require 'babel/hash_filter'
module Babel
  class Serializer

    def initialize(model_or_models)
      @model_or_models = model_or_models
    end
    
    def respond_to?(method)
      @model_or_models.respond_to?(method)
    end

    def method_missing(method, *args, &block)
      @model_or_models.send(method, *args, &block)
    end
    
    private

    def self.filter
      @filter ||= HashFilter.new
    end

    def filter
      @filter ||= self.class.filter.dup
    end

    protected

    # for rails
    def self.model(model = nil)
      @model_class = model if model
      @model_class ||= self.to_s.sub(/Serializer$/, '').constantize
    end

    # for rails
    def self.model_name
      model.model_name
    end

    def self.default_context_key(default)
      filter.default_context_key(default)
    end

    def self.add_context(key, options = {})
      filter[key] = options
    end

    public

    def use(context_or_options)
      filter.use(context_or_options)
      self
    end

    def to_hash(options = nil)
      filter.use(options) if options
      case @model_or_models
      when Array
        @model_or_models.collect do |m|
          filter_model(attr(m), m)
        end
      else
        filter_model(attr(@model_or_models), @model_or_models)
      end
    end

    def to_json(options = nil)
      to_hash(options).to_json
    end

    def to_xml(options = nil)
      opts = fitler.options.dup
      root = opts.delete :root
      fitler.use(opts)
      result = to_hash
      if root && result.is_a?(Array) && root.respond_to?(:pluralize)
        root = root.to_s.pluralize
      end
      result.to_xml :root => root
    end

    def to_yaml(options = nil)
      to_hash(options).to_yaml
    end
    
    protected

    def attr(model)
      model.attributes if model
    end

    private

    def filter_model(model, data)
      if root = filter.options[:root]
        {root.to_s => filter.filter(model, data){ |model| attr(model) } }
      else
        filter.filter(model, data){ |model| attr(model) }
      end
    end 
  end
end