module Thoughtbot # :nodoc:
  module Shoulda
    VERSION = '2.0.4'

    class << self
      attr_accessor :contexts
      def contexts # :nodoc:
        @contexts ||= []
      end

      def current_context # :nodoc:
        self.contexts.last
      end

      def add_context(context) # :nodoc:
        self.contexts.push(context)
      end

      def remove_context # :nodoc:
        self.contexts.pop
      end
    end

    # == Should statements
    #
    # Should statements are just syntactic sugar over normal Test::Unit test methods.  A should block
    # contains all the normal code and assertions you're used to seeing, with the added benefit that
    # they can be wrapped inside context blocks (see below).
    #
    # === Example:
    #
    #  class UserTest << Test::Unit::TestCase
    #
    #    def setup
    #      @user = User.new("John", "Doe")
    #    end
    #
    #    should "return its full name"
    #      assert_equal 'John Doe', @user.full_name
    #    end
    #
    #  end
    #
    # ...will produce the following test:
    # * <tt>"test: User should return its full name. "</tt>
    #
    # Note: The part before <tt>should</tt> in the test name is gleamed from the name of the Test::Unit class.
    #
    # Should statements can also take a Proc as a <tt>:before </tt>option.  This proc runs after any
    # parent context's setups but before the current context's setup.
    #
    # === Example:
    #
    #  context "Some context" do
    #    setup { puts("I run after the :before proc") }
    #
    #    should "run a :before proc", :before => lambda { puts("I run before the setup") }  do
    #      assert true
    #    end
    #  end

    def should(name, options = {}, &blk)
      if Shoulda.current_context
        block_given? ? Shoulda.current_context.should(name, options, &blk) : Should.current_context.should_eventually(name)
      else
        context_name = self.name.gsub(/Test/, "")
        context = Thoughtbot::Shoulda::Context.new(context_name, self) do
          block_given? ? should(name, options, &blk) : should_eventually(name)
        end
        context.build
      end
    end

    # == Before statements
    #
    # Before statements are should statements that run before the current
    # context's setup. These are especially useful when setting expectations.
    #
    # === Example:
    #
    #  class UserControllerTest < Test::Unit::TestCase
    #    context "the index action" do
    #      setup do
    #        @users = [Factory(:user)]
    #        User.stubs(:find).returns(@users)
    #      end
    #
    #      context "on GET" do
    #        setup { get :index }
    #
    #        should_respond_with :success
    #
    #        # runs before "get :index"
    #        before_should "find all users" do
    #          User.expects(:find).with(:all).returns(@users)
    #        end
    #      end
    #    end
    #  end
    def before_should(name, &blk)
      should(name, :before => blk) { assert true }
    end

    # Just like should, but never runs, and instead prints an 'X' in the Test::Unit output.
    def should_eventually(name, options = {}, &blk)
      context_name = self.name.gsub(/Test/, "")
      context = Thoughtbot::Shoulda::Context.new(context_name, self) do
        should_eventually(name, &blk)
      end
      context.build
    end

    # == Contexts
    #
    # A context block groups should statements under a common set of setup/teardown methods.
    # Context blocks can be arbitrarily nested, and can do wonders for improving the maintainability
    # and readability of your test code.
    #
    # A context block can contain setup, should, should_eventually, and teardown blocks.
    #
    #  class UserTest << Test::Unit::TestCase
    #    context "A User instance" do
    #      setup do
    #        @user = User.find(:first)
    #      end
    #
    #      should "return its full name"
    #        assert_equal 'John Doe', @user.full_name
    #      end
    #    end
    #  end
    #
    # This code will produce the method <tt>"test: A User instance should return its full name. "</tt>.
    #
    # Contexts may be nested.  Nested contexts run their setup blocks from out to in before each
    # should statement.  They then run their teardown blocks from in to out after each should statement.
    #
    #  class UserTest << Test::Unit::TestCase
    #    context "A User instance" do
    #      setup do
    #        @user = User.find(:first)
    #      end
    #
    #      should "return its full name"
    #        assert_equal 'John Doe', @user.full_name
    #      end
    #
    #      context "with a profile" do
    #        setup do
    #          @user.profile = Profile.find(:first)
    #        end
    #
    #        should "return true when sent :has_profile?"
    #          assert @user.has_profile?
    #        end
    #      end
    #    end
    #  end
    #
    # This code will produce the following methods
    # * <tt>"test: A User instance should return its full name. "</tt>
    # * <tt>"test: A User instance with a profile should return true when sent :has_profile?. "</tt>
    #
    # <b>Just like should statements, a context block can exist next to normal <tt>def test_the_old_way; end</tt>
    # tests</b>.  This means you do not have to fully commit to the context/should syntax in a test file.

