice.SettleDate = time.Now()
 	invoice.SettleIndex = nextSettleSeqNo
 

channeldb/migrations.go

@@ -189,7 +189,7 @@ func migrateInvoiceTimeSeries(tx *bbolt.Tx) error {
 		// Next, we'll check if the invoice has been settled or not. If
 		// so, then we'll also add it to the settle index.
 		var nextSettleSeqNo uint64
-		if invoice.Terms.Settled {
+		if invoice.Terms.State == ContractSettled {
 			nextSettleSeqNo, err = settleIndex.NextSequence()
 			if err != nil {
 				return err