use new method in view

apps/block_scout_web/lib/block_scout_web/templates/transaction/overview.html.eex

@@ -169,39 +169,22 @@
       </div>
     </div>
 
-    <%= cond do %>
-      <% erc20_token_transfer = assigns[:token_transfers] && erc20_token_transfer(@transaction, @token_transfers) -> %>
-
+    <%= case token_transfer_type(@transaction) do %>
+      <% {type, token_transfer} -> %>
         <div class="col-md-12 col-lg-4 d-flex flex-column flex-md-row flex-lg-column pl-0">
         <!-- Value -->
         <div class="card card-background-1 flex-grow-1">
           <div class="card-body card-body-flex-column-space-between">
-            <h2 class="card-title balance-card-title"><%= gettext "ERC-20" %> <%= gettext "Token Transfer" %></h2>
+            <h2 class="card-title balance-card-title"><%= if type == :erc20, do: gettext("ERC-20"), else: gettext("ERC-721")%><%= gettext " Token Transfer" %></h2>
             <div class="text-right">
               <h3 class="address-balance-text">
-                  <%= token_transfer_amount(erc20_token_transfer) %>
-                  <%= link(token_symbol(erc20_token_transfer.token), to: token_path(BlockScoutWeb.Endpoint, :show, erc20_token_transfer.token.contract_address_hash)) %>
-              </h3>
-            </div>
-          </div>
-        </div>
-      <% erc721_token_transfer = assigns[:token_transfers] && erc721_token_transfer(@transaction, @token_transfers) -> %>
-        <div class="col-md-12 col-lg-4 d-flex flex-column flex-md-row flex-lg-column">
-        <!-- Value -->
-        <div class="card card-primary flex-grow-1">
-          <div class="card-body">
-            <h2 class="card-title text-white"><%= gettext "ERC-721" %> <%= gettext "Token Transfer" %></h2>
-            <div class="text-right">
-              <h3 class="text-white">
-                <span class="col-12 col-md-7 ml-3 ml-sm-0">
-                  <%= token_transfer_amount(erc721_token_transfer) %>
-                  <%= link(token_symbol(erc721_token_transfer.token), to: token_path(BlockScoutWeb.Endpoint, :show, erc721_token_transfer.token.contract_address_hash)) %>
-                </span>
+                  <%= token_transfer_amount(token_transfer) %>
+                  <%= link(token_symbol(token_transfer.token), to: token_path(BlockScoutWeb.Endpoint, :show, token_transfer.token.contract_address_hash)) %>
               </h3>
             </div>
           </div>
         </div>
-      <% true -> %>
+      <% _ -> %>
         <div class="col-md-12 col-lg-4 d-flex flex-column flex-md-row flex-lg-column pl-0-md">
         <!-- Value -->
         <div class="card card-background-1 flex-grow-1">

apps/block_scout_web/lib/block_scout_web/views/transaction_view.ex

@@ -1,12 +1,11 @@
 defmodule BlockScoutWeb.TransactionView do
   use BlockScoutWeb, :view
 
-  alias ABI.TypeDecoder
   alias BlockScoutWeb.{AddressView, BlockView, TabHelpers}
   alias Cldr.Number
   alias Explorer.Chain
   alias Explorer.Chain.Block.Reward
-  alias Explorer.Chain.{Address, Block, InternalTransaction, TokenTransfer, Transaction, Wei}
+  alias Explorer.Chain.{Address, Block, InternalTransaction, Transaction, Wei}
   alias Explorer.ExchangeRates.Token
   alias Timex.Duration
 
@@ -33,85 +32,10 @@ defmodule BlockScoutWeb.TransactionView do
 
   def value_transfer?(_), do: false
 
-  def erc20_token_transfer(
-        %Transaction{
-          status: :ok,
-          created_contract_address_hash: nil,
-          input: input,
-          value: value
-        },
-        token_transfers
-      ) do
-    zero_wei = %Wei{value: Decimal.new(0)}
-
-    case {to_string(input), value} do
-      {unquote(TokenTransfer.transfer_function_signature()) <> params, ^zero_wei} ->
-        types = [:address, {:uint, 256}]
-
-        [address, value] = decode_params(params, types)
-
-        decimal_value = Decimal.new(value)
-
-        Enum.find(token_transfers, fn token_transfer ->
-          token_transfer.to_address_hash.bytes == address && token_transfer.amount == decimal_value
-        end)
-
-      _ ->
-        nil
-    end
-  rescue
-    _ -> nil
-  end
-
-  def erc20_token_transfer(_, _) do
-    nil
-  end
-
-  def erc721_token_transfer(
-        %Transaction{
-          status: :ok,
-          created_contract_address_hash: nil,
-          input: input,
-          value: value
-        },
-        token_transfers
-      ) do
-    zero_wei = %Wei{value: Decimal.new(0)}
-
-    # https://github.com/OpenZeppelin/openzeppelin-solidity/blob/master/contracts/token/ERC721/ERC721.sol#L35
-    {from_address, to_address} =
-      case {to_string(input), value} do
-        # transferFrom(address,address,uint256)
-        {"0x23b872dd" <> params, ^zero_wei} ->
-          types = [:address, :address, {:uint, 256}]
-          [from_address, to_address, _value] = decode_params(params, types)
-          {from_address, to_address}
-
-        # safeTransferFrom(address,address,uint256)
-        {"0x42842e0e" <> params, ^zero_wei} ->
-          types = [:address, :address, {:uint, 256}]
-          [from_address, to_address, _value] = decode_params(params, types)
-          {from_address, to_address}
-
-        # safeTransferFrom(address,address,uint256,bytes)
-        {"0xb88d4fde" <> params, ^zero_wei} ->
-          types = [:address, :address, {:uint, 256}, :bytes]
-          [from_address, to_address, _value, _data] = decode_params(params, types)
-          {from_address, to_address}
-
-        _ ->
-          nil
-      end
-
-    Enum.find(token_transfers, fn token_transfer ->
-      token_transfer.from_address_hash.bytes == from_address && token_transfer.to_address_hash.bytes == to_address
-    end)
-  rescue
-    _ -> nil
+  def token_transfer_type(transaction) do
+    Chain.transaction_token_transfer_type(transaction)
   end
 
