module SplitVideo

# File lib/split_video.rb, line 16
def self.split_a_video(filename, options)
  unless (!! options['slices']) ^ (!! options['duration'])
    puts USAGE
    exit
  end

  if options['slices']
    SplitVideo.split_by_slices(filename, options['slices'].to_i, options)
  elsif options['duration']
    SplitVideo.split_by_duration(filename, options['duration'].to_i, options)
  end
end

# File lib/split_video.rb, line 48
def self.split_by_duration(filename, duration, options = {})
  puts "Sorry I haven't implemented this yet."
  exit
end

# File lib/split_video.rb, line 29
def self.split_by_slices(filename, num_slices, options = {})
  seconds_per_slice = duration_in_seconds(filename) / num_slices

  offset = 0.0
  (0..(num_slices - 1)).each do |slice|
    print "Cutting slice #{slice}"
    %x{
      ffmpeg -i      "#{filename}"            \
             -vcodec copy                     \
             -acodec copy                     \
             -ss     "#{offset}"              \
             -t      "#{seconds_per_slice}"   \
             #{output_filename_for(filename) % slice}
    }
    puts "...done!"
    offset += seconds_per_slice
  end
end

# File lib/split_video.rb, line 55
def self.duration_in_seconds(filename)
  duration_string = %x{ffmpeg -i #{filename} 2>&1 | grep Duration}
  duration_string =~ /(\d{2}):(\d{2}):(\d{2}.\d{2})/
  hours, minutes, seconds = [$1, $2, $3].map(&:to_f)

  hours * 3600 + minutes * 60 + seconds
end

# File lib/split_video.rb, line 63
def self.output_filename_for(filename)
  filename.gsub %r{\A(.*)\.([^\.]+)\Z}, '\1-part-%04d.\2'
end