defmodule ExCius do
  @moduledoc """
  ExCius - A library for creating and parsing UBL 2.1 invoices compliant with Croatian e-Invoice (CIUS-2025) specification.
  """

  alias ExCius.{RequestParams, InvoiceTemplateXML, InvoiceUtils}

  def generate_invoice(invoice_data) when is_map(invoice_data) do
    case RequestParams.new(invoice_data) do
      {:ok, validated_params} ->
        xml = InvoiceTemplateXML.build_xml(validated_params)
        {:ok, xml}

      {:error, errors} ->
        {:error, errors}
    end
  end

  def generate_invoice(_), do: {:error, %{input: "must be a map"}}

  def parse_invoice(xml) when is_binary(xml) do
    ExCius.InvoiceXmlParserFixed.parse(xml)
  end

  def parse_invoice(_), do: {:error, "Input must be an XML string"}

  def validate_invoice(invoice_data) when is_map(invoice_data) do
    RequestParams.new(invoice_data)
  end

  def validate_invoice(_), do: {:error, %{input: "must be a map"}}

  @doc """
  Checks if the given UBL Invoice XML is digitally signed.

  Returns `{:ok, true}` if the invoice contains a digital signature,
  `{:ok, false}` otherwise.

  ## Parameters

  - `xml` - UBL Invoice XML document as a string

  ## Examples

      iex> xml = File.read!("priv/examples/signed_with_pdf.xml")
      iex> ExCius.signed?(xml)
      {:ok, true}

  """
  def signed?(xml) when is_binary(xml) do
    InvoiceUtils.signed?(xml)
  end

  def signed?(_), do: {:error, "Input must be an XML string"}

  @doc """
  Checks if the given UBL Invoice XML is digitally signed.

  Returns `true` if signed, `false` otherwise. Raises on error.

  ## Parameters

  - `xml` - UBL Invoice XML document as a string

  ## Examples

      iex> xml = File.read!("priv/examples/signed_with_pdf.xml")
      iex> ExCius.signed!(xml)
      true

  """
  def signed!(xml) when is_binary(xml) do
    InvoiceUtils.signed!(xml)
  end

  @doc """
  Extracts all attachments from the given UBL Invoice XML.

  Returns a list of attachment maps containing:
  - `:id` - The document reference ID
  - `:type` - Either `:embedded` or `:external`
  - `:filename` - The filename (for embedded attachments)
  - `:mime_type` - The MIME type (for embedded attachments)
  - `:content` - The decoded binary content (for embedded attachments)
  - `:uri` - The external URI (for external references)

  ## Parameters

  - `xml` - UBL Invoice XML document as a string

  ## Examples

      iex> xml = File.read!("priv/examples/signed_with_pdf.xml")
      iex> {:ok, attachments} = ExCius.extract_attachments(xml)
      iex> length(attachments)
      1

  """
  def extract_attachments(xml) when is_binary(xml) do
    InvoiceUtils.extract_attachments(xml)
  end

  def extract_attachments(_), do: {:error, "Input must be an XML string"}

  @doc """
  Extracts all attachments from the given UBL Invoice XML.

  Returns a list of attachment maps. Raises on error.

  ## Parameters

  - `xml` - UBL Invoice XML document as a string

  ## Examples

      iex> xml = File.read!("priv/examples/signed_with_pdf.xml")
      iex> attachments = ExCius.extract_attachments!(xml)
      iex> length(attachments)
      1

  """
  def extract_attachments!(xml) when is_binary(xml) do
    InvoiceUtils.extract_attachments!(xml)
  end

  def round_trip_test(invoice_data) when is_map(invoice_data) do
    with {:ok, xml} <- generate_invoice(invoice_data),
         {:ok, parsed_data} <- parse_invoice(xml) do
      {:ok, {xml, parsed_data}}
    else
      error -> error
    end
  end

  def round_trip_test(_), do: {:error, "Input must be a map"}

  def version do
    case Application.spec(:ex_cius, :vsn) do
      nil -> "unknown"
      vsn -> List.to_string(vsn)
    end
  end

  def info do
    %{
      library_version: version(),
      ubl_version: "2.1",
      croatian_cius: "2025",
      supported_currencies: ["EUR"],
      mandatory_features: [
        "operator_notes",
        "croatian_date_format",
        "ubl_extensions",
        "party_tax_schemes"
      ],
      optional_features: [
        "payment_means",
        "due_dates",
        "contact_information",
        "commodity_classification",
        "user_notes"
      ]
    }
  end
end