fjord/ls.rb

# frozen_string_literal: true

require 'optparse'
require 'etc'

COLUMNS = 3
MARGIN = 3

def run
  listed_filenames = list_filenames
  filenames_matrix = slice_filenames(listed_filenames)
  filled_filenames = fill_filenames(filenames_matrix)
  arrange_filenames(filled_filenames)
end

def list_filenames
  params = ARGV.getopts('a', 'r', 'l')
  filenames = params['a'] ? Dir.glob('*', File::FNM_DOTMATCH) : Dir.glob('*')
  filenames = filenames.reverse if params['r']
  if params['l']
    ownerinfo(filenames)
    exit
  else
    filenames
  end
end

def ownerinfo(filenames)
  file_blocks(filenames)
  filenames.each do |file|
    file_stat = File::Stat.new(file)
    file_type(file_stat)
    permission(file_stat)
    print " #{file_stat.nlink}"
    print " #{Etc.getpwuid(file_stat.uid).name}"
    print " #{Etc.getgrgid(file_stat.gid).name}"
    print " #{file_stat.size}".rjust(file_size(filenames))
    timestamp(file_stat)
    symbolic(file)
    puts
  end
end

def symbolic(filenames)
  if File.lstat(filenames).symlink?
    print " #{filenames} -> #{File.readlink(filenames)}"
  else
    print " #{filenames}"
  end
end

def permission(file_stat)
  (-3..-1).each do |index|
    case file_stat.mode.to_s(8)[index]
    when '0' then print '---'
    when '1' then print '--x'
    when '2' then print '-w-'
    when '3' then print '-wx'
    when '4' then print 'r--'
    when '5' then print 'r-x'
    when '6' then print 'rw-'
    when '7' then print 'rwx'
    end
  end
end

def file_type(file_stat)
  {
    'fifo' => 'p',
    'characterSpecial' => 'c',
    'directory' => 'd',
    'blockSpecial' => 'b',
    'file' => '-',
    'link' => 'l',
    'socket' => 's'
  }[file_stat]
end

def file_size(filenames)
  filenames.map { |file| File.size(file) }.max.to_s.length + MARGIN
end

def timestamp(file_stat)
  print file_stat.mtime.strftime('%_m %_d %H:%M')
end

def file_blocks(filenames)
  blocks = filenames.map do |file|
    File::Stat.new(file).blocks
  end
  puts "total #{blocks.sum}"
end

def slice_filenames(listed_filenames)
  columns_size = listed_filenames.size.ceildiv(COLUMNS)
  listed_filenames.each_slice(columns_size).to_a
end

def fill_filenames(filenames_matrix)
  array_size = filenames_matrix.map(&:size).max
  filenames_matrix.each do |slice|
    slice << '' while slice.size < array_size
  end
  filenames_matrix.transpose
end

def arrange_filenames(filled_filenames)
  filenames_count = filled_filenames.flatten.map(&:size).max
  filled_filenames.each do |arrange|
    arrange.each do |arranged|
      print arranged.ljust(filenames_count + 5)
    end
    puts
  end
end

run