#!/usr/bin/env ruby

require 'dimensions'
require 'filemagic'
require 'fileutils'
require 'natural_sort'
require 'open3'
require 'pathname'
require 'slop'

#KOBO_PATH = '/media/KOBOeReader'
KOBO_PATH = '/home/wasa'

def pad_width(size)
  [2, Math.log10(size).floor + 1].max
end

def execute(command)
  _, stderr, status = Open3.capture3(*command)
  if status.to_i != 0
    puts stderr
  end
end

def process(file, digit, title)
  mime = FileMagic.mime
  # TODO use Dir.mktmpdir
  FileUtils.mkdir_p('/tmp/beam/unpack')
  FileUtils.mkdir_p('/tmp/beam/trash')
  # TODO use individual commands instead of aunpack
  execute(['aunpack', '-X', '/tmp/beam/unpack', file])

  # do a pass to unpack every archive inside
  Dir.glob('/tmp/beam/unpack/**/*').each do |f|
    mimetype = mime.file(f)
    if mimetype[/^application\/(zip|x-rar)/]
      puts 'Archive detected!', f
      FileUtils.chdir(Pathname(f).dirname)
      # TODO use individual commands instead of aunpack
      execute(['aunpack', f])
      FileUtils.mv(f, '/tmp/beam/trash')
    end
  end
  FileUtils.chdir('/tmp/beam/unpack')

  # do a pass to move every non-image file
  Dir.glob('/tmp/beam/unpack/**/*').reject { |f| File.directory?(f) }
                                   .each do |f|
    mimetype = mime.file(f)
    if !mimetype[/^image\//]
      FileUtils.mv(f, '/tmp/beam/trash')
    end
  end

  # do a pass to copy every image file naturally sorted to a flattened directory
  digits = pad_width(Dir.glob('/tmp/beam/unpack/**/*').size)
  FileUtils.mkdir_p('/tmp/beam/flatten')
  files = Dir.glob('/tmp/beam/unpack/**/*').reject { |f| File.directory?(f) }
  NaturalSort.sort(files).each_with_index do |f, i|
    index = "%0#{digits}i" % i
    FileUtils.cp(f, "/tmp/beam/flatten/#{index}_#{Pathname(f).basename}")
  end

  # do a pass to rotate every overly wide image in-place with IM by 270 degrees
  # TODO add an compression/downscaling/desaturation option
  Dir.glob('/tmp/beam/flatten/*').reject { |f| File.directory?(f) }.each do |f|
    width, height = Dimensions.dimensions(f)
    if width > height
      execute(['mogrify', '-rotate', '270', f])
    end
  end

  FileUtils.chdir('/tmp/beam/')
  # TODO rename directory to make unpacking it for debugging purposes
  # less annoying
  execute(['apack', 'output.zip'] + Dir.glob('flatten/*').sort)

  # move to correct place on kobo
  if title
    destination = "#{KOBO_PATH}/#{title}/#{title} ##{digit}.cbz"
  else
    bare_name = Pathname(file).basename.to_s.split(Pathname(file).extname)[0]
    destination = "#{KOBO_PATH}/#{bare_name} ##{digit}.cbz"
  end
  FileUtils.mv('/tmp/beam/output.zip', destination)

  # clean up temporary files
  FileUtils.chdir('/tmp')
  FileUtils.rm_rf('/tmp/beam')
end

opts = Slop.parse do
  banner 'Usage: beam [options] <files>'
  on 't', 'title=', 'Title of the manga'
  on 's', 'start=', 'Start counting from i', :as => Integer, :default => 1
end

opts.parse!
files = ARGV

if files.empty?
  puts opts
  exit(1)
end

if !File.exist?(KOBO_PATH)
  puts 'Kobo not mounted'
  exit(1)
end

if opts[:title] && !File.exist?("#{KOBO_PATH}/#{opts[:title]}")
  Dir.mkdir("#{KOBO_PATH}/#{opts[:title]}")
end

# TODO: sort case-insensitively
files = NaturalSort.sort(files.map { |f| Pathname(f).realpath.to_s })

number_of_files = files.size + opts[:start] - 1
files.each_index do |index|
  file = files[index]
  digit = "%0#{pad_width(number_of_files)}i" % (index + opts[:start])
  puts "Processing file ##{digit} (#{index + opts[:start]}/#{number_of_files}): #{file}"
  process(file, digit, opts[:title])
end