add: store coin transfer source

crates/core/src/model/economy.rs

@@ -58,6 +58,16 @@ pub enum CoinTransferMethod {
     Purchase(usize),
 }
 
+#[derive(Serialize, Deserialize)]
+pub enum CoinTransferSource {
+    /// An unknown source, such as a transfer request.
+    General,
+    /// A product sale.
+    Sale,
+    /// A purchase of coins through Stripe.
+    Purchase,
+}
+
 #[derive(Serialize, Deserialize)]
 pub struct CoinTransfer {
     pub id: usize,
@@ -67,11 +77,18 @@ pub struct CoinTransfer {
     pub amount: i32,
     pub is_pending: bool,
     pub method: CoinTransferMethod,
+    pub source: CoinTransferSource,
 }
 
 impl CoinTransfer {
     /// Create a new [`CoinTransfer`].
-    pub fn new(sender: usize, receiver: usize, amount: i32, method: CoinTransferMethod) -> Self {
+    pub fn new(
+        sender: usize,
+        receiver: usize,
+        amount: i32,
+        method: CoinTransferMethod,
+        source: CoinTransferSource,
+    ) -> Self {
         Self {
             id: Snowflake::new().to_string().parse::<usize>().unwrap(),
             created: unix_epoch_timestamp(),
@@ -80,6 +97,7 @@ impl CoinTransfer {
             amount,
             is_pending: false,
             method,
+            source,
         }
     }