add tabs

apps/block_scout_web/lib/block_scout_web/templates/tokens/instance/overview/_tabs.html.eex

@@ -0,0 +1,15 @@
+<div class="card-tabs js-card-tabs">
+  <%= link(
+        gettext("Token Transfers"),
+        class: "card-tab #{tab_status("token_transfers", @conn.request_path)}",
+        to: token_path(@conn, :show, @token.contract_address_hash)
+      )
+    %>
+  <%= if smart_contract_with_read_only_functions?(@token) do %>
+    <%= link(
+        gettext("Read Contract"),
+        to: token_read_contract_path(@conn, :index, @token.contract_address_hash),
+        class: "card-tab #{tab_status("read_contract", @conn.request_path)}")
+      %>
+  <% end %>
+</div>

apps/block_scout_web/lib/block_scout_web/views/tokens/instance/overview_view.ex

@@ -1,8 +1,8 @@
 defmodule BlockScoutWeb.Tokens.Instance.OverviewView do
   use BlockScoutWeb, :view
 
-  alias Explorer.Chain.Token
   alias BlockScoutWeb.CurrencyHelpers
+  alias Explorer.Chain.{Address, SmartContract, Token}
 
   def token_name?(%Token{name: nil}), do: false
   def token_name?(%Token{name: _}), do: true
@@ -18,4 +18,12 @@ defmodule BlockScoutWeb.Tokens.Instance.OverviewView do
     price = token.usd_value
     Decimal.mult(tokens, price)
   end
+
+  def smart_contract_with_read_only_functions?(
+        %Token{contract_address: %Address{smart_contract: %SmartContract{}}} = token
+      ) do
+    Enum.any?(token.contract_address.smart_contract.abi, & &1["constant"])
+  end
+
+  def smart_contract_with_read_only_functions?(%Token{contract_address: %Address{smart_contract: nil}}), do: false
 end