module Backup
  class Manager
    ARCHIVES_TO_BACKUP = %w[uploads builds artifacts lfs registry]
    FOLDERS_TO_BACKUP = %w[repositories db]

    def pack
      # Make sure there is a connection
      ActiveRecord::Base.connection.reconnect!

      # saving additional informations
      s = {}
      s[:db_version]         = "#{ActiveRecord::Migrator.current_version}"
      s[:backup_created_at]  = Time.now
      s[:gitlab_version]     = Gitlab::VERSION
      s[:tar_version]        = tar_version
      s[:skipped]            = ENV["SKIP"]
      tar_file = "#{s[:backup_created_at].to_i}_gitlab_backup.tar"

      Dir.chdir(Gitlab.config.backup.path) do
        File.open("#{Gitlab.config.backup.path}/backup_information.yml",
                  "w+") do |file|
          file << s.to_yaml.gsub(/^---\n/,'')
        end

        # create archive
        $progress.print "Creating backup archive: #{tar_file} ... "
        # Set file permissions on open to prevent chmod races.
        tar_system_options = {out: [tar_file, 'w', Gitlab.config.backup.archive_permissions]}
        if Kernel.system('tar', '-cf', '-', *backup_contents, tar_system_options)
          $progress.puts "done".green
        else
          puts "creating archive #{tar_file} failed".red
          abort 'Backup failed'
        end

        upload(tar_file)
      end
    end

    def upload(tar_file)
      remote_directory = Gitlab.config.backup.upload.remote_directory
      $progress.print "Uploading backup archive to remote storage #{remote_directory} ... "

      connection_settings = Gitlab.config.backup.upload.connection
      if connection_settings.blank?
        $progress.puts "skipped".yellow
        return
      end

      connection = ::Fog::Storage.new(connection_settings)
      directory = connection.directories.create(key: remote_directory)

      if directory.files.create(key: tar_file, body: File.open(tar_file), public: false,
          multipart_chunk_size: Gitlab.config.backup.upload.multipart_chunk_size,
          encryption: Gitlab.config.backup.upload.encryption)
        $progress.puts "done".green
      else
        puts "uploading backup to #{remote_directory} failed".red
        abort 'Backup failed'
      end
    end

    def cleanup
      $progress.print "Deleting tmp directories ... "

      backup_contents.each do |dir|
        next unless File.exist?(File.join(Gitlab.config.backup.path, dir))

        if FileUtils.rm_rf(File.join(Gitlab.config.backup.path, dir))
          $progress.puts "done".green
        else
          puts "deleting tmp directory '#{dir}' failed".red
          abort 'Backup failed'
        end
      end
    end

    def remove_old
      # delete backups
      $progress.print "Deleting old backups ... "
      keep_time = Gitlab.config.backup.keep_time.to_i

      if keep_time > 0
        removed = 0

        Dir.chdir(Gitlab.config.backup.path) do
          file_list = Dir.glob('*_gitlab_backup.tar')
          file_list.map! { |f| $1.to_i if f =~ /(\d+)_gitlab_backup.tar/ }
          file_list.sort.each do |timestamp|
            if Time.at(timestamp) < (Time.now - keep_time)
              if Kernel.system(*%W(rm #{timestamp}_gitlab_backup.tar))
                removed += 1
              end
            end
          end
        end

        $progress.puts "done. (#{removed} removed)".green
      else
        $progress.puts "skipping".yellow
      end
    end

    def unpack
      Dir.chdir(Gitlab.config.backup.path)

      # check for existing backups in the backup dir
      file_list = Dir.glob("*_gitlab_backup.tar").each.map { |f| f.split(/_/).first.to_i }
      puts "no backups found" if file_list.count == 0

      if file_list.count > 1 && ENV["BACKUP"].nil?
        puts "Found more than one backup, please specify which one you want to restore:"
        puts "rake gitlab:backup:restore BACKUP=timestamp_of_backup"
        exit 1
      end

      tar_file = ENV["BACKUP"].nil? ? File.join("#{file_list.first}_gitlab_backup.tar") : File.join(ENV["BACKUP"] + "_gitlab_backup.tar")

      unless File.exists?(tar_file)
        puts "The specified backup doesn't exist!"
        exit 1
      end

      $progress.print "Unpacking backup ... "

      unless Kernel.system(*%W(tar -xf #{tar_file}))
        puts "unpacking backup failed".red
        exit 1
      else
        $progress.puts "done".green
      end

      ENV["VERSION"] = "#{settings[:db_version]}" if settings[:db_version].to_i > 0

      # restoring mismatching backups can lead to unexpected problems
      if settings[:gitlab_version] != Gitlab::VERSION
        puts "GitLab version mismatch:".red
        puts "  Your current GitLab version (#{Gitlab::VERSION}) differs from the GitLab version in the backup!".red
        puts "  Please switch to the following version and try again:".red
        puts "  version: #{settings[:gitlab_version]}".red
        puts
        puts "Hint: git checkout v#{settings[:gitlab_version]}"
        exit 1
      end
    end

    def tar_version
      tar_version, _ = Gitlab::Popen.popen(%W(tar --version))
      tar_version.force_encoding('locale').split("\n").first
    end

    def skipped?(item)
      settings[:skipped] && settings[:skipped].include?(item) || disabled_features.include?(item)
    end

    private

    def backup_contents
      folders_to_backup + archives_to_backup + ["backup_information.yml"]
    end

    def archives_to_backup
      ARCHIVES_TO_BACKUP.map{ |name| (name + ".tar.gz") unless skipped?(name) }.compact
    end

    def folders_to_backup
      FOLDERS_TO_BACKUP.reject{ |name| skipped?(name) }
    end

    def disabled_features
      features = []
      features << 'registry' unless Gitlab.config.registry.enabled
      features
    end

    def settings
      @settings ||= YAML.load_file("backup_information.yml")
    end
  end
end