# frozen_string_literal: true
require 'childprocess'

module NoradBeacon
  class Runner
    attr_reader :result_set, :exit_code

    # Class method to return results file
    def self.results_file
      @results_fn ||= "/tmp/norad.results.#{Time.now.strftime('%Y%m%d-%H%M%S')}"
    end

    # Initialize an instance of the Runner class
    #
    # @param prog [String] the program to execute
    # @param args [Array] list of arguments to pass to the program
    # @param timeout [Fixnum] optionally specify the timeout for the sub process
    # @return [NoradBeacon::Runner] an instance of the Runner class
    def initialize(prog, args, timeout = 600)
      raise ArgumentError, 'args must be an Array' unless args.is_a?(Array)
      @prog = prog
      @timeout = timeout
      @result_set = NoradBeacon::ResultSet.new
      @args = format_args(args)
      @exit_code = nil
    end

    # Execute the command
    def execute(stdout_results = false)
      process = ChildProcess.build(@prog, *@args)
      set_child_proc_io(process, stdout_results)
      process.start
      begin
        process.poll_for_exit(@timeout)
      rescue ChildProcess::TimeoutError
        puts 'Beacon Timeout reached. Stopping the process...'
        process.stop # tries increasingly harsher methods to kill the process.
      end
      @exit_code = process.exit_code
    end

    # Parse the results stored in the results file
    def parse_results
      raw_results = File.open(self.class.results_file, 'r')
      yield raw_results
      raw_results.close
    end

    private

    # Replaces the filename delimeter and any local options we need to override
    #
    # @param args [Array] list of arguments to format
    # @return [Array] formatted list of arguments
    def format_args(args)
      local_opts = NoradBeacon.container_options[(ENV['NORAD_SECURITY_CONTAINER_NAME'] || '').to_sym] || {}
      args.map do |arg|
        begin
          next format(arg, local_opts) if arg =~ /\A%\{[a-zA-Z_][a-zA-Z_0-9]*\}\z/
          arg
        rescue KeyError, ArgumentError
          arg
        end
      end.compact
    end

    def set_child_proc_io(process, stdout_results)
      if stdout_results
        process.io.stdout = File.open(self.class.results_file, 'w')
      else
        process.io.inherit!
      end
    end
  end
end