module Filbunke
  class Daemon

    def initialize(config, local = false)
      @config = config
      @clients = []
      setup_clients!(local)
      write_pid!(config["pid_file"]) unless local
    end

    def setup_clients!(local = false)
      @logger = Logger.new(@config["log_file"], local)
      @logger.log("Initializing filbunked")
      @config["repositories"].each do |repository_name, repository_config|
        @logger.log("Initializing repository: #{repository_name}")
        @clients << begin
          repository = Repository.new(repository_config["filbunke_server_repository"],
                                      repository_config["filbunke_server_host"],
                                      repository_config["filbunke_server_port"],
                                      repository_config["local_path"],
                                      repository_config["file_umask"].to_i,
                                      repository_config["directory_umask"].to_i,
                                      repository_config["file_url_username"],
                                      repository_config["file_url_password"],
                                      repository_config["hadoop_binary"])
          callbacks = []
          repository_config["callbacks"].each do |callback_name, callback_config|
            require ::File.join(@config["callback_path"], callback_name.to_s)
            callback_class =  Module.const_get(callback_name.split("_").map(&:capitalize).join)
            callbacks << callback_class.new(@logger, callback_config)
          end
          Client.new(repository, @logger, callbacks)
        end
      end
    end

    def run!
      version = ::File.read(::File.expand_path(::File.join(::File.dirname(__FILE__), "../../VERSION"))).chomp
      @logger.log("Starting filbunked version #{version}")
      while true
        begin
          @clients.each do |client|
            new_checkpoint = client.update_files!(checkpoint_for_repository(client.repository))
            update_checkpoint_for_repository(client.repository, new_checkpoint)
          end
        rescue StandardError => e
          @logger.log("Died.. #{e.message}")
          exit 1
        end
        sleep @config["run_every"]
      end
    end

    private

    def checkpoint_for_repository(repository)
      ::File.open(checkpoint_file_name_for_repository(repository), 'r') {|f| f.readline.to_i } rescue 0
    end

    def update_checkpoint_for_repository(repository, checkpoint)
      f = ::File.new(checkpoint_file_name_for_repository(repository), 'w', repository.file_umask)
      f.write(checkpoint)
      f.close
    end

    def checkpoint_file_name_for_repository(repository)
      FileUtils.mkdir_p(@config["checkpoint_path"], :mode => repository.directory_umask)
      ::File.join(@config["checkpoint_path"], repository.name + ".checkpoint")
    end

    def write_pid!(pid_file_path)
      ::File.open(pid_file_path, 'w') do |f|
        f.write(Process.pid.to_i)
        f.close
      end
    end

  end

end