TomTom::Matrix#points_from_way_costs: Include stop IDs with points

We need to persist stop IDs in order to properly construct `WayCost`
objects from the costs returned from the TomTom matrix API.

In order to persist stop IDs, my idea here is to group together a point
and its corresponding ID into a bucket. When we later
`#extract_costs_to_way_costs!`, we'll be able to grab the correct ID for
a given coordinate to create a `WayCost` from it.

Here, we create a new `TomTom::Matrix::Point` class that encapsulates a
coordinate and an ID, and build a `Set` of those. I needed an `#eql?`
and `#hash` method on `Point` as described in the `Set` documentation
(https://ruby-doc.org/stdlib-1.9.3/libdoc/set/rdoc/Set.html) in order to
properly maintain a unique set.

Refs #6222

2 files changed, 38 insertions, 2 deletions

diff --git a/lib/tom_tom/matrix.rb b/lib/tom_tom/matrix.rb
index 985055dae..4ef620f99 100644
--- a/lib/tom_tom/matrix.rb
+++ b/lib/tom_tom/matrix.rb
@@ -32,8 +32,20 @@ module TomTom
       points = Set.new
 
       way_costs.each do |way_cost|
-        points.add(way_cost.departure)
-        points.add(way_cost.arrival)
+        ids = way_cost.id.split('-')
+
+        points.add(
+          TomTom::Matrix::Point.new(
+            way_cost.departure,
+            ids[0]
+          )
+        )
+        points.add(
+          TomTom::Matrix::Point.new(
+            way_cost.arrival,
+            ids[1]
+          )
+        )
       end
 
       points
diff --git a/lib/tom_tom/matrix/point.rb b/lib/tom_tom/matrix/point.rb
new file mode 100644
index 000000000..4e9d11e68
--- /dev/null
+++ b/lib/tom_tom/matrix/point.rb
@@ -0,0 +1,24 @@
+module TomTom
+  class Matrix
+    class Point
+      attr_reader :coordinates, :id
+
+      def initialize(coordinates, id)
+        @coordinates = coordinates
+        @id = id
+      end
+
+      def ==(other)
+        other.is_a?(self.class) &&
+          @coordinates == other.coordinates &&
+          @id == other.id
+      end
+
+      alias :eql? :==
+
+      def hash
+        @coordinates.hash + @id.hash
+      end
+    end
+  end
+end