Add method to get ordered array of accept headers

Fix issue with header key including whitespace
Add singleton negotiator to base namespace

spec/negotiator_spec.cr

@@ -7,7 +7,18 @@ struct NegotiatorTest < ASPEC::TestCase
     @negotiator = ANG::Negotiator.new
   end
 
-  def test_exception_handling : Nil
+  def test_best_respects_quality : Nil
+    accept = @negotiator.best "text/html,text/*;q=0.7", {"text/html;q=0.5", "text/plain;q=0.9"}
+    accept = accept.should_not be_nil
+    accept.should be_a ANG::Accept
+    accept.type.should eq "text/plain"
+  end
+
+  def test_best_invalid_unstrict
+    @negotiator.best("/qwer", {"foo/bar"}, false).should be_nil
+  end
+
+  def test_best_exception_handling : Nil
     ex = expect_raises ANG::Exceptions::InvalidMediaType, "Invalid media type: '/qwer'." do
       @negotiator.best "foo/bar", {"/qwer"}
     end
@@ -90,7 +101,7 @@ struct NegotiatorTest < ASPEC::TestCase
       # IE8
       {"image/jpeg, application/x-ms-application, image/gif, application/xaml+xml, image/pjpeg, application/x-ms-xbap, */*", {"text/html", "application/xhtml+xml"}, {"text/html", nil}},
 
-      # wildcards with '+'
+      # wildcards with `+`
       {"application/vnd.api+json", {"application/json", "application/*+json"}, {"application/*+json", nil}},
       {"application/json;q=0.7, application/*+json;q=0.7", {"application/hal+json", "application/problem+json"}, {"application/hal+json", nil}},
       {"application/json;q=0.7, application/problem+*;q=0.7", {"application/hal+xml", "application/problem+xml"}, {"application/problem+xml", nil}},
@@ -98,4 +109,29 @@ struct NegotiatorTest < ASPEC::TestCase
       {"application/hal+json", {"application/ld+json", "application/hal+json", "application/xml", "text/xml", "application/json", "text/html"}, {"application/hal+json", nil}},
     }
   end
+
+  def test_ordered_elements_exception_handling : Nil
+    expect_raises ArgumentError, "The header string should not be empty." do
+      @negotiator.ordered_elements ""
+    end
+  end
+
+  @[DataProvider("test_ordered_elements_data_provider")]
+  def test_ordered_elements(header : String, expected : Indexable(String)) : Nil
+    elements = @negotiator.ordered_elements header
+
+    expected.each_with_index do |element, idx|
+      elements[idx].should be_a ANG::Accept
+      element.should eq elements[idx].value
+    end
+  end
+
+  def test_ordered_elements_data_provider : Tuple
+    {
+      {"/qwer", [] of String},                                                                                                                                                                    # Invalid
+      {"text/html, text/xml", {"text/html", "text/xml"}},                                                                                                                                         # Ordered as given if no quality modifier
+      {"text/html;q=0.3, text/html;q=0.7", {"text/html;q=0.7", "text/html;q=0.3"}},                                                                                                               # Ordered by quality modifier
+      {"text/*;q=0.3, text/html;q=0.7, text/html;level=1, text/html;level=2;q=0.4, */*;q=0.5", {"text/html;level=1", "text/html;q=0.7", "*/*;q=0.5", "text/html;level=2;q=0.4", "text/*;q=0.3"}}, # Ordered by quality modifier; one without wins
+    }
+  end
 end

src/abstract_negotiator.cr

@@ -1,4 +1,13 @@
 abstract class Athena::Negotiation::AbstractNegotiator
+  private record OrderKey, quality : Float32, index : Int32, value : String do
+    include Comparable(self)
+
+    def <=>(other : self) : Int32
+      return @index <=> other.index if @quality == other.quality
+      @quality > other.quality ? -1 : 1
+    end
+  end
+
   private abstract def create_header(header : String) : ANG::BaseAccept
 
   def best(header : String, priorities : Indexable(String), strict : Bool = false) : ANG::BaseAccept?
@@ -28,6 +37,28 @@ abstract class Athena::Negotiation::AbstractNegotiator
     match.nil? ? nil : accepted_priorties[match.index]
   end
 
+  def ordered_elements(header : String) : Array(ANG::BaseAccept)
+    raise ArgumentError.new "The header string should not be empty." if header.blank?
+
+    elements = Array(ANG::BaseAccept).new
+    order_keys = Array(OrderKey).new
+
+    idx = 0
+    self.parse_header(header) do |h|
+      element = self.create_header h
+      elements << element
+      order_keys << OrderKey.new element.quality, idx, element.value
+    rescue ex
+      # skip
+    ensure
+      idx += 1
+    end
+
+    order_keys.sort!.map do |ok|
+      elements[ok.index]
+    end
+  end
+
   protected def match(header : ANG::BaseAccept, priority : ANG::BaseAccept, index : Int32) : ANG::AcceptMatch?
     accept_type = header.type
     priority_type = priority.type
@@ -43,7 +74,7 @@ abstract class Athena::Negotiation::AbstractNegotiator
 
   private def parse_header(header : String, & : String ->) : Nil
     header.scan /(?:[^,\"]*+(?:"[^"]*+\")?)+[^,\"]*+/ do |match|
-      yield match[0] unless match[0].blank?
+      yield match[0].strip unless match[0].blank?
     end
   end
 

src/athena-negotiation.cr

@@ -11,8 +11,5 @@ require "./exceptions/*"
 alias ANG = Athena::Negotiation
 
 module Athena::Negotiation
+  class_getter(negotiator) { ANG::Negotiator.new }
 end
-
-# n = ANG::Negotiator.new
-
-# pp n.best "text/html; charset=UTF-8, application/pdf", ["text/html"]