defmodule ISO8583 do
  @moduledoc ~S"""
  ISO 8583 messaging library for Elixir. This library has utilities validate, encode and decode message 
  between systems using ISO 8583 regadless of the language the other system is written in.

    ```elixir
      message = %{ "0": "0800",  "11": "646465", "12": "160244", "13": "0818", "7": "0818160244","70": "001"}
      {:ok, encoded} = ISO8583.encode(message)
      # {:ok, <<0, 49, 48, 56, 48, 48, 130, 56, 0, 0, 0, 0, 0, 0, 4, 0, 0, 0, 0, 0, 0, 0, 48, 49, 56, 49, 54, ...>>}
      {:ok, decoded} = ISO8583.decode(encoded)
      # {:ok, %{ "0": "0800",  "11": "646465", "12": "160244", "13": "0818", "7": "0818160244","70": "001"}}
    ```

  ## Installation

    ```elixir
    def deps do
      [
        {:iso_8583, "~> 0.1.2"}
      ]
    end
    ```
  ## Customization and configuration

    All exposed API functions take options with the following configurable options.
    
    ### TCP Length Indicator
    This is used to specify whether or not to include the 2 byte hexadecimal encoded byte length of the whole message
    whe encoding or to consider it when decoding.
    This value is set to true by default.
    Example:
    ```elixir
    ISO8583.encode(some_message, tcp_len_header: false)
    ```

  ### Bitmap encoding

    Primary and SecondaryBitmap encoding bitmap for fields 0-127 is configurable like below.

    Examples:

    ```elixir
    ISO8583.encode(some_message, bitmap_encoding: :ascii) # will result in 32 byte length bitmap
    ```

    ```elixir
    ISO8583.encode(some_message) # will default to :hex result in 16 byte length bitmap encoded hexadecimal
    ```

  ### Custom formats

    Custom formats for data type, data length and length type for all fields including special bitmaps like 
    for 127.1 and 127.25.1 are configurable through custom formats. The default formats will be replaced by the custom one.

    To see the default formats [check here](https://github.com/zemuldo/iso_8583_elixir/blob/master/lib/iso_8583/formats/formats.ex#L104)

    Example:

    Here we override field 2 to have maximum of 30 characters.

    ```elixir
     custome_format = %{
          "2": %{
            content_type: "n",
            label: "Primary account number (PAN)",
            len_type: "llvar",
            max_len: 30,
            min_len: 1
          }
        }

     message = some_message |> Map.put(:"2", "444466668888888888888888")

     ISO8583.encode(message, formats: custome_format)
    ```
  ### Custom Static Metadata
    There is an option to configure static metadata to an iso message. 
    Static metadata are info in like text format encoded at special locations in the message usually at the beginning
    of the message and agreed upon by the sender and receiver.
    This library considers the static metadata just after the MTI.
  """

  import ISO8583.Encode
  alias ISO8583.DataTypes
  import ISO8583.Decode
  alias ISO8583.Formats
  alias ISO8583.Message.ResponseStatus
  alias ISO8583.Utils

  @doc """
  Function to encode json or Elixir map into ISO 8583 encoded binary. Use this to encode all fields that are supported.
  See the formats module for details.
  ## Examples
      iex> message = %{
      iex>   "0": "0800",
      iex>   "7": "0818160244",
      iex>   "11": "646465",
      iex>   "12": "160244",
      iex>   "13": "0818",
      iex>   "70": "001"
      iex> }
      %{
      "0": "0800",
      "11": "646465",
      "12": "160244",
      "13": "0818",
      "7": "0818160244",
      "70": "001"
      }
      iex>ISO8583.encode(message)
      {:ok, <<0, 49, 48, 56, 48, 48, 130, 56, 0, 0, 0, 0, 
      0, 0, 4, 0, 0, 0, 0, 0, 0, 0, 48, 56, 49, 56, 
      49, 54, 48, 50, 52, 52, 54, 52, 54, 52, 54, 53, 
      49, 54, 48, 50, 52, 52, 48, 56, 49, 56, 48, 48, 
      49>>}
  """

