Add timestamp function in smart contract library (#612)

* Add timestamp function in the SC library

* Add timestamp in the SC interpreter constants

* Add timestamp in the conditions

* Fix chain of SC

lib/archethic/contracts/contract/conditions.ex

@@ -12,6 +12,7 @@ defmodule Archethic.Contracts.Contract.Conditions do
     :uco_transfers,
     :token_transfers,
     :previous_public_key,
+    :timestamp,
     origin_family: :all
   ]
 
@@ -27,7 +28,8 @@ defmodule Archethic.Contracts.Contract.Conditions do
           uco_transfers: map() | Macro.t() | nil,
           token_transfers: map() | Macro.t() | nil,
           previous_public_key: binary() | Macro.t() | nil,
-          origin_family: SharedSecrets.origin_family() | :all
+          origin_family: SharedSecrets.origin_family() | :all,
+          timestamp: DateTime.t() | nil
         }
 
   def empty?(%__MODULE__{
@@ -38,7 +40,8 @@ defmodule Archethic.Contracts.Contract.Conditions do
         secrets: nil,
         uco_transfers: nil,
         token_transfers: nil,
-        previous_public_key: nil
+        previous_public_key: nil,
+        timestamp: nil
       }),
       do: true
 

lib/archethic/contracts/contract/constants.ex

@@ -18,6 +18,7 @@ defmodule Archethic.Contracts.Contract.Constants do
   alias Archethic.TransactionChain.TransactionData.Ownership
   alias Archethic.TransactionChain.TransactionData.UCOLedger
   alias Archethic.TransactionChain.TransactionData.UCOLedger.Transfer, as: UCOTransfer
+  alias Archethic.TransactionChain.Transaction.ValidationStamp
 
   @doc """
   Extract constants from a transaction into a map
@@ -40,7 +41,8 @@ defmodule Archethic.Contracts.Contract.Constants do
             }
           },
           recipients: recipients
-        }
+        },
+        validation_stamp: validation_stamp
       }) do
     %{
       "address" => address,
@@ -75,7 +77,16 @@ defmodule Archethic.Contracts.Contract.Constants do
           }
 
           Map.update(acc, to, [token_transfer], &[token_transfer | &1])
-        end)
+        end),
+      "timestamp" =>
+        case validation_stamp do
+          # Happens during the transaction validation
+          nil ->
+            nil
+
+          %ValidationStamp{timestamp: timestamp} ->
+            DateTime.to_unix(timestamp)
+        end
     }
   end
 

lib/archethic/contracts/interpreter.ex

@@ -596,6 +596,11 @@ defmodule Archethic.Contracts.Interpreter do
     {node, acc}
   end
 
+  # Whitelist the timestamp/0 function
+  defp prewalk(node = {{:atom, "timestamp"}, _, []}, acc = {:ok, %{scope: scope}})
+       when scope != :root,
+       do: {node, acc}
+
   defp prewalk(
          node = {{:atom, "get_genesis_public_key"}, _, [_address]},
          acc = {:ok, %{scope: scope}}
@@ -664,6 +669,10 @@ defmodule Archethic.Contracts.Interpreter do
     {node, acc}
   end
 
+  # Whitelist the timestamp/0 function in condition
+  defp prewalk(node = {{:atom, "timestamp"}, _, []}, acc = {:ok, %{scope: :condition}}),
+    do: {node, acc}
+
   # Whitelist the used of functions in the actions
   defp prewalk(node = {{:atom, fun_name}, _, _}, {:ok, acc = %{scope: :actions}})
        when fun_name in @transaction_statements_functions_names,
@@ -1436,6 +1445,21 @@ defmodule Archethic.Contracts.Interpreter do
     {:previous_public_key, true}
   end
 
+  defp validate_condition({:timestamp, nil}, _) do
+    # Skip the verification as timestamp change for each transaction
+    {:timestamp, true}
+  end
+
+  defp validate_condition({:type, nil}, %{"next" => %{"type" => "transfer"}}) do
+    # Skip the verification when it's the default type
+    {:type, true}
+  end
+
+  defp validate_condition({:content, nil}, %{"next" => %{"content" => ""}}) do
+    # Skip the verification when it's the default type
+    {:content, true}
+  end
+
   # Validation rules for inherit constraints
   defp validate_condition({field, nil}, %{"previous" => prev, "next" => next}) do
     {field, Map.get(prev, Atom.to_string(field)) == Map.get(next, Atom.to_string(field))}

lib/archethic/contracts/interpreter/library.ex

@@ -196,4 +196,10 @@ defmodule Archethic.Contracts.Interpreter.Library do
   end
 
   defp download_first_address([], _address), do: {:error, :network_issue}
+
+  @doc """
+  Return the current UNIX timestamp
+  """
+  @spec timestamp() :: non_neg_integer()
+  def timestamp, do: DateTime.utc_now() |> DateTime.to_unix()
 end

