Allow remediation points to be multipliable

When a cop has a score/limit we now multiply a per violation amount of
points by the overage of the violation. eg: 25/20 would multiply the
per violation points by 5

This also changes `config/cops.yml` cops to have two values,
`base_points` and `violation_points`.

Since Rubocop violations don't directly expose the score/limit we check
for the presence and extract the values from the format of
`[score/limit]` in the violation message.

Author: BlakeWilliams

.rubocop.yml

@@ -4,6 +4,9 @@ Metrics/ModuleLength:
 Style/ClassAndModuleChildren:
   Exclude:
     - 'spec/**/*'
+Metrics/LineLength:
+  Exclude:
+    - 'spec/**/*'
 Style/Documentation:
   Enabled: false
 Style/FileName:
@@ -17,3 +20,8 @@ Style/StringLiterals:
   Enabled: false
 Style/TrailingComma:
   Enabled: false
+Style/DotPosition:
+  EnforcedStyle: 'trailing'
+  Enabled: true
+Style/MultilineOperationIndentation:
+  Enabled: false

Gemfile

@@ -3,6 +3,7 @@ source 'https://rubygems.org'
 gem "activesupport", require: false
 gem "rubocop", require: false
 gem "rubocop-rspec", require: false
+gem "safe_yaml"
 gem "pry", require: false
 
 group :test do

Gemfile.lock

@@ -42,6 +42,7 @@ GEM
       ruby-progressbar (~> 1.4)
     rubocop-rspec (1.3.0)
     ruby-progressbar (1.7.5)
+    safe_yaml (1.0.4)
     slop (3.6.0)
     thread_safe (0.3.5)
     tzinfo (1.2.2)
@@ -59,3 +60,4 @@ DEPENDENCIES
   rake
   rubocop
   rubocop-rspec
+  safe_yaml

config/cops.yml

@@ -1 +1,24 @@
-Metrics/ClassLength: 400_000
+Metrics/AbcSize:
+  violation_points: 100_000
+Metrics/BlockNesting:
+  base_points: 30_000
+Metrics/ClassLength:
+  base_points: 400_000
+Metrics/CyclomaticComplexity:
+  base_points: 75_000
+  violation_points: 10_000
+Metrics/LineLength:
+  base_points: 20_000
+  violation_points: 5_000
+Metrics/MethodLength:
+  base_points: 50_000
+  violation_points: 10_000
+Metrics/ModuleLength:
+  base_points: 500_000
+  violation_points: 5_000
+Metrics/ParameterList:
+  base_points: 10_000
+  violation_points: 50_000
+Metrics/PerceivedComplexity:
+  base_points: 50_000
+  violation_points: 5000

lib/cc/engine/rubocop.rb

@@ -5,14 +5,13 @@
 require "cc/engine/category_parser"
 require "cc/engine/file_list_resolver"
 require "cc/engine/lockfile_specs"
+require "cc/engine/violation_decorator"
 require "active_support"
 require "active_support/core_ext"
 
 module CC
   module Engine
     class Rubocop
-      DEFAULT_REMEDIATION_POINTS = 200_000
-
       def initialize(code, engine_config, io)
         @code = code
         @engine_config = engine_config || {}
@@ -45,7 +44,8 @@ def category(cop_name)
       def inspect_file(path)
         parsed = RuboCop::ProcessedSource.from_file(path)
         rubocop_team_for_path(path).inspect_file(parsed).each do |violation|
-          json = violation_json(violation, local_path(path))
+          decorated_violation = ViolationDecorator.new(violation)
+          json = violation_json(decorated_violation, local_path(path))
           @io.print "#{json}\0"
         end
       end
@@ -103,7 +103,7 @@ def violation_json(violation, local_path)
           check_name: "Rubocop/#{violation.cop_name}",
           description: violation.message,
           categories: [category(violation.cop_name)],
-          remediation_points: remediation_points_for(violation.cop_name),
+          remediation_points: violation.remediation_points,
           location: {
             path: local_path,
             positions: violation_positions(violation.location),
@@ -130,22 +130,6 @@ def cops
           RuboCop::Cop::Cop.non_rails
         end
       end
-
-      def remediation_points_for(cop_name)
-        cop_list.fetch(cop_name, DEFAULT_REMEDIATION_POINTS)
-      end
-
-      def cop_list
-        return @cop_list if @cop_list
-
-        cops_path = File.expand_path(
-          File.join(File.dirname(__FILE__), "../../../config/cops.yml")
-        )
-
-        File.open(cops_path, "r") do |file|
-          @cop_list = YAML.load(file.read)
-        end
-      end
     end
   end
 end

lib/cc/engine/violation_decorator.rb

@@ -0,0 +1,56 @@
+require 'safe_yaml'
+
+module CC
+  module Engine
+    class ViolationDecorator < SimpleDelegator
+      MULTIPLIER_REGEX = %r{\[([\d\.]+)\/([\d\.]+)\]}
+
+      DEFAULT_REMEDIATION_POINTS = 200_000
+      DEFAULT_POINTS_PER_VIOLATION = 50_000
+
+      def remediation_points
+        if multiplier?
+          base_points + violation_points
+        else
+          base_points
+        end
+      end
+
+      private
+
+      def base_points
+        cop_list.
+          fetch(cop_name, {}).
+          fetch("base_points", DEFAULT_REMEDIATION_POINTS)
+      end
+
+      def violation_points
+        per_violation_points = cop_list.
+          fetch(cop_name, {}).
+          fetch("violation_points", DEFAULT_POINTS_PER_VIOLATION)
+
+        per_violation_points * multiplier
+      end
+
+      def multiplier
+        result = message.scan(MULTIPLIER_REGEX)
+        score, max = result[0]
+        score.to_i - max.to_i
+      end
+
+      def multiplier?
+        message.match(MULTIPLIER_REGEX)
+      end
+
+      def cop_list
+        return @cop_list if @cop_list
+
+        cops_path = File.expand_path(
+          File.join(File.dirname(__FILE__), "../../../config/cops.yml")
+        )
+
+        @cop_list = YAML.load_file(cops_path)
+      end
+    end
+  end
+end

spec/cc/engine/violation_decorator_spec.rb

@@ -0,0 +1,37 @@
+require "spec_helper"
+require "cc/engine/violation_decorator"
+
+module CC::Engine
+  describe ViolationDecorator do
+    describe "#remediation points" do
+      it "returns remediation points for violation" do
+        fake_violation = Minitest::Mock.new
+        fake_violation.expect :cop_name, :unknown_cop
+        fake_violation.expect :message, "This has no multiplier!"
+
+        decorated_violation = ViolationDecorator.new(fake_violation)
+
+        decorated_violation.remediation_points.must_equal(
+          ViolationDecorator::DEFAULT_REMEDIATION_POINTS
+        )
+      end
+
+      it "returns remedation points plus per violation points multiplied by overage" do
+        fake_violation = Minitest::Mock.new
+        fake_violation.expect :cop_name, :unknown_cop
+        fake_violation.expect :cop_name, :unknown_cop
+        fake_violation.expect :message, "This has [22/20] multiplier!"
+        fake_violation.expect :message, "This has [22/20] multiplier!"
+
+        decorated_violation = ViolationDecorator.new(fake_violation)
+
+        violation_pointss = ViolationDecorator::DEFAULT_POINTS_PER_VIOLATION * 2
+        base_points = ViolationDecorator::DEFAULT_REMEDIATION_POINTS
+
+        decorated_violation.remediation_points.must_equal(
+          violation_pointss + base_points
+        )
+      end
+    end
+  end
+end