Add `TomTom::Matrix`

A new component to the `TomTom` module that asks TomTom's Matrix API
endpoint
(https://developer.tomtom.com/online-routing/online-routing-documentation/matrix-routing)
to compute `WayCost`s. The matrix API will give us all costs between
each pair of coordinates. This will enable us to provide costs for any
combination of points in a journey pattern.

Given a list of `WayCost`s, it will send all points from those costs to
the matrix API and return a list of all non-zero `WayCost`s between all
pairs of coordinates.

`points_from_way_costs()` extracts unique coordinates from the
`WayCost`s.

`points_as_params()` builds a list of points in the format expected by
the matrix API.

The response from the matrix API is formatted as a two-dimensional array
consisting of rows and columns that pair each "origin" point with each
"destination" point. We loop through this matrix and construct new
`WayCost` objects for each pair of coordinates.

At the moment, I haven't figured out how I want to save `WayCost` IDs
when creating the new pairs. Leaving that for later.

Refs #6222

2 files changed, 93 insertions, 0 deletions

diff --git a/lib/tom_tom.rb b/lib/tom_tom.rb
index a1a2bda43..fcebcc7ac 100644
--- a/lib/tom_tom.rb
+++ b/lib/tom_tom.rb
@@ -19,4 +19,8 @@ module TomTom
   def self.batch(way_costs)
     TomTom::Batch.new(@connection).batch(way_costs)
   end
+
+  def self.matrix(way_costs)
+    TomTom::Matrix.new(@connection).matrix(way_costs)
+  end
 end
diff --git a/lib/tom_tom/matrix.rb b/lib/tom_tom/matrix.rb
new file mode 100644
index 000000000..985055dae
--- /dev/null
+++ b/lib/tom_tom/matrix.rb
@@ -0,0 +1,89 @@
+module TomTom
+  class Matrix
+    def initialize(connection)
+      @connection = connection
+    end
+
+    def matrix(way_costs)
+      points = points_from_way_costs(way_costs)
+      points = points_as_params(points)
+
+      response = @connection.post do |req|
+        req.url '/routing/1/matrix/json'
+        req.headers['Content-Type'] = 'application/json'
+
+        req.params[:routeType] = 'shortest'
+        req.params[:travelMode] = 'bus'
+
+        req.body = {
+          origins: points,
+          destinations: points
+        }.to_json
+      end
+
+      extract_costs_to_way_costs!(
+        way_costs,
+        points,
+        JSON.parse(response.body)
+      )
+    end
+
+    def points_from_way_costs(way_costs)
+      points = Set.new
+
+      way_costs.each do |way_cost|
+        points.add(way_cost.departure)
+        points.add(way_cost.arrival)
+      end
+
+      points
+    end
+
+    def points_as_params(points)
+      points.map do |latlng|
+        {
+          point: {
+            latitude: latlng.lat,
+            longitude: latlng.lng
+          }
+        }
+      end
+    end
+
+    # TODO: We actually need to create new WayCost objects to hold the new dot connections given to us by the matrix API.
+    def extract_costs_to_way_costs!(way_costs, points, matrix_json)
+      way_costs = []
+
+      # `row` and `column` order is the same as `points`
+      matrix_json['matrix'].each_with_index do |row, row_i|
+        row.each_with_index do |column, column_i|
+          next if column['statusCode'] != 200
+
+          distance = column['response']['routeSummary']['lengthInMeters']
+
+          # Ignore costs between a point and itself (e.g. from A to A)
+          next if distance == 0
+
+          departure = points[row_i]
+          arrival = points[column_i]
+
+          way_costs << WayCost.new(
+            departure: Geokit::LatLng.new(
+              departure[:point][:latitude],
+              departure[:point][:longitude]
+            ),
+            arrival: Geokit::LatLng.new(
+              arrival[:point][:latitude],
+              arrival[:point][:longitude]
+            ),
+            distance: distance,
+            time: column['response']['routeSummary']['travelTimeInSeconds']
+            # id: 'TODO: figure out how to add combined stop IDs'
+          )
+        end
+      end
+
+      way_costs
+    end
+  end
+end