require 'logger'
require 'shellwords'

module Daemonic
  class Configuration

    Invalid = Class.new(ArgumentError)

    attr_reader :eventual_config, :given_options

    def initialize(given_options, pwd)
      @given_options = given_options
      @pwd = pwd
      @eventual_config = {}
    end

    def command
      self[:command]
    end

    def daemonize?
      self[:daemonize]
    end

    def config_file
      self[:config_file]
    end

    def workers
      Integer(self[:workers] || "1")
    end

    def reload
      @eventual_config = {}
      @logger = nil
      load_options defaults
      load_options given_options
      load_options config_file_options if config_file
      load_options given_options
      logger.debug { to_h.inspect }
      validate
    end

    def working_dir
      self[:working_dir]
    end

    def program_name
      self[:program_name] || File.basename(working_dir)
    end

    def pidfile
      self[:pidfile] || File.join(working_dir, "tmp/#{program_name}.pid")
    end

    def logfile
      self[:logfile] || STDOUT
    end

    def logger
      @logger ||= ::Logger.new(logfile).tap { |logger|
        logger.formatter = proc { |severity, datetime, progname, msg|
          "[#{severity}] [#{datetime}] [#{program_name}] [#{Process.pid}] #{msg}\n"
        }
        logger.level = ::Logger.const_get(loglevel)
      }
    end

    def to_h
      eventual_config
    end

    def loglevel
      (self[:loglevel] || "INFO").to_s.upcase
    end

    protected

    def [](key)
      eventual_config[key.to_s]
    end

    def []=(key, value)
      eventual_config[key.to_s] = value
    end

    private

    def load_options(options)
      options.each do |key, value|
        self[key] = value
      end
    end

    def config_file_options
      contents = File.open(config_file, 'r:utf-8').read
      args = Shellwords.split(contents)
      CLI.parse(args)
    end

    def validate
      raise Invalid, "No command specified" if command.nil?
    end

    def defaults
      { :workers => 1, :working_dir => @pwd }
    end

  end
end