defmodule Forge do
  @moduledoc """
  Public interfaces for using Forge
  """
  defmodule Handler do
    @moduledoc """
    Forge handler behavior
    """
    alias Forge.{Account, AccountState, Context, HandlerResponse, TransactionMessage}
    alias Google.Protobuf.Any

    @callback verify(TransactionMessage.t(), Account.t(), AccountState.t()) :: true | false
    @callback update_state(String.t(), Any.t(), Account.t(), Context.t()) :: HandlerResponse.t()
  end

  defmodule Context do
    @moduledoc false

    @typedoc """
    The context passed into the application handler by forge. It contains keys as folows:

    * `:tx_hash`: the hash of the transaction that being handled. Application can record this in their state as a reference.
    * `:block_height`: the height of the current block.
    * `:block_time`: the deterministic time (in google protobuf timestamp format) of the current block.
    * `:address`: the self address of the state.
    * `:owner`: the owner address of the state, if any.
    """
    @type t :: %__MODULE__{
            tx_hash: String.t(),
            block_height: non_neg_integer(),
            block_time: Google.Protobuf.Timestamp.t(),
            address: String.t(),
            owner: String.t()
          }
    defstruct [:tx_hash, :block_height, :block_time, :address, :owner]
  end

  defmodule HandlerResponse do
    @moduledoc false

    alias Forge.Account

    @typedoc """
    The response from handler. It contains keys as follows:

    * `:trie`: the account state db
    * `:data`: the data returned by the handler to put into tendermint transaction
    * `:info`: the info returned by the handler to put into tendermint transaction
    * `:log`: the log returned by the handler to put into tendermint transaction
    * `:gas_wanted`: the gas wanted by the handler
    * `:gas_used`: the gas used by the handler
    * `:tags`: the tags returned by the handler, for indexing purpose
    """
    @type t :: %__MODULE__{
            trie: Account.t(),
            data: String.t(),
            info: String.t(),
            log: String.t(),
            gas_wanted: non_neg_integer(),
            gas_used: non_neg_integer(),
            tags: [String.t()]
          }
    defstruct trie: nil, data: "", info: "", log: "", gas_wanted: 0, gas_used: 0, tags: []

    def new(attrs) do
      struct(%__MODULE__{}, attrs)
    end
  end
end