module Spigot
  module ActiveRecord
    module ClassMethods
      ## #find_by_api(params)
      # Build a query based on the defined map for this resource
      # to find a single matching record in the database
      #
      # @param params [Hash] Data as received from the api with optional service key
      def find_by_api(params = {})
        find_all_by_api(params).first
      end

      ## #find_all_by_api(params)
      # Build a query based on the defined map for this resource
      # to find all matching records in the database.
      #
      # @param params [Hash] Data as received from the api with optional service key
      def find_all_by_api(params = {})
        find_by_translator params_to_translator(params)
      end

      ## #create_by_api(params)
      # Insert mapped data into the calling model's table. Does not
      # perform any checks on existing content already present in the database
      #
      # @param params [Hash] Data as received from the api with optional service key
      def create_by_api(params = {})
        create_by_translator params_to_translator(params)
      end

      ## #update_by_api(params)
      # Queries the database to find an existing record.
      # If a record is found, it updates that record
      # with any new formatted data received by the API
      #
      # @param params [Hash] Data as received from the api with optional service key
      def update_by_api(params = {})
        babel = params_to_translator(params)
        record = find_by_translator(babel).first
        update_by_translator(babel, record) if record.present?
      end

      ## #find_or_create_by_api(params)
      # Queries the database to find an existing record. If that record is found
      # simply return it, otherwise return a newly created record. This does
      # not update any existing record. If you want that, use `create_or_update_by_api`
      #
      # @param params [Hash] Data as received from the api with optional service key
      def find_or_create_by_api(params = {})
        babel = params_to_translator(params)
        find_by_translator(babel).first || create_by_translator(babel)
      end

      ## #create_or_update_by_api(params)
      # Queries the database to find an existing record. If that record is found
      # it updates it with passed api_data and returns the record. Otherwise it
      # creates a new record and returns the newly created record.
      #
      # @param params [Hash] Data as received from the api with optional service key
      def create_or_update_by_api(params = {})
        babel = params_to_translator(params)
        record = find_by_translator(babel).first
        record.present? ? update_by_translator(babel, record) : create_by_translator(babel)
      end

      private

      def params_to_translator(params)
        service, data = Spigot::Map::Service.extract(params)
        Translator.new(self, service, data)
      end

      def find_by_translator(translator)
        if invalid_primary_keys?(translator)
          message = "The #{translator.primary_key} column does not exist on #{to_s}"
          raise Spigot::InvalidSchemaError, message
        end

        return [] if translator.conditions.blank?
        where(translator.conditions)
      end

      def create_by_translator(translator)
        Record.create(translator.service, self, translator.format)
      end

      def update_by_translator(translator, record)
        Record.update(translator.service, self, record, translator.format)
        record
      end

      def invalid_primary_keys?(translator)
        [*translator.primary_key].each do |key|
          return true unless column_names.include?(key.to_s)
        end
        false
      end
    end
  end
end