chore: clean up weights + estimates

examples/tx/weights_&_estimates.ts

@@ -0,0 +1,33 @@
+/**
+ * @title Weights & Estimates
+ * @stability nearing
+ * @description Get the timepoint and estimate the fee of a tx.
+ */
+
+import { $weight, westend } from "@capi/westend"
+import { $, alice, Rune } from "capi"
+
+/// Create the call data.
+const call = westend.Balances
+  .transfer({
+    value: 12345n,
+    dest: alice.address,
+  })
+
+/// Gather the weight and estimate.
+const collection = await Rune
+  .object({
+    weight: call.weight(),
+    estimate: call.estimate(),
+  })
+  .run()
+
+/// Ensure the data is of the expected shape.
+console.log(collection)
+$.assert(
+  $.object(
+    $.field("weight", $weight),
+    $.field("estimate", $.u128),
+  ),
+  collection,
+)

fluent/ExtrinsicRune.ts

@@ -50,7 +50,7 @@ export class ExtrinsicRune<out C extends Chain, out U> extends PatternRune<Chain
       .into(SignedExtrinsicRune, this.chain)
   }
 
-  feeEstimate() {
+  weightRaw() {
     const extrinsic = this.chain.$extrinsic.encoded(Rune.object({
       protocolVersion: ExtrinsicRune.PROTOCOL_VERSION,
       call: this,
@@ -59,13 +59,29 @@ export class ExtrinsicRune<out C extends Chain, out U> extends PatternRune<Chain
       .fn(concat)
       .call(extrinsic, extrinsic.access("length").map((n) => $.u32.encode(n)))
       .map(hex.encodePrefixed)
-    const data = this.chain.connection
+    // The TransactionPaymentApi_query_info endpoint returns a heavily-padded hex str.
+    // If we don't strip the excess before passing to other calls, we get a runtime panic.
+    return this.chain.connection
       .call("state_call", "TransactionPaymentApi_query_info", arg)
       .map(hex.decode)
+      .map((v) => v.slice(0, 6))
+      .map(hex.encode)
+  }
+
+  weight() {
     return this.chain.metadata
       .access("paths", "sp_weights::weight_v2::Weight")
-      .map(($c) => $.field("weight", $c))
       .into(CodecRune)
-      .decoded(data)
+      .decoded(this.weightRaw().map(hex.decode))
+  }
+
+  estimate() {
+    const encoded = this.chain.connection
+      .call("state_call", "TransactionPaymentApi_query_weight_to_fee", this.weightRaw())
+      .map(hex.decode)
+    return Rune
+      .constant($.u128)
+      .into(CodecRune)
+      .decoded(encoded)
   }
 }

patterns/multisig/MultisigRune.ts

@@ -59,7 +59,7 @@ export class MultisigRune<out C extends Chain, out U> extends PatternRune<Multis
               threshold,
               call,
               otherSignatories,
-              maxWeight: call.feeEstimate().access("weight"),
+              maxWeight: call.weight(),
               maybeTimepoint,
             }),
         })