From c94a49a1fb76d138e1f75144d82826f5eca7997b Mon Sep 17 00:00:00 2001
From: Simon Warta <simon@warta.it>
Date: Mon, 17 Feb 2020 14:27:38 +0100
Subject: [PATCH] Add ERC20 supprt to parseMsg

---
 packages/bcp/src/decode.spec.ts | 55 +++++++++++++++++++++++++++++++--
 packages/bcp/src/decode.ts      | 32 ++++++++++++++++++-
 packages/bcp/types/decode.d.ts  |  3 +-
 3 files changed, 85 insertions(+), 5 deletions(-)

diff --git a/packages/bcp/src/decode.spec.ts b/packages/bcp/src/decode.spec.ts
index dde064c6..b769c00b 100644
--- a/packages/bcp/src/decode.spec.ts
+++ b/packages/bcp/src/decode.spec.ts
@@ -1,7 +1,8 @@
 /* eslint-disable @typescript-eslint/camelcase */
 import { types } from "@cosmwasm/sdk";
-import { Address, Algorithm, SendTransaction, TokenTicker } from "@iov/bcp";
+import { Address, Algorithm, isSendTransaction, SendTransaction, TokenTicker } from "@iov/bcp";
 import { Encoding } from "@iov/encoding";
+import { assert } from "@iov/utils";
 
 import {
   decodeAmount,
@@ -17,7 +18,7 @@ import {
 } from "./decode";
 import * as testdata from "./testdata.spec";
 import cosmoshub from "./testdata/cosmoshub.json";
-import { BankTokens } from "./types";
+import { BankTokens, Erc20Token } from "./types";
 
 const { fromBase64, fromHex } = Encoding;
 
@@ -63,6 +64,23 @@ describe("decode", () => {
       denom: "uatom",
     },
   ];
+  const defaultErc20Tokens: Erc20Token[] = [
+    {
+      contractAddress: "cosmos18vd8fpwxzck93qlwghaj6arh4p7c5n89uzcee5",
+      fractionalDigits: 5,
+      ticker: "ASH",
+    },
+    {
+      contractAddress: "cosmos1hqrdl6wstt8qzshwc6mrumpjk9338k0lr4dqxd",
+      fractionalDigits: 0,
+      ticker: "BASH",
+    },
+    {
+      contractAddress: "cosmos18r5szma8hm93pvx6lwpjwyxruw27e0k5uw835c",
+      fractionalDigits: 18,
+      ticker: "CASH",
+    },
+  ];
 
   describe("decodePubkey", () => {
     it("works for secp256k1", () => {
@@ -126,7 +144,7 @@ describe("decode", () => {
   });
 
   describe("parseMsg", () => {
-    it("works", () => {
+    it("works for bank send transaction", () => {
       const msg: types.Msg = {
         type: "cosmos-sdk/MsgSend",
         value: {
@@ -142,6 +160,37 @@ describe("decode", () => {
       };
       expect(parseMsg(msg, defaultMemo, testdata.chainId, defaultTokens)).toEqual(defaultSendTransaction);
     });
+
+    it("works for ERC20 send transaction", () => {
+      const msg: types.MsgExecuteContract = {
+        type: "wasm/execute",
+        value: {
+          sender: "cosmos1h806c7khnvmjlywdrkdgk2vrayy2mmvf9rxk2r",
+          contract: defaultErc20Tokens[0].contractAddress,
+          msg: {
+            transfer: {
+              amount: "887878484",
+              recipient: "cosmos1z7g5w84ynmjyg0kqpahdjqpj7yq34v3suckp0e",
+            },
+          },
+          sent_funds: [],
+        },
+      };
+      const transaction = parseMsg(msg, defaultMemo, testdata.chainId, defaultTokens, defaultErc20Tokens);
+      assert(isSendTransaction(transaction));
+      expect(transaction).toEqual({
+        kind: "bcp/send",
+        chainId: testdata.chainId,
+        sender: "cosmos1h806c7khnvmjlywdrkdgk2vrayy2mmvf9rxk2r" as Address,
+        recipient: "cosmos1z7g5w84ynmjyg0kqpahdjqpj7yq34v3suckp0e" as Address,
+        amount: {
+          quantity: "887878484",
+          tokenTicker: "ASH" as TokenTicker,
+          fractionalDigits: 5,
+        },
+        memo: defaultMemo,
+      });
+    });
   });
 
   describe("parseFee", () => {
diff --git a/packages/bcp/src/decode.ts b/packages/bcp/src/decode.ts
index b57eb8bd..0aede7e5 100644
--- a/packages/bcp/src/decode.ts
+++ b/packages/bcp/src/decode.ts
@@ -19,8 +19,9 @@ import {
   UnsignedTransaction,
 } from "@iov/bcp";
 import { Decimal, Encoding } from "@iov/encoding";
+import BN from "bn.js";
 
-import { BankTokens } from "./types";
+import { BankTokens, Erc20Token } from "./types";
 
 const { fromBase64 } = Encoding;
 
@@ -76,6 +77,7 @@ export function parseMsg(
   memo: string | undefined,
   chainId: ChainId,
   tokens: BankTokens,
+  erc20Tokens: readonly Erc20Token[] = [],
 ): UnsignedTransaction {
   if (types.isMsgSend(msg)) {
     if (msg.value.amount.length !== 1) {
@@ -90,6 +92,34 @@ export function parseMsg(
       memo: memo,
     };
     return send;
+  } else if (types.isMsgExecuteContract(msg)) {
+    const matchingTokenContract = erc20Tokens.find(t => t.contractAddress === msg.value.contract);
+    if (!matchingTokenContract) {
+      return {
+        chainId: chainId,
+        kind: "bcp/unknown",
+      };
+    }
+
+    const recipient: string | undefined = (msg.value.msg as any).transfer?.recipient;
+    if (!recipient) throw new Error("Could not read recipient");
+
+    const amount: string | undefined = (msg.value.msg as any).transfer?.amount;
+    if (!amount) throw new Error("Could not read recipient");
+
+    const send: SendTransaction = {
+      kind: "bcp/send",
+      chainId: chainId,
+      sender: msg.value.sender as Address,
+      recipient: recipient as Address,
+      amount: {
+        quantity: new BN(amount).toString(),
+        fractionalDigits: matchingTokenContract.fractionalDigits,
+        tokenTicker: matchingTokenContract.ticker as TokenTicker,
+      },
+      memo: memo,
+    };
+    return send;
   } else {
     // Unknown transaction type
     const unknown = {
diff --git a/packages/bcp/types/decode.d.ts b/packages/bcp/types/decode.d.ts
index c895d2a0..95035554 100644
--- a/packages/bcp/types/decode.d.ts
+++ b/packages/bcp/types/decode.d.ts
@@ -13,7 +13,7 @@ import {
   UnsignedTransaction,
 } from "@iov/bcp";
 import { Decimal } from "@iov/encoding";
-import { BankTokens } from "./types";
+import { BankTokens, Erc20Token } from "./types";
 export declare function decodePubkey(pubkey: types.PubKey): PubkeyBundle;
 export declare function decodeSignature(signature: string): SignatureBytes;
 export declare function decodeFullSignature(signature: types.StdSignature, nonce: number): FullSignature;
@@ -24,6 +24,7 @@ export declare function parseMsg(
   memo: string | undefined,
   chainId: ChainId,
   tokens: BankTokens,
+  erc20Tokens?: readonly Erc20Token[],
 ): UnsignedTransaction;
 export declare function parseFee(fee: types.StdFee, tokens: BankTokens): Fee;
 export declare function parseUnsignedTx(