invoices: Add `paid_timestamp` field.

Fixes: #615

lightningd/invoice.c

@@ -31,6 +31,8 @@ static void json_add_invoice(struct json_result *response,
 		json_add_u64(response, "pay_index", inv->pay_index);
 		json_add_u64(response, "msatoshi_received",
 			     inv->msatoshi_received);
+		json_add_u64(response, "paid_timestamp",
+			     inv->paid_timestamp);
 	}
 	json_add_u64(response, "expiry_time", inv->expiry_time);
 	json_object_end(response);

tests/test_lightningd.py

@@ -743,8 +743,13 @@ class LightningDTests(BaseLightningDTests):
         self.wait_for_routes(l1, [chanid])
 
         inv = l2.rpc.invoice(123000, 'test_pay', 'description')['bolt11']
+        before = int(time.time())
         l1.rpc.pay(inv)
-        assert l2.rpc.listinvoice('test_pay')[0]['complete'] == True
+        after = int(time.time())
+        invoice = l2.rpc.listinvoice('test_pay')[0]
+        assert invoice['complete'] == True
+        assert invoice['paid_timestamp'] >= before
+        assert invoice['paid_timestamp'] <= after
 
         # Repeat payments are NOPs (if valid): we can hand null.
         l1.rpc.pay(inv, None)

wallet/db.c

@@ -177,6 +177,12 @@ char *dbmigrations[] = {
     "ALTER TABLE payments ADD COLUMN payment_preimage BLOB;",
     /* We need to keep the shared secrets to decode error returns. */
     "ALTER TABLE payments ADD COLUMN path_secrets BLOB;",
+    /* Create time-of-payment of invoice, default already-paid
+     * invoices to current time. */
+    "ALTER TABLE invoices ADD paid_timestamp INTEGER;",
+    "UPDATE invoices"
+    "   SET paid_timestamp = strftime('%s', 'now')"
+    " WHERE state = 1;",
     NULL,
 };
 

wallet/invoices.c

@@ -61,8 +61,10 @@ static bool wallet_stmt2invoice(sqlite3_stmt *stmt, struct invoice *inv)
 	/* Correctly 0 if pay_index is NULL. */
 	inv->pay_index = sqlite3_column_int64(stmt, 7);
 
-	if (inv->state == PAID)
+	if (inv->state == PAID) {
 		inv->msatoshi_received = sqlite3_column_int64(stmt, 8);
+		inv->paid_timestamp = sqlite3_column_int64(stmt, 9);
+	}
 
 	list_head_init(&inv->waitone_waiters);
 	return true;
@@ -94,7 +96,7 @@ bool invoices_load(struct invoices *invoices)
 	stmt = db_query(__func__, invoices->db,
 			"SELECT id, state, payment_key, payment_hash"
 			"     , label, msatoshi, expiry_time, pay_index"
-			"     , msatoshi_received"
+			"     , msatoshi_received, paid_timestamp"
 			"  FROM invoices;");
 	if (!stmt) {
 		log_broken(invoices->log, "Could not load invoices");
@@ -148,8 +150,14 @@ const struct invoice *invoices_create(struct invoices *invoices,
 	 * that string for sql injections... */
 	stmt = db_prepare(invoices->db,
 			  "INSERT INTO invoices"
-			  "            (payment_hash, payment_key, state, msatoshi, label, expiry_time, pay_index, msatoshi_received)"
-			  "     VALUES (?, ?, ?, ?, ?, ?, NULL, NULL);");
+			  "            ( payment_hash, payment_key, state"
+			  "            , msatoshi, label, expiry_time"
+			  "            , pay_index, msatoshi_received"
+			  "            , paid_timestamp)"
+			  "     VALUES ( ?, ?, ?"
+			  "            , ?, ?, ?"
+			  "            , NULL, NULL"
+			  "            , NULL);");
 
 	sqlite3_bind_blob(stmt, 1, &rhash, sizeof(rhash), SQLITE_TRANSIENT);
 	sqlite3_bind_blob(stmt, 2, &r, sizeof(r), SQLITE_TRANSIENT);
@@ -274,11 +282,12 @@ void invoices_resolve(struct invoices *invoices,
 	struct invoice_waiter *w;
 	struct invoice *invoice = (struct invoice *)cinvoice;
 	s64 pay_index;
+	u64 paid_timestamp;
 	const tal_t *tmpctx = tal_tmpctx(NULL);
 
 	/* Assign a pay-index. */
 	pay_index = get_next_pay_index(invoices->db);
-	/* FIXME: Save time of payment. */
+	paid_timestamp = time_now().ts.tv_sec;
 
 	/* Update database. */
 	stmt = db_prepare(invoices->db,
@@ -286,17 +295,20 @@ void invoices_resolve(struct invoices *invoices,
 			  "   SET state=?"
 			  "     , pay_index=?"
 			  "     , msatoshi_received=?"
+			  "     , paid_timestamp=?"
 			  " WHERE id=?;");
 	sqlite3_bind_int(stmt, 1, PAID);
 	sqlite3_bind_int64(stmt, 2, pay_index);
 	sqlite3_bind_int64(stmt, 3, msatoshi_received);
-	sqlite3_bind_int64(stmt, 4, invoice->id);
+	sqlite3_bind_int64(stmt, 4, paid_timestamp);
+	sqlite3_bind_int64(stmt, 5, invoice->id);
 	db_exec_prepared(invoices->db, stmt);
 
 	/* Update in-memory structure. */
 	invoice->state = PAID;
 	invoice->pay_index = pay_index;
 	invoice->msatoshi_received = msatoshi_received;
+	invoice->paid_timestamp = paid_timestamp;
 
 	/* Tell all the waitany waiters about the new paid invoice. */
 	while ((w = list_pop(&invoices->waitany_waiters,

wallet/wallet.h

@@ -365,6 +365,8 @@ struct invoice {
 	u64 *msatoshi;
 	/* Set if state == PAID */
 	u64 msatoshi_received;
+	/* Set if state == PAID */
+	u64 paid_timestamp;
 	struct preimage r;
 	u64 expiry_time;
 	struct sha256 rhash;