module Iptablez
  module Commands
    module Policy 
      # Move on Module
      include MoveOn

      NO_CHAIN_MATCH_ERROR = 'iptables: No chain/target/match by that name.'.freeze
      KNOWN_ERRORS         = [NO_CHAIN_MATCH_ERROR].freeze
      
      # @api private
      # Determine a given error. Optionally a chain can be used to provide better context.
      private_class_method def self.determine_error(error:, chain: false)
        if error == NO_CHAIN_MATCH_ERROR
          raise ChainExistenceError, "#{chain} doesn't exist!"
        else
          raise error
        end
      end

      def self.all(target:, error: false, continue: !error)
        if target
          chains(names: Iptablez::Chains.defaults, target: target, continue: continue) do |result|
            yield result if block_given?
          end
        else
          Iptables::Chains.policies do |result|
            yield result
          end
        end  
      end

      def self.defaults(target:, error: false, continue: !error)
        chains(names: Iptablez::Chains.defaults, target: target, continue: continue) do |result|
          yield result if block_given?
        end
      end

      def self.chain(name:, target:, error: false, continue: !error)
        _, e, s = Open3.capture3(Iptablez.bin_path, '-P', name, target)      
        e.strip!
        if s.success?
          yield [name, target, true] if block_given?
          return true
        elsif MoveOn.continue?(continue: continue, message: e, known_errors: KNOWN_ERRORS)
          yield [name, target, false] if block_given?
          return false
        else
          determine_error(chain: name, error: e)
        end
      end

      def self.chains(names:, target:, error: false, continue: !error)
        results = {}
        names.each do |name|
          results[name] = {}
          results[name][target] = chain(name: name, target: target, continue: continue) do |result|
            yield result if block_given?
          end
        end
        results
      end

    end
  end
end