require 'earth/model'
require 'falls_back_on'

require 'earth/locality/egrid_region'
require 'earth/locality/electricity_mix'

class EgridSubregion < ActiveRecord::Base
  extend Earth::Model

  TABLE_STRUCTURE = <<-EOS

CREATE TABLE egrid_subregions
  (
     abbreviation                       CHARACTER VARYING(255) NOT NULL PRIMARY KEY,
     name                               CHARACTER VARYING(255),
     nerc_abbreviation                  CHARACTER VARYING(255),
     egrid_region_name                  CHARACTER VARYING(255),
     net_generation                     FLOAT,
     net_generation_units               CHARACTER VARYING(255),
     co2_emission_factor                FLOAT,
     co2_emission_factor_units          CHARACTER VARYING(255),
     co2_biogenic_emission_factor       FLOAT,
     co2_biogenic_emission_factor_units CHARACTER VARYING(255),
     ch4_emission_factor                FLOAT,
     ch4_emission_factor_units          CHARACTER VARYING(255),
     n2o_emission_factor                FLOAT,
     n2o_emission_factor_units          CHARACTER VARYING(255),
     electricity_emission_factor        FLOAT,
     electricity_emission_factor_units  CHARACTER VARYING(255)
  );

EOS

  self.primary_key = "abbreviation"
  
  belongs_to :egrid_region, :foreign_key => 'egrid_region_name'
  has_one :electricity_mix, :foreign_key => 'egrid_subregion_abbreviation'
  
  falls_back_on :name => 'fallback',
                :egrid_region => lambda { EgridRegion.fallback },
                :co2_emission_factor => lambda { weighted_average(:co2_emission_factor, :weighted_by => :net_generation) },
                :co2_emission_factor_units => 'kilograms_per_kilowatt_hour',
                :co2_biogenic_emission_factor => lambda { weighted_average(:co2_biogenic_emission_factor, :weighted_by => :net_generation) },
                :co2_biogenic_emission_factor_units => 'kilograms_per_kilowatt_hour',
                :ch4_emission_factor => lambda { weighted_average(:ch4_emission_factor, :weighted_by => :net_generation) },
                :ch4_emission_factor_units => 'kilograms_co2e_per_kilowatt_hour',
                :n2o_emission_factor => lambda { weighted_average(:n2o_emission_factor, :weighted_by => :net_generation) },
                :n2o_emission_factor_units => 'kilograms_co2e_per_kilowatt_hour',
                :electricity_emission_factor => lambda { weighted_average(:electricity_emission_factor, :weighted_by => :net_generation) },
                :electricity_emission_factor_units => 'kilograms_co2e_per_kilowatt_hour'
  
  warn_unless_size 26
  warn_if_any_nulls
end