Show affected code while using a default formatter

README.md

@@ -33,15 +33,19 @@ Inspecting 107 files.
 
 ...............F.....................F....................................................................
 
-src/ameba/rule/unneeded_disable_directive.cr:29:7
-Lint/UselessAssign: Useless assignment to variable `s`
-
-src/ameba/formatter/flycheck_formatter.cr:5:21
+src/ameba/formatter/flycheck_formatter.cr:4:33
 Lint/UnusedArgument: Unused argument `location`
+> source.issues.each do |e, location|
+                            ^
 
-Finished in 248.9 milliseconds
+src/ameba/formatter/base_formatter.cr:12:7
+Lint/UselessAssign: Useless assignment to variable `s`
+> return s += issues.size
+         ^
 
-107 inspected, 2 failures.
+Finished in 542.64 milliseconds
+
+129 inspected, 2 failures.
 
 ```
 

spec/ameba/cli/cmd_spec.cr

@@ -62,6 +62,11 @@ module Ameba::Cli
         c.colors?.should be_false
       end
 
+      it "accepts --without-affected-code flag" do
+        c = Cli.parse_args %w(--without-affected-code)
+        c.without_affected_code?.should be_true
+      end
+
       it "doesn't disable colors by default" do
         c = Cli.parse_args %w(--all)
         c.colors?.should be_true

spec/ameba/formatter/dot_formatter_spec.cr

@@ -50,6 +50,37 @@ module Ameba::Formatter
           log.should contain "NamedRuleError"
         end
 
+        it "writes affected code by default" do
+          output.clear
+          s = Source.new(%(
+            a = 22
+            puts a
+          )).tap do |source|
+            source.add_issue(DummyRule.new, {1, 5}, "DummyRuleError")
+          end
+          subject.finished [s]
+          log = output.to_s
+          log.should contain "> a = 22"
+          log.should contain "      \e[33m^\e[0m"
+        end
+
+        it "doesn't write affected code if it is disabled" do
+          output.clear
+          s = Source.new(%(
+            a = 22
+            puts a
+          )).tap do |source|
+            source.add_issue(DummyRule.new, {1, 5}, "DummyRuleError")
+          end
+
+          formatter = DotFormatter.new output
+          formatter.config[:without_affected_code] = true
+          formatter.finished [s]
+          log = output.to_s
+          log.should_not contain "> a = 22"
+          log.should_not contain "      \e[33m^\e[0m"
+        end
+
         it "does not write disabled issues" do
           s = Source.new ""
           s.add_issue(DummyRule.new, location: {1, 1},

src/ameba/cli/cmd.cr

@@ -27,6 +27,7 @@ module Ameba::Cli
     property except : Array(String)?
     property? all = false
     property? colors = true
+    property? without_affected_code = false
   end
 
   def parse_args(args, opts = Opts.new)
@@ -68,6 +69,11 @@ module Ameba::Cli
         opts.config = ""
       end
 
+      parser.on("--without-affected-code",
+        "Stop showing affected code while using a default formatter") do
+        opts.without_affected_code = true
+      end
+
       parser.on("--no-color", "Disable colors") do
         opts.colors = false
       end
@@ -91,6 +97,7 @@ module Ameba::Cli
     if name = opts.formatter
       config.formatter = name
     end
+    config.formatter.config[:without_affected_code] = opts.without_affected_code?
   end
 
   private def print_version

src/ameba/formatter/base_formatter.cr

@@ -6,6 +6,7 @@ module Ameba::Formatter
   class BaseFormatter
     # TODO: allow other IOs
     getter output : IO::FileDescriptor | IO::Memory
+    getter config = {} of Symbol => String | Bool
 
     def initialize(@output = STDOUT)
     end

src/ameba/formatter/dot_formatter.cr

@@ -19,15 +19,25 @@ module Ameba::Formatter
     end
 
     # Reports a message when inspection is finished.
-    def finished(sources)
-      output << "\n\n"
+    def finished(sources, break_line = "\n\n")
+      output << break_line
+
+      show_affected_code = !config[:without_affected_code]?
       failed_sources = sources.reject &.valid?
 
       failed_sources.each do |source|
         source.issues.each do |issue|
           next if issue.disabled?
-          output << "#{issue.location}\n".colorize(:cyan)
-          output << "#{issue.rule.name}: #{issue.message}\n\n".colorize(:red)
+          next if (location = issue.location).nil?
+
+          output << "#{location}\n".colorize(:cyan)
+          output << "#{issue.rule.name}: #{issue.message}\n".colorize(:red)
+
+          if show_affected_code && (code = affected_code(source, location))
+            output << code
+          end
+
+          output << "\n"
         end
       end
 
@@ -77,5 +87,25 @@ module Ameba::Formatter
 
       "#{total} inspected, #{failures} failure#{s}.\n".colorize color
     end
+
+    private def affected_code(source, location, max_length = 100, placeholder = " ...", prompt = "> ")
+      line, column = location.line_number, location.column_number
+      affected_line = source.lines[line - 1]?
+
+      return unless affected_line
+
+      if affected_line.size > max_length && column < max_length
+        affected_line = affected_line[0, max_length - placeholder.size - 1] + placeholder
+      end
+
+      stripped = affected_line.lstrip
+      position = column - (affected_line.size - stripped.size) + prompt.size
+
+      String.build do |str|
+        str << prompt << stripped << "\n"
+        str << " " * (position - 1)
+        str << "^".colorize(:yellow)
+      end
+    end
   end
 end

src/ameba/rule/layout/line_length.cr

@@ -22,7 +22,7 @@ module Ameba::Rule::Layout
       source.lines.each_with_index do |line, index|
         next unless line.size > max_length
 
-        issue_for({index + 1, line.size}, MSG)
+        issue_for({index + 1, max_length + 1}, MSG)
       end
     end
   end