  @spec encode(message :: map(), opts :: Keyword.t()) :: {:ok, binary()} | {:error, String.t()}
  def encode(message, opts \\ [])

  def encode(message, opts) do
    opts = opts |> default_opts()

    message
    |> Utils.atomify_map()
    |> encode_0_127(opts)
  end

  @doc """
  Function to encode field 127 extensions.
  ## Examples

      iex>message = %{
      iex>"127.1": "0000008000000000",
      iex>"127.25": "7E1E5F7C0000000000000000500000000000000014A00000000310105C000128FF0061F379D43D5AEEBC8002800000000000000001E0302031F000203001406010A03A09000008CE0D0C840421028004880040417091180000014760BAC24959"
      iex>}
      %{
        "127.1": "0000008000000000",
        "127.25": "7E1E5F7C0000000000000000500000000000000014A00000000310105C000128FF0061F379D43D5AEEBC8002800000000000000001E0302031F000203001406010A03A09000008CE0D0C840421028004880040417091180000014760BAC24959"
      }
      iex>ISO8583.encode_127(message)
      {:ok, %{
        "127": "000000800000000001927E1E5F7C0000000000000000500000000000000014A00000000310105C000128FF0061F379D43D5AEEBC8002800000000000000001E0302031F000203001406010A03A09000008CE0D0C840421028004880040417091180000014760BAC24959", 
        "127.1": "0000008000000000", 
        "127.25": "7E1E5F7C0000000000000000500000000000000014A00000000310105C000128FF0061F379D43D5AEEBC8002800000000000000001E0302031F000203001406010A03A09000008CE0D0C840421028004880040417091180000014760BAC24959"
      }}
  """

  @spec encode_127(message :: map(), opts :: Keyword.t()) ::
          {:ok, binary()} | {:error, String.t()}
  def encode_127(message, opts \\ []) do
    opts = opts |> default_opts()

    message
    |> encoding_extensions(:"127", opts)
  end

  @doc """
  Function to encode field 127.25 extensions.
  ## Examples

      iex>message = %{
      iex>"127.25.1": "7E1E5F7C00000000",
      iex>"127.25.12": "61F379D43D5AEEBC",
      iex>"127.25.13": "80",
      iex>"127.25.14": "00000000000000001E0302031F00",
      iex>"127.25.15": "020300",
      iex>"127.25.18": "06010A03A09000",
      iex>"127.25.2": "000000005000",
      iex>"127.25.20": "008C",
      iex>"127.25.21": "E0D0C8",
      iex>"127.25.22": "404",
      iex>"127.25.23": "21",
      iex>"127.25.24": "0280048800",
      iex>"127.25.26": "404",
      iex>"127.25.27": "170911",
      iex>"127.25.28": "00000147",
      iex>"127.25.29": "60",
      iex>"127.25.3": "000000000000",
      iex>"127.25.30": "BAC24959",
      iex>"127.25.4": "A0000000031010",
      iex>"127.25.5": "5C00",
      iex>"127.25.6": "0128",
      iex>"127.25.7": "FF00"
      iex>}
      %{
        "127.25.1": "7E1E5F7C00000000",
        "127.25.2": "000000005000",
        "127.25.3": "000000000000",
        "127.25.4": "A0000000031010",
        "127.25.5": "5C00",
        "127.25.6": "0128",
        "127.25.7": "FF00",
        "127.25.12": "61F379D43D5AEEBC",
        "127.25.13": "80",
        "127.25.14": "00000000000000001E0302031F00",
        "127.25.15": "020300",
        "127.25.18": "06010A03A09000",
        "127.25.20": "008C",
        "127.25.21": "E0D0C8",
        "127.25.22": "404",
        "127.25.23": "21",
        "127.25.24": "0280048800",
        "127.25.26": "404",
        "127.25.27": "170911",
        "127.25.28": "00000147",
        "127.25.29": "60",
        "127.25.30": "BAC24959"
      }
      iex>ISO8583.encode_127_25(message)
      {:ok, %{
        "127.25": "01927E1E5F7C0000000000000000500000000000000014A00000000310105C000128FF0061F379D43D5AEEBC8002800000000000000001E0302031F000203001406010A03A09000008CE0D0C840421028004880040417091180000014760BAC24959", 
        "127.25.1": "7E1E5F7C00000000", 
        "127.25.12": "61F379D43D5AEEBC", 
        "127.25.13": "80", 
        "127.25.14": "00000000000000001E0302031F00", 
        "127.25.15": "020300", 
        "127.25.18": "06010A03A09000", 
        "127.25.2": "000000005000", 
        "127.25.20": "008C", 
        "127.25.21": "E0D0C8", 
        "127.25.22": "404", 
        "127.25.23": "21", 
        "127.25.24": "0280048800", 
        "127.25.26": "404", 
        "127.25.27": "170911", 
        "127.25.28": "00000147", 
        "127.25.29": "60", 
        "127.25.3": "000000000000", 
        "127.25.30": "BAC24959", 
        "127.25.4": "A0000000031010", 
        "127.25.5": "5C00", 
        "127.25.6": "0128", 
        "127.25.7": "FF00"
      }}
  """

