module Shoulda # :nodoc:
  module Assertions
    # Asserts that two arrays contain the same elements, the same number of times.  Essentially ==, but unordered.
    #
    #   assert_same_elements([:a, :b, :c], [:c, :a, :b]) => passes
    def assert_same_elements(a1, a2, msg = nil)
      [:select, :inject, :size].each do |m|
        [a1, a2].each {|a| assert_respond_to(a, m, "Are you sure that #{a.inspect} is an array?  It doesn't respond to #{m}.") }
      end

      assert a1h = a1.inject({}) { |h,e| h[e] = a1.select { |i| i == e }.size; h }
      assert a2h = a2.inject({}) { |h,e| h[e] = a2.select { |i| i == e }.size; h }

      assert_equal(a1h, a2h, msg)
    end

    # Asserts that the given collection contains item x.  If x is a regular expression, ensure that
    # at least one element from the collection matches x.  +extra_msg+ is appended to the error message if the assertion fails.
    #
    #   assert_contains(['a', '1'], /\d/) => passes
    #   assert_contains(['a', '1'], 'a') => passes
    #   assert_contains(['a', '1'], /not there/) => fails
    def assert_contains(collection, x, extra_msg = "")
      collection = [collection] unless collection.is_a?(Array)
      msg = "#{x.inspect} not found in #{collection.to_a.inspect} #{extra_msg}"
      case x
      when Regexp
        assert(collection.detect { |e| e =~ x }, msg)
      else         
        assert(collection.include?(x), msg)
      end
    end

    # Asserts that the given collection does not contain item x.  If x is a regular expression, ensure that
    # none of the elements from the collection match x.
    def assert_does_not_contain(collection, x, extra_msg = "")
      collection = [collection] unless collection.is_a?(Array)
      msg = "#{x.inspect} found in #{collection.to_a.inspect} " + extra_msg
      case x
      when Regexp
        assert(!collection.detect { |e| e =~ x }, msg)
      else         
        assert(!collection.include?(x), msg)
      end
    end

    # Asserts that the given matcher returns true when +target+ is passed to #matches?
    def assert_accepts(matcher, target, options = {})
      if matcher.respond_to?(:in_context)
        matcher.in_context(self)
      end

      if matcher.matches?(target)
        assert_block { true }
        if options[:message]
          assert_match options[:message], matcher.negative_failure_message
        end
      else
        assert_block(matcher.failure_message) { false }
      end
    end

    # Asserts that the given matcher returns false when +target+ is passed to #matches?
    def assert_rejects(matcher, target, options = {})
      if matcher.respond_to?(:in_context)
        matcher.in_context(self)
      end

      unless matcher.matches?(target)
        assert_block { true }
        if options[:message]
          assert_match options[:message], matcher.failure_message
        end
      else
        assert_block(matcher.negative_failure_message) { false }
      end
    end
  end
end
