module RuboCop::Git
# ref. https://github.com/thoughtbot/hound/blob/d2f3933/app/models/style_guide.rb
class StyleGuide
  def initialize(rubocop_options, config_file, override_config_content = nil)
    @rubocop_options = rubocop_options
    @config_file = config_file
    @override_config_content = override_config_content
  end

  def violations(file)
    if ignored_file?(file)
      []
    else
      parsed_source = parse_source(file)
      cops = RuboCop::Cop::Cop.all
      team = RuboCop::Cop::Team.new(cops, config, rubocop_options)
      team.inspect_file(parsed_source)
    end
  end

  private

  def ignored_file?(file)
    !file.ruby? || file.removed? || excluded_file?(file)
  end

  def excluded_file?(file)
    config.file_to_exclude?(file.filename)
  end

  def parse_source(file)
    if Gem::Version.new(RuboCop::Version::STRING) < Gem::Version.new('0.36.0')
      RuboCop::ProcessedSource.new(file.content, file.filename)
    else
      RuboCop::ProcessedSource.new(file.content,
                                   target_ruby_version, file.filename)
    end
  end

  def config
    if @config.nil?
      config = RuboCop::ConfigLoader.configuration_from_file(@config_file)
      combined_config = RuboCop::ConfigLoader.merge(config, override_config)
      @config = RuboCop::Config.new(combined_config, "")
    end

    @config
  end

  def rubocop_options
    if config["ShowCopNames"]
      { debug: true }
    else
      {}
    end.merge(@rubocop_options)
  end

  def override_config
    if @override_config_content
      config_content = YAML.load(@override_config_content)
      override_config = RuboCop::Config.new(config_content, "")
      override_config.add_missing_namespaces
      override_config.make_excludes_absolute
      override_config
    else
      {}
    end
  end

  def target_ruby_version
    @target ||= begin
      target = config['AllCops'] && config['AllCops']['TargetRubyVersion']

      if !target || !RuboCop::Config::KNOWN_RUBIES.include?(target)
        fail ValidationError, "Unknown Ruby version #{target.inspect} found " \
          'in `TargetRubyVersion` parameter (in ' \
          "#{loaded_path}).\nKnown versions: " \
          "#{RuboCop::Config::KNOWN_RUBIES.join(', ')}"
      end

      target
    end
  end
end
end