module Filbunke
  class Client

    UPDATES_ACTION = 'updates'
    FILES_ACTION = 'files'
    URL_KEY = 'url'
    FROM_CHECKPOINT_KEY = 'from_checkpoint'
    HASH_KEY = 'hash'

    def initialize(repository)
      @repository = repository
    end

    def with_updated_files(last_checkpoint, local_path)
      updates = get_updated_file_list(last_checkpoint)
      updated_files = updates["files"] || []
      updated_files.each do |raw_file|
        file = File.new(raw_file)
        if file.url.start_with?("http://")
          local_file_path = File.join(local_path, file.path)
          update_http_file!(file, local_file_path)
          yield file
        else
          raise "Unsupported protocol for file: #{file.inspect}"
        end
      end
      updates["checkpoint"] || last_checkpoint
    end

    def register_updated_file!(path, url, hash = nil)
      register_http = Net::HTTP.new(@repository.host, @repository.port)
      register_http.start do |http|
        register_path = "/#{FILES_ACTION}/#{@repository.name}/#{path}?#{URL_KEY}=#{url}"
        register_path += "&#{HASH_KEY}=#{hash}" if hash
        request = Net::HTTP::Put.new(register_path)
        response = http.request(request)
        if response.code.to_i != 204
          raise "Failed to register updated file: #{path}"
        end
      end
    end

    def register_deleted_file!(path)
      register_http = Net::HTTP.new(@repository.host, @repository.port)
      register_http.start do |http|
        register_path = "/#{FILES_ACTION}/#{@repository.name}/#{path}"
        request = Net::HTTP::Delete.new(register_path)
        response = http.request(request)
        if response.code.to_i != 204
          raise "Failed to register deleted file: #{path}"
        end
      end
    end

    private

    def get_updated_file_list(last_checkpoint)
      updates_http = Net::HTTP.new(@repository.host, @repository.port)
      updates_http.start do |http|
        updates_path = "/#{UPDATES_ACTION}/#{@repository.name}?#{FROM_CHECKPOINT_KEY}=#{last_checkpoint}"
        request = Net::HTTP::Get.new(updates_path)
        response = http.request(request)
        if response.code.to_i == 200
          JSON.parse(response.body)
        else
          raise "Failed to download updates for #{@repository.name}, error code = #{response.code}"
        end
      end
    end

    def update_http_file!(file, local_file_path)
      uri = URI.parse(file.url)
      file_http=Net::HTTP.new(uri.host, uri.port)
      file_http.start do |http|
        request = Net::HTTP::Get.new(uri.path)
        request.basic_auth @repository.user, @repository.pass if @repository.user
        response = http.request(request)
        if response.code.to_i == 200
          write_file!(local_file_path, response.body)
        elsif response.code.to_i == 404
          delete_file!(local_file_path)
        else
          raise "Failed to update file #{uri}, error code = #{response.code}"
        end
      end
    end

    def write_file!(file_path, contents)
      FileUtils.mkdir_p(File.dirname(file_path))
      File.open(file_path, 'w') do |file|
        file.write(contents);
        file.close
      end
    end

    def delete_file!(file_path)
      File.delete(file_path)
    end

  end
end