require 'yaml'
class WebResourceBundler::Settings

  DEFAULT_RESOURCE_DIR  = 'public'
  DEFAULT_SETTINGS_PATH = 'config/web_resource_bundler.yml'
  DEFAULT_CACHE_DIR     = 'cache'
  OBLIGATORY_SETTINGS   = [:resource_dir, :cache_dir]

  class << self

    attr_accessor :settings

    #creates settings from config file
    #and merging them with defaults
    def create_settings(rails_root, rails_env)
      config = self.read_from_file(rails_root, rails_env) 
      @settings = self.defaults(rails_root).merge(config)
      @settings
    end

    #ensures that settings has obligatory keys present
    def correct?(settings = @settings)
      OBLIGATORY_SETTINGS.each { |key| return false unless settings.has_key?(key) }
      true
    end

    #returns setting for particular filter, merged with common settings
    def filter_settings(filter_name)
      self.commons(@settings).merge(@settings[filter_name])
    end

    #setting request specific settings like domain and protocol
    def set_request_specific_data!(settings, domain, protocol)
      settings[:domain]   = domain
      settings[:protocol] = protocol
      settings
    end

    #sets new settings by merging with existing
    def set(settings)
      @settings.merge!(settings)
    end

		def filter_used?(name)
			@settings[name] && @settings[name][:use]
		end

    protected

    #load settings from yaml file depending on environment
    #if no settings found - returning empty hash
    def read_from_file(rails_root, rails_env)
      settings = {} 
      file_path = self.settings_file_path(rails_root) 
      if File.exist?(file_path)
        all_settings = YAML::load(File.open(file_path))
        if all_settings[rails_env]
          settings = all_settings[rails_env]
          settings[:resource_dir] = File.join(rails_root, DEFAULT_RESOURCE_DIR)
        end
      end
      settings
    end

    #returns path of config file
    def settings_file_path(rails_root)
      File.join(rails_root, DEFAULT_SETTINGS_PATH)
    end

    #creates defaults settings
    def defaults(rails_root)
      {
        :resource_dir    => File.join(rails_root, DEFAULT_RESOURCE_DIR),
        :cache_dir       => DEFAULT_CACHE_DIR,
        :bundle_filter   => {
					:use => true
				},
        :cdn_filter      => {
					:use => false
				},
        :base64_filter   => {
					:use            => true,
					:max_image_size => 20
			  },
				:compress_filter => {
					:use					=> false,
					:obfuscate_js => true
				}
      }
    end

    #settings common for all filters
    def commons(settings)
      {
        :resource_dir => settings[:resource_dir],
        :cache_dir    => settings[:cache_dir]
      }
    end

  end
end