Add --autocorrect CLI option

src/ameba/cli/cmd.cr

@@ -8,6 +8,7 @@ module Ameba::Cli
   def run(args = ARGV)
     opts = parse_args args
     config = Config.load opts.config, opts.colors?
+    config.autocorrect = opts.autocorrect?
 
     if globs = opts.globs
       config.globs = globs
@@ -47,6 +48,7 @@ module Ameba::Cli
     property? all = false
     property? colors = true
     property? without_affected_code = false
+    property? autocorrect = false
   end
 
   def parse_args(args, opts = Opts.new)
@@ -89,6 +91,10 @@ module Ameba::Cli
         opts.all = true
       end
 
+      parser.on("-a", "--autocorrect", "Autocorrect issues") do
+        opts.autocorrect = true
+      end
+
       parser.on("--gen-config",
         "Generate a configuration file acting as a TODO list") do
         opts.formatter = :todo
@@ -133,6 +139,7 @@ module Ameba::Cli
     if name = opts.formatter
       config.formatter = name
     end
+    config.formatter.config[:autocorrect] = opts.autocorrect?
     config.formatter.config[:without_affected_code] =
       opts.without_affected_code?
   end

src/ameba/config.cr

@@ -54,6 +54,8 @@ class Ameba::Config
   # ```
   property excluded : Array(String)
 
+  property? autocorrect = false
+
   @rule_groups : Hash(String, Array(Rule::Base))
 
   # Creates a new instance of `Ameba::Config` based on YAML parameters.

src/ameba/formatter/dot_formatter.cr

@@ -36,7 +36,15 @@ module Ameba::Formatter
           next if issue.disabled?
           next if (location = issue.location).nil?
 
-          output.puts location.colorize(:cyan)
+          output.print location.colorize(:cyan)
+          if issue.correctable?
+            if config[:autocorrect]?
+              output.print " [Corrected]".colorize(:green)
+            else
+              output.print " [Correctable]".colorize(:yellow)
+            end
+          end
+          output.puts
           output.puts \
             "[#{issue.rule.severity.symbol}] " \
             "#{issue.rule.name}: " \

src/ameba/runner.cr

@@ -29,6 +29,8 @@ module Ameba
     # Checks for unneeded disable directives. Always inspects a source last
     @unneeded_disable_directive_rule : Rule::Base?
 
+    private getter? autocorrect : Bool
+
     # Instantiates a runner using a `config`.
     #
     # ```
@@ -43,6 +45,7 @@ module Ameba
       @formatter = config.formatter
       @severity = config.severity
       @rules = config.rules.select(&.enabled).reject!(&.special?)
+      @autocorrect = config.autocorrect?
 
       @unneeded_disable_directive_rule =
         config.rules
@@ -50,6 +53,7 @@ module Ameba
     end
 
     protected def initialize(@rules, @sources, @formatter, @severity)
+      @autocorrect = false
     end
 
     # Performs the inspection. Iterates through all sources and test it using
@@ -89,12 +93,16 @@ module Ameba
     private def run_source(source)
       @formatter.source_started source
 
+      # TODO: run autocorrection recursively. A new `Issue#source` property must
+      #       be added so that `affected_code` will return the code from the old
+      #       source instead of the autocorrected one.
       if @syntax_rule.catch(source).valid?
         @rules.each do |rule|
           next if rule.excluded?(source)
           rule.test(source)
         end
         check_unneeded_directives(source)
+        autocorrect(source) if autocorrect?
       end
 
       @formatter.source_finished source
@@ -135,5 +143,12 @@ module Ameba
         rule.test(source)
       end
     end
+
+    private def autocorrect(source)
+      corrected_code = Source::Corrector.correct(source)
+      return unless corrected_code
+
+      File.write(source.path, corrected_code)
+    end
   end
 end