  @spec encode_127_25(message :: map(), opts :: Keyword.t()) ::
          {:ok, binary()} | {:error, String.t()}
  def encode_127_25(message, opts \\ []) do
    opts = opts |> default_opts()

    message
    |> encoding_extensions(:"127.25", opts)
  end

  @doc """
  Function to decode an ISO8583 binary using custimizable rules as describe in customization section.
  See the formats module for details.
  ## Examples
      iex> message = <<0, 49, 48, 56, 48, 48, 130, 56, 0, 0, 0, 0,
      iex> 0, 0, 4, 0, 0, 0, 0, 0, 0, 0, 48, 56, 49, 56, 
      iex> 49, 54, 48, 50, 52, 52, 54, 52, 54, 52, 54, 53,
      iex> 49, 54, 48, 50, 52, 52, 48, 56, 49, 56, 48, 48, 
      iex> 49>>
      iex>ISO8583.decode(message)
      {:ok, %{
      "0": "0800",
      "11": "646465",
      "12": "160244",
      "13": "0818",
      "7": "0818160244",
      "70": "001"
      }}
  """

  @spec decode(message :: binary(), opts :: Keyword.t()) :: {:ok, map()} | {:error, String.t()}
  def decode(message, opts \\ []) do
    opts = opts |> default_opts()

    message
    |> decode_0_127(opts)
  end

  @doc """
  Function to expand field 127 to its sub fields.
  ## Examples

      iex>message = %{
      iex>"127": "000000800000000001927E1E5F7C0000000000000000500000000000000014A00000000310105C000128FF0061F379D43D5AEEBC8002800000000000000001E0302031F000203001406010A03A09000008CE0D0C840421028004880040417091180000014760BAC24959"
      iex>}
      %{
          "127": "000000800000000001927E1E5F7C0000000000000000500000000000000014A00000000310105C000128FF0061F379D43D5AEEBC8002800000000000000001E0302031F000203001406010A03A09000008CE0D0C840421028004880040417091180000014760BAC24959"
      }
      iex>ISO8583.decode_127(message)
      {:ok, %{
          "127": "000000800000000001927E1E5F7C0000000000000000500000000000000014A00000000310105C000128FF0061F379D43D5AEEBC8002800000000000000001E0302031F000203001406010A03A09000008CE0D0C840421028004880040417091180000014760BAC24959",
          "127.25": "7E1E5F7C0000000000000000500000000000000014A00000000310105C000128FF0061F379D43D5AEEBC8002800000000000000001E0302031F000203001406010A03A09000008CE0D0C840421028004880040417091180000014760BAC24959"
       }}
  """

