module FinApps
  module REST

    require 'erb'

    class Cashflows < FinApps::REST::Resources
      include FinApps::REST::Defaults

      # @param [Date] start_date
      # @param [Date] end_date
      # @return [Hash, Array<String>]
      def show(start_date, end_date)
        logger.debug "##{__method__.to_s} => Started"

        raise MissingArgumentsError.new 'Missing argument: start_date.' if start_date.blank?
        logger.debug "##{__method__.to_s} => start_date: #{start_date}"
        raise MissingArgumentsError.new 'Missing argument: end_date.' if end_date.blank?
        logger.debug "##{__method__.to_s} => end_date: #{end_date}"

        cashflow = Cashflow.new({:start_date => start_date,
                                 :end_date => end_date,
                                 :total_inflow_amount => 0,
                                 :total_outflow_amount => 0,
                                 :total_leftover_amount => 0,
                                 :details => []})

        end_point = Defaults::END_POINTS[:cashflow_show]
        logger.debug "##{__method__.to_s} => end_point: #{end_point}"

        path = end_point.sub(':start_date', ERB::Util.url_encode(start_date)).sub(':end_date', ERB::Util.url_encode(end_date))
        logger.debug "##{__method__.to_s} => path: #{path}"

        result, error_messages = @client.send(path, :get)
        if result.present? && error_messages.blank?

          summary = extract_value(result, 'summary')
          raise 'Summary result-set for cashflow is not present.' if summary.nil?
          raise 'Summary result-set for cashflow is not a hash.' unless summary.respond_to?(:key?)

          raise 'Total income (inflow) value for cashflow is not present.' unless summary.key?('inflow')
          cashflow.total_income_amount = summary['inflow']

          raise 'Total expenses (outflow) value for cashflow is not present.' unless summary.key?('outflow')
          cashflow.total_expenses_amount = summary['outflow']

          raise 'Total left-over (diff) value for cashflow is not present.' unless summary.key?('diff')
          cashflow.total_leftover_amount = summary['diff']

          categories = extract_value(result, 'details')
          raise 'Category results-set for cashflow is not an array.' unless categories.respond_to?(:each)

          categories.each { |category| cashflow.details << result_category_to_cashflow_detail(category) }
        end

        logger.debug "##{__method__.to_s} => Completed"
        return cashflow, error_messages
      end

      private

      def extract_value(result, array_identifier)
        array_container = result.find { |r| r.has_key?(array_identifier) }
        array_container.present? ? array_container[array_identifier] : nil
      end

      def result_category_to_cashflow_detail(category)
        raise 'Unable to locate category id for current category record.' unless category.key?('cat')
        category_id = category['cat']

        raise 'Unable to locate inflow amount for current category record.' unless category.key?('inflow')
        inflow_amount = category['inflow']

        raise 'Unable to locate outflow amount for current category record.' unless category.key?('outflow')
        outflow_amount = category['outflow']

        raise 'Unable to locate left over amount for current category record.' unless category.key?('diff')
        leftover_amount = category['diff']

        BudgetDetail.new({:category_id => category_id,
                          :inflow_amount => inflow_amount,
                          :outflow_amount => outflow_amount,
                          :leftover_amount => leftover_amount})
      end

    end

    class Cashflow < FinApps::REST::Resource
      attr_accessor :start_date, :end_date,
                    :total_income_amount, :total_expenses_amount, :total_leftover_amount, :details
    end

    class CashflowDetail < FinApps::REST::Resource
      attr_accessor :category_id, :income_amount, :expenses_amount, :leftover_amount
    end

  end
end