class RSpec::Expectations::Differ

def blue(text)
  color(text, 34)
end

def color(text, color_code)
  "\e[#{color_code}m#{text}\e[0m"
end

def color_diff(diff)
  return diff unless RSpec::Matchers.configuration.color?
  diff.lines.map { |line|
    case line[0].chr
    when "+"
      green line
    when "-"
      red line
    when "@"
      line[1].chr == "@" ? blue(line) : line
    else
      line
    end
  }.join
end

def context_lines
  3
end

def diff_as_object(actual, expected)
  actual_as_string = object_to_string(actual)
  expected_as_string = object_to_string(expected)
  if diff = diff_as_string(actual_as_string, expected_as_string)
    color_diff diff
  end
end

def diff_as_string(input_data_new, input_data_old)
  encoding = pick_encoding input_data_new, input_data_old
  output = matching_encoding("", encoding)
  data_old = input_data_old.split(matching_encoding("\n", encoding)).map! { |e| e.chomp }
  data_new = input_data_new.split(matching_encoding("\n", encoding)).map! { |e| e.chomp }
  diffs = Diff::LCS.diff(data_old, data_new)
  return output if diffs.empty?
  oldhunk = hunk = nil
  file_length_difference = 0
  diffs.each do |piece|
    begin
      hunk = Diff::LCS::Hunk.new(
        data_old, data_new, piece, context_lines, file_length_difference
      )
      file_length_difference = hunk.file_length_difference
      next unless oldhunk
      # Hunks may overlap, which is why we need to be careful when our
      # diff includes lines of context. Otherwise, we might print
      # redundant lines.
      if (context_lines > 0) and hunk.overlaps?(oldhunk)
        if hunk.respond_to?(:merge)
          # diff-lcs 1.2.x
          hunk.merge(oldhunk)
        else
          # diff-lcs 1.1.3
          hunk.unshift(oldhunk)
        end
      else
        output << matching_encoding(oldhunk.diff(format).to_s, encoding)
      end
    ensure
      oldhunk = hunk
      output << matching_encoding("\n", encoding)
    end
  end
  #Handle the last remaining hunk
  output << matching_encoding(oldhunk.diff(format).to_s, encoding)
  output << matching_encoding("\n", encoding)
  color_diff output
rescue Encoding::CompatibilityError
  if input_data_new.encoding != input_data_old.encoding
    "Could not produce a diff because the encoding of the actual string (#{input_data_old.encoding}) "+
    "differs from the encoding of the expected string (#{input_data_new.encoding})"
  else
    "Could not produce a diff because of the encoding of the string (#{input_data_old.encoding})"
  end
end

def format
  :unified
end

def green(text)
  color(text, 32)
end

def matching_encoding(string, encoding)
  string.encode encoding
rescue Encoding::UndefinedConversionError
  string.encode(encoding, :undef => :replace)
end

def matching_encoding(string, encoding)
  string
end

def object_to_string(object)
  case object
  when Hash
    object.keys.sort_by { |k| k.to_s }.map do |key|
      pp_key   = PP.singleline_pp(key, "")
      pp_value = PP.singleline_pp(object[key], "")
      # on 1.9.3 PP seems to minimise to US-ASCII, ensure we're matching source encoding
      #
      # note, PP is used to ensure the ordering of the internal values of key/value e.g.
      # <# a: b: c:> not <# c: a: b:>
      encoding = pick_encoding pp_key, pp_value
      matching_encoding("#{pp_key} => #{pp_value}", encoding)
    end.join(",\n")
  when String
    object =~ /\n/ ? object : object.inspect
  else
    PP.pp(object,"")
  end
end

def pick_encoding(source_a, source_b)
  Encoding.compatible?(source_a, source_b) || Encoding.default_external
end

def pick_encoding(source_a, source_b)
end

def red(text)
  color(text, 31)
end