defmodule RDF.Test.Case do
  use ExUnit.CaseTemplate

  use RDF.Vocabulary.Namespace
  defvocab EX,
    base_uri: "http://example.com/",
    terms: [], strict: false

  alias RDF.{Dataset, Graph, Description}
  import RDF, only: [uri: 1]

  using do
    quote do
      alias RDF.{Dataset, Graph, Description}
      alias RDF.Test.Case.EX

      import RDF, only: [uri: 1, literal: 1, bnode: 1]
      import RDF.Test.Case
    end
  end

  ###############################
  # RDF.Description

  def description,          do: Description.new(EX.Subject)
  def description(content), do: Description.add(description(), content)

  def description_of_subject(%Description{subject: subject}, subject),
    do: true
  def description_of_subject(_, _),
    do: false

  def empty_description(%Description{predications: predications}),
    do: predications == %{}

  def description_includes_predication(desc, {predicate, object}) do
    desc.predications
    |> Map.get(predicate, %{})
    |> Enum.member?({object, nil})
  end

  ###############################
  # RDF.Graph

  def graph, do: unnamed_graph()

  def unnamed_graph, do: Graph.new

  def named_graph(name \\ EX.GraphName), do: Graph.new(name)

  def unnamed_graph?(%Graph{name: nil}), do: true
  def unnamed_graph?(_),                 do: false

  def named_graph?(%Graph{name: %URI{}}),     do: true
  def named_graph?(_),                        do: false
  def named_graph?(%Graph{name: name}, name), do: true
  def named_graph?(_, _),                     do: false

  def empty_graph?(%Graph{descriptions: descriptions}),
    do: descriptions == %{}

  def graph_includes_statement?(graph, {subject, _, _} = statement) do
    graph.descriptions
    |> Map.get(uri(subject), %{})
    |> Enum.member?(statement)
  end


  ###############################
  # RDF.Graph

  def dataset, do: unnamed_dataset()

  def unnamed_dataset, do: Dataset.new

  def named_dataset(name \\ EX.GraphName), do: Dataset.new(name)

  def unnamed_dataset?(%Dataset{name: nil}), do: true
  def unnamed_dataset?(_),                   do: false

  def named_dataset?(%Dataset{name: %URI{}}),     do: true
  def named_dataset?(_),                          do: false
  def named_dataset?(%Dataset{name: name}, name), do: true
  def named_dataset?(_, _),                       do: false

  def empty_dataset?(%Dataset{graphs: graphs}), do: graphs == %{}

  def dataset_includes_statement?(dataset, {_, _, _} = statement) do
    dataset
    |> Dataset.default_graph
    |> graph_includes_statement?(statement)
  end

  def dataset_includes_statement?(dataset, {subject, predicate, objects, nil}),
    do: dataset_includes_statement?(dataset, {subject, predicate, objects})

  def dataset_includes_statement?(dataset,
        {subject, predicate, objects, graph_context}) do
    dataset.graphs
    |> Map.get(uri(graph_context), named_graph(graph_context))
    |> graph_includes_statement?({subject, predicate, objects})
  end

end