  @spec decode_127(message :: binary(), opts :: Keyword.t()) ::
          {:ok, map()} | {:error, String.t()}
  def decode_127(message, opts \\ [])

  def decode_127(message, opts) when is_binary(message) do
    opts = opts |> default_opts()

    message
    |> expand_field("127.", opts)
  end

  def decode_127(message, opts) do
    opts = opts |> default_opts()

    message
    |> expand_field("127.", opts)
  end

  @doc """
  Function to expand field 127.25 to its sub fields
  ## Examples

      iex>message = %{
      iex>"127": "000000800000000001927E1E5F7C0000000000000000500000000000000014A00000000310105C000128FF0061F379D43D5AEEBC8002800000000000000001E0302031F000203001406010A03A09000008CE0D0C840421028004880040417091180000014760BAC24959",
      iex>"127.25": "7E1E5F7C0000000000000000500000000000000014A00000000310105C000128FF0061F379D43D5AEEBC8002800000000000000001E0302031F000203001406010A03A09000008CE0D0C840421028004880040417091180000014760BAC24959"
      iex>}
      %{
          "127": "000000800000000001927E1E5F7C0000000000000000500000000000000014A00000000310105C000128FF0061F379D43D5AEEBC8002800000000000000001E0302031F000203001406010A03A09000008CE0D0C840421028004880040417091180000014760BAC24959",
          "127.25": "7E1E5F7C0000000000000000500000000000000014A00000000310105C000128FF0061F379D43D5AEEBC8002800000000000000001E0302031F000203001406010A03A09000008CE0D0C840421028004880040417091180000014760BAC24959"
      }
      iex>ISO8583.decode_127_25(message)
      {:ok, %{
        "127": "000000800000000001927E1E5F7C0000000000000000500000000000000014A00000000310105C000128FF0061F379D43D5AEEBC8002800000000000000001E0302031F000203001406010A03A09000008CE0D0C840421028004880040417091180000014760BAC24959",
        "127.25": "7E1E5F7C0000000000000000500000000000000014A00000000310105C000128FF0061F379D43D5AEEBC8002800000000000000001E0302031F000203001406010A03A09000008CE0D0C840421028004880040417091180000014760BAC24959",
        "127.25.12": "61F379D43D5AEEBC",
        "127.25.13": "80",
        "127.25.14": "00000000000000001E0302031F00",
        "127.25.15": "020300",
        "127.25.18": "06010A03A09000",
        "127.25.2": "000000005000",
        "127.25.20": "008C",
        "127.25.21": "E0D0C8",
        "127.25.22": "404",
        "127.25.23": "21",
        "127.25.24": "0280048800",
        "127.25.26": "404",
        "127.25.27": "170911",
        "127.25.28": "00000147",
        "127.25.29": "60",
        "127.25.3": "000000000000",
        "127.25.30": "BAC24959",
        "127.25.4": "A0000000031010",
        "127.25.5": "5C00",
        "127.25.6": "0128",
        "127.25.7": "FF00"
      }}
  """

  @spec decode_127_25(message :: binary(), opts :: Keyword.t()) ::
          {:ok, map()} | {:error, String.t()}
  def decode_127_25(message, opts \\ []) do
    opts = opts |> default_opts()

    message
    |> expand_field("127.25.", opts)
  end

  @doc """
  Function check if json message is valid.
  ## Examples
      iex> message = %{
      iex>   "0": "0800",
      iex>   "7": "0818160244",
      iex>   "11": "646465",
      iex>   "12": "160244",
      iex>   "13": "0818",
      iex>   "70": "001"
      iex> }
      %{
      "0": "0800",
      "11": "646465",
      "12": "160244",
      "13": "0818",
      "7": "0818160244",
      "70": "001"
      }
      iex>ISO8583.valid?(message)
      true
      iex> message = <<0, 49, 48, 56, 48, 48, 130, 56, 0, 0, 0, 0,
      iex> 0, 0, 4, 0, 0, 0, 0, 0, 0, 0, 48, 56, 49, 56, 
      iex> 49, 54, 48, 50, 52, 52, 54, 52, 54, 52, 54, 53,
      iex> 49, 54, 48, 50, 52, 52, 48, 56, 49, 56, 48, 48, 
      iex> 49>>
      iex>ISO8583.valid?(message)
      true
  """

