feat(stream): add Connection#pay() method which auto-manages stream

packages/lib-protocol-stream/src/connection/connection.ts

@@ -5,6 +5,7 @@ import { Stream } from "../stream/stream"
 import type { EventEmitter } from "../types/event-emitter"
 import { closeConnection } from "./close"
 import { createStream } from "./create-stream"
+import { makePayment } from "./make-payment"
 import { measureExchangeRate } from "./measure-exchange-rate"
 import { sendUntilDone } from "./send-until-done"
 import {
@@ -14,6 +15,10 @@ import {
 } from "./set-exchange-rate"
 import type { ConnectionEvents, ConnectionState } from "./state"
 
+interface PayOptions {
+  sourceAmountLimit: bigint
+}
+
 export class Connection implements EventEmitter<ConnectionEvents> {
   constructor(private readonly state: ConnectionState) {}
 
@@ -39,6 +44,10 @@ export class Connection implements EventEmitter<ConnectionEvents> {
     return new Stream(this.state, streamState, streamId)
   }
 
+  pay({ sourceAmountLimit }: PayOptions) {
+    return makePayment({ state: this.state, sourceAmountLimit })
+  }
+
   async close() {
     return closeConnection(this.state)
   }

packages/lib-protocol-stream/src/connection/make-payment.ts

@@ -0,0 +1,30 @@
+import { isFailure } from "@dassie/lib-type-utils"
+
+import { closeStream } from "../stream/close"
+import { sendAndAwait } from "../stream/send-and-await"
+import { createStream } from "./create-stream"
+import type { ConnectionState } from "./state"
+
+interface MakePaymentOptions {
+  state: ConnectionState
+  sourceAmountLimit: bigint
+}
+
+export async function makePayment({
+  state,
+  sourceAmountLimit,
+}: MakePaymentOptions) {
+  const { streamId, streamState } = createStream({ state })
+
+  const result = await sendAndAwait({
+    connectionState: state,
+    state: streamState,
+    amount: sourceAmountLimit,
+  })
+
+  if (isFailure(result)) return result
+
+  closeStream(streamId, state, streamState)
+
+  return
+}

packages/lib-protocol-stream/src/test/connection.test.ts

@@ -177,9 +177,7 @@ describe("Connection", () => {
       })
     })
 
-    const stream = client.createStream()
-
-    unwrapFailure(await stream.send({ amount: 1_000_000n }))
+    unwrapFailure(await client.pay({ sourceAmountLimit: 1_000_000n }))
 
     expect(moneyReceived).toBe(1_000_000n)