require_relative "../helper.rb"

describe Ashton::Shader do
  before :all do
    $window = Gosu::Window.new 16, 16, false
  end

  let(:subject) { described_class.new}
  let(:program) { subject.instance_variable_get :@program }

  after :each do
    glUseProgram 0
  end

  describe "initialize" do
    it "should fail if the built-in fragment shader doesn't exist" do
      ->{ described_class.new fragment: :fish }.should raise_error Ashton::ShaderLoadError
    end

    it "should fail if the built-in vertex shader doesn't exist" do
      ->{ described_class.new vertex: :fish }.should raise_error Ashton::ShaderLoadError
    end

    it "should fail if the file-based fragment shader doesn't exist or is bad source" do
      ->{ described_class.new fragment: "/fish.frag" }.should raise_error Ashton::ShaderCompileError
    end

    it "should fail if the file-based fragment shader doesn't exist or is bad source" do
      ->{ described_class.new vertex: "/fish.vert" }.should raise_error Ashton::ShaderCompileError
    end

    it "should set uniform values from the options hash" do
      any_instance_of described_class do |shader|
        mock(shader, :[]=).with :frog, 12
        mock(shader, :[]=).with :fish_paste, 15.0
      end

      described_class.new uniforms: { frog: 12, fish_paste: 15.0 }
    end

    it "should fail if requested to set nonexistent uniform values in the options hash" do
      ->{ described_class.new uniforms: { frog: 12 }} .should raise_error Ashton::ShaderUniformError
    end
  end

  describe "dup" do
    it "should create a new object containing the same source" do
      new_shader = subject.dup
      new_shader.vertex_source.should eq subject.vertex_source
      new_shader.fragment_source.should eq subject.fragment_source
    end
  end

  describe "enable" do
    context "with a block" do
      it "should fail if the shader is already active" do
        glUseProgram program

        ->{ subject.enable {} }.should raise_error Ashton::ShaderError
      end

      it "should pass itself into the block" do
        shader = nil
        subject.enable do |s|
          shader = s
        end

        shader.should eq subject
      end

      it "should be current within the block?" do
        subject.enable do
          subject.should be_current
        end
      end

      it "should be not current after the block" do
        subject.enable do
        end

        subject.should_not be_current
      end
    end

    context "without a block" do
      it "should fail if the shader is already active" do
        glUseProgram program

        ->{ subject.enable }.should raise_error Ashton::ShaderError
      end

      it "should toggle current?" do
        ->{ subject.enable }.should change(subject, :current?).from(false).to true
      end
    end
  end

  describe "disable" do
    it "should fail if the shader is not active" do
      -> { subject.disable }.should raise_error Ashton::ShaderError
    end

    it "should toggle current?" do
      subject.enable
      ->{ subject.disable }.should change(subject, :current?).from(true).to false
    end
  end

  describe "current?" do
    it "should be true if the program is current" do
      glUseProgram program
      subject.should be_current
    end

    it "should be false if the program isn't current" do
      glUseProgram 0
      subject.should_not be_current
    end
  end

  describe "image=" do
    pending
  end

  describe "color=" do
    pending
  end

  describe "[]=" do
    pending
  end

  describe "[]" do
    pending "implementation"
  end

  describe "uniform_location" do
    pending
  end

  describe "attribute_location" do
    pending
  end

  describe "compile" do
    pending
  end

  describe "link" do
    pending
  end
end