require 'stringio'
require 'pre-commit/checks/plugin'

module PreCommit
  module Checks
    class Rubocop < Plugin

      def self.aliases
        [ :rubocop_all, :rubocop_new ]
      end

      def self.excludes
        [ :ruby_symbol_hashrocket ]
      end

      def call(staged_files)
        require 'rubocop'
      rescue LoadError => e
        $stderr.puts "Could not find rubocop: #{e}"
      else
        staged_files = staged_files.grep(/\.rb$/)
        return if staged_files.empty?
        config_file = config.get('rubocop.config')

        args = staged_files
        if !config_file.empty?
          if !File.exist? config_file
            $stderr.puts "Warning: rubocop config file '" + config_file + "' does not exist"
            $stderr.puts "Set the path to the config file using:"
            $stderr.puts "\tgit config pre-commit.rubocop.config 'path/relative/to/git/dir/rubocop.yml'"
            $stderr.puts "Or in 'config/pre-commit.yml':"
            $stderr.puts "\trubocop.config: path/relative/to/git/dir/rubocop.yml"
            $stderr.puts "rubocop will use its default configuration or look for a .rubocop.yml file\n\n"
          else
            args = ['-c', config_file] + args
          end
        end

        success, captured = capture { ::Rubocop::CLI.new.run(args) == 0 }
        captured unless success
      end

      def capture
        $stdout, stdout = StringIO.new, $stdout
        $stderr, stderr = StringIO.new, $stderr
        result = yield
        [result, $stdout.string + $stderr.string]
      ensure
        $stdout = stdout
        $stderr = stderr
      end

      def self.description
        "Runs rubocop to detect errors."
      end
    end
  end
end