Add fn in SC lib to get genesis address in smart contract

lib/archethic/contracts/interpreter.ex

@@ -587,6 +587,14 @@ defmodule ArchEthic.Contracts.Interpreter do
        when scope != :root,
        do: {node, acc}
 
+  # Whitelist the get_genesis_address/1 function in condition
+  defp prewalk(
+         node = {{:atom, "get_genesis_address"}, _, [_address]},
+         acc = {:ok, %{scope: :condition}}
+       ) do
+    {node, acc}
+  end
+
   # Whitelist the regex_match?/1 function in the condition
   defp prewalk(
          node = {{:atom, "regex_match?"}, _, [_search]},
@@ -631,6 +639,14 @@ defmodule ArchEthic.Contracts.Interpreter do
   defp prewalk(node = {{:atom, "size"}, _, []}, acc = {:ok, %{scope: :condition}}),
     do: {node, acc}
 
+  # Whitelist the get_genesis_address/1 function in actions
+  defp prewalk(
+         node = {{:atom, "get_genesis_address"}, _, [_address]},
+         acc = {:ok, %{scope: :actions}}
+       ) do
+    {node, acc}
+  end
+
   # 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,

lib/archethic/contracts/interpreter/library.ex

@@ -2,6 +2,10 @@ defmodule ArchEthic.Contracts.Interpreter.Library do
   @moduledoc false
 
   alias ArchEthic.Crypto
+  alias ArchEthic.P2P
+  alias ArchEthic.P2P.Message.GetFirstAddress
+  alias ArchEthic.P2P.Message.FirstAddress
+  alias ArchEthic.Election
 
   @doc """
   Match a regex expression
@@ -79,12 +83,12 @@ defmodule ArchEthic.Contracts.Interpreter.Library do
   end
 
   @doc ~S"""
-  Match a json path expression 
+  Match a json path expression
 
   ## Examples
 
        iex> Library.json_path_match?("{\"1622541930\":{\"uco\":{\"eur\":0.176922,\"usd\":0.21642}}}", "$.*.uco.usd")
-       true     
+       true
   """
   @spec json_path_match?(binary(), binary()) :: boolean()
   def json_path_match?(text, path) when is_binary(text) and is_binary(path) do
@@ -149,4 +153,26 @@ defmodule ArchEthic.Contracts.Interpreter.Library do
   def size(binary) when is_binary(binary), do: byte_size(binary)
   def size(list) when is_list(list), do: length(list)
   def size(map) when is_map(map), do: map_size(map)
+
+  @doc """
+  Get the genesis address of the chain
+
+  """
+  @spec get_genesis_address(binary()) ::
+          binary()
+  def get_genesis_address(address) do
+    address = Base.decode16!(address)
+    nodes = Election.chain_storage_nodes(address, P2P.available_nodes())
+    {:ok, address} = download_first_address(nodes, address)
+    address
+  end
+
+  defp download_first_address([node | rest], address) do
+    case P2P.send_message(node, %GetFirstAddress{address: address}) do
+      {:ok, %FirstAddress{address: address}} -> {:ok, address}
+      {:error, _} -> download_first_address(rest, address)
+    end
+  end
+
+  defp download_first_address([], _address), do: {:error, :network_issue}
 end

lib/archethic/p2p/message.ex

@@ -27,6 +27,8 @@ defmodule ArchEthic.P2P.Message do
   alias __MODULE__.EncryptedStorageNonce
   alias __MODULE__.Error
   alias __MODULE__.FirstPublicKey
+  alias __MODULE__.FirstAddress
+  alias __MODULE__.GetFirstAddress
   alias __MODULE__.GetBalance
   alias __MODULE__.GetBeaconSummaries
   alias __MODULE__.GetBeaconSummary
@@ -114,6 +116,7 @@ defmodule ArchEthic.P2P.Message do
           | BeaconUpdate.t()
           | TransactionSummary.t()
           | ReplicationAttestation.t()
+          | GetFirstAddress.t()
 
   @type response ::
           Ok.t()
@@ -135,6 +138,7 @@ defmodule ArchEthic.P2P.Message do
           | Error.t()
           | Summary.t()
           | BeaconSummaryList.t()
+          | FirstAddress.t()
 
   @doc """
   Extract the Message Struct name
@@ -332,6 +336,14 @@ defmodule ArchEthic.P2P.Message do
     <<30::8, ReplicationAttestation.serialize(attestation)::binary>>
   end
 
+  def encode(%GetFirstAddress{address: address}) do
+    <<31::8, address::binary>>
+  end
+
+  def encode(%FirstAddress{address: address}) do
+    <<235::8, address::binary>>
+  end
+
   def encode(%BeaconUpdate{transaction_attestations: transaction_attestations}) do
     transaction_attestations_bin =
       transaction_attestations
@@ -740,6 +752,16 @@ defmodule ArchEthic.P2P.Message do
     ReplicationAttestation.deserialize(rest)
   end
 
+  def decode(<<31::8, rest::bitstring>>) do
+    {address, rest} = Utils.deserialize_address(rest)
+    {%GetFirstAddress{address: address}, rest}
+  end
+
+  def decode(<<235::8, rest::bitstring>>) do
+    {address, rest} = Utils.deserialize_address(rest)
+    {%FirstAddress{address: address}, rest}
+  end
+
   def decode(<<236::8, nb_transaction_attestations::16, rest::bitstring>>) do
     {transaction_attestations, rest} =
       Utils.deserialize_transaction_attestations(rest, nb_transaction_attestations, [])
@@ -1176,6 +1198,16 @@ defmodule ArchEthic.P2P.Message do
     end
   end
 
+  def process(%GetFirstAddress{address: address}) do
+    case TransactionChain.get_first_transaction(address, [:address]) do
+      {:ok, %Transaction{address: address}} ->
+        %FirstAddress{address: address}
+
+      {:error, :transaction_not_exits} ->
+        %NotFound{}
+    end
+  end
+
   def process(%GetLastTransactionAddress{address: address, timestamp: timestamp}) do
     address = TransactionChain.get_last_address(address, timestamp)
     %LastTransactionAddress{address: address}

lib/archethic/p2p/message/first_address.ex

@@ -0,0 +1,11 @@
+defmodule ArchEthic.P2P.Message.FirstAddress do
+  @moduledoc """
+  Represents a message to first address from the transaction chain
+  """
+  @enforce_keys [:address]
+  defstruct [:address]
+
+  @type t :: %__MODULE__{
+          address: binary()
+        }
+end

lib/archethic/p2p/message/get_first_address.ex

@@ -0,0 +1,12 @@
+defmodule ArchEthic.P2P.Message.GetFirstAddress do
+  @moduledoc """
+  Represents a message to request the first address from a transaction chain
+  """
+
+  @enforce_keys [:address]
+  defstruct [:address]
+
+  @type t() :: %__MODULE__{
+          address: binary()
+        }
+end

test/archethic/contracts/interpreter/library_test.exs

@@ -1,5 +1,5 @@
 defmodule ArchEthic.Contracts.Interpreter.LibraryTest do
-  use ExUnit.Case
+  use ArchEthicCase
 
   alias ArchEthic.Contracts.Interpreter.Library