    def context(name, &blk)
      if Shoulda.current_context
        Shoulda.current_context.context(name, &blk)
      else
        context = Thoughtbot::Shoulda::Context.new(name, self, &blk)
        context.build
      end
    end

    class Context # :nodoc:

      attr_accessor :name               # my name
      attr_accessor :parent             # may be another context, or the original test::unit class.
      attr_accessor :subcontexts        # array of contexts nested under myself
      attr_accessor :setup_blocks       # blocks given via setup methods
      attr_accessor :teardown_blocks    # blocks given via teardown methods
      attr_accessor :shoulds            # array of hashes representing the should statements
      attr_accessor :should_eventuallys # array of hashes representing the should eventually statements

      def initialize(name, parent, &blk)
        Shoulda.add_context(self)
        self.name               = name
        self.parent             = parent
        self.setup_blocks       = []
        self.teardown_blocks    = []
        self.shoulds            = []
        self.should_eventuallys = []
        self.subcontexts        = []

        merge_block(&blk)
        Shoulda.remove_context
      end

      def merge_block(&blk)
        blk.bind(self).call
      end

      def context(name, &blk)
        self.subcontexts << Context.new(name, self, &blk)
      end

      def setup(&blk)
        self.setup_blocks << blk
      end

      def teardown(&blk)
        self.teardown_blocks << blk
      end

      def should(name, options = {}, &blk)
        if block_given?
          self.shoulds << { :name => name, :before => options[:before], :block => blk }
        else
         self.should_eventuallys << { :name => name }
       end
      end

      def should_eventually(name, &blk)
        self.should_eventuallys << { :name => name, :block => blk }
      end

      def full_name
        parent_name = parent.full_name if am_subcontext?
        return [parent_name, name].join(" ").strip
      end

      def am_subcontext?
        parent.is_a?(self.class) # my parent is the same class as myself.
      end

      def test_unit_class
        am_subcontext? ? parent.test_unit_class : parent
      end

      def create_test_from_should_hash(should)
        test_name = ["test:", full_name, "should", "#{should[:name]}. "].flatten.join(' ').to_sym

        if test_unit_class.instance_methods.include?(test_name.to_s)
          warn "  * WARNING: '#{test_name}' is already defined"
        end

        context = self
        test_unit_class.send(:define_method, test_name) do
          begin
            context.run_parent_setup_blocks(self)
            should[:before].bind(self).call if should[:before]
            context.run_current_setup_blocks(self)
            should[:block].bind(self).call
          ensure
            context.run_all_teardown_blocks(self)
          end
        end
      end

      def run_all_setup_blocks(binding)
        run_parent_setup_blocks(binding)
        run_current_setup_blocks(binding)
      end

      def run_parent_setup_blocks(binding)
        self.parent.run_all_setup_blocks(binding) if am_subcontext?
      end

      def run_current_setup_blocks(binding)
        setup_blocks.each do |setup_block|
          setup_block.bind(binding).call
        end
      end

      def run_all_teardown_blocks(binding)
        teardown_blocks.reverse.each do |teardown_block|
          teardown_block.bind(binding).call
        end
        self.parent.run_all_teardown_blocks(binding) if am_subcontext?
      end

      def print_should_eventuallys
        should_eventuallys.each do |should|
          test_name = [full_name, "should", "#{should[:name]}. "].flatten.join(' ')
          puts "  * DEFERRED: " + test_name
        end
      end

      def build
        shoulds.each do |should|
          create_test_from_should_hash(should)
        end

        subcontexts.each { |context| context.build }

        print_should_eventuallys
      end

      def method_missing(method, *args, &blk)
        test_unit_class.send(method, *args, &blk)
      end

    end
  end
end