-  def erc721_token_transfer(_, _), do: nil
-
   def processing_time_duration(%Transaction{block: nil}) do
     :pending
   end
@@ -339,10 +263,4 @@ defmodule BlockScoutWeb.TransactionView do
   defp tab_name(["internal_transactions"]), do: gettext("Internal Transactions")
   defp tab_name(["logs"]), do: gettext("Logs")
   defp tab_name(["raw_trace"]), do: gettext("Raw Trace")
-
-  defp decode_params(params, types) do
-    params
-    |> Base.decode16!(case: :mixed)
-    |> TypeDecoder.decode_raw(types)
-  end
 end

apps/block_scout_web/test/block_scout_web/views/transaction_view_test.exs

@@ -47,30 +47,6 @@ defmodule BlockScoutWeb.TransactionViewTest do
     end
   end
 
-  describe "erc721_token_transfer/2" do
-    test "finds token transfer" do
-      from_address_hash = "0x7a30272c902563b712245696f0a81c5a0e45ddc8"
-      to_address_hash = "0xb544cead8b660aae9f2e37450f7be2ffbc501793"
-      from_address = insert(:address, hash: from_address_hash)
-      to_address = insert(:address, hash: to_address_hash)
-      block = insert(:block)
-
-      transaction =
-        insert(:transaction,
-          input:
-            "0x23b872dd0000000000000000000000007a30272c902563b712245696f0a81c5a0e45ddc8000000000000000000000000b544cead8b660aae9f2e37450f7be2ffbc5017930000000000000000000000000000000000000000000000000000000000000002",
-          value: Decimal.new(0),
-          created_contract_address_hash: nil
-        )
-        |> with_block(block, status: :ok)
-
-      token_transfer =
-        insert(:token_transfer, from_address: from_address, to_address: to_address, transaction: transaction)
-
-      assert TransactionView.erc721_token_transfer(transaction, [token_transfer]) == token_transfer
-    end
-  end
-
   describe "processing_time_duration/2" do
     test "returns :pending if the transaction has no block" do
       transaction = build(:transaction, block: nil)

apps/explorer/lib/explorer/chain.ex

@@ -2833,10 +2833,7 @@ defmodule Explorer.Chain do
       ) do
     zero_wei = %Wei{value: Decimal.new(0)}
 
-    transaction =
-      if Ecto.assoc_loaded?(transaction.token_transfers),
-        do: transaction,
-        else: Repo.preload(transaction, :token_transfers)
+    transaction = Repo.preload(transaction, token_transfers: :token)
 
     # https://github.com/OpenZeppelin/openzeppelin-solidity/blob/master/contracts/token/ERC721/ERC721.sol#L35
     case {to_string(input), value} do
@@ -2890,17 +2887,16 @@ defmodule Explorer.Chain do
   end
 
   defp find_erc721_or_erc20_token_transfer(token_transfers, {address, decimal_value}) do
-    IO.inspect({address, decimal_value})
-
     token_transfer =
       Enum.find(token_transfers, fn token_transfer ->
-        token_transfer.to_address_hash.bytes == address && token_transfer.amount == decimal_value
+        token_transfer.to_address_hash.bytes == address &&
+          (token_transfer.amount == decimal_value || token_transfer.token_id)
       end)
 
     if token_transfer do
-      case token_from_address_hash(token_transfer.token_contract_address_hash) do
-        {:ok, %Token{type: "ERC-20"}} -> {:erc20, token_transfer}
-        {:ok, %Token{type: "ERC-721"}} -> {:erc721, token_transfer}
+      case token_transfer.token do
+        %Token{type: "ERC-20"} -> {:erc20, token_transfer}
+        %Token{type: "ERC-721"} -> {:erc721, token_transfer}
         _ -> nil
       end
     end