require 'active_record'

module Livelist
  module Rails
    module ActiveRecord

      def filters(*filter_slugs)
        @@filter_slugs = filter_slugs
        @@filter_slugs.each do |filter_slug|
          filter_slug = filter_slug.to_s
          metaclass = class << self; self; end

          metaclass.instance_eval do
            define_method "#{filter_slug}_filter_name" do
              filter_slug.capitalize
            end

            define_method "#{filter_slug}_filter_slug" do
              filter_slug
            end

            define_method "#{filter_slug}_filter" do |options|
              {
                :filter_slug => send("#{filter_slug}_filter_slug"),
                :name => send("#{filter_slug}_filter_name"),
                :options => options
              }
            end

            define_method "#{filter_slug}_filter_values" do
              select("distinct #{filter_slug}").map(&filter_slug.to_sym)
            end

            define_method "#{filter_slug}_filter_counts" do
              group(filter_slug).count
            end

            define_method "#{filter_slug}_filter_option_slug" do |option|
              option.to_s
            end

            define_method "#{filter_slug}_filter_option_name" do |option|
              option.to_s.capitalize
            end

            define_method "#{filter_slug}_filter_option_value" do |option|
              option.to_s
            end

            define_method "#{filter_slug}_filter_option_count" do |option|
              unless class_variables.include?("@@#{filter_slug}_filter_counts")
                class_variable_set(:"@@#{filter_slug}_filter_counts", send("#{filter_slug}_filter_counts"))
              end
              class_variable_get(:"@@#{filter_slug}_filter_counts")[option]
            end

            define_method "#{filter_slug}_filter_option" do |option, selected|
              {
                :slug => send("#{filter_slug}_filter_option_slug", option),
                :name => send("#{filter_slug}_filter_option_name", option),
                :value => send("#{filter_slug}_filter_option_value", option),
                :count => send("#{filter_slug}_filter_option_count", option),
                :selected => selected
              }
            end

            define_method "#{filter_slug}_filter_option_selected?" do |filter_params, option|
              filter_params.nil? ? true : filter_params.include?(option)
            end

            define_method "#{filter_slug}_filters" do |filter_params|
              send("#{filter_slug}_filter_values").map do |option|
                selected = send("#{filter_slug}_filter_option_selected?", filter_params, option)
                send("#{filter_slug}_filter_option", option, selected)
              end
            end

            define_method "#{filter_slug}_relation" do |values|
              where(model_name.to_s.tableize => { filter_slug => values })
            end
          end
        end

        def self.filters_as_json(filter_params)
          filter_params ||= {}
          @@filter_slugs.map do |filter|
            filter_options = send("#{filter}_filters", filter_params[filter])
            send("#{filter}_filter", filter_options)
          end
        end

        def self.filter(filter_params)
          filter_params ||= {}
          query = scoped
          filter_params.each do |filter, values|
            query = query.send("#{filter}_relation", values)
          end
          query
        end
      end

    end
  end
end