feat: add decode transactions

package.json

@@ -25,6 +25,9 @@
     "typescript": "^4.6.3",
     "yargs": "^17.4.0"
   },
+  "dependencies": {
+    "@stacks/stacks-blockchain-api-types": "^3.0.2"
+  },
   "peerDependencies": {
     "@stacks/transactions": "*"
   }

src/index.ts

@@ -1,2 +1,3 @@
 export * from "./runtime/contractBase";
 export * from "./runtime/transcoders";
+export * from "./runtime/decodeContractCallTransaction";

src/runtime/contractBase.ts

@@ -61,12 +61,14 @@ export type ReturnTypeOfDescriptor<D> = D extends FunctionDescriptor
     : never
   : never;
 
+export type ContractBaseType = {
+  [contracts: string]: {
+    [func: string]: FunctionDescriptor;
+  };
+};
+
 export function defineContract<
-  T extends {
-    [contracts: string]: {
-      [func: string]: FunctionDescriptor;
-    };
-  }
+  T extends ContractBaseType
 >(contracts: T): T {
   return contracts;
 }

src/runtime/decodeContractCallTransaction.ts

@@ -0,0 +1,91 @@
+import { ContractCallTransaction } from "@stacks/stacks-blockchain-api-types";
+import { deserializeCV } from "@stacks/transactions";
+import {
+  ContractBaseType,
+  FunctionDescriptor,
+  ParameterObjOfDescriptor,
+  ReturnTypeOfDescriptor,
+} from "./contractBase";
+
+export type ContractCallTransactionResultMap<Contracts extends ContractBaseType> = {
+  [C in keyof Contracts]: {
+    [F in keyof Contracts[C]]: {
+      contractName: C;
+      functionName: F;
+      args: ParameterObjOfDescriptor<Contracts[C][F]>;
+      result: ReturnTypeOfDescriptor<Contracts[C][F]>;
+    };
+  };
+};
+
+export type ContractCallTransactionResult<Contracts extends ContractBaseType> = {
+  [K in keyof ContractCallTransactionResultMap<Contracts>]: ContractCallTransactionResultMap<Contracts>[K][keyof ContractCallTransactionResultMap<Contracts>[K]];
+}[keyof ContractCallTransactionResultMap<Contracts>];
+
+export function decodeContractCallTransaction<
+  Contracts extends ContractBaseType
+>(
+  contracts: Contracts,
+  tx: ContractCallTransaction
+): ContractCallTransactionResult<Contracts> {
+  if (!(tx.contract_call.contract_id in contracts)) {
+    throw new Error(
+      `[decodeContractCallTransaction] unknown contract id ${tx.contract_call.contract_id}`
+    );
+  }
+  const contractName = tx.contract_call.contract_id as keyof Contracts;
+
+  if (!(tx.contract_call.function_name in contracts[contractName])) {
+    throw new Error(
+      `[decodeContractCallTransaction] unknown function name ${contractName}.${tx.contract_call.function_name}`
+    );
+  }
+  const functionName = tx.contract_call
+    .function_name as keyof Contracts[keyof Contracts];
+
+  return {
+    contractName,
+    functionName,
+    ...decodeSpecifiedContractCallTransaction(
+      contracts,
+      contractName,
+      functionName,
+      tx
+    ),
+  };
+}
+
+export function decodeSpecifiedContractCallTransaction<
+  Contracts extends ContractBaseType,
+  T extends keyof Contracts,
+  F extends keyof Contracts[T]
+>(
+  contracts: Contracts,
+  contractOrType: T,
+  functionName: F,
+  tx: ContractCallTransaction
+): {
+  args: ParameterObjOfDescriptor<Contracts[T][F]>;
+  result: ReturnTypeOfDescriptor<Contracts[T][F]>;
+  raw: ContractCallTransaction;
+} {
+  const functionDescriptor = contracts[contractOrType][
+    functionName
+  ] as any as FunctionDescriptor;
+
+  const args = functionDescriptor.input.reduce(
+    (acc, arg, index) => ({
+      ...acc,
+      [arg.name]: arg.type.decode(
+        deserializeCV(tx.contract_call.function_args![index]!.hex)
+      ),
+    }),
+    {} as Record<string, any>
+  );
+
+  const result = functionDescriptor.output.decode(
+    deserializeCV(tx.tx_result.hex)
+  );
+
+  return { args: args as any, result, raw: tx };
+}

yarn.lock

@@ -29,6 +29,11 @@
   dependencies:
     "@stacks/common" "^3.3.0"
 
+"@stacks/stacks-blockchain-api-types@^3.0.2":
+  version "3.0.2"
+  resolved "https://registry.yarnpkg.com/@stacks/stacks-blockchain-api-types/-/stacks-blockchain-api-types-3.0.2.tgz#f291f4f0cd28b26b9007debd16c688ca6e20a724"
+  integrity sha512-HurLltAqFVP2raQim9iQ6Gf0QH76hvfA22vHBeCf8lcU//4tw4MvFtPxl/MkspH4BqaoM+yqJ7rHpRV9TDgCCg==
+
 "@stacks/transactions@^3.3.0":
   version "3.3.0"
   resolved "https://registry.yarnpkg.com/@stacks/transactions/-/transactions-3.3.0.tgz#ccc489196dc406d06271631f28f41937b96de897"