require 'mongoid_location/location/core_ext'
require 'mongoid_location/location/geo_near_results'

module Mongoid
  module Location
    extend ActiveSupport::Concern

    LNG_SYMBOLS = [:x, :lon, :long, :lng, :longitude]
    LAT_SYMBOLS = [:y, :lat, :latitude]

    EARTH_RADIUS_KM = 6371 # taken directly from mongodb

    EARTH_RADIUS = {
      :km => EARTH_RADIUS_KM,
      :m  => EARTH_RADIUS_KM*1000,
      :mi => EARTH_RADIUS_KM*0.621371192, # taken directly from mongodb
      :ft => EARTH_RADIUS_KM*5280*0.621371192,
      :sm => EARTH_RADIUS_KM*0.53995680345572 # sea mile
    }

    GEO_FACTORY = RGeo::Geographic.spherical_factory
    RAD_PER_DEG = Math::PI/180
    mattr_accessor :lng_symbols
    @@lng_symbols = LNG_SYMBOLS.dup

    mattr_accessor :lat_symbols
    @@lat_symbols = LAT_SYMBOLS.dup

    mattr_accessor :earth_radius
    @@earth_radius = EARTH_RADIUS.dup

    mattr_accessor :paginator
    @@paginator = :array

    mattr_accessor :default_per_page
    @@default_per_page = 25

    # mattr_accessor :spherical_distance_formula
    # @@spherical_distance_formula = :n_vector
    mattr_accessor :geo_factory
    @@geo_factory = GEO_FACTORY.dup

    included do
      attr_accessor :geo
      cattr_accessor :spatial_fields, :spatial_fields_indexed
      @@spatial_fields = []
      @@spatial_fields_indexed = []
    end

    module ClassMethods #:nodoc:
      # create spatial index for given field
      # @param [String,Symbol] name
      # @param [Hash] options options for spatial_index

      def spatial_index name, options = {}
        self.spatial_fields_indexed << name
        if Mongoid::VERSION =~ /3.0/
          index({name => '2d'}, options)
        else
          index [[name, '2d']], options
        end
      end
    end

    # def distance(p2, opts = {})
    #   p1 = self.send(key)
    #   Mongoid::Location.distance(p1, p2, opts)
    # end

    # def self.distance(p1,p2,opts = {})
    #   opts[:formula] ||= (opts[:spherical]) ? @@spherical_distance_formula : :pythagorean_theorem
    #   p1 = p1.to_lng_lat if p1.respond_to?(:to_lng_lat)
    #   p2 = p2.to_lng_lat if p2.respond_to?(:to_lng_lat)

    #   rads = Formulas.send(opts[:formula], p1, p2)

    #   if unit = earth_radius[opts[:unit]]
    #     opts[:unit] = (rads.instance_variable_get("@radian")) ? unit : unit * RAD_PER_DEG
    #   end

    #   rads *= opts[:unit].to_f if opts[:unit]
    #   rads
    # end

  end
end