Merge pull request #13 from uma-universal-money-address/fix/paymentin…

…fodecimals

Some tweaks to the payment_info in payreq response.

src/currency.rs

@@ -33,5 +33,5 @@ pub struct Currency {
     // means. For example, if the currency is "BTC" and the multiplier is 1000, really we're exchanging in SATs, so
     // `decimals` would be 8.
     // For details on edge cases and examples, see https://github.com/uma-universal-money-address/protocol/blob/main/umad-04-lnurlp-response.md.
-    pub decimals: i64,
+    pub decimals: i32,
 }

src/protocol.rs

@@ -194,7 +194,7 @@ impl PayRequest {
 }
 
 /// PayReqResponse is the response sent by the receiver to the sender to provide an invoice.
-#[derive(Serialize, Deserialize, Debug, Clone, PartialEq, Eq)]
+#[derive(Serialize, Deserialize, Debug, Clone, PartialEq)]
 pub struct PayReqResponse {
     /// encoded_invoice is the BOLT11 invoice that the sender will pay.
     #[serde(rename = "pr")]
@@ -240,17 +240,24 @@ pub struct PayReqResponseCompliance {
     pub utxo_callback: String,
 }
 
-#[derive(Serialize, Deserialize, Debug, Clone, PartialEq, Eq)]
+#[derive(Serialize, Deserialize, Debug, Clone, PartialEq)]
 pub struct PayReqResponsePaymentInfo {
     /// CurrencyCode is the ISO 3-digit currency code that the receiver will receive for this
     /// payment.
     #[serde(rename = "currencyCode")]
     pub currency_code: String,
 
+    /// Number of digits after the decimal point for the receiving currency. For example, in USD, by
+    /// convention, there are 2 digits for cents - $5.95. In this case, `decimals` would be 2. This should align with
+    /// the currency's `decimals` field in the LNURLP response. It is included here for convenience. See
+    /// [UMAD-04](https://github.com/uma-universal-money-address/protocol/blob/main/umad-04-lnurlp-response.md) for
+    /// details, edge cases, and examples.
+    pub decimals: i32,
+
     /// Multiplier is the conversion rate. It is the number of millisatoshis that the receiver will
     /// receive for 1 unit of the specified currency.
     #[serde(rename = "multiplier")]
-    pub multiplier: i64,
+    pub multiplier: f64,
 
     /// ExchangeFeesMillisatoshi is the fees charged (in millisats) by the receiving VASP for this
     /// transaction. This is separate from the Multiplier.

src/uma.rs

@@ -467,7 +467,8 @@ pub fn get_pay_req_response<T>(
     invoice_creator: &T,
     metadata: &str,
     currency_code: &str,
-    conversion_rate: i64,
+    currency_decimals: i32,
+    conversion_rate: f64,
     receiver_fees_millisats: i64,
     receiver_channel_utxos: &[String],
     receiver_node_pub_key: Option<&str>,
@@ -476,7 +477,8 @@ pub fn get_pay_req_response<T>(
 where
     T: UmaInvoiceCreator,
 {
-    let msats_amount = query.amount * conversion_rate + receiver_fees_millisats;
+    let msats_amount =
+        (query.amount as f64 * conversion_rate).round() as i64 + receiver_fees_millisats;
     let encoded_payer_data =
         serde_json::to_string(&query.payer_data).map_err(Error::InvalidData)?;
     let encoded_invoice = invoice_creator
@@ -496,6 +498,7 @@ where
         },
         payment_info: PayReqResponsePaymentInfo {
             currency_code: currency_code.to_string(),
+            decimals: currency_decimals,
             multiplier: conversion_rate,
             exchange_fees_millisatoshi: receiver_fees_millisats,
         },

src/uma_test.rs

@@ -248,7 +248,8 @@ mod tests {
             &client,
             &metadata,
             "USD",
-            34150,
+            2,
+            23150.0,
             100_000,
             &["abcdef12345".to_owned()],
             None,

src/version.rs

@@ -1,7 +1,7 @@
 use crate::uma;
 
 const MAJOR_VERSION: i32 = 0;
-const MINOR_VERSION: i32 = 2;
+const MINOR_VERSION: i32 = 3;
 
 pub fn uma_protocol_version() -> String {
     format!("{}.{}", MAJOR_VERSION, MINOR_VERSION)