  @spec valid?(message :: binary() | map(), opts :: Keyword.t()) :: true | false
  def valid?(message, opts \\ [])

  def valid?(message, opts) when is_map(message) do
    opts = opts |> default_opts()

    with atomified <- Utils.atomify_map(message),
         {:ok, _} <- DataTypes.valid?(atomified, opts) do
      true
    else
      _ -> false
    end
  end

  def valid?(message, opts) when is_binary(message) do
    opts = opts |> default_opts()

    case decode(message, opts) do
      {:ok, _} -> true
      {:error, _} -> false
    end
  end

  @doc """
  Function check if json message is valid.
  ## Examples
      iex> message = %{
      iex>   "0": "0800",
      iex>   "7": "0818160244",
      iex>   "11": "646465",
      iex>   "12": "160244",
      iex>   "13": "0818",
      iex>   "70": "001"
      iex> }
      %{
      "0": "0800",
      "11": "646465",
      "12": "160244",
      "13": "0818",
      "7": "0818160244",
      "70": "001"
      }
      iex>ISO8583.valid(message)
      {:ok, message}
      iex> message = <<0, 49, 48, 56, 48, 48, 130, 56, 0, 0, 0, 0,
      iex> 0, 0, 4, 0, 0, 0, 0, 0, 0, 0, 48, 56, 49, 56, 
      iex> 49, 54, 48, 50, 52, 52, 54, 52, 54, 52, 54, 53,
      iex> 49, 54, 48, 50, 52, 52, 48, 56, 49, 56, 48, 48, 
      iex> 49>>
      iex>ISO8583.valid(message)
      {:ok, %{
      "0": "0800",
      "11": "646465",
      "12": "160244",
      "13": "0818",
      "7": "0818160244",
      "70": "001"
      }}
  """
  @spec valid(message :: map() | binary(), opts :: Keyword.t()) ::
          {:ok, map()} | {:error, String.t()}
  def valid(message, opts \\ [])

  def valid(message, opts) when is_map(message) do
    opts = opts |> default_opts()

    message
    |> Utils.atomify_map()
    |> DataTypes.valid?(opts)
  end

  def valid(message, opts) when is_binary(message) do
    opts = opts |> default_opts()

    message |> decode(opts)
  end

  defp default_opts([]) do
    [bitmap_encoding: :hex, tcp_len_header: true, formats: Formats.formats_definitions()]
  end

  defp default_opts(opts) do
    default_opts([])
    |> Keyword.merge(opts)
    |> configure_formats()
  end

  defp configure_formats(opts) do
    case opts[:formats] |> is_map() do
      false ->
        opts
        |> Keyword.put(:formats, Formats.formats_definitions())

      true ->
        formats_with_customs =
          Formats.formats_definitions()
          |> Map.merge(opts[:formats] |> Utils.atomify_map())

        opts
        |> Keyword.merge(formats: formats_with_customs)
    end
  end

  @doc """
  Fucntion to get the message status.
  ## Examples

      iex> ISO8583.status(%{"0": "0110", "39": "00"})
      {:ok, "Approved or completed successfully"}
      iex> ISO8583.status(%{"0": "0110", "39": "01"})
      {:error, "Refer to card issuer"}
      iex> ISO8583.status(%{"0": "0110", "39": "000"})
      {:error, "Unknown statuscode"}
  """
  @spec status(message: map()) :: {:ok, String.t()} | {:error, String.t()}
  def status(message) when is_map(message) do
    message
    |> ResponseStatus.ok?()
  end

  def status(_), do: {:error, "Message has to be a map with field 39"}
end