fix(mock): carry the requested amount in the invoice prefix (0.3.2)

CHANGELOG.md

@@ -1,5 +1,15 @@
 # Changelog
 
+## 0.3.2 — 2026-09-26
+
+### Fixed
+- **A mock invoice's prefix now carries the amount it charges.** Every invoice began `lnbc10n`
+  (1 sat) whatever `amountSat` was requested, so a consumer reading the price off the invoice saw
+  1 sat. imani-gateway-core checks that a client mint's invoice charges what the sale costs
+  (imani-gateway-core#92), and refused every staging client mint because of it. The prefix is now
+  `lnbc{amountSat × 10}n`, the nano-BTC form of the requested amount, and an amount of zero or
+  less is written as an amountless invoice. The invoice is still not signed or payable.
+
 ## 0.3.1 — 2026-09-23
 
 ### Fixed

phoenixd-base/pom.xml

@@ -4,7 +4,7 @@
     <parent>
         <groupId>xyz.tcheeric</groupId>
         <artifactId>phoenixd-java</artifactId>
-        <version>0.3.1</version>
+        <version>0.3.2</version>
     </parent>
 
     <artifactId>phoenixd-base</artifactId>

phoenixd-mock/pom.xml

@@ -6,7 +6,7 @@
     <parent>
         <groupId>xyz.tcheeric</groupId>
         <artifactId>phoenixd-java</artifactId>
-        <version>0.3.1</version>
+        <version>0.3.2</version>
     </parent>
 
     <artifactId>phoenixd-mock</artifactId>

phoenixd-mock/src/main/java/xyz/tcheeric/phoenixd/mock/MockLnServer.java

@@ -157,7 +157,7 @@
         String externalId = null;
         long amountSat = 10;
 
         if (body != null && !body.isEmpty()) {
             for (String param : body.split("&")) {
                 String[] pair = param.split("=", 2);
                 if (pair.length == 2) {
@@ -176,14 +176,14 @@
         // Generate a unique mock bolt11 invoice with valid Bech32 encoding
         String invoiceId = Long.toHexString(System.nanoTime());
         String paymentHash = "hash" + invoiceId;
-        String bolt11 = generateValidBolt11Invoice();
+        String bolt11 = generateValidBolt11Invoice(amountSat);
 
         // Track the invoice for auto-settlement
         InvoiceInfo invoiceInfo = new InvoiceInfo(paymentHash, bolt11, amountSat, externalId);
         invoices.put(paymentHash, invoiceInfo);
 
         // Also index by external ID (quote ID) for mockpay lookup
         if (externalId != null && !externalId.isEmpty()) {
             invoicesByExternalId.put(externalId, invoiceInfo);
         }
 
@@ -241,10 +241,14 @@
      *
      * This generates a mock invoice that passes basic Bech32 validation but is not
      * cryptographically valid for actual Lightning Network payments.
+     *
+     * <p>The human-readable part carries the requested amount, as a real invoice does. It used
+     * to be a fixed {@code lnbc10n} (1 sat) whatever was asked for, so anything that reads the
+     * price off the invoice, such as imani-gateway-core's check that a client mint charged what
+     * the sale costs, refused every invoice this mock issued.
      */
-    private String generateValidBolt11Invoice() {
-        // Human-readable part: ln + bc (bitcoin mainnet) + 10n (10 nanosats = ~0 sats for testing)
-        String hrp = "lnbc10n";
+    String generateValidBolt11Invoice(long amountSat) {
+        String hrp = "lnbc" + bolt11Amount(amountSat);
 
         // Generate random payment hash (32 bytes = 52 chars in bech32, roughly)
         // For a minimal valid invoice, we need at least timestamp + payment hash
@@ -262,6 +266,14 @@
         return hrp + "1" + data + checksum;
     }
 
