require "spec_helper"

module ModelSpecHelper

  def create_example
    Node.features(0.2, 0.3, 0.4, 0.5)
  end

  def create_problem
    problem = Problem.new
    features = [Node.features([0.2,0.3,0.4,0.4]),
                Node.features([0.1,0.5,0.1,0.9]),
                Node.features([0.2,0.2,0.6,0.5]),
                Node.features([0.3,0.1,0.5,0.9])]
    problem.set_examples([1,2,1,2], features)
    problem
  end

  def create_parameter
    parameter = SvmParameter.new
    parameter.cache_size = 50 # mb
    parameter.eps = 0.01
    parameter.c = 10
    parameter.probability = 1
    parameter
  end

end

describe "The Libsvm::Model class interface" do
  include ModelSpecHelper

  before(:each) do
    @problem = create_problem
    @parameter = create_parameter
  end

  it "results from training on a problem under a certain parameter set" do
    model = Model.train(@problem,@parameter)
    model.should_not be_nil
  end

  it "can do cross-validation" do
    labels = Model.cross_validation(@problem, @parameter, fold=2)
    labels.should == [anything, anything, anything, anything]
  end
end

describe "A saved model" do
  include ModelSpecHelper

  before(:each) do
    @filename = "tmp/svm_model.model"
    model = Model.train(create_problem, create_parameter)
    model.save(@filename)
  end

  it "can be loaded" do
    model = Model.load(@filename)
    model.should_not be_nil
  end

  after(:each) do
    File.delete(@filename) rescue nil
  end
end

describe "An Libsvm model" do
  include ModelSpecHelper

  before(:each) do
    @problem = create_problem
    @parameter = create_parameter
    @model = Model.train(@problem, @parameter)
    @file_path = "tmp/svm_model.model"
    File.delete(@file_path) if File.exists?(@file_path)
  end

  it "can be saved to a file" do
    @model.save(@file_path)
    File.exist?(@file_path).should be_true
  end

  it "can be asked for it's svm_type" do
    @model.svm_type.should == SvmType::C_SVC
  end

  it "can be asked for it's number of classes (aka. labels)" do
    @model.classes.should == 2
  end

  it "can predict" do
    prediction = @model.predict(create_example)
    prediction.should_not be_nil
  end

  it "can predict probability" do
    prediction, probabilities = @model.predict_probability(create_example)
    prediction.should_not be_nil
    probabilities.should have(@model.classes).items
    probabilities.each { |e| e.should_not be_nil }
  end
end