Implement Thor-like conflict handler

Author: elct9620

lib/boxing/generator.rb

@@ -7,10 +7,15 @@ module Boxing
   class Generator
     ASCII_CLEAR = "\e[0m"
     ASCII_BOLD = "\e[1m"
+    ASCII_RED = "\e[31m"
 
     CREATED_MESSAGE = "#{ASCII_BOLD}create#{ASCII_CLEAR}\t%s"
     IDENTICAL_MESSAGE = "#{ASCII_BOLD}identical#{ASCII_CLEAR}\t%s"
-    CONFLICT_MESSAGE = "#{ASCII_BOLD}conflict#{ASCII_CLEAR}\t%s"
+    CONFLICT_MESSAGE = "#{ASCII_BOLD}#{ASCII_RED}conflict#{ASCII_CLEAR}\t%s"
+    OVERWRITE_MESSAGE = 'Overwrite %s? (enter "h" for help) [Ynqdhm] '
+    FORCE_MESSAGE = "#{ASCII_BOLD}force#{ASCII_CLEAR}\t%s"
+    SKIP_MESSAGE = "#{ASCII_BOLD}skip#{ASCII_CLEAR}\t%s"
+    MERGE_TOOL_NOT_FOUND = 'Please configure merge.tool in your Git config.'
 
     attr_reader :destination, :path
 
@@ -84,12 +89,87 @@ def with_conflict(&block)
     #
     # @since 0.11.0
     def on_conflict
-      if identical?
-        puts format(IDENTICAL_MESSAGE, destination)
-        return
-      end
+      return puts format(IDENTICAL_MESSAGE, destination) if identical?
 
       puts format(CONFLICT_MESSAGE, destination)
+      return puts format(SKIP_MESSAGE, destination) unless do_overwrite
+
+      puts format(FORCE_MESSAGE, destination)
+      yield if block_given?
+    end
+
+    # Do overwrite
+    #
+    # @return [TrueClass|FalseClass]
+    # @raise [SystemExit] if user quits
+    #
+    # @api private
+    # @since 0.11.0
+    def do_overwrite # rubocop:disable Metrics/MethodLength, Metrics/CyclomaticComplexity
+      loop do
+        print format(OVERWRITE_MESSAGE, destination)
+
+        case $stdin.gets.chomp
+        when 'Y', 'y', '' then return true
+        when 'n', 'N' then return false
+        when 'd', 'D' then show_diff
+        when 'h', 'H' then show_help
+        when 'm', 'M'
+          puts MERGE_TOOL_NOT_FOUND unless do_merge
+          return false
+        when 'q', 'Q' then raise SystemExit
+        end
+      end
+    end
+
+    # Show diff
+    #
+    # @since 0.11.0
+    # @api private
+    def show_diff
+      Tempfile.open(destination) do |tempfile|
+        tempfile.write(render)
+        tempfile.rewind
+
+        system("diff -u #{tempfile.path} #{path}")
+      end
+    end
+
+    # Do merge
+    #
+    # @return [TrueClass|FalseClass]
+    #
+    # @since 0.11.0
+    # @api private
+    def do_merge # rubocop:disable Metrics/MethodLength
+      tool = begin
+        `git config merge.tool`.rstrip
+      rescue StandardError
+        ''
+      end
+      return false if tool.empty?
+
+      Tempfile.open(destination) do |tempfile|
+        tempfile.write(render)
+        tempfile.rewind
+
+        system("#{tool} #{tempfile.path} #{path}")
+      end
+    end
+
+    # Show help
+    #
+    # @since 0.11.0
+    # @api private
+    def show_help
+      puts <<-HELP
+        Y - yes, overwrite
+        n - no, do not overwrite
+        d - diff, show the differences between the old and the new
+        h - help, show this help
+        m - merge, run merge tool
+        q - quit, exit this program
+      HELP
     end
   end
 end