# encoding: utf-8

module RuboCop
  module Formatter
    # This formatter displays a YAML configuration file where all cops that
    # detected any offenses are configured to not detect the offense.
    class DisabledConfigFormatter < BaseFormatter
      HEADING =
        ['# This configuration was generated by',
         '# `%s`',
         "# on #{Time.now} using RuboCop version #{Version.version}.",
         '# The point is for the user to remove these configuration records',
         '# one by one as the offenses are removed from the code base.',
         '# Note that changes in the inspected code, or installation of new',
         '# versions of RuboCop, may require this file to be generated again.']
        .join("\n")

      @config_to_allow_offenses = {}

      COPS = Cop::Cop.all.group_by(&:cop_name)

      class << self
        attr_accessor :config_to_allow_offenses
      end

      def file_started(_file, file_info)
        @exclude_limit_option =
          file_info.fetch(:cli_options, {})[:exclude_limit]
        @exclude_limit = (
          @exclude_limit_option ||
          RuboCop::Options::DEFAULT_MAXIMUM_EXCLUSION_ITEMS).to_i
      end

      def file_finished(file, offenses)
        @cops_with_offenses ||= Hash.new(0)
        @files_with_offenses ||= {}
        offenses.each do |o|
          @cops_with_offenses[o.cop_name] += 1
          @files_with_offenses[o.cop_name] ||= []
          @files_with_offenses[o.cop_name] << file
        end
      end

      def finished(_inspected_files)
        command = 'rubocop --auto-gen-config'
        if @exclude_limit_option
          command += format(' --exclude-limit %d', @exclude_limit_option.to_i)
        end
        output.puts HEADING % command

        # Syntax isn't a real cop and it can't be disabled.
        @cops_with_offenses.delete('Syntax')

        @cops_with_offenses.sort.each do |cop_name, offense_count|
          output.puts
          cfg = self.class.config_to_allow_offenses[cop_name]
          cfg ||= {}
          output_cop_comments(output, cfg, cop_name, offense_count)
          output_cop_config(output, cfg, cop_name)
        end
        puts "Created #{output.path}."
        puts "Run `rubocop --config #{output.path}`, or"
        puts "add inherit_from: #{output.path} in a .rubocop.yml file."
      end

      def output_cop_comments(output, cfg, cop_name, offense_count)
        output.puts "# Offense count: #{offense_count}"
        if COPS[cop_name] && COPS[cop_name].first.new.support_autocorrect?
          output.puts '# Cop supports --auto-correct.'
        end

        default_cfg = RuboCop::ConfigLoader.default_configuration[cop_name]
        return unless default_cfg

        params = default_cfg.keys -
                 %w(Description StyleGuide Reference Enabled) -
                 cfg.keys
        return if params.empty?

        output.puts "# Configuration parameters: #{params.join(', ')}."
      end

      def output_cop_config(output, cfg, cop_name)
        output.puts "#{cop_name}:"
        cfg.each do |key, value|
          value = value[0] if value.is_a?(Array)
          output.puts "  #{key}: #{value}"
        end
        output_offending_files(output, cfg, cop_name)
      end

      def output_offending_files(output, cfg, cop_name)
        return unless cfg.empty?

        offending_files = @files_with_offenses[cop_name].uniq.sort
        if offending_files.count > @exclude_limit
          output.puts '  Enabled: false'
        else
          output_exclude_list(output, offending_files, cop_name)
        end
      end

      def output_exclude_list(output, offending_files, cop_name)
        require 'pathname'
        parent = Pathname.new(Dir.pwd)

        # Exclude properties in .rubocop_todo.yml override default ones, so in
        # order to retain the default excludes we must copy them.
        default_cfg = RuboCop::ConfigLoader.default_configuration[cop_name]
        default_excludes = default_cfg ? default_cfg['Exclude'] || [] : []

        output.puts '  Exclude:'
        (default_excludes + offending_files).each do |file|
          file_path = Pathname.new(file)
          begin
            relative = file_path.relative_path_from(parent)
            output.puts "    - '#{relative}'"
          rescue ArgumentError
            output.puts "    - '#{file}'"
          end
        end
      rescue LoadError
        # Fallback to Enabled: false for Ruby < 1.9.3
        output.puts '  Enabled: false'
      end
    end
  end
end