From 1d7744a69afeebcc655ebba3004c875a7e2b2b1e Mon Sep 17 00:00:00 2001
From: Mikko Ohtamaa <mikko@opensourcehacker.com>
Date: Wed, 12 Jul 2023 23:17:21 +0200
Subject: [PATCH] Add eth_defi.enzyme.erc_20 helpers

---
 CHANGELOG.md                  |  9 +++--
 eth_defi/enzyme/erc20.py      | 67 +++++++++++++++++++++++++++++++++++
 eth_defi/enzyme/uniswap_v2.py |  2 ++
 3 files changed, 76 insertions(+), 2 deletions(-)
 create mode 100644 eth_defi/enzyme/erc20.py

diff --git a/CHANGELOG.md b/CHANGELOG.md
index bbbafb7b..15b58fae 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,7 +1,12 @@
+# 0.21.4
+
+- Added `eth_defi.enzyme.erc_20` helpers
+
 # 0.21.3
 
-- Fix error message `fetch_transaction_revert_reason()` crashing
-- 
+- Fix error message `fetch_transaction_revert_reason()` crashing. 
+  Also made the error message prettier and more helpful.
+
 # 0.21.2
 
 - Add `AssetDelta.__mul__` method
diff --git a/eth_defi/enzyme/erc20.py b/eth_defi/enzyme/erc20.py
new file mode 100644
index 00000000..1fc9b9ab
--- /dev/null
+++ b/eth_defi/enzyme/erc20.py
@@ -0,0 +1,67 @@
+"""Enzyme vault ERC-20 helpers."""
+from eth_typing import HexAddress
+from web3.contract import Contract
+from web3.contract.contract import ContractFunction
+
+from eth_defi.abi import encode_function_call
+from eth_defi.enzyme.deployment import EnzymeDeployment
+from eth_defi.enzyme.generic_adapter import execute_calls_for_generic_adapter
+from eth_defi.enzyme.vault import Vault
+
+
+def prepare_transfer(
+        enzyme: EnzymeDeployment,
+        vault: Vault,
+        generic_adapter: Contract,
+        token: Contract,
+        receiver: HexAddress | str,
+        amount: int) -> ContractFunction:
+    """Prepare an ERC-20 transfer out from the Enzyme vault.
+
+    - Tells the Enzyme vault to move away som etokes
+
+    :param enzyme:
+        Enzyme deploymeent
+
+    :param vault:
+        Vault that needs to perform the swap
+
+    :param generic_adapter:
+        GenericAdapter contract we use for swaps
+
+    :param token:
+        ERC-20 token we send
+
+    :param receiver:
+        The receiver of tokens
+
+    :param amount:
+        Token amount, raw
+
+    :return:
+        Transaction object that can be signed and executed
+    """
+
+    # Prepare the swap parameters
+    spend_asset_amounts = [amount]
+    spend_assets = [token.address]
+    incoming_assets = []
+    min_incoming_assets_amounts = []
+
+    # The vault performs a swap on Uniswap v2
+    encoded_transfer = encode_function_call(token.functions.transfer, [receiver, amount])
+
+    bound_call = execute_calls_for_generic_adapter(
+        comptroller=vault.comptroller,
+        external_calls=(
+            (token, encoded_transfer),
+        ),
+        generic_adapter=generic_adapter,
+        incoming_assets=incoming_assets,
+        integration_manager=enzyme.contracts.integration_manager,
+        min_incoming_asset_amounts=min_incoming_assets_amounts,
+        spend_asset_amounts=spend_asset_amounts,
+        spend_assets=spend_assets,
+    )
+
+    return bound_call
diff --git a/eth_defi/enzyme/uniswap_v2.py b/eth_defi/enzyme/uniswap_v2.py
index f6bf308c..9e17bc12 100644
--- a/eth_defi/enzyme/uniswap_v2.py
+++ b/eth_defi/enzyme/uniswap_v2.py
@@ -99,3 +99,5 @@ def prepare_swap(enzyme: EnzymeDeployment, vault: Vault, uniswap_v2: UniswapV2De
     )
 
     return bound_call
+
+