refactor indentation with a dedicated class

Author: DannyBen

.rubocop.yml

@@ -19,6 +19,11 @@ Metrics/PerceivedComplexity:  { Exclude: [lib/bashly/config_validator.rb] }
 Metrics/MethodLength:         { Exclude: [lib/bashly/config_validator.rb] }
 Style/GuardClause:            { Exclude: [lib/bashly/config_validator.rb] }
 
+# False positive report of invalid use of a method that starts with `set_`
+Naming/AccessorMethodName:
+  Exclude:
+    - 'lib/bashly/indenter.rb'
+
 # FIXME: The `Command` class is too long
 Metrics/ClassLength: { Exclude: [lib/bashly/script/command.rb] }
 

lib/bashly/extensions/array.rb

@@ -1,19 +1,13 @@
+require 'bashly/indenter'
+
 class Array
   def indent(offset)
     return self unless offset.positive?
 
     indentation = ' ' * offset
-    heredoc_marker = nil
+    indenter = Indenter.new indentation
 
-    map do |line|
-      if heredoc_marker
-        heredoc_marker = nil if /^#{heredoc_marker}\n?$/.match?(line)
-        line
-      else
-        heredoc_marker = $1 if line =~ /<<-?\s*(\w+)/
-        "#{indentation}#{line}"
-      end
-    end
+    map { |line| indenter.indent line }
   end
 
   def nonuniq

lib/bashly/indenter.rb

@@ -0,0 +1,43 @@
+# A helper class, used by the `Array#indent` extension.
+# It will return the array of strings with all strings prefixed by `indentation`
+# unless the line is within a heredoc block.
+class Indenter
+  attr_reader :marker, :indentation
+
+  def initialize(indentation)
+    @indentation = indentation
+    @marker = nil
+  end
+
+  def indent(line)
+    if inside_heredoc?
+      reset_marker if heredoc_closed?(line)
+      line
+    else
+      set_heredoc_state(line)
+      "#{indentation}#{line}"
+    end
+  end
+
+private
+
+  def reset_marker
+    @marker = nil
+  end
+
+  def inside_heredoc?
+    !!marker
+  end
+
+  def set_heredoc_state(line)
+    @marker = extract_heredoc_marker(line)
+  end
+
+  def extract_heredoc_marker(line)
+    line =~ /<<-?\s*(\w+)/ ? $1 : nil
+  end
+
+  def heredoc_closed?(line)
+    inside_heredoc? && /^#{marker}\n?$/.match?(line)
+  end
+end

spec/bashly/indenter_spec.rb

@@ -0,0 +1,50 @@
+describe Indenter do
+  # this is tested through the array extension for convenience
+  subject { ['flat', '  indented', '    very indented'] }
+
+  describe '#indent' do
+    it 'prepends each element with the indentation string' do
+      expect(subject.indent(2)).to eq ['  flat', '    indented', '      very indented']
+    end
+
+    context 'when offset is 0' do
+      it 'returns the array as is' do
+        expect(subject.indent(0)).to eq subject
+      end
+    end
+
+    # context 'when the string contains heredoc block' do
+    #   subject do
+    #     result = <<~SUBJECT
+    #       function() {
+    #         cat <<-SOME_EOF_MARKER
+    #       not-indented
+    #         indented-once
+    #           indented-twice
+    #       SOME_EOF_MARKER
+    #       } # indented with function() start
+    #     SUBJECT
+
+    #     result.lines
+    #   end
+
+    #   let(:expected) do
+    #     result = <<~SUBJECT
+    #         function() {
+    #           cat <<-SOME_EOF_MARKER
+    #       not-indented
+    #         indented-once
+    #           indented-twice
+    #       SOME_EOF_MARKER
+    #         } # indented with function() start
+    #     SUBJECT
+
+    #     result.lines
+    #   end
+
+    #   it 'does not indent it but indents everything else' do
+    #     expect(subject.indent 2).to eq expected
+    #   end
+    # end
+  end
+end