defmodule Castile do
  @moduledoc """
  Documentation for Castile.
  """

  alias :erlsom, as: Erlsom

  @priv_dir Application.app_dir(:castile, "priv")

  defmodule Model do
    defstruct [:operations, :model]
  end

  def init_model(wsdl_file, prefix \\ 'p') do
    wsdl = Path.join([@priv_dir, "wsdl.xsd"])
    {:ok, wsdl_model} = Erlsom.compile_xsd_file(
      Path.join([@priv_dir, "soap.xsd"]),
      prefix: 'soap',
      include_files: [{'http://schemas.xmlsoap.org/wsdl/', 'wsdl', wsdl}]
    )
    # add the xsd model
    wsdl_model = Erlsom.add_xsd_model(wsdl_model)

    include_dir = Path.dirname(wsdl_file)
    options = [dir_list: include_dir]

    # parse wsdl
    {model, operations} = parse_wsdls([wsdl_file], prefix, wsdl_model, options, {nil, []})

    # TODO: add files as required
    # now compile envelope.xsd, and add Model
    {:ok, envelope_model} = Erlsom.compile_xsd_file(Path.join([@priv_dir, "envelope.xsd"]), prefix: 'soap')
    soap_model = Erlsom.add_model(envelope_model, model)
    # TODO: detergent enables you to pass some sort of AddFiles that will stitch together the soap model
    # SoapModel2 = addModels(AddFiles, SoapModel),

    %Model{operations: operations, model: soap_model}
  end

  def parse_wsdls([], _prefix, _wsdl_model, _opts, acc), do: acc

  def parse_wsdls([path | rest], prefix, wsdl_model, opts, {acc_model, acc_operations}) do
    {:ok, wsdl_file} = get_file(String.trim(path))
    {:ok, parsed, _} = Erlsom.scan(wsdl_file, wsdl_model)
    # get xsd elements from wsdl to compile
    xsds = extract_wsdl_xsds(parsed)
    # Now we need to build a list: [{Namespace, Prefix, Xsd}, ...] for all the Xsds in the WSDL.
    # This list is used when a schema inlcudes one of the other schemas. The AXIS java2wsdl
    # generates wsdls that depend on this feature.
    import_list = Enum.map(xsds, fn xsd ->
      {:erlsom_lib.getTargetNamespaceFromXsd(xsd), nil, xsd}
    end)

    # TODO: pass the right options here
    model = add_schemas(xsds, prefix, opts, import_list, acc_model)

    ports = get_ports(parsed)
    operations = get_operations(parsed, ports)
    imports = get_imports(parsed)

    acc = {model, operations ++ acc_operations}
    # process imports (recursively, so that imports in the imported files are
    # processed as well).
    # For the moment, the namespace is ignored on operations etc.
    # this makes it a bit easier to deal with imported wsdl's.
    acc = parse_wsdls(imports, prefix, wsdl_model, opts, acc)
    parse_wsdls(rest, prefix, wsdl_model, opts, acc)
  end

  # compile each of the schemas, and add it to the model.
  # Returns Model
  # (TODO: using the same prefix for all XSDS makes no sense, generate one)
  def add_schemas(xsds, prefix, opts, imports, acc_model \\ nil) do
    Enum.reduce(xsds, acc_model, fn xsd, acc ->
      case xsd do
        nil -> acc
        _ ->
          {:ok, model} = :erlsom_compile.compile_parsed_xsd(xsd, [{:prefix, prefix}, {:include_files, imports} | opts])

          case acc_model do
            nil -> model
            _ -> :erlsom.add_model(acc_model, model)
          end
      end
    end)
  end

  def get_file(uri) do
    case URI.parse(uri) do
      %{scheme: scheme} when scheme in ["http", "https"] ->
        raise "Not implemented"
        # get_remote_file()
      _ ->
        get_local_file(uri)
    end
  end

  def get_local_file(uri) do
    File.read(uri)
  end

  def extract_wsdl_xsds(wsdl) do
    case get_toplevel_elements(wsdl, :"wsdl:tTypes") do
      [{:"wsdl:tTypes", _attrs, _docs, choice}] -> choice
      [] -> []
    end
  end

  def get_toplevel_elements({:"wsdl:tDefinitions", _attrs, _namespace, _name, _docs, _any, choice}, type) do
    # TODO: reduce using function sigs instead
    Enum.reduce(choice, [], fn
      {:"wsdl:anyTopLevelOptionalElement", _attrs, tuple}, acc ->
        case elem(tuple, 0) do
          ^type -> [tuple | acc]
          _ -> acc
        end
      _, acc -> acc
    end)
  end

  # %% returns [#port{}]
  # %% -record(port, {service, port, binding, address}).

  #  TODO: use records everywhere
  def get_ports(parsed_wsdl) do
    services = get_toplevel_elements(parsed_wsdl, :"wsdl:tService")
    Enum.reduce(services, [], fn service, acc ->
      {:"wsdl:tService", _attrs, service_name, _docs, _choice, ports} = service
      Enum.reduce(ports, acc, fn
        {:"wsdl:tPort", _attrs, name, binding, _docs, choice}, acc ->
          Enum.reduce(choice, acc, fn
            {:"soap:tAddress", _attrs, _required, location}, acc ->
              [%{service: service_name, port: name, binding: binding, address: location} | acc]
            _, acc -> acc # non-soap bindings are ignored
          end)
          _, acc -> acc
      end)
    end)
  end


  # %% returns [#operation{}]
  def get_operations(parsed_wsdl, ports) do
    bindings = get_toplevel_elements(parsed_wsdl, :"wsdl:tBinding")
    Enum.reduce(bindings, [], fn {:"wsdl:tBinding", _attrs, binding, _type, _docs, _choice, ops}, acc ->
      Enum.reduce(ops, acc, fn {:"wsdl:tBindingOperation", _attrs, name, _docs, choice, _input, _output, _fault}, acc ->
        case choice do
          [{:"soap:tOperation", _attrs, _required, action, _style}] ->
            # lookup Binding in Ports, and create a combined result
            operations =
              ports
              |> Enum.filter(fn port -> :erlsom_lib.localName(port[:binding]) == binding end)
              |> Enum.map(fn port ->
                %{service: port.service, port: port.port, operation: name, binding: binding, address: port.address, action: action}
              end)
            operations ++ acc
          _ ->  acc
        end
      end)
    end)
  end

  def get_imports(parsed_wsdl) do
    parsed_wsdl
    |> get_toplevel_elements(:"wsdl:tImport")
    |> Enum.map(fn {:"wsdl:tImport", _attrs, _namespace, location, _docs} -> to_string(location) end)
  end
end