lib/archethic/contracts/worker.ex

@@ -335,7 +335,6 @@ defmodule Archethic.Contracts.Worker do
       %{next_transaction: next_tx, previous_transaction: prev_tx}
       |> chain_type()
       |> chain_code()
-      |> chain_content()
       |> chain_ownerships()
 
     case get_transaction_seed(prev_tx) do
@@ -379,10 +378,10 @@ defmodule Archethic.Contracts.Worker do
   defp chain_type(
          acc = %{
            next_transaction: %Transaction{type: nil},
-           previous_transaction: %Transaction{type: previous_type}
+           previous_transaction: _
          }
        ) do
-    put_in(acc, [:next_transaction, :type], previous_type)
+    put_in(acc, [:next_transaction, Access.key(:type)], :transfer)
   end
 
   defp chain_type(acc), do: acc
@@ -398,21 +397,6 @@ defmodule Archethic.Contracts.Worker do
 
   defp chain_code(acc), do: acc
 
-  defp chain_content(
-         acc = %{
-           next_transaction: %Transaction{data: %TransactionData{content: ""}},
-           previous_transaction: %Transaction{data: %TransactionData{content: previous_content}}
-         }
-       ) do
-    put_in(
-      acc,
-      [:next_transaction, Access.key(:data, %{}), Access.key(:content)],
-      previous_content
-    )
-  end
-
-  defp chain_content(acc), do: acc
-
   defp chain_ownerships(
          acc = %{
            next_transaction: %Transaction{data: %TransactionData{ownerships: []}},

test/archethic/contracts/worker_test.exs

@@ -27,6 +27,7 @@ defmodule Archethic.Contracts.WorkerTest do
   alias Archethic.TransactionChain.TransactionData.UCOLedger.Transfer
   alias Archethic.TransactionChain.TransactionData.TokenLedger
   alias Archethic.TransactionChain.TransactionData.TokenLedger.Transfer, as: TokenTransfer
+  alias Archethic.TransactionChain.Transaction.ValidationStamp
   alias Archethic.TransactionChain.Transaction.ValidationStamp.LedgerOperations.UnspentOutput
 
   alias Archethic.PubSub
@@ -80,7 +81,8 @@ defmodule Archethic.Contracts.WorkerTest do
         previous_public_key:
           transaction_seed
           |> Crypto.derive_keypair(0)
-          |> elem(0)
+          |> elem(0),
+        validation_stamp: %ValidationStamp{timestamp: DateTime.utc_now()}
       }
       |> Constants.from_transaction()
 
@@ -255,7 +257,8 @@ defmodule Archethic.Contracts.WorkerTest do
       assert :ok =
                Worker.execute(contract_address, %Transaction{
                  address: "@Bob3",
-                 data: %TransactionData{}
+                 data: %TransactionData{},
+                 validation_stamp: %ValidationStamp{timestamp: DateTime.utc_now()}
                })
 
       receive do
@@ -301,7 +304,8 @@ defmodule Archethic.Contracts.WorkerTest do
       assert :ok =
                Worker.execute(contract_address, %Transaction{
                  address: "@Bob3",
-                 data: %TransactionData{content: "Mr.X"}
+                 data: %TransactionData{content: "Mr.X"},
+                 validation_stamp: %ValidationStamp{timestamp: DateTime.utc_now()}
                })
 
       receive do
@@ -317,7 +321,8 @@ defmodule Archethic.Contracts.WorkerTest do
       assert {:error, :invalid_condition} =
                Worker.execute(contract_address, %Transaction{
                  address: "@Bob3",
-                 data: %TransactionData{content: "Mr.Z"}
+                 data: %TransactionData{content: "Mr.Z"},
+                 validation_stamp: %ValidationStamp{timestamp: DateTime.utc_now()}
                })
 
       refute_receive {:transaction_sent, _}
@@ -367,7 +372,8 @@ defmodule Archethic.Contracts.WorkerTest do
       assert :ok =
                Worker.execute(contract_address, %Transaction{
                  address: "@Bob3",
-                 data: %TransactionData{content: "Mr.X"}
+                 data: %TransactionData{content: "Mr.X"},
+                 validation_stamp: %ValidationStamp{timestamp: DateTime.utc_now()}
                })
 
       receive do
@@ -428,7 +434,8 @@ defmodule Archethic.Contracts.WorkerTest do
         type: :oracle,
         data: %TransactionData{
           content: Jason.encode!(%{"uco" => %{"eur" => 0.21}})
-        }
+        },
+        validation_stamp: %ValidationStamp{timestamp: DateTime.utc_now()}
       }
 
       PubSub.notify_new_transaction("@Oracle1", :oracle, DateTime.utc_now())
@@ -500,7 +507,8 @@ defmodule Archethic.Contracts.WorkerTest do
                      }
                    },
                    recipients: [contract_address]
-                 }
+                 },
+                 validation_stamp: %ValidationStamp{timestamp: DateTime.utc_now()}
                })
 
       receive do