# require 'ffmprb/util/synchro'
require 'ffmprb/util/thread'
require 'ffmprb/util/io_buffer'

require 'open3'

module Ffmprb

  module Util

    class << self

      attr_accessor :ffmpeg_cmd, :ffprobe_cmd

      def ffprobe(*args)
        sh ffprobe_cmd, *args
      end

      def ffmpeg(*args)
        args = ['-loglevel', 'debug'] + args  if Ffmprb.debug
        sh ffmpeg_cmd, '-y', *args, output: :stderr
      end

      def sh(*cmd, output: :stdout, log: :stderr)
        cmd = cmd.to_a.map(&:to_s)
        cmd_str = cmd.join(' ')
        Ffmprb.logger.info cmd_str
        Open3.popen3(*cmd) do |stdin, stdout, stderr, wait_thr|
          stdin.close

          # XXX process timeouting/cleanup here will be appreciated

          begin
            log_cmd = "#{(cmd.respond_to?(:first)? cmd : cmd.split(' ')).first.upcase}: "  if log
            stdout_r = Reader.new(stdout, output == :stdout, log == :stdout && log_cmd)
            stderr_r = Reader.new(stderr, true, log == :stderr && log_cmd)

            raise Error, "#{cmd_str}:\n#{stderr_r.read}"  unless
              wait_thr.value.exitstatus == 0  # NOTE blocks

            # NOTE only one of them will return non-nil, see above
            stdout_r.read || stderr_r.read
          ensure
            begin
              stdout_r.join  if stdout_r
              stdout_r = nil
              stderr_r.join  if stderr_r
            rescue
              Ffmprb.logger.error "Thread joining error: #{$!.message}"
              stderr_r.join  if stdout_r
            end
            Ffmprb.logger.debug "FINISHED: #{cmd_str}"
          end
        end
      end

    end


    class Reader < Thread

      def initialize(input, store=false, log=nil)
        @output = ''
        @queue = Queue.new
        super "reader" do
          begin
            while s = input.gets
              Ffmprb.logger.debug log + s.chomp  if log
              @output << s  if store
            end
            @queue.enq @output
          rescue Exception
            @queue.enq Error.new("Exception in a reader thread")
          end
        end
      end

      def read
        case res = @queue.deq
        when Exception
          raise res
        when ''
          nil
        else
          res
        end
      end

    end

  end

end