+    /**
+     * The BOLT11 amount for a whole number of sats. With the {@code n} (nano-BTC) multiplier one
+     * sat is 10 units. Zero or less is an amountless invoice, which BOLT11 writes as no amount.
+     */
+    static String bolt11Amount(long amountSat) {
+        return amountSat > 0 ? (amountSat * 10) + "n" : "";
+    }
+
     /**
      * Calculates Bech32 checksum for the given HRP and data.
      * Simplified implementation for mock purposes.
@@ -325,7 +337,7 @@
         String body = new String(exchange.getRequestBody().readAllBytes(), StandardCharsets.UTF_8);
         String invoice = null;
 
         if (body != null && !body.isEmpty()) {
             for (String param : body.split("&")) {
                 String[] pair = param.split("=", 2);
                 if (pair.length == 2 && "invoice".equals(pair[0])) {

phoenixd-mock/src/test/java/xyz/tcheeric/phoenixd/mock/MockLnServerTest.java

@@ -97,6 +97,31 @@ void shouldCreateInvoiceWithDefaultAmount() throws Exception {
         assertThat(bolt11).startsWith("lnbc");
     }
 
+    // The invoice charges what was asked for: 500 sat is 5000 nano-BTC in the BOLT11 prefix, so
+    // a consumer reading the price off the invoice sees 500, not the 1 sat the prefix used to say.
+    @Test
+    void createdInvoiceCarriesTheRequestedAmountInItsPrefix() throws Exception {
+        HttpRequest request = HttpRequest.newBuilder()
+                .uri(URI.create(BASE_URL + "/createinvoice"))
+                .header("Content-Type", "application/x-www-form-urlencoded")
+                .POST(HttpRequest.BodyPublishers.ofString("amountSat=500"))
+                .build();
+
+        HttpResponse<String> response = httpClient.send(request, HttpResponse.BodyHandlers.ofString());
+
+        String bolt11 = objectMapper.readTree(response.body()).get("serialized").asText();
+        assertThat(bolt11).startsWith("lnbc5000n1");
+    }
+
+    // One sat is ten nano-BTC, and a non-positive amount is written as no amount at all.
+    @Test
+    void bolt11AmountEncodesWholeSatsWithTheNanoMultiplier() {
+        assertThat(MockLnServer.bolt11Amount(1)).isEqualTo("10n");
+        assertThat(MockLnServer.bolt11Amount(100)).isEqualTo("1000n");
+        assertThat(MockLnServer.bolt11Amount(0)).isEmpty();
+        assertThat(MockLnServer.bolt11Amount(-3)).isEmpty();
+    }
+
     @Test
     void shouldGetInvoiceStatus() throws Exception {
         // Arrange: Create an invoice first

phoenixd-model/pom.xml

@@ -4,7 +4,7 @@
     <parent>
         <groupId>xyz.tcheeric</groupId>
         <artifactId>phoenixd-java</artifactId>
-        <version>0.3.1</version>
+        <version>0.3.2</version>
     </parent>
 
     <artifactId>phoenixd-model</artifactId>

phoenixd-rest/pom.xml

@@ -4,12 +4,12 @@
     <parent>
         <groupId>xyz.tcheeric</groupId>
         <artifactId>phoenixd-java</artifactId>
-        <version>0.3.1</version>
+        <version>0.3.2</version>
     </parent>
 
     <artifactId>phoenixd-rest</artifactId>
     <packaging>jar</packaging>
-    <version>0.3.1</version>
+    <version>0.3.2</version>
     <name>phoenixd-rest</name>
     <url>https://maven.apache.org</url>
 

phoenixd-test/pom.xml

@@ -4,7 +4,7 @@
     <parent>
         <groupId>xyz.tcheeric</groupId>
         <artifactId>phoenixd-java</artifactId>
-        <version>0.3.1</version>
+        <version>0.3.2</version>
     </parent>
 
     <artifactId>phoenixd-test</artifactId>

pom.xml

@@ -3,7 +3,7 @@
     <modelVersion>4.0.0</modelVersion>
     <groupId>xyz.tcheeric</groupId>
     <artifactId>phoenixd-java</artifactId>
-    <version>0.3.1</version>
+    <version>0.3.2</version>
     <packaging>pom</packaging>